GB1302506A - - Google Patents

Abstract

1302506 Cathode-ray tube displays ISE ELECTRONICS CORP 14 July 1971 [16 July 1970] 32920/71 Heading H4T Patterns, e.g., alpha-numeric characters, are displayed on a cathode-ray tube 12 (Fig. 1) by selective control of an apertured matrix electrode 12c, 12d positioned in the electron stream from the cathode 12a and may be selectively enlarged or reduced by controlling the voltages on the focusing electrode 12f and the grid electrode 12e uniformity of display brightness being maintained when the size is changed by controlling the voltage on the first grid electrode 12b. The position of each character is determined by stepped voltage waveforms supplied to the deflection windings 12g and the spacing between adjacent characters and between successive lines of characters is varied in accordance with the change in character size to prevent overlapping (Fig. 7). The system is controlled by signals from, (e.g. a computer) memory 1 the decoded output of which selects a particular pattern memory 4 such as the diode matrix 4 (Fig. 2) concerned in the display of the numeral "2" (Fig. 3) and also provides the various electrode voltages for the tube 12 to effect the controls referred to above. The diode matrix 4 is connected to the beam controlling aperture matrix electrodes 12c, 12d as shown at 14 (Fig. 2) and "scanned" by successive pulses from counter 5 applied to inputs 17-21 to provide the condition required to allow the electron stream to pass through the appropriate intersections of the X and Y elements of the matrix which are required to produce the display, in this case the numeral "2". The D/A converters 7, 8 and 9 may be replaced by circuits which produce the required electrode voltages by including a single D/A converter in the common input from decoder 3 (Fig. 8, not shown). The whole system is controlled by clock pulse generator 6.