| 摘要 |
PROBLEM TO BE SOLVED: To shorten the total length of a cathode-ray tube for a projection type TV, without losing its focus characteristics by optimizing the electron gun. SOLUTION: In the cathode-ray tube, in which a positive electrode is composed of that where a large diameter cylindrical part of a fluorescent material screen side and a small diameter cylinder part of the cathode side positive electrode are jointed, and a focus electrode is composed of that where the large diameter cylindrical part having a large diameter than that of the small-diameter cylindrical part of the positive electrode and the small-diameter cylindrical part having a small diameter than that of the small-diameter cylindrical part of the positive electrode are jointed, and the large-diameter cylindrical part of the focus electrode is arranged coaxially in the large-diameter cylindrical part of the positive electrode, and the first electrode arranged counterposed at the cathode side of the focus electrode is electrically connected with the positive electrode in the tube; if in the tube shaft direction of focus electrode is taken as LG4 (mm), and the distance from the side edge face of the fluorescent material screen of the focus electrode to the center of the phosphor screen is taken as LP (mm), the relation between LG4 and LP set with -LP+184.9>=LG4>=0.0004 LP3-0.1571 LP2+21.006 LP-922.41, and LP>=131.7.
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