Hitachi, Ltd.

Hitachi Displays, Ltd.

Hitachi Display Devices, Ltd.

Toshifumi Komiya

Sachio Koizumi

Norio Iwamura

Yukio Suzuki

Satoshi Muto

Reiji Torai

Toshio Suzuki

A cold cathode fluorescent lamp includes a tube having an inner surface coated with a fluorescent film and tubular discharge electrodes disposed at both inner ends of the tube. Each discharge electrode has an opening facing a discharge area and includes a projection in the opening, the area of the projection being reduced by electric discharge.

Cold cathode fluorescent lamp and liquid crystal display device

A heat generating portion of a heater which is incorporated in an indirectly heated cathode structure of an electron gun for a cathode ray tube is formed by joining a first winding portion and a second winding portion which differ in the number of coil winding layers and by twisting and winding a joined body in a double helical structure. The present invention allows a cathode temperature to have a high temperature and hence, it is possible to enhance the electron irradiation characteristics even when a degree of in-tube vacuum is lowered.

Cathode ray tube

The indirectly heated cathode structure includes a base metal having a thermal electron emitting material layer, a cylindrical sleeve holding the base metal at one end portion thereof and housing a heating heater in the inside thereof, an support having a large-diameter portion and g a small-diameter portion, and a cathode disc having a large-diameter portion at the leg-portion-side of the heating heater and having a small-diameter portion at the heater-main-portion side of the heating heater, wherein an outer surface of another end portion of the sleeve and an inner surface of the small-diameter portion of the support are fixed to each other, and an outer surface of the large-diameter portion of the support and an inner surface of the small-diameter portion of the cathode disc are fixed to each other.

A cathode ray tube has a phosphor screen and an electron gun including an indirectly heated cathode structure and a plurality of electrodes disposed downstream of the indirectly heated cathode structure for projecting an electron beam toward the phosphor screen, and a deflection yoke for scanning the electron beam on the phosphor screen. The indirectly heated cathode structure includes: a base metal having an electron emissive material coating on an outer top surface thereof; a metal sleeve having the base metal attached to an end of the metal sleeve; a heater housed partly within the metal sleeve which includes a major heating portion formed of a spirally wound heating wire and leg portions formed of heating wires wound spirally in a plurality of layers; an insulating film covering the major heating portion and a portion of each of the leg portions continuous with the major heating portion; and a black coating film covering a portion of the insulating film extending from the major heating portion toward each of the leg portions, the whole of the black coating film being housed within the metal sleeve.

Cathode ray tube having an improved indirectly heated cathode structure

A cathode ray tube has an electron gun including an indirectly heated cathode structure having a heater therein. The heater has a major heating portion formed of a spirally wound heating wire and two leg portions connected to opposite ends of the major heating portion. The two leg portions are welded to electrical conductors for applying voltages thereto at portions in the vicinity of open ends of the two leg portions, respectively, and the heater is covered with an insulating film except for the portions for welding. The two leg portions includes at least five layers of winding formed by spirally winding heating wires identical with the heating wire of the major heating portion, and the numbers of turns per unit length in each of the at least five layers of winding are smaller than a number of turns per unit length of the heating wire of the major heating portion.

Cathode ray tube having an improved heater

A color cathode ray tube having at least an evacuated envelope comprising a panel portion having a phosphor screen formed on an inner surface thereof, a neck portion, and a funnel portion connecting the panel portion and the neck portion. A shadow mask is spaced from the phosphor screen and suspended within the panel portion, an in-line type electron gun is housed in the neck portion and include three cathodes, a first grid electrode spaced from the three cathodes and a plurality of electrodes spaced between the first grid electrode and the shadow mask for generating and directing three electron beams toward the phosphor screen. A deflection yoke is mounted in the vicinity of the junction between the neck portion and the funnel portion. The three cathodes are supported within three eyelets, respectively, and each of the three eyelets has a large-diameter upper portion facing the first grid electrode, a small-diameter lower portion for supporting the three cathodes and a funnel portion for connecting the large-diameter upper portion and the small-diameter lower portion, and being disposed within and bonded to a tubular cathode support at the large-diameter upper portion thereof by a bonding glass contained within the tubular cathode support. The bonding glass provides a protrusion beyond an upper open end of the tubular cathode support, and the protrusion is provided with a depressed step around a top edge thereof.

Cathode ray tube having an improved cathode structure

A cathode ray tube is provided with a phosphor screen and an electron gun including a cathode having an electron-emissive material layer formed on a surface of a cathode base metal. The electron-emissive material layer includes a first layer made of an alkaline earth metal oxide on the surface of the cathode base metal, a second layer on a surface of the first layer which is an alkaline earth metal oxide layer containing at least one rare earth metal oxide in a range of 0.1 to 10 weight percent, the at least one rare earth metal oxide having a particle size distribution in which the number of particles having a maximum diameter over 5 &mgr;m m is one or none, the number of particles having a maximum diameter in a range of from 1 &mgr;m to 5 &mgr;m is in a range of from 2 to 30, as measured in an area of 45 &mgr;m&times;45 &mgr;m at a center of a top surface of the second layer, the maximum diameter being defined as a perpendicular projection, onto a horizontal direction, of tangents to extremities of a profile of each of the particles. The cathode base metal is made chiefly of nickel and containing at least one reducing agent, and a thickness of a portion of the cathode base metal in contact with the electron-emissive material layer is in a range of 0.10 to 0.16 mm.

Cathode ray tube having an improved cathode

An electron gun for a cathode-ray tube for image display including a cathode having a sleeve made of a refractory metal, a support provided at one end of the sleeve and made of a refractory metal containing a reducing element, a heater arranged in a space defined by the sleeve and the support, and an electron emissive material layer for emission of electrons. The electron emissive material layer is mainly made of an oxide of an alkaline earth metal and contains an oxide of a rare earth metal. The electron emissive material layer is prepared by forming a first layer on the support by spraying, and forming a second layer on the first layer by spraying. A dispersion amount of an oxide of a rare earth metal in the second layer is larger than that in the first layer and a first grid electrode is provided adjacent the cathode. The grid electrode has an electron beam passage hole for the electrons from the electron emissive material layer, and the electron beam passage hole has a diameter which is less than 0.4 mm.

ELECTRON GUN FOR CATHODE-RAY TUBE FOR IMAGE DISPLAY HAVING AN ELECTRODE WITH REDUCED ELECTRON BEAM PASSAGE HOLE AND A CATHODE WITH AN ELECTRON EMISSIVE LAYER MAINLY MADE OF AN OXIDE OF AN ALKALINE EARTH METAL AND CONTAINING AN OXIDE OF A RARE EARTH METAL

A color cathode ray tube includes an electron gun having a plurality of cathodes and a cup-shaped first grid electrode spaced from the cathodes. The plurality of cathodes are supported within a plurality of eyelets corresponding to the number of the cathodes, respectively. The eyelets are disposed within and bonded to a tubular cathode support by bonding glass contained within the tubular cathode support, and satisfy the following relationship: (1.4 times a beam spacing S between two electron beams from the two adjacent cathodes divided by an outside radius of the eyelets-1.4 mm).gtoreq.(a height of the eyelets protruding beyond the top surface of the bonding glass).gtoreq.(0.98 times the beam spacing S divided by the outside radius of the eyelets-1.4 mm).

A cathode-ray tube is provided with an electron gun having a cathode and a control electrode and some other electrodes. The cathode includes an electron emissive material layer for emission of electrons through a hole in the control electrode. The hole in the control electrode has a diameter substantially in a rage of from 0.3 mm to 0.4 mm. The electron emissive material layer has a first layer made of an oxide of an alkaline earth metal formed on a support and containing no oxide of a rare earth metal, and a second layer made of an oxide of an alkaline earth metal formed on the first layer and containing an oxide of a rare earth metal substantially in an amount of from 0.8 wt % to 5.0 wt %.

Electron gun for a cathode-ray tube for image display having an

A cathode for an electron tube has an electron emissive material layer on the surface of a cathode base metal. The electron emissive material layer has a three-layer structure composed of a first layer made of an alkaline earth metal oxide which is formed on the surface of the cathode base metal, a second layer which is an alkaline earth metal oxide layer in which a rare earth metal oxide is dispersed, which is formed on the surface of the first layer, and a third layer made of an alkaline earth metal oxide which is formed on the surface of the second layer.

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Mobara, Japan

Toshifumi Komiya