Patent GB-1337589-A (GB)
IPC: G06V30/194
Filed: 1971-11-29
Abstract: 1337589 Pattern recognition systems; readonly stores NATIONAL RESEARCH DEVELOPMENT CORP 29 Nov 1971 [4 Sept 1970 17 Dec 1970] 42488/70 and 59988/70 Headings G4A and G4R A read-only store comprises insulating material supporting a number of first conductors, a number of second conductors, and a number of resistive links linking the first and second conductors. Each link includes a film of electrically conductive material deposited on the insulating material and is of such dimensions and resistance that the application of a voltage V between associated first and second conductors causes the link to be fused over an annular area surrounding the first conductor, whereas application of a voltage V/2 does not cause fusing. Fig. 2 illustrates one cell of a matrix store in which the fusible film 15 is supported on insulator 13 and is connected to conductive discs 14, 17. Disc 17 carries a disc 18 and a ring 19 of resistive or semi-conductive material, the disc 18 being connected to a row conductor 21 and the ring 19 to a column conductor 20. Film 15 is earthed. When appropriate voltages are applied to conductors 20, 21 an annular area of film surrounding disc 17 is fused. Read out is by way of disc 16, a potential appearing on disc 16 of a selected cell only if the film surrounding it has been fused. In another arrangement, Fig. 7, disc-like conductors 26 penetrate the insulating substrate. Conductors 26 are joined to conductors 24 by annular or spiral fusible films 27. At least part of the film is fused, as shown at the left of Fig. 12, when sufficient current is passed between selected conductors 26, 24. A number of these stores may be stacked as in Fig. 8. The first conductors 50, Fig. 11, may be formed on one side of an insulating substrate 54 and the second conductors 52 on the other side. The substrate is formed with holes 55 whose walls are coated with a conductive material 56 joining the second conductors to the fusible annular film 58. Fig. 13 shows a substrate 64 carrying studs 66, connected to a common input conductor, and output conductors 62, 63 connected to the studs by fusible films 67. Insulating material 68 is provided as shown. The stacked stores shown in Fig. 8 may be used in a pattern recognition system. When a bit is to be written in to a particular point in the stack of stores the appropriate column of studs 26 is selected by closing a switch S1 and the appropriate memory plane by closing a switch S2 to earth. A voltage kx m  is applied via the closed S 1 to fuse the film about the relevant stud. For example, if the store is required to give an output Î 0À1 when input signal x 1 = 0 and x 2 = x m  then the films about the studs in the lowest plane that are connected to - x 2 and + x1 must be fused. Data is recorded in each plane in a similar manner. During read out, all switches S1 are closed and switches S2 are connected to their respective operational amplifier inputs. Read voltages + x m  and -x m  representing the pattern to be recognized are then applied to the columns of studs, and the x memory plane containing the closest pattern then gives the largest output. In an alternative system each amplifier 34, Fig. 8, is a differential amplifier receiving inputs from a pair of planes, corresponding films in the planes of a pair being fused and intact, respectively.