Hitachi, Ltd.

Hitachi Electronic Devices Co., Ltd.

Hitachi Electronic Devices, Ltd. Co.

Kouichi Saitou

Kotaro Aoki

Yasuo Tanaka

Tetsuo Asano

Kazumasa Hirai

Nobuyuki Suzuki

Shoji Shirai

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.

Growing community of inventors

Chonan, Japan

Kouichi Saitou