Hitachi, Ltd.

Hitachi Device Engineering Co., Ltd.

Hidemasa Komoro

Shoji Shirai

Kazuo Majima

Yukihiro Izumida

Masakazu Fukushima

Yoshiaki Takahashi

Masaaki Yamauchi

Minoru Yabe

Mamoru Ikeda

Kenichi Matsuda

Akio Yamaguchi

Tetsuya Enomoto

Masakatsu Horiuchi

A color cathode ray tube includes an evacuated envelope having a panel portion with a phosphor screen formed on an inner surface thereof, a neck portion, and a funnel portion connecting the panel portion and the neck portion, and an electron gun housed in the neck portion. The electron gun has a cathode and a plurality of focus grid electrodes including grid electrodes for forming a multistage focus lens for focusing an electron beam emitted from the cathode. The cathode and the focus grid electrodes are fixed in predetermined axially spaced relationship by a pair of bead glass. The electron gun is provided with a voltage divider for producing at least one voltage other than a voltage supplied from outside the evacuated envelope, the voltage divider is made of at least one resistor and is fabricated as a separate element from the bead glass, and at least one of bead glass is provided with a recess for receiving the voltage divider in a surface thereof on a side thereof facing away from the cathode and the focus grid electrodes.

Color cathode ray tube having an internal voltage divider

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 a color picture tube consists of a triode that generates a plurality of electron beams and a main lens which focuses and converges the electron beams. The main lens can be divided into two types, i.e., a pair of bi-potential focusing electron lenses and a combination of the bi-potential focusing electron lens and a uni-potential focusing electron lens. The electrodes constituting the main lens have apertures for permitting the transmission of a plurality of electron beams. The center axes of apertures are deviated toward the center axis of the embodiment of electron gun away from the axes of initial paths of the electron beams emitted from the triode.

Electron gun structure for converging electron beams

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 for a color picture tube comprises opposing cup-shaped electrodes each having a plurality of openings laterally aligned in a row, the electrodes being combined such that the openings face each other to form electron lenses. The openings are formed in flat bottom walls of said electrodes, a width of a bridge portion between adjacent openings is 0.5 to 1.5 times a thickness of the bottom wall of each electrode, and corrective plate electrodes are arranged to oppose bridge portions with a predetermined distance therefrom. The electrodes are combined such that spherical aberration of said electron lenses as a whole can be reduced when one of the electrodes is applied with a voltage which is higher than that applied to the other.

Electron gun for color picture tube

Growing community of inventors

Chiba, Japan

Hidemasa Komoro