Title:
PROJECTION LENS AND VIDEO PROJECTOR AND MULTI-VISION SYSTEM USING IT
Document Type and Number:
Japanese Patent JP3508011
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a compact projection lens whose back focus is long, whose whole length is short, which is provided with telecentric property and whose chromatic difference of magnification and distortion aberration are corrected.
SOLUTION: This projection lens 10 is constituted of a 1st negative-power group lens 1, a 2nd positive-power group lens 2, a 3rd negative-power group lens 3 and a 4th positive-power group lens 4. Then, the 2nd, the 3rd and the 4th groups are respectively constituted of at least two or more lenses. When the focal distance of the whole system of the projection lens is defined as f0, that of the 1st group lens is defined as f1g, that of the 2nd group lens is defined f2g, that of the 3rd group lens is defined as f3g, that of the 4th group lens is defined as f4g and a distance between the back end of the final lens and an image surface is defined as (bf) in the case that space between them is totally air, the expressions of 0.9≤f4g/bf≤1.1, -0.8≤f1g/f0≤-0.5, 0.5≤f2g/f0≤0.6 and -0.7≤f3g/f0≤-0.5 are obtained.
Inventors:
Kimura, Shunsuke
Takahashi, Masayuki
Takahashi, Masayuki
Application Number:
JP19031498A
Publication Date:
March 22, 2004
Filing Date:
July 06, 1998
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
G02B13/18; G02B9/62; G02B13/24; G09F9/00; H04N5/74; H04N9/31; (IPC1-7): G02B13/24; G02B9/62; G02B13/18
Attorney, Agent or Firm:
岡田 和秀
Previous Patent: SEMICONDUCTOR LIGHT EMITTING ELEMENT AND MANUFACTURE THEREOF
Next Patent: LIQUID CRYSTAL DISPLAY PANEL SCANNING LINE DRIVER
Next Patent: LIQUID CRYSTAL DISPLAY PANEL SCANNING LINE DRIVER