Strauss introduce that the green source in a pico-projector producing a 100 lumen brightness must meet the requirements as following: an emission wavelength of 515 nm; an output power of at least led linear high bay light; a wall plug efficiency of 5 percent or more; and, in both the lateral and vertical directions, a single mode output. If a shorter wavelength source is used – for example, a 505 nm laser – the power output requirements are higher.
In close collaboration with the Fraunhofer Institute for Reliability and Microintegration (IZM) Heraeus has continued to work on the design optimization of its SCB substrates for LEDs. Quite apart from the results already gained in the field of short duration LED applications, the focus this time was put on applications of a longer duration. The aim now was to lower the junction temperature TJ of the applied LED chips and so enable a direct readout relating to the overall effectiveness of the thermal management in comparison to other substrate solutions. (The junction temperature is the temperature which arises in the barrier layer and thus its relevance to the ageing process of the semiconductor).
The theoretical FEM simulation had already prescribed at which parameters the junction temperature could be lowered by several degrees Celsius. Armed with this data, together with best practice approaches and optimum simulation results, the engineers laid down the sample substrate and assembled it in line with the predefined design.
The subsequent (de facto) thermal analysis of the led high bay light at the IZM proved that thanks to the optimized choice of material and the simultaneously defined and perfected design the TJ sank by as much as 12 °C in comparison to standard designs for short duration applications when operating under an electrical load of 1.5 W. This drop in temperature has an extremely positive effect on the durability and brightness of the HBLED.
In close collaboration with the Fraunhofer Institute for Reliability and Microintegration (IZM) Heraeus has continued to work on the design optimization of its SCB substrates for LEDs. Quite apart from the results already gained in the field of short duration LED applications, the focus this time was put on applications of a longer duration. The aim now was to lower the junction temperature TJ of the applied LED chips and so enable a direct readout relating to the overall effectiveness of the thermal management in comparison to other substrate solutions. (The junction temperature is the temperature which arises in the barrier layer and thus its relevance to the ageing process of the semiconductor).
The theoretical FEM simulation had already prescribed at which parameters the junction temperature could be lowered by several degrees Celsius. Armed with this data, together with best practice approaches and optimum simulation results, the engineers laid down the sample substrate and assembled it in line with the predefined design.
The subsequent (de facto) thermal analysis of the led high bay light at the IZM proved that thanks to the optimized choice of material and the simultaneously defined and perfected design the TJ sank by as much as 12 °C in comparison to standard designs for short duration applications when operating under an electrical load of 1.5 W. This drop in temperature has an extremely positive effect on the durability and brightness of the HBLED.
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