Patent ID: 8259078

Claim:
An integrated liquid crystal display touch screen comprising: a first polarizer; a second polarizer; a first substrate having display control circuitry formed thereon, the first substrate being disposed between the first polarizer and the second polarizer; a second substrate disposed between the first polarizer and the second polarizer and adjacent the first substrate; a liquid crystal layer disposed between the first and second substrates; a plurality of touch sensing elements disposed between the first and second polarizers and not between the first and second substrates, the plurality of touch sensing elements comprising a plurality of touch drive electrodes and a plurality of touch sense electrodes, the plurality of touch drive electrodes and the plurality of touch sense electrodes being operative at least during a touch sensing mode of operation; the plurality of touch drive electrodes and the plurality of touch sense electrodes spaced apart from one another to form capacitive coupling nodes therebetween; a counter electrode used during a liquid crystal display operation and disposed between the liquid crystal layer and the second substrate, the counter electrode separate and distinct from the plurality of touch drive electrodes and separate and distinct from the plurality of touch sense electrodes; the counter electrode being grounded during the touch sensing mode of operation to shield the plurality of touch drive electrodes and the plurality of touch sense electrodes disposed above the counter electrode, from the liquid crystal layer disposed below the counter electrode; the plurality of touch drive electrodes operative to receive a periodic voltage; the plurality of touch drive electrodes driven by the periodic voltage one at a time or in groups; and at least one capacitance sensing circuit operatively coupled to the plurality of touch sense electrodes during the touch sensing mode of operation for measuring a change in current and/or voltage resulting from a change in capacitance at the capacitive coupling nodes.