| 摘要 |
PROBLEM TO BE SOLVED: To provide an electron gun for a cathode-ray tube capable of achieving, without requiring complex circuits, a cathode-ray tube which displays two display modes with different optimum values of focusing voltages, with both modes in good focused conditions, and a cathode ray tube having the electron gun. SOLUTION: A primary lens PL and a main lens ML are formed with common electron beam holes for two electron beams emitted to phosphors of the same color on the cathode ray tube. Of electron beam holes in a first and second electrodes 11 and 12, the one through which one of the electron beams passes has a larger diameter while the other through which the other of the beams passes has a smaller diameter. Further, at least one or more of a total of four elements, that is, the interval between a cathode K and the first electrode 11, the thickness of the first electrode 11, the interval between the first electrode 11 and the second electrode 12, and the thickness of the second electrode 12, are set to differ depending on the different portions through which the two electron beams pass. The electron gun emitting the two different beams alternately and the cathode-ray tube having the electron gun are formed.
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