Iec 62715 5 1 2017

4 An ex A informative Calc lation method of ambient colour gamut volume.. FLEXIBLE DISPLAY DEVICES – Part 5-1: Measuring methods of optical perf ormance This p rt of IEC 6 715 sp cifies

IEC 6271 5- 5- 1

Editio 1.0 2 17-0

Flex ible display devices –

Part 5- 1: Measuring met hods of opt ical per ormance

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IEC 6271 5- 5- 1

Edit io 1.0 2 17-0

Flex ible display devices –

Part 5- 1: Measuring met hods of opt ical per ormance

FOREWORD 5

INTRODUCTION 7

1 Sco e 8

2 Normative ref eren es 8

3 Terms, def i ition an a breviated terms 8

3.1 Terms an def i ition 8

3.2 Ab reviated terms 9

4 Stru ture of me s rin eq ipment 9

4.1 Me s rin con g ration – Display mou tin 9

4.1.1 General 9

4.1.2 Display mou tin for u iformity me s rements 10 4.1.3 Display mou tin for viewin direction me s rements 10 4.2 Lig t me s rin device 1

4.3 Lig t source config ration 13 4.3.1 General 1

3 4.3.2 Uniform hemispherical dif fu e i umination 13 4.3.3 Directed source i umination 14 5 Stan ard me s rin con ition 15 5.1 Stan ard me s rin en ironmental con ition 1

5 5.2 Stan ard l g tin con ition 15 5.2.1 Dark ro m con ition 15 5.2.2 Stan ard ambient i umination sp ctra 15 5.2.3 Stan ard i umination ge metries 17 5.2.4 Dif fu e ref lectan e stan ard 17 5.3 Stan ard setup con ition 17 5.3.1 Adju tment of display mod les 17 5.3.2 Startin con ition of me s rements 17 5.3.3 Con ition of me s rin eq ipment 18 5.4 Stan ard location of me s rement field 18 6 Optical me s rin method in dark ro m con ition 18 6.1 Luminan e an its u if ormity 18 6.1.1 General 18 6.1.2 Me s rin eq ipment 19 6.1.3 Scre n centre luminan e me s rin method 19 6.1.4 Luminan e u iformity me s rin method 19 6.1.5 Luminan e u iformity def i ition an evaluation 2

6.2 Contrast ratio 2

6.2.1 General 2

6.2.2 Me s rin eq ipment 2

6.2.3 Me s rin method 2

6.2.4 Definition an evaluation 2

6.3 Chromaticity, colour u iformity, an colour gamut are 21

6.3.1 General 21

6.3.2 Me s rin eq ipment 21

6.3.3 Scre n centre c romaticity me s rin method 21

6.3.5 Colour u if ormity me s rin method 2

6.4 Pe k white field cor elated colour temp rature 2

6.4.1 General 2

6.4.2 Me s rin eq ipment 2

6.4.3 Me s rin method 2

6.5 Viewin direction de en en e 2

6.5.1 General 2

6.5.2 Me s rin eq ipment 2

6.5.3 Me s rin method 2

6.5.4 Definition an evaluation 2

6.6 Cros -talk with display in b nt state 2

6.6.1 General 2

6.6.2 Me s rin eq ipment 2

6.6.3 Me s rin method 2

7 Optical me s rin method u der ambient i umination 31

7.1 Reflection me s rements 31

7.1.1 General 31

7.1.2 Me s rin con ition 3

7.2 Ambient contrast ratio 3

7.2.1 General 3

7.2.2 Me s rin con ition 3

7.2.3 Me s rin method 3

7.3 Ambient display colour 3

7.3.1 General 3

7.3.2 Me s rin con ition 3

7.3.3 Me s rin method 3

7.4 Ambient colour gamut volume 3

7.4.1 General 3

7.4.2 Me s rin con ition 3

7.4.3 Me s rin method 3

7.4.4 Re ortin 4

An ex A (informative) Calc lation method of ambient colour gamut volume 4

A.1 Purp se 4

A.2 Proced re f or calc latin the colour gamut volume 4

A.3 Sur ace s bdivision method f or CIELAB gamut volume calc lation 4

A.3.1 Purp se 4

A.3.2 As umption 4

A.3.3 Algorithm 4

A.3.4 Sof tware example exec tion 4

Biblogra h 4

Fig re 1 – Example of the co rdinate s stem u ed for a con ex display of a con tant radiu of c rvature a out the y-axis 10 Fig re 2 – To view example of how a con ex display can b rotated within the me s rement f ield 10 Fig re 3 – To view example of display mou t that rotates in the x-z plane for viewin direction me s rements 1

Fig re 4 – Optical c aracteristic of a sp t photometer, colorimeter, or

Fig re 5 – Example of the relation hip b twe n me s rement field diameter an

in l nation an les 13

Fig re 6 – Example of eflection me s rement ge metries f or spherical i umination 14

Fig re 7 – Example of con ex display i uminated by a directed l g t source 14

Fig re 8 – Example of con ex display i uminated by a rin l g t source 15

Fig re 9 – Stan ard me s rement p sition 18

Fig re 10 – Test p t ern u ed f or 4 % are win ow me s rements 19

Fig re 1 – Examples of the colour gamut as re resented in two common c romaticity

diagrams 2

Fig re 12 – Example of contrast ratio de en en e on viewin direction 2

Fig re 13 – Cros -talk p tern with diagonal 4 % white win ow b xes on grey b c grou d 2

Fig re 14 – Cros -talk p tern with diagonal 4 % blac win ow b xes on grey b c grou d 3

Fig re 15 – Cros -talk p tern with p rpen ic lar 4 % white win ow b xes on grey b c grou d 3

Fig re 16 – Cros -talk p tern with p rpen ic lar 4 % blac win ow b xes on grey b c grou d 31

Fig re 17 – Example of the ran e in colours prod ced by a display 4

Fig re A.1 – Analy is f low c art for calc latin the colour gamut volume 4

Fig re A.2 – Gra hical re resentation of the colour gamut volume for sRGB in the CIELAB colour sp ce 4

Ta le 1 – Input sig als for CIELAB, CIE 19 1 an CIE 19 6 UCS colour gamut me s rements 2

Ta le 2 – Example of CIE 19 6 UCS c romaticity non-u iformity 2

Ta le 3 – Example format u ed f or re ortin viewin direction p rorman e 2

Ta le 4 – Eigen alues M 1 an M 2 for CIE daylg t Il uminants D5 an D7 3

Ta le 5 – An example of minimum colours req ired for gamut volume calc lation of a 3-primary 8-bit display 3

Ta le 6 – Me s red tristimulu values f or the minimum set of colours 41

Ta le 7 – Calc lated white p int in the dark ro m an ambient i umination con ition 41

Ta le 8 – Colour gamut volume in the CIELAB colour sp ce 41

Ta le A.1 – Tristimulu values of the sRGB primary colours 4

Ta le A.2 – Example of sRGB colour set re resented in the CIELAB colour sp ce 4

Ta le A.3 – Example of sRGB colour gamut volume in the CIELAB colour sp ce 4

INTERNATIONAL ELECTROTECHNICAL COMMISSION

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FLEXIBLE DISPLAY DEVICES –

Part 5-1: Measuring methods of optical perf ormance

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International Stan ard IEC 6 715-5-1 has b en pre ared by IEC tec nical commite 1 0:

Electronic display devices

The text of this International Stan ard is b sed on the f ol owin doc ments:

Ful inf ormation on the votin for the a proval of this International Stan ard can b f ou d in

the re ort on votin in icated in the a ove ta le

This doc ment has b en draf ted in ac ordan e with the ISO/IEC Directives, Part 2

A l st of al p rts of the IEC 6 715 series, publ s ed u der the general title F l ex ibl e d ispla

The commite has decided that the contents of this doc ment wi remain u c an ed u ti the

sta i ty date in icated on the IEC we site u der "htp:/ we store.iec.c " in the data related to

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

IMPORTANT – Th 'colour inside' logo on the cover pa e of this publ c tion indic te

that it contains colours whic are consid re to be us f ul f or the cor e t

und rsta din of its conte ts Us rs s ould theref ore print this doc me t usin a

colour printer

This p rt of IEC 6 715 was desig ed for the stan ardization of me s rin method an

detai ed setup con ition that are u ed to c aracterize the o tical p r orman e of flexible

display devices

The s r ace con ition and s a e of f lexible display can c an e de en in on the

a pl cation F r example, a smart watc may have a f i ed con ex display, a cel phone or TV

a f i ed con ave display, an a b n a le display may have either a con ave or con ex s a e

with a varia le radiu of c rvature Up to now, al of these display would u ual y b

c aracterized in their flat state However, sin e it is p s ible that mec anical stres in u ed

by b n in the display can c an e its o tical c aracteristic , the display s ould b me s red

in its desig ed b nt state This en ures that the display’s o tical p rf orman e is

re resentative of its inten ed a plcation This doc ment sp cif ies the neces ary con ition

an method to me s re the o tical p rf orman e of a display in a b nt state

FLEXIBLE DISPLAY DEVICES –

Part 5-1: Measuring methods of optical perf ormance

This p rt of IEC 6 715 sp cifies the stan ard me s rin con ition an me s rin method

f or determinin the o tical p rf orman e of flexible display in the dark or u der ambient

i umination This doc ment mainly a pl es to display mod les that are b n a le a out one

axis The display is me s red in a static mec anical state The me s rin method a ply to

monoc rome or colour display with a sin le radiu of c rvature of 3 mm or gre ter

The f ol owin doc ments are ref er ed to in the text in s c a way that some or al of their

content con titutes req irements of this doc ment For dated referen es, only the edition

cited a ples For u dated ref eren es, the latest edition of the ref eren ed doc ment (in lu in

an amen ments) a pl es

IEC 6 0 0-8 5, Int ern t ion l El ectrot ec nic l Vo a ul ary – P art 8 5: Lighting (avaia le at

<htp:/ www.electro edia.org>)

IEC 619 6-2-1, Mult imed ia syst ems a d e uipme t – Colo r measureme t a d ma a eme t

– Part 2-1: Col our ma a eme t – Defa lt RGB c l our sp c – sRGB

IEC 6 715-1-1, Fl exibl e d ispl ay d evic s – P art 1-1: Terminol og a d lett er symbols

IEC 6 3 1-6-2:2 15, Org nic light emitt ing d iode (OLED) d ispl ays – Part 6-2: Measuring

methods of visu l q ality a d ambie t p rorma c

IEC 6 6 9-3-1:2 14, El ectro ic p p r d ispla s – Part 3-1: Opt ic l me suring meth ds

IEC TR 6 7 8, Displ ay tec n lo ies – LCD, PDP a d OLED – Ov rview a d e plan t ion of

difere c s in t ermin log

3.2 Abbre iate terms

CCT cor elated colour temp rature

CIE Commis ion Internationale de l Eclairage (International Commis ion on

sRGB stan ard RGB colour sp ce as def i ed in IEC 619 6-2-1

4 Structure of measuring equipment

4.1 Me s rin conf ig ration – Displa mounting

sp cific b n a le, f olda le an /or c rved c aracteristic of the f lexible display in its inten ed

u e con g ration The mou t s ould b ca a le of maintainin the inten ed s a e of the

display an locate it in the req ired me s rement p sition an viewin direction For c rved

display , these me s rin method only a ply for display that have a con tant radiu of

c rvature a out a sin le axis (e.g c l n rical s a e) Fig re 1 i u trates the co rdinate

s stem f or a con ex display that is c rved a out the y-axis The origin of the co rdinate

s stem is p sitioned at the imagin s r ace of the display an centred on the s re n The

same co rdinate s stem a pl es for a con ave display with the image ren erin s rf ace

facin the p sitive z-axis

For flat display , the image ren erin plane is al g ed in the x-y plane A f olda le display that

contain flat are s con ected by a nar ow region with a s ort radiu of c rvature s al b

me s red in the f lat are s, an tre ted as a f lat display

Unles otherwise sp cif ied, the o tical axis of the LMD s al b alg ed to within 1° of the

display s rf ace normal at the centre of the me s rement field in order to minimize the

al g ment er or introd ced by the display c rvature For sp t typ LMDs, the retro- eflection

of the LMD can b u ed to o tain this al g ment Otherwise, an al g ment laser can b u ed

to en ure that the LMD o tical axis p s es throu h a c rved display’s centre of c rvature

The method also as ume that the rotation stages an mec anical mou tin have s f ficient

ac urac an sta i ty to maintain a < 1° toleran e for an rotational or ti t motion

_ _ _ _ _ _

NOT Th origin is c ntre o th s re n whic is c rv d with a c n ta t ra iu r at th s rf ac of th ima in

pla e

Figure 1 – Ex mple of the coordinate s stem u e for a conv x displa of a

consta t ra ius of c rv ture about the y-a is

4.1.2 Displa mounting for unif ormity me s reme ts

For flat display , the display u iformity is general y me s red by tran latin the LMD p ral el

to the s re n an me s rin the display c aracteristic at dif ferent s re n location

However, f or con ex or con ave display , the display mou tin s al al ow the display to b

rotated a out its centre of c rvature whi e en urin that the imagin plane alway p s es

throu h the y-axis at the origin This is i u trated in Fig re 2 for the case of a con ex display

The same motion s al b u ed f or con ave display Fig re 2 i u trates how lateral location

the display u if ormity to b me s red at a con tant viewin direction Alternatively, the LMD

can b mou ted on a goniometer that rotates a out the display’s centre of c rvature

NOT Fig re 2 s ows h w a c n e dis la whic is c rv d with a c n ta t ra iu r c n b rotate a o t its

c ntre of c rv ture to alg difere t dis la lo atio s in th x-z pla e within th me s reme t field

Figure 2 – Top view e ample of how a conv x displa

c n be rotate within th me s reme t field

4.1.3 Displa mountin for viewing dire tion me s reme ts

Viewin direction me s rements on c rved display req ire the exact al g ment of the LMD

an the display.[1] The centre of the LMD me s rement field is u ual y alg ed p rp n ic lar

to the display s r ace Al g ment ac urac to within ±1° is recommen ed in order to minimize

1, P

con ition For the co rdinate s stem defined in Fig re 1, the LMD o tical axis would p s

throu h a c rved display’s centre of c rvature When me s rin the viewin de en en e of a

c rved display, the display mou t would ne d to rotate a out a p int on the display s race at

the centre of the me s rement field in the x-z plane (as s own in Fig re 3), or rotate in the y-z

plane The same motion would b req ired f or a f lat display Alternatively, the LMD can b

mou ted on a goniometer that rotates a out the same p int on the display s r ace at the

centre of the me s rement field ( he origin in the co rdinate s stem def i ed in Fig re 1)

NOT Th s f i ure s ow h w th dis la mo nt rotate a o t th s ra e of a c n e or flat dis la for viewin

dire tio me s reme ts

Figure 3 – To view e ample of displa mount that rotate in th x-z pla e

f or viewing dire tion me s reme ts

4.2 Light me s ring de ic

It is general y as umed that the LMD wi b a sp t photometer, colorimeter, or

sp ctroradiometer The optical c aracteristic of these in truments are i u trated in Fig re 4

The LMDs often have a selecta le me s rement-ield an le (sometimes caled the

me s rement a erture) that for a given me s rin distan e defines the me s rin field on the

display s race The me s rement-f ield an le s al b no gre ter than 2° The me s ring

distan e f om the LMD to the display s rf ace is nominal y 0,5 m This combination of

me s ring- ield an le an distan e u ual y satisfies the recommen ation that the

me s rement field contain at le st 5 0 pixels However, f or c rved display , if the

me s rement field b comes larger (or the radiu of c rvature b comes smaler), then the

LMD samples l g t f om the display s rf ace over a larger ran e of in l nation an les ∆θ

d The

ran e of in l nation an les sampled by the LMD is given by:

2arc sin

rc

θΔ

(1)

where c is the diameter of the me s rement field an r is the display radiu of c rvature

Fig re 5 provides an example of how the ran e of in l nation an les can vary for a given

me s rement field on display with a 3 mm an 4 mm radiu of c rvature In this example,

the ran e of me s rement field that contain at le st 5 0 pixels is identified by the s aded

region u der the c rves Fig re 5 also in lu es an example of the me s rement field that

can b o tained by a commercial sp ctroradiometer at a 0,5 m me s rement distan e as

identified by its me s rement-ield an les (LMD a erture)

d

> 5° for the 3 mm radiu of c rvature display However, if the LMD

me s rement distan e is red ced to 0,4 m for the 3 mm radiu of c rvature display, then ∆θ

d

would also f al b low 5°

Another method to red ce the ran e of display in l nation an les is to red ce the

me s rement- ield an le of the LMD But as the example in Fig re 5 s g ests, the smal er

me s rement- ield an les prod ce me s rement field that may not sample the

recommen ed > 5 0 display pixels This may b mitigated f or the 0,2° me s rement-ield

an le example in Fig re 5 by in re sin the me s rin distan e However, the combination of

smal er me s rement- ield an le an lon er me s rin distan e ten s to prod ce noisier

data, an could res lt in re rod cibi ty pro lems But if it can b demon trated that the

smal er me s rement-ield an les at s orter me s rin distan es give the same res lts as f or

LMD config ration that do contain at le st 5 0 pixels, then the smal er me s rement- ield

NOT 1 Fig re 5 s ows th relatio s ip b twe n th me s reme t field diameter a d th ra g of in ln tio s

a gle c pture within th me s reme t f i ld for a giv n dis la ra iu of c rv ture

NOT 2 Th s a owe are hig lg ts th re io wh re > 5 0 pix ls are s mple f or a giv n me s reme t f i ld

a gle (d s e ln )

Figure 5 – Ex mple of th relations ip betwe n me s reme t

f ield diameter a d incl nations a gle

4.3 Light sourc conf ig ration

Lig t sources wi b u ed to simulate the display p r orman e u der typical in o r or outdo r

ambient lg tin en ironments These en ironments general y contain a combination of

directed an u if orm hemispherical dif fu e l g t sources Subclau es 4.3.2 an 4.3.3 def i e

how these sources wi b config red when evaluatin the p r orman e of c rved display

u der simulated in o r an outdo r i umination con ition Flat display wi fol ow the same

general config ration, without the ne d to con ider the orientation of the display’s b n in

axis

4.3.2 Uniform hemispheric l dif f us i umination

Unif orm hemispherical dif fu e i umination is general y re l zed by u in an integratin

sphere For large display , an display with a large radiu of c rvature, the display may b

placed again t the sample p rt of a sampl n sphere an the me s rement are s ould b

within the u if orm i umination are of the display (se Fig re 6, config ration B) However, if

the display is to smal to fi the sample p rt of a sampl n sphere, or the c rvature of a

con ave display is smal er than the c rvature of the sampl n sphere, then the display s al

b placed in the centre of an integratin sphere (se Fig re 6, config ration A) In either

config ration, the lon axis of the c rved display (y-axis) s al b in the plane of in iden e of

the LMD an ti ted 8° to 10° f om the LMD o tical axis When u ing an integratin sphere, the

ref lection stan ard s ould b placed adjacent to the display an in the same plane as the

display me s rement are Best practices f or sphere desig an me s rements s al b

Directed source me s rements are p rtic larly sen itive to i umination are distortion an

u inten ed b am foc sin fom c rved display Therefore, display me s rements with

directed i umination s al u e the config ration i u trated in Fig re 7 The LMD an l g t

source o tical axis s al le in the y-z plane centred throu h the origin Alternatively, f or a

smal con ex display, a rin l g t centred a ove an /or b low the me s rement field can b

u ed to i uminate the me s rement f ield at a nominal 4 ° in l nation an le

(se Fig re 8).[1,2] The LMD me s rement are s al b centred an l e within the

i umination are The rin l g t i umination s own in Fig re 8 f ulfi s two con ition : the rin

l g t in l nation is 4 °, an the i uminan e (or sp ctral ir adian e) do s not c an e with

orientation alon the circ mferen e of the c l n er

IE C

y

z LMD

s urc

Figure 8 – Ex mple of conv x displa i uminate by a ring l g t sourc

5 Sta dard measuring conditions

5.1 Sta dard me s ring e vironme tal condition

Electro-o tical me s rements an vis al in p ction s al b car ied out u der the stan ard

en ironmental con ition as fol ows:

5.2 Sta d rd l ghtin conditions

5.2.1 Dark room conditions

The luminan e contribution f rom the b c grou d i umination reflected of the test display

s al b < 0,01 c /m

2

or les than 1/2 of the display’s blac state luminan e, whic ever is

lower If these con ition are not satisfied, then b c grou d s btraction is req ired an it

s al b noted in the test re ort In ad ition, if the sen itivity of the LMD is inadeq ate to

me s re at these low levels, then the lower l mit of the LMD s al b noted in the test re ort

Unles stated otherwise, the stan ard l g tin con ition s al b the dark ro m con ition

5.2.2 Sta dard ambie t i lumination spe tra

The fol owin i umination con ition are sp cified for the o tical me s rements of emis ive

an reflective display u der in o r or outdo r i umination con ition A combination of two

i umination ge metries is general y u ed to simulate ambient in o r i umination, or outdo r

dayl g t i umination u der a cle r s y.[4,5] Uniform hemispherical diff use i umination wi b

u ed to simulate the b c grou d lg tin in a ro m wit h the direct ed lg t source s c as a

luminaire in a room oc lu ed, or the hemispherical s yl g t in ident on the display, with the s n

oc lu ed A directed l g t source in a dark ro m wi simulate the eff ect of directed i umination

on a display by a luminaire in a ro m, or f om direct s nl g t

The fol owin i umination con ition , whic are con istent with OLED an electronic p p r

display (IEC 6 3 1-6-2 an IEC 6 6 9-3-1) s al b u ed to simulate in o r an outdo r

display viewin en ironments:

a) In o r ro m i umination con ition :

1) Uniform hemispherical diff use i umination

Use sp ctral y smo th bro db n l g t source to photometrical y a proximate CIE

Rin lg t

4 °

LMD

IE C

in CIE 15:2 0 Bet er ac urac can b o tained by p rf ormin sp ctral

me s rements For sp ctral me s rements, if it can b demon trated that the display

do s not ex ibit sig ificant photolumines en e (PL) (<1 % PL, se IEC 6 341

-6-2:2 15, An ex A) f or the selected ref eren e source sp ctra, then a sp ctral y smo th

bro db n source (s c as an a proximation to CIE Stan ard Il uminant A) may b

u ed to me s re the sp ctral reflectan e A me s rement of the sp ctral reflectan e

u in a bro d l g t source (s c as Il uminant A) ena les the in o r photo ic an

colour c aracteristic to b calc lated later for the desired referen e sp ctra (f or

example CIE Il uminant D6 ) The p r orman e c aracteristic s al b calc lated

u in 6 lx of u if orm hemispherical i umination (with sp c lar in lu ed) in ident on

the display s race f or a typical TV viewin ro m, an 3 0 lx for an in o r re din

en ironment.[6] The actual hemispherical diff use ref lectan e me s rement may

req ire hig er i umination levels for b ter me s rement ac urac The res lts are

then s aled to the req ired i umination levels

2) Directed i umination

The same source sp ctra s al b u ed as with hemispherical diff use i umination The

in o r ro m photo ic an colour display c aracteristic s al b calc lated u in

directed i umination of 2 0 lx in ident on the display s rf ace for an in o r readin

en ironment with the display in the vertical orientation The actual reflectan e factor

me s rement may req ire hig er i umination levels for b ter me s rement ac urac

The res lt s are t hen s aled t o t he req ired i umination lev els The directed source s al b

4 ° a ove the s r ace normal (θ

s

= 4 °)

Other i umination levels may b u ed in ad ition to those defined a ove for calc latin

the display c aracteristic u der in o r i umination con ition

b) Outdo r dayl g t i umination con ition :

1) Uniform hemispherical diff use i umination

Use sp ctral y smo th bro db n l g t source to photometrical y a proximate s yl g t

with the sp ctral distribution of CIE Il uminant D7 [7] Ad itional CIE dayl g t

i uminants (s c as D6 ) may also b u ed, de endin on the inten ed a pl cation

Beter ac urac can b o tained by p rf ormin sp ctral me s rements For sp ctral

me s rements, the sp ctral ref lectan e factor me s rements can b made u in a

sp ctral y smo th bro db n source (s c as an a proximation to CIE Stan ard

Il uminant A) Sk l g t photo ic an colour metric can b calc lated later for the CIE

D75 Il uminant sp ctra The s ylg t photo ic an colour c aracteristic s al b

calc lated u in 15 0 0 lx of hemispherical dif fu e i umination (with sp c lar in lu ed)

in ident on a display s rf ace in a vertical orientation.[7,8] The actual hemispherical

dif fu e reflectan e factor me s rement may b taken at lower i umination levels The

res lts are then s aled up to the req ired i umination levels

2) Directed i umination

The directed l g t source s al a proximate CIE dayl g t Il uminant D5 [6] Ad itional

CIE dayl g t i uminants (s c as D6 ) may also b u ed, de en in on the inten ed

a pl cation A sp ctral y smo th bro db n source (s c as an a proximation to CIE

Stan ard Il uminant A) may b u ed f or the reflectan e f actor me s rement The

s nl g t photo ic an colour c aracteristic can b calc lated later with the D5

Il uminant sp ctra The dayl g t photo ic an colour c aracteristic s al b calc lated

u in 6 0 0 lx for a directed source at an in l nation an le of θ

actual reflectan e f actor me s rement may b taken at lower i umination levels The

res lts are then s aled up to the req ired i umination levels The contrast ratio an

colour are calc lated f or the s aled-up i uminan e levels The directed source s al

have an an ular s bten e of a proximately 0,5°

For dayl g t photo ic an colour calc lation fom sp ctral ref lectan e factor me s rements,

the relative sp ctral distribution of CIE Iluminants A, D5 , D6 an D7 ta ulated in CIE

15:2 0 s al b u ed Ad itional CIE dayl g t i uminants s al b determined u in the

The UV region (< 3 0 nm) of the l g t source s al b c t of f by a UV bloc in fi ter When

hig l g t source i umination levels are u ed, an inf rared-bloc in fi ter is recommen ed to

minimize device he tin

5.2.3 Sta dard i umination geometrie

One or more of thre typ s of i umination ge metries s al b u ed for determinin the

p rorman e of the DUT: directional i umination, rin l g t i umination, an hemispherical

i umination The stan ard config ration f or implementin these i umination ge metries are

defined in IEC 6 6 9-3-1:2 14, 4.3.4 Ad itional i umination ge metries may also b u ed

The detai s of the i umination ge metry u ed f or a given me s rement s al b re orted

Further g idan e on the pro er implementation of these i umination ge metries is given in the

SID Inf ormation Display Me s rements Stan ard.[3]

5.2.4 Dif f us ref lecta c sta d rd

Dif fu e white reflectan e stan ard samples can b o tained with a diff use ref lectan e of 9 %

or more They are also avai a le in dif ferent s ades of grey A luminan e L

std

me s rement

f om s c reflectan e stan ard can b u ed to determine the i uminan e E on the stan ard

for defined detection ge metry an i umination sp ctra an config ration:

st d

st d

RL

Eπ

=

(2)

where R

std

is the cal brated luminou reflectan e factor for that me s rement config ration

When the i umination config ration is a u iform hemispherical i umination, then R

stdis

eq ivalent to luminou hemispherical reflectan e ρ

std The luminou reflectan e value

as ociated with the stan ard is only val d for the hemispherical i umination in whic it was

cal brated If it is u ed with a directed source at an an le, there is no re son to exp ct that

the luminou reflectan e value wi b the cor ect luminou reflectan e factor value for that

i umination config ration or sp ctrum

NOT Th term lumin u refle ta c or lumin u re e ta c fa tor wi simply b refere to a re e ta c or

re e ta c fa tor in th remain er of this d c me t

5.3 Sta dard setup conditions

5.3.1 Adjustme t of displa mod le

De en in on the inten ed a plcation, the display s al b me s red in a f lat state, or held

rigid with a smo th an con tant radiu of c rvature over its entire active are The display

s al b me s red at its f actory def ault set in s If other setin s are u ed, they s al b noted

in the test re ort These set in s s al b held con tant for al me s rements, u les stated

otherwise

If it can b demon trated that the o tical c aracteristic of the display in its f lat state are the

same as f or its c rved state, then the display may b me s red in the f lat state The b n in

state of the display u ed d rin the me s rements s al b re orted

5.3.2 Starting conditions of me s reme ts

Me s rements s al b started af ter the display mod les an me s rin in truments ac ieve

sta i ty Suf ficient warm-up time has to b al owed f or the display mod les to re c a

luminan e deviation level of les than ± % over the entire me s rement f or a given display

5.3.3 Conditions of me s ring e uipme t

Con ition of me s rin eq ipment are given IEC 6 6 9-3-1:2 14, 4.4.3 Any deviation f rom

these con ition s al b noted in the re ort

5.4 Sta dard loc tions of me s reme t field

Luminan e, sp ctral distribution an /or tristimulu me s rements may b taken at several

sp cified p sition on the DUT s race To this en , the active are of the display is divided

into 2 identical imaginary rectan les (se Fig re 9) Unles otherwise sp cified,

me s rements are car ied out in the centre of e c rectan le The rectan les are n mb red

startin f rom the centre, an progres in toward the ed es in a cloc -wise spiral fas ion

Care s al b taken that the me s rin f ield on the display do not overla Positionin of the

me s rin f ield at the pres rib d p sition in the horizontal (H) an vertical (V) direction s al

b to within 7 % of H an V, resp ctively The display or detector s al b tran lated in the

horizontal an vertical direction to p r orm me s rements at the desired display p sition ,

with al me s rements taken normal to the s re n An deviation f rom the a ove stan ard

e c re ta gle are 2 % of dis la h ig t a d width re p ctiv ly

Figure 9 – Sta dard me s reme t p sitions

6 Optical me suring methods in dark room conditions

6.1 Lumina c a d its uniformity

6.1.1 Ge eral

The purp se of this method is to determine the luminan e an the luminan e u iformity in the

display active are u der dark ro m con ition For reflective display , this method only

a pl es to display that have an integrated l g tin u it (ILU) an it is tested at the factory

stan ard setin s, u les sp cified otherwise Ad itional y, ILU levels may also b tested, but

IE C (5/10)H

(3/10)H

( /10)H ( /10)V

2

– a me n to tran late a flat display or LMD in the vertical an horizontal direction ;

– a display mou t that can rotate a c rved display a out its centre of c rvature

(se Fig re 2) or LMD that can b mou ted on a goniometer that rotates a out the

display’s centre of c rvature

6.1.3 Scre n c ntre lumina c me s ring method

The me s rin method s al b as f olows:

a) Mou t the display in its f lat or c rved state in a fixture ac ordin to the g idan e provided

in 4.1

b) Place the LMD at the recommen ed distan e f rom the display an al g the o tical axis to

b normal to the centre of the display active are (p sition P

0)

c) Set the display to a 4 % are win ow (se Fig re 10) at the desired colour Q at the

hig est luminan e level Alow the display to sta i ze

d) Me s re the display luminan e L

Q0for colour Q at p sition P

0

e) Re e t for other display colours as ne ded

f ) Re ort the s re n centre luminan e L

Q0

f or colour Q in the test rep rt

NOT A win ow of d sire c lo r Q is p sitio e in th c ntre of th s re n with a bla k b c gro n

Fig re 10 – Te t pat ern u e f or 4 % are window me s reme ts

6.1.4 Lumina c uniformity me s ring method

The me s rin method s al b as f ol ows:

a) Mou t the display in its flat or c rved state in a fixture that wi al ow the LMD to remain at

a fixed distan e f rom the me s rement f ield, and normal to the display s r ace at the

centre of the me s rement field

b) Place the LMD at the recommen ed distan e f om the display an al g the o tical axis to

c) Set the display to a ful s re n at the desired colour Q at the hig est luminan e level A

f ul white s re n is general y u ed Ad itional colour may also b me s red Al ow the

display to stabi ze

d) Me s re the display luminan e L

Q0for colour Q at p sition P

0

e) Move the display (se 4.1.2 for c rved display ) or LMD an take seq ential luminan e

me s rements at the five (p sition P

0, P

1, P

15, P

19

2) or nine (p sition P

0, P

9,

17, P

19, P

21

2) location def i ed in Fig re 9

6.1.5 Lumina c uniformity def inition a d e aluation

The p rcent luminan e non-u iformity of the display at colour Q is given by:

maQ,

minQ,maQ,

the me s red location

Al the luminan e values, the minimum an maximum luminan e values, an the luminan e

non-u iformity value s ould b re orted with a des ription of the me s rin con ition

6.2 Contra t ratio

The purp se of this method is to me s re the display contrast ratio in the centre of the active

are u der dark ro m con ition For reflective display , this method only a pl es to display

that have an integrated l g tin u it (ILU) an it is set to its maximum l g t level

6.2.2 Me s ring e uipme t

The a p ratu s al b as fol ows:

– a luminan e meter, colorimeter or spectroradiometer;

– a drivin power source;

b) Place the LMD at the recommen ed distan e f om the display an al g the o tical axis to

b normal to the centre of the display active are (p sition P

0)

c) Set the display to a 4 % are white win ow (se Fig re 10) at the hig est luminan e level

in the centre of the active are ; the remainin b c grou d is blac at the lowest luminan e

level Al ow the display to sta i ze

d) Me s re the display p ak white luminan e L

W0

at p sition P

0

e) Set the display to a f ul blac s re n at the lowest luminan e level Al ow the display to

6.2.4 Definition a d e aluation

0W

%4

LL

the centre of the s re n

The 4 % win ow dark ro m contrast ratio, in ad ition to the blac an p ak white luminan e

values, s al b re orted with a des ription of the me s rin con ition

6.3 Chromaticity, colour unif ormity, a d colour gamut are

The purp se of this method is to me s re the display c romaticity for a desired colour Q, the

colour u iformity, an colour gamut are u der dark ro m con ition It is also p s ible to

expres the colour gamut are u der ambient con ition u in the ambient c romaticity

co rdinates o tained in 7.3 For reflective display , this method only a pl es to display that

have an integrated l g tin u it (ILU) an it is tested at the factory stan ard set in s, u les

sp cified otherwise Ad itional y, ILU levels may also b tested, but the l g t level s ould b

re orted with the test res lts

6.3.2 Me s ring e uipme t

The a p ratu s al b as fol ows:

– a colorimeter or sp ctroradiometer;

– a drivin p wer source;

– drivin sig al eq ipment

The display s al b mou ted an al g ed ac ordin to the g idan e provided in 4.1

6.3.3 Scre n c ntre c romaticity me s rin method

The me s rin method s al b as fol ows:

a) Mou t the display in its flat or c rved state in a f i ture ac ordin to the g idan e provided

in 4.1

b) Place the LMD at the recommen ed distan e f om the display an al g the o tical axis to

b normal to the centre of the display active are (p sition P

0)

c) Set the display to a 4 % are win ow (se Fig re 10) at the desired colour Q at the

hig est luminan e level Alow the display to sta i ze

d) Me s re the CIE 19 1 c romaticity co rdinates (x , y ) for colour Q at p sition P

0

e) The folowin tran formation s al b u ed to calc late the CIE 19 6 UCS c romaticity

co rdinates (u′

Q, v′

Q) f or colour Q:

QQQ

Q

QQQ

Q

12239

',

12234

'

yxy

v

yxx

f ) Re e t for other display colours as ne ded

g) Re ort the CIE 19 1 c romaticity co rdinates, the display setin s, an the me s rement

6.3.4 Scre n c ntre colour gamut a d colour gamut are me s rin method

The me s rin method s al b as f ol ows:

a) Use the me s rin method in 6.3.3 to determine the CIE 19 1 an CIE 19 6 UCS

c romaticity co rdinates f or white, red, gre n, and blue colours at the digital input signal

levels sp cified in Ta le 1

b) The colour gamut is general y re resented by the trian le in the CIE 19 1 c romaticity

diagram formed by the red (x

R, y

R), gre n (x

G, y

G), an blue (x , y ) colours as corner

p ints An example of me s rin res lts is s own in Fig re 1

c) The colour gamut are is def i ed as the p rcent colour sp ce are en losed by the colour

gamut relative to the entire sp ctrum loc s in the CIE 19 6 UCS c romaticity diagram

(se Fig re 1 ) For thre -primary display , this is calc lated as:

A = 2 6,1 x |(u′

R-u′

B) v′

G-v′

B)-(u′

G-u′

B) v′

R-v′

B

where the s bs ripts R, G an B refer to the red, gre n, an blue primaries, resp ctively

The colour gamut are for the sRGB primaries (IEC 619 6-2-1) havin the CIE 19 1 (x, y)

c romaticities red (0,6 , 0,3 ), gre n (0,3 , 0,6 ), an blue (0,15, 0,0 ) would b 3 %

Table 1 – Input sign ls for CIELAB, CIE 19 1 a d CIE 19 6 UCS

a) CIE 19 1 chromaticity diagram

b) CIE 19 6 U S chromaticity diagram

Fig re 1 – Ex mple of the colour gamut a repre e te in two common

c romaticity diagrams

d) Re ort the CIE 19 1 an CIE 19 6 UCS c romaticity co rdinates for white, RGB, the CIE

IE C u'

6.3.5 Colour u if ormity me s rin method

The me s rin method s al b as f ol ows:

a) Mou t the display in its flat or c rved state in a fixture that wi al ow the LMD to remain at

a f i ed distan e f rom the me s rement field, an normal to the display s r ace at the

centre of the me s rement field

b) Place the LMD at the recommen ed distan e f om the display an al g the o tical axis to

b normal to the centre of the display active are (p sition P

0)

c) Set the display to a ful s re n at the desired colour Q at the hig est luminan e level A

ful white s re n is general y u ed Ad itional colour may also b me s red Al ow the

display to sta i ze

d) Me s re the display CIE 19 1 c romaticity co rdinates (x

Q, y

Q) for colour Q at p sition

1, P

15, P

19

2) or nine (p sition P

0, P

9,

17, P

19, P

21

2) location def i ed in Fig re 9

f) Use Formula (5) to o tain the CIE 19 6 UCS c romaticity co rdinates (u′ v′) fom the CIE

19 1 c romaticity co rdinates (x, y)

g) Use the CIE 19 6 UCS c romaticity co rdinates (u′ v′) at e c location P

i2

'

j'

i'

vvuuv

∆

(7)

f or i, j = 0 to 4 or i, j = 0 to 8, an i ≠ j Colour non-u iformity is defined as the largest

sampled c romaticity diff eren e (∆u’v’

ma

b twe n an two p ints

h) Determine the largest c romaticity diff eren e An example of a nine-p int me s rement is

given in Ta le 2 The largest colour dif feren e can b nar owed down by plotin the nine

(u’, v’ co rdinates rather than calc latin al (u’, v’ p irs

i) Re ort the largest CIE 19 6 UCS c romaticity dif feren e to no smaler u certainty than

v′

∆u’v’

P

0P

1P

2P

3P

4P

5P

6P

7P

6.4 Pe k white f ield cor elate colour temperature

The purp se of this method is to me s re the display p ak white cor elated colour

temp rature u der dark ro m con ition For ref lective display , this method only a pl es to

display that have an integrated lghtin u it (ILU) an it is set to its maximum lg t level

The me s rin method s al b as fol ows:

a) Mou t the display in its flat or c rved state in a f i ture ac ordin to the g idan e provided

in 4.1

b) Place the LMD at the recommen ed distan e fom the display an al g the o tical axis to

b normal to the centre of the display active are (p sition P

0)

c) Set the display to a 4 % are white win ow (se Fig re 10) at the hig est luminan e level

Al ow the display to sta i ze

d) Me s re the p ak white CIE 19 1 c romaticity co rdinates (x

W, y

W) at p sition P

0

e) Me s re the CCT directly with the LMD If the me s rement in trument do s not provide

the CCT directly, the CCT can b a proximated by McCamy’s f ormula:

5517

6 613601

23

CCT

++

18 8,0/

The CCT is general y only val d for white colours, not in ivid al primaries

f) Re ort the CCT, the display set in s, an the me s rement con g ration

6.5 Viewing dire tion depe de c

The purp se of this method is to me s re the photometric an colorimetric prop rties of the

display over a ran e of viewin direction u der dark ro m con ition For reflective display ,

this method only a pl es to display that have an integrated l g tin u it (ILU) an it is set to

its maximum l g t level

6.5.2 Me s ring e uipme t

The a p ratu s al b as f ol ows:

– a colorimeter or sp ctroradiometer;

– a drivin p wer source;