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Patent Searching and Data


Title:
IMAGING LENS BY MEANS OF TWO LENSES
Document Type and Number:
Japanese Patent JPH07168092
Kind Code:
A
Abstract:

PURPOSE: To realize an imaging lens by means of two lenses, which is long in a back focus, able to take a field angle relatively wider, bright and compact in size, in addition to making cost-down promotable by regulating the extent of value of a ratio between the center thickness of a lens at the subject side, consisting of a meniscus lens and the focal distance of a lens system as a whole, aside from two-lens constitution.

CONSTITUTION: This lens, consisting of two lenses L1 and L2, is made up of installing a stop (i) in space between the second lens L2 and a low-pass filter 2, and in this constitution, a beam of light incident along an optical axis X from the body side is imaged in an image-formation position P of a solid camera element 1. Here the first lens L1 is a meniscus lens being weak in refractive power directing a concave to the side of a subject and the second lens L2 is of lens with positive refractive power, and both lenses L1 and L2 are made of glass. In addition, these lenses satisfies a conditional expression of 0.19≤d1/f≤1.7. In this connection, d1 in this expression means center thickness of the first lens.


Inventors:
YAMADA HIROSHI
Application Number:
JP31464993A
Publication Date:
July 04, 1995
Filing Date:
December 15, 1993
Export Citation:
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Assignee:
FUJI PHOTO OPTICAL CO LTD
International Classes:
G02B9/04; G02B9/10; G02B13/00; (IPC1-7): G02B9/10
Attorney, Agent or Firm:
Seiji Yanagida (1 person outside)