Rca Licensing Corporation

Rca Thomson Licensing Corp.

David Sarnoff Research Center, Inc.

Michael D Grote

Jeffrey Paul Johnson

Dennis John Bechis

A monochrome cathode ray tube (CRT) yoke includes harmonic windings for correcting spot distortion. In a first embodiment of the invention, the yoke includes harmonic windings in the entrance region of the yoke and harmonic windings in the exit region of the yoke. The harmonic windings in the entrance region produce a barrel-shaped field for correcting spot astigmatism along the diagonals of the CRT. The harmonic windings in the exit region of the yoke produce a pincushion-shaped field for correcting spot elongation along the diagonals of the CRT. In a second embodiment of the invention, the yoke includes harmonic windings only in the entrance region. A stigmator includes quadrupole coils driven at low power vertical scan rates. This allows the stigmator to be positioned near the electron gun and reduces the length of the CRT. In a third embodiment of the invention, the yoke includes harmonic windings only in the exit region.

Apparatus for correcting distortion of an electron beam generated spot

A deflection apparatus produces a field gradient that reduces a tendency of a major axis of a beam spot to become elongated at each corner, at each end of a horizontal axis and at each end of a vertical axis of a display screen relative to the beam spot at the center of the display screen. A beam spot stigmator causes the beam spot to be substantially anastigmatic at each of the corners, the end of the horizontal axis and the end of the vertical axis of the display screen.

Deflection system with a controlled beam spot

A deflection apparatus includes a pair of quadrupole arrangements for producing a pair of quadrupole fields in a beam path of an electron beam at different distances from a display screen. In an embodiment of the invention, the first and second quadrupole arrangements and a main deflection field producing arrangement cooperate to converge three electron beams, R, G and B, with one another.

Deflection system with a pair of quadrupole arrangements

An assembly that includes four separate tabs is used for producing from a stray magnetic field flux, a pincushion shaped field in a portion of the neck of a cathode ray tube that is located at the rear of a deflection yoke for providing vertical convergence coma correction. Coils that are wound around the tabs form a quadrupole electromagnet that also provides dynamic convergence correction.

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Mercerville, NJ, United States of America

Michael D Grote