Matsushita Electric Industrial Co., Ltd.

Matsushita Toshiba Picture Display Co., Ltd.

Hideaki Etou

Kenichiro Taniwa

Hideharu Ohmae

Nozomu Arimoto

Yoshikazu Demi

Atsushi Kato

In a cross-section including a tube axis, assuming that Trepresents a thickness of a funnel at a point on an outer circumferential surface of the funnel, which is placed at the same position in a tube axis direction as that of an end of a horizontal deflection coil on a phosphor screen side, and Trepresents a thickness of the funnel at a point on the outer circumferential surface of the funnel, which is placed at the same position in the tube axis direction as a position 7 mm away from the end of the horizontal deflection coil on the phosphor screen side to the phosphor screen side along the tube axis, the funnel includes at least one cross-section including the tube axis satisfying a relationship: T/T&#x2267;1.18. Owing to this, cone halation can be prevented while an X-ray leakage amount is limited to a predetermined value or less.

Cathode-ray tube apparatus

Each of a plurality of arrays of apertures of a shadow mask has a vertically long aperture, a vertically short aperture and a bridge between these apertures. In each of the arrays of apertures, one long aperture and one or more short apertures are arranged alternately, and a horizontal maximum width Hof the short aperture is larger than a horizontal basic width Hof the long aperture. This makes it possible to provide a color cathode ray tube having an improved brightness without causing moir&#xe9; fringes, color displacement, breaking of the shadow mask or variation in color purity.

Color cathode ray tube having variable apertures in a shadow mask

A color picture tube includes: a glass panel having a substantially rectangular-frame skirt; a rectangular frame holding a shadow mask; and a support spring elastically supporting the frame inside the skirt and fixed to a first position at inside surface of a long side of the skirt and to a second position at the facing outside surface of the frame. The first and second positions are away in horizontal axis direction perpendicular to tube axis and substantially parallel to the long side. The second position is more away from vertical axis perpendicular to tube axis and horizontal axis than the first position. Materials for the support spring and frame are selected so that, in horizontal axis direction, thermal expansion amount of the support spring between the first and second positions is substantially same as that of the frame between the second position and vertical axis when the tube is operated.

Color picture tube

In a color picture tube, a phosphor screen is formed on an inner face of a face panel, which is formed of a plurality of phosphor lines in the form of stripes, and a color selecting electrode opposed to the phosphor screen is provided. The color selecting electrode has a plurality of apertures and bridges each separating the adjacent apertures from each other in a direction along the phosphor lines. In the vicinities of shadows of the bridges formed as a result of projection by electron beams, each of light emitting regions in which the phosphor lines emit light by irradiation with the electron beams has a part in which a wide portion of a greater width than a basic width Wb of the light emitting region is provided. Darkening of the phosphor screen can be compensated, which is caused by the shadows of the bridges shading the phosphor lines. Thus, a decrease in the luminance of the phosphor screen and picture noise that are caused by the shadows of the bridges can be suppressed.

A cathode ray tube capable of reducing the doming amount and suppressing the occurrence of moire stripes at the same time, which also can prevent the so-called persimmon stone phenomenon from occurring, is provided. In the apertures, the protruding portions that are protruding from end faces in the horizontal direction of the apertures to the inside of the apertures are formed. The protruding portion in the aperture located on the right side of the phosphor surface from the vertical center line of the shadow mask is protruding in the direction toward the peripheral portion on the right side, while the protruding portion in the aperture located on the left side of the phosphor surface is protruding toward the peripheral portion on the left side. Accordingly, the doming amount can be reduced and the occurrence of moire stripes can be suppressed at the same time, while the persimmon stone phenomenon in which the beam spot of an electron beam on the phosphor surface is cut partially can be prevented from occurring.

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Hirakata, Japan

Hideaki Etou