Color picture tube device

Abstract

Abstract PURPOSE:To prevent the overfocusing of electron beam on the peripheral edges of a fluorescent screen by applying a dynamic focusing voltage changeable synchronously with the horizontal or vertical deflection of electron beam to the grid of an auxiliary electron lens. CONSTITUTION:The electron gun 25 of a color picture tube is provided with the cathode 25, first grid 33, second grid 34, third grid 35, fourth grid 36, fifth grid 37, sixth grid 38, and convergence electrode 39, and a double type of the main lens system is made up of an auxiliary electron lens and the main electron lens. And, to the fourth grid 36, a voltage changeable synchronously with the horizontal or vertical deflection of electron beam, together with a 500-700V DC focusing voltage, is applied from the dynamic focusing voltage generator 41. Thus, the electron beams 26, 261, and 262 which always focus on the fluorescent screen 21 can be emitted and the overfocusing on peripheral edges can be prevented.

Inventors

• 👤 Shigeo Takenaka
• 👤 Eizaburo Hamano
• 👤 Eiji Kanbara

Bibliographic Details