Patent GB-1332240-A (GB)
Title: Data input device
IPC: G06F3/023
Filed: 1971-01-19
Abstract: 1332240 Cathode-ray tube displays ING C OLIVETTI & C SpA 19 Jan 1971 [21 Jan 1970] 2625/71 Heading H4T A data input device comprises a CRT 1 (Fig. 1) whose screen is divided into two parts of which the upper visually displays a message while the lower acts as keyboard data input. Apertures 3 are formed in a layer 4 overlying the screen to expose the screen directly (Fig. 2, not shown) or through a transparent key (Fig. 3, not shown); an optical fibre 7 leading from each aperture through layer 4 to a photodetector (Fig. 4). An electron beam scans the screen lineally and in correspondence is modulated to display an alphanumeric symbol coded to be characteristic of the corresponding zone. Each scan line is subdivided into points 9 which are combined spatially to form a corresponding character over 7 adjacent lines for each zone (Fig. 5). Line counter 10, zone counter 11, and final point counter 12 (Fig. 6) are synchronized with the screenscan deflection unit 13 during traverse of the keyboard part; the zonal counter registering 1 when the beam is in the 1st zone, et. seq, while supplying a signal CZ1 to command 5 Î 7 core matrix character generator 16 controlled from unit 14 over conductors corresponding to the several keyboard zonal characters, which activate the relevant control wire on command to energize to "1" state the cores designating character 1, et. seq. Line counter 10 excites the first row of the matrix after 100 scan lines with command C101, and succeeding rows up to the 7th on commands C102-C107 corresponding to successive 100 line counts. During energization of the lst row, the 5 columns of the matrix are energized in succession by the point count from 4 to 8, and the cores are reset where intersecting row and column currents coincide, and the columnar outputs are fed as OR functions to grid control unit 13 for beam intensity, to develop an illuminated point corresponding to character in the first line, in the first zone. As the beam scans lines 101 to 107, the succeeding zonal characters determinized by the core matrix wiring appear as a bright display and are persistently visible in the zonal apertures with reduced intensity. On scanning of successive points, light passes to the photodetector to produce a pulse for given intensity excitation, which is disabled by insertion of a finger in the aperture or depression of the key. Inverted photodetector signals enter AND gates 90-94 &c. corresponding to the number of zonal keys, which receive clock signals, a zonal signal from counter 11, and the delayed core matrix output so as to produce output pulse when a point forming the character of a zone is obscured and no light is received by the photodetector. The AND gates are connected to counters 110 to 114 &c. for the points of the zonal counters which are obscured and operate if a majority of the points defining the character are obscured, to enter the relevant character. The counter outputs then set flip-flop FF which enables AND gate 200 receiving signal 120, the logical sum of the signals from keyboard zonal AND gates 130 to 134, which receive respectively signals A to E from counters 110 to 114 and signals C21 to C25 from zonal counters 11. The signal X from AND gate 200 is present only for the zonal period of the registered key, and enables AND gate 201 to supply core matrix output to grid control unit 202 to bright up the electron beam to denote entry of the character designated. The upper part of the CRT screen displays an input message visually, which may be derived from keyboard entry, or from a logic store enabled by a keyboard code. Zone counter 11 also energizes (Fig. 7) coder unit 17 generating 2 codes for each zone; one corresponding to characters for visual display and one addressing store 19 containing messages. Thus on operation of an address code key, AND gate 18 is enabled to readout the store for information transfers to write unit 21; which feeds into a delay line buffer store 22 with capacity for a block of characters sufficient to fill the 1st part of the display screen. On operation of a visual display key, unit 17 feeds enabled AND gate to transfer the character code into store 22 over write unit 21. Store 22 is read out by unit 23 in sync. with scanning of the first part of the screen, to feed control 14 of character generator matrix 16, which in turn is read by control unit 24; which may embody counters 10, 11, 12. In modifications, the store 19 may be embodied in a control computer of which the invention is the read out, snd the keyboard may be modified for different character display by interchange of cover layer 4 for one having a differing key arrangement. The characters to be displayed may be derived by programming a store, and the light emitted from the key zones may be conducted to the photodetector over a uniform transparent photoconductive layer.