Title:
LENS DEVICE
Document Type and Number:
WIPO Patent Application WO/2004/010196
Kind Code:
A1
Abstract:
A lens device comprising, arranged sequentially from a subject side, a meniscus first lens (1) convexed toward the subject side, a second lens (2) facing the concave of the first lens (1), a negative third lens (3) having a concave facing the second lens (2), and a positive fourth lens (4) having a convex rear plane, wherein when ν3 is the Abbe number of the third lens (3), ν4 the Abbe number of the fourth lens, Ymax a maximum image height, f a synthesized focal distance, and ∑d a distance from the first plane on the subject side of the first lens (1) up to the second plane on an imaging plane side of the fourth lens (4), the conditions (1) ν3 <ν4, (2) 0.5 < Ymax/f < 0.8, (3) ∑d < 1.5f are satisfied, and at least one plane of the first lens (1) and the fourth lens (4) has an aspherical shape.
Inventors:
NIO JUNICHI (JP)
YOSHIDA HISATSUGU (JP)
OGINO SHUJI (JP)
YOSHIDA HISATSUGU (JP)
OGINO SHUJI (JP)
Application Number:
PCT/JP2003/009016
Publication Date:
January 29, 2004
Filing Date:
July 16, 2003
Export Citation:
Assignee:
SEIKO PRECISION KK (JP)
NIO JUNICHI (JP)
YOSHIDA HISATSUGU (JP)
OGINO SHUJI (JP)
NIO JUNICHI (JP)
YOSHIDA HISATSUGU (JP)
OGINO SHUJI (JP)
International Classes:
G02B9/34; G02B13/18; G02B13/00; G02B15/173; (IPC1-7): G02B13/00
Foreign References:
| US5822132A | 1998-10-13 | |||
| JPH05210047A | 1993-08-20 | |||
| JPH1130745A | 1999-02-02 | |||
| JPH01183619A | 1989-07-21 |
Attorney, Agent or Firm:
Katayama, Shuhei (6-1 Kyobashi 1-chom, Chuo-ku Tokyo, JP)
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