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:
Oct. 31, 2000
Filed:
Jul. 21, 1999
Hideaki Shimonura, Kawasaki, JP;
Yuji Manabe, Kamakura, JP;
Tetsuo Hattori, Yokohama, JP;
Masaaki Kusano, Kawasaki, JP;
Atsushi Sekine, Kasukabe, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Apparatus are disclosed that provide a high-luminance projected image with no color shading or uneven contrast. Light from a light source undergoes color separation by passing through a color-separation optical system (e.g., a cross-dichroic mirror or cross-dichroic prism). The light from the light source can also be split into first and second polarized lights by passage through, e.g., a first polarized-light beamsplitter (PBS). Each color-separated light is modulated by a respective color-signal light valve and undergoes color combining by, e.g., a cross-dichroic prism. The second polarized light, if formed, is modulated by a luminance-signal light valve, undergoes color combining and polarized-light combining by, e.g., a second PBS, and is projected by a projection lens (that comprises an aperture stop). The PBSs, cross-dichroic mirrors, and cross-dichroic prisms are situated where principal rays (defined by the aperture stop) are parallel to the optical axis. The first PBS (if present) and color-separation optical system are preferably arranged between a front illumination lens group and a rear illumination lens group both comprising an illumination relay optical system telecentric on both front and rear sides thereof. Field lenses and relay lenses can be included that comprise a relay optical system forming a magnified image of the color-signal light valves at a position conjugate to the luminance-signal light valve with respect to the projection lens.