Title:
IMAGING LENS
Document Type and Number:
WIPO Patent Application WO/2004/038478
Kind Code:
A1
Abstract:
An imaging lens (100) comprising, arranged sequentially from the object side, a positive-meniscus first lens (1) with its convex plane facing the object side, a negative-power-meniscus second lens (2), and a positive-power third lens (3), the second and third lenses (2, 3) functioning as correction lenses. The first lens (1) has a strong power, and both the second and third lenses (2, 3) are aspherical on opposite planes. When the synthetic focal distance of the imaging lens is f, the focal distance of the first lens f1, the distance from the incident surface on the object side to the imaging surface of the first lens (1) Σd, and the Abbe number of the second lens νd2, the following conditional expressions are satisfied. 0.50 < f1/f < 1.5 (1) 0.50 <∑d/f < 1.5 (2) 50 > νd2 (3) Accordingly, a small, low-cost imaging lens capable of high-quality imaging can be realized.
Inventors:
KUBOTA YOJI (JP)
MATSUI TOSHIO (JP)
MATSUI TOSHIO (JP)
Application Number:
PCT/JP2003/013504
Publication Date:
May 06, 2004
Filing Date:
October 22, 2003
Export Citation:
Assignee:
NAGANO OPTICS LAB CORP (JP)
KUBOTA YOJI (JP)
MATSUI TOSHIO (JP)
KUBOTA YOJI (JP)
MATSUI TOSHIO (JP)
International Classes:
G02B9/16; G02B13/00; G02B13/18; (IPC1-7): G02B13/00; G02B13/18
Foreign References:
| US6441971B2 | 2002-08-27 | |||
| JPS62109014A | 1987-05-20 | |||
| US6028711A | 2000-02-22 | |||
| JP2002228922A | 2002-08-14 | |||
| JPH04211214A | 1992-08-03 | |||
| JPH1152227A | 1999-02-26 | |||
| US5940219A | 1999-08-17 |
Attorney, Agent or Firm:
Yokozawa, Shiro (Shimadachi Matsumoto-shi, Nagano, JP)
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