Patent GB-1153542-A (GB)
Title: Improvements in or relating to Alpha-Numeric Display Means
IPC: G09G1/18
Filed: 1967-05-05
Abstract: 1,153,542. Cathode-ray tube displays. BUNKER-RAMO CORP. 5 May, 1967 [6 May, 1966; 27 Feb., 1967], No. 20969/67. Heading H4T. Graphical (e.g. Alpha-Numeric) characters are displayed on the screen on a cathode-ray tube in parallel line format the characters being represented by coded electrical signals which include code elements defining the boundaries of sets of the signals representative of characters to be displayed on a single line of the display. The characters are of two classes, i.e. upper case and lower case and in the described embodiment, which is concerned with displaying stock exchange information, the upper case characters are utilized for stock identification and the lower case for indicating the various transactions. Thus in the display shown in Fig. 2, the upper case letters on the left-hand side identify particular stocks and the lower case numerals and letters indicate the transactions. A maximum of five character positions is considered sufficient for the stock identification characters and the lower case characters indicative of the transactions are displayed on the same line beginning at character position seven. A maximum of twenty characters is allowed per line and where the transaction information (lower case characters) for any one identified stock required more than one line for display such information is carried to the next line (downwards) and indented to position seven. Visual separators (e.g. periods) are employed for separating separate transactions involving an indididual stock and if the signals representative of such periods (considered as lower case characters) are detected at or after position sixteen in any line the period and the subsequent transaction information is displayed on the next line commencing at position seven. Provision is also made for displaying textual messages comprising upper case characters each word of which is separated from the next succeedng word by a period, considered in this case as an upper case character but the appearance of which on the display is the same as the lower case periods. When such a period is detected at or after the fourteenth position it is carried over to the next line and displayed in the first position with the remaining text following it. A maximum of twelve display lines is provided for, the last (twelfth) line being reserved for carry over from the eleventh line and when the twelth line has been written, the first line of the display is erased and a new line subsequently written during which the second line is erased to be subsequently written whilst the third line is erased. Thus the latest line written is identified by the existence of a blank line immediately following it. Each character is represented by an eight-bit code the codes for all characters being fed to a recirculating memory 12 (Fig. 1) incorporating a magnetostrictive delay line and where information is derived from two separate sources, e.g. inputs 1 and 2, for display on separate display devices, multiplexing techniques may be employed. Control apparatus (Figs. 3 and 4, not shown) including logic circuitry operates in response to the coded signals to control the display production in the manner described above the actual characters being formed by selective bright-up of points in a 7 x 5 matrix.