Patent GB-936967-A (GB)
Title: System for large-area display of pictorial and alpha-numeric information
IPC: H04N3/30
Filed: 1961-03-10
Abstract: 936,967. Visual display systems. STANDARD TELEPHONES & CABLES Ltd. March 10, 1961 [March 28, 1960], No. 8856/61. Class 40 (3). The invention relates to a visual display system for producing a large area display of alphanumeric or graphical and pictorial information and in its broadest aspect comprises a receiver/ converter in which the input information is decoded (if necessary) and converted (by a monoscope tube if alpha numeric and a television camera if pictorial) into an electric signal which, because of the difference between the input rate and the printing rate, is stored before being transformed into a visual display. The display means, which characterize the invention, comprises a dielectric sheet which is moved over a plurality of sequentially switched zerographic electrodes (Fig. 1, not shown) arranged in a row across and perpendicular to the motion of the sheet. In one form of the invention (Fig. 2) illustrating its application to alpha-numeric information, the input information in pulse code form, that is from a computer or teletype machine, is interrogated by the identifying circuit 32 which separates the signal information from the positional information. The signal information from the character selector circuit 46 is applied to the monoscope tube 34 which is of a known type and in which the target 36 comprises a plurality of characters written in printers' ink on an aluminium plate. The video output developed across the resistor 50 is amplified and applied to the storage tube 54 through the switch 56 which controls " writein," " read-out," " prime " and " erase " within the tube 54. The information is stored in sequence on the storage electrode 58 until required for " read-out." After " read-out " the information is visually displayed on the endless belt 114 of dielectric polyester material. The belt 114 is driven by the motor 86 in synchronism with the vertical scanning of the storage electrode 58. Writing heads 116, 216 positioned on opposite sides of the belt 114 and extending transversely thereto are sequentially actuated by the switch 92 (Fig. 3, not shown) through the video amplifier 90 and in synchronism with the horizontal scanning of the electrode 58. The switch 92 (Fig. 3, not shown) which includes a pulse counter, switching matrix and modulated pulse amplifiers, sequentially samples the output signal from the storage electrode 58 at discrete intervals and energizes the, respective dot-forming elements of the writing heads 116. The monoscope tube 34 and the storage tube 54 may be combined into a single unit (Fig. 5, not shown). If the information to be displayed is graphical in character the monoscope tube is replaced by a conventional television camera (Fig. 6, not shown) and the storage tube 54 may be eliminated by the use of a slow scan television camera (Fig. 7, not shown). Visual displays embodying the invention but utilizing magnetic recording or electrolytic recording are referred to. A " colour " display in which the information is written into the storage tube at different levels is also disclosed.