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US 4,286,266 AGranted
Display device
AssigneeU.S. Philips Corporation
InventorsMaarten De Zwart, Johannes L. A. M. Heldens
Life of this patent
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Abstract
In a liquid crystal display device which upon controlling with direct voltage shows a memory effect that can be erased by alternating voltage, the written area can expand beyond the edge of the electrode so that edge zones can no longer be erased readily. This disadvantage is avoided by covering the edges of the electrodes with an insulating layer.
Claims3
A display device comprising at least two supporting plates;
- a plurality of control electrodes formed in a pattern on at least one of said supporting plates, said control electrodes being individually energized, a counter electrode formed on the other of said supporting plates;
- a layer of liquid crystal disposed between said supporting plates and in direct contact with said electrodes;
- a semi-permanent visible disturbance being induced in said liquid crystal by means of direct voltage and being erased by means of alternating voltage;
- and insulating means for covering at least the edges of said control electrodes said remaining surfaces of said electrodes remaining in direct contact with said liquid crystal.
1 more element
Dependencies are inferred from the claim text.