Electroluminescent device for temporary information storage

An dectroluminescent element becomes polarized when it is pulsed with a direct voltage. That is, it has a memory of the pulse polarity. If the element is later pulsed with a voltage of the same polarity, it emits a flash of light. If instead the later pulse is of opposite polarity, then the light flash is substantially brighter. The polarization has a decay time up to several seconds. This capability of memorization and interrogation suggests that an electroluminescent element can be used for the temporary storage of information. To store a binary 1, the element is supplied with a write pulse of negative polarity. Interrogation is accomplished with a positive read pulse, and a gated photomultiplier responds to the light output. To store a 0, no negative pulse is supplied. Fast-decay electroluminescent phosphors were evaluated for memory device application. A particular phosphor gave a signal-to-noise ratio of 8 for a storage time of 20 millisec. and 10 for a storage time of 2 millisec. The readout time was 2 microsec. Experiments indicate that high storage density can be obtained in a crossed-grid electroluminescent pand having a non-linear resistance layer to eliminate crosstalk.