Patent ID: 8243027
Filing Date: 2012-08-14
Classification: G02F,G06F

Abstract:
1. A touch screen comprising a liquid crystal display with integral touch sensing, the 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 pixel electrodes disposed on the first substrate; a plurality of touch drive electrodes disposed between the liquid crystal layer and the second substrates and extending in a first direction, the plurality of touch drive electrodes providing a driving voltage waveform during a touch sensing mode of operation; a plurality of touch sense electrodes disposed between the liquid crystal layer and the second substrates and extending in a second direction, transverse to the first direction; a counter electrode disposed between the liquid crystal layer and the second substrate, wherein the counter electrode is segmented and comprises one of the plurality of touch drive electrodes or the plurality of touch sense electrodes; the plurality of touch drive electrodes and the plurality of touch sense electrodes being operative during the touch sensing mode of operation, the counter electrode operative to provide a common voltage waveform, different from the driving voltage waveform, during a display mode of operation; the plurality of touch drive electrodes and the plurality of touch sense electrodes being spaced apart from one another to form capacitive coupling nodes therebetween; 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.