Patent ID: 7315113

Claim:
A color cathode-ray tube, comprising: an envelope having a funnel composed of a funnel portion and a neck, and a panel; a phosphor screen provided on an inner wall of the panel; an electron gun provided in an inner space of the neck, and having a beam generating portion for controlling generation of three electron beams arranged in an in-line direction, a plurality of focusing electrodes for controlling a focusing of the three electron beams, and an anode; and an inner conductive film formed on an inner wall of the funnel portion and in a part of an inner wall of the neck, and electrically connected to the anode, the color cathode-ray tube further comprising a conductive film isolated from the inner conductive film on the inner wall of the neck, wherein, among the plurality of focusing electrodes, an electrode placed at a position closest to the anode is an anode-side focusing electrode, and a position P 0 is defined as a position in a tube axis direction of an end on the anode side of the anode-side focusing electrode placed at a position closest to the anode side, among electrodes supplied with substantially the same voltage as that of the anode-side focusing electrode and arranged continuously from the anode-side focusing electrode, a position P 1 is defined as a position in the tube axis direction of an end on the beam generating portion side of an electrode placed at a position closest to the beam generating portion side, and in the tube axis direction, a position PL 1 is defined as a position of an end on the beam generating portion side of the conductive film, and a position PL 2 is defined as a position of an end on the panel side of the conductive film, in the tube axis direction, the position P 0 is placed between the position PL 1 and the position PL 2 , assuming that a distance in the tube axis direction from the position P 0 to the position PL 1 is L 1 , a distance in the tube axis direction from the position P 0 to the position PL 2 is L 2 , and a distance in the tube axis direction from the position P 0 to the position P 1 is L 3 , the following relationships: L1>L2 L1<L1 are satisfied, and in a direction orthogonal to a tube axis and the in-line direction, a range occupied by the conductive film includes and is larger than a range occupied by the anode-side focusing electrode.