Light source means for endoscope employing solid state imaging device

Claim 1

An endoscope comprising: an inserting member; a focusing objective lens positioned at a leading end of said inserting member, said objective lens receiving light from a subject to be examined; a solid state imaging device disposed in said inserting member such that an image plane of said imaging device is positioned at the focal plane of said objective lens; a video process means receiving an output from said solid state imaging device for recording in a memory electrical signals from said imaging device corresponding to an image focussed on the image plane of said imaging device and outputting color signals therefrom; display means connected to said video process means for displaying said color signals; a light guide disposed within said inserting members for transmitting light therethrough, said light guide having an input end and an output end thereof, said output end positioned proximal to said objective lens for illuminating said subject; a light source means for projecting light onto the input end of said light guide, said light source means providing sequential color illumination of three different colors to said light guide, including, an illuminating source lamp, a reflector, reflecting light from said source lamp in a parallel beam, a convex lens system disposed in said parallel light path for converging said parallel light, to project said converging light onto said input end of said light guide, a first lens system and a second lens system disposed in the optical path between said convex lens system and the input end of said light guide, said first lens system being positioned between said second lens system and said convex lens system, such that the cross sectional area of the light beam between said first and second lens systems is less than the cross sectional area of the parallel light beam between said reflector and said convex lens system, and such that said light beam between said first and second lens systems has a smaller angle with respect to the optical axis of said lens systems than the light between said convex lens system and said first lens system, a rotary intereference color filter rotatably disposed in the light path between said first and second lens systems, said interference color filter having three different color filters therein such that each of the different color filters are sequentially positioned in the light path during rotation for passing light having specific wavelengths therethrough, and driving means for rotating said rotary intereference color filter to sequentially illuminate the input end of the light guide, and in turn the subject with three colors of illuminating light.