Illumination optical system for endoscopes

Claim 2

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, each of said at most two lens elements being composed of an inhomogeneous medium in which the refractive index of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis, wherein said cover lens has negative refractive power as a whole and each of said at most two lens elements is provided with a convex spherical surface, toward the object, on the side of the object.

Claim 3

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, each of said at most two lens elements being composed of an inhomogeneous medium in which the refractive index of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis, wherein said cover lens has positive refractive power as a whole and each of said at most two lens elements is provided with a convex spherical surface, toward the object, on the side of the object.

Claim 4

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, each of said at most two lens elements being composed of an inhomogeneous medium in which the refractive index of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis, wherein said cover lens has positive refractive power as a whole and each of said at most two lens elements is provided with a convex spherical surface, toward the object, on the side of the object.

Claim 5

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, each of said at most two lens elements being composed of an inhomogeneous medium in which the refractive index of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis, wherein each of said at most two lens elements is provided with a convex aspherical surface, toward the object, on the side of the object.

Claim 6

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, each of said at most two lens elements being composed of an inhomogeneous medium in which the refractive index of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis, wherein each of said at most two lens elements is provided with a convex aspherical surface, toward the object, on the side of the object.

Claim 7

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, wherein said cover lens has negative refractive power as a whole and each of said at most two lens elements is provided with a concave surface on the side of the exit end face of said fiber bundle and a smooth aspherical surface on the side of the object and has negative refractive power, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis.

Claim 8

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, wherein said cover lens has negative refractive power as a whole and each of said at most two lens elements is provided with a concave surface on the side of the exit end face of said fiber bundle and a smooth aspherical surface on the side of the object and has negative refractive power, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination optical system is larger than that of a center part close to the optical axis.

Claim 9

An illumination optical system for endoscopes according to claim 4, wherein said object side surface has a convex shape toward the object.

Claim 10

An illumination optical system for endoscopes according to claim 4, wherein said object side surface has a concave shape in the center part toward the object and a convex shape in the peripheral part toward the object.

Claim 11

An illumination optical system for endoscopes according to claim 4, wherein said exit end face side surface is formed as a smooth aspherical surface.

Claim 12

An illumination optical system for endoscopes according to claim 7, wherein said exit end face side surface is formed so that the curvature of the peripheral part distant from the optical axis of said illumination optical system is smaller than that of the center part close to the optical axis.

Claim 13

An illumination optical system for endoscopes according to claim 4, wherein said exit end face side surface is formed as a spherical surface.

Claim 14

An illumination optical system for endoscopes according to claim 4, wherein said object side surface is formed as a plane surface in the center part and has a convex shape in the peripheral part toward the object.

Claim 15

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit and face and a cover lens arranged in front of the exit end face of said fiber bundle as that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a convex spherical surface toward the object and a surface nearest the exit end face of said fiber bundle is formed as a smooth convex aspherical surface toward the object.

Claim 16

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit and face and a cover lens arranged in front of the exit end face of said fiber bundle as that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a convex spherical surface toward the object and a surface nearest the exit end face of said fiber bundle is formed as a smooth convex aspherical surface toward the object.

Claim 17

An illumination optical system for endoscopes according to claim 11, wherein said exit end face side surface is formed so that the curvature of the peripheral part distant from the optical axis of said illumination optical system is smaller than that of the center part close to the optical axis.

Claim 18

An illumination optical system for endoscopes, comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a smooth aspherical surface and the other surfaces are each formed as a smooth surface, wherein said cover lens has positive refractive power as a whole and each of said at most two lens elements is provided with a convex aspherical surface, toward the object, on the side of the object, and has positive refractive power, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination optical system is smaller than that of a center part close to the optical axis.

Claim 19

An illumination optical system for endoscopes, comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by the endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a smooth aspherical surface and the other surfaces are each formed as a smooth surface, wherein said cover lens has positive refractive power as a whole and each of said at most two lens elements is provided with a convex aspherical surface, toward the object, on the side of the object, and has positive refractive power, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination optical system is smaller than that of a center part close to the optical axis.

Claim 20

An illumination optical system for endoscopes according to claim 13, wherein each of said at most two lens elements in provided with a plane surface on the side of the exit face of said fiber bundle.

Claim 21

An illumination optical system for endoscopes according to claim 13, wherein each of said at most two lens elements is provided with a smooth aspherical surface on the side of the exit end face of said fiber bundle, said aspherical surface being formed as that the curvature of the peripheral part distant from the optical axis of said illumination is smaller than that of the center part close to the optical axis.

Claim 22

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a convex spherical surface toward the object and a surface nearest the exit end face is formed as a smooth convex aspherical surface toward the exit end face, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination is smaller than that of a center part close to the optical axis.

Claim 23

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of at most two lens elements arranged along an optical axis of said illumination optical system, among lens surfaces of which, a surface nearest the object is formed as a convex spherical surface toward the object and a surface nearest the exit end face is formed as a smooth convex aspherical surface toward the exit end face, said aspherical surface being formed so that the curvature of a peripheral part distant from the optical axis of said illumination is smaller than that of a center part close to the optical axis.

Claim 24

The invention according to any on of claims 4--16, wherein said cover lens is formed as an inhomogeneous medium lens in which the refractive index of the peripheral part is larger than that of the center part.

Claim 25

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of two positive lenses arranged so that their convex surfaces are directed to each other along an optical axis, said two convex surfaces are each formed as a smooth aspherical surface.

Claim 26

An illumination optical system for endoscopes comprising a fiber bundle having an exit end face and emitting light from said exit end face and a cover lens arranged in front of the exit end face of said fiber bundle so that the light emitted from the exit end face of said fiber bundle is irradiated toward an object to be observed by an endoscope in order to illuminate the object to be observed by an endoscope through said cover lens, said cover lens consisting of two positive lenses arranged so that their convex surfaces are directed to each other along an optical axis, said two convex surfaces are each formed as a smooth aspherical surface.

Claim 27

The invention according to claim 18, wherein at least one of the aspherical surfaces of said two positive lenses is formed so that the curvature of the peripheral part distant from the optical axis of said illumination optical system is smaller than that of the center part close to the optical axis.

Claim 28

The invention according to claim 18 or 19, wherein at least one of said two cover lenses is formed as an inhomogeneous medium lens in which the refractive index of the peripheral part is larger than that of the center part.