Semiconductor white light sources

Abstract

Semiconductor white light sources presented herein include special combinations of a blue source and a yellow source where these light fields are substantially overlapped. The source of blue light includes a blue emitting semiconductor operating in a conventional manner. However, this blue light source is combined with a special yellow light source and the light produced by each is mixed together. The yellow light source is primarily comprised of a high output ultraviolet emitting semiconductor coupled to a wavelength shifting medium whereby the semiconductor pumps the wavelength shifting medium causing re-emission at longer wavelengths; namely those corresponding to yellow colored light. These two sources operating in conjunction with each other operate to produce higher outputs than those attainable in competitive white light semiconductor systems. In special versions, provision is made whereby the color coordinates may be tuned by a variable current applied to the blue emitting semiconductor.