Assessment of isothermal electro-optical-thermal measurement procedures for LEDs

Rapid growth of Solid-State Lighting market has been supported by progress in Light Emitting Diode (LED) technology. Strong competition requires that lighting product development cycle should be shorter and more effective. Optimal design of a LED luminaire in major degree depends on thermal-electro-optical properties of LEDs in use. These properties are required to be accurately characterized and well predicted for various operating conditions of the LEDs within luminaire in close interaction with other parts of the system. Delphi4LED project [1] aims at developing standardised method to create multi-domain (thermal, electrical, and optical) compact models from the measurement data. Boundary-independent, accurate and well junction temperature-controlled iso-thermal electro-optical characterization procedure for LED samples is required to obtain highly reliable and representative data sets as an input for the compact model. Often, thermal and optical characterization experiments are performed separately at dedicated equipment. In this paper, we report the results of our evaluation and experimental verification of various sources for uncertainties and inaccuracies originated from separation of thermal and optical measurement procedures.