Speicherroehre

摘要

1290782 Cathode-ray storage tubes RCA CORPORATION 8 Jan 1970 [8 Jan 1969] 1014/70 Heading H1D The target of a cathode-ray storage tube comprises a substrate of N+, P or P+ type semiconductor on which are provided storage regions formed of an insulating compound of a semiconductor material. The semi-conductor may be silicon or germanium and the insulating compound the dioxide or nitride. In Fig. 2 the insulation 34 is in the form of a grid with square apertures exposing parts of the surface of the substrate; if the layer 34 is of silicon dioxide it is preferably less than 3 microns thick for ease of fabrication. In modified constructions, Figs. 3 and 4 (not shown), the insulating layer 34 comprises an array of square lands or of longitudinal strips. In a further modification, Fig. 13 (not shown), the exposed squares 32 of the substrate are covered with an oxidation-inhibiting coating of gold, silver, tungsten, molybdenum, platinum, or nickel to a thickness of about 1000 Š.U., preferably by sputtering. In another modification, Fig. 14 (not shown), the exposed squares and part of the surrounding insulation 34 are coated with the same material as the substrate to provide an increased beam landing area. A different construction (Figs. 15 and 16, not shown) employs a continuous insulating layer over the substrate, and a grid-like conductive layer of metal or semi-conductor material is formed over the insulating layer. This conductive layer may extend over the edge of the insulating layer to the substrate (Fig. 15) or it may be electrically independent of the substrate (Fig. 16). Operation.-The substrate 30 is also the signal plate and is initially held at 20V whilst the insulation 34 is scanned to reduce its potential to zero (Fig. 6, not shown). The plate 30 is then raised to 100V, thereby carrying the insulation 34 up to 80V, and the target is scanned by a modulated beam which produces charged areas varying in potential from 80V to 90V (Fig. 8, not shown). The plate 30 is then reduced to 10V, thereby making the charged areas range in potential from -10V to zero, and the target can be scanned to produce a non-destructive read-out, electrons passing to the exposed areas 32 to a variable extent depending on the charges stored on the surrounding insulation 34. Finally the charge pattern can be erased by raising the potential of plate 30 to 20V and scanning the target.