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CIE 70-1987 the measurement of absolute luminous intensity distribution (绝对光强的测量)


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CIE 7 0 87

9006345 0003038 703

COMMISSION INTERNATIONALE DE L'ECLAIRAGE INTERNATIONAL COMMISSION ON ILLUMINATI

ON INTERNATIONALE BELEUCHTUNGSKOMMISSION

THE MEASUREMENT OF ABSOLUTE LUMINOUS INTENSITY DISTRIBUTIONS

PUBLICATION CIE Ni) 70 (1987) CENTRAL BUREAU OF THE CIE A-I033 VIENNA. P. O B X 159 O

AUSTRIA

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C I E 70 87 I9006145 0003019 6 4 T

This Technical Report has been prepared by CIE Technical Committee 2.2 Detectoorc (now within CIE Division 2) and has been approved by the Council o f the Commission Internationale de 1'Eclairage for study and application. The document reports on current knowledge and experience within the specific field o f light and lighting described, and is intended to be used by the CIE membership and other interested parties. i t should be noted, however, that the status of this document is advisory and not mandatory. The latest CIE proceedings or Journal should be consulted regarding possible subsequent amendments. Ce rapport technique a été préparé par le Comité Technique CIE 2.2, Détecteurs (maintenant partie de la Division 2 de la CIE), et a été approuvé, par le Consei 1 de 1a Commi ssi on Internationale de 1 ' Ecl ai rage, pour étude et application. Le document traite des connaissances courantes et de l'expérience dans l e domaine spécifique indiqué de la lumiére et de l'éclairage, et i l est établi pour l'usage des membres de la CIE et autres groupements intéressés. Il faut cependant noter que ce document est indicatif et non obligatoire. Pour connai tre d 'éventuels amendements, consulter les plus récents comptesrendus ou le Journal de la CIE. Dieser Technische Bericht ist vom CIE-Technischen Komitee 2.2 Detektoren (z.Z. i n der CIE Division 2) ausgearbeitet und vom Rat der Commission Internationale de 1'Eclairage gebilligt worden. Das Dokument berichtet über den derzeitigen Stand von Wissen und Erfahrung in dem behandelten Gebiet von Licht und Beleuchtung; es ist zur Verwendung durch CIE- Mitglieder und durch andere Interessierte bestimmt. Es sollte jedoch beachtet werden, da6 das Dokument eine Empfehlung und keine Vorschrift ist. Die neue- sten CIE-Tagungsberichte oder das neueste CIE-Journal sollten im Hinblick auf m?gliche sp?tere ?nderungen zu Rate gezogen werden.
y Any mention o f organisations or products does not imply endorsement b the CIE. Whilst every care has been taken in the compilation of any lists, up to the time of going to press, these may not be comprehensive.

Toute mention d'organisme ou de produit n'implique pas une préférence de la CIE. Malgré le soin apporté 4 la compilation de tous ?es documents jusqu'à l a mise sous presse, ce travail ne saurait être exhaustif. Die Erw?hnung von Organisationen oder Erzeugnissen bedeutet keine Billigung durch die CIE. Obgleich gro?e Sorgfalt bei der Erstellung von Verzeichnissen b i s zum Zeitpunkt der Druck1 egung angewendet wurde, i st es m?glich, da? diese nicht vollst?ndig sind.
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CIE 1987

II

CIE 70 8 7

9006145 0003020 3 b L

The f o l l o w i n g members o f Committee TC-2.2

took p a r t i n t h e p r e p a r t i o n o f

the technical report: Les membres s u i v a n t du c o m i t é TC-2.2 o n t p a r t i c i p é s a l a p r e p a r a t i o n du r a p p o r t technique: Die folgenden M i t a r b e i t e r d e s Komitees TC-2.2 haben s i c h an der Ausarbeitung d e s Technischen B e r i c h t e s b e t e i l i g t :
Chairman:

H e n g s t b e r g e r , F*
Cogno, J A Farmer, A J D

South Africa Argentina Australia Austria Belgium Bulgaria Canada Czechoslovakia Denmark France Finland Germany, Dem. Rep. Germany, Fed. Rep. Great B r i t a i n Hungary Italy Japan Netherlands Norway Poland Romania Spain Sweden Switzerland USA
U S S R

Reiter, H* Pactiels, R
Andreytchine, R Budde, W Krt i l , J Nielsen, O* Janest, A Timonen, T Riemann, M Geutler, G Betts, D B Schanda, J* Artom, M Nanjo, M Balder, J J Hisdal, B Lipowski, M Musa, G Corrons, A* Ottoson, A

Blaser, P*
Zalewcki, E F Ignatiev, V G

Subcommittee on "Measurement o f luminous i n t e n s i t y d i s t r i b u t i o n s " :

Chairman: Krochmann, J

Germany, Fed. Rep. Austria Belgium France

Rotter, F Vandermeersch, M G Bastie, J

III

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CIE 70 87

9006345 0003021 2 T B

Moore,

3 R

Rattunde, R F?rste, D Dezsi, G Gentile, C d e Groot, J J De Veer, S M
and members o f TC-2.2

Great B r i t a i n Germany, Fed. Rep. Germany, Fed. Rep. Hungary Italy Netherlands Nether l a n d s

marked

*

E o i t o r i a l Committee:

Chairman:
Krochmann, J Vandermeersch M G Moore, J R Vermeulen, J Hengstberger, F Final editing: Billmeyer, F Germany, Fed. Rep. Belgium Great Britain Netherlands South Africa

USA

I V

CONTENTS

Page

1 TERMINOLOGY

.

......................................................

1

1.1 Q u a n t i t i e s

1.2

................................................... 1.1.1 Luminous i n t e n s i t y ..................................... 1.1.2 I l l u m i n a n c e ............................................ 1.1.3 Luminance .............................................. Luminous i n t e n s i t y d i s t r i b u t i o n body .........................

1

1 1 7 2

1 . 3 Luminous i n t e n s i t y d i s t r i b u t i o n c u r v e
1 . 4 I s o c a n d e l a diagram

........................ ...........................................

2
2

1.5 Measuring f i e l d and m e a s u r i n g - f i e l d a n g l e i n luminance mea-

1.6

.................................................... Terms for measuring i n s t r u m e n t s .............................. 1.6.1 Photometer .............................................
surements 1.6.2 Goniophotometer 1.6.3 Photometer head 1.6.4 Acceptance a r e a

2
3

3 3 3 3

........................................

........................................

........................................ 1 . 7 P h o t o m e t r i c c e n t r e ( o f a lamp or l u m i n a i r e ) .................. 1.8 S t r a y l i g h t .................................................. 1 . 9 L i m i t i n g p h o t o m e t r i c d i s t a n c e ............................... 2 . PRINCIPLES OF LUMINOUS INTENSITY MEASUREMENTS .................... 2.1 P h o t o m e t r i c d i s t a n c e law ..................................... 2 . 2 Luminance i n t e g r a t i o n ........................................ 3 . TYPES O PHOTOMETER HEADS ........................................ F
3 . 1 Photometer head f o r measuring i l l u m i n a n c e
3.2

4

4
4

4
4

6
6 6
7

..................... Photometer head f o r luminance i n t e g r a t i o n .................... 3 . 2 . 1 C o n s t r u c t i o n ........................................... 3.2.1.1 Photometer head w i t h l e n s ......................
V

7
7

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CIE 70 87

9006345 0003023 070

3.2.1.2 3.2.1.3

Photometer head w i t h p a r a l l e l o r i e n t e d o p t i c s Photometer head w i t h tubes

..

8

..................... 8 3.2.2 I n f l u e n c e o f inhomogeneous i l l u m i n a t i o n .............. 11 3.2.3 I n f l u e n c e o f t h e m e a s u r i n g - f i e l d angle ............... 12 4 . MEASURINC PLANES ................................................. 13 4 . 1 A-Planes .................................................... 13

.................................................... 14 4.3 C-Planes .................................................... 14 4.4 C o n i c a l s u r f a c e s ............................................ 16 4.5 Symbols f o r plane angles .................................... 16 4.6 R e l a t i o n s h i p s ............................................... 17 5 . GONIOPHOTOMETER WITH FACILITY FOR TURNING THE LIGHT SOURCE ....... 18
4.2 B-Planes

................................................... 5.2 A p p l i c a t i o n ................................................. 5.3 C o n s t r u c t i o n p r i n c i p l e s ..................................... 5.4 A u x i l i a r y d e t e c t o r s ......................................... 6 . GONIOPHOTOMETER WITH MOVING PHOTOMETER HEAD ...................... 6.1 P r i n c i p l e ................................................... 6.2 A p p l i c a t i o n ................................................. 6.3 C o n s t r u c t i o n P r i n c i p l e s ..................................... 7 . GONIOPHOTOMETER WITH R O T A T I N G MIRROR ............................. 7 . 1 P r i n c i p l e ................................................... 7.2 A p p l i c a t i o n ................................................. 7.3 C o n s t r u c t i o n p r i n c i p l e s ..................................... 8 . ANGLE MEASUREMENT ................................................
5.1
Principle

18 18 18 19 21

21

21
21

24

24
25
25
26

............................................... 8.2 Requirements ................................................ 9 . PHOTOELECTRONICS A D DATA PROCESSING ............................. N
8.1 Possibilities

26

27

27

VI

CIE 7 0 8 7 M 7006345 0003024 T O 7 M

10

. GENERAL
10.1
10.2

MEASURING C O N D I T I O N S

..................................... 28
28

10.3
10.4

....................................... Ageing ..................................................... Burning p o s i t i o n ...........................................
Operating c o n d i t i o n s Ambient temperature V i b r a t i o n and shock Stabilization period

29
29

10.5

........................................ ........................................

29
30

....................................... 30 10.7 E l e c t r i c a l measurements .................................... 30 30 10.7.1 Measurement u n c e r t a i n t y ............................. 10.7.2 Power t y p e and o p e r a t i n g mode ....................... 31 10.7.3 W i r i n g .............................................. 31 10.7.4 E x e c u t i o n o f t h e e l e c t r i c a l measurements ............ 31 10.7.5 Measuring c i r c u i t ................................... 31 10.8 B a l l a s t s ................................................... 32 10.9 Supply v o l t a g e ............................................. 32 10.10 E x e c u t i o n o f t h e measurements .............................. 32 1 . CORRECTION OF MEASUREMENT RESULTS ................................ 1 33 12 . PRESENTATION O RESULTS .......................................... F 33 1 3 . MECHANICAL ADJUSTMENT ............................................ 34
10.6
13.1 Goniophotorneter w i t h f a c i l i t y f o r t r a i n i n g t h e l i g h t source

. 34
35
35

13.2 Goniophotorneter with moving photometer head
13.3 Goniophotometer w i t h r o t a t i n g m i r r o r

.................

........................ 1 4 . CALIBRATION ...................................................... 14.1 Luminous i n t e n s i t y s t a n d a r d .................................
14.2 C a l i b r a t e d i l l u m i n a n c e meter

35
36

14.3 R e l a t i v e measurements
15

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........................... ......................................
V II

36
36

. ERROR

SOURCES AND MEASUREMENT ACCURACY

36

1 5 . 1 Mechanical arrangement

36

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CIE 70 87 I9006345 0003025 9 4 3

15.2 Angle measurements and a n g u l a r s t e p size

....................

37

15.3 I n f l u e n c e o f r o t a t i n g mirror o r photometer head f o r luminance

15.4

15.5

................................................. S t r a y l i g h t ................................................. R e l a t i v e s p e c t r a l r e s p o n s i v i t y ..............................
integration

37
38

39
39

15.6 I l l u m i n a n c e and luminance meter

15.7

15.8
15.9

............................. Data p r o c e s s i n g ............................................. L i m i t i n g photometric d i s t a n c e ............................... O p e r a t i n g c o n d i t i o n s ........................................

39
39 39
40

....................................... 16 . CHARACTERIZATION OF GONIOPHOTOMETERS ............................. 1 6 . 1 Mechanical arrangements ..................................... 16.2 Angle e n c o d i n g .............................................. 16.3 Photometer head ............................................. 16.4 P h o t o e l e c t r o n i c s and d a t a p r o c e s s i n g ........................ 17. LITERATURE .......................................................
15.10 Photometric s t a n d a r d

40

40 41
41

41

42

VI11

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CIE 70 87 I 9006345 0003026 B A T I

SUIMARY

T h i s t e c h n i c a l report c o n t a i n s t h e t e r m i n o l o g y r e q u i r e d f o r measurements o f luminous i n t e n s i t y d i s t r i b u t i o n s . I t a l s o summarizes t h e p r i n c i p l e s o f l u minous i n t e n s i t y measurements and t h e requirements f o r t h e p h o t o m e t e r h e a d s The c o o r d i n a t e systems u s e d f o r t h e meaemployed f o r such measurements. surement and r e p r e s e n t a t i o n of luminous i n t e n s i t y d i s t r i b u t i o n s are d e s cribed. The t y p e s o f g o n i o p h o t o m e t e r s , p o s s i b i l i t i e s f o r a n g l e e n c o d i n g , c h a r a c t e r i s t i c s o f t h e p h o t o - e l e c t r o n i c system and t h e a c q u i s i t i o n and p r o c e s s i n g o f t h e d a t a i n measurements of luminous i n t e n s i t y d i s t r i b u t i o n s are d i s c u s s e d i n d e t a i l . O t h e r s u b j e c t s c o v e r e d a r e t h e power s u p p l y , t h e meas u r i n g c o n d i t i o n s a n d t h e e x e c u t i o n , c o r r e c t i o n and r e p r e s e n t a t i o n o f l u m i n o u s i n t e n s i t y d i s t r i b u t i o n measurements. The v a r i o u s s e c t i o n s c o n t a i n s u f f i c i e n t d a t a on t h e r e q u i r e d c h a r a c t e r i z a t i o n o f g o n i o p h o t o m e t e r s . The r e p o r t is b a s e d mainly on t h e T e c h n i c a l R e p o r t o f C I E T e c h n i c a l Committee TC-2.2 on "Methods of c h a r a c t e r i z i n g t h e performance o f r a d i o m e t e r s a n d p h o t o m e t e r s [l] as w e l l a s on C I E p u b l i c a t i o n s 24 [ 2 ] , 2 7 [ 3 ] and 43 [ 4 ] . The t e r m i n o l o g y is l a r g e l y b a s e d on t h e I n t e r n a t i o n a l L i g h t i n g V o c a b u l a r y

PI
LA MESURE DES DISTRIBUTIONS D'INTENSITE LUMINEUSE ABSOLUE

Ce r a p p o r t t e c h n i q u e c o n t i e n t l a t e r m i n o l o g i e n é c e s s a i r e pour l a mesure d e s d i s t r i b u t i o n s d ' i n t e n s i t é lumineuse. 11 résume a u s s i les p r i n c i p e s d e mes u r e de l ' i n t e n s i t é l u m i n e u s e et les q u a l i t é s r e q u i s e s p o u r l a tete photoLes systémes de c o o r d o n n é e s m é t r i q u e u t i l i s é e p o u r d e telles mesures. u t i l i s é s pour l a mesure e t l a r e p r g s e n t a t i o n d e s d i s t r i b u t i o n s d ' i n t e n s i t é lumineuse s o n t d é c r i t s . Les types de g o n i o p h o t o m è t r e , l e s p o s s i b i l i t é s d e h r e p é r a g e a n g u l a i r e , l e s c a r a c t é r i s t i q u e s c system é l e c t r o n i q u e e t c e l l e s
d e l ' a c q u i s i t i o n e t du t r a i t e m e n t d e s données d a n s les measures d e d i s t r i b u t i o n d e l ' i n t e n s i t é l u m i n e u s e s o n t d é c r i t e s e n d é t a i l . Les a u t r e s s u j e t s t r a i t é s s o n t l ' a l i m e n t a t i o n é l e c t r i q u e , les c o n d i t i o n s de mesures e t l e u r e x é c u t i o n , l a c o r r e c t i o n e t l a r e p r é s e n t a t i o n des mesures d e d i s t r i b u t i o n Les d i f f é r e n t e s s e c t i o n s c o n t i e n e n t d e s données d' i n t e n s i t é lumineuse. s u f f i s a n t e s sur les c a r a c t é r i s t i q u e s r e q u i s e s pour les g o n i o p h o t o m è t r e s .

C r a p p o r t s ' a p p u y e p r i n c i p a l e m e n t s u r l e r a p p o r t t e c h n i q u e du c o m i t é teche n i q u e 2.2 de l a C I E "Methods of c h a r a c t e r i z i n g t h e p e r f o r m a n c e o f r a d i o meters and p h o t o m e t e r s " [i] a i n s i que s u r les p u b l i c a t i o n s CIE no 24 [Z], 27 [ 3 1 , e t 43 [4]. La t e r m i n o l o g i e est l a r g e m e n t empruntée au V o c a b u l a i r e I n t e r n a t i o n a l de 1'E c l a i r a g e [ 51.

IX

9006245 0003027 716 I

ZUCANENFASSUNG

D I E MESSUNG DER ABSOLUT EN L ICH T s T ?RK E VER TE I UNG L
D i e s e r Technische B e r i c h t enthalt zun?chst d i e für Lichtstarkemessungen w i c h t i g e n ?egriffsbectimmungen. Danach werden d i e P r i n z i p i e n der L i c h t st?rkemessung und 4ngaben ?ber d i e dementsprechend zu verwendenden Photometerk?pfe zusammengestellt. D i e f ü r d i e Messung und D a r s t e l l u n g d e r L i c h t s t ? r k e v e r t e i l i J n g verwendeten Ebenensysteme werden angegeben. ?esond i e M ? g l i c h k e i t e n der ders werden d i e Arten von Goniophotometern, Winkelerfassung, Aussagen ?ber d i e P h o t o e l e k t r o n i k und d i e R e g i s t r i e r u n g und Datenverarbeitung b e i der Messung der L i c h t s t ? r k e v e r t e i l u n g behandelt. Auch Aussagen zur Spannungcversorgung, ZU den t ? k bedingungsn und z u r Durchführung, K o r r e k t u r und D a r s t e l l u n g der L i c h t s tgrkemessungen werden gemacht. R e i den e i n z e l n e n K a p i t e l n werden ausreichende Angaben ?ber d i e notwendige Kennzeichnung von Goniophotometern a u f g e f ü h r t .

Dieser ? e r i c h t s t ü t z t s i c h vor a l l e m a u f den Technischen B e r i c h t des CIE Technischen Komi t e e s TC-2.2 "Me thocis o f c h a r a c t er i z i n g t h e p e r f ormance of radiometers and photometers" [ 11 sowie auf d i e CIE-Publicationen No. 24 [21, Wo. 27 [ 3 ] , und No. 43 141. R e i den Begriffsbestimmungen s i n d d i e ilngaben des I n t e r n a t i o n a l e n W?rterbuchs der L i c h t t e c h n i k [ 51 weitgehend zugrunde gelegt.

X

CIE 70 8 7

900bL45 0003028 6 5 2

I. TERMINOLOGY

1.1

QUANTITIES r 5 l

1.1.1 LUMINOUS I N T E N S I T Y
The luminous i n t e n s i t y I (of a source i n a g i v e n d i r e c t i o n ) q u o t i e n t o f t h e luminous f l u x d@ l e a v i n g t h e source, propagated i n

is t h e an ele-

ment o f s o l i d angle c o n t a i n i n g t h e g i v e n d i r e c t i o n , angle Cn.

by t h e element o f s o l i d

Symbol:
Unit
:

I,Iv
Candela (symbol: cd)

1.1.2

ILLUMINANCE

The i l l u m i n a n c e E a t a p o i n t of a s u r f a c e is t h e q u o t i e n t o f t h e luminous f l u x d$ i n c i d e n t on an element o f t h e s u r f a c e d c a n t a i n i n g t h e A p o i n t , by t h e area o f t h a t element.

Symbol: Unit :

E,,
Lux (symbol:

1x1

1.1.3

LUMINANCE

The luminance L ( i n a g i v e n d i r e c t i o n , a t a p o i n t on t h e s u r f a c e of a source or a receptor, or a t a p o i n t i n t h e path of a beam) is t h e quot i e n t o f t h e luminous f l u x ,

d*@; l e a v i n g , a r r i v i n g a t , or passing through

an element of s u r f a c e d a t this p o i n t and propagated i n d i r e c t i o n s d e f i n e d A by an elementary cone d;l c o n t a i n i n g t h e g i v e n d i r e c t i o n , by t h e product of t h e s o l i d angle of t h e cone and t h e area o f t h e o r t h o g o n a l p r o j e c t i o n of t h e element o f s u r f a c e on a plane p e r p e n d i c u l a r t o t h e g i v e n d i r e c t i o n .

L =
$2
E

d2 Q dA

COSE

Angle between considered
:

the

normal

to

the

area

and

the

direction

Symbol:
Unit

L,L, Candela per s q u a r e meter (symbol: cd*rn-2)

1

1.2

SURFACE OF LUMINOUS INTENSITY D I S T R I B U T I O N
The surface o f

luminous i n t e n s i t y d i s t r i b u t i o n is t h e surface formed

by t h e extremities o f a l l t h e r a d i u s v e c t o r s drawn from a common o r i g i n ,

t h e l e n g t h o f each r a d i u s v e c t o r b e i n g p r o p o r t i o n a l t o t h e luminous i n t e n s i t y of t h e s o u r c e i n t h e c o r r e s p o n d i n g d i r e c t i o n .

1.3

LUMINOUS INTENSITY D I S T R I B U T I O N CURVE

The IiJminous i n t e n s i t y d i s t r i b u t i o n c u r v e ( f o r a lamp or l i g h t f i t t i n g ) i s t h e c u r v e , g e n e r a l l y p o l a r , which r e p r e s e n t s t h e luminous i n t e n s i t y i n a p l a n e p a s s i n g t h r o u g h t h e s o u r c e , as a f u n c t i o n o f t h e a n g l e measured from soine g i v e n d i r e c t i o n .

Note : a ) When t h e p l a n e is b) When t h e downward s o u r c e h a s a symmetrical luminous i n t e n s i t y d i s t r i b u t i o n , t h e g e n e r a l l y a meridian plane. r e f e r e n c e d i r e c t i o n is v e r t i c a l , a n g l e s a r e measured f r o m t h e

vertical.

1.4

ISOCANDELA DIAGRAM

The i s o c a n d e l a diagram is t h e a r r a y o f i s o c a n d e l a c u r v e s . These are curves t r a c e d on an imaginary s p h e r e w i t h t h e s o u r c e a t its c e n t r e and j o i n i n g a l l t h e p o i n t s c o r r e s p o n d i n g t o t h o s e d i r e c t i o n s i n which t h e l u m i nous i n t e n s i t y is t h e same, or a plane p r o j e c t i o n o f t h i s curve.

1.5

MEASURING F I E L D AND MEASURING-FIELD ANGLE I N LUMINANCE MEASUREMENTS[ 61

The measuring f i e l d of a luminance meter is t h e t o t a l i t y of a l l p o i n t s i n t h e external s p a c e t h a t r a d i a t e i n t o t h e a c c e p t a n c e area and a r e s e n s e d by t h e d e t e c t o r and e v a l u a t e d by i t w i t h a d i r e c t i o n - d e p e n d e n t r e s p o n s i v i t y o f a t l e a s t 10% of t h e maximum r e s p o n s i v i t y . Note:
The measuring f i e l d is u s u a l l y c i r c u l a r .

a r e a l s o p o s s i h l e , however ( e . g . ,

O t h e r f i x e d or v a r i a b l e s h a p e s trapezoidal, rectangular, quadratic)

The m e e s u r i n g - f i e l d e n g l e tr is t h e a n g l e under which t h e measuring f i e l d a p p e a r s when viewed from t h e measuring p l a n e .

2

1.6

TERMS FOR MEASURING INSTRUMENTS

1.6.1

PHOTOMETER
A photometer i s an i n s t r u m e n t f o r t h e measurement o f p h o t o m e t r i c

quantities.

Note: P h o t o m e t r i c q u a n t i t i e s are q u a n t i t i e s t h a t c a n be d e r i v e d from r a d i o m e t r i c q u a n t i t i e s by means o f c e r t a i n c o n v e n t i o n s ( l a w o f a d d i t i v i t y , V ( X ) f u n c t i o n , d e f i n i t i o n o f t h e u n i t o f luminous i n t e n s i t y )

Dl
1.6.2

GONIOPHOTOMETER
A goniophotometer is a p h o t o m e t e r for t h e measurement o f t h e a n g u l a r

dependence o f a p h o t o m e t r i c q u a n t i t y . Note:
A goniophotometer f o r t h e measurement of t h e s p a t i a l luminous i n t e n s i t y

distribution photometer.

is

also

called

a

luminous

intensity

distribution

A goniophotometer f o r t h e measurement o f t h e s p a t i a l luminous i n t e n s i t y d i s t r i b u t i o n u s u a l l y c o n s i s t s o f a m e c h a n i c a l d e v i c e f o r t h e s u p p o r t and p o s i t i o n i n g o f t h e l i g h t s o u r c e and t h e photometer head and one ( o r more) o f t e n moveable - photometer h e a d s t o g e t h e r w i t h t h e necessary t r a n s d u c e r s and r e a d o u t s as well as d e v i c e s f o r a c q u i r i n g and p r o c e s s i n g d a t a .

1.6.3

PHOTOMETER HEAD

A photometer head c o n s i s t s o f a l i g h t - s e n s i t i v e d e t e c t o r and f a c i l i t i e s f o r t h e s p e c t r a l e v a l u a t i o n (e.g., c o l o u r f i l t e r s ) or f o r t h e s p e c t r a l dispersion (e.g., gratings) o f the light. I t may a l s o c o n t a i n f a c i l i t i e s f o r t h e d i r e c t i o n a l e v a l u a t i o n o f t h e l i g h t , e . g . , d i f f u s i n g windows, l e n ses, apertures. The l i g h t - s e n s i t i v e d e t e c t o r c o n v e r t s t h e i n c i d e n t l i g h t i n t o an e l e c t r i c a l q u a n t i t y . 1.6.4

ACCEPTANCE AREA

T h e a c c e p t a n c e a r e a i s t h e area o f t h e photometer head which is rec e i v i n g and d i r e c t i o n a l l y e v a l u a t i n g t h e i n c i d e n t l i g h t .

3

-~

-

CIE 70 8 7 I7006345 0003033 147

1.7

PHOTOMETRIC CENTRE (OF A LAMP OR L U M I N A I R E )
The p h o t o m e t r i c c e n t r e o f a lamp o r l u m i n a i r e is t h e r e f e r e n c e p o i n t

from which t h e p h o t o m e t r i c d i s t a n c e law is a p p l i c a b l e ( s e e section 2 . 1 ) . F o r lamps t h e p h o t o m e t r i c c e n t r e c o r r e s p o n d s t o t h e c e n t r e o f g r a v i t y o f t h e light-emitting area. F o r lamps w i t h r e f l e c t o r s t h e p h o t o m e t r i c c e n t r e i s s i t u a t e d a t t h e c e n t r e o f t h e exit aperture. F o r l u m i n a i r e s data a b o u t t h e p h o t o m e t r i c c e n t r e a r e c c n t a i n e d i n t h e T e c h n i c a l Report "Photometry of Luminaires" [ 81. Yote:
For

t h e measurement o f t h e luminous i n t e n s i t y d i s t r i b u t i o n t h e photometric c e n t r e o f t h e l i g h t s o u r c e s h o u l d l i e on t h e c r o s s p o i n t of t h e a x e s o f th e goniophotometer.
STRAY L I G H T -

1.8

S t r a y l i g h t is t h e p a r t o f t h e luminous f l u x i n c i d e n t on and e v a l u a t e d by t h e photometer head t h a t does n o t r e a c h t h e measuring a r e a of t h e photom e t e r head i n a d i r e c t l i n e froin t h e l i g h t s o u r c e .
1.9

L L M I T I N G PHOTOMETRIC D I--T A N C E S

The l i m i t i n g p h o t o m e t r i c d i s t a n c e is t h e a l l o w e d minimum d i s t a n c e between Light source and photometer head, For which t h e measuring e r r o r i s smaller t h a n t h e p e r m i t t e d e r r o r .

2. PRINCIPLES O LWINOUS INTENSITY MEASUREMENTS F

Luminous i n t e n s i t i e s can be measured v i a a measurement of the i l l u m i n a n c e and c a l c u l a t i o n v i a t h e p h o t o m e t r i c d i s t a n c e law, or by i n t e g r a t i o n of t h e luminance. Both p o s s i b i l i t i e s f o l l o w from t h e b a s i c law of photometry.
2.1
PHOTOMETRIC -DISTANCE LAW

The p h o t o m e t r i c d i s t a n c e lavJ allows one t o d e t e r m i n e t h e luminous i n t e n s i t y according t o

I
I
E

E

r2 / ( c o s 2

80)

(4)

r
E2

QO

Luminous i n t e n s i t y i n t h e d i r e c t i o n t o t h e a c c e p t a n c e a r e s I l l u m i n a n c e on t h e a c c e p t a n c e a r e a D i s t a n c e between l i g h t s o u r c e and a c c e p t a n c e a r e a Angle o f i n c i d e n c e , measured r e l a t i v e t o t h e normal t o t h e acceptance a r e a Isr (unit s o l i d angle)

4

CIE 7 0 87

?OObLLt5 0003032 O ? 3

T h e q u a n t i t y 80 i s u s e d i n a c c o r d a n c e w i t h t h e f o u r t h e d i t i o n of t h e C I E vocabulary ( i n p r e p a r a t i o n ) , which p e r m i t s its o p t i o n a l u s e . There i s no complete agreement on t h e need t o use 8 0 , which may e q u a l l y well be o m i t t e d or r e p l a c e d by t h e number 1.

The Equation (4) only a p p l i e s f o r d i s t a n c e s r t h a t exceed t h e l i m i t i n g photometric d i s t a n c e . measuring e r r o r depends on:

-

-

t h e l a r g e s t dimension of t h e l i g h t s o u r c e t h e s p a t i a l and d i r e c t i o n a l luminance d i s t r i b u t i o n o f t h e l i g h t s o u r c e t h e s p a t i a l and d i r e c t i o n a l r e s p o n s i v i t y of t h e a c c e p t a n c e area of the photometer head.

Yote 1:
F o r a c i r c u l a r e m i t t i n g a r e a w i t h c o n s t a n t luminance ( l a m b e r t i a n r a d i a t o r ) and a c i r c u l a r r e c e i v i n g a r e a t h e l i m i t i n g p h o t o m e t r i c d i s t a n c e r is t a k e n a s 10 times (5 times) t h e d i a m e t e r o f ' t h e l a r g e r o f t h e two a r e a s . I n t h i s case t h e e r r o r o f I i n t h e d i r e c t i o n o f t h e a x i s o f t h e d i s k i n t h e c a l c u l a t i o n a c c o r d i n g t o t h e p h o t o m e t r i c d i s t a n c e law is less than 0,5 X (1 X).

Note 2:
For narrow luminous

intensity distributions the limiting photometric d i s t a n c e is g r e a t e r t h a n f o r a Lambertian r a d i a t o r [ 9,101.

Note 3: When c a l c u l a t i n g t h e luminous i n t e n s i t y a c c o r d i n g t o e q u a t i o n (4) it s h o u l d be a s c e r t a i n e d , i f n e c e s s a r y by means of measurements a t d i f f e r e n t d i s t a n c e s , whether t h e l i m i t i n g p h o t o m e t r i c d i s t a n c e is exceeded. For goniophotometers w i t h s t a t i o n a r y photometer heads f o r which t h e measuring d i s t a n c e i s smaller t h a n t h e l i m i t i n g p h o t o m e t r i c d i s t a n c e , t h e measuring d i s t a n c e can b e extended by t h e u s e of a s u f f i c i e n t l y l a r g e d e f l e c t i n g mirror. The p o l a r i z a t i o n o f t h e l i g h t by t h e d e f l e c t i n g m i r r o r a s well as t h e s p e c t r a l r e f l e c t a n c e of t h e d e f l e c t i n g m i r r o r must be t a k e n i n t o a c c o u n t . Note 4: When t h e luminous i n t e n s i t y i s d e r i v e d a c c o r d i n g t o e q u a t i o n (4) i t is i m p o r t a n t t o l i m i t t h e i n c i d e n c e of s t r a y l i g h t on t h e photometer head by means o f b a f f l e s between t h e l i g h t s o u r c e and t h e photometer head.

5

411 p a r t s o f t h e background o f t h e l i g h t s o u r c e t h a t a r e v i s i b l e f r o m t h e measuring a r e a of t h e photometer h e a d s h o u l d b e a s black a s p o s s i b l e
(113. 4 large a d i s t a n c e a s p o s s i b l e s h o u l d be k e p t between t h e l i g h t s s o u r c e and t h e background ( F i g . I) ..

BAFFLES / / \

BACKGROUND

BLACK

LIGHT SOURCE
Fig. 1

I

Reduction o f s t r a y l i g h t i n luminous i n t e n s i t y measurements

2.2

LUMINANCE I N T E G R A T I O N

Luminous i n t e n s i t y c a n be determined by means o f luminance i n t e g r a -

tion :
cos 1

(5)

Al dA l Lk1)
1

emitting area element o f t h e e m i t t i n g a r e a luminance o f t h e a r e a element dA, i n t h e d i r e c t i o n i n which t h e luminous i n t e n s i t y i s t o be determined e m i t t i n g a n g l e o f t h e a r e a element dA, between its a r e a normal and t h e d i r e c t i o n f o r which t h e luminous i n t e n s i t y i s t o be determined.

3, TYPES O PHOTOMETER HEADS F
Depending on t h e t h e o r e t i c a l r e l a t i o n s h i p used f o r t h e d e t e r m i n a t i o n o f t h e luminous i n t e n s i t y ( e q u a t i o n ( 4 ) o r ( 5 ) ) , t h e r e a r e two t y p e s o f photometer h e a d s i n use in goniophotometers.

3.1

PHOTOMETER HEAD FOR MEASURING

ILLUMINANCE

For t h e d e t e r m i n a t i o n o f t h e luminous i n t e n s i t y a c c o r d i n g t o e q u a t i o n ( 4 ) a photometer head f o r t h e measurement o f illuminance m u s t be employed. Such a photometer head m u s t comply with t h e f o l l o w i n g r e q u i r e m e n t s [ 1,6] :
6

-

-

good f i t of t h e r e l a t i v e s p e c t r a l r e s p o n s i v i t y t o t h e V h ) f u n c t i o n (error fi 1 linearity (error f 3 ) l o w f a t i g u e ( e r r o r f5 1 independence from t h e ambient t e m p e r a t u r e ( t e m p e r a t u r e c o e f f i c i e n t a ) a s small a s o l i d a n g l e a s p o s s i b l e f o r t h e a c c e p t a n c e a r e a of t h e photometer head a s seen froin t h e p h o t o m e t r i c c e n t r e .

The terminology f o r t h e errors f i t o f 5 and a c l a s s i f i c a t i o n of i l l u m i n a n c e meters have been compiled by t h e C I E [ 6 ] 3.2 3.2.1 3.2.1.1

PHOTOMETER HEAD FOR LUMINANCE INTEGRATION
CDNSTRUCTION Photometer head w i t h lens [U]

A photometer head f o r luminance i n t e g r a t i o n by means o f a l e n s c o n s i s t s o f a l e n s w i t h a d i a m e t e r l a r g e r t h a n t h e l i g h t s o u r c e and a det e c t o r ( i n c l u d i n g f i l t e r f o r V ( h ) c o r r e c t i o n ) t h a t is p o s i t i o n e d behind a diaphragm a t t h e f o c a l p o i n t o f t h e l e n s ( a l s o c a l l e d t h e f i e l d s t o p ) ( F i g . 2 ) . The measuring f i e l d a n g l e a of such a photometer head is
a

= 2

arc tan (a/?f)

(61

f

a

f o c a l l e n g t h of l e n s d i a m e t e r of m e a s u r i n g - f i e l d

stop

UGHT %URCE
L

I

~-------- - - - --,--,

ACCEPTANCE AREA OR APERTURE (DIAMETER a )

9

r L

f

4

F i g . 2:

Photometer head w i t h lens f o r luminous i n t e n s i t y measurements by means o f luminance i n t e g r a t i o n

The l a r g e s t diameter D o f a l i g h t s o u r c e t h a t can be measured w i t h a photometer head f o r luminance i n t e g r a t i o n by means o f a l e n s is given by
D
D

d

-

r

9

a/f

(71

d r

l a r g e s t p e r m i s s i b l e e x t e n t of t h e l i g h t source diameter of t h e l e n s distance between l e n s and l i g h t s o u r c e

7

~

CIE 70 8 7
The neasurements

9006345 0003035 8 9 2 I

can be made a t an a r b i t r a r y d i s t a n c e r between l i g h t s o u r c e and l e n s as long as t h e c o n d i t i o n a c c o r d i n g t o e q u a t i o n ( 7 ) and conditions regarding t h e limiting photometric distance ( l i m i t i n g t h e r a t i o ?/r t o a maximum v a l u e ) are s a t i s f i e d (see a l s o 3 . 2 . 3 ) .
3.2.1.2

Photometer head w i t h p a r a l l e l o r i e n t e d o p t i c s

I n s t e a d o f a s i n g l e l e n s i t is a l s o p o s s i b l e to use s e v e r a l lens e s t h a t are p o s i t i o n e d immediately n e x t t o each o t h e r . By means of s u c h EI^ arrangement i t is p o s s i b l e t o measure l i g h t s o u r c e s with l a r g e r e m i t t i n g areas.

A photometer head w i t h p a r a l l e l o r i e n t e d lenses can a l s o be c o n s t r u c t e d i n such a way t h a t t h e lenses are merely p o s i t i o n e d next t o each o t h e r i n a s i n g i e l i n e . T h i s row of l e n s e s can be moved or t i l t e d i n a p l a n e

iiormal t o t h e measuring d i r e c t i o n , and t h e luminance i n t e g r a t i o n (summat i o n ) p e r p e n d i c u l a r t o t h e row of lenses must be performed n u m e r i c a l l y

[131.
3.2.1.3 Photometer head w i t h t u b e s [14,151

A photometer head f o r luminance i n t e g r a t i o n can also be c o n s t r u c t e d by means of p a r a l l e l t u b e s followed by a l i g h t c o l l e c t i n g d e v i c e and a p h o t o - e l e c t r i c d e t e c t o r (with V ( h ) response). Figure 3 shows such an arrangement, i n which t h e l i g h t - c o l l e c t i n g d e v i c e is r e a l i z e d by means of a s p h e r i c a l d e v i c e l o c a t e d behind t h e t u b e s and w i t h an e f f e c t similar t o an i n t e g r a t i n g s p h e r e . The d e t e c t o r can be l o c a t e d a t t h e s i d e of t h e s p h e r i A s p a t i a l l y c o n s t a n t e v a l u a t i o n of the luminance can be c a l device. a c h i e v e d by means of a p e r t u r e s i n f r o n t o f t h e d e t e c t o r .

-

I
I

Il ’

r
Jig. 3 :

I

II I

lili I I Il! I
I

PHOTOMULTIPUER CAP OFTHE SPHERE
Photometer head w i t h t u b e s f o r luminance i n t e g r a t i o n
8

CIE 7 0 87

900b145 O003036 7 2 9 I

The r e l a t i v e s p e c t r a l r e s p o n s i v i t y o f such a photometer head is d e t e r m i n e d d e c i s i v e l y by t h e s p e c t r a l r e f l e c t a n c e o f t h e i n t e r i o r p a i n t of t h e spherical c o l l e c t i n g device. P o l l u t i o n o f t h e p a i n t - even if i t is n o n - s e l e c t i v e - c a n l e a d t o a change i n t h e r e l a t i v e s p e c t r a l r e s p o n s i v i t y and i n the a b s o l u t e r e s p o n s i v i t y o f t h e d e v i c e a s a whole. Note:
A test o f t h e r e l a t i v e s p e c t r a l r e s p o n s i v i t y of t h e whole measuring head

is n o t p o s s i b l e i n p r a c t i c e .
Figure 4 shows a n o t h e r arrangement o f t h e photometer head with p a r a l l e l o r i e n t e d t u b e s , f o r which a h i g h u n i f o r m i t y o f t h e s p a t i a l r e s p o n s i v i t y c a n
be a c h i e v e d and which h a s a s t a b l e and measurable s p e c t r a l r e s p o n s i v i t y

[ 161
TUBES

HOUSING

'DETECTOR
F i g 4: Photometer head f o r luminance i n t e g r a t i o n
The d i s t a n c e between t h e l i g h t s o u r c e and t h e a c c e p t a n c e a r e a o f t h e photo-

meter head can i n f l u e n c e t h e r e s u l t o f t h e measurement.

I n order completely t o c o v e r t h e e m i t t i n g a r e a o f a l i g h t s o u r c e , t h e smallest d i s t a n c e rmin between the a c c e p t a n c e a r e a and t h e l i g h t source s h o u l d comply with ( F i g . 5 )
min where

R
d
f

d i s t a n c e between a d j a c e n t tubes i n tube p l a t e tube diameter thickness o f t u b e plate 9

CIE 7 0 157

9006345 0003037 665

For mechanical r e a s o n s , r,,-,in must a l s o exceed h a l f o f t h e l a r g e s t e x t e n t c ) of t h e Light s o u r c e . Thus a c o n s e r v a t i v e l i m i t f o r t h e l a r g e s t diinen9 s i o n (Dma,! o f t h e l a r g e s t l i g h t source t h a t may be measured w i t h t h e i n s t r u m e n t would be set by r e q u i r i n g the sum of rmin and Dmax/2 t o e q u a l t h e f i x e d r a d i u s o f r o t a t i o n ( r ) o f t h e goniophotometer. From t h i s condit i o n ilmax be s p e c i f i e d a s can

Dmax

rinin
P

l a r g e s t extent o f t h e l a r g e s t permissible l i g h t source according t o equation (8) g i v e n r a d i u s o f r o t a t i o n f o r a p a r t i c u l a r goniophotometer

LIGHT EMITTING AREA

HORIZONTAL PROJECTION

TUBE-PUE

VERTICAL PR03ECTION

O
F i g . 5:

i

Dimensions f o r photometer head f o r luminance i n t e g r a t i o n w i t h tube p l a t e

CIE 70 87 M 7006345 0003038 5 T L I

T h e minimum diameter 6 o f t h e acceptance area of t h e photometer head should

be

I t should be a s c e r t a i n e d whether t h e r e s u l t i s independent o f t h e d i s t a n c e between l i g h t source and acceptance area.

3.2.2

INFLUENCE OF INHOMOGENEOUS

ILLUMINATION [ 2,3,15]

A s p a t i a l l y inhomogeneous luminance o f t h e l i g h t source can cause measuring e r r o r s , i f t h e r e s p o n s i v i t y o f t h e photometer head i s n o t u n i f o r m over t h e
acceptance area.

The measuring e r r o r w i l l depend on t h e luminance d i s t r i b u t i o n o f t h e l i g h t source, t h e s i z e o f t h e source and t h e magnitude and d i s t r i b u t i o n o f
responsivity differences

over t h e acceptance area.

I f a c a l i b r a t i o n i s performed, t h e measuring e r r o r w i l l depend on t h e r e l a tive p r o p e r t i e s o f t h e c a l i b r a t i o n source and t h e source t o be measured as well as on t h e p o s i t i o n o f t h e sources r e l a t i v e t o t h e acceptance area.

I f p o s s i b l e t h e c a l i b r a t i o n source and t h e source t o be measured s h o u l d be p l a c e d i n t h e same p o s i t i o n .
To p r o v i d e a b a s i s f o r

t h e e v a l u a t i o n o f p o s s i b l e measuring e r r o r s t h e r e s p o n s i v i t y d i s t r i b u t i o n over t h e acceptance area should be determined.

This may be done by b r i n g i n g t h e photometer head t o a h o r i z o n t a l p o s i t i o n with t h e normal t o t h e acceptance area p o i n t i n g upwards and moving a l i g h t source i n a h o r i z o n t a l p l a n e a t a d i s t a n c e g r e a t e r than t h e m i n i m u m d i s tance rmin (see e q u a t i o n 8) i n such a way t h a t i t covers s u c c e s s i v e l y t h e whole area above t h e photometer head.
T h e l i g h t source s h o u l d have an a p p r o x i m a t e l y constant luminous i n t e n s i t y d i s t r i b u t i o n i n d i r e c t i o n s c l o s e t o t h e normal and i t s e m i t t i n g area s h o u l d n o t exceed 1/10 o f t h e acceptance area or 10 cm2 (whichever i s s m a l l e r ) . A

100 W f r o s t e d incandescent lamp may be used.
The readings o f t h e photometer f o r t h e v a r i o u s p o s i t i o n s o f t h e lamp may be

used t o c a l c u l a t e t h e e r r o r f g by inhomegeneous i l l u m i n a t i o n r e l e v a n t t o t h e intended use o f t h e photometer.

A worst-case e r r o r is o b t a i n e d i f f g i s determined as t h e l a r g e s t percentage d i f f e r e n c e between readings.

11

CIE 70 87

9 0 0 b L 4 5 0003039 438 H

Y

Yvax

minimum r e a d i n g maximum r e a d i n g

photometer is t o be used f o r t h e measurement o f compact l i g h t sources, fg s h o u l d he determiiieá a s t h e l s r g e s t p e r c e n t a g e d i f f e r e n c e of ,s:i t h e mean o f t h e r e a d i n g s t a k e n a l o n g t h e c i r c u m f e r e n c e of any c i r c l e coritained w i t h i n t h e a c c e p t a n c e a r e a and c e n t r e d on t h e midpoint of' t h e 8 i - w and ( b ) t h e midpoint reading
the

If

YO

nii

d po i n t r e a d i n g

Au

(1 Y,),,,

! I

Y,),i,

a n g u l a r step size of r e a d i n g s i n d e g r e e s maximum o f t h e mean r e a d i n g a l o n g a c i r c l e minimum o f t h e mean r e a d i n g along a c i r c l e

I f t h e photometer i s t o be u s e d f o r t h e measurement o f Linear L i g h t s o u r c e s , f g s h o u l d be determined a s the l a r g e s t p e r c e n t a g e d i f f e r e n c e o f t h e mean r e a d i n g a l o n g any d i a m e t e r s o f t h e circles and t h e mean r e a d i n g a l o n g t h e c i r c l e diameter parallel t o t h e h o r i z o n t a l a x i s o f t h e photometsr.

I f t h e p h o t o m e t e r i s to be used f o r b o t h compact and Linear l i g h t sources t h e l a r g e r o f t h e above e r r o r s s h o u l d be s t a t e d .
Readings s h o u l d be taken a t t h e m a l l e s t p o s s i b l e i n c r e m e n t s i n circle diameters and a n g u l a r d i s t a n c e between d i a m e t e r s . in t h e d e t e r m i n a t i o n of fg p e r c e n t a g e d i f f e r e n c e s f o r i n c r e m e n t s o f circle d i a m e t e r s o f 20 cm and inc r e m e n t s o f a n g u l a r d i s t a n c e of 5 o s h o u l d be c a l c u l a t e d .
3 +Z. 3

INFI-IJENCE O THE MEASURING-FIELD ANGLE F

When t h e luminous i n t e n s i t y is determined by an i l l u m i n a n c e measurem e n t t h e limiting photometric d i s t a n c e r d e t e r m i n e s a maximum v a l u e f o r t h e r a t i o D/r (D b e i n g t h e l a r g e s t e x t e n t o f t h e l i g h t source). T h i s l i m i t i n g r a t i o m i x t a l s o be taken i n t o a c c o u n t i f t h e luminous i n t e n s i t y is d e t e r m i n e d v i a a h m i n a n c e measiiretnent. F o r a photometer head w i t h l e n s t h i s means

-<

t4easuring-field

angle according t o equation ( 6 )

12

CIE 70 87

9006145 0003040 1 5 T I

For a photometer head w i t h t u b e s i t r e q u i r e s
d/f

2 D/r

d , f see F i g . 5

4 MEASURING PLANE [ 2,3,4,17] .
I n g e n e r a l the luminous i n t e n s i t y d i s t r i b u t i o n o f l i g h t sources ( l a m p s o r l u m i n a i r e s ) i s measured i n a number o f p l a n e s . The number o f luminous i n t e n s i t y d i s t r i b u t i o n c u r v e s and t h e s e l e c t i o n o f measuring p l a n e s depend on t h e k i n d o f l i g h t source a n d i t s u s e as well a s OR t h e t y p e o f goniophotometer. From t h e v a r i e t y o f p o s s i b l e measuring p l a n e s t h r e e s y s t e m s o f p l a n e s have proven s p e c i a l l y u s e f u l .

4.1

A-PLANES ( S e e F i g . 6)

The t o t a l i t y o f A-planes is t h e group o f p l a n e s f o r which t h e l i n e of i n t e r s e c t i o n goes through t h e photometric c e n t r e p a r a l l e l t o t h e emitting area and p e r p e n d i c u l a r t o t h e assumed a x i s o f t h e l i g h t s o u r c e .

Note:
The system o f A-planes i s c o u p l e d r i g i d l y t o t h e l i g h t s o u r c e and f o l lows i t s t i l t i f t h e l i g h t source is t i l t e d .

LINE OF INTERSECTION

Fig. 6:

A-planes
73

CIE i 0 87
4.2

9006345 0003041 096

B-PLBNEC

(See F i g . 71

The t o t a l i t y of B-planes is t h e group o f p l a n e s f o r which the l i n e o f i n t e r s e c t i o n goes t h r o u g h t h e p h o t o m e t r i c c e n t r e and is parallel t o t h e assumed a x i s o f t h e l i g h t source and i s p e r p e n d i c u l a r t o t h e l i n e o f i n t e r s e c t i o n o f t h e A-planes. Note : The system of B-planes is coupled r i g i d l y t o t h e l i g h t source and f o l lows its t i l t i f t h e light source is t i l t e d .

LINE OF INTERSECTION AND 'AXIS OF LIGHT SOURCE

Fig. 7:

6-planes

4.3

C-PLANES

(See Fig. 8 )

The t o t a l i t y of C-planes is t h e group o f p l a n e s Por which t h e l i n e o f

i n t e r s e c t i o n is t h e v e r t i c a l l i n e through t h e p h o t o m e t r i c c e n t r e . Wote : The system o f C-planes is g e n e r a l l y o r i e n t e d r i g i d l y i n space and does n o t follow 8 t i l t i n t h e l i g h t s o u r c e . The l i n e o f i n t e r s e c t i o n of Cp l a n e s is o n l y p e r p e n d i c u l a r t o t h e l i n e s o f i n t e r s e c t i o n of t h e A- and 8-planes f o r zero t i l t (6 = O) o f t h e l i g h t s o u r c e .

I n some c a s e 5 t h e t o t a l i t y o f C-planes is also referred t o a s t h e group of pLanes whose l i n e o f i n t e r s e c t i o n is t h e l i n e o f i n t e r s e c t i o n of A o - and Bo-planes ( s e e F i g . 9 ) . I n t h a t cace t h e system o f C-planes is a l s o r i g i d l y c o u p l e d t o the l i g h t source (as is t h e case f o r t h e A- and ? - p l a n e s ) .
14

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CIE 70 87

900bL45 00030Y2 T22 I

AXIS

SOURCE

OF LIGHT

‘270

(PERPENDICULAR TO MEASURING PLANES)

F i g . 8:

C-planes (6 t i l t a n g l e o f l u m i n a i r e )

LINE OF INTERSE:CTION (OF A,- ANO Bo PL AN)

-

AXIS OF LIGHT SOURCE
F i g . 9:
C-planes w i t h r i g i d c o u p l i n g t o t h e l i g h t s o u r c e

i5

CIE i 0 8 7
4.4

e

9006145 0003043 969 M

CONICAL SURFACE5 ( F i g . 1 0 )

For some goniophotometers it is c o n v e n i e n t t o m a s u r e t h e luminous i n t e n s t y d i s t r i b u t i o n curves a t c o n s t a n t p o l a r a n g l e s and t o d e s c r i b e t h e r e s u l t s as c u r v e s on c o n i c a l s u r f a c e s . The a x i s o f t h e cone c o r r e s p o n d s t o t h e l i n e o f i n t e r s e c t i o n o f t h e C-planes.

LIGHT SOURCE LUMINOUS INTENSITY DISTRIBUTION
-CI
J

/-

F i g . 10: Conical surfaces

4.5

SYMBOLS FOR PLANE ANGLES

The t i l t a n g l e s o f planes a r e d e s i g n a t e d by an i n d e x , The t i l t a n g l e s of the A- and ?-planes a r e taken from -180 o t h r o u g h O o t o 180 O , t h o s e o f t h e C-planes f r o m O o t o 360 o ( s e m i p l a n e s ) . The opening a n g l e o f t h e c o n i c a l surfaces is m?aSiJred r e l a t i v e to t h e l i n e o f i n t e r s e c t i o n o f t h e C-planes. The f o l l o w i n g symbols a r e iised ( f o r a n g l e symbols see F i g s . 6-10):

-

t h e a n g l e s i n t h e A-plane have t h e symbol a and a r a measured from t h e line p e r p e n d i c u l a r t o t h e l i n e of i n t e r s e c t i o n of t h e A- p l a n e s
t h e a n g l e s i n t h e B-planes

have t h e symbol ? and are measured from the line p e r p e n d i c u l a r t a t h e line of i n t e r s e c t i o n o f t h e B-planes

The

t h e a n g l e s i n t h e C-plane have t h e symbol y and a r e measured from t h e line o f i n t e r s e c t i o n o f t h e C-planes i n t h e downward d i r e c t i o n t h e a n g l e s on t h e c o n i c a l s u r f a c e s have t h e symbol C and a r e measured f r o m t h e Co-plane.

t i l t a n g l e s o f t h e p l a n e s a r e added as i n d i c e s t o t h e r e l e v a n t p l a n e s .
Ib

~

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CIE 70 87

7 0 0 6 3 4 5 0003044 B T 5

4.6

RELATIONSHIPS

A c e r t a i n d i r e c t i o n i n e a c h system o f p l a n e s is c h a r a c t e r i z e d by t d o angles:

-

an a n g l e i n one p l a n e or c o n i c a l s u r f a c e and a n g l e f o r t h e t i l t o f t h e p l a n e o r c o n i c a l s u r f a c e .

T a b l e 1 shows t h e a n g l e symbols commonly u s e d i n t h e v a r i o u s systems o f planes.

TABLE 1
Angle symbols System a A-p 1 n e s B-planes
C -p 1 n e s a

Angle i n t h e plane
a
?
Y

T i l t angle o f plane
A

B
C

Conical surfaces

C

Y

The c o n v e r s i o n e q u a t i o n s l i s t e d i n T a b l e 2 h o l d f o r t h e a n g l e s i n T a b l e 1.

TABLE 2
C o n v e r s i o n e q u a t i o n s f o r systems o f p l a n e s Direction

1

T i l t a n g l e of p l a n e ]

I

Angle i n t h e p l a n e

sin ?
cos y

= sin A
= cos A
B

A,a

C,Y A,a

t a n A = tan ?/cos B t a n C = s i n B/tg 3 t a n A = c o s C.tg Y

sin a Is i n c o s Y = COS sin a = s i n s i n i3 = c o s

B
C C

. cos a . cos a . cos ? . B . sin Y . sin y
COS

17

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9006345 0003045 733
[2,4,18]

5 GONIOPHOTOMETER WITH FACILITY FOR TURNING THE LIGHT %URCE .
5.1

PRINCIPLE

I n t h e s e goniophotorneters t h e l i g h t source is t u r n e d around a v e r t i c a l a s well a s a h o r i z o n t a l a x i s . T h e photometer head is f i x e d , Accurate results f o r t h e luminous i n t e n s i t y d i s t r i b u t i o n w i t h t h i s t y p e o f goniophotometer were o n l y o b t a i n e d f o r l i g h t s o u r c e s i n which t h e luminous i n t e n s i t y d i s t r i b u t i o n is independent o f o r i e n t a t i o n and t e m p e r a t u r e .
Note 1 :

For measurements o f t h e luminous i n t e n s i t y d i s t r i b u t i o n o f f l u o r e s c e n t l a m p s and l u m i n a i r e s w i t h f l u o r e s c e n t lamps t h i s t y p e o f goniophotometer c a n be used p r o v i d e d t h a t f o r p o s i t i o n s o f t h e l i g h t s o u r c e d i f f e r i n g froin t h e normal b u r n i n g p o s i t i o n t.he luminous i n t e n s i t y i n each d i r e c t i o n is h e l d c o n s t a n t by means o f an a u x i l i a r y d e t e c t o r or t h a t t h e ap2 r o p r i a t e c o r r e c t i o n f a c t o r s are a p p l i e d ( s e e s e c t i o n 5 . 4 ) .
Yote 2: The o p t i c a l d i s t a n c e between l i g h t s o u r c e and photometer head c a n be inc r e a s e d by t h e u s e o f a d e f l e c t i o n mirror mounted at t h e f a r wall o f t h e S e l e c t i v e r e f l e c t i o n and p o l a r i z a t i o n by t h e m i r r o r measuring room, m u s t be t a k e n i n t o account.

5.2
.

APPLICATION

Goniophotometers with a f a c i l i t y for t u r n i n g t h e l i g h t s o u r c e s h o u l d o n l y be used t o measure i n c a n d e s c e n t lamps arid f l u o r e s c e n t lamps o r lumin a i r e s f i t t e d w i t h t h e s e lamps. These goniophotometers a r e t h e m s advanot t a g e o u s t y p e r e g a r d i n g c o n s t r u c t i o n and p r i c e . They a r e u s u a l l y used f o r t h e d e t e r m i n a t i o n of t h e luminous i n t e n s i t y a c c o r d i n g t o t h e p h o t o m e t r i c The use of an a u x i l i a r y d e t e c t o r ( s e c t i o n 5.4) is u s u a l l y d i s t a n c e law. required 5.3
CONSTRUCTION

PRINCIPLES

There are t h r e e t y p e s o f g o n i o p h o t o m e t e r s with f a c i l i t i e s f o r t u r n i n g t h e l i g h t source:
Type

1

Fixed h o r i z o n t a l axis and a moveable a x i s p e r p e n d i c u l a r t o t h e f i x e d h o r i z o n t a l a x i s ( F i g . i l ) [ i 9 ] . Measurements are made i n t h e A- or B-planes, when the l i g h t s o u r c e is t u r n e d around t h e h o r i z o n t a l axis and t h e second a x i s is i n a f i x e d p o s i t i o n . 18

~~

~~~

~

CIE 7 0 ? 7 111 9006345 O003046 678 111

F i g . 11: Goniophotometer with f a c i l i t y f o r t u r n i n g t h e l i g h t source, t y p e
1.

Type 2

F i x e d v e r t i c a l a x i s , moveable h o r i z o n t a l a x i s ( F i g . 1 2 ) . ments are made i n the A- o r B-planes.

Meacure-

.-o PHOTOMETER

\

F i g . 12: Goniophotometer w i t h f a c i l i t y f o r t u r n i n g t h e l i g h t s o u r c e , t y p e 2.

5.4

A U X I L I A R Y DETECTORS

[2,3]

L i g h t sources f o r which t h e ( a b s o l u t e ) luminous i n t e n s i t y d i s t r i b u t i o n changes with a change i n b u r n i n g p o s i t i o n b u t n o t t h e r e l a t i v e luminous i n t e n s i t y d i s t r i b u t i o n (e.g., f l u o r e s c e n t lamps or l u m i n a i r e s w i t h f l u o r e s c e n t l a m p s ) can be measured w i t h a goniophotometer i n which t h e l i g h t s o u r c e is t u r n e d i f t h e measurements a r e c o r r e c t e d by means of an a u x i l i a r y d e t e c t o r . For p r e c i s i o n measurements t h i s method i s n o t recommended. 4n i l l u m i n a n c e meter w i t h a s e p a r a t e photometer head can be u s e d as r e f e r e n c e d e t e c t o r . The a u x i l i a r y d e t e c t o r must be f i x e d t o t h e l i g h t s o u r c e , s o t h a t it f o l l o w s its movements. I t s h o u l d p r e f e r a b l y be i l i u -

19

~

C I E 70 87
?yDe 3 :

9006345 O003047 504
MeasureType 3 is

F i x e d v e r t i c a l axis, m c v e a b l e h o r i z a r i t a l a x i s >:Fig. 13,,

:nentc a r e made in t h e C-planes sr c o n i c a l surFaces. e q u i v a l r n t Is0 t y p e 2 if t h e l i g h t s o u r c e is t d r n e d by ?U d e g r e e s .
A

ba

1

PHOTOMETER HEAD

-=O

Fig.

13: Goniophotometer w i t h f a c i l i t y f o r t u r n i n g t h e l i g h t s o u r c e , t y p e
3.

ininated by a l l parts of t h e e m i t t i n g area and s h o u l d n o t mask t h e i l l u m i n a t i o n by t h e l i g h t s o u r c e on t h e photometer head used f o r measuring t h e l u minous i n t e n s i t y . The o n l y s t r i n g e n t r e q u i r e m e n t s on t h e auxiliary d e t e c t o r a r e f o r small faThe r e s t o f the p a r a m e t e r s c h a r a c t e r i z i n g the t i g u e and d r i f t parameters. p r o p e r t i e s of i l l u m i n a n c e meters a r e o f l e s s importance.

For t h e measurement of t h e luminous i n t e n s i t y d i s t r i b u t i o n one has t o obt a i n t h e r e a d i n g on t h e a u x i l i a r y d e t e c t o r i n t h e norinal b u r n i n g p o s i t i o n of t h e l i g h t s o u r c e . On t u r n i n g t h e l i g h t s o u r c e around a h o r i z o n t a l a x i s t h e r e a d i n g on t h e a u x i l i a r y d e t e c t o r can be m a i n t a i n e d a t a c o n s t a n t level v i a a corresponding adjustment of t h e supply voltage.
A second p o s s i b i l i t y c o n s i s t s i n keeping t h e supply voltage of t h e l i g h t s o u r c e c o n s t a n t and c o r r e c t i n g t h e measured luminous i n t e n s i t y i n each d i r e c t i o n by means o f a c o r r e c t i o n f a c t o r .

T
K

I,,,,

Luminous i n t e n s i t y of l i g h t source Correction factor i4easured ( i n a c c u r a t e ) l u m i n o u s i n t e n s i t y

The c o r r e c t i o n F a c t o r K f o l l o w s f r o m t h e measured r e a d i n g s on t h e a u x i l i a r y d e t e c t o r as

20

Eo
Eo

Reading on t h e a u x i l i a r y d e t e c t o r f o r t h e l i g h t s o u r c e i n t h e p r e s c r i b e d burning p o s i t i o n ( a f t e r burn-in) Reading on t h e a u x i l i a r y d e t e c t o r f o r t h e l i g h t source i n t h e p o s i t i o n c h a r a c t e r i z e d by t h e a n g l e 8 .

6 GONIOPHOTOMETER WITH MOVING PHOTOMETER HEAD [ 2,4,18] . 6.1

PRINCIPLE

I n these g o n i o p h o t o m e t e r s t h e l i g h t s o u r c e is t u r n e d around a v e r t i c a l a x i s and t h e photometer nead moves around t h e l i g h t s o u r c e i n a v e r t i c a l plane I n s t e a d of a moving photometer head one c a n a l s o use a number o f f i x e d phot o m e t e r heads t h a t are p o s i t i o n e d i n a v e r t i c a l p l a n e , c o r r e s p o n d i n g t o the movement o f a photometer head. The p o s s i b i l i t y a l s o e x i s t s t o r e p l a c e t h e p r o c e s s o f t u r n i n g t h e lamp by a n arrangement o f photometer heads i n a number o f v e r t i c a l p l a n e s . Note: The u s e o f f i x e d photometer heads i n one o r more v e r t i c a l p l a n e s req u i r e s a number o f photometer h e a d s c o r r e s p o n d i n g t o t h e d e s i r e d a n g u l a r s t e p s . A l l photometer h e a d s have t o be c a l i b r a t e d s e p a r a t e l y , which is i n p r a c t i c e q u i t e a d i s a d v a n t a g e . I n t u r n i t is p o s s i b l e t o u s e a simp l e r mechanical c o n s t r u c t i o n and t h e measuring time is s i g n i f i c a n t l y reduced. 6.2 APPLICATION

S i n c e t h e l i g h t s o u r c e i s t u r n e d o n l y about t h e v e r t i c a l a x i s i n these photometers and can t h e r e f o r e be measured i n i t s normal b u r n i n g , p o s i t i o n it is p o s s i b l e t o measure a l l k i n d s o f lamps and l u m i n a i r e s c o n t a i n i n g t h e m . The p r e r e q u i s i t e f o r a n a c c u r a t e measurement is a s u f f i c i e n t l y l a r g e d i s t a n c e between t h e l i g h t s o u r c e and t h e photorneter head; t h i s distance depends o f c o u r s e on t h e photometer head used. I f a photometer head f o r i l l u m i n a n c e measurements is u s e d i t is g e n e r a l l y n e c e s s a r y t o use a room o f r e l a t i v e l y g r e a t d e p t h and h e i g h t .
6.3

CONSTRUCTION PRINCIPLES

For goniophotometers w i t h a moving photorneter head t h e r e a r e b a s i c a l l y three types

21

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CIE 70 87
Tjpe 1:

9006345 0003049 387 I

The l i g h t s o u r c e is t t r r n e d at the p o i n t of i n t e r s e c t i o n o f t h e h o r i z o n t a l and v e r t i c a l axes around a v e r t i c a l a x i s . The p h o t a meter head 1s t u r n e d around a h o r i z o n t a l a x i s (Fig" 14). 4fternat i v e l y t h e photometer head can be moved on a c i r c l e i n t h e v e r t i c a l p l a n e a r o u n d t h e l i g h t s o u r c e w i t h o u t any mechanical coupling with the l i g h t s o u r c e ( F i g . 7 5 ) .

6..
PHOTOMETER HEAD
i
Fig. 14: Goniophotometer w i t h moving photometer head, t y p e 1.

The photo-

meter head is t u r n e d around a h o r i z o n t a l a x i s .

LIGHT SOURCE .-.-.-.-.-.--

PHOTOME; ER HEAD

c

I l

/A
The photo-

/

T i o . 15

Goniophotometer w i t h moving photometer h e a d , t y p e 1. d i r e c t mechanical c o u p l i n g .

meter head moves on a c i r c l e around t h e measuring o b j e c t w i t h o u t

22

CIE 7 0 87

e

?OObL45 0003050 O T 7

Type 2 :

L i g h t source and photometer head a r e at t h e o p p o s i t e ends o f a beam, which is t u r n e d around a h o r i z o n t a l a x i s through t h e centre o f t h e beam f’201. The photometer head is r i g i d l y f i x e d t o t h e beam, w h i l e t h e h o r i z o n t a l s p i n d l e s u p p o r t i n g t h e l u m i n a i r e e n s u r e s t h a t t h e l u m i n a i r e hangs down l i k e a plumb bob a s t h e beam r o t a t e s . T h e l i g h t s o u r c e is t u r n e d i n t h e pres c r i b e d b u r n i n g p o s i t i o n around a v e r t i c a l a x i s and t h e photometric c e n t r e of t h e l i g h t s o u r c e is t u r n e d around a h o r i z o n t a l a x i s i n a C-plane ( F i g . 1 6 ) . I t must be mentioned t h a t many t y p e s of lamps have a temperature-dependent l i g h t output. T h e r e f o r e a i r v e l o c i t y because of lamp movement must be k e p t low. R o t a t i n g t h e lamps c a n a l s o g i v e r i s e t o changes because of c e n t r i f u g a l movement o f , f o r instance, l i q u i d metal. The r e q u i r e d room d e p t h i s only h a l f t h a t of t y p e 1. The use o f t h i s t y p e is o n l y meaningful i n c o n j u n c t i o n w i t h a photometer head f o r il1uminance.measurements.

F i g . 16: Goniophotometer w i t h moving photometer head, t y p e 2. Movement o f photometer head a n d l i g h t s o u r c e on a c i r c l e i n a v e r t i c a l p l a n e . Type 3 :
T h e l i g h t s o u r c e is t u r n e d around a v e r t i c a l a x i s i n a f i x e d p o s i tion. The p h o t o m e t e r head is moved along s t r a i g h t l i n e s i n Cp l a n e s ( h o r i z o n t a l l y and v e r t i c a l l y ) w i t h o u t mechanical c o u p l i n g t o t h e l i g h t source ( F i g . 1 7 ) . The moving p h o t o m e t e r head c a n be a l i g n e d w i t h its o p t i c a l a x i s on t h e p h o t o m e t r i c c e n t r e of t h e l i g h t source. If t h e r e s p o n s i v i t y of the photometer head a s a f u n c t i o n o f t h e a n g l e o f i n c i d e n c e i s t a k e n i n t o a c c o u n t numeric a l l y i t c a n a l s o s t a y i n a f i x e d s p a t i a l o r i e n t a t i o n ( o p t i c a l axi s o f photometer head v e r t i c a l or h o r i z o n t a l ) . The i n f l u e n c e o f t h e change i n d i s t a n c e between l i g h t s o u r c e and photometer head must be t a k e n i n t o a c c o u n t n u m e r i c a l l y .

23

.~

CIE i 0 8 7

9006L45 0003051 T35 H

Y
I

@ LIGHT SOURCE

I
I

DIRECTIONS OF MOTION

'ig.

17: Goniophotometer w i t h moving photometer head, t y p e 3 . photometer head on a h o r i z o n t a l oc v e r t i c a l l i n e .

Movement o f

For goniophotometers of t y p e s 1 and 3 i t is p o s s i b l e t o use a number o f f i x e d photometer heads - e a c h c a l i b r a t e d separately - i n s t e a d o f t h e moving
one.

Their number depenas on t h e r e q u i r e d a n g u l a r r e s o l u t ion and t h u s s i g n i f i cantly on t h e k i n d o f l i g h t s o u r c e . The measuring time o f such a goniophotometer can b e v e r y s h o r t . C a l i b r a t i o n and a g e i n g problems may be cons i d e r a b l e w i t h t h e s e multi-photometer head systems. Goniophotometers of t h e f i r s t t y p e can be f i t t e d w i t h e i t h e r a photometer head f o r t h e measurement o f i l l u m i n a n c e or w i t h a photometer head f o r t h e measurement o f luminance. Goniophotometers of t h e second and t h i r d t y p e are used e x c l u s i v e l y w i t h photometer heads f o r t h e measurement o f i l l u m i n a n c e .

For goniophotometers with moving photometer head measurements a r e made i n C-planes or on c o n i c a l s u r f a c e s .

7. GONIOPHOTOMETERS WITH ROTATING MIRROR
7.1
PRINCIPLE

I n t h e s e g o n i o p h o t o m e t e r s t h e l i g h t s o u r c e is t u r n e d around a v e r t i c a l a x i s and a m i r r o r arrangement around a h o r i z o n t a l a x i s . The p o s i t i o n of t h e photometer head i s f i x e d .
24

CIE 70 8 7 I9006345 0003052 9 7 3 I

No te :

The o p t c a l d i s t a n c e between l i g h t s o u r c e and photometer head can b e i n c r e a s e d by t h e cise of a d e f l e c t i n g m i r r o r t h a t i s p o s i t i o n e d a t t h e f a r

end o f .he measuring room. S e l e c t i v e r e f l e c t i o n and p o l a r i z a t i o n t o the mirror m u s t be taken i n t o account.
7.2

due

APPLICATION

S i n c e t h e l i g h t s o u r c e is t u r n e d only around a v e r t i c a l a x i s i n these goniophotometers and can t h e r e f o r e be measured i n t h e p r e s c r i b e d b u r n i n g p o s i t i o n , a l l k i n d s o f lamps and l u m i n a i r e s c o n t a i n i n g t h e m can be measured.
T h e p r e r e q u i s i t e f o r an a c c u r a t e measurement i s a s u f f i c i e n t l y l a r g e d i s t a n c e between l i g h t s o u r c e and photometer head, which depends on t h e k i n d o f photometer head used.

7.3

CONSTRUCTION

PRINCIPLES

Goniophotometers w i t h r o t a t i n g m i r r o r are today u s u a l l y b u i l t with a s i n g l e m i r r o r f o r easier a l i g n m e n t . Goniophotometers w i t h s e v e r a l m i r r o r s are, however, a l s o known [ 211. F i g u r e s 18 and 19 show t h e c o n s t r u c t i o n p r i n c i p l e o f a goniophotometer w i t h r o t a t i n g m i r r o r . No d i r e c t l i g h t from t h e l i g h t s o u r c e must reach t h e p h o t o m e t r i c head. The mirror must be s u f f i c i e n t l y l a r g e s o as not t o cause v i g n e t t i n g i n t h e beam p a t h .

-HOLDER FOR LIGHT SOURCE

----e-

1

PHWOME:TER HEAD

f

l
BAFFLES
F i g . 18: Goniophotometer w i t h r o t a t i n g m i r r o r !mircor on o p t i c a l axis’:

25

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CIE 70 8 7

7006145 0003053 A08 I

B a f f l e s must be p l a c e d between mirror and photometer h e a d s o t h a t no d i r e c t light from t h e light s o u r c e and, p r e f e r a b l y , a l s o RO light r e f l e c t e d f r o m

the f l o o r , t h e c e i l i n g o r t h e w a l l s can r e a c h t h e photometer Measurements are made i n C-planes or on c o n i c a l s u r f a c e s .

head.

n

/

OPTICAL A X I S

--MIRROR
F i g 19:

PHOTOMETER HEAD

Goniophotorneter w i t h r o t a t i n g m i r r o r (lamp on o p t i c a l a x i s ) .

The measurement o f t h e error caused by t h e t u r n i n g mirror s h o u l d be p e r formed a c c o r d i n g t o s e c t i o n 3 . 2 . 2 .

8. ANGLE MEASUREMENT 8.1

POSSI6ILITIES

For the measurement o f luminous i n t e n s i t y i n a d e f i n e d d i r e c t i o n two a n g l e s must be d e t e r m i n e d a c c o r d i n g t o t h e p a r t i c u l a r system o f p l a n e s used. The p o s i t i o n i n g o f t h e l i g h t s o u r c e i n t h e goniophotometer w i l l u s u a l l y b e done by hand o r by motor. If by motor, i t c a n be c o n t r o l l e d by hand o r automatically. I n t h e l a t t e r c a s e an e l e c t r i c r o t a t i o n measuring I n a l l cases an a n g l e measuring d e v i c e can be used. d e v i c e is r e q u i r e d . P o s s i b l e methods are:
a d j u s t m e n t o f t h e goniophotometer by hand, r e a d i n g O F t h e a n g l e s from a n g l e scales adjustment o f t h e goniophotorneter by hand or by motor, a n g l e encoding by means o f a p o t e n t i o m e t e r , i n which t h e v o l t a g e produced is a measure o f t h e a n g u l a r posit i o n use o f s t e p p i n g motors f o r \orhich t h e number o f p u l s e s is a measure of t h e a n g u l a r position

-

-

26

~~~

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CIE 70 87

9006145 0003054 744 0

u s e o f a n g l e encoders ( p u l s e g e n e r a t o r s ) i n which t h e number o f p u l s e s is c o u n t e d . An a d d i t i o n a l d e t e r m i n a t i o n of tlie z e r o p o s i t i o n hac t o br: p e r f ormeú

use of a b s o l u t e a n g l e e n c o d e r s , which do n o t r e q u i r e a z e r a a d j u s t n e n t , A p a r t i c u l a r p o s i t i o n r e m a i n s encoded e v e n i f t h e power s u p p l y i s s w i t c h e d o f f . Any p a r t i c u l a r reference a n g l e can be d e f i n e d E S t h e zero p o s i t i o n f o r s p e c i f i c measurements, w i t h no l o s s o f t h e a b s o l u t e z e r o p o s i t i o n , which is c o n t i n u a l l y a c c e s s i b l e .
The c u r r e n t p o s i t i o n u s u a l l y i s i n d i c a t e d d i g i t a l l y . 8.2
REQUIREMENTS

A s u f f i c i e n t l y a c c u r a t e p o s i t i o n i n g o f t h e l i g h t s o u r c e m u s t be poss i b l e . F o r measuring a r r a n g e m e n t s w i t h v a r i a b l e a n g u l a r s t e p s it is recommended t o choose an a n g u l a r r e s o l u t i o n of 0 , l O . A r e s o l u t i o n o f 0,Ol o is possible.

t4easures s h o u l d be t a k e n t o e n s u r e t h a t t h e i n d i c a t e d p o s i t i o n is i d e n t i c a l t o t h e actual p o s i t i o n of t h e l i g h t source and is n o t r e n d e r e d i n a c c u r a t e by t h e mechanical i n s t a b i l i t y o f t h e goniophotometer. T h i s means t h a t a heavy c o n s t r u c t i o n o f t h e m e c h a n i c a l parts o f t h e goniophotometer is necess a r y , which can i n f l u e n c e t h e p r i c e of t h i s equipment i n an i m p o r t a n t manner.

9. PHOTOELECTRONICS AND DATA PROCESSING
With t h e p h o t o e l e c t r o n i c s one i n c l u d e s t h e e l e c t r o n i c s f o r t h e a c q u i s i t i o n and processing o f t h e s i g n a l from t h e photometer head (ctsually an o p e r a t i o n a l a m p l i f i e r with f e e d b a c k ) w i t h a d d i t i o n a l c i r c u i t s f o r t h e d i g i t a l o r a n a l o g d i s p l a y of t h e luminous i n t e n s i t y as well a s s u i t a b l e f o r c o n n e c t i o n t o a computer o r XY-recorder. Where outputs, e.g., a p p l i c a b l e , t h e power s u p p l y f o r a t h e r m o s t a t t e d photometer head is a l s o part o f t h e photoelectronics. C i r c u i t s f o r a u t o - r a n g i n g are a l s o a u s e f u l f e a tU r e .
AC

o p e r a t e d lamps, e s p e c i a l l y d i s c h a r g e l a m p s , will have a certainrnodulation o f t h e l i g h t o u t p u t a t a f r e q u e n c y of 2 times t h e suppl:-( f r e q u e n c y . T h e measuring r e s u l t s s h o u l d be u n a f f e c t e d by t h i s modulation, by means o f a s u f f i c i e n t l y l o n g time c o n s t a n t i n t h e e l e c t r o n i c s or by tirrie i n t e g r a t i o n . However, t h i s s h o u l d nut i n f l u e n c e t h e measuring r e s u l t s as & f u n c t i o n of t h e goniophotorneter s p e e d by measuring "on t h e f l y . "

F o r OC powered lamps t h e t o t a l measuring time c a n t h e r e f o r e a s ~ a l l y Li.: s h o r t e r than f o r AC powered ones.

27

~~

~

~

CIE 7 0 87

700bL45 0003055 680

=

The p r o p e r t i e s o f t h e photometer head i n c o n j u n c t i o n w i t h t h e p h o t o e l e c t r o -

: l i e s h a v e t o conform t o t h e same s p e c i f i c a t i o n s a s r e q u i r e d f o r i l l u m i n a n c e qr I m i n a n c e meters 161.
T h e a c q u i s i t i o n of the measured v a l u e s (sets of one luminous i n t e n s i t y r e a -

jiq3, two a n g u l a r p o s i t i o n s and, where a p p l i c a b l e , a r e a d i n g from an auxi !iary d e t e c t o r ) c a n be performed:

.-

khrough manual r e g i s t r a t i o n
a n a l o g or d i g i t a l f o r m

of

t h e d e s i r e d q u a n t i t i e s d i s p l a y e d i n an

by p r i n t i n g t h e s e t of measured values on a s u i t a b l e p r i n t e r

by d i r e c t p l o t t i n g of t h e luminous i n t e n s i t y d i s t r i b u t i o n on an XY-re-

c o r d e r i n p o l a r or c a r t e s i a n c o o r d i n a t e s

-

by s t o r a g e i n t h e memory o f a s u i t a b l e computer.

I f a completely a u t o m a t i c measurement and a c q u i s i t i o n o f t h e luminous i n t e n s i t y d i s t r i b u t i o n i s r e q u i r e d , t h e computer t o be u s e d f o r t h e n e c e s s a r y c a l c u l a t i o n s and t h e p r i n t i n g o f t h e measured v a l u e s s h o u l d be chosen on t h e b a s i s of t h e i n f o r m a t i o n r e q u i r e d f o r t h e l i g h t source. T h i s i n c l u d e s g r i n t i n g of t h e luminous i n t e n s i t y d i s t r i b u t i o n i n t h e form o f t a b l e s and g r a p h s r-51. I n a d d i t i o n : f o r lamps, t h e p r i n t i n g o f t h e luminous f l u x velue and of t h e luminous e f f i c a c y ; f o r l u m i n a i r e s , the t o t a l luminous clux of t h e luminaire, t h e l i g h t o u t p u t r a t i o of t h e l i m i n a i r e , d i s t r i b u t i o n of t h e mean luminance ( F o r t h e e v a l u a t i o n o f t h e g l a r e l i m i t a t i o n ) ; f o r f l o o d l i g h t s , t h e h o r i z o n t a l and vertical one-tenth-peak divergence ( s p r e a d ) o f t h e u t i l i z e d f l u x , t h e u t i l i z a t i o n f a c t o r , etc.

10.

GENERAL MEASURING CONDITIONS

lQ.1 OPERATING CONDITIONS 4 1 1 lamps s h o u l d be o p e r a t e d and measured, u n l e s s o t h e r w i s e a g r e e d , i c c o r d i n g t o t h e c o n d i t i o n s s p e c i f i e d i n t h e a p p l i c a b l e I E C recommendations and n a t i o n a l s t a n d a r d s . I t is essential t o s t a t e whether t h e measurements a r e made a t nominal v o l t a g e , c u r r e n t o r power. This ensures t h a t the r e s u l t s can be compared w i t h v a l u e s measured a t o t h e r l a b o r a t o r i e s w i t h i n t h e u n a v o i d a b l e measuring u n c e r t a i n t y .
T h e v a l u e s o f t h e q u a n t i t i e s t o be f i x e d s h o u l d be i n f l u e n c e d as l i t t l e a s p o s s i b l e by t h e measuring and o p e r a t i n g f a c i l i t i e s . Unavoidable i n f l u e n c e s s h o u l d Se taken i n t o a c c o u n t i n t h e e v a l u a t i o n of t h e measurements.

28

C a l i b r a t i o n should be performed w i t h means calibrated directly w recognized standards. indirectly
i n

(lamps, measuring equipment)
with internationally

comparison

10.2 A G E I N G
The o p e r a t i n g parameters o f lamps change o v e r t h e i r l i f e t i m e t o varyi n g degrees. Changes a r e e s p e c i a l l y pronounced over the f i r s t p a r t o f their lifetime. I n o r d e r t o achieve a s u f f i c i e n t degree o f r e p e a t a b i l i t y

o f measurements i t i s t h e r e f o r e necessary t o age t h e lamps.
The d u r a t i o n o f ageing i s s p e c i f i e d For t h e d i f f e r e n t types o f lamps i n t h e a p p l i c a b l e I E C recommendations and n a t i o n a l standards.

10.3

BURNING P O S I T I O N

The o p e r a t i n g p o s i t i o n o f l i g h t sources must comply w i t h the a p p l i c able IEC recommendations and n a t i o n a l standards o r w i t h t h e s p e c i f i c a t i o n s o f t h e manufacturer and t h e a p p l i c a t i o n . The b u r n i n g p o s i t i o n must be s t a t e d i n the measuring r e p o r t .

10.4 AMBIENT TEMPERATURE
The l i g h t sources s h o u l d be operated d u r i n g the measurement i n a d r a u g h t - f r e e room i n such a way t h a t t h e convection f l o w o f t h e s u r r o u n d i n g a i r i s n o t impaired. Photometric measurements a r e u s u a l l y performed a t an ambient temperature o f 25 O C . F o r l i g h t s o u r c e s w i t h a s t r o n g l y temperat u r e dependent luminous f l u x t h e temperature t o l e r a n c e s h o u l d b e f 1 O C ,

I f measurements a r e made a t a f o r o t h e r l i g h t sources i t s h o u l d be f 3 O C . d i f f e r e n t ambient temperature t h i s temperature has t o be s t a t e d .
The luminous f l u x o f some s p e c i a l lamps i s measured a c c o r d i n g t o t h e s p e c i f i c a t i o n s o f t h e manufacturer i f t h e lamp i s operated w i t h i n a d e f i n e d and prescribed substitute luminaire. The temperature should be measured w i t h a thermometer w i t h a r e s o l u t i o n o f a t least 0,I ' C . The temperature measurements s h o u l d be done a t a repres e n t a t i v e spot and a t about t h e same h e i g h t as t h e l i g h t source. The d i s t a n c e between t h e temperature sensor and the p h o t o m e t r i c c e n t r e o f t h e l i g h t source t o be measured s h o u l d exceed h a l f t h e l a r g e s t h o r i z o n t a l e x t e n t o f t h e l i g h t soiirce by C;,5 in i n t h e case O F a goniophotorneter. The temperature sensor m i s t b e s h i e l d e d f r o m d i r e c t i r r a d i a t i o n by t h e l i g h t

s o u r c e t o be measured.
29

10.5 VIBRATION A N D CHOCK

When s w i t c h e d on, most lamps s h o u l d n o t be s u b j e c t e d t o a c c e l e r a t i o n s exceeding 10 m/s2 (4-3000 Hz) o r p o s i t i o n a l c h a n g e s exceeding 30 mm (up t o 4 k ) . However, i t i s n o t p o s s i b l e t o g i v e a s i n g l e s e t o f l i m i t i n g v a l u e s f a r a l l t y p e s of lamps a n d l u m i n a i r e s .

10.6 C T A B I L I Z A T I O N PERIOD
t h e s t a b i l i z a t i o n p e r i o d t o achieve a s t a b l e s t a t e of a l l p a r a m e t e r s i m p o r t a n t For t h e measurement. During t h e s t a b i l i z a t i o n t h e same o p e r a t i n g c o n d i t i o n s s h o u l d apply a s d u r i n g t h e f o l l o w i n g measurement. Special a t t e n t i o n s h o u l d be p a i d t o avoid changes i n t h e b u r n i n g p o s i t i o n and t h e s p e c i f i e d o p e r a t i n g p a r a m e t e r s ( e . g . , nominal v o l t a g e , power and c u r r e n t ) . The r e q u i r e d s t a b i l i z a t i o n p e r i o d It depends on t h e type OF l i g h t s o u r c e and t h e o p e r a t i n g c o n d i t i o n s . s h o u l d be checked by c o n t i n u o u s m o n i t o r i n g o f the r e a d i n g s . A l i g h t s o u r c e c a n be c o n s i d e r e d a s s t a b i l i z e d i f the c o r r e s p o n d i n g r e a d i n g s no longer show a t r e n d i n one d i r e c t i o n .
of

I t is t h e purpose

Note:

Some

l i g h t s o u r c e s remain s t a b l e f o r some time and then c h a n g i n g a g a i n u n t i l a new s t a b l e s i t u a t i o n is reached.

start

10.7 ELECTRICAL MEASUREMENTS

10.7.1 MEASIJREMENT UNCERTAINTY
D i f f e r i n g r e s u l t s of p h o t o m e t r i c measurements a r e o f t e n caused by errors i n t h e measurement or t h e a d j u s t m e n t o f e l e c t r i c a l p a r a m e t e r s . For current and v o l t a g e (DC a n d A C ) t h e u n c e r t a i n t y f o r i n c a n d e s c e n t lamp measurements s h o u l d n o t exceed 0,l oh, w h i l e t h e c o r r e s p o n d i n g f i g u r e f o r AC current and v o l t a g e i n t h e c a s e of d i s c h a r g e lamps is 0,2 %. hlote:
For i n c a n d e s c e n t lamps an e r r o r i n t h e v o l t a g e of 1 % c a u s e s a d e v i a t i o n i n t h e luminous f l u x of about 4 /A. T h e same e r r o r i n c u r r e n t c a u s e s a n 8 % e r r o r i n luminous f l u x .

There s h o u l d be agreement a s t o which o f t h e p a r a m e t e r s t o be measured ( v o l t a g e , current, power) s h o u l d b e k e p t c o n s t a n t and what o t h e r c o n d i t i o n s one s h o u l d p o s s i b l y meet.
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9006345 0003058 39T I

10.7.2

POWER TYPE AND OPERATING MODE

With DC one can u s u a l l y measure m o r e accurately than w i t h AC, s i n c e f o r AC the l i g h t source as well a s the e l e c t r i c a l measuring i n s t r u m e n t s a r e s u b j e c t t o a g r e a t e r number of i n f l u e n c i n g q u a n t i t i e s (e.g., frequency, wave form, phase l a g ) . Because o f t h e sometimes s t r o n g dependence o f t h e photometric q u a n t i t i e s on t h e e l e c t r i c a l ones one should use s u p p l i e s t h a t a r e as s t a b l e as p o s s i b l e .

10.7.3

WIRING

Wires, b a l l a s t s and e l e c t r i c a l measuring instruments should be p o s i t i o n e d and, i f necessary, screened i n such a way t h a t an i n f l u e n c e o f exI f i t i s r e q u i r e d f o r some photometric measuret e r n a l f i e l d s i s avoided. ments t o determine t h e lamp v o l t a g e or power, t h e use o f a measuring lamp h o l d e r i s recommended. Not e :

A measuring lamp h o l d e r has four c o n t a c t s , two for t h e c u r r e n t supply (IL) two separate ones f o r t h e measurement o f t h e lamp v o l t a g e and (UL) d i r e c t l y a t t h e lamp socket. A f o u r e l e c t r o d e lamp h o l d e r reduces t h e v o l t a g e measuring e r r o r t o zero, because no measurable c u r r e n t f l o w s through t h e measuring c o n t a c t s , when u s i n g a h i g h impedance d i g i t a l v o l t m e t e r .

10.7.4 EXECUTION O THE ELECTRICAL MEASUREMENTS F

[ 221

When measuring with c u r r e n t , v o l t o r power meters, t h e v o l t m e t e r or t h e v o l t a g e p a t h o f t h e power meter s h o u l d be connected between l i g h t The measuring c u r r e n t (power) source and c u r r e n t meter ( o r c u r r e n t p a t h ) . o f t h e i n s t r u m e n t s themselves must be t a k e n i n t o account (see a l s o i n s t r u c t i o n s i n t h e a p p l i c a b l e IEC recommendations). The c a p a c i t y o f t h e c i r c u i t may i n f l u e n c e t h e r e s u l t s , e s p e c i a l l y i f h i g h e r f r e q u e n c i e s occur as f o r i n s t a n c e i n low pressure sodium vapour lamps. Grounding e r r o r s can also s u b s t a n t i a l l y i n f l u e n c e t h e measuring r e s u l t s .
F o r accurate AC measurements on discharge lamps, i n s t r u m e n t s should t h e " t r u e rins" t y p e t o cope w i t h harmonics. When measuring h i g h

be o f frequency operated discharge r e q u i r e d [ 231

.

lamps s p e c i a l

methods

and

instruments

are

113.7.5

MEASURING CIRCUIT
I n t h e case o f discharge lamps I E C recommendations s p e c i f y t h e

cir-

c u i t s f o r t h e l i g h t sources t o be measured.

31

1O . 8 BALLASTS

Measurements on d i s c h a r g e lamps a r e u s u a l l y made w i t h r e f e r e n c e b a l lasts. I f o t h e r b a l l a s t s a r e used ( e . g . , f o r measurements on l u m i n a i r e s ) , t h e b a l l a s t used s h o u l d be n o t e d i n t h e measuring p r o t o c o l .
10.9 SUPPLY VOLTAGE

Measureinents on i n c a n d e s c e n t lamps s h o u l d p r e f e r a b l y b e performed w i t h a DC s u p p l y because o f t h e h i g h e r accuracy o f t h e e l e c t r i c a l measurements. Measurements on d i s c h a r g e lamps g e n e r a l l y have t o be performed w i t h an AC supply The s u p p l y v o l t a g e d u r i n g a g e i n g s h o u l d b e s t a b l e t o w i t h i n 0,5 %, u r i n g d t h e actual measurement t o w i t h i n 0 , l % and f o r c a l i b r a t i o n s with i n c a n d e s cent lamps as s t a n d a r d s t o w i t h i n 0,OZ X. The f r e q u e n c y s h o u l d d i f f e r at most by 0 , i 5ó from t h e o n e for which t h e b a l l a s t is d e s i g n e d . The t o t a l harmonic c o n t e n t o f t h e AC s u p p l y v o l t a g e s h o u l d n o t exceed 3 %. For t h e o p e r a t i o n of h i g h p r e s s u r e l a m p s w i t h a h i g h p r o p o r t i o n o f reactive power t h e power s u p p l y s h o u l d b e chosen i n s u c h a way t h a t t h e r e q u i r e d rea c t i v e power can be met. The t o t a l harmonic content is d e f i n e d as t h e root-mean-square (r.m.s.) summation of t h e i n d i v i d u a l harmonic components, u s i n g t h e fundamental as 100 ?i. Note: This implies t h a t t h e source o f supply should have a s u f f i c i e n t l y low impedance compared w i t h t h e b a l l a s t impedance and care s h o u l d b e t a k e n t h a t t h i s a p p l i e s under a l l c o n d i t i o n s o f measurement.
EXECUTION OF THE MEASUREMENTS

10.10

For t h e measurement t h e p h o t o m e t r i c c e n t r e o f t h e l i g h t s o u r c e s h o u l d be p o s i t i o n e d a t t h e p o i n t o f i n t e r s e c t i o n o f t h e a x e s o f r o t a t i o n .
The result o f t h e measurement s h o u l d not b e i n f l u e n c e d by t h e movement o f t h e l i g h t source. Note:
For measurements on f l u o r e s c e n t lamps t h e v e l o c i t y o f r o t a t i o n s h o u l d

not e x c e e d 3 r e v o l u t i o n s p e r m i n u t e , t o a v o i d i n f l u e n c i n g t h e r e s u l t t h r o u g h t h e d r a u g h t caused by t h e r o t a t i o n .
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CIE 70 87 U 9006345 0003060 T 4 8

S t r a y l i g h t on t h e photometer head s h o u l d be reduced by t h e u s e o f b a f f l e s , which s h o u l d not c a u s e v i g n e t t i n g i n t h e beam p a t h . B e f o r e s t a r t i n g t h e measurements t h e l i g h t s o u r c e s h o u l d b e burned i n l o n g enough t o a t t a i n t h e r m a l e q u i l i b r i u m . A l l e l e c t r i c a l and photometric i n s t r u m e n t s s h o u l d b e s w i t c h e d on l o n g enough b e f o r e t h e s t a r t o f t h e measurements f o r t h e i r warm-up p e r i o d t o be exceeded a t t h e s t a r t of t h e measurement [ 6 1 .

11. CORRECTION O HEASUREMENT RESULTS F

I f t h e l i g h t s o u r c e is o p e r a t e d d u r i n g t h e measurement w i t h a v o l t a g e d i f f e r i n g from t h e nominal v o l t a g e , i f t h e a m b i e n t t e m p e r a t u r e d i f f e r s from t h e s p e c i f i e d one, or i f t h e l i g h t s o u r c e is measured i n a p o s i t i o n d i f f e r i n g from t h e p r e s c r i b e d one, t h e r e s u l t s s h o u l d be c o r r e c t e d i f p o s s i b l e .
A c o r r e c t i o n of t h e r e s u l t s due t o a v o l t a g e d i f f e r i n g from t h e nominal o n e is p o s s i b l e i f t h e r e l a t i o n s h i p between t h e luminous f l u x o f t h e lamp a n d R e s u l t s o b t a i n e d w i t h a d i f f e r e n t ambient ternperat h e v o l t a g e is known. F o r lamps w i t h a t e m p e r a t u r e t u r e can be c o r r e c t e d t o a c e r t a i n e x t e n t . dependent luminous f l u x , r e s u l t s c a n be c o r r e c t e d For a d i f f e r e n t ambient t e m p e r a t u r e i f t h e r e l a t i o n s h i p between luminous f l u x and ambient temperature is known. I n t h e c a s e of l u m i n a i r e s t h e t e m p e r a t u r e d i f f e r e n t i a l between l u m i n a i r e and ambient must be known a s w e l l . A c o r r e c t i o n due t o a d i f f e r e n t b u r n i n g p o s i t i o n is p o s s i b l e f o r i n c a n d e s c e n t and f l u o r e s c e n t lamps by means of a d d i t i o n a l measurements w i t h an auxi l i a r y d e t e c t o r ( s e e s e c t i o n 5.4).

12. PRESENTATION O RESULTS F

The results s h o u l d be p r e s e n t e d i n a s u i t a b l y chosen system of p l a n e s I t is a l s o a d v i s e i n c a r t e s i a n o r p o l a r c o o r d i n a t e s a n d i n t a b u l a r form. a b l e t o c o n v e r t t h e r e s u l t s t o t h o s e f o r t h e nominal luminous f l u x ( i f The nominal luminous f l u x known) of t h e lamp used i n t h e measurement. s h o u l d be s t a t e d .
For measurements on l u m i n a i r e s which can be p r o v i d e d w i t h d i f f e r e n t l a n p s of t h e same geometry ( d i m e n s i o n s and p o s i t i o n o f t h e e m i t t i n g a r e a ) , i t is recommended t o r e f e r t h e l u m i n o u s i n t e n s i t y t o a luminous f l u x o f t h e l a q s t o be f i t t e d i n t h e l u m i n a i r e o f 1000 l m [ 2 , 3 , 4 1 .

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7006345 00030bL 784 I

1 3 . 1 GONIOPHOTOMETER N I T H F A C I L I T Y FOR TURNING THE LIGHT SOURCE
F o i g o n i o p h o t o m e t w s o f t h i s t y p e t h e axes o f r o t a t i o n must be perpen-

d i c u l a r and must have a p o i n t o f i n t e r s e c t i o n . I t must be e n s u r e d t h a t t h e h o r i z o n t a l and v e r t i c a l a x e s r e a l l y correspond t o t h e d i r e c t i o n s i n question. T h i s requirement s h o u l d b e checked w i t h a high p r e c i s i o n l e v e l w i t h an u n c e r t a i n t y o f n o t more t h a n 0,Ol O .

A t t h e p o i n t o f i n t e r s e c t i o n o f t h e a x e s a m i r r o r with a good o p t i c a l s u r f a c e F i n i s h and 5 rnm d i a m e t e r is put i n t h e p o s i t i o n o f t h e l i g h t s o u r c e i n t h e p l a n e t h r o u g h t h e l i g h t c e n t r e o f t h e l i g h t s o u r c e , which h a s a normal i n t h e d i r e c t i o n of t h e o p t i c a l a x i s o f t h e goniophotorneter ( l i n e between t h e p o i n t o f i n t e r s e c t i o n o f t h e a x e s and t h e centre o f t h e measuring area o f t h e photometer h e a d ) .
The p o i n t of i n t e r s e c t i o n o f t h e a x e s and t h e c e n t r e o f t h e measuring a r e a A stable a r e t h e n a d j u s t e d t o t h e same h e i g h t by means of a h o s e l e v e l . laser is p o s i t i o n e d i n such a way t h a t t h e c e n t r e o f its e m i t t i n g a r e a c o r responds t o t h e c e n t r e o f t h e a c c e p t a n c e area o f t h e (removed) photometer head. I t s beam is d i r e c t e d a t t h e c e n t r e o f t h e o p t i c a l m i r r o r on t h e turning device for t h e l i g h t source. The t u r n i n g d e v i c e f o r t h e l i g h t s o u r c e i s a d j u s t e d i n such a laser beam is r e f l e c t e d back e x a c t l y o n t o i t s e l f . T h i s c a n be a w h i t e , d i f f u s e l y r e f l e c t i n g a r e a around t h e l a s e r e m i t t i n g v i s i b l e p o s i t i o n on i t o f t h e r e f l e c t e d laser beam. Then t h e a s follows: way that t h e checked w i t h a r e a and t h e p r o c e d u r e is

-

Goniophotometer t y p e s 1 and 2
I f t h e m i r r o r is t u r n e d around t h e v e r t i c a l a x i s ( i t is now a l s o v e r t i c a l For t y p e 2 g o n i o p h o t o m e t e r s ) t h e r e f l e c t e d laser beam s h o u l d h i t t h e w a l l s o f t h e photometer room on a h o r i z o n t a l l i n e . If t h e beam h i t s t h e wall t o t h e s i d e o f t h e p o i n t of i n t e r s e c t i o n of t h e axes of t h e t u r n i n g d e v i c e f o r t h e l i g h t s o u r c e and a t t h e h e i g h t o f t h e c e n t r e of t h e emitt i n g a r e a o f t h e l a s e r ( t o b e checked with hose l e v e l ) when t h e v e r t i c a l a x i s is t u r n e d by about 45 o i n e i t h e r d i r e c t i o n , t h e v e r t i c a l a x i s i s set correctly.

When r o t a t i n g t h e d i r e c t i o n around on t h e f l o o r or through t h e point

device for t u r n i n g t h e l i g h t source by 45 o i n e i t h e r t h e h o r i z o n t a l axis t h e r e f l e c t e d l a s e r beam i n c i d e n t the c e i l i n g should coincide with t h e v e r t i c a l l i n e of i n t e r s e c t i o n o f t h e a x e s .

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Goniophotometer t y p e 3
For t h i s t y p e o f goniophotometer t h e o r i e n t a t i o n o f t h e v e r t i c a l a x i s is checked i n t h e same way as f o r t y p e s 1 and 2 . T h e p o s i t i o n o f t h e h o r i -

z o n t a l a x i s is checked by t u r n i n g t h e m i r r o r around t h e h o r i z o n t a l axis. I n t h a t case t h e p o s i t i o n of t h e r e f l e c t e d l a s e r beam i n t h e p l a n e o f t h e measuring area o f t h e photometer head s h o u l d n o t change.

13.2 GONIOPHOTOMETER WITH MOVING PHOTOMETER HEAD
I n o r d e r t o check t h e o r i e n t a t i o n of t h e v e r t i c a l axis o f t h e t u r n i n g d e v i c e for t h e l i g h t s o u r c e , t h e p h o t o m e t e r head i s moved t o t h e l o w e s t A l a s e r is mounted i n p l a c e o f t h e l i g h t s o u r c e , w i t h p o s i t i o n (y = O ) . i t s beam d i r e c t e d a t t h e c e n t r e o f t h e ( c o v e r e d ) a c c e p t a n c e area o f t h e photometer head. I f t h e laser i s t u r n e d around t h e v e r t i c a l a x i s t h e p o s i t i o n of t h e beam i n t h e p l a n e o f t h e a c c e p t a n c e area s h o u l d n o t change.

For c h e c k i n g t h e p o s i t i o n of t h e h o r i z o n t a l a x i s a t h i c k a weight a t t h e bottom is f i x e d t o t h e v e r t i c a l a x i s . I f t h e place o f t h e photometer head and i t s beam h i t s t h e h o r i z o n t a l a x i s is l o c a t e d where t h e beam remains at t h e s t r i n g when t h e h o r i z o n t a l a x i s is t u r n e d .
1 3 . 3 GONIOPHOTOMETER WITH ROTATING MIRROR

white s t r i n g with a laser i s p u t i n s t r i n g , then t h e same s p o t on t h e

In o r d e r t o c h e c k t h e a d j u s t m e n t of t h e goniophotometer w i t h a r o t a t i n g m i r r o r a measuring s h a f t is i n s e r t e d i n t h e r e c e p t a c l e f o r t h e l i g h t s o u r c e , which c o n t a i n s t h e vertical a x i s and which has a d i a m e t e r o f a few millimeters at t h e point o f i n t e r s e c t i o n o f t h e axes ( l o c a t i o n o f t h e photometric c e n t r e ) . The p o s i t i o n of t h e p h o t o m e t r i c c e n t r e is marked on i t . The photometer head is r e p l a c e d by a l a s e r , w i t h its beam a f t e r ref l e c t i o n from t h e m i r r o r b e i n g d i r e c t e d a t t h e p h o t o m e t r i c c e n t r e f o r any mirror position. By means o f a n a p e r t u r e p l a c e d n e a r t h e mirror t h e d i a m e t e r of t h e l a s e r beam s h o u l d b e r e s t r i c t e d t o less t h a n 10 mm. When t u r n i n g t h e m i r r o r t h e l a s e r beam s h o u l d h i t t h e p h o t o m e t r i c c e n t r e independent o f t h e mirror position.

14. CALIBRATION

Goniophotometers c a n be c a l i b r a t e d by means o f a luminous i n t e n s i t y s t a n d a r d lamp. A l t e r n a t i v e l y , t h e i l l u m i n a n c e meter (luminance i n t e g r a t o r ) i s c a l i b r a t e d and t h e d i s t a n c e between t h e p o i n t o f i n t e r s e c t i o n o f t h e axes and t h e a c c e p t a n c e a r e a is measured. For g o n i o p h o t o m e t e r s w i t h r o t a t i n g mirror t h e f i r s t method i n c l u d e s t h e p r o p e r t i e s o f t h e m i r r o r . 35

~-

CIE 70 8 7
14.1 LUMINOUS INTENSITY STANDARD

9006L45 0003063 757

The luminous i n t e n s i t y s t a n d a r d lamp is mounted w i t h i t s p h o t o m e t r i c centre a t t h e point o f i n t e r s e c t i o n o f t h e axes i n t h e p r e s c r i b e d burning p o s i t i o n i n such a way t h a t t h e luminous i n t e n s i t y i s measured i n t h e d i r e c t i o n f o r which t h e lamp is c a l i b r a t e d . From t h i s f o l l o w s t h e

r e l a t i o n s h i p between luminous i n t e n s i t y and r e a d i n g .
14.2 CALIBRATED ILLUMINANCE METER

The i l l u m i n a n c e meter is c a l i b r a t e d on a p h o t o m e t r i c bench and t h e d i s t a n c e between t h e p o i n t o f i n t e r s e c t i o n of t h e a x e s and t h e measuring a r e a i s measured. From these d a t a it i s p o s s i b l e t o c a l c u l a t e t h e luminous i n t e n s i t y a c c o r d i n g t o t h e p h o t o m e t r i c d i s t a n c e law. For a photometer head w i t h luminance i n t e g r a t i o n no d i s t a n c e measurement is r e q u i r e d i f i t h a s been e s t a b l i s h e d t h a t t h e r e a d i n g is independent o f t h e d i s t a n c e . 14.3 RELATIVE MEASUREMENTS For t h e measurement o f t h e r e l a t i v e luminous i n t e n s i t y d i s t r i b u t i o n The l i n e a r i t y o f t h e photo[2,3,4] no s p e c i a l c a l i b r a t i o n is r e q u i r e d , meter must be i n s u r e d .

15. ERROR SOURCES AND MEASUREMENT ACCURACY

15.1 MECHANICAL ARRANGEMENT
The f o l l o w i n g mechanical d e f e c t s can c a u s e measuring e r r o r s :

-

i n s u f f i c i e n t mechanical s t a b i l i t y h o r i z o n t a l and v e r t i c a l a x i s do n o t i n t e r s e c t t h e two axes are n o t p e r p e n d i c u l a r t o each o t h e r w i t h g o n i o p h o t o m e t e r s w i t h r o t a t i n g m i r r o r , t h e o p t i c a l a x i s o f mirror and t h e r o t a t i n g axis o f t u r n t a b l e do n o t c o i n c i d e v i b r a t i o n o f moveable p a r t s d u r i n g r o t a t i o n wrong p o s i t i o n i n g o f t h e photometer head uneven r o t a t i o n due t o v i b r a t i o n s o r l a c k o f b a l a n c i n g .

-

36

~~~

~~

~~~

CIE 70 8 7

9006345 O003064 6 9 3 S

15.2 ANGLE MEASUREMENTS A D ANGULAR STEP S I Z E N
The accuracy o f luminous i n t e n s i t y measurements depends t o a l a r g e ext e n t on t h e measurement u n c e r t a i n t y f o r angle measurements and t h e angular step s i z e . The measurement u n c e r t a i n t y depends e s s e n t i a l l y on t h e k i n d o f angle encoder used, I n f o r m a t i o n about t h i s aspect should be o b t a i n e d f r o m t h e manufacturers. For a known luminous i n t e n s i t y d i s t r i b u t i o n t h e measurement u n c e r t a i n t y i n t h e luminous i n t e n s i t y caused by t h i s aspect can be calculated.

If h e goniophotometer i s n o t stopped a t each angular p o s i t i o n (angles x , y ) t t o perform a measurement, each measured v a l u e w i l l be t h e mean over an angular i n t e r v a l t h a t depends on t h e measuring t i m e and t h e speed o f r o t a t i o n of t h e moveable p a r t s . u n c e r t a i n t y are: F a c t o r s i n f l u e n c i n g t h e r e s u l t i n g measurement

-

mechanical u n c e r t a i n t i e s w i t h angle measurements angular u n c e r t a i n t i e s d u r i n g t h e i n t e g r a t i o n time, e s p e c i a l l y f o r AC powered l i g h t sources t h e time i n t e r v a l r e q u i r e d f o r one sample t h e t i m e i n t e r v a l between two successive angle steps. INFLUENCE

75.3

O F

ROTATING

MIRROR

OR

PHOTDMETER

HEAD

FOR

LUMINANCE

INTEGRATION
The m i r r o r used i n goniophotometers w i t h r o t a t i n g m i r r o r s d e v i a t e s i n its p r o p e r t i e s from an i d e a l m i r r o r . Measuring e r r o r s caused by t h e m i r r o r can have t h e f o l l o w i n g causes:

-

d e v i a t i o n o f t h e m i r r o r surface From a p l a n e and t h e change o f t h i s dev i a t i o n during r o t a t i o n l o c a l changes o f t h e r e f l e c t a n c e o f t h e m i r r o r l i g h t s c a t t e r i n g on t h e m i r r o r surface due t o d i f f u s e r e f l e c t i o n , damaged m i r r o r s u r f a c e or dust

-

-

p o l a r i z a t i o n o f t h e l i g h t t o be measured a t t h e m i r r o r s u r f a c e wavelength dependence o f t h e r e f l e c t a n c e o f t h e m i r r o r s u r f a c e i n s u f f i c i e n t plane p a r a l l e l i t y of mirrors ( l e n s e f f e c t s ) .

-

t h e s u b s t r a t e g l a s s for r e a r c o a t e d

37

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CIE ? O ? ? I700bL45 00030b5 5 2 T I
4 p o l a r i z a t i o n e r r o r caused by t h e mirror [ 2 4 ] c a n sometimes be e l i m i n a t e d by means o f an a n a l y s e r p l a c e d i n f r o n t of t h e photometer head, which moves w i t h t h e mirror. The e r r o r caused by t h e l i g h t s c a t t e r e d from a c l e a n rot a t i n g m i r r o r is d i f f i c u l t t o e l i m i n a t e . However, f o r a l a r g e measuring d i s t a n c e and a good mirror i t is u s u a l l y n e g l i g i b l e .
The e r r o r due t o t h e d e v i a t i o n o f t h e m i r r o r s u r f a c e from a p l a n e ( s u r f a c e

roughness) c a n n o t be e l i m i n a t e d . lection o f t h e m i r r o r .

I t can be made n e g l i g i b l e by c a r e f u l se-

I t is p o s s i b l e t o e l i m i n a t e t h e error caused by t h e selective s p e c t r a l ref l e c t i o n o f t h e m i r r o r s u r f a c e by f i t t i n g t h e r e l a t i v e s p e c t r a l r e s p o n s e o f t h e photometer head p l u s t h e m i r r o r t o t h e V ( X > f u n c t i o n .
F o r photometer heads with l u m i n a n c e i n t e g r a t i o n , e r r o r s . can b e caused by:

-

non-constant s p a t i a l r e s p o n s e i n s u f f i c i e n t s i z e o f t h e a c c e p t a n c e area i n s u f Ficient d i s t a n c e between l i g h t s o u r c e and a c c e p t a n c e a r e a , c a u s i n g some p a r t s o f t h e l i g h t s o u r c e t o b e missed t o o l a r g e a measuring-field a n g l e , causing t h e c o n d i t i o n o f t h e l i m i t i n g p h o t o m e t r i c d i s t a n c e t o be v i o l a t e d .

-

-

15.4 STRAY L I G H T

Stray l i g h t c a n i n v a l i d a t e t h e r e s u l t o f measurements o f luminous intensity distributions. T h e r e f o r e i t is recommended t o use b a f f l e s between t h e l i g h t s o u r c e and t h e a c c e p t a n c e a r e a of t h e photometer head t h a t limit t h e i n c i d e n c e o f stray l i g h t b u t do not cause v i g n e t t i n g i n t h e beam
path.

I t is p o s s i b l e t o d e t e r m i n e t h e p r o p o r t i o n o f t h e s t r a y l i g h t by p l a c i n g a s c r e e n o f t h e smallest p o s s i b l e d i m e n s i o n , t h a t e l i m i n a t e s t h e d i r e c t
i n c i d e n c e o f l i g h t from t h e l i g h t s o u r c e on t h e a c c e p t a n c e a r e a , a p p r o x i The m a t e l y halfway between t h e l i g h t s o u r c e and t h e photometer head. measurement o f t h e l u m i n o u s i n t e n s i t y d i s t r i b u t i o n s h o u l d be r e p e a t e d w i t h t h i s screen i n p l a c e . The measured s i g n a l is t h e n due t o t h e i n c i d e n c e of s t r a y l i g h t and t h i s amount s h o u l d be s u b t r a c t e d from t h e measurement made w i t h o u t t h e screen. (See also [ 251 ).

38

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C I E 7 0 87 W 9006345 00030bb Ybb

15.5 RELATIVE SPECTRAL

RESPONCIVITY

The r e l a t i v e s p e c t r a l r e s p o n s i v i t y o f t h e photometer head u s e d s h o u l d be f i t t e d very a c c u r a t e l y t o t h e s p e c t r a l luminous e f f i c i e n c y V ( X ) o f t h e human eye f o r p h o t o p i c v i s i o n 1,6,7]. I f t h e l i g h t s o u r c e t o be measured h a s t h e same s p e c t r a l d i s t r i b u t i o n as t h e c a l i b r a t i o n s t a n d a r d t h e q u a l i t y o f t h e V ( X ) f i t is n o t i m p o r t a n t . T h i s c a n b e t h e case, f o r example, i n r e l a t i v e measurements. For a goniophotometer with r o t a t i n g m i r r o r t h e V ( X ) f i t o f t h e photometer head should be made i n c o n j u n c t i o n with t h e mirror. For photometer h e a d s f o r luminance i n t e g r a t i o n one s h o u l d pay a t t e n t i o n t o t h e f a c t t h a t t h e r e l a t i v e s p e c t r a l r e s p o n s e may change due t o d i r t (even The meacurei f i t is n o n - s e l e c t i v e ) i f a c a v i t y is used f o r i n t e g r a t i o n . ment of t h e r e l a t i v e s p e c t r a l r e s p o n s e for t h e s e photometer heads i s always p o s s i b l e for t h e d e t e c t o r used but n o t g e n e r a l l y f o r t h e complete photometer head.

15.6 ILLUMINANCE AND LUMINANCE METER

The photometer head w i t h t h e a t t a c h e d p h o t o e l e c t r o n i c s d e t e r m i n e s t h e measurement accuracy t o a l a r g e e x t e n t . S p e c i f i c a t i o n s and e r r o r limits for t h e measurement a c c u r a c y have been corrpiled i n C I E p u b l i c a t i o n s

CI W.
15.7 DATA PROCESSING

For t h e a c q u i s i t i o n and p r o c e s s i n g o f t h e measurement d a t a t h e errors w i t h t h e d i g i t a l s i g n a l s w i l l u s u a l l y be n e g l i g i b l e . If t h e d a t a are acq u i r e d i n an a n a l o g way e r r o r s due t o t h e i n s t r u m e n t s used s h o u l d be t a k e n i n t o account.
15.8 LIMITING PHOTOMETRIC DISTANCE Errors depending on t h e luminous i n t e n s i t y d i s t r i b u t i o n can b e c a u s e d by t o o small a d i s t a n c e between t h e l i g h t s o u r c e and t h e photometer head. Examples o f e r r o r c a l c u l a t i o n s a r e g i v e n i n t h e l i t e r a t u r e [9,10].
15.9 OPERATING CONDITIONS

Errors can be c a u s e d by o p e r a t i n g c o n d i t i o n s d e v i a t i n g f r o m p r e s c r i b e d c o n d i t i o n s . They a r e :

-

p o s i t i o n i n g o f t h e p h o t o m e t r i c centre i n a p o s i t i o n d e v i a t i n g f r o m t h e p o i n t o f i n t e r s e c t i o n o f t h e two axes

39

C I E 70 87

9006345 0003067 3T2

=

d e v i a t i o n of t h e o r i e n t a t i o n of t h e l i g h t s o u r c e from t h e p r e s c r i b e d burning p o s i t i o n . T h i s i n f l u e n c e can b e c o r r e c t e d f o r only very inaccur a t e l y i n t h e c a s e o f goniophotometers w i t h a d e v i c e for t u r n i n g t h e l i g h t source
s t a r t of t h e measurements b e f o r e t h e end of t h e burn-in warm-up p e r i o d

period or t h e

i n a c c u r a t e a d j u s t m e n t and measurement o f t h e o p e r a t i n g v o l t a g e o f the 1i ght source d e v i a t i o n o f t h e mains f r e q u e n c y from t h e p r e s c r i b e d f r e q u e n c y varying c o n t a c t r e s i s t a n c e o f t h e s l i p r i n g s n o n - p e r m i s s i b l e harmonics c o n t e n t of t h e s u p p l y v o l t a g e d e v i a t i o n o f t h e ambient t e m p e r a t u r e from t h e p r e s c r i b e d value t e m p o r a l i n s t a b i l i t y o f t h e l i g h t s o u r c e t o be measured d r a u g h t by means of v e n t i l a t i o n equipment o r t o o f a s t movement o f t h e l i g h t source s c r e e n i n g o f p a r t s o f t h e l i g h t s o u r c e by mechanical goniophotometer o r by b a f f l e s i n t h e l i g h t path. parts of the

15.10

PHOTOMETRIC STANDARD

The p h o t o m e t r i c d a t a o f t h e s t a n d a r d used i n t h e c a l i b r a t i o n are s u b j e c t t o a measurement u n c e r t a i n t y . The v a l u e o f t h e u n c e r t a i n t y o f t h e s t a n d a r d s h o u l d b e t a k e n f r o m t h e c a l i b r a t i o n c e r t i f i c a t e and s h o u l d be s t a t e d when g i v i n g error limits f o r t h e measurements. Additional errors a r e p o s s i b l e through t h e i n a c c u r a t e s e t t i n g o f t h e electrical o p e r a t i n g c o n d i t i o n s f o r t h e photometric s t a n d a r d d u r i n g c a l i b r a t i o n .

16. CHARACTERIZATION O f GONIOPHOTOHETERS

16.1 MECHANICAL ARRANGEMENTS

I n o r d e r t o c h a r a c t e r i z e t h e mechanical d e t a i l s of a goniophotometer t h e f o l l o w i n g d a t a s h o u l d be s u p p l i e d :

-

t y p e o f goniophotometer

40

-

g e o m e t r i c a l dimensions p e r m i s s i b l e t o t a l weight o f t h e l i g h t s o u r c e p e r m i s s i b l e maximum d i m e n s i o n s o f t h e l i g h t s o u r c e a n g u l a r i n t e r v a l o v e r which t h e luminous i n t e n s i t y can be measured without s c r e e n i n g by p a r t s o f t h e i n s t r u m e n t measuring d i s t a n c e between l i g h t source and photometer head.

-

-

F o r goniophotometers w i t h r o t a t i n g m i r r o r s :

-

d a t a on t h e q u a l i t y o f t h e m i r r o r .

16.2 ANGLE ENCODING

I n o r d e r t o c h a r a c t e r i z e t h e i n s t r u m e n t s used f o r a n g l e encoding t h e f o l l o w i n g i n f o r m a t i o n is r e q u i r e d :

-

t y p e of a n g l e e n c o d i n g resolution t y p e o f z e r o encoding p o s s i b l e d e v i a t i o n s between t h e measured and t h e true a n g l e s .

1 6 . 3 PHOTOMETER HEAD
The p r o p e r t i e s o f t h e photometer head s h o u l d be stated i n a c c o r d a n c e w i t h t h e relevant C I E recommendations -[61. For photometer heads w i t h l u m i nance i n t e g r a t i o n t h e d a t a a c c o r d i n g t o s e c t i o n 3 . 2 s h o u l d be added.

16.4 PHOTOELECTRONICS AND DATA PROCESSING
I n o r d e r t o c h a r a c t e r i z e t h e p h o t o e l e c t r o n i c s and d a t a p r o c e s s i n g t h e information i n accordance with t h e relevant C I p u b l i c a t i o n s [ I , 6 ] should be s u p p l i e d . I n a d d i t i o n t h e f o l l o w i n g s h o u l d be s t a t e d :

-

t h e i n t e g r a t i o n i n t e r v a l for t h e illuminance integration.

41

1)

-

Methods o f c h a r a c t e r i z i n g t h e performance radiometers and photometers P u b l i c a t i o n C I E No. 53 (TC-2.2) 1982

of

2)

-

Photometry o f indoor t y p e l u m i n a i r e s with t u b u l a r f l u o r escent lamps P u b l i c a t i o n C I E No. 24 (TC-2.4) 1973 Photometry of Luminaires f o r S t r e e t L i g h t i n g P u b l i c a t i o n CIE No. 27 (IC-2.4) 1973 Photometry of f l o o d l i g h t s P u b l i c a t i o n s C I E No. 43 (TC-2.4) 1979 I n t e r n a t i o n a l l i g h t i n g vocabulary, 3 r d ed, P u b l i c a t i o n CIE No. 17 (E-1.1) 1970 Methods o f c h a r a c t e r i z i n g i l l u m i n a n c e meters and 1 uminance met ers P u b l i c a t i o n CIE (TC-2.2) t o be p u b l i s h e d The b a s i s o f p h y s i c a l photometry P u b l i c a t i o n CIE No. 18.2 (TC-1.2) 1983 Photometry o f l u m i n a i r e s P u b l i c a t i o n C I E ( D i v i s i o n 11) t o be p u b l i s h e d
II

3)

-

4)

5)

6)

7)

H.J.
Hentschel

8)

9)

Uber den E i n f l u ? 3 der L i c h t s t ? r k e v e r t e i l u n g a u f d i e photometrische Grenzentfernung L i c h t t e c h n i k 12 (1960) p. 673-674

IO) Y.

Ctolzenberg

D i e Kennzeichnung und Messung d e r L i c h t s t a r k e v e r t e i l u n g von Leuchten f ü r L e u c h t s t o f f l a m p e n Tagungsbericht Fachtagung LiTG, SLG, LTAG Salzburg, Ed. 1, p. 238-256
Low-reflectance b a c k i n g m a t e r i a l s f o r use i n o p t i c a l r a d i a t i o n measurement Color Res. and Appl. 6 (1981) p. 139-142 Zero-length s e a r c h l i g h t photometry system I l l u m i n a t i n g E n g i n e e r i n g 57 (1962) p. 187-194

11) T.E.

Wightman

F. Grum

12) J Johnson

42

CIE 70 8 7

9006345 0003070 797

1 3 ) F . Languasca M. Pasta P. Soardo

Photometry o f photometer

luminaires at

IEN:

A new gonio-

P u b l i c a t i o n C I E No. 50 (1980) p. 180-183

14) E. Frederiksen

U n i d i r e c t i o n a l - s e n s i t i v e photometer L i g h t and L i g h t i n g 60 (1967) p. 46-48

1 5 ) E . Frederiksen

The c o l l i m a t e d l i g h t photometer Report No. 28, L y s t e k n i s k Laboratorium, Kopenhagen 1981 A p p a r e i l s modernes de photometrie e t de c o l o r i met r i e LUX (1979) 102, p. 109-118 Lichtmessung, Messungen an Leuchten D I N 5032 T e i l 4 Goniophotometry, methods and performance Proceedings of t h e symposium on " L i g h t and Radiat i o n Measurement '!I", p. 20-38 Hungarian E l e c t r . Assoc. Budapest 1981 A automated high-speed photometer n Journ. I E S 6 (1977) N r . 2, p. 105-109 Luminous f l u x measurements a t t h e NPRL by means o f a new goniophotometer. Proc, 10th IMEKO Symp. Photon-Detectors, Berlin, 1982 p. 205-214 IMEKO S e c r e t a r i a t H 1374 Budapest PO8 457

16) J. Krochmann

17)

J. Krochmann

18

19) L.C. Snyder P.E. Westlake
20) L.A.G. Monard F. Hengstberger T . Appenroth M.E. Thain C.J. Kok R . Turner 21) Y. Kurioka

L i g h t d i s t r i b u t i o n photometry i n Japan. App. O p t i c s 10 (1971) No. 12, p. 2600-2606. Mésures é l e c t r i q u e s s u r l e s lampes a décharge Courant) (Puissance - Tension Revue E (Belgium) V o l 4 Nr. 8 (1964) p. 311-327

22) C . Morren

-

23) U. Mathis

Anwendung von e l e k t r o n i s c h e n V o r s c h a l t g e r ? t e n für Leuchtstofflampen

Tagunqsbericht LTAG Fachtagung Graz, 1983

43

~~

~~

~~

CIE 70 87
24) M. Nonaka

9006345 0003071 823

Polarisation e r r o r s in distribution measurements o f luminaires Journal o f the II1.Eng.Inst. o f Japan, 56 (1972) p . 537-545 Elimination des Fremdlichtes bei der tichtstrombestimmung m i t dem Goniophotometer Licht-Forschung 2 (1980), p. 27-29

25) D. F?rste C. Sauter H. Martin

44


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