Passive matrix display with bistable electro-wetting cells
First Claim
1. A display unit comprising at least one electro-wetting pixel, each electro-wetting pixel comprising:
- a closed cell;
a polar liquid and a non-polar liquid, said liquids being immiscible, having different optical properties and being contained in said cell;
a counter electrode; and
at least one electrode pair, each electrode pair comprising an address electrode and a retain electrode, said address and retain electrodes being separated from said liquids by a surface that is lyophobic in relation to only one of said liquids; and
wherein said address and retain electrodes are arranged at respective electric potentials to control a spatial distribution of said liquids and thereby defining a multi-stable pixel state, andwherein a current state is retained by applying a potential to the retain electrode in relation to the counter electrode and removing any potential from the address electrode in relation to the counter electrode.
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Accused Products
Abstract
A display unit comprising electro-wetting pixels (1300) is provided. The inventive pixels (1300) provide bistable or multi-stable pixel states and thus facilitates passive matrix addressing. For this purpose an additional electrode (1305) is arranged for each multi-stable state. Consequently, each pixel comprises one counter electrode (1306) and at least one pair of address and retain electrodes (1304, 1305). In order to activate a pixel, an address potential is applied to the address and retain electrodes (1304, 1305) in relation to the counter electrode (1306), and in order to deactivate a pixel the potential is removed. In order to retain a current pixel state a retain potential is applied to only the retain electrode (1305) in relation to the counter electrode (1306); the current pixel state, be it active or passive, will then be preserved and the retain potential configuration thus provides a bistable pixel state.
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Citations
14 Claims
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1. A display unit comprising at least one electro-wetting pixel, each electro-wetting pixel comprising:
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a closed cell; a polar liquid and a non-polar liquid, said liquids being immiscible, having different optical properties and being contained in said cell; a counter electrode; and at least one electrode pair, each electrode pair comprising an address electrode and a retain electrode, said address and retain electrodes being separated from said liquids by a surface that is lyophobic in relation to only one of said liquids; and wherein said address and retain electrodes are arranged at respective electric potentials to control a spatial distribution of said liquids and thereby defining a multi-stable pixel state, and wherein a current state is retained by applying a potential to the retain electrode in relation to the counter electrode and removing any potential from the address electrode in relation to the counter electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for bistable addressing of at least one electro-wetting pixel, each pixel comprising an address electrode, a retain electrode and a counter electrode,
in which an active state is set by applying a potential to the address electrode and the retain electrode in relation to the counter electrode; - and
in which a passive state is set by removing any potential from the address electrode and from the retain electrode in relation to the counter electrode;
the method further comprising the step ofretaining a current state by applying a potential to the retain electrode in relation to the counter electrode and removing any potential from the address electrode in relation to the counter electrode. - View Dependent Claims (13, 14)
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Specification