Nichia Corp. has developed surface-mount white LEDs achieving luminous intensity fifty percent higher than current parts. The increased brightness results from a more efficient conversion of electricity to emitted white light, making the part ideal for back-lighting of full-color LCD screens in battery powered mobile devices.
Full-color LCD screens, which require a white light source, are becoming more common in a variety of battery powered mobile devices. The most common mobile devices with full color displays are personal digital assistants, handheld video cameras, and digital still cameras. Cellular telephones with full-color LCD screens are also becoming commonplace, particularly in Japan. As a back-light source, white LEDs offer the advantages of compact size, durability, low power consumption, and long lifetime.
"Color displays have always been a big improvement over black and white," said Noboru Tazaki, Managing Director and General Manager of Nichia's Optoelectronics Products Division. "Because they emit more light from less battery power, our new white LEDs make full-color LCD screens practical for a wider variety of mobile devices."
First samples for the new white LED will be available for Nichia's NSCW215 series, a side view surface-mount LED. The improved NSCW215 emits 600 mcd of light and is only 1.0 millimeter in height. An even thinner side view surface-mount LED, with a height of a mere 0.8 millimeters and a full 600 mcd, will also be available. With no increase in power consumption, the higher brightness and lower profile of both parts make them ideal for back-lighting color LCD screens in mobile devices. Engineering samples will be available in this quarter; volume production is targeted for Q2 of calendar 2002.
Nichia developed the white LED in the mid-1990's by combining its high quality phosphor with its recently commercialized indium gallium nitride (InGaN) blue LED. Nichia found that when blue light from an InGaN die passes through a thin phosphor coating, a portion of the blue light is down-converted to yellow light. This yellow light mixes with the remaining blue light from the InGaN die to create bright white light. Increased brightness of Nichia's white LEDs was achieved by improvements to both Nichia's InGaN die and Nichia's proprietary phosphor coating.
Nichia was established in Japan in 1956 to manufacture calcium phosphate used in the production of fluorescent lamp phosphors. Since that time, Nichia has grown in the field of manufacturing and sales of fine chemicals, particularly inorganic luminescent materials (phosphors), high brightness LEDs, and, recently, laser diodes. Nichia is recognized as the world leader in InGaN LED and laser diode technology. Nichia has been issued over 20 patents in eight countries for its white LED technology. Nichia was formerly known as Nichia Chemical Industry Company, Limited. Nichia has operations throughout the world, including Nichia America Corp., a U.S. subsidiary based in Mountville, PA.
For additional information, visit www.nichia.co.jp.