Multiemitter 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 a single spatial light modulator is mainstream in the displays so far. This projector uses the laser light sources under pulse with duty of 20% to 50%. We improve a triple-emitter red color 638-nm high-power broad area laser diode (LD) for this application. Countermeasures are adopted to improve the output power characteristics and strengthen the facet to the fatal degradation. The improved triple emitter shows 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 is increased by 4.1% compared to our former one. The peak wall plug efficiency reaches to 41.6% under 25°C. The long-term aging test is also performed. Mean time to failure of the improved LD is estimated 72,000 h under the output of 3.5 W, pulse condition with duty of 30%. The value is ∼3.3 times longer than that of the former.