GB743947A - Optical scanning of record bearing member - Google Patents

Abstract

743,947. Photo-electric devices. INTERNATIONAL BUSINESS MACHINES CORPORATION. Sept. 30, 1953 [Oct. 3, 1952], No. 26834/53. Class 37. [Also in Groups XIX and XL (b)] A photo-electric cell for use in a record sensing device is of a size comparable with that of the characters on the record. A light-sensitive crystal may be used and such a crystal may be formed as laminae 1.5 mm. wide, 2 mm. high and having a thickness of 0.3 mm. The light-sensitive element may be sulphides selenides and tellurides of lead, thallium and cadmium. Such an arrangement is shown in Fig. 6 where a thin semi-conductive layer 13 is applied to an insulating base 12 for example of glass or quartz, supply electrodes 14, 15 being mounted at opposite ends. A semi-conductor element consisting of for example selenium or cuprous oxide may be arranged on an electrically conducting base plate, the layer being covered by a thin electrically conducting layer. A further arrangement is shown in Fig. 7 in which a disc-shaped body 17 consists of a semi-conductor (e.g. zirconium or silicon) with a spherical indentation in which a point contact 19 is mounted. The other contact 20 is arranged on the peripheral surface of the disc.