Title:
内視鏡用対物レンズおよび内視鏡
Document Type and Number:
Japanese Patent JP6401103
Kind Code:
B2
Abstract:
An objective lens for endoscopes includes, in order from the object side: a front group; an aperture stop; and a positive rear group. The front group includes, in order from the object side, a negative first lens, in which the absolute value of the radius of curvature of the surface toward the image side is less than that of the surface toward the object side, and at least one plane parallel plate. The rear group includes, in order from the object side, a positive second lens, and a cemented lens formed by a positive third lens and a negative fourth lens. The coupling surface of the cemented lens is convex toward the image side. Conditional Formulae (1) through (3) concerning the plane parallel plates within the front group, the focal length of the first lens, the radius of curvature of the coupling surface of the cemented lens, etc., are satisfied.
Inventors:
Keisuke Harada
Rinsei Cho
Rinsei Cho
Application Number:
JP2015085867A
Publication Date:
October 03, 2018
Filing Date:
April 20, 2015
Export Citation:
Assignee:
FUJIFILM Corporation
International Classes:
G02B13/04; A61B1/00; G02B13/18; G02B23/26
Domestic Patent References:
| JP51062053A | ||||
| JP51044937A | ||||
| JP2006003549A | ||||
| JP2002057921A | ||||
| JP9138342A |
Foreign References:
| US20090290236 | ||||
| WO2016132613A1 |
Attorney, Agent or Firm:
Patent Service Corporation Taiyo International Patent Office