| 摘要 |
1,225,845. Cathode-ray storage tubes. RCA CORPORATION. 22 Nov., 1968 [22 Nov., 1967], No. 55459/68. Heading H1D. A target for a cathode-ray storage tube comprises a metal mesh 22, coated with insulating material 24 except on one side of the target, the interstices of the mesh being filled with semiconductor elements 26 of one conductivity to form storage elements each of which is surrounded by a layer 28 of semi-conductor of the opposite conductivity. The mesh may be of nickel with 1000 openings per linear inch and thickness of 3-5 mils; the insulation 24 may be of SiO 2 or Si 3 N 4 1-3 microns thick, and the semi-conductor layers may be silicon or germanium containing the appropriate impurities to produce the desired conductivity, the element 26 being preferably P-type and the layer 28 N-type. In one mode of operation (Fig. 1, not shown) the layer 28 is earthed, the mesh 22 is at a potential of - 3 to- 20 v., and a negative charge image is formed on one side of the target from a photo-cathode maintained at - 1500 v.; any secondary emission produced is suppressed by the bare mesh 22 which is at a negative potential. The charge image is read by a scanning beam from a cathode at - 500 v. which charges the storage elements 26 positively by secondary electron emission until they reach the potential of the layer 28 when the PN junctions become conductive; a ring-shaped electrode near the target collects the emitted secondary electrons, and the signal output is taken from the mesh 22. As an alternative to a photo-cathode, the target may be charged by a scanning beam. If the storage elements 26 are of N-type the charging is positive by secondary emission and the reading is by a low velocity electron beam as in an orthicon. |
