Koji Uchida

Diamond Sensors Durable for Continuously Monitoring Intense Vacuum Ultraviolet Radiation

Photoconducting sensors are fabricated using radiation-hard diamond films to measure the intensity of vacuum ultraviolet (VUV) radiation. They are composed of a pair of interdigitated Pt electrodes on highly oriented diamond surfaces. The sensors are examined as monitors of the intensity of VUV radiation (λ=172 nm) from xenon excimer lamps with an output power of greater than 10 mW/cm2. It was demonstrated that the diamond sensors have practical durability: the output signals from the sensors are reproducible and stable under a continuous irradiation from the xenon lamps for more than 500 h.

High Brightness Full Color LEDs

A new Multi-Layer type full color LED, capable of mixing different luminous wavelengths to radiate many different colors of light (visible also from a short distance), at high levels of efficacy. Excellent luminous intensity, has been demonstrated by the prototype. Values of 35 cd white light have been achieved using multi-layered blue, red and green chips, at a current of 20 mA per chip.