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US 4,101,196 AGranted
Objective optical system for endoscopes
AssigneeOlympus Optical Co., Ltd.
InventorToshihiro Imai
Life of this patent
Estimating the term…
Abstract
An objective optical system for endoscopes comprising a cylindrical light-focusing heterogeneous medium, for which refractive index distribution is expressed by the following formula and which is arranged on the object side of an image-transmitting optical fiber bundle. n = n.sub.0 (1 - 1/2.alpha.R.sup.2)
Claims3
An objective optical system for endoscopes comprising an optical fiber bundle for transmitting an image of an object and a cylindrical light-focusing heterogeneous medium arranged near the end face of said optical fiber bundle on the object side and having refractive index distribution n given by the following formula:
- n = n.sub.0 (1 - 1/2 .alpha. R.sup.2)
- wherein reference symbol n.sub.0 represents refractive index on the optical axis, reference symbol .alpha. represents the coefficient of refractive index distribution and reference symbol R represents the distance from the optical axis, said optical system further comprising a negative lens arranged on the object side of said light-focusing heterogeneous medium.
Dependencies are inferred from the claim text.