Driver circuit for electrochromic displays
AssigneeSharp Kabushiki Kaisha
InventorsHiroshi Nakauchi, Yasuhiko Inami, Hisashi Uede, Tomio Wada
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Abstract
A constant-voltage circuit is interposed between a power source and a driver circuit for an electrochromic display. The constant-voltage circuit functions to compensate for variations of an output level of the power source in order to stabilize coloration and bleaching operations. Switching means are interposed between the power source and the constant-voltage circuit for placing the constant-voltage circuit in an operative condition only when the coloration operation or the bleaching operation is conducted.
Claims10
A drive system for an electrochromic display comprising:
- an electrochromic material held between two substrates, a plurality of display pattern segment electrodes and a counter electrode,
- each combination of said display pattern segment electrodes with said counter electrode defining a different desired display pattern;
- a power source delivering a variable current and having an output voltage level subject to variation and a driver circuit means for applying coloration and bleaching voltage signals to said display pattern segment electrodes;
- a constant voltage circuit means connected between said power source and said driver circuit for compensating for variations in said output voltage level of said power source and applying a constant voltage of a fixed level to said driver circuit to stabilize coloration and bleaching operations in said electrochromic display, said constant voltage circuit means including constant current producing transistor means responsive to the variable current delivered by said power source for producing a constant current and converting means connected to said transistor means and responsive to said constant current for producing a constant voltage;
- and
- switching means interposed between said power source and said constant voltage circuit means for placing said constant voltage circuit means in an operative condition only during coloration and bleaching operations.
A drive circuit for an electrochromic display comprising:
- a power source delivering a variable current and having a voltage level output subject to variation;
- a driver circuit means for developing coloration and bleaching voltage signals to be applied to said electrochromic display;
- a constant voltage circuit means interposed between said power source and said driver circuit means for compensating for variations in a said output voltage level of said power source and applying a constant voltage of a fixed level to said driver circuit to stabilize the coloration and bleaching operation of said display, said constant voltage circuit means including constant current element means connected to said power source and responsive to said variable current delivered by said power source for providing a constant current and converting means responsive to said constant current for converting said constant current into a constant voltage;
- and
- switching means interposed between said power source and said constant voltage circuit means for placing said constant voltage circuit in an operative condition only during said coloration and bleaching operation and for producing first and second polarities, respectively, of said constant voltage to conduct said coloration and bleaching operations, respectively, in said electrochromic display.
Dependencies are inferred from the claim text.