| 摘要 |
A randomly accessible memory display is disclosed wherein a latching memory panel can be placed in direct optical contact with the triggering electroluminescent panel having a similar matrix. Once the glowing light from the trigger panel shines on the photosensitive resistive layer providing positive feedback, the corresponding region in the latching memory panel is latched. In accordance with the invention, a technique is disclosed for electrically reading the latched state in any one cell. This is done by selectively propagating a high frequency sinusoidal interrogation signal through each of the Y axis lines connected to the cells and measuring any phase alteration in each of the X axis lines connected to the cells, for each Y axis line interrogated. Since the resistance of the photosensitive resistor for a particular latching cell is altered if that cell is emitting light, the impedance of the cell is changed, thereby introducing a phase shift to the interrogation signal. The detection of the phase shift indicates whether the selected cell is latched in its light-emitting or light-extinguished state.
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