Iec 62595 2 1 2016

IEC 62595 2 1 Edition 1 0 201 6 04 INTERNATIONAL STANDARD Display l ighting unit – Part 2 1 Electro optical measuring methods of LED backlight unit IE C 6 2 5 9 5 2 1 2 0 1 6 0 4 (e n ) ® colour ins i[.]

IEC 62595-2-1

Editio 1.0 2 16-0

Display l ghting unit –

Part 2-1: Electro-optical measuring methods of LED back light unit

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IEC 62595-2-1

Editio 1.0 2 16-0

Display l ghting unit –

Part 2-1: Electro-optical measuring methods of LED back light unit

INT R A TIONAL

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CONTENTS

FOREWORD 3

1 Sco e 5

2 Normative referen es 5

3 Terms, definition an a breviation 5

3.1 Terms an definition 5

3.2 Ab reviation 5

4 General me s rement con ition 5

4.1 Stan ard atmospheric con ition for LED BLU 5

4.2 Me s rin setup 6

4.3 Warm-up time 6

5 Me s rement method 7

5.1 Electrical me s rement method 7

5.1.1 Con ition 7

5.1.2 Cur ent 7

5.1.3 Voltage 7

5.1.4 Power con umption 7

5.2 Optical me s rement method 7

5.2.1 Con ition 7

5.2.2 Luminan e 8

5.2.3 Luminan e u iformity or non-u iformity 9

5.2.4 Sp ctral p wer distribution 10 5.2.5 Chromaticity 10 5.2.6 Colour u iformity 10 5.2.7 An ular luminan e u iformity 1

5.2.8 An ular colour u iformity 1

5.2.9 Me s rement method of block-wise BLUs 1

Bibl ogra h 16 Fig re 1 – Example of me s rin setup for LED BLU 6

Fig re 2 – Example of warm-up c aracteristic of BLU 7

Fig re 3 – Definition of zenith an le θ an azimuth an le ϕ 8

Fig re 4 – Examples of me s rement p int layout 10 Fig re 5 – An ular luminan e u iformity me s rement 1

Fig re 6 – Example of c eck rb ard p t ern (8 segments × 10 segments) for bl

ock-wise BLU 12

Fig re 7 – Example of sin le block white p t ern 12

Fig re 8 – Example of sin le block black p t ern 13

Fig re 9 – Example of in oherent p int spre d fu ction 13

INTERNATIONAL ELECTROTECHNICAL COMMISSION

DISPLAY LIGHTING UNIT –

Part 2-1: Electro-optical measuring methods

of LED backl ght unit

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International Stan ard IEC 6 5 5-2-1 has b en pre ared by IEC Tec nical Commite 1 0:

Electronic display devices

This first edition can els an re laces the first edition of IEC 6 5 5-2 publ s ed in 2 12 This

edition con titutes a tec nical revision

This edition in lu es the fol owin sig ificant tec nical c an es with resp ct to the previou

edition:

a) c an ed the series title in order to cover frontl g t u it;

b) ad ed the detai ed me s rement proced res p rtic larly for block-wise BLU;

c) deleted An ex A;

The text of this stan ard is b sed on the fol owin doc ments:

Ful information on the votin for the a proval of this stan ard can b fou d in the re ort on

votin in icated in the a ove ta le

This publcation has b en drafed in ac ordan e with the ISO/IEC Directives, Part 2

A l st of al p rts in the IEC 6 5 5 series, publ s ed u der the general title D ispla lghtn

uni, can b fou d on the IEC we site

Future stan ard in this series wi car y the new general title as cited a ove Titles of existin

stan ard in this series wi b updated at the time of the next edition

The commit e has decided that the contents of this publcation wi remain u c an ed u ti

the sta i ty date in icated on the IEC we site un er "htp:/we store.iec.c " in the data

related to the sp cific publ cation At this date, the publ cation wi b

• reconfirmed,

• with rawn,

• re laced by a revised edition, or

• amen ed

A bi n ual version of this publ cation may b is ued at a later date

IMPORTANT – The 'colour in ide' logo on the cov r pa e of this publ c tion indic te

that it contains colours whic are consid re to be u eful for the cor e t

understa ding of its conte ts Us rs s ould therefore print this doc me t using a

colour printer

DISPLAY LIGHTING UNIT –

Part 2-1: Electro-optical measuring methods

of LED backl ght unit

This p rt of IEC 6 5 5 sp cifies the stan ard me s rement con ition an me s rin

method for determinin the electrical an o tical p rameters of LED b ckl g t u its for l q id

cry tal display

The folowin doc ments, in whole or in p rt, are normatively referen ed in this doc ment an

are in isp n a le for its a pl cation For dated referen es, only the edition cited a pl es For

u dated referen es, the latest edition of the referen ed doc ment (in lu in an

amen ments) a pl es

IEC 617 7-3 -1, Liquid crystal disp la de vice s – Part 30 -1: Me surin meth ds for lquid

crystal displa modules – Tra smis iv ty e

IEC 6 5 5-1-2, D ispla lghtn u ni – Part 1-2: Termin logy a d lete r symb ols

1

3 Terms, definitions and a bre iations

3.1 Terms a d definitions

For the purp ses of this doc ment, the terms an definition given in IEC 6 5 5-1-2 a ply

3.2 Abbre iations

BLU b ckl g t u it

FOV field of view

LMD l g t me s rin device

LSF l g t spre d fu ction

4 General measurement conditions

4.1 Sta dard atmosph ric conditions for LED BLU

Unles otherwise sp cified, al tests an me s rements for LED BLU s al b car ied out af er

s f icient warm-up time (se 4.3), u der the stan ard en ironmental con ition , at a

temp rature of 2 °C ± 3 °C, a relative h midity of 2 % to 8 %, an an atmospheric

pres ure of 8 kPa to 10 kPa When dif erent en ironmental con ition are u ed, they s al

b noted in the detai sp cification (se IEC 617 7-3 -1)

_ _ _ _ _ _ _

4.2 Me s ring s tup

Fig re 1 s ows a typical setup of a BLU, luminan e meter, p wer source, block controler,

voltmeters an c r ent meters for electro-o tical me s rements for LED BLU

Figure 1 – Ex mple of me s rin s tup for LED BLU

4.3 Warm-up time

The luminan e of LED b ckl g ts is af ected by the tran ient temp rature b haviour of LED

output as in Fig re 2 It ta es a certain time for LEDs u ti their ju ction temp rature re c es

the ste d state Luminan e me s rement s al b car ied out an recorded u ti the

flu tuation of luminan e me s red at an a pro riate p int (u ual y at the centre p int of the

BLU b come les than the ran e sp cified in IEC 617 7-3 -1 u les otherwise sp cified The

luminan e me s rement s al b car ied out as in 5.2.2 Al me s rin con ition s al b

k pt con tant d rin the me s rements

Chromaticity me s rement s al b car ied out in the same man er as in the a ove, unles

otherwise sp cified The c romaticity me s rement s al b car ied out as in 5.2.5

The a ove me s rements can b c stomized b twe n the c stomer an the s p l er,

LMD

(Luminan e meter )

BLU FOV

Power s p ly Block contr ol

sig al

(or block-w ise BLU)

BLU

Power s p ly Block contr ol

sig al

(or block-w ise BLU)

V I

I

V

V

BLU

I

LU

V

sg nal

I

si gna l

Sample stage

Ammeter I

V Voltmeter

IEC

Figure 2 – Ex mple of warm-up c ara teristic of BLU

5.1 Ele tric l me s reme t methods

5.1.1 Condition

The BLU s al b placed in the me s rement ar an ement an it s al b as ured that al

req ired con ition are fulfi ed

Afer a plyin the initial electrical drivin con ition (i.e analog e input voltage(s) or digital

input sig als) of the BLU an waitin d rin the warm-up time sp cified in 4.3 in order to

re c the ste d state, the me s rement of the electrical q antities of interest s al b started

5.1.2 Cur e t

The me s rement of input c r ent s ould be p rformed u der stan ard me s rin con ition

u in the c r ent meter s own in Fig re 1

5.1.3 Volta e

The me s rement of input voltage s ould b p rformed u der stan ard me s rin con ition

u in the voltage meter s own in Fig re 1

5.1.4 Power con umption

The me s rement of p wer con umption s ould b car ied out u der the stan ard me s rin

con ition in 4.1, u in a p wer meter, or calc lated by the me s red values of voltage an

c r ents in 5.1.2 an 5.1.3 For block-wise BLUs, the p wer con umption of the control sig al

s al b con idered

5.2 Optic l me s reme t method

5.2.1 Condition

The LED BLU to b me s red s ould b placed in the me s rement ar an ement an it s al

IEC

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

Time (min)

Afer a plyin the initial electrical drivin con ition to the BLU an waitin d rin the warm

-up time sp cified in 4.3 in order to re c the ste d state, the me s rement of the o tical

q antities of interest s al b started The me s rement of this stan ard s ould b car ied

out at variou an les b twe n the BLU an the LMD A p lar co rdinate s stem (θ,ϕ), with

the zenith denoted by θ an the azimuth denoted by ϕ s ould b con idered (se Fig re 3)

Figure 3 – Definition of ze ith a gle θ a d azimuth a gle ϕ

5.2.2 Lumina c

The me s rements s ould b car ied out in the dark ro m u der the stan ard me s rin

con ition an for the desig viewin direction , as fol ows:

a) Position the BLU

b) Adju t the LMD to the sp cified viewin direction, ac ordin to an les θ an ϕ

c) Sup ly the value of the input sig als to the BLU Then me s re the BLU at p sition p

i

to

o tain the luminan e L

vi (θ,ϕ) (In case of i = 0, the p sition impl es the centre of the

active are of the BLU.)

The LMD s ould b careful y c eck d b fore me s rements, con iderin the folowin

elements:

• sen itivity of the me s red q antity to the me s rin lg t;

• er ors cau ed by vei n glare an len flare (i.e stray lg t in an o tical s stem);

• timin of data-ac uisition, low-p s fi terin an al asin -efects;

• l ne rity of detection an data-con ersion;

• me s rement size an field of view (FOV)

To en ure luminan e ac urac for the intended LED sources, a bro d b n width LMD s ould

b cal brated u in a sp ctrometer with a b n width 5 nm or les

The luminan e of BLU s ould b me s red by s n hronizin the LMD with the BLU refres

x y

z

φ

θ

LMD

BLU

12:0

9:0

6:0

3:0

IEC