Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The present invention realizes a cathode ray tube which holds the stable electron emission characteristics when the cathode ray tube is operated in a high current density state for a long time. An electron emissive material layer which constitutes a cathode is formed by dispersing a scandium compound having an average particle size of equal to or less than 1.2 &mgr;m to an oxide layer formed of alkaline earth metal (barium, strontium, calcium) oxide, wherein an atomic weight ratio of scandium with respect to strontium is set to a value within a range of 0.003 to 0.3. A base metal includes a reducing metal containing nickel as a main component and a plate thickness of a surface of a top portion of the base metal which comes into contact with the electron emissive layer is set to a value equal to or more than 0.17 mm.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A cathode ray tube has an electron beam generating section including an indirectly heated cathode structure and first and second electrodes arranged in the order named. The cathode structure is composed of a cathode sleeve for housing a heater therein, a cathode base metal disposed at an end of the cathode sleeve facing toward the first electrode, and an electron emissive oxide layer disposed on the cathode base metal. The electron emissive oxide layer is formed with a depression on a surface thereof facing the electron beam transmissive aperture in the first electrode. A maximum diameter of the depression is smaller than a maximum diameter of the electron beam transmissive aperture in the first electrode, and a maximum depth of the depression is smaller than the maximum diameter of the depression.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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).

Abstract: 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 %.

Abstract: 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.