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Title:
【発明の名称】写真用広角レンズ
Document Type and Number:
Japanese Patent JP2879458
Kind Code:
B2
Abstract:
PURPOSE:To compensate an image plane characteristic and a spherical aberration excellently and to maintain excellent picture quality at the peripheral par and the center part of a picture plane by limiting the radii of curvature of the object-side surface and image-plane-side surface of a lens within specific ranges. CONSTITUTION:The object-side surface of a positive meniscus lens L which is convex to the object side is made aspherical increasing in surface curvature with the distance from the optical axis and the surface of the meniscus lens L on the image formation side is made aspherical differently in surface curvature from the object-side surface. Then an inequality l holds, where r1 is the paraxial radius of the surface of the lens on the object side, r2 is the paraxial radius of the surface of of the lens on the image-formation-plane side, (n) is the refractive index of the lens to reference wavelength, (f) is the focal length of the lens to the reference wavelength. Consequently, the image plane characteristic is compensated excellently ad deterioration in spherical aberration can be compensated.

Inventors:
OONO KAZUNORI
Application Number:
JP5631290A
Publication Date:
April 05, 1999
Filing Date:
March 09, 1990
Export Citation:
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Assignee:
FUJI SHASHIN KOKI KK
International Classes:
G02B9/02; G02B13/04; G02B13/18; (IPC1-7): G02B13/04; G02B13/18
Domestic Patent References:
JP63246713A
JP2106710A
Attorney, Agent or Firm:
Michio Oshima