Patent GB-819582-A (GB)
Title: Record comparing reader
IPC: G06F7/02
Filed: 1956-02-01
Abstract: 819,582. Photo-electric reading and comparing arrangements. INTERNATIONAL BUSINESS MACHINES CORPORATION. Feb. 1, 1956 [Feb. 4, 1955], No. 3170/56. Class 40 (3). [Also in Group XIX] Apparatus for comparing data read from two moving records comprises optical means for simultaneously producing relativley stationary images of the records on the same light-sensitive target and means for scanning the images with an electron beam to produce output signals dependent on the agreement or otherwise between the stored data. In a first embodiment data record cards 10 are passed from a store 11 through two inspection positions to a hopper 14. Card 10b is shown in the first position where it is backed by a light-absorbing plate 15 and illumination of lamp 21 results in an image of the card by reflection being formed on the image screen of light storage electron discharge tube 24. Thus data holes punched in card 10b will appear dark on a light background in the image formed on the tube screen. The card 10a in the second position can be illuminated from behind by lamp 17 to form an image on the screen of tube 24 superposed exactly over the image of card 10b. The data holes, however, in the card 10a appear bright on a dark background. The card drive mechanism is coupled to synchronizing circuit 34a which flashes the lights 17 and 21 when a pair of cards are correctly positioned, so forming the images in a substantially stationary manner on the storage screen of the tube. The circuit 34a also controls the scanning deflection circuits 38 for the electron beam in the tube. The signal output from the tube is amplified and fed to comparison circuit 47. This circuit gives an output on line 50 for the normal illumination level which occurs also when a dark spot from card 10b coincides with a bright spot from card 10a. A dark spot, due to a hole in card 10b occurring without a corresponding hole in card 10a, gives an output on line 52 whilst a bright spot due to a card 10a hole occurring without a corresponding hole in card 10b gives an output on line 51. The outputs on the lines 50, 51 and 52 may be used in conjunction with information about the position on the card being scanned derived from the sweep circuits. In another embodiment light is directed through both cards being compared and the images of the hole patterns produced are displaced relative to each other by the width of a single hole image in the direction of scan on the screen of the light storage tube. Thus the existence of corresponding holes produces two bright spots one following the other whilst a hole in one card but not in the other gives only a single bright spot on the screen. By the use of a synchronized switch in the tube output, signals derived from the positions where a first spot may occur are directed through a delay means so as to be available for comparison with signals from the second spot position to give one of three outputs as before (Figs. 3 and 4, not shown). The use of a second light storage electron discharge tube, on the screen of which the image of one of the cards is focused, for providing an electrical output corresponding to the data concerned is described in this embodiment. The second tube is scanned in synchronism with the first. Specifications 680,892 and 815,487 are referred to.