Endoscope

摘要

To provide excellent illumination over entire range from near view to distant view to achieve clear observation over entire range from near view to distant view.;Provided is an endoscope including an imaging optical system 3 provided in insertion portion at a distal end thereof and for observing an object to be observed, and a plurality of illumination optical systems 2a, 2b provided in the insertion portion 1 and for distributing the illuminating light emitted from a light source to the object to be observed, the illumination optical systems being directed in the same direction each other to illuminate the same field of view, wherein at least one of the plurality of illumination optical systems is a first illumination optical system 2a having a convex lens, and at least one of the others is a second illumination optical system 2b having a concave lens.

主权项

1. An endoscope comprising:
an imaging optical system provided at a distal end of an insertion portion of the endoscope and for observing an object to be observed; and a plurality of illumination optical systems provided in the insertion portion and for distributing an illuminating light emitted from a light source to the object to be observed, wherein at least one of the plurality of illumination optical systems is a first illumination optical system having a convex lens, and at least one of the others is a second illumination optical system having a concave lens, wherein the first illumination optical system is directed in a same direction as a direction in which the second illumination optical system is directed, emits the illuminating light in a same direction as a direction in which the second illumination optical system emits the illuminating light, and distributes the illuminating light toward a same field of view as a field of view toward which the second illumination optical system distributes the illuminating light, wherein a light distribution characteristic of the first illumination optical system is different from a light distribution characteristic of the second illumination optical system, and wherein the following Conditional Expression is satisfied where a spherical light distribution illuminance function of the first illumination optical system is expressed as α(θ)and a spherical light distribution illuminance function of the second illumination optical system is expressed as β(θ):
α(60°)/β(60°)>2  (1) where the spherical light distribution illuminance function α(θ) is a function representing illuminance when a spherical object is illuminated relative to the first illumination optical system, and the function represents illuminance distribution in a range of exit angle θ of the first illumination optical system where the illuminance is set to 1 when the exit angle θ from a center of the first illumination optical system is 0°; and where a spherical light distribution illuminance function β(θ) is a function representing illuminance when a spherical object is illuminated relative to the second illumination optical system, and the function represents illuminance distribution in a range of exit angle θ of the second illumination optical system where the illuminance is set to 1 when the exit angle θ from a center of the second illumination optical system is 0°.