Method for Heat Flux Measurement on LED Light Engines

In order to ensure the exchangeability of LED light engines in LED based luminaires, the Zhaga consortium develops standard specifications for the interfaces of LED light engines. The complete interface definition consists of the description of a mechanical, optical, electrical and thermal interface. The thermal interface has to ensure a good thermal contact between the engine and the fixture. Next to that, the heat spreading capabilities of both the engine and the fixture have to be taken into account in order to ensure sufficient heat spreading capabilities of complete luminaire. In order to come to a practical interface definition, a number of tests and test devices are proposed. Engines and fixture have to pass these tests in order to become Zhaga compliant. One test is the heat flux measurement on the LED light engine in order to determine the amount of heat that has to be transferred from the engine via the fixture. The second test is a test with a reference thermal engine in order to determine the heat spreading capabilities and the thermal resistance of a fixture. The final test is a test with a reference luminaire in order to determine the heat spreading capabilities of the LED light engine. With these three tests, we can realize a practical thermal interface definition.