Thin Film Display Switches.
Final rept. 1 Apr-12 Dec 74,
WESTINGHOUSE RESEARCH LABS PITTSBURGH PA
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A thin film transistor with a floating second gate, capable of nonvolatile storage of analog data, was the subject of the investigation. Further development resulted in a closely controlled, reproducible fabriacation process and a higher voltage capability. A 40x40 element, 1 inch square matrix, consisting of X-Y addressible memory transistors at each point was designed, laid out using CAD techniques and fabricated in a single vacuum deposition cycle. Mask and substrate registration techniques were also improved, resulting an excellent run-to-run reproducibility of the deposition patterns. By coating the finished memory matrices with an electroluminescent phosphor Westinghouse hypermaintenance phosphor, providing a common transparent front electrode and sealing with a cover-glass, complete 40 x 40 element storage displays were made. The displays were operable up to 140V peak-to-peak. The EL driving frequencies ranged from 3 to 20 kHz. Writing of information into individual elements was demonstrated by manual pulsing of rows and columns. Letters were written into the panel in this manner, and the non-volatile storage of such patterns over periods of excess of 90 minutes was demonstrated.
- Electrical and Electronic Equipment
- Computer Hardware