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. 01, 1997
Filed:
Mar. 22, 1995
David Leaver, Sussex, GB;
International Business Machines Corporation, Armonk, NY (US);
Abstract
Cathode ray tube display apparatus includes a cathode ray tube having a screen (210) and a neck (350). In use an electron beam is directed from the neck (350) towards the screen (210) along an axis (S) of the cathode ray tube containing the centre of the screen (210). However, deflection means (320) mounted on the neck (350) deflects the beam from the axis (S) at a deflection centre (X) of the cathode ray tube to scan the beam across the screen (210) in a raster pattern. Raster rotation means (300, 310) permits rotation of the raster pattern about the centre of the screen (210). The raster rotation means (300, 310) includes first and second coils. The first coil (300) is located around the neck (350) at or near the deflection centre (X) to generate, in use, a first magnetic field in the path of the electron beam. The second coil (310) is parallel to the first coil (300) and located around the neck (350) on the side of the deflection centre (X) remote from the screen (210) to generate, in use, a second magnetic field, of opposite polarity to the first field, in the path of the electron beam.