Optical Measurement of High-Power Leds

2010 CIE Division 2

TC 2-63 Meeting

Optical Measurement of High-Power LEDs

TR: To develop a CIE recommendation on methods for the operation of high-power LEDs in DC and in pulse mode, at specified junction temperatures, for optical measurements.

10:45 am - 12:15 pm, Wednesday, September 1, 2010

Conference RoomHB30

METAS, Bern, Switzerland

1. Welcome

- members and guests / sign-in

2. Summary of last(first) TC meeting in Budapest, Hungary

Held on June 1, 2009. 20 members, 42 attendees.Topics discussed:

measurement methods, new eHP LEDs and AC LEDs,test commercial instruments, standard development in IES, JEDEC, TAIWAN, CHINA, BELGIUM,TC2-63 scope, preferred method for determination ofVf(single point or curve fitting), necessary or not to choose a standard Tj andTa as the international standard condition, and aging and stability concerns when using Vf of an LED as the long-term Tj monitor.

3. Update on measurement techniques and instruments

- NIST Small Business Innovation Research (SBIR) project for development of commercial instruments for measurement of HP LEDs.

- True junction temperature setting for measurement of AC LEDs.

- Measurement of extremely HP LEDs (50 W or higher).

- Continuous pulse method for measurement of HP LEDs

- Measurement of remote phosphor LEDs.

* You are encouraged to share your research in the meeting. Please prepare your slides and let me know.

4. Input and update from national and international standard bodies

- IESNA (Y. Ohno)

.....

* Please let me know if you have an update or/and if have suggestions to the TC2-63.

5. Contents of the document

1) SCOPE

1.1 Serve testing laboratories, does not serve factory's production lines (TC2-64):

1.2 Coversmeasurement of photometric, radiometric, and colorimetric quantities of

* single-chip LEDs (UV, VIS and IR), chip-level,or board-level multi LED arrays where the junction temperatures of all LEDs are virtual the same.Mayalso include remote phosphor LEDs.

* chip-level AC LEDs

Does not cover:

LED clusters (TC2-50), LED module, LED lamps,and large area LEDs such as OLEDs, etc.

1.3 Includes both DC and pulse methods. Pulse method is for measurement of LEDs such as un-mounted LEDs, extremely high- power LEDs, ...

*** Relationship to the CIE127-2007

Optical measurement may be similar, However,

1) HP LED intensity can and should be made at much longer distance, may lead to a "true" intensity.

2) HP LEDs are much larger because of their heat sinks, requiring large spheres.For HP LEDs, half-moon spheres might be useful.

3) HP LEDs have much higher optical power,thus spectroradiometers may be widely used with acceptable measurement uncertainties.

*** Can this document be published as part 1 (set and control LED measurement conditions) and part 2 (measurement of optical quantities) to meet the urgent need?

2)INTRODUCTION

3)NORMATIVE REFERENCES

4)DEFINITIONS

5)OPERATION OF HP LEDs

5.1Operation of LEDs - DC method

5.2Operation of LEDs - Pulse method

5.2Operation of AC LEDs

6)MEASUREMENT OF HP LEDs

6.1LED Intensity

6.2Total luminous flux

6.3Total radiant flux

6.4LED color

7)CHARACTERIZATION OF MEASUREMENT SYSTEMS

7.1Integrating sphere

7.2Goniometer

7.3Spectroradiometer (TC2-51)

7.3.1Stray light

7.3.2 bandpass (TC2-60)

8)CALIBRATION STANDARDS

9)CALIBRATION OF MEASUREMENT SYSTEM

10)MEASUREMENT UNCERTAINTIES

APPENDIX

6. Work plan

...