Patent ID: 6254264
Filing Date: 2001-07-03
Classification: G02B

Abstract:
A lighting system for a light guide comprising:an arc-discharge-type light source;a reflector having a parabolic reflecting surface which is arranged behind the light source; and,an optical system for condensing light from the light source onto an end of a light guide, whereinthe lighting system satisfies the following conditions3.ltoreq.f.sub.1.ltoreq.40.8.ltoreq.sin(tan.sup.-1 ((D.sub.S /f.sub.S).times.0.5))/NA2.ltoreq.1.20.ltoreq.B.ltoreq.0.2wheref.sub.1 is the focal distance of the reflector,f.sub.S is the focal distance of the final lens element of the condensing optical system,D.sub.S is the diameter of the luminous flux at the final lens of the condensing optical system,NA2 is the numerical aperture of the light guide, andB is the distance between the focal position of the reflector and the tip of the cathode.