| 摘要 |
825,876. Cathode-ray tubes. ZENITH RADIO CORPORATION. June 29, 1956 [June 30, 1955], No. 20200/56. Class 39(1). [Also in Groups XXXIX and XL(b)] A "flat" cathode-ray tube, e.g. for use in a television receiver or in a switching circuit, comprises a set of electrostatic mirrors 21 for deflecting the beam A, Fig. 1, successively into a plurality of paths across the target 40. The beam is then deflected into impact with the target by a set of deflection plates 34 or coatings on an insulating base, or by a second set of electrostatic mirrors. Individual cycles of sawtooth scanning voltages are applied to the deflection plates or mirrors (see Group XL(b)). In a colour television tube, Fig. 6, three beams 55R, 55G and 55B are reflected at mirrors 80 to fall on colour strips R, G, B. Mirrors 80 are plates 86 with mesh portions 87, or may consist wholly of mesh. Post-deflection accelerating voltages are applied between a screen 41 and the target 91. The target comprises a conductive film 62 deposited on the phosphors, or the surface of the base 60 may be conductive e.g. by iridizing. In a switching tube the target consists of rows and columns of individual target plates, e.g. 10 x 10. A second electron gun 155, Fig. 8, may be included in the tube to scan extensions or cup-shaped sections 138 formed in the mirror plates 117 to energize them in sequence. The cup-shaped sections may be coated with graphite to reduce secondary electron emission. The mirror electrodes may be channel shaped to reduce the cross-sectional area of the beam.
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