| 摘要 |
Colour image tube comprising a linear electron gun whose electrodes define a beam formation region, a prefocusing region and a main focusing region. The region for formation of the beam of the gun comprises a cathode (34), an electrode G1 (36), an electrode G2 (38) and a first part (60) of an electrode G3 (40). The prefocusing region incorporates a second part (62) of the electrode G3, an electrode G4 (42) and a first part (68, 70) of an electrode G5 (44). The main focusing region incorporates a second part (72) of the electrode G5 and an electrode G6 (46). The improvement comprises the astigmatic beam formation region, the astigmatism consisting of vertically elongated slits (56) superposed on each of the three circular apertures of the electrode G1, on the side of the latter which faces the electrode G2. The prefocusing region is astigmatic, the astigmatism consisting of horizontally elongated edges (92, 94) on facing parts of the electrodes G5 and G6. <IMAGE>
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