1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationLCD backlight unitPart 2: Electro-optical measurement methods of LED backlight unitBS EN 62595-2:2013National forewordThis British Standard is the UK implementation of EN 62595-2
2、:2013. It is identical to IEC 62595-2:2012.The UK participation in its preparation was entrusted to Technical Commit-tee EPL/47, Semiconductors.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the neces
3、sary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013.Published by BSI Standards Limited 2013 ISBN 978 0 580 65194 6 ICS 31.120; 31.260Compliance with a British Standard cannot confer immunity from legal obligations.This British Stan
4、dard was published under the authority of the Stand-ards Policy and Strategy Committee on 28 February 2013.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS EN 62595-2:2013EUROPEAN STANDARD EN 62595-2 NORME EUROPENNE EUROPISCHE NORM February 2013CENELEC European Committee for E
5、lectrotechnical StandardizationComit Europen de Normalisation ElectrotechniqueEuropisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2013 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No
6、. EN 62595-2:2013 E ICS 31.120; 31.260 English version LCD backlight unit - Part 2: Electro-optical measurement methods of LED backlight unit(IEC 62595-2:2012) Ecran LCD rtro-clairage - Partie 2: Mthodes de mesureslectro-optiques dun cran retro-clairage DEL (CEI 62595-2:2012) LCD-Hinterleuchtungsein
7、heiten - Teil 2: Elektro-optische Messverfahren fr LED-Hinterleuchtungseinheiten (IEC 62595-2:2012) This European Standard was approved by CENELEC on 2012-11-01. CENELEC members are bound to complywith the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Stand
8、ardthe status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained onapplication to the CEN-CENELEC Management Centre or to any CENELEC member. This European Standard exists in three official versions (Engli
9、sh, French, German). A version in any otherlanguage made by translation under the responsibility of a CENELEC member into its own language and notifiedto the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Au
10、stria, Belgium, Bulgaria, Croatia, Cyprus,the Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany,Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland,Portugal, Romania, Slovakia, Slovenia, Spain
11、, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 62595-2:2013EN 62595-2:2013 - 2 - Foreword The text of document 110/384/FDIS, future edition 1 of IEC 62595-2, prepared by IEC/TC 110“Electronic display devices“ was submitted to the IEC-CENELEC parallel vote and approved byCENELEC as EN 62
12、595-2:2013. The following dates are fixed: latest date by which the document has to be implemented at national level bypublication of an identical nationalstandard or by endorsement (dop) 2013-08-08 latest date by which the national standards conflicting with the document have to be withdrawn (dow)
13、2015-11-01 Attention is drawn to the possibility that some of the elements of this document may be the subject ofpatent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all suchpatent rights. Endorsement notice The text of the International Standard IEC 62595-2:2012 wa
14、s approved by CENELEC as a EuropeanStandard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 61747-1 NOTE Harmonised as EN 61747-1. ISO 11664-1:2007 NOTE Harmonised as EN ISO 11664-1:2011 (not modified). ISO 11
15、664-5:2009 NOTE Harmonised as EN ISO 11664-5:2011 (not modified). BS EN 62595-2:2013- 3 - EN 62595-2:2013 Annex ZA (normative) Normative references to international publicationswith their corresponding European publications The following documents, in whole or in part, are normatively referenced in
16、this document and areindispensable for its application. For dated references, only the edition cited applies. For undatedreferences, the latest edition of the referenced document (including any amendments) applies. NOTE When an international publication has been modified by common modifications, ind
17、icated by (mod), the relevant EN/HDapplies. Publication Year Title EN/HD Year IEC 60050 Series International Electrotechnical Vocabulary(IEV) - - IEC 61747-6 - Liquid crystal and solid-state display devices - Part 6: Measuring methods for liquid crystal modules - Transmissive type EN 61747-6 - IEC 6
18、2595-1-2 - LCD backlight unit - Part 1-2: Terminology and letter symbols EN 62595-1-2 - CIE publication 15 2004 Colorimetry - - BS EN 62595-2:2013 2 62595-2 IEC:2012 CONTENTS 1 Scope . 5 2 Normative references . 5 3 Terms and definitions . 5 4 General measurement conditions . 5 4.1 Standard atmosphe
19、ric conditions for LED BLU 5 4.2 Measuring setup 5 4.3 Warm-up time 6 5 Measurement methods . 7 5.1 Electrical measurement methods . 7 5.1.1 Conditions . 7 5.1.2 Current 7 5.1.3 Voltage 7 5.1.4 Power consumption . 7 5.2 Optical measurement methods 8 5.2.1 Conditions . 8 5.2.2 Luminance . 8 5.2.3 Lum
20、inance uniformity. 8 5.2.4 Spectral power distribution 10 5.2.5 Chromaticity 10 5.2.6 Colour uniformity . 10 5.2.7 Correlated colour temperature . 11 5.2.8 Angular luminance uniformity . 11 5.2.9 Angular colour uniformity . 11 5.2.10 Measurement methods of block-wise BLU 12 Annex A (informative) Pra
21、ctical measurement methods of block-wise BLU . 14 Bibliography 16 Figure 1 Example of measuring setup for LED BLU 6 Figure 2 Example of warm-up characteristic of BLU . 7 Figure 3 Definition of zenith angle and azimuth angle . . 8 Figure 4 Examples of measurement point layout 10 Figure 5 Angular lumi
22、nance uniformity measurement . 11 Figure 6 Example of test pattern (8 10 segments) for block-wise BLU . 12 Figure 7 Example of incoherent point spread function 12 Figure 8 Example of test pattern of incoherent point spread function . 13 Figure 9 Example of test pattern of crosstalk . 13 Figure A.1 M
23、easurement of average slope of incoherent point spread function 14 Figure A.2 Black box pattern for crosstalk measurement using LCD . 15 Figure A.3 Example of crosstalk measurement results using LCD 15 BS EN 62595-2:201362595-2 IEC:2012 5 LCD BACKLIGHT UNIT Part 2: Electro-optical measurement method
24、s of LED backlight unit 1 Scope This part of IEC 62595 series specifies the standard measurement conditions and measuring methods for determining electrical, optical, and electro-optical parameters of LED backlight units for liquid crystal displays. NOTE Other backlights (Cold Cathode Fluorescent La
25、mps (CCFLs), External Electrode Fluorescent Lamps (EEFLs), Hot Cathode Fluorescent Lamps (HCFLs), Carbon Nano Tube (CNT), etc.) are excluded from this standard. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for
26、its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60050 (all parts), International Electrotechnical Vocabulary (available at http:/www.electropedia.org) IEC 61747-6, Liq
27、uid crystal and solid-state display devices Part 6: Measuring methods for liquid crystal modules Transmissive type IEC 62595-1-2, LCD Backlight unit Part 1-2: Terminology and letter symbols CIE publication 15:2004, Colorimetry 3 Terms and definitions For the purposes of this document, the terms and
28、definitions given in IEC 62595-1-2 apply. 4 General measurement conditions 4.1 Standard atmospheric conditions for LED BLU Unless otherwise specified, all tests and measurements for LED backlight unit shall be carried out after sufficient warm-up time for illumination sources and devices under test
29、(see 4.3), under the standard environmental conditions, at a temperature of 25 C 3 C, at a relative humidity of 25 % to 85 %, and at an atmospheric pressure of 86 kPa to 106 kPa. When different environmental conditions are used, they shall be noted in the detail specification (see IEC 61747-6). 4.2
30、Measuring setup DUT, LMD, power source, driving and control devices for LED, and electrical measuring devices should be arranged appropriately for electro-optical measurements for LED BLU. An example of measuring setup is shown in Figure 1. BS EN 62595-2:2013 6 62595-2 IEC:2012 Power supply LMD Back
31、light unit Stage IEC 1673/12 Power supply LMD Backlight unit Stage Dimming control IEC 1674/12 DC power VLEDPower consumption of LED BLU PBLU = VBLU IBLULED converter and controller LED arrays VBLUIBLUILEDPower consumption of LED PLED = VLED ILEDIEC 1675/12 Power source Power meter SMPS DUT IEC 1676
32、/12 Key LMD light measuring device SMPS switching-mode power supply DUT device under test Figure 1 Example of measuring setup for LED BLU 4.3 Warm-up time Transient measurement shall be carried out and recorded until the fluctuations of luminance measured at the centre point of the BLU become less t
33、han the range specified in IEC 61747-6. As in Figure 2, luminance of LED backlights is affected by transient temperature behaviour of LED output. It takes a certain time for LEDs until their junction temperature reach the steady state. All measuring conditions shall be kept constant over the time ra
34、nge of recording. Transient measurement of chromaticity should be carried out in the same manner as in the above. BS EN 62595-2:201362595-2 IEC:2012 7 Time (min) 0 10 20 30 40 50 60 0 0,5 1,0 1,5 RelativeluminanceIEC 1677/12 Figure 2 Example of warm-up characteristic of BLU 5 Measurement methods 5.1
35、 Electrical measurement methods 5.1.1 Conditions BLU shall be placed in the measurement arrangement and it shall be assured that all required conditions are fulfilled. After applying the initial electrical driving conditions (i.e. analogue input voltage(s) or digital input signals) of the BLU and wa
36、iting during the warm-up time specified in 4.3 in order to reach the steady state, the measurement of the electrical quantities of interest should be started. 5.1.2 Current The measurement of input current is performed under standard measuring conditions using current meter shown in Figure 1. 5.1.3
37、Voltage The measurement of input voltage is performed under standard measuring conditions using voltage meter shown in Figure 1. 5.1.4 Power consumption Basically, the measurement of power consumption should be carried out under the standard measuring conditions in 4.1, using a power meter. BS EN 62
38、595-2:2013 8 62595-2 IEC:2012 5.2 Optical measurement methods 5.2.1 Conditions LED BLU to be measured should be placed in the measurement arrangement and it shall be assured that all required conditions are fulfilled. After applying the initial electrical driving conditions to the BLU and after wait
39、ing during the warm-up time specified in 4.3 in order to reach the steady state, the measurement of the optical quantities of interest shall be started. Basically, the measurement of this standard should be carried out at various angles between DUT and LMD. A polar coordinate system (,), with the ze
40、nith denoted by and the azimuth denoted by should be considered (see Figure 3). z y x 3:00 6:00 9:00 12:00 LMD IEC 1678/12 Figure 3 Definition of zenith angle and azimuth angle . 5.2.2 Luminance The measurements should be carried out in the dark room under the standard measuring conditions and for t
41、he design viewing directions. a) Position the DUT. b) Adjust the LMD to the specified viewing direction, according to angles and . c) Supply the value of the input signals to the DUT. Then measure the DUT at position pi to obtain the luminance Lvi (,). (In case of i = 0, the position implies the cen
42、tre of the active area of the BLU.) The LMD should be carefully checked before measurements, considering the following checkpoints: sensitivity of the measured quantity to measuring light; errors caused by veiling glare and lens flare (i.e., stray light in optical system); timing of data-acquisition
43、, low-pass filtering and aliasing-effects; linearity of detection and data-conversion. NOTE CIE publication 69:1987 is available for reference of LMD evaluation procedures. 5.2.3 Luminance uniformity Luminance uniformity, U, is a calculated value of how well the luminance remains constant over the s
44、urface of the active area and it is a closely related to luminance measurement itself. BS EN 62595-2:201362595-2 IEC:2012 9 The luminance uniformity measurement is sensitive to testing positions. Typical layouts of measurement points over the BLU surface are shown in Figure 4. Luminance uniformity,
45、U is calculated using one of the following four formulas which are popularly used industry-wide. vavmvMvMvmvMvmvMvMvmLLL ULLL ULL ULL U=where LvMis the maximum luminance value of all measurement points in Figure 4; Lvmis the minimum luminance; and Lva is the average luminance calculated as:=NiNLL1vi
46、vawhere N is the number of measurement points; and Lvi is luminance of an arbitrary point. Typical measurement procedures of luminance uniformity U are as follows. At first, specified input current and voltage are supplied to the BLU to be measured. Secondly, luminance is measured at each point of t
47、he BLU (5, 9, 13 or 25 points). Basically, this measurement is carried out usually at normal angle, however, the other angles can be also considered for certain purposes. BS EN 62595-2:2013 10 62595-2 IEC:2012 (c) Layout of 9 points (b) Layout of 13 points (a) Layout of 25 points (d) Layout of 5 poi
48、nts V/10V/4V/4V/4V/4VV/10H/4 H/10 H/4 H/4 HH/4 /10 H V/10V/4V/4V/4V/4VV/10H/4 H/10 H/4 H/4 HH/4 /10 H V/4V/4VH/4 H/4 H V/4V/4VH/4 H/4 H IEC 1679/12 IEC 1680/12 IEC 1681/12 IEC 1682/12 Figure 4 Examples of measurement point layout 5.2.4 Spectral power distribution A spectral power distribution S() is
49、 measured using a spectrometer or an equivalent optical instrument. The measuring procedures are basically in accordance with 5.2.2 and 5.2.3. 5.2.5 Chromaticity CIE 1931 chromaticity coordinates (IEC 60050-845:1987,845-03-28), x, y, z on the BLU surface of the active area are obtained using the tristimulus values, X, Y, Z calculated from measured spectral power distribution S() given in 5.2.4 (see IEC 62595-1-2). Basica
