| 摘要 |
PURPOSE:To match the optimum focusing conditions of the electron beams at the center and both sides by making thicker the electron beam transmitting hole plate at the center of G2 electrode forming a 3-pole bulb of electron gun electrode structure than the electron beam transmitting hole plates in both sides. CONSTITUTION:A 3-pole bulb of electron gun electrode structure is formed by three cathode structures 10R, 10G, 10B arranged in a line and the G1 electrode, G2 electrode 20 and G3 electrode 13-1 which are arranged opposing to said structures and have the electron beam transmitting holes respectively. Thickness of the center electron beam transmitting hole 20G of G2 electrode 20 is set to 1.1- 1.4 times that of external electron beam transmitting holes 20R, 20B in both sides. Accordingly, even if field distortion at the center of electron lens is larger than that at both external sides, the center electron beam enters the main lens with a divergence angle than that of electron beams at both external sides and thereby the focusing conditions can be matched substantially and image quality can be improved. |
