Objective lens system for endoscopes
AssigneeOlympus Optical Co., Ltd.
InventorTsutomu Igarashi
Life of this patent
Estimating the term…
Abstract
An objective lens system comprising, in the order from the object side, a first lens group having negative refractive power and a second lens group having positive refractive power, and so adapted as to perform variation of focal length and focusing by shifting the second lens group, with the first lens group kept fixed, in such a manner that magnification of the second lens group satisfies a certain definite condition.
Claims14
An objective lens system for endoscopes comprising, in the order from the object side, a foremost first lens group having negative refractive power and a second lens group having positive refractive power, and so adapted as to perform variation of focal length and focusing at the same time by shifting said second lens group, with said first lens group kept fixed, along the optical axis in such a manner that magnification of said second lens group satisfies the following condition:
- .beta..sub.2T '<-1<.beta..sub.2W '
- wherein the reference symbols .beta..sub.2T ' represents magnification of the second lens group in the longer focal length condition and the reference symbol .beta..sub.2W ' designates magnification of the second lens group in the shorter focal length condition.
Dependencies are inferred from the claim text.