System and method of integrating a touchscreen within an LCD
First Claim
1. A touchscreen liquid crystal display comprising:
- a liquid crystal display including a viewing surface, a liquid crystal area containing liquid crystal located behind the viewing surface, a plurality of spaced apart elongate first electrodes located on a viewing surface side of the liquid crystal area and a plurality of spaced apart elongate second electrodes located on an opposite side of the liquid crystal area, the first and second electrodes overlapping to form an array of liquid crystal pixel elements, at least some of the first electrodes being displaceable towards the second electrodes in response to external pressure applied to the viewing surface; and
a control circuit connected to the first and second electrodes for controlling the operation of the liquid crystal display and including;
(i) a driver circuit for driving the electrodes for selectively controlling a display state of the pixel elements; and
(ii) a measurement circuit for measuring voltages across at least some of the pixel elements and detecting displacement of the at least some of the first electrodes in response to external pressure applied to the viewing surface based on the measured voltages; and
a reference electrode in the liquid crystal display overlapping with the first or second electrodes to form reference pixel elements, the measurement circuit comprising a comparison circuit for comparing the measured voltages to reference voltages measured from the reference pixel elements, wherein the reference pixel elements are located outside of a viewable area of the liquid crystal display a sufficient distance so as not to be substantially affected by external pressure applied to the viewing surface.
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Accused Products
Abstract
A touchscreen liquid crystal display that includes a liquid crystal display including a viewing surface, a liquid crystal area containing liquid crystal located behind the viewing surface, a plurality of spaced apart elongate first electrodes located on a viewing surface side of the liquid crystal area and a plurality of spaced apart elongate second electrodes located on an opposite side of the liquid crystal area, the first and second electrodes overlapping to form an array of liquid crystal pixel elements, at least some of the first electrodes being displaceable towards the second electrodes in response to external pressure applied to the viewing surface. A control circuit is connected to the first and second electrodes for controlling the operation of the liquid crystal display. The control circuit includes (i) a driver circuit for driving the electrodes for selectively controlling a display state of the pixel elements; and (ii) a measurement circuit for detecting displacement of the at least some of the first electrodes in response to external pressure applied to the viewing surface.
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Citations
19 Claims
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1. A touchscreen liquid crystal display comprising:
- a liquid crystal display including a viewing surface, a liquid crystal area containing liquid crystal located behind the viewing surface, a plurality of spaced apart elongate first electrodes located on a viewing surface side of the liquid crystal area and a plurality of spaced apart elongate second electrodes located on an opposite side of the liquid crystal area, the first and second electrodes overlapping to form an array of liquid crystal pixel elements, at least some of the first electrodes being displaceable towards the second electrodes in response to external pressure applied to the viewing surface; and
a control circuit connected to the first and second electrodes for controlling the operation of the liquid crystal display and including;
(i) a driver circuit for driving the electrodes for selectively controlling a display state of the pixel elements; and
(ii) a measurement circuit for measuring voltages across at least some of the pixel elements and detecting displacement of the at least some of the first electrodes in response to external pressure applied to the viewing surface based on the measured voltages; anda reference electrode in the liquid crystal display overlapping with the first or second electrodes to form reference pixel elements, the measurement circuit comprising a comparison circuit for comparing the measured voltages to reference voltages measured from the reference pixel elements, wherein the reference pixel elements are located outside of a viewable area of the liquid crystal display a sufficient distance so as not to be substantially affected by external pressure applied to the viewing surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 18)
- a liquid crystal display including a viewing surface, a liquid crystal area containing liquid crystal located behind the viewing surface, a plurality of spaced apart elongate first electrodes located on a viewing surface side of the liquid crystal area and a plurality of spaced apart elongate second electrodes located on an opposite side of the liquid crystal area, the first and second electrodes overlapping to form an array of liquid crystal pixel elements, at least some of the first electrodes being displaceable towards the second electrodes in response to external pressure applied to the viewing surface; and
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9. A method for using a liquid crystal display as a user input, the liquid crystal display having a plurality of first electrodes and a plurality of second electrodes located on opposite sides of a liquid crystal containing area, the first electrodes overlapping with the second electrodes and defining an array of liquid crystal display pixel elements, each pixel element being associated with a unique location where an associated one of the first electrodes overlaps with an associated one of the second electrodes, at least some of the first electrodes being displaceable towards the second electrodes when pressure is applied to a viewing surface of the liquid crystal display, the display having a reference electrode overlapping with the plurality of first electrodes or with the plurality of second electrodes to form reference pixel elements that are located outside of a viewable area of the liquid crystal display a sufficient distance so as not to be substantially affected by external pressure applied to the viewing surface, the method including:
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(a) selectively driving the first and second electrodes to cause the pixel elements to display an image visible from a viewing side of the viewing surface; (b) sampling voltages between the first and second electrodes; (c) sampling voltages between the reference electrode and the plurality of first electrodes or second electrodes that the reference electrode overlaps with; and (d) determining based on the sampled voltages if any of the first electrodes have been displaced towards the second electrodes. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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19. A touchscreen liquid crystal display comprising:
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a liquid crystal display including an array of display pixel elements formed by a plurality of parallel first electrodes located on one side of a liquid crystal containing area and overlapping with plurality of parallel second electrodes located on an opposite side of the liquid crystal containing area; a plurality of reference pixel elements formed by a reference electrode extending parallel to the plurality of first electrodes on the one side of the liquid crystal containing area and overlapping with the plurality of second electrodes, the reference pixel elements being located outside of a viewable area of the liquid crystal display a sufficient distance so as not to be substantially affected by external pressure applied to the viewable area through a viewing surface of the liquid crystal display; a driver circuit coupled to the electrodes for driving the electrodes for selectively controlling a display state of the display pixel elements; and a measurement circuit coupled to the electrodes for scanning at least some of the first electrodes by;
measuring display pixel element voltages for at least some of the display pixel elements formed by the first electrode being scanned, and for each display pixel element for which a display pixel element voltage is measured, measuring a corresponding reference pixel element voltage at the reference pixel element that is formed by the reference electrode overlapping with the same second electrode that forms with the first electrode being scanned the display pixel element,the measurement circuit detecting in dependence on the measured display pixel element voltages and the corresponding reference pixel element voltages a relative displacement between at least some of the first electrodes and the second electrodes in response to external pressure applied to the viewing surface.
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Specification