The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 23, 2008

Filed:

Oct. 26, 2005
Applicants:

Takanori Hisada, Yokohama, JP;

Hiroki Yoshikawa, Hiratsuka, JP;

Tetsu Ohishi, Hiratsuka, JP;

Masahiko Yatsu, Fujisawa, JP;

Koji Hirata, Yokohama, JP;

Inventors:

Takanori Hisada, Yokohama, JP;

Hiroki Yoshikawa, Hiratsuka, JP;

Tetsu Ohishi, Hiratsuka, JP;

Masahiko Yatsu, Fujisawa, JP;

Koji Hirata, Yokohama, JP;

Assignee:

Hitachi, Ltd., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B 21/22 (2006.01);
U.S. Cl.
CPC ...
Abstract

In the image display device, a projection lens including a plurality of lenses for enlarging an image from an image display element is constituted of a front group and a rear group. The rear group includes at least one free-shaped-surface lens including a surface having a rotationally asymmetrical shape. Furthermore, the device includes at least one free-shaped-surface mirror having a rotationally asymmetrical reflection surface. Accordingly, a set can be formed to be compact while correcting trapezoidal distortion and aberration.


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