Matsushita Toshiba Picture Display Co., Ltd.

Akira Satou

Katsuyo Iwasaki

Kenichiro Taniwa

Koji Nishiyama

Hiroji Morimoto

A plurality of magnet rings for correcting a convergence are arranged in a tube axis direction with spacers interposed therebetween, on an outer circumferential surface of a neck. A velocity modulation coil for modulating a scanning velocity in a horizontal direction of an electron beam is placed so that a position of the velocity modulation coil in the tube axis direction is overlapped with those of the magnet rings. At least one of the spacers is made of only a magnetic substance. Alternatively, at least one of the spacers is made of a magnetic substance, and the outermost surface in a radius direction of the spacer made of a magnetic substance is covered with a non-metallic material. Because of this, the magnetic field formed by the velocity modulation coil can be intensified without disturbing the magnetic field of the magnet rings of a CPU.

Cathode-ray tube apparatus with magnetic spacers between magnetic rings

A pair of velocity modulation coils are placed with a horizontal plane including a tube axis interposed therebetween, and a pair of magnetic substances are placed with a vertical plane including a tube axis interposed therebetween. A straight line portion of the velocity modulation coil extending substantially in parallel to the tube axis is placed between the magnetic substance and the tube axis. An interval D between the magnetic substance and the straight line portion is 1 to 3 mm. Assuming that the tube axis is a Z-axis, a size of the velocity modulation coil in a tube axis direction is L, and a position of an end of the velocity modulation coil on a side opposite to a phosphor screen in the tube axis direction is Z=0, a center point of the pair of magnetic substances in the tube axis direction is present in a range of Z=0.2&#xd7;L to 0.9&#xd7;L. Consequently, the sensitivity of velocity modulation can be enhanced while suppressing an increase in a driving power with a simple configuration.

Velocity modulation coil apparatus and cathode-ray tube apparatus

A deflection coil for deflecting an electron beam emitted from an electron gun is provided outside a cathode-ray tube in which the electron gun is housed, and a phosphor screen is formed. The cathode-ray tube further includes a velocity modulation coil for modulating a horizontal scanning velocity of an electron beam, a first magnetic substance surrounding an outer circumference of the cathode-ray tube from outside the velocity modulation coil, and a second magnetic substance surrounding the outer circumference of the cathode-ray tube between the deflection coil and the first magnetic substance. Because of this, the sensitivity of velocity modulation can be enhanced effectively with a simple configuration while deflection distortion is prevented.

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Ibaraki, Japan

Akira Satou