Kabushiki Kaisha Toshiba

Tokyo Shibaura Denki Kabushiki Kaisha

Kiyoshi Tokita

Michio Nakamura

Masatsugu Inoue

Takeshi Fujiwara

Toshinao Sone

Kazunori Nakane

Hiroshi Urata

Tooru Takahashi

Kaneharu Kida

Toshiaki Kanemitsu

Hidemi Matsuda

Tetsuo Hasegawa

Takashi Murai

Norio Koike

Kazunori Satou

Hidetoshi Yamazaki

Akira Fukuoka

In a method of testing a color cathode ray tube, an electron gun assembly is energized to emit electron beams and only a horizontal deflection magnetic field is applied to the electron beams so that a line image is displayed on a screen. A degaussing coil is located in front of the panel and a degaussing magnetic field having a frequency the same as that of a commercial power source. Thereafter, the degaussing coil is moved in a direction away from the panel and is deenergized when the coil is removed from the panel at a predetermined distance. A vertical deflecting coil is energized to display an image and a picture quality of the tube is tested.

Method of degaussing a color cathode ray tube

A color cathode-ray tube apparatus comprising a video signal generator, a delay circuit, an electron gun assembly, a deflection yoke, a shadow mask, and a phosphor screen. The signal generator generates three video signals simultaneously. The delay circuit delays the first and second video signals with respect to the third video signal. The screen has phosphor elements regularly arranged. The electron gun assembly generates three electron beams at different times, in response to the three signals output by the delay means. These beams are applied to the phosphor screen, and the phosphor elements of the screen emit red light, green light and blue light. Any three electron beams the gun assembly emits simultaneously form three beam spots on the screen. These spots overlap for a distance longer than half the horizontal diameter of a beam spot formed by an electron beam of the greatest current which the gun assembly can generate. The shadow mask, located between the phosphor screen and the gun assembly, controls the beams, making them land at desired positions on the phosphor screen. The deflection yoke deflects the beams in the horizontal and vertical directions, such that the electron beams scan the entire screen. The beams, deflected in the horizontal direction, land at substantially the same point on the screen, forming a color pixel thereon.

Color cathode-ray tube apparatus

The invention provides a novel color cathode ray tube apparatus incorporating an eight-pole permanent magnet means, and thereby deflective aberration of electron beams caused by deflected magnetic field can securely be minimized. Integral structure of a plurality of magnetic poles permits the concerned to easily form up the eight-pole permanent magnet ring.

Color cathode ray tube apparatus

In a cathode ray tube, a first pair of permanent magnet pieces are arranged along a horizontal direction and fixed on an end portion of a deflection unit at an electron gun side in such a manner that poles of one of the magnet pieces face the other poles of the other magnet piece. A second pair of permanent magnet pieces are arranged along a vertical direction, separated from the first pair of permanent magnet pieces by being fixed on a neck portion, forward of the electron gun assembly, and in such a manner that poles of one of the, magnet pieces face the other poles of the other magnet piece.

Cathode ray tube which improves deflection aberration

A degaussing current whose frequency is L Hz is supplied to a degaussing apparatus, and a constant amplitude vertical deflection current whose frequency is M Hz is supplied to a deflection yoke. The degaussing current is an A.C. current, and its frequency L Hz is determined such that the value of M/L is not an integer.

Color cathode ray tube set

Magnets for applying a pincushion type magnetic field to three electron beams emitted from an electron gun assembly is arranged between the deflection device and the lens unit of the electron gun assembly. The pincushion type stationary magnetic field produced by the magnets correct deflection aberrations of the electron beams due to the magnetic field of the deflection device and improves the focusing characteristics on the periphery of a screen.

According to the color cathode ray tube of the present invention, a magnetic resistance section is provided between a shadow mask and a mask frame. The magnetic resistance section comprises at least one of magnetic resistance members and a gap which is provided between the shadow mask and the mask frame. The magnetic resistance section serves to reduce a landing error of electron beams on a phosphor screen.

Color cathode ray tube

In a color cathode ray tube according to this invention, there are provided a plurality of first elastic supporting members welded to a mask frame to support a shadow mask in a panel and each having a metal plate, and at least one second elastic supporting member each having a metal plate and a washer. The area of a polygon formed on a plane lying at right angles with the tube axis and having apices corresponding to the first elastic supporting members is at least about 1/2 of the area of the substantial quadrangle formed by projecting the shadow mask on said plane.

Method and apparatus for supporting a shadow mask

A color picture tube of this invention has a CRT envelope having a substantially rectangular front panel, a phosphor screen formed on an inner surface of the front panel, a shadow mask which is detachably mounted on the panel adjacent to the phosphor screen by a supporting assembly, and a frame surrounding the shadow mask. The supporting assembly has a plurality of stud pins which project from the four corners of the front panel and leaf springs which are fixed at one end to a corresponding corner of the frame are detachably engaged at the other end with a corresponding stud pin. Each leaf spring has an elastically deformable portion between one end portion fixed to the frame and the other end portion engaged with the corresponding one of the stud pins. Angle .beta., defined by the axis of the elastically deformable portion a central line axis of the CRT envelope, and angle .alpha., defined by a line connecting an end portion of the elastically deformable portion on the side of the frame and the stud pin and the central line axis of the CRT envelope, have the following relation: .beta.&lt;.alpha.

Color picture tube with shadow mask support assembly

In a color cathode ray tube, a shadow mask and/or a panel is formed into the following shape. In the shadow mask and/or the panel, a radius of curvature at a central portion in a section taken along an X-Z parallel plane is larger than that at an effective diameter edge portion on the Y axis, and a radius of curvature at an effective diameter edge portion on the X axis is smaller than that at a diagonal effective diameter edge portion. In the panel, a difference between a thickness at an effective diameter edge portion and a thickness on the X axis in a section of the panel taken along a Y-Z parallel plane is maximum at a position between the center of the panel and the effective diameter edge portion on the X axis.

A color picture tube comprises a panel of a substantially rectangular shape, a phosphor screen formed on the inner surface of the panel, a stud pin which is made of a rod with a tapered portion and which is mounted on the inner side surface of the panel, a spring member having a through hole and fitted with the tapered portion of the stud pin through the through hole, and a shadow mask mounted on the panel through the stud pin and the spring member so as to be opposite or adjacent to the phosphor screen, wherein if the spring member is in contact with the stud pin at least two positions, the following inequality is satisfied:

Color picture tube with shadow mask supporting assembly

A color picture tube having a shadow mask structure with a shadow mask and a mask frame supporting the shadow mask facing a phosphor screen inside a panel comprises a plurality of V-shaped support members, each having a folded portion apart from a sidewall of the mask frame and two arm portions extending from the folded portion. The support members support the shadow mask structure to the panel to control a relative distance beween the phosphor screen and the shadow mask according to thermal expansion of the shadow mask structure or the panel, whereby positions impinged by an electron beam on the phosphor screen remained invariably.

Color picture tube with support members for the mask frame

A deflection device generating magnetic field for electron beam deflection comprises, a cylindrical mold, a horizontal deflection coil provided inside the mold, a magnetic core attached to outside of the mold, a vertical deflection coil wound on the core, and magnetic member means for modifying deflection field distribution, interposed between the mold and vertical deflection coil. The deflection device further includes a porous ceramic layer for heat dissipation coated on at least a part of the outer surfaces of the mold, horizontal deflection coil, vertical deflection coil and magnetic member means.

Cathode ray tube deflection device having heat dissipation means

The shadow mask of a color cathode ray tube is arranged in the vicinity of a phosphor screen. The shadow mask is provided with through-holes that select the electron beams emitted from the electron guns. A layer comprising, as a filler, one or other of a metal, metal oxide, metal carbide, metal nutride, or a mixture of two or more of these, for example zirconium powder and, as a binder, one of an amorphous metal oxide compound, amorphous metal hydroxide compound or a mixture of these, for example silicon oxide, is formed on the surface of the shadow mask. This layer increases thermal radiation of the shadow mask, reduces electron scattering, and raises the residual emissivity.

A color picture tube has: an envelope; a phosphor screen formed on the inner surface of the envelope; a shadow mask which is disposed in the envelope and in a vicinity of the phosphor screen and which has a main surface portion with a number of apertures; and an electron gun for emitting electron beams which are selectively transmitted through the apertures and are bombarded on the phosphor screen so as to emit multi-color light. A layer having a ceramic material as a major constituent is chemically bonded to that surface of the main surface portion of the shadow mask which is located at the side of the electron gun, and a conductive layer is formed on the layer. The charge-up phenomenon of the layer having a ceramic material is prevented by the conductive layer.

Growing community of inventors

Fukaya, Japan

Kiyoshi Tokita