Kabushiki Kaisha Toshiba

Nobuhiko Akoh

Masatsugu Inoue

Norio Shimizu

Kumio Fukuda

Tohru Takahashi

Takashi Murai

Shinichiro Nakagawa

Takuya Mashimo

Tadahiro Kojima

Yoshiaki Ito

Tadashi Ite

A deflection yoke of a cathode ray tube apparatus comprises a pair of saddle-type horizontal deflection coils located symmetrically with respect to a central axis and substantially in the shape of a truncated pyramid. A magnetic core substantially in the shape of a truncated cone is located coaxially around the horizontal deflection coils, and a pair of vertical deflection coils are wound on the magnetic core. A relation between a space vf between a large-diameter end portion of the magnetic core and each of the horizontal deflection coils and a space vr between a small-diameter end portion of the magnetic core and each of the horizontal deflection coils, with respect to the direction of a vertical axis perpendicular to the central axis, is given by vf&gE;vr.

Deflection yoke and cathode ray tube apparatus provided with the same

A shadow mask of a color cathode-ray tube has a substantially rectangular mask main body and a substantially rectangular mask frame fixed to a skirt portion of the mask main body. The mask main body has a curved effective surface formed with a large number of electron-beam passage apertures and opposing the phosphor screen, a non-aperture portion surrounding the outer periphery of this effective surface, and a skirt portion formed in a bent on the outer periphery of the non-aperture portion. The mask main body has a long axis extending in a horizontal direction and crossing with a tube axis, and a short axis extending in a vertical direction and crossing with both the tube axis and the long axis. The effective surface and the non-aperture portion of the mask main body are formed in a curved surface having a radius of curvature in the short axis direction. At each long side of the mask main body, each end portion of the short axis of the effective surface and the non-aperture portion is recessed from any other adjacent part, in a direction leaving from the phosphor screen along the tube axis. The radius of curvature in a short axis direction near the short axis of the effective surface and the non-aperture portion of the mask main body is smaller than the radius of curvature in the short axis direction at other parts.

Color cathode ray tube with curved shadow mask having central recessed portions

A color cathode ray tube has a shadow mask. The shadow mask is composed of an almost rectangular mask body and an almost rectangular mask frame. The mask body has an effective surface facing a fluorescent screen, a non-aperture section surrounding the effective surface, and a bent skirt section formed on the periphery of the non-aperture section. The mask frame has a sidewall section provided on the skirt section of the mask body. In the shadow mask of such a configuration, a step section having a step in the direction perpendicular to the skirt section of the mask body is formed. With this configuration, the strength with which the curved surface of the effective surface of the shadow mask is enhanced, which prevents the color purity from deteriorating due to deformation and facilitates the formation of the shadow mask.

Color cathode ray tube having a shadow mask of improved strength

A color cathode ray tube has a substantially rectangular shadow mask in which a plurality of slit type aperture arrays are aligned in the direction of the major axis of an effective region defined by a curved surface opposing a phosphor screen formed on the inner surface, defined by a concave curved surface, of the effective region of a panel. Each slit type aperture array is obtained by arranging a plurality of slit type apertures in an array in the direction of the minor axis of the effective region of the shadow mask. In this color cathode ray tube, the difference between the array interval of the slit type aperture arrays at a peripheral portion on the long side of the shadow mask and the array interval of the slit type aperture arrays on the major axis is a maximum value within a distance range of 0.4 h to 0.9 h (h is 1/2 the length of the effective region of the shadow mask in the direction of the major axis) from the minor axis, and the array interval of the slit type aperture arrays at the end of the major axis is larger than that of the slit type aperture arrays at a corner. Thus, local doming of the shadow mask can be suppressed.

Color cathode ray tube with suppressed doming

A deflection device for use in a color cathode-ray tube, which has a pair of horizontal deflection coils for generating a pincushion-shaped horizontal deflection magnetic field, a pair of vertical deflection coils for generating a barrel-shaped vertical deflection magnetic field. The deflection device also having a pair of correction coils each of which being located at a distance of 10 mm or less from a plane containing the center and vertical axes of the device, a current flowing through each correction coil in synchronism with, and in a direction opposite to, the currents flowing in the horizontal deflection coils. The deflection device may also include a second pair of correcting coils, each of which being located adjacent to the first pair of correcting coils and arranged in a similar arrangement relative to the plane defined by the center and vertical axes.

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Nitta-gun, Japan

Nobuhiko Akoh