IEC 62595-2-4:2020

Display lighting unit - Part 2-4: Electro-optical measuring methods of laser module

IEC 62595-2-4:2020(E) specifies the electro-optical measuring methods of laser modules with multiple laser devices and an optical output for various displays and display lighting applications which require photometric and colorimetric measurements, covering the wavelength range of 380 nm to 780 nm. The module has multiple laser devices such as edge-emitting laser diodes (LDs), vertical cavity surface-emitting laser diodes (VCSELs), or photon up-conversion laser devices including second-harmonic generation (SHG). The module has an optical output such as an optical fibre, waveguide, light guide, lens unit, or other optics, emitting a laser beam combining the output of the multiple laser devices.

General Information

• Status: Published
• Publication Date: 28-Sep-2020
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 31.120 - Electronic display devices
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: TC 110 - Electronic displays
• Drafting Committee: WG 19 - TC 110/WG 19
• Current Stage: PPUB - Publication issued
• Start Date: 30-Oct-2020
• Completion Date: 29-Sep-2020

Standards Content (Sample)

IEC 62595-2-4 ®
Edition 1.0 2020-09
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 2-4: Electro-optical measuring methods of laser module
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IEC 62595-2-4 ®
Edition 1.0 2020-09
INTERNATIONAL
STANDARD
colour
inside
Display lighting unit –
Part 2-4: Electro-optical measuring methods of laser module

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 31.120, 31.260 ISBN 978-2-8322-8912-9

– 2 – IEC 62595-2-4:2020 © IEC 2020
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 9
3 Terms, definitions, abbreviated terms, and letter symbols . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms and letter symbols . 11
3.2.1 Abbreviated terms . 11
3.2.2 Letter symbols . 12
4 Standard measuring conditions . 14
4.1 Standard measuring environmental conditions . 14
4.2 Standard measuring dark-room conditions . 14
4.3 Safety requirements . 14
4.4 Standard DUT conditions . 15
4.5 Standard LMD requirements . 15
4.6 Standard measurement setup and coordinate system . 17
5 Measuring methods . 20
5.1 General . 20
5.2 Current-light output characteristics . 21
5.2.1 General . 21
5.2.2 I-P and I- P / P characteristics . 21
o o i
5.2.3 CW and PWM operations . 22
5.2.4 Threshold currents (I ) . 23
th
5.2.5 Measurement procedures . 24
5.3 Spectra (wavelength) and chromaticity measurements . 25
5.3.1 General . 25
5.3.2 Measurement procedures . 25
5.4 FFP . 26
5.4.1 General . 26
5.4.2 Monochromatic FFP . 26
5.4.3 Colorimetric FFP . 27
5.5 Monochromatic speckle and colour speckle . 30
5.5.1 General . 30
5.5.2 Monochromatic speckle measurement affected by FFP . 30
5.5.3 Colour speckle measurement affected by FFP . 32
5.6 Temperature dependence . 35
5.6.1 General . 35
5.6.2 High-power LD module . 35
5.6.3 Low-power RGB LD module . 36
5.7 High-speed pulse modulation properties . 37
5.7.1 General . 37
5.7.2 Optical output pulse waveform measurement . 37
Annex A (informative) Laser devices . 40
A.1 Edge-emitting laser diode . 40
A.2 Single- and multi-transverse modes . 41
A.3 Single- and multi-longitudinal modes . 42

A.4 Vertical cavity surface-emitting laser diode (VCSEL) . 43
A.5 Photon up-conversion laser device. 45
Annex B (informative) Structure of laser module . 46
B.1 Monochromatic laser module . 46
B.2 RGB laser module . 47
B.3 Other output optics . 48
Annex C (informative) Narrow-linewidth emission spectra of laser modules . 49
C.1 Spectra of monochromatic high-power LD modules . 49
C.2 Spectra of multi-colour, single-longitudinal mode LD modules . 51
C.3 Spectra of multi-colour, multi-longitudinal mode LD modules . 51
C.4 Chromaticity measurements using a colorimeter . 52
Annex D (informative) Chromaticity accuracy when measuring narrow spectral
linewidth . 53
D.1 General . 53
D.2 Wavelength accuracy to keep chromaticity accuracy < 0,001 or < 0,005 . 53
D.3 Spectral bandwidth to keep chromaticity accuracy < 0,001 . 55
Annex E (informative) Numerical aperture (NA) of fibre . 58
E.1 Fibre NA and maximum divergence angle . 58
E.2 Colour-dependence of fibre NA . 58
Annex F (informative) Conversion of the spherical and Cartesian coordinate systems . 59
Annex G (informative) Centroid wavelength . 60
Annex H (informative) Examples of colour speckle pattern on colorimetric FFPs of
fibre output . 62
H.1 General . 62
H.2 Measured FFP . 62
Annex I (informative) Temperature dependence of LDs . 65
I.1 Formulation of the thermal performance of LD chips . 65
I.2 Calculated examples of I-P characteristics . 66
o
I.3 Temperature dependence of emitting wavelengths . 69
I.4 Temperature dependence of colour speckle and FFP . 69
Annex J (informative) Eye diagram . 71
J.1 Eye diagram . 71
J.2 Examples of measured eye diagrams . 72
Bibliography . 73

Figure 1 – Measurement setup and coordinate system (spherical) . 18
Figure 2 – Measurement setup and coordinate system (Cartesian) . 19
Figure 3 – Measurement setup and coordinates for speckle-related optical performance . 20
Figure 4 – Example of I-P and I- P / P characteristics . 22
o o i
Figure 5 – Pulse repetition waveforms of PWM drive with respect to duty cycle . 23
Figure 6 – I and I-P characteristics . 24
th o
Figure 7 – Example of measured colorimetric FFP . 29
Figure 8 – Example of conversion of the measured speckle data on the FFP into data
on a uniform pattern . 31
Figure 9 – Example of conversion of measured normalised illuminance data of colour

speckle on the FFP into data on a uniform pattern . 33

– 4 – IEC 62595-2-4:2020 © IEC 2020
Figure 10 – Example of conversion of measured colour speckle chromaticity data on
the FFP into data on a uniform pattern . 33
Figure 11 – Temperature dependence measurement setup for high-power laser

modules . 36
Figure 12 – Temperature dependence measurement setup for low-power laser modules . 37
Figure 13 – Measurement setup for output pulse waveform . 38
Figure 14 – Example of input/output pulse waveforms . 38
Figure A.1 – Schematic structure of narrow-stripe edge-emitting laser diode. 40
Figure A.2 – Schematic structure of wide-stripe edge-emitting laser diode
...