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:
Apr. 03, 1984
Filed:
Apr. 18, 1980
Jan Gerritsen, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A device for and methods of measuring and adjusting the convergence of the electron beams in a color display tube of the shadow mask type. The device includes a detector in the form of a divided photosensitive cell comprising at least two separate photosensitive surface parts which are situated symmetrically relative to the center of the cell. The photosensitivity of the surface parts increases substantially from the center of the cell. In use the device is mounted so that the detector is on the central area of the display screen. Three lines are produced in one deflection direction of the tube by means of the three electron beams with one video signal. The central line and detector are moved relative to each other until the longitudinal axis of the line coincides with the center of the cell. Then either the distances from the axes of the other two lines to the axis of the center line are measured by determining the differences of the incident light impinging on the two separate surface parts and the measurements are stored for subsequent use or the static convergence unit of the tube is adjusted until all three lines coincide. The method is repeated for three lines extending in the other deflection direction.