Endoscope objective optical system
First Claim
1. An endoscope optical system comprising,an endoscope objective comprising a negative first lens group, a positive second lens group, a positive third lens group, and a negative fourth lens group, in this order from an object, wherein said positive second lens group and said positive third lens group are moved to vary a distance between them (i) at a short focal length extremity and (ii) at a maximum magnification position without changing the overall length from said negative first lens group to an image plane, and the focal length of said endoscope objective is varied while maintaining an in-focus state.
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Abstract
An endoscope objective optical system includes a negative first lens group, a positive second lens group, a positive third lens group, and a negative fourth lens group, in this order from the object. The positive second lens group and the positive third lens group are arranged to move while the object distance is varied without changing the overall length from the first lens group to an imaging plane. Due to this arrangement, the focal length of the endoscope objective optical system is varied while maintaining an in-focus state.
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Citations
12 Claims
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1. An endoscope optical system comprising,
an endoscope objective comprising a negative first lens group, a positive second lens group, a positive third lens group, and a negative fourth lens group, in this order from an object, wherein said positive second lens group and said positive third lens group are moved to vary a distance between them (i) at a short focal length extremity and (ii) at a maximum magnification position without changing the overall length from said negative first lens group to an image plane, and the focal length of said endoscope objective is varied while maintaining an in-focus state.
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7. An endoscope optical system comprising:
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an endoscope objective comprising a negative first lens group, a positive second lens group, a positive third lens group, and a negative fourth lens group, in this order from an object, wherein said positive second lens group and said positive third lens group are movable to vary a distance between them without changing the overall length from said negative first lens group to an image plane, and the focal length of said endoscope objective is varied while maintaining an in-focus state. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification