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:
Jul. 28, 1992
Filed:
Mar. 19, 1990
Tsutomu Muraji, Nara, JP;
Yoshito Miyatake, Neyagawa, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A projection type image display apparatus uses an optical modulation image display device as a light valve. Notwithstanding the use of a metal vapor discharge lamp which has a long re-starting period of time as a light source, the apparatus can display images instantaneously by igniting the discharge lamp for a prescribed period of time after switching off and then on again a main power source of the apparatus. Also, the projection type image display apparatus does not generate audio noise at the time of starting the discharge lamp. Furthermore, even in case of adding an instantaneous re-ignition circuit, the frequency of use of such instantaneous re-ignition circuit can be suppressed to an utmost extent, and the useless igniting period of time of the discharge lamp can be curtailed.