Kabushiki Kaisha Toshiba

Shinichiro Nakagawa

Masatsugu Inoue

Norio Shimizu

Takashi Murai

Takuya Mashimo

Yoshiaki Ito

Shinji Ohama

Kumio Fukuda

Nobuhiko Akoh

Takeshi Nakayama

Color cathode ray tube having a radius of curvature ratio relationship

A shadow mask includes a substantially rectangular effective region formed having a number of electron beam passage apertures and opposed to a phosphor screen and a substantially rectangular skirt portion provided around the effective region and extending in the direction of a tube axis. The skirt portion has a pair of long sides extending substantially parallel to a major axis and a pair of short sides extending substantially parallel to a minor axis, the long and short sides being welded to the inner surface of a substantially rectangular mask frame. A distance a from an extending end of the skirt portion on each long side to the weld spot is longer than a distance b from an extending end of the skirt portion on each short side to the weld spot.

Color cathode ray tube

A color picture tube includes a panel of which substantially rectangular effective area has a flat external surface and a curved internal surface, and on the internal surface of the effective area thereof a phosphor screen is formed. The internal surface of the effective area of the panel, when an average radius of curvature in major axis direction is RH, an average radius of curvature in minor axis direction is RV, an average radius of curvature in long side direction is RL and an average radius of curvature in short side direction is RS, is formed in a curved face satisfying RH>RV and RS&gE;RV, or RH>RV and RS&gE;RV and RL&gE;RH. In this color picture tube, flatness of the effective area of the panel and visibility are improved.

Color picture tube

A skirt portion of a mask body includes cut portions. The width of the cut portions along the minor or major axis ranges from 0.10&times;L to 0.45&times;L, where L is the distance from an end of the minor or major axis to a diagonal end, and the height of the cut portions along the tube axis is equal to 5% to 40% of the height of the skirt portion along the tube axis in a region near the minor or major axis.

Color cathode ray tube having color sorting mask including cut portions

In a color cathode ray tube in which the external surface of an effective portion of a panel has a flat surface or a slight curvature, the shadow mask is set such that the layout distance between electron beam through hole array near the long side of an effective surface of the shadow mask is larger in the vicinity of the short axis than the layout distance at the center of the effective surface. Further, the layout distance becomes gradually smaller in direction away from the short axis, and thereafter, the layout distance changes to an increase. In the vicinity of the short side of the effective surface, the layout distance becomes equal to or larger than the layout distance near the short axis. Therefore, the curvature of the shadow mask and the electron beam through hole array are set in proper condition, and mislanding of beam landing due to deformation or oscillation of the shadow mask can be reduced. At the same time, howling of the phosphor screen can be minimized.

Color cathode ray tube having particular arrangement of electron beam through hole arrays

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 having a reinforcing band, which constricts the outer periphery of a skirt portion of a vacuum envelope, arranged so as to fulfill a relation, b&gE;2.0a, where a is the distance between first and second planes along a tube axis, the first plane intersecting an end edge of the skirt portion and extending perpendicular to the tube axis, the second plane containing the central axis of stud pins supporting a shadow mask and extending perpendicular to the tube axis, and b is the distance between the first plane and a third plane along the tube axis, the third plane intersecting a side edge of the reinforcing band facing a vacuum envelope funnel.

Color cathode ray tube having reinforcing band arranged in a particular position relative to the position of stud pin

Provided is a color cathode ray tube, which comprises a panel including a substantially rectangular effective portion, of which the outer surface is a flat surface or a slightly curved surface, and a shadow mask having an effective surface opposite the inner surface of the effective portion of the panel. In this color cathode ray tube, the inner surface of the effective portion of the panel is a curved surface having a substantially infinite curvature radius RXp,in the major-axis direction on the major axis thereof near the center, a predetermined curvature radius RXp,in the major-axis direction near peripheral portions on the major axis, and another predetermined curvature radius in the minor-axis direction on the minor axis thereof. This color cathode ray tube, with its panel having the substantially flat outer surface, enjoys improved visibility and higher strength for the maintenance of the curved surface of the shadow mask.

Color cathode ray tube having particular effective inner panel surface and shadow mask effective surface shapes

Color cathode ray tube having a shadow mask with a plurality of strip shaped reinforcing beads

A shadow mask is arranged to face an inner surface of a substantially rectangular face panel. The shadow mask has a substantially rectangular mask body which has a number of apertures for passing an electron beam, and a rectangular mask frame which supports a peripheral edge portion of the mask body. The mask body is curved in a short axis direction, and is fixed to the mask frame in a state that an internal stress of a direction making small a radius of curvature of the short axis direction is applied. The shadow mask is manufactured in a manner that a rectangular flat mask is-plastically deformed so as to prepare the mask body having a curved surface such that a relation between a radius of curvature Rc of the short axis direction in the vicinity of the long axis and a radius of curvature Ra of the short axis direction in the vicinity of a long side becomes Rc<Ra, and thereafter, the mask body is fixed to the mask frame in a state of being elastically deformed in a direction in which a radius of curvature of the short axis direction becomes large.

Shadow mask for color cathode-ray tube and method of manufacturing the same

A shadow mask of a color cathode-ray tube includes a substantially rectangular mask main body and a rectangular mask frame attached an outer periphery of the mask main body. The mask main body has a substantially rectangular main surface portion formed of a curved face having a large number of electron beam passage apertures, the main surface portion having a longer axis and a shorter axis perpendicular to the longer axis, and a skirt portion raised in peripheral edges of the main surface portion. The skirt portion has a pair of longer side walls extending substantially in parallel to the longer axis, and a pair of shorter side walls extending substantially in parallel to the shorter axis. Each of the longer side walls includes a pressing portion located near the shorter axis so as to protrude toward the mask frame and pressing the mask frame.

Color cathode-ray tube with shadow mask mounting system

In a color cathode ray tube comprising a panel with a substantially rectangular effective portion whose outside face is almost flat or slightly curved and whose inside face has a curvature in the direction of minor axis near the short sides of the portion, and a fluorescent substance screen having a substantially rectangular effective region formed on the inside face of the effective portion of the panel, the short sides in the outer circumference of the effective region of the fluorescent substance screen are projected toward the center of the effective region. This improves the flatness of images appearing on the fluorescent substance screen provided on the inside face of the effective portion in the color cathode ray tube with the outside face of the effective portion of the substantially rectangular panel being almost flat and the inside face having a curvature in the direction of minor axis at least near the short sides.

A shadow mask opposing a phosphor screen includes a substantially rectangular mask body having a number of electron beam passage apertures, and a substantially rectangular mask frame having four side walls supporting a periphery of the mask body. Among the side walls, a pair of long side walls each has a central connecting portion which is located at a central portion thereof in lengthwise direction and fixed to the mask body, and a pair of protruding portions which are provided on both sides of the central connecting portion in the lengthwise direction and protrude in a direction apart from the mask body. Each protruding portion defines a gap between the side wall and the mask body, and a width of the gap gradually increases as it goes far from the central connecting portion.

Growing community of inventors

Fukaya, Japan

Shinichiro Nakagawa