摘要 |
A liquid crystal display (LCD) device ( 100 ) having an integrated touchscreen includes a built-in probe signal source behind the liquid crystal (LC) layer ( 20 ). The probe signal source may include a pair of light sources ( 82 and 84 ) modulated at first and second frequencies (f 1 and f 2 ), respectively. A pair of probe light sensing devices ( 92 and 94 ) may also be implemented behind the LC layer, each configured to measure the intensities of the first and second frequencies, respectively. The probe light sensing devices are designed to detect user contact with the touchscreen surface by sensing a reflection of the probe light signals from the touchscreen surface. Using the multiple intensity measurements from each probe light sensing device, the location of the point of contact on the touchscreen surface is determined.
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