Endoscope objective optical system
AssigneePENTAX Corporation
InventorMinoru Murayama
Life of this patent
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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.
Claims5
An endoscope objective optical system 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 while the object distance is varied without changing the overall length from said negative first lens group to an image plane, and the focal length of said endoscope objective optical system is varied while maintaining an in-focus state.
Dependencies are inferred from the claim text.