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Patent Searching and Data


Title:
PHOTOGRAPHIC LENS
Document Type and Number:
Japanese Patent JPH0990213
Kind Code:
A
Abstract:

To lower the price and secure sufficient performance although the lens system consists of five elements.

The photographic lens consists 5-element constitution formed of a concave lens 1 made of glass, a lens 2 made of plastic, a convex lens 3 made of glass, a concave lens 4 made of glass, and a convex lens 5 in order of an object side; and the 2nd plastic lens 2 is composed of a powerless meniscus lens and its image-side surface is made aspherical. Therefore, the influence of environmental changes of temperature, humidity, etc., is not exerted because of the 2nd powerless lens 2 and stable characteristics are obtained; and the aspherical surface of this 2nd lens 2 compensates a large spherical aberration and a comatic aberration generated by the image-side surface of the 3rd convex lens 3 to reduce the load of aberration compensation on the glass-made lenses which are formed in easy-to-process shapes to greatly lower the cost inspite of the 5-element lens constitution.


Inventors:
KIKUCHI MASAHITO
Application Number:
JP26472395A
Publication Date:
April 04, 1997
Filing Date:
September 20, 1995
Export Citation:
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Assignee:
CASIO COMPUTER CO LTD
International Classes:
G02B9/60; G02B13/18; (IPC1-7): G02B9/60; G02B13/18
Attorney, Agent or Firm:
Jiro Sugimura