| 摘要 |
705,533. Television pick-up tubes. RADIO CORPORATION OF AMERICA. Feb. 13, 1952 [Feb. 24, 1951]. No. 3841/52. Class 39(1) [Also in Group XXXVI] A photo-conductive target electrode for a television pickup tube comprises in this order. a transparent conductive film 42, a thin film of one photoconductive material 44 and a second film 45 of a different photo-conductive material, the two materials having different colour response characteristics. The first film may be red sensitive e.g. antimony trisulphide, cadmium selenide or metallic selenium and .1-.5 microns thick; the second film is amorphous selenium and its thickness large compared with that of the first film, e.g. 2-5 microns. The trisulphide film is formed by evaporation in a vacuum at 450‹C which is stopped when the colour of the film has passed from a golden yellow to a yellowish brown. The amorphous selenium is also applied by evaporation on vacuum, the first layer being held below 50 ‹C, and the thickness of the applied film controlled by observation through a diffraction grating. The target is mounted in a cathode-potential-stabilized tube with magnetic focusing and deflecting and with a fine mesh screen connected to and across the anode wall coating, Fig. 1 (not shown). Specification 672,052 is referred to |
