Patent ID: 8803155

Claim:
A thin-film transistor (TFT) sensor, comprising: a bottom gate electrode on a substrate; an insulation layer on the bottom gate electrode; an active layer in a donut shape on the insulation layer, the active layer including a first channel and a second channel through which current generated by a charged body flows and including a hole for separation of the first channel and the second channel; an etch stop layer on the active layer, the etch stop layer including a first contact hole and a second contact hole, and including a middle portion that overlaps the hole for separation of the first channel and the second channel; a source electrode and a drain electrode burying the first contact hole and the second contact holes, the source electrode and the drain electrodes being symmetrically disposed on a pair of first opposite regions of the middle portion of the etch stop layer so as to face each other; a first top gate electrode and a second top gate electrode that are symmetrically disposed on a pair of second opposite regions of the middle portion of the etch stop layer so as to face each other, the first top gate electrode and the second top gate electrode being spaced apart from each other and controlling flow of the current through the first channel and the second channels, respectively, wherein each of the first opposite regions does not overlap with each of the second opposite regions; and wherein changes in amounts of the currents flowing in the first channel and the second channels occur based on movement of the charged body relative to the first top gate electrode and the second top gate electrodes, and correspond to a touch direction and a touch intensity of the charged body.