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:
Mar. 21, 1995
Filed:
Dec. 21, 1993
Applicant:
Inventor:
Wilhelmus A Timmers, Eindhoven, NL;
Assignee:
U.S. Philips Corporation, New York, NY (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
353101 ; 348745 ;
Abstract
An image projection device comprising at least one display panel (26, 27, 28), a projection lens system (C) and a focus error detection system (FS) is described. Since the radiation source (50) and the radiation-sensitive detector (51) of the focus error detection system are arranged in planes which effectively coincide with the plane of the display panel (28), and a focus measuring beam b traverses the projection lens system twice on its path to and from a projection screen (D), an accurate and reliable focus error signal (S.sub.f) is obtained.