Addressing device and method for rapid video response in a bistable liquid crystal display
First Claim
1. A method for modifying a liquid crystal display comprised of an array of pixels arranged in a plurality of rows and a plurality of columns, said pixels have a first optical state and a second optical state, both optical states stable in the absence of an electric field, wherein control signals are applied to the array of pixels to modify the optical state thereof, said method comprising:
- simultaneously applying selective control signals to the plurality of rows having pixels requiting a change to the first optical state; and
sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state.
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Accused Products
Abstract
A front-lit, non-gray scale liquid crystal display device (10) including a polymer stabilized cholesteric liquid crystalline material has two optical states stable in the absence of an electric field. In a reflecting optical state incident illumination is directly reflected by the liquid crystal, producing a light pixel. In a scattering optical state incident illumination is absorbed by a black surface on the rear of the display, producing a dark pixel. A method employing a plurality of display control signals having the same polarity and differing phase relationships permits the fast video response of the display, notwithstanding that the average time to switch from a scattering optical state to a reflecting optical state is about 30 milliseconds, requiring about fifteen seconds to update a typical 480-row liquid crystal display using conventional array sequencing techniques. Several routines are presented for determining when to update such a display for a variety of applications.
58 Citations
37 Claims
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1. A method for modifying a liquid crystal display comprised of an array of pixels arranged in a plurality of rows and a plurality of columns, said pixels have a first optical state and a second optical state, both optical states stable in the absence of an electric field, wherein control signals are applied to the array of pixels to modify the optical state thereof, said method comprising:
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simultaneously applying selective control signals to the plurality of rows having pixels requiting a change to the first optical state; and sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A display device comprising:
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display means including an array of pixels arranged in a plurality of rows and a plurality of columns, said pixels have a first optical state and a second optical state, both optical states stable in the absence of an electric field; and control means for generating a plurality of control signals for application to the array of pixels to modify the optical state thereof, said control means simultaneously applying selective control signals to the plurality of rows having pixels requiting a change to the first optical state, and thereafter sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for modifying a liquid crystal display comprised of an array of pixels arranged in a plurality of rows and a plurality of colas, said pixels have a first optical state and a second optical state, both optical states stable in the absence of an electric field, wherein control signals are applied to the array of pixels to modify the optical state thereof, said method comprising:
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determining a number of rows having pixels requiring a change in optical state; and determining whether the number of rows has reached a threshold value, wherein; (a) if the number of rows has not reached the threshold value, sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state, and (b) if the number of rows has reached the threshold value, simultaneously applying selective control signals to the plurality of rows having pixels requiring a change to the first optical state, and thereafter sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state. - View Dependent Claims (23, 24, 25, 26)
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27. A display device comprising:
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display means including an array of pixels arranged in a plurality of rows and a plurality of columns, said pixels have a first optical state and a second optical state, both optical states stable in the absence of an electric field; means for determining a number of rows having pixels requiring a change in optical state; means for determining whether the number of rows has reached a threshold value; and control means for generating a plurality of control signals for application to the array of pixels to modify the optical state thereof, wherein; (a) if the number of rows has not reached the threshold value, sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state, and (b) if the number of rows has reached the threshold value, simultaneously applying selective control signals to the plurality of rows having pixels requiting a change to the first optical state, and thereafter sequentially applying selective control signals to one or more rows of pixels having at least one pixel requiring a change in optical state. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification