Matsushita Toshiba Picture Display Co., Ltd.

Tsutomu Takekawa

Hirofumi Ueno

An in-line type electron gun using a field superimposing type main lens system is provided that can attain good focusing properties by decreasing the size of the electron beam spot on the entire surface of the phosphor screen without being formed to be mechanically large. A field superimposing type main lens is formed by disposing two tubular electrodes opposite to each other and disposing a plate-like field correction electrode on each of the tubular electrodes on the sides not opposite to each other. On each of the opposite sides of the two tubular electrodes, an opening is formed by an edge portion and a folded portion. The shape of the opening may be an elongated flat-sided oval shaped aperture (laterally elongated aperture) that is formed by straight lines and semicircles and has a major diameter in the horizontal direction and a minor diameter in the vertical direction. The in-line type electron gun is configured such that a relationship B&#x3c;A is satisfied, where A represents a minor diameter of the opening in the tubular electrode to which a relatively low voltage is applied, and B represents a minor diameter of the opening in the tubular electrode to which a relatively high voltage is applied.

In-line type electron gun and color cathode ray tube apparatus using the same

A main lens is formed by a focus electrode, an intermediate electrode, and an anode electrode successively arranged in a traveling direction of an electron beam. The focus electrode and the anode electrode respectively have an electron beam passage aperture common to three electron beams, having a major axis in a horizontal direction in a portion opposed to the intermediate electrode, and three electron beam passage apertures through which the three electron beams pass are formed respectively in the focus electrode and the anode electrode. Aperture dimensions in a vertical direction of the electron beam passage apertures common to the three electron beams formed respectively in the focus electrode and the anode electrode are smaller than those in the vertical direction of the electron beam passage apertures formed in portions of the intermediate electrode respectively opposed to the focus electrode and the anode electrode. This can provide a color Braun tube apparatus that has less moire while having satisfactory focus performance over the entire surface of a phosphor screen, and in which there are no increase in the cost of a driving circuit and the decrease in withstand voltage characteristics.

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Ibaraki, Japan

Tsutomu Takekawa