BISTABLE EL PANEL STUDY.
Final rept. 13 Oct 64-30 Jun 66,
SYLVANIA ELECTRONIC SYSTEMS-EAST NEEDHAM MASS
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The study was performed to determine the most feasible method to incorporate semiconductor integrated circuits into an electroluminescent display panel to control the EL lamps and to provide memory. A basic circuit was developed that consists of a high voltage, silicon-controlled rectifier SCR to control the EL lamp, and a low-voltage SCR to provide the memory. The memory circuit can be turned ON or OFF by application of coincident X and Y selection pulses of the proper polarity thus, many such circuits can be connected in a rectangular matrix to facilitate addressing the elements in a large panel. The performance objectives for this study included an ON brightness of 20 foot lamberts, a contrast ratio of at least 201 between ON and OFF elements, resolution of at least 8 elements per inch, and the capability for expansion to a large-area display consisting of 1,000,000 elements. Specific studies were conducted to determine the suitability of oxide-isolation techniques to provide circuit isolation, and it was determined that this method, while feasible, would be more costly than other available methods, such as beam-leading. A technique was developed that allows electrical contacts to be soldered directly to the rear electrode of an electroluminescent lamp. A high-voltage, low-leakage SCR less than 3 microamperes RMS at 250 volts RMS was designed and used successfully in a breadboard-model display consisting of one-hundred elements. Author
- Electrical and Electronic Equipment
- Electricity and Magnetism