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.
Patent No.:
Date of Patent:
Aug. 25, 1992
Filed:
Apr. 09, 1991
Shinsuke Shikama, Nagaokakyo, JP;
Masahiro Usui, Nagaokakyo, JP;
Eiichi Toide, Nagaokakyo, JP;
Hiroshi Kida, Nagaokakyo, JP;
Mitsushige Kondo, Nagaokakyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The projection-type display device has a light source emitting a parallel luminous flux, a liquid crystal light valve disposed on the luminous flux and outputs a rectangular two-dimensional image to be projected on a screen, and a projection lens magnifying the rectangular two-dimensional image output. The light source has a first concave mirror (parabolic mirror) the reflective surface of which is oriented in the direction of emission of the luminous flux, a lamp laced in front of the first concave mirror, and a second concave mirror (parabolic mirror or spherical mirror), the reflective surface of which is oriented toward the first concave mirror. In the second concave mirror is formed an aperture window, which is a rectangle of substantially similar to that of the liquid crystal light valve and emits a rectangular luminous flux. The beam from the lamp is reflected by the first concave mirror, and one or more times by the second concave mirror, becoming a parallel beam oriented in the direction of the optical axis. The parallel light beam is made into a luminous flux of rectangular cross section by the rectangular aperture window. Accordingly, luminous flux is not blocked wastefully, but serves to increase the brightness of the projected image.