| 摘要 |
PROBLEM TO BE SOLVED: To provide a color cathode ray tube(CRT) device that ensures a good quality of displaying a picture by improving the shape of beam spot throughout the screen. SOLUTION: In the color CRT device, an electron gun 26 comprises an electron beam generator for generating three electron beams aligned, which includes a cathode, as well as first, second, third, and fourth electrodes G1, G2, G3, and G4. The first electrode is grounded, the second electrode being applied with a lower voltage than the focusing electrode 52, the third electrode connected to the focusing electrode and applied with a dynamic voltage obtained by adding a voltage rising according to increase of the deflection angle of the electrode beam to a constant focusing voltage, and the fourth electrode applied with a higher voltage than the third electrode. The lens consisting of the second and fourth electrodes are designed to enhance the astigmatism that the vertical focusing gets stronger than the horizontal focusing along with the increase of the deflection angle of the electron beam.
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