Cathode-ray tube apparatus
AssigneeMatsushita Toshiba Picture Display Co., Ltd.
InventorKatsuyo Iwasaki
Life of this patent
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Abstract
A pair of coma coils for correcting a VCR that is a positional displacement in a vertical axis direction of a center electron beam with respect to the center of a pair of side electron beams on a vertical axis in upper and lower portions on a screen are provided at a position in the vicinity of an end of a deflection yoke on an electron gun side. Assuming that a maximum value of the intensity of a vertical deflection magnetic field on a tube axis is HMAX, and the intensity of a vertical deflection magnetic field on the tube axis at the position where the pair of coma coils are arranged in the tube axis direction is HC, HC/HMAX≧0.8 is satisfied. Owing to this, high-order distortion of horizontal lines on a screen can be corrected.
Claims4
A cathode-ray tube apparatus, comprising:
- a panel with a substantially rectangular phosphor screen formed on an inner surface;
- a funnel connected to the panel;
- an electron gun housed in a neck of the funnel and emitting a center electron beam and a pair of side electron beams on both sides of the center electron beam;
- a deflection yoke mounted on an outer circumference of the funnel;
- and a pair of coma coils placed at a position in a vicinity of an end of the deflection yoke on the electron gun side and correcting a VCR that is a positional displacement in a vertical axis direction of the center electron beam with respect to a center of the pair of side electron beams on a vertical axis in upper and lower portions of a screen,
- wherein assuming that a maximum value of intensity of a vertical deflection magnetic field on a tube axis is HMAX, and intensity of the vertical deflection magnetic field on the tube axis at the position where the pair of coma coils are placed in a tube axis direction is HC, HC/HMAX≧0.8 is satisfied.
Dependencies are inferred from the claim text.