Hitachi, Ltd.

Yukihiro Izumida

Kazuo Majima

Hidemasa Komoro

Shoji Shirai

Takao Kawamura

Tetsuo Kumazawa

Hiroshi Fukushima

Mamoru Ikeda

Akio Yamaguchi

Kitaro Sasaki

Yoshinobu Miyamoto

Takeo Takemoto

Kihachiro Koizumi

Masaru Nakazawa

Yoshihiko Miyata

Masakatsu Horiuchi

An electron gun for a color picture tube has at least a cathode, a control grid, an accelerating grid, a focus grid and an anode, each of which has three apertures aligned in line. The focus grid and the anode made of elongated plates serves as main lens electrodes, and the apertures of the focus grid and the anode constitute a main lens assembly. The three apertures of each of the elongated plates has a central aperture defined by two first curves arcuated outward, two side apertures each of which is defined by a second curve as an inner half arcuated inward and a third curve as an outer half arcuated outward, the first and second curves being less arcuated than the third curve. The three apertures are aligned such that the major axes thereof are parallel to a shorter axis of the elongated plate and are located at equal intervals. The three apertures are spaced apart from each other through corresponding bridge portions. The third curve of each of the two side apertures is apart from a corresponding end of the elongated plate along the longitudinal direction.

Electron gun for color picture tubes having uniquely formed lens

An electron gun for color picture tube has a focusing electrode and an anode electrode respectively formed of an oval thick plate for forming main focusing lenses. Each of the focusing electrode and anode is formed with three electron beam passing holes arranged in line in a direction orthogonal to a tube axis of the picture tube. The focusing electrode and the anode are arranged to oppose each other with a distance therebetween such that their corresponding electron beam passing holes oppose each other. When predetermined voltages are applied to the focusing electrode and anode, main lenses are formed between the respective opposing holes. As viewed along the tube axis, the in line electron beam passing holes of each electrode include two outer electron beam passing holes each having an outer half in the form of a semi-circle and an inner half in the form of a semi-ellipse having a diameter of the semi-circle as its major axis and a central electron beam passing hole in the form of an ellipse having a major axis which is equal to the diameter of the semi-circle and which extends in a direction orthogonal to the direction of arrangement of the electron beam passing holes.

Electron gun for color picture tube with electrostatic focussing lens

An electron gun of in-line type for color picture tube including a pair of electrodes for an electrostatic focusing lens is disclosed. Each of the pair of electrodes has three electron beam passing holes arranged in line. Each of the electron beam passing holes is so shaped that the maximum dimension in the direction in which the electron beam passing holes are arranged in line is smaller than that in the direction perpendicular to the first-mentioned direction, and that the maximum dimension in the latter direction is larger than the center-to-center spacing between the electron beam passing holes. At least part of the electrode surfaces including the opening edges of the three electron beam passing holes is a curved surface, so that the distance between the surfaces of the pair of opposite electrodes is made different in value along each opening edge.

Electron gun for color picture tube

There is disclosed a direct-heated cathode structure which comprises an insulating substrate; a pair of conductive supporting rods penetrating the substrate in the direction substantially perpendicular to the surface of the substrate and fixed tightly to the substrate; and a conductive member made of a single metal plate and including a first portion which is arranged in a plane spaced apart from the surface of the substrate by a predetermined distance and substantially parallel to the surface of the substrate and is coated with an electron emissive material, second portions which are extended from the first portion in the above-mentioned parallel plane substantially symmetrically with respect to the first portion, third portions which are extended from the end of extension of each of the second portions in the direction substantially perpendicular to the surface of the substrate toward the substrate, and fourth portions which are extended from the ends of the third portions in the direction substantially parallel to the surface of the substrate in the same plane as the third portions and are fixed to the supporting rods in the neighborhood of the end of extension of the fourth portions. Each of the first, second and third portions has a side wall provided along at least a part of the edges of these portions and extending in the direction substantially perpendicular to the surfaces of these portions.

Direct-heated cathode structure

There is disclosed a support structure for a directly-heated cathode in a cathode ray tube, for supporting the cathode by fastening the strip leads of the cathode to support rods piercing and rigidly fixed to a base of insulating material through resistance welding. The support rods are provided in their proper positions respectively with protrusions having top plane areas to be contacted with the surfaces of the strip leads and the cathode is supported by fastening the strip leads to the protrusions through resistance welding. The length of the top plane area of the protrusion extending in the direction along the width of the strip lead is 30 to 80% of the size of the width of the strip lead.

Support structure for directly-heated cathode of cathode ray tube

In an electron gun assembly for use in multi-beam type cathode ray tube of the type including a plurality of grid structures in which the groups of the grid electrodes of respective guns are formed as integral units, the grid electrodes of each group are impressed with the same potential and perform the same function, and wherein an electron lens is formed between adjacent grid structures, an assembly of a plate member or a superposed plate member is secured to one or both of the opposing ends of the grid structures. Each plate member is provided with a plurality of openings which are arranged to correspond to a predetermined arrangement of a plurality of electron guns, and each opening is surrounded by an axial edge. The edges function to prevent electric fields formed by the openings from being affected by the side walls of the grid structures opposing the openings thereby decreasing the astigmatism of the main electron lens.

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Mobara, Japan

Yukihiro Izumida