Patent · US Expired

Optical system for endoscopes

US4988172A · kind A · utility

15Cited by

1References

13Claims

0Family size

Assignee

Olympus Optical Co., Ltd. · JP

Inventors

Iwao Kanamori · Tokyo, JP
Akira Kikuchi
Minoru Okabe · Moriyama, JP

Key dates

Filing date	Jan 30, 1989
Grant date	Jan 29, 1991
Priority date	—
Expiry date	Jan 30, 2009

Classification

Technology area (CPC G)Physics
CPC primaryG02B23/2446
WIPO fieldOptics
WIPO sectorInstruments

Abstract

An optical system for endoscopes is provided with an inhomogeneous lens configured, as a relay lens, so that refractive index reduces progressively in going from a center portion toward a periphery and at least one of an entrance end face and an exit end face satisfies the following condition: EQU 0.15 P<C<0.35 P where P is the pitch of the inhomogeneous lens and C is distance from the entrance end face or the exit end face of the inhomogeneous lens to the imaging position closest to the end face in the lens. The optical system for endoscopes is low in manufacturing cost and allows a favorable image of an object to be observed in a clear field of view without being adversely affected by dirt and burr.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.