| 摘要 |
1,274,639. Matrix displays. INTERNATIONAL BUSINESS MACHINES CORP. 9 April, 1970 [26 May, 1969], No. 16830/70. Heading G5C. A display apparatus incorporating a gas discharge panel of the type having a first and second plurality of conductors spaced apart and arranged to form a matrix of cross-points includes first means 12 for applying a sustaining voltage to the conductors, the sustaining voltage being insufficient to excite a discharge but sufficient to maintain a discharge at a crosspoint, and second means 14 for establishing an electrical discharge externally of the panel adjacent to a selected cross-point to excite a discharge thereat. A sinusoidal sustaining voltage A is applied by generator 12 to the panel 10 and to a differentiating circuit 20 which applies a spiked waveform B to clipping circuits 22 and 24 to produce waveforms C and D of positive and negative spikes. The negative spikes are converted to positive spikes by an inverter 26. The two sets of positive spikes together with voltage from a source 16 are applied to AND circuits 28 and 30 respectively which are connected to respective gate circuits in the stylus 14 controlled by "write" and "erase" buttons 32 or 34. Waveform E indicates the manner in which positive spikes superimposed on the sustaining voltage by applying the stylus 14 to the panel produce write and erase voltages which occur on the positive and negative peaks respectively of the sustaining voltage. It is also possible to provide a stylus which produces a positive write voltage and a negative erase voltage both of which operate on the positive peaks of the sustaining voltage. A further alternative form of stylus (Fig. 3, not shown) has a single on-off button and has in its tip a photodiode which is shielded during the writing operation and is illuminated by light from the display panel to act as a switch when erasure is required. In a more sophisticated circuit (Fig. 4, not shown) the sustaining generator 12 is connected to the individual X and Y conductors of the panel through X and Y pulsers which are connected through an address logic circuit to a computer. The X and Y conductors are also connected to sensing circuits to feed information back to the computer. |
