| 摘要 |
821,637. Magnetic information storage apparatus. INTERNATIONAL BUSINESS MACHINES CORPORATION. May 7, 1956 [May 10, 1955], No. 14026/56. Class 40 (9). [Also in Group XXXVI] A magnetic matrix store comprises toriodal ferrite cores which are located in annular recesses in an insulated plate and have associated circuits formed by a photo-printing operation. As shown in Figs. 1 and 2, the cores 10 are associated in the usual manner with read and write windings X1-X4, Y1-Y4 in columns and rows and with an inhibit winding z which permits parallel operation with similar stores. Alternative wiring arrangements of a sense winding S to improve the signal to noise ratio are shown. The insulated plate 20 consists of a photo-sensitive glass or moulded plastic, the annular core recesses 30, Figs. 4a, 4b, and holes 32 for the printed conductors being formed by etching with hydrofluoric acid after the plate is subjected to ultra-violet light through a negative hole pattern. It is stated that the portions of glass exposed to ultra-violet light etches away at a considerably higher rate. The toroids are fitted in the recesses by shaking the plate and are secured by an overall covering of paraffin wax. The assembly is then oxidized by dipping in chromic acid, followed by washing in water, to permit the application of a precipitated silver coating. A film of photo-resist such as an aqueous solution of gelatin or polyvinyl alcohol to which potassium dichromate is added is next applied to the silver coating, and the assembly is exposed to ultra-violet light through photo-positives of the circuit pattern positioned on each side of the plate. Subsequently, the plate is washed in water to remove the unfixed photo-resist which covers the regions where circuitry is required. The exposed regions, which include the inside walls of the holes 32, are thickened by copper plating to which a top flash of gold may be applied. The harder fixed photo-resist material is then removed by further washing and the background of silver exposed is removed by a quick wash in dilute nitric acid. The process is then complete and after further cleaning in water the assembly may be protected by a wax or lacquer coating. A number of completed matrix stores may be stacked by the use of rods 40 and spacers 41 as shown in Fig. 5 to form a parallel-access array; links being fitted between terminus holes 35. Specification 784,549 is referred to. |
