| 摘要 |
PROBLEM TO BE SOLVED: To obtain a cathode-ray tube and an electron gun wherein an electron beam is just focused and just converged on a color phosphor screen so that an excellent spot characteristics can be obtained and cathode driving voltage can be lowered. SOLUTION: A plurality of small openings are provided so as to surround an optical axis Z in the center of the opening of the first and second grid G1 and/or the second grid G2 of the three-pole electrode 4 of the cathode-ray tube or the electron gun. The electric potential distribution is set so as to have electric field intensity between the second grid G2 and the third grid G3 to be more intense than the electric field intensity of the first grid G1 and the second grid G2. Thus the electron beam when passing the first grid G1 and the second grid G2 is formed into a parallel flux 25 almost parallel to the optical axis Z, and the small openings are formed into astigmatic shape.
|
