Patent ID: 6762551
Filing Date: 2004-07-13
Classification: C09K,H01J,H01L,Y02B

Abstract:
A white light source comprising an ultraviolet-visible excitation light generation unit for generating ultraviolet light and first visible light having a wavelength of from 400 nm to 500 nm; and a fluorescence generation unit having a phosphor layer for generating second visible light upon irradiation of the ultraviolet-visible light generated from the ultraviolet-visible excitation light generation unit as excitation light,the white light source yielding white light by mixing the first visible light from the ultraviolet-visible excitation light generation unit and the second visible light from the fluorescence generation unit, wherein the phosphor layer comprises a red light emitting phosphor represented by following Compositional Formula (1): (Ca1âˆ’aâˆ’bSraEub)S:Mcâ€ƒâ€ƒ(1) wherein a, b and c satisfy the following conditions:0&lE;a<1.0, 0and M is a dopant element having an absorption of excitation energy in a range from 350 nm to 500 nm.