White is Here! HP weighs in.
HP Introduces White LEDs with Color-Temperature Grading
Lamps in 15° or 30° Viewing Angles Feature 2,000mcd and 800mcd Typical Intensity
Palo Alto, California. Mar. 15, 1999
Hewlett-Packard Company today introduced its first LED lamps to provide a white-light output.
Applications include electronic signs and signals, small-area illumination, legend backlighting and general-purpose indication. Similar phosphor-white LED lamps are already being incorporated into specialized high-reliability low-battery-drain flashlights for emergency and military applications, as well as into plug-in replacements for incandescent lamps.
The LED lamps use InGaN LED chips coated with a YAG (yttrium aluminum garnet) inorganic phosphor to provide a white light which is nominally x=0.31, y=0.32 on the CIE (Commission Internationale de l'Eclairage) 1931 chromaticity diagram. This represents a color temperature of approximately 6500K. Luminous intensities for these LEDs are 2,000 millicandela (mcd) for lamps with 15-degree viewing angle and 800mcd for lamps with 30-degree viewing angle (typical at 20mA forward current).
"LEDs are rugged, energy efficient, and versatile," said Frank Steranka, solid state lighting business manager in HP's Optoelectronics Division. "Traditional colored LEDs have proven themselves in signage, as indicator lights and in automotive lighting. The white LED is important in expanding LED applications toward general lighting, where the opportunities are enormous. HP will follow the 5mm package with additional specialized and higher performance white packages."
... [continued: Chromaticity, CRI, links to product pages, .pdf data sheets]
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