Optical Measurement of High-Power LEDs
|Publication Date:||1 January 2017|
This technical report deals with methods used by calibration and testing laboratories for the measurement of optical quantities (including photometric, radiometric, and colorimetric quantities) of HP-LEDs, with focus on small uncertainties. The document covers measurement of HP-LEDs under DC operation only with the thermal condition referring to their junction temperatures. It does not cover those pulse methods with focus on measurement speed for testing facilities that perform fast measurement of a large number of LEDs (e.g. testing facilities used in LED production lines). Such methods are described in the CIE Technical Report "High-Speed Testing Methods for LEDs" (CIE 2017).
This document covers all single-diode HP-LEDs (including large-die HP-LEDs where the junction temperature may be different across the die) . It also covers multiple-diode HP-LEDs (where multiple diodes are electrically connected in series or parallel, or both in series and parallel) as long as the total forward voltage is accessible, which include single-die, multiplediode HP-LEDs, such as high-voltage LEDs (HV-LEDs) where many micro LEDs are integrated onto a single substrate, and multiple-die, multiple-diode HP-LEDs, such as chip-onboard (COB) HP-LEDs where multiple LED dies or surface-mounted device (SMD) LEDs are packaged onto a single metal-core printed circuit board (MCPCB) or a ceramic board. In the case of a large-die HP-LED or multiple-diode HP-LED the junction temperature used as the thermal reference is the average junction temperature. For phosphor-converted white HPLEDs it covers both the contact phosphor type where phosphor is coated directly on the LED die and the remote phosphor type where phosphor is thermally insulated from the LED die.
This document does not cover AC-driven LEDs, organic light emitting diodes (OLEDs), LED modules, LED light engines, LED lamps, and LED luminaires. Those LED products are covered in other CIE publications, partly still in preparation. In particular:
- Characterization of AC-driven LEDs is described in the report of CIE TC 2-76 "Characterization of AC-driven LED Products for SSL Applications", currently still in preparation.
- LED products that comprise multiple dies or packages, and where the forward voltage is not accessible, are within the scope of the report of CIE TC 2-50 "Measurement of the Optical Properties of LED Modules and Light Engines", currently still in preparation.
- Organic LEDs (OLEDs) are covered by the report of CIE TC 2-68 "Optical Measurement Methods for OLEDs used for Lighting", currently still in preparation.
- The international standard CIE S 025/E:2015 deals with LED lamps, LED luminaires and LED modules (CIE 2015b).