Patent ID: 6139156
Filing Date: 2000-10-31
Classification: G02B,G03B,H04N

Abstract:
A light source device comprising:a pillar optical element including an incident end face and an emitting end face;a lamp;a transmissive condenser lens condensing light emitted from said lamp in the vicinity of the incident end face of said pillar optical element; andfirst lens forming an image of said emitting end face of said pillar optical element, said first lens being effective to focus the image of said emitting end face of said pillar optical element at a surface to be irradiated;wherein said pillar optical element is formed as a single solid element and includes a tapered portion on a side of said incident end face and a non- tapered pillar portion on a side of said emitting end face, a cross-sectional area of the tapered portion continuously increasing from the incident end face toward the emitting end face and a cross-sectional area of the non-tapered pillar portion being constant, wherein lateral surfaces of said pillar optical element act to provide substantially total internal reflection and wherein a length of the tapered portion LT, a height of the incident end face H1, a height of the emitting end face H2, and a taper angle .beta., are related by: .beta.=tan.sup.-1 {(H2-H1)/(2.multidot.LT)}.