Hitachi, Ltd.

Hitachi Electronic Devices Co., Ltd.

Hitachi Electronic Devices, Ltd. Co.

Kotaro Aoki

Kazumasa Hirai

Kouichi Saitou

Yasuo Tanaka

Tetsuo Asano

Nobuyuki Suzuki

Shoji Shirai

Katsumi Hirota

Takashi Hoshimure

The present invention aims at maintaining the high focusing performance at a low deflection power in a single-beam projection tube which is used as a projection type TV receiver or a projector and is operated at a high voltage and with a high current. The neck outer diameter of a portion on which a deflection yoke is mounted is made smaller than the neck outer diameter of a portion which accommodates an electron gun. The maximum anode voltage of the projection tube is set to equal to or more than 25 kV and the maximum beam current is set to equal to or more than 4 mA

Projection tube having different neck diameters

A projection tube having a high focusing performance at a low deflection power includes a funnel, a neck portion and a stem portion which seals the neck portion. The neck portion of the projection tube includes a first neck portion which is connected to the funnel and has a first neck outer diameter, and also includes a second neck portion which accommodates an electron gun and has a second neck outer diameter which is larger than the first neck outer diameter.

The present invention aims at maintaining the high focusing performance with a low deflection power in a projection tube which is used as a projection type TV receiver or a projector and is operated at a high voltage and with a single-electron-beam high current. A neck outer diameter of a portion on which a deflection yoke is mounted is made smaller than a neck outer diameter of a portion which accommodates an electron gun. A final electrode of the electron gun has a diameter thereof gradually decreased toward a phosphor screen. The maximum anode voltage of the projection tube is set to equal to or more than 25 KV and the maximum beam current is set to equal to or more than 4 mA.

A projection type cathode ray tube device includes a panel, a neck, a funnel connecting the panel to one end of the neck, and a stem closing the other end of the neck. An electron gun is housed in the neck for projecting an electron beam toward a phosphor screen on the panel. The neck includes a small-diameter neck portion disposed on its funnel side, a large-diameter neck portion disposed on its stem side, and a neck junction region connecting the small-diameter neck portion and the large-diameter neck portion. A deflection yoke is disposed in a vicinity of a transition region between the funnel and the small-diameter neck portion. A convergence yoke for generating a beam-convergence magnetic field is disposed to extend from the large-diameter neck portion and surround at least a portion of the neck junction region.

Growing community of inventors

Mobara, Japan

Kotaro Aoki