Magnetic Materials and Semiconductors. "The 21 st Century Light" Based on White LED Lighting Technology of Compound Semiconductor.

The technology of white LEDs which is connected with the InxGa1-xN blue LED coated with a YAG : Ce phosphor, has improved the white LED efficiencies to approximately 30 lm/W. We have reported a maximum luminous efficacy of about 40 lm/W using 700 LEDs lighting source at electric power of 5 W. It has been expected that extremely high-brightness white LEDs can significantly replace standard incandescent bulbs. We have also demonstrated an energy saving type street lamp linked with a photovoltaic solar cell using a 10 Cd-class white LEDs array lighting source. An alternative method of making a color conversion white LEDs is provided to produce a true white which can be achieved using three colors from red, green, and blue phosphors excited by ultraviolet (UV) LEDs. In the future, as the efficiency of blue and UV LEDs will be improved, the white LED lamps may replace conventional light bulbs or fluorescent lamps in many applications.