Iec 62341 6 4 2017

I E C 62 41 -6-4 ® Edition 201 7-05 I N TE RN ATI ON AL S TAN D ARD colour i n sid e Org an i c l i g h t em i tti n g d i od e (OLE D ) d i s pl a ys – IEC 62341 -6-4:201 7-05(en) P art 6-4: M e as u ri n g m eth od s of tran s paren t prope rti es T H I S P U B L I C AT I O N I S C O P YRI G H T P RO T E C T E D C o p yri g h t © I E C , G e n e v a , S wi tz e rl a n d All rights reserved Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or IEC's member National Committee in the country of the requester If you have any questions about I EC copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or your local I EC member National Committee for further information IEC Central Office 3, rue de Varembé CH-1 21 Geneva 20 Switzerland Tel.: +41 22 91 02 1 Fax: +41 22 91 03 00 info@iec.ch www.iec.ch Ab ou t th e I E C The I nternational Electrotechnical Commission (I EC) is the leading global organization that prepares and publishes I nternational Standards for all electrical, electronic and related technologies Ab o u t I E C p u b l i ca ti o n s The technical content of IEC publications is kept under constant review by the IEC Please make sure that you have the latest edition, a corrigenda or an amendment might have been published I E C Catal og u e - webstore i ec ch /catal og u e The stand-alone application for consulting the entire bibliographical information on IEC International Standards, Technical Specifications, Technical Reports and other documents Available for PC, Mac OS, Android Tablets and iPad I E C pu bl i cati on s s earch - www i ec ch /search pu b The advanced search enables to find IEC publications by a variety of criteria (reference number, text, technical committee,…) It also gives information on projects, replaced and withdrawn publications E l ectroped i a - www el ectroped i a org The world's leading online dictionary of electronic and electrical terms containing 20 000 terms and definitions in English and French, with equivalent terms in additional languages Also known as the International Electrotechnical Vocabulary (IEV) online I E C G l os sary - s td i ec ch /g l oss ary 65 000 electrotechnical terminology entries in English and French extracted from the Terms and Definitions clause of IEC publications issued since 2002 Some entries have been collected from earlier publications of IEC TC 37, 77, 86 and CISPR I E C J u st Pu bl i s h ed - webstore i ec ch /j u stpu bl i sh ed Stay up to date on all new IEC publications Just Published details all new publications released Available online and also once a month by email I E C C u stom er S ervi ce C en tre - webstore i ec ch /csc If you wish to give us your feedback on this publication or need further assistance, please contact the Customer Service Centre: csc@iec.ch I E C 62 41 -6-4 ® Edition 201 7-05 I N TE RN ATI ON AL S TAN D ARD colour i n sid e Org an i c l i g h t em i tti n g d i od e (O LE D ) d i s pl a ys – P art 6-4: M eas u ri n g m eth od s of tran s paren t properti es INTERNATIONAL ELECTROTECHNICAL COMMISSION ICS 31 260 ISBN 978-2-8322-4297-1 Warn i n g ! M ake s u re th a t you ob tai n ed th i s p u b l i cati on from an au th ori zed d i stri b u tor ® Registered trademark of the International Electrotechnical Commission –2– I EC 62341 -6-4: 201  I EC 201 CONTENTS FOREWORD Scope Norm ative references Terms and definitions Measuring conditions Standard m easuring environmental conditions Standard lighting conditions Darkroom conditions 2 Ambient illumination conditions Ambient illumination spectra Standard setup conditions Starting conditions of m easurem ents Conditions of measuring equipm ent Measuring methods of transparent properties Measuring methods of transm ission perform ance Hemispherical transmittance factor with specular included Transm itted haze under hem ispherical illum ination Directional transmittance factor Measurement method of purity Colour variation caused by a transparent displ ay Measuring methods of on-screen performance in a darkroom 20 Lum inance and its uniform ity 20 2 Chrom aticity and colour non-uniform ity 23 Darkroom contrast ratio 24 Grey scale and gam ma characteristics 25 5 Colour gam ut 27 Directional optical characteristics 29 Measuring methods of reflection properties 30 Hemispherical reflectance factor with specular included 30 Purpose 30 Measuring conditions 30 Measuring m ethod 30 Directional reflectance factor 31 Purpose 31 2 Measuring conditions 31 Measuring m ethod 31 Optical on-screen performance under am bient illum ination 31 Ambient contrast ratio 31 Purpose 31 Measuring conditions 32 Measuring m ethod 32 Display am bient colour measurem ent 33 Purpose 33 2 Measuring conditions 33 Measuring m ethod 34 I EC 62341 -6-4: 201  I EC 201 –3– Annex A (normative) Alternative method for measuring the hem ispherical transm ittance factor of a transparent OLED display 36 A Purpose 36 A Measuring conditions 36 A Measuring the transmittance 36 Bibliograph y 39 Figure – Layout diagram of m easurem ent setup Figure – Side view of measuring concept for the hem ispherical transmittance factor measurement with specular included or excluded Figure – Schematic arrangem ent of haze m easurement Figure – Side view of measuring concept for the hemispherical transm ittance factor measurement with specular included or excluded Figure – Measuring configuration for purity m easurem ent Figure – Test patterns for purity measurem ent Figure – Test pattern for % window lum inance 21 Figure – Exam ple of luminance loading m easurement 22 Figure – Measurement locations 23 Figure – Measuring patterns for gamm a m easurem ent 26 Figure A – Measurem ent geom etry using a sam pling sphere 37 Table Table Table Table Table Table Table Table Table Table Table – Standard am bient conditions –Measuring conditions of the ports – Measured example for purity – Working exam ple for colour variation index 20 – Worked exam ple for luminance loading 22 – Exam ple of luminance non-uniformity 23 – Exam ple of colour uniformity m easurem ent 24 – Exam ple of gamma measurem ent 26 – Reference areas for the colour reproduction range 28 – Example of measurem ent for the colour gamut variation ratio 28 1 – Example of measurem ent for the directional electro-optical characteristic 30 –4– I EC 62341 -6-4: 201  I EC 201 INTERNATI ONAL ELECTROTECHNI CAL COMMISSI ON O RG AN I C L I G H T E M I T T I N G D I O D E ( O L E D ) D I S P L AYS – P a rt -4 : M e a s u ri n g m e th o d s o f tra n s p a re n t p ro p e rti e s FOREWORD ) The I nternati on al Electrotechni cal Comm ission (I EC) is a worl d wid e organization for stan dardization com prisin g all n ation al el ectrotechnical comm ittees (I EC National Comm ittees) The object of I EC is to prom ote internati onal co-operation on all questions concerni ng stand ardi zati on in the el ectrical an d electronic fields To this end and in additi on to other acti vities, I EC publish es I nternational Stan dards, Techn ical Specifications, Technical Reports, Publicl y Avail abl e Specificati ons (PAS) an d Gu ides (h ereafter referred to as “I EC Publication(s)”) Thei r preparation is entrusted to technical comm ittees; any I EC National Comm ittee interested in the subj ect dealt with m ay partici pate in this preparatory work I nternational, governm ental an d n on governm ental organ izations l iaising with th e I EC also participate i n this preparation I EC collaborates closel y with the I ntern ational Organi zation for Stand ardization (I SO) in accordance with ditions determ ined by agreem ent between th e two organi zati ons 2) The form al decisions or ag reem ents of I EC on tech nical m atters express, as n early as possible, an i nternati onal consensus of opi nion on the rel evant subjects since each technical com m ittee has representati on from all interested I EC N ational Com m ittees 3) I EC Publications have the form of recomm endations for intern ational use an d are accepted by I EC National Com m ittees in that sense While all reasonable efforts are m ade to ensure that the tech nical content of I EC Publications is accu rate, I EC cann ot be h eld responsi ble for th e way in which th ey are used or for an y m isinterpretation by an y en d u ser 4) I n order to prom ote intern ational u niform ity, I EC National Com m ittees und ertake to apply I EC Publications transparentl y to the m axim um extent possible i n their national an d regi on al publicati ons Any d ivergence between an y I EC Publication and the correspondi ng national or regi on al publicati on sh all be clearl y in dicated in the latter 5) I EC itself d oes n ot provi de an y attestation of conform ity I n dependent certificati on bodies provi de conform ity assessm ent services and, in som e areas, access to I EC m arks of conform ity I EC is not responsi ble for an y services carri ed out by ind ependent certification bodi es 6) All users shou ld ensure that th ey h ave the l atest editi on of thi s publicati on 7) No liability shall attach to I EC or its directors, em ployees, servants or ag ents inclu din g in divi du al experts an d m em bers of its tech nical com m ittees and I EC Nati onal Com m ittees for any person al i nju ry, property d am age or other dam age of any n ature whatsoever, whether di rect or indirect, or for costs (includ i ng leg al fees) and expenses arisi ng out of the publ ication, use of, or relian ce upon, this I EC Publicati on or any other I EC Publications 8) Attention is drawn to th e N orm ative references cited in th is publ ication Use of the referenced publ ications is indispensable for the correct applicati on of this publication 9) Attention is drawn to the possibility that som e of the elem ents of this I EC Publication m ay be the su bject of patent rig hts I EC shall not be held responsibl e for identifyi ng any or all such patent ri ghts I nternational Standard I EC 62341 -6-4 has been prepared by I EC technical com mittee 1 0: Electronic display devices The text of this I nternational Standard is based on the following documents: FDI S Report on votin g 1 0/843/FDI S 1 0/866/RVD Full information on the voting for the approval of this I nternational Standard can be found in the report on voting indicated in the above table This docum ent has been drafted in accordance with the I SO/I EC Directives, Part A list of all parts in the I EC 62341 series, published under the general title emitting diode (OLED) displays , can be found on the I EC website Organic light I EC 62341 -6-4: 201  I EC 201 –5– The comm ittee has decided that the contents of this document will rem ain unchanged until the stability date indicated on the I EC website under "http://webstore iec.ch" in the data related to the specific docum ent At this date, the docum ent will be • • • • reconfirm ed, withdrawn, replaced by a revised edition, or amended A bilingual version of this publication may be issued at a later date I M P O R T AN T – T h e ' c o l o u r i n s i d e ' th at it tai n s u n d e rs t a n d i n g c o l o u r p ri n t e r of c o l o u rs i ts wh i c h c o n te n ts l og o a re U s e rs on th e co ve r p ag e o f th i s c o n s i d e re d s h ou l d to t h e re fo re be p u b l i c ati o n u s e fu l p ri n t th i s fo r i n d i c a te s th e d o cu m en t c o rre c t u sin g a –6– I EC 62341 -6-4: 201  I EC 201 O RG AN I C L I G H T E M I T T I N G D I O D E ( O L E D ) D I S P L AYS – P a rt -4 : M e a s u ri n g m e th o d s o f tra n s p a re n t p ro p e rti e s S cop e This part of I EC 62341 specifies the standard measurement conditions and measuring methods for determ ining the optical performance of transparent properti es of organic light emitting diode (OLED) display panels and modules This docum ent includes the display perform ance under darkroom conditions, and front and back illumination N o rm a t i ve re fe re n c e s The following documents are referred to in the text in such a way that som e or all of their content constitutes requirements of this docum ent For dated references, onl y the edition cited applies For undated references, the latest edition of the referenced docum ent (including an y am endm ents) applies I EC 62341 -1 -2, letter symbols Organic light emitting diode (OLED) displays – Part 1-2: Terminology and Organic light emitting diode (OLED) displays – Part 6-1: Measuring methods of optical and electro-optical parameters I EC 62341 -6-1 , Organic light emitting diode (OLED) displays – Part 6-2: Measuring methods of visual quality and ambient performance I EC 62341 -6-2, Ergonomics of human-system interaction – Part 307: Analysis and compliance test methods for electronic visual displays I SO 9241 -307, I SO 1 664-2, Colorimetry – Part 2: CIE standard illuminants CI E 5-2004, Colorimetry T e rm s a n d d e fi n i t i o n s For the purposes of this document, the term s and definitions given in I EC 62341 -1 -2 and the following appl y I SO and I EC maintain term inological databases for use in standardization at the following addresses: • I EC Electropedia: available at http: //www electropedia.org/ • I SO Online browsing platform : available at http://www iso.org/obp t n s m i t t a n c e fa c t o r ratio of the radiant or luminous flux transm itted in the direction delimited by the given solid angle cone to that transmitted in the sam e direction and solid angle cone by a perfect transm itting diffuser identicall y irradiated or illuminated Note to entry: When the term transm ittance factor is used in this docum ent, it refers to the photopicall yweig hted lum inous flu x I EC 62341 -6-4: 201  I EC 201 –7– spectral tran sm i ttan ce factor ratio of the spectral radiant flux transmitted in the direction delimited by the given solid angle cone to that transmitted in the same direction by a perfect transm itting diffuser identically irradiated 3 tran sm i tted h aze percentage of transm itted luminance, passing through a specimen, which deviates from the incident light by no m ore than 0, 044 rad (2, 5°) by forward scattering pu ri ty ratio of the luminance measured in the 0, 2° region to the lum inance of the total transmitted light Note to entry: Th e purity is defined as how clearl y the see-th rough im age coul d be seen The purity is deri ved from the m easurem ent of distorted li ght d ue to diffraction or refraction on -screen perform an ce optical perform ance that can be measured on the transparent screen when viewing an image on the screen M easuri ng di ti ons Stan d ard m easu ri n g en vi ron m en tal d i ti on s Measurements shall be carried out under the standard environmental conditions: Tem perature: Relative hum idity: Atm ospheric pressure: 25 ºC ± ºC 25 % RH to 85 % RH 86 kPa to 06 kPa When different environmental conditions are used, they shall be noted in the m easurement report 4 Stan d ard l i g h ti n g d i ti on s Darkroom d i ti on s The luminance contribution from the background illum ination reflected off and/or transmitted through the test display shall be less than 0, 01 cd/m or /20 of the display’s black state luminance, whichever is lower I f these conditions are not satisfied, then background subtraction is required and it shall be noted in the report I n addition, if the sensitivity of the light m easuring device (LMD) is inadequate to measure at these low levels, then the lower limit of the LMD shall be noted in the measurem ent report 2 Am bi en t i l l u m i n ati on d i ti on s Am bient lighting conditions can m ake a large im pact on the perform ance of a transparent display For observers who will watch a transparent display, various ambient conditions shall be suggested based on previous research Table shows the standard indoor and daylight ambient illumination conditions –8– I EC 62341 -6-4: 201  I EC 201 Uniform hemispherical diffuse illum ination will be used to simulate the background lighting in a room or the hemispherical skylight incident on the display, with sun occluded The detail information to sim ulate those am bient conditions is described in I EC 62341 -6-2 and I DMS [1 ] Tabl e Desi g n – S tan d a rd am bi en t d i ti on s Re c o m m e n d e d s c re e n I n d oor an d d a yl i g h t i l l u m i n a t i o n e n v i ro n m e n t i l l u m i n a ti o n i l l u m i n an ce Up to 200 l x (m ostly) General buildi ng areas (I SO 9241 -307) g e o m e try 60 % hem ispherical, 40 % directional at 45° Up to 300 l x (m ostly) General m achine work, roug h assem bly work, (general ) m useum (I SO 9241 -307), office en vironm ent [8] 60 % hem ispherical, Up to 500 l x Medium assem bly and decorati ve work, sim ple inspection, counters, librari es, (m ostly) ed ucation al areas, control room s (I SO 9241 -307) 60 % hem ispherical, Fine work, techn ical d rawing (I SO 9241 -307) 60 % hem ispherical, Up to 750 l x Up to 000 l x Up to 500 l x > 500 l x 80 000 l x 40 % directional at 45° 40 % directional at 45° 40 % directional at 45° Precision work, q uality control , inspection, m edical exam inati on and treatm ent (I SO 9241 -307) 60 % hem ispherical, High precision work (I SO 9241 -307) 60 % hem ispherical, 40 % directional at 45° 40 % directional at 45° Special workpl aces in th e m edical area (I SO 9241 -307) 60 % hem ispherical, 40 % directional at 45° The d ayli ght contrast ratio and colou r shall be calculated using a com binati on of hem ispherical diffuse il lum ination (with specular inclu ded ) and di rectional ill um ination i ncident on a display surface in a vertical ori entation [8][9] Am b i e n t i l l u m i n a t i o n 000 l x hem ispherical, 65 000 l x direction al at 45° s p e c t The am bient performance of the display can be significantly im pacted by the spectral distribution of the illum ination source Unless it is specified otherwise, the source illum ination shall closely approxim ate CI E I lluminant D65 (see CI E 5) The source illum ination used for measuring the display reflection and transmission properties shall have a spectrall y smooth and broadband em ission Spectral reflection and transm ission m easurem ents can then be used to predict the am bient display performance for an y desired i llumination spectra When evaluating the display’s ambient indoor performance, it is recomm ended to use the sam e spectral distribution for the hemispherical and directional source illumination Light source spectra approximating CI E I llum inant A, I lluminan t D50, and I lluminant D65 are recomm ended for indoor applications For sim ulating outdoor applications, I llum inant D50 is recomm ended for the directional illumination, and I lluminant D75 is recomm ended for hem ispherical illumination 4 S t a n d a rd s e tu p c o n d i ti o n s S t a rt i n g c o n d i t i o n s o f m e a s u re m e n t s Standard setup conditions are given below Measurem ents shall be started after the transparent OLED display and m easuring instruments achieve stability Sufficient warm -up time has to be allowed for the transparent OLED display panels and m odules to reach a _ Num bers in sq uare brackets refer to the Bi bliography – 28 – I EC 62341 -6-4: 201  I EC 201 Table – Reference areas for the colour reproduction range N TSC BT 709 [5] (sRGB) Adobe RGB 5.2.5.4 A ref ( u’v’ ) x y u’ v’ R 0, 67 0, 33 0, 476 0, 528 G 0, 21 0, 71 0, 075 0, 575 B 0, 0, 08 0, 52 0, 95 R 0, 64 0, 33 0, 450 0, 522 G 0, 30 0, 60 0, 25 0, 562 B 0, 0, 06 0, 75 0, 57 R 0, 64 0, 34 0, 441 0, 527 G 0, 21 0, 71 0, 075 0, 575 B 0, 0, 06 0, 75 0, 57 38 % 33 % 38 % Colour gamut variation ratio measurement For this m easurement, the following method shall be applied ) The measuring m ethod is the sam e as in 5 3, but with each prim ary at a defined colour level j (where j can be 255, 91 , etc.) 2) The full-screen patterns of primary colour level are measured and the colour gam ut area and colour reproduction range are calculated repeatedl y for each colour level j 3) The colour gamut variation ratio GR is calculated using Form ula (1 6) GR j = Sj × 00 Smax (1 6) where is the colour reproduction range of the colour level j ; is the colour reproduction range of the m axim um colour level 4) Report the results of measurements as shown in the exam ples in Table Sj Sm ax Table – Example of measurement for the colour gamut variation ratio R G B Colour level u’ v’ u’ v’ u’ v’ 255 0, 454 0, 524 0, 27 0, 559 0, 79 91 0, 452 0, 523 0, 26 0, 558 27 0, 447 0, 520 0, 27 63 0, 41 0, 500 0, 29 S GR 0, 45 03, % 00 % 0, 79 0, 45 02, % 99 % 0, 557 0, 79 0, 48 99, % 97 % 0, 549 0, 80 0, 66 83, % 81 % S is calculated with the referen ce area of BT 709 (sRGB), A ref = 33 % _ Adobe® RGB (1 998) is the trade nam e of a product suppli ed by Adobe System s I ncorporated This inform ation is given for the ven ience of users of this d ocum ent and does not constitute an end orsem ent by I EC of th e product nam ed Equ ivalent products m ay be used if th ey can be shown to l ead to the sam e results I EC 62341 -6-4: 201 6.1  I EC 201 – 29 – Di rection al opti cal ch aracteri sti cs Pu rpose The purpose of this method is to measure the directional optical characteristics of the transparent OLED display All the m easurement m ethods in are taken from IEC 62341 -6-3 [6] 6.2 M easu ri n g dition s For this m easurement, the following conditions shall be applied: a) Apparatus: ) spectroradiom eter or equivalent light m easuring devices that can measure the luminance and chrom aticity of the em itted light; 2) driving power source; 3) driving signal equipm ent b) Standard measuring conditions: ) darkroom conditions; 2) standard setup conditions 6.3 M easu ri n g meth od s For this m easurement, the following methods shall be applied ) The measuring m ethods are sam e as in to 5 Each item is m easured at specific viewing angles rendering a red, green, and blue full screen in sequence 2) Report the measurement results with the perpendicular m easurem ent The directional distortion ratio, D θ , of the electro-optical value (for lum inance and gam ma) is calculated using Form ula (1 7): Dθ ( Mθ ) = Mθ −M M0  × 00 (1 7)  where θ is the viewing angle and Mθ is the electro-optical value When evaluating the colour directional distortion, the CI E 976 chrom aticity coordinates are used with Form ula (1 8) Dθ ( ∆u ' v' ) = (u ' θ −u ' )  + (v' θ −v'  ) 3) Report the results of m easurements as shown in the examples in Table 1 (1 8) – 30 – I EC 62341 -6-4: 201  I EC 201 Table 1 – Example of measurement for the directional electro-optical characteristic Viewing angle 0° 30 ° 45 ° 60 ° 80 ° Luminance ( L W ) 402 377 348 301 83 D θ (L) - 6% 13 % 25 % 54 % Gamma 2, 21 2, 20 2, 21 2, 21 2, 23 D θ (Gamma) - 0, % 0, % 0, % ,1 % Chromati city △ D θ ( u’v’) u’ v’ u’ v’ u’ v’ u’ v’ u’ v’ R 0, 455 0, 525 0, 457 0, 525 0, 459 0, 525 0, 460 0, 525 0, 460 0, 524 G 0, 27 0, 560 0, 24 0, 561 0, 23 0, 562 0, 21 0, 564 0, 1 0, 564 B 0, 79 0, 46 0, 78 0, 49 0, 77 0, 50 0, 77 0, 50 0, 79 0, 47 R - 0, 002 0, 004 0, 006 0, 005 G - 0, 003 0, 005 0, 007 0, 009 B - 0, 004 0, 005 0, 005 0, 001 Measuring methods of reflection properties 6.1 6.1 Hemispherical reflectance factor with specular included Pu rpose The purpose of this method is to m easure the fraction of reflected light, including the specular com ponent, from the front of a transparent OLED display when illuminated with hemispherical illum ination 6.1 M easuring conditions For this m easurement, the following conditions shall be applied: a) Apparatus: ) light m easuring device that can measure lum inance or spectral radiance; 2) driving power source; 3) driving signal equipment; 4) integrating sphere or sampling sphere with a stabilized light source b) Specific guidance for the sphere design and measurem ent best practice is given in I EC 62341 -6-2 c) Standard m easuring environm ental conditions: ) darkroom conditions; 2) standard set-up conditions 6.1 M easuring method For this m easurement, the following methods shall be applied NOTE This m ethod assum es that the scatter properties of the transparent OLED display are i nd epend ent of th e illum ination level on the display NOTE I t is noted that it is not uncomm on for the OLED reflection properti es to be largel y invari ant with the ren dered colou r NOTE I f that can be dem on strated, th en the refl ection properti es can be m easu red with the displ ay turned off I EC 62341 -6-4: 201  I EC 201 – 31 – ) The measuring method in I EC 62341 -6-2 shall be used to m easure the lum inous hem ispherical reflectance ρ or spectral hem ispherical reflectance ρ ( λ ), with specular included, for the front of the transparent OLED display with the display rendering the desired colour Q 2) All other necessary colours will be measured in the sam e fashion in turn Di recti on al refl ectan ce factor Pu rpose The purpose of this method is to m easure the fraction of reflected light, relative to an ideal Lambertian diffuser, from the front of a transparent OLED display wh en illuminated by a directional source at a 45° inclination angle 2 M easu ri n g dition s For this measurem ent, the following conditions shall be applied a) Apparatus: ) light measuring device that can m easure luminance or spectral radiance; 2) driving power source; 3) driving signal equipment; 4) ring light with a stabilized light source b) Specific guidance for the sphere design and measurement best practice is given in I EC 62341 -6-2 c) Standard measuring environm ental conditions: ) darkroom conditions; 2) standard set-up conditions M easu ri n g meth od For this measurem ent, the following method shall be applied NOTE This m ethod assum es that the scatter properties of the transparent OLED display are i nd epend ent of th e illum ination level on the display NOTE I t is noted that it is not uncomm on for the OLED reflection properti es to be largel y invari ant with the ren dered colou r NOTE I f that can be dem on strated, th en the refl ection properti es can be m easu red with the displ ay turned off ) The ring light m easuring method in I EC 62341 -6-2 shall be used to m easure the luminous directional reflectance factor R or spectral directional reflectance factor R ( λ ) for the front of the transparent OLED display with the display rendering the desired colour Q 2) All other necessary colours will be m easured in the same fashion in turn Opti cal on-screen performance u nder ambi ent i l l umi nati on 7 Ambi en t trast ratio Pu rpose The purpose of this m ethod is to determine the am bient contrast ratio of a transparent OLED display module under defined indoor or daylight illum ination conditions NOTE I f the OLED exhibits significant PL, th en th e on-screen am bient contrast ratio calculation is onl y vali d for the sam e illum ination spectra and g eom etry used to m easure the transm ission and reflection coefficients – 32 – I EC 62341 -6-4: 201  I EC 201 M easu ri n g d i ti on s For this m easurement, the following conditions shall be applied a) Apparatus: ) light m easuring device that can measure lum inance or spectral radiance; 2) driving power source; 3) driving signal equipment; 4) directional light source; 5) integrating sphere or sampling sphere with a stabilized light source b) I llum inance condition: ) the standard am bient illum ination conditions for an indoor room or clear sky daylight shall be used, as specified in Clause 4; 2) additional illumination conditions may also be used, depending on the application c) Standard measuring environm ental conditions: ) darkroom conditions; 2) standard setup conditions M easu ri n g m eth od For this m easurement, the following method shall be applied NOTE Th e am bient contrast ratio is d eterm ined from the transm ission an d reflection m easurem ents of the display u nder h em ispherical diffuse and directed source ill um ination cond itions NOTE These m easu rin g m ethods are described in 3 NOTE The resu lting transm ission and refl ection coefficients will be used to calcul ate the com bined (em itted, transm itted, and refl ected ) lum inance of a d isplay with a black screen and white screen at the req uired ill um inance levels NOTE Th e am bient contrast ratio is the ratio of the com bined white screen l um inance to th e com bined bl ack screen l um inance ) Measure the black lum inance L m in at the centre and perpendicular to the display at a % grey level for a full black screen 2) Set the test input signal to the display to generate a 00 % grey level over the full screen or % window (see 2.3.3 2) located in the centre of the display, depending on the intended application 3) Measure the white luminance L m ax at the centre and perpendicular to the white display pattern under dark room conditions 4) Calculate the am bient contrast ratio as specified for the intended application using the following formula: ACR j = Lmax + Lmax,amb L + Lmin,amb (1 9) and LQ,amb = ρ Q,di/0 × EF,hemi + ρ Q,45/0 × EF,hemi × cos θ F,s + TQ,di/0 × EB,hemi + TQ,45/0 × EB,hemi × cos θ B,s (20) π π π π where Q represents the m easured values with the display in the white state (m axim um ) or black state (m in im um ); I EC 62341 -6-4: 201  I EC 201 – 33 – ρ Q, di/0 is the front reflectance for uniform hemispherical illum ination with specular included; is the front illuminance for uniform hemispherical illum ination of the spectral EF, hem i source to be evaluated; is the front spectral reflectance factor for a directional light source at an R Q, 45/0 inclination angle θF, s = 45 ° ; EF, dircos θ F, s is the front illuminance at an inclination angle θF, s for the directional source to be evaluated; is the transm ittance factor for uniform hemispherical illuminati on on the back TQ, di/0 of screen; EB, hem i is the back illuminance for uniform hem ispherical illum ination of the spectral source to be evaluated; is the transm ittance factor for a directional light source at an inclination TQ, 45/0 angle θB, s = 45 ° on the back of the screen; EB, dircos θB, s is the back illum inance at an inclination angle θB, s for the directional source to be evaluated 5) I f the reflection and transm ission coefficients of the transparent OLED display are not dependent on the rendered colour, then L m ax, am b = L m in, am b The spectral radiance version of Formula (1 9) has the sam e form 6) The actual values to be used to calculate the ambient contrast ratio shall be specified based on the intended application Recomm end values are given in Table and 7) All values used to calculate the ambient contrast ratio shall be recorded in the test report 7 Di spl ay am bi en t col ou r m easu rem en t Pu rpose The purpose of this m ethod is to determ ine the on-screen ambient colour of a transparent OLED display m odule under defined indoor or daylight illum ination conditions NOTE I f the OLED exhibits significant PL , then the am bien t contrast ratio calcul ation is onl y val id for th e sam e illum ination spectra and geom etry used to m easure the transm ission an d refl ection coefficients 2 M easu ri n g d i ti on s For this m easurem ent, the following conditions shall be applied a) Apparatus: ) spectroradiometer that can measure spectral radiance; 2) driving power source; 3) driving signal equipm ent; 4) directional light source; 5) integrating sphere or sam pling sphere with a stabilized light source b) I lluminance condition: ) the standard am bient illum ination conditions for an indoor room or clear sky daylight shall be used, as specified in Clause 2) additional illum ination conditions may also be used, depending on the application c) Except for the standard ambient illum ination conditions, all other conditions are the standard conditions – 34 – I EC 62341 -6-4: 201 © I EC 201 M easu ri n g meth od G en eral For this m easurem en t, the fol lowin g m eth od sh al l be appl ied The chrom aticity of a d ispl ay un d er h em ispherical d iffuse an d d irecti on al i l lu m inati on d iti ons is a com bi n ati on of the d ispl ay’ s i ntri nsic l ig h t em ission, transm itted and refl ected am bi en t l i gh t – – – The am bi en t chrom atici ty of a d ispl ay at a gi ven colour state Q (e g wh ite, bl ack, red , green, or bl ue screen) u n der il lum i nation d ition s is d eterm in ed by i ts eq u i val en t d isplay am bi en t tristim ul us values These valu es can be obtain ed from darkroom m easurem en ts at th e d esired col our state, com bi ned wi th transm ission an d refl ecti on m easurem ents of th e displ ay u n der hem isph erical d iffuse an d d irection al source i ll um ination cond i tions at th at colour The m easuri ng m eth ods used to ch aracteri ze the transm issi on and refl ection coeffici en ts for th e d isplay u n d er hem isph erical an d d irecti on al i l l um in ati on are gi ven i n Cl auses an d 3.2 M easu rem en t an d cal cu lati on s For th is m easurem ent, th e fol lowi ng m easurem ent an d calcu lati ons shal l be appl i ed ) The total am bi en t spectral rad iance L Q, tot (λ ) with transm ission an d refl ecti on contri buti ons i ncl u ded wi l l be: L Q, tot ( λ ) = LQ ( λ ) + LQ,amb ( λ ) (21 ) where L Q (λ ) L Q, am b (λ ) is th e d arkroom spectral rad iance of the transparent OLED d isplay m easured at the centre and perpend icular to the d ispl ay for th e d esired col our state Q ; is the spectral form of Form ula (1 9) 2) The actual values to be used to calculate the total am bient spectral rad iance for a given ren d ered display colour shal l be specified based on the inten ded application Recomm end values are given in Tabl e and 3) Al l values used to calcu late the total am bien t spectral rad iance shall be record ed in the test report 4) The effective d isplay d ayligh t tristim ul us valu es of the d isplay under these illum in ation cond itions are: where x XQ, tot = 683  LQ, tot ( λ ) x( λ )dλ (22) YQ, tot = 683  LQ, tot ( λ ) y( λ )dλ (23) ZQ, tot = 683  LQ, tot ( λ ) z( λ )dλ (24) λ λ λ (λ ) , y(λ ) , and z(λ ) are the colour m atch in g functions (see CI E 5-2004) I EC 62341 -6-4: 201  I EC 201 – 35 – 5) The am bient 931 CI E x and y chromaticity coordinates of the em itting display at the desired colour state Q under the specified illum ination conditions are: xQ = XQ, tot XQ, tot + YQ, tot + Z Q, tot (25) yQ = YQ, tot XQ, tot + YQ, tot + ZQ, tot (26) – 36 – I EC 62341 -6-4: 201  I EC 201 Annex A (normative) Alternative method for measuring the hemispherical transmittance factor of a transparent OLED display A.1 Purpose An alternative m ethod is described to m easure the hem ispherical transmittance factor of a transparent OLED display This shall be the preferred method if the presence of the OLED display against the sphere significantl y changes the spectral irradiance on the sphere walls I t is also necessary to use this method if the OLED display needs to be measured in its on state A.2 Measuring conditions For this m easurem ent, the following conditions shall be applied a) Apparatus: ) spectroradiometer as defined in 3.2; 2) a smooth broadband light source shall be used to produce sufficient spectral irradiance from 380 nm to 780 nm inside a sampling sphere The intensity at each wavelength in that range should be also stable to less than %; 3) a sam pling sphere shall be used to im plement uniform hem ispherical diffuse illum ination conditions The configuration shall follow the standard 8° to 0° detection geom etry, which is shown in Figure A General guidance is given in I EC 62341 -6-2 for m aking optical measurem ents using a sampling sphere b) I lluminance condition: the standard ambient illumination should be used, such as CI E illuminant A, or CI E Dayli ght I llum inants, as recomm ended in Table or defined in the test specification c) The m easurements will be performed in a dark room with an OLED display rendering the desired colour Q I t should be noted that it is not uncom mon for the OLED transm ission properties to be largel y invariant with the rendered colour I f that can be demonstrated, then the trasm ission properties can be measured with the display turned off A.3 Measuring the transmittance For this measurem ent, the following method shall be applied I EC 62341 -6-4: 201  I EC 201 – 37 – Display Lam p L wal l L STD LT Detector Sam pling sphere White standard IEC F i g u re A – M eas u re m en t g e om etry u s i n g a s am p l i n g s ph e re ) A spectroradiometer is aligned in such a way that its field of view is centred on the detector port (left port in Figure A ), and its measurement field is focused and centred on the sam ple port (right side of sam pling sphere) 2) Place a white reflectance standard, of known spectral reflectance ρ std ( λ ) for hem ispherical illumination, against the sam ple port After the light source has stabilized, m easure the spectral radiance of the reflectance standard L std ( λ ) 3) Rotate the spectroradiom eter about the detector port such that the m easurem ent field is positioned on the inner wall of the sampling sphere adjacent to the sample port M easure the spectral radiance of the sphere inner wall L wall ( λ ) The spectral reflectance of the sphere inner wall ρ wall ( λ ) is obtained by: ρ wall ( λ ) = ρ std ( λ ) ⋅ L wall ( λ ) L std ( λ ) (A ) 4) Place the back of the transparent display against the sample port of the sampling sphere Turn on the display to the desired colour state Q , where Q m ay be off, red, green, blue, etc Allow the display to stabilize 5) Measure the spectral radiance of the sphere inner wall L Q, wall ( λ ) under sphere illum ination with the display rendering a colour Q 6) The spectral irradiance EQ ( λ ) on the display from the sphere hem ispherical illum ination is given by: EQ ( λ ) = πLQ, wall ( λ ) ρ wall ( λ ) (A 2) NOTE To ensure m easu rem ent i nteg rity, the spectral i rradiance EQ ( λ ) is d om inated by the illum inati on ori ginati ng from the sphere li gh t source 7) Move the spectroradiom eter to the front of the transparent OLED display Align the spectroradiom eter normal to the display surface, and centre the measurem ent field in the centre of the sample port The LMD distance to the display shall be obtained from the test specification, otherwise it shall be 0, m M easure the total spectral radiance L Q, T ( λ ) transmitted through the transparent OLED display 8) Maintain the position of the transparent OLED display, and remove the sphere While the display is still rendering the same colour Q , m easure the spectral radiance L Q ( λ ) of the transparent OLED display in a dark room I f the display emission is stable and reproducible, the dark room m easurement can be done independentl y of the sphere measurem ents – 38 – I EC 62341 -6-4: 201  I EC 201 9) The hemispherical spectral transmittance factor TQ, di/0 ( λ ) of the transparent OLED display with the display rendering a colour Q is given by: TQ, di/0 ( λ ) = π (LQ, T ( λ ) − LQ ( λ )) EQ ( λ ) (A 3) The lum inous transm ittance factor TQ for an y CI E-defined illumination spectrum ECI E ( λ ) can be calculated using the following formula: ∫ T (λ )E (λ )V(λ )dλ ∫λ E (λ )V(λ )dλ TQ = λ Q CIE CIE where V( λ ) is the photopic luminous efficiency function as defined in CI E 5-2004 (A 4) I EC 62341 -6-4: 201  I EC 201 – 39 – Bibliography International [1 ] I nformation display measurements standard (I DMS), version 03, Committee for Display Metrology, Society for I nform ation Display, 201 [2] ASTM D1 003-00, [3] I SO 3468-1 , Plastics – Determination of the total luminous transmittance of transparent materials – Part 1: Single-beam instrument [4] I SO 4782, [5] I TU-R BT 709-6: 201 5, Parameter values for the HDTV standards for production and international programme exchange [6] I EC 62341 -6-3: 201 2, [7] Standard test method for haze and luminous transmittance of transparent plastics, 2000 Plastics – Determination of haze for transparent materials Organic light emitting diode (OLED) display – Part 6-3: Measuring methods of image quality E F Kelley, M Lindfors, and J Penczek, measurement methods and daylight readability, p 01 9-1 030 (2006) Display daylight ambient contrast J Soc I nformation Display, V 4, [8] AN SI /I ESN A RP-1 -04, American National Standard Practice I lluminating Engineering Society of N orth America (I ESN A), 2004 for Office Lighting, [9] Using model in ASTM G1 97, [1 0] The I ESN A Lighting H andbook: Reference and Application, 9th Ed (2002) [1 ] CI E Publication No 44, Absolute Methods for Reflection Measurement, Commission Internationale de l’Eclairage (International Commission on Illumination), 979 reprinted Standard Table for Reference Solar Spectral Distributions: Direct and Diffuse on 20º Tilted and Vertical Surfaces, 2008 990 For example of sam pling sphere, see the Sharp-Little method CIE Colorimetry – Part 1: Standard Colorimetric Observers [1 2] CI E S 01 4-1 /E: 2006, [1 3] I EC 60050-845: 987, International Electrotechnical Vocabulary (IEV) – Part 845: Lighting (available at www electropedia org ) _ INTERNATIONAL ELECTROTECHNICAL COMMISSI ON 3, rue de Varembé PO Box 31 CH-1 21 Geneva 20 Switzerland Tel: + 41 22 91 02 1 Fax: + 41 22 91 03 00 info@iec.ch www.iec.ch