Title:
【発明の名称】大口径広角レンズ
Document Type and Number:
Japanese Patent JP2596800
Kind Code:
B2
Abstract:
PURPOSE:To compensate a chromatic aberration by providing a 2nd lens group with a distributed index lens which satisfies a specific condition. CONSTITUTION:The large-diameter wide-angle lens consists of a 1st lens group 1 which has negative refracting power, the 2nd lens group II which has positive refracting power, a stop r11, and 3rd lens group III which has positive refracting power in order from an object side and the 2nd lens group II is provided with the distributed index lens which has a refractive index gradient axially to satisfy the condition shown by an inequality I. In the inequality I, rF is the radius of curvature of the body side surface of the distributed index lens, rR is the radius of curvature of the image- side surface of the distributed index lens, fG is the focal length of the distributed index lens, and (f) is the focal length of the whole system. Here, the diameter of an axial type distributed index lens is easy to increase and given variation in refractive index gradient by wavelength. Consequently, the chromatic aberration which can not be compensated by an aspherical surface can be compensated.
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Inventors:
Norihiko Aoki
Application Number:
JP17173788A
Publication Date:
April 02, 1997
Filing Date:
July 12, 1988
Export Citation:
Assignee:
Olympus Optical Co., Ltd.
International Classes:
G02B9/00; G02B13/04; (IPC1-7): G02B13/04; G02B9/00
Domestic Patent References:
| JP62177515A |
Attorney, Agent or Firm:
Koji Mukai