Display lighting unit - Part 2-2: Measuring methods of LED light bars used in LCD BLUs

IEC 62595-2-2:2018(E) specifies the standard measurement conditions and measuring methods for determining electrical and optical performances of LED light bars with white LEDs used in LCD backlight units.

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IEC 62595-2-2 ®
Edition 1.0 2018-02
Display lighting unit –
Part 2-2: Measuring methods of LED light bars used in LCD BLUs
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IEC 62595-2-2 ®
Edition 1.0 2018-02
Display lighting unit –
Part 2-2: Measuring methods of LED light bars used in LCD BLUs

ICS 31.120; 31.260 ISBN 978-2-8322-5338-0

– 2 – IEC 62595-2-2:2018 © IEC 2018
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, abbreviated terms and letter symbols . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 6
3.3 Letter symbols (quantity symbols/unit symbols) . 7
4 Measuring configuration . 7
4.1 General . 7
4.2 Light measuring device (LMD) . 8
4.2.1 Luminance meter . 8
4.2.2 Spectroradiometer . 8
4.2.3 Colorimeter . 8
4.3 Sample stage . 9
5 Measuring conditions . 9
5.1 Standard measuring conditions . 9
5.2 Electrical driving conditions. 9
5.3 Warm-up time . 9
5.4 Dark room conditions . 9
5.5 Standard thermal conditions . 9
5.6 Setting conditions . 9
5.7 Mechanical alignment condition . 9
6 Measuring methods . 10
6.1 Electrical parameters . 10
6.1.1 Purpose . 10
6.1.2 Measuring conditions . 10
6.1.3 Measuring method . 10
6.2 Luminance distribution profile . 10
6.2.1 Purpose . 10
6.2.2 Measuring conditions . 10
6.2.3 Measuring method . 10
6.2.4 Report . 12
6.3 Chromaticity and colour uniformity . 13
6.3.1 Purpose . 13
6.3.2 Measuring conditions . 13
6.3.3 Measuring method . 13
6.3.4 Report . 13
7 Test report . 14
Bibliography . 15

Figure 1 – Example of measuring system and arrangement for LED light bar . 8
Figure 2 – Example of LED light bar set and mechanical origin alignment . 10
Figure 3 – Example of 2D luminance distribution on the diffuser plate with lit LED light
bar . 11

Figure 4 – Example of the luminance distribution profiles along the x- and y-axes . 12
Figure 5 – Example of the luminance distribution profiles along the x–axis, L (x, 0) . 12
Table 1 – Letter symbols (quantity symbols/unit symbols) . 7

– 4 – IEC 62595-2-2:2018 © IEC 2018
Part 2-2: Measuring methods of LED light bars used in LCD BLUs

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International Standard IEC 62595-2-2 has been prepared by IEC technical committee 110:
Electronic display devices.
The text of this International Standard is based on the following documents:
CDV Report on voting
110/890/CDV 110/932A/RVC
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 62595 series, published under the general title Display lighting
unit, can be found on the IEC website.

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the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
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– 6 – IEC 62595-2-2:2018 © IEC 2018
Part 2-2: Measuring methods of LED light bars used in LCD BLUs

1 Scope
This document specifies the standard measurement conditions and measuring methods for
determining electrical and optical performances of LED light bars with white LEDs used in
LCD backlight units.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 62595-1-2, Display lighting unit – Part 1-2: Terminology and le

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