Title:
超広角レンズ系
Document Type and Number:
Japanese Patent JP4481714
Kind Code:
B2
Abstract:
A wide-angle lens system includes a negative first lens group, a negative second lens group, and a positive third lens group. The negative first lens group includes at least two negative meniscus lens elements each having the convex surface facing toward the object, and a positive lens element provided on the image-side of the two negative meniscus lens elements. The negative second lens group includes cemented lens elements and a negative meniscus lens element having the convex surface facing toward the object. The wide-angle lens system satisfies the following conditions: f2-3/f>1.6 (1) f3/f>1.5 (2) (f2-3/f)/(f3/f)>1.0 (3) wherein f2-3 designates the combined focal length of the negative second lens group and the positive third lens group; f designates the focal length of the entire wide-angle lens system; and f3 designates the focal length of the positive third lens group.
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Inventors:
Jun Hirakawa
Application Number:
JP2004131996A
Publication Date:
June 16, 2010
Filing Date:
April 27, 2004
Export Citation:
Assignee:
HOYA CORPORATION
International Classes:
G02B13/04; G02B9/12; G02B13/06; G02B15/14; G02B15/177
Domestic Patent References:
| JP4829429A | ||||
| JP5043914A | ||||
| JP6175314A | ||||
| JP450910A | ||||
| JP4118612A | ||||
| JP4235515A | ||||
| JP7261082A | ||||
| JP886964A | ||||
| JP8171053A | ||||
| JP9113798A | ||||
| JP200343350A | ||||
| JP200412504A |
Attorney, Agent or Firm:
Kunio Miura