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:
May. 29, 2001
Filed:
Feb. 17, 1998
Christaan Hentschel, Eindhoven, NL;
Leendert Vriens, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A display monitor operating under the raster scanning system repeats the line scanning of an electron beam by moving the resulting scanning lines in a direction substantially perpendicular to the line direction. In a cathode ray tube (CRT), the dot pitch of the fluorescent material on the display screen (DS) of the cathode ray tube (CRT) that can emit a fluorescence is determined by the aperture pitch of the shadow mask. Thus, in case of displaying a video pattern (f1h) in which consecutive pixels in a line repeat in an ON and OFF sequence an interference with the aperture pitch of the shadow mask may occur, thereby causing a moiré. The moiré phenomenon is reduced with a notch filter (NF) which has a passband for baseband video frequencies (f1h) and which has a notch in the amplitude characteristic at a spatial frequency a) at or near to a spatial frequency of dots (fdh or fhh) on the display screen (DS), or b) at or near to a predetermined spatial higher harmonic (f2h, f4h) of the baseband video (f1h) which is near to said spatial frequency of the dots (fdh or fhh).