Mitsubishi Denki Kabushiki Kaisha

Nitto-denko Corporation

Tatsuhiro Hirakawa

Hidenori Takita

Seiichi Takaoka

Shinji Nohara

Masatoshi Ochiai

A color cathode ray tube display device comprises a color cathode ray tube including a neck portion (1a), a funnel portion (1b), and a panel portion (1c), a compensating coil (7) which generates a compensating magnetic field for eliminating the influence of an external magnetic field that acts vertically on electron beams which will intersect a display screen of the color cathode ray tube (1), a current supply unit (4,5) for passing a sawtooth current synchronized with the vertical deflection cycle of a video signal into the compensating coil (7) so that the compensating coil generates the compensating magnetic field, and a memory (5b) for storing information about the sawtooth current passing through the compensating coil (7).

Color cathode ray tube display device and method of eliminating the

A cathode-ray tube includes an envelope in which a panel portion, a funnel portion, and a neck portion are integrally formed, and a conductor film and a deflecting yoke mounted on an outer surface of the funnel portion. A strip-type electric field reducing piece has a coated portion coated with an insulator, and an exposed conductive material portion. The coated portion is disposed between the funnel portion and the deflecting yoke, and the conductive material portion is connected to the conductor film.

Cathode-ray tube and display unit using the cathode-ray tube

A color CRT display apparatus in which the polarity and the strength of the external magnetic field in the tube direction of a CRT are detected by a magnet detecting element, and a current corresponding to the strength of the external magnetic field is supplied to a compensating coil which is wound around a funnel portion between a display panel and a deflection yoke and at a place where a purity rotation and a raster rotation by said external magnetic field in said tube direction are simultaneously compensated, thereby both the purity rotation and the raster rotation can be automatically compensated in an optimum state.

Growing community of inventors

Tokyo, Japan

Tatsuhiro Hirakawa