Multi-emitter 638-nm high-power broad area laser diodes for display application

Laser based displays have gathered much attention because only the displays can express full color gamut of Ultra- HDTV, ITU-R BT.2020. There are many types of laser based displays. A projector with single spatial light modulator (SLM) is a main stream in the displays so far. This projector uses the laser light sources under pulse with duty of 20- 50 %. We improved a triple-emitter 638-nm high-power broad area (BA) laser diode (LD) for this application. Countermeasures were adopted to improve the output power characteristics and strengthen the facet to the fatal degradation. The improved triple emitter showed the output of 5.0 W at the injection current of 5 A under pulse with duty of 30%, case temperature of 25°C. The output was increased by 4.1% compared to the former. The peak wall plug efficiency reached to 41.5% under 25°C. The long term aging test was also performed. Mean time to failure of the improved LD was estimated 57,000 hours under the output of 3.5 W, pulse condition with duty of 30%. The value was approximately 2.6 times longer than that of the former.