Liquid crystal display device employing a guard plane between a layer for measuring touch position and common electrode layer
First Claim
1. In a liquid crystal display having a plurality of cells each comprising a first substrate having a common electrode integrated thereon, a second substrate having a pixel electrode integrated thereon, liquid crystal material disposed between said common electrode and said pixel electrode, a device for determining contact position of a touch input device with said first substrate comprising:
- a signal layer and guard plane layer integrated into said first substrate and disposed between said first substrate and said common electrode, the signal layer being capacitively coupled to the common electrode, and the guard layer being disposed between the signal layer and the common electrode;
a first signal generator for applying a first signal to said signal layer;
a second signal generator for applying a second signal to said guard plane layer to thereby lower capacitive coupling of noise between said signal layer and said common electrode; and
position determining means for determining contact position of said touch input based upon response to said first signal.
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Accused Products
Abstract
The present invention provides for touch input functionality in a liquid crystal display having a plurality of cells each comprising a first substrate having a common electrode integrated thereon, a second substrate having a pixel electrode integrated thereon, and liquid crystal material disposed between the common electrode and pixel electrode. A first conductive layer (signal layer) and second conductive layer (guard plane layer) are integrated onto the first substrate and disposed between the first substrate and the common electrode. Contact position of a touch input device with the first substrate is determined by applying a first signal to the signal layer. A second signal is applied to the guard plane layer to thereby lower capacitive coupling between the signal layer and the common electrode. The second signal may be generated by scaling amplitude and/or phase shifting the first signal. Response to the first signal is measured to determine contact position of the touch input device. Preferably, the portion of the signal layer disposed opposite the pixel electrode is a patterned layer of black matrix material, and the guard plane layer may be a transparent ITO layer. Alternatively, portions of the signal layer and guard plane layer disposed opposite the pixel electrode may be a patterned layer of black matrix material. A resistor network may be coupled to the signal layer to linearize resistance of the signal layer in a horizontal and vertical direction. By lowering the capacitive coupling between the signal layer and the common electrode, the guard plane layer and signal applied thereto enables the determination of contact position of a portion of the human body (such as a finger or a toe) based upon the measured response to the source signal. The present invention may be in display systems wherein a matrix of display elements are viewed from above a first side of a substrate and the display elements are disposed on the second side (i.e., the opposite side) of the substrate.
190 Citations
34 Claims
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1. In a liquid crystal display having a plurality of cells each comprising a first substrate having a common electrode integrated thereon, a second substrate having a pixel electrode integrated thereon, liquid crystal material disposed between said common electrode and said pixel electrode, a device for determining contact position of a touch input device with said first substrate comprising:
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a signal layer and guard plane layer integrated into said first substrate and disposed between said first substrate and said common electrode, the signal layer being capacitively coupled to the common electrode, and the guard layer being disposed between the signal layer and the common electrode;
a first signal generator for applying a first signal to said signal layer;
a second signal generator for applying a second signal to said guard plane layer to thereby lower capacitive coupling of noise between said signal layer and said common electrode; and
position determining means for determining contact position of said touch input based upon response to said first signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. In a liquid crystal display having a plurality of cells each comprising a first substrate having a common electrode integrated thereon, a second substrate having a pixel electrode integrated thereon, liquid crystal material disposed between said common electrode and said pixel electrode, a method for determining position of contact of a touch input device with said first substrate comprising:
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providing a signal layer and guard plane layer integrated into said first substrate and disposed between said first substrate and said common electrode, the signal layer being capacitively coupled to the common electrode and the guard layer being disposed between the signal layer and the common electrode;
applying a first signal to said signal layer;
applying a second signal to said guard plane layer to thereby lower capacitive coupling of noise between said signal layer and said common electrode; and
measuring response to said first signal to determine position of said touch input. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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Specification