No abstract

Red high power semiconductor lasers are expected to be used for the light source of laser projection display systems. We have achieved 6.6 W CW operation of red semiconductor array lasers at a wavelength of 640nm.The energy conversion efficiency is as high as 29.7% and the degradation rate after 1000-hours is less than 10%. The uniform near field pattern has been obtained by applying index-guided structure for broadstripe laser. We have developed projection display systems including hybrid light sources of UHP lamp and red semiconductor lasers, which can emphasize red color gamut. Speckle noise is dramatically reduced by moving screen that consist of gently rotating diffusion sheet and fixed diffusion plate.

We fabricated the multi-color electroluminescent (EL) device using hydrofluoric (HF) acid solution treated and oxidized silicon (Si) nanoparticles. Strong red luminescence was obtained from the HF treated Si nanoparticles based EL device under a low forward bias of 4.0 V. On the other hand, green and blue luminescence, which could be seen with naked eye under room illumination, was observed for the oxidized Si nanoparitcles based EL device at the forward bias below 9.5 V, because of reduction of size due to oxidation onto the Si nanoparticle surface. Furthermore, the red/green/blue lights showed good stability for aging of a long period of time in air by the formation of oxidized layer on the surface. These results indicate that the EL devices developed in this study can realize as application to future flat panel display.