Semlight releases LED street light with diamond-like carbon for thermal protection

May 8, 2014
Semlight releases new-generation 65W E40 LED street light using PCB with DLC (diamond like carbon).

Heat dissipation is always a big problem for LED engineers; with temperature incerases the luminance will decrease. The luminous decay will increase also - the light may even burn out.

When LED power rises, heat dissipation is especially a problem. From earlier glass fiber PCB to the latest aluminum substrate PCB, heat dissipation is still a necessity.

Currently, general aluminum substrate PCBs use epoxy as the insulation layer, then make circuits on the epoxy layer. The heat conduction ratio of the epoxy layer( 0.5W/mK) is lower than aluminum (275W/mK) by hundreds of times;, the heat generated on the LED chip is difficult to diffuse.

However, Semilght LED street lights, using PCBs with DLC, which is plated on LED metal basic boards, feature a high-performance heat-transfer plating film; compared to copper (400W/mK), DLC heat conduction ratio is higher, to 500W/mK and above. Moreover insulation performance is excellent, so PCBs with DLC plating achieve a noticeable heat dissipation effect. Semlight has been using PCBs with DLC for its E40 65W LED street lights in mass production, as a replacement for traditional 200W high-pressure sodium or metal halide lighting.

Since adopting PCBs with DLC, Semlight's 65W E40 LED street lights feature the ability to diffuse heat generated on the LED chip instantly, decreasing the junction temperature of the LED so the LED chip keeps working at lower temperature, thus reducing LED luminance decay and extending the street light lifetime.


Jimmy Wu, General manager - Semlight