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:
Jan. 31, 1995
Filed:
Apr. 24, 1992
Kentaro Oku, Mobara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A projection system for pictures and a projection display apparatus which are designed to improve the luminance and contrast of a magnified picture on a projection screen by increasing the luminous flux projected within the effective size of projection optical systems. The projection display apparatus has a picture compression device for compressing the aspect ratio of the source picture formed on the face plate panel (PNL) of a projection cathode-ray tube (PRT) or a liquid crystal panel (LCP) to make it substantially 1 and an optical system for extending a picture (EXT) for extending the source picture having the same aspect ratio as that of the original picture. With this construction, the whole luminous flux passing the effective size of the projection optical system is maximized with the effect of improving the luminance and contrast of the magnified pictured projected onto the projection screen.