Touch sensor and touch sensing method
View Patent ↗A touch sensor includes a panel including display pixels and sensing nodes, a touch-sensing block configured to sense a change in capacitance of the sensing nodes, and a timing controller configured to generate state information based on a polarity of data and/or an inflow of electrostatic discharge to the panel and/or a peripheral temperature and/or an on or off state of the panel. The touch-sensing block senses a presence or absence of a touch on or over the sensing nodes based on the state information and the change in capacitance of the sensing nodes.
1. A touch sensor comprising:
a panel including display pixels and sensing nodes;
a sensing unit configured to output a changed value of raw data in response to a change in capacitance of the sensing nodes;
a timing controller configured to generate state information based on a polarity of data to the panel; and
a data processor configured to determine a presence or absence of a touch on or over the sensing nodes based on the changed value of the raw data relative to a reference data value,
wherein the data processor sets (i) a first reference value for the reference data value when the display pixels are driven by positive polarity data and (ii) a second reference value different from the first reference value for the reference data value when the display pixels are driven by negative polarity data.
2. The touch sensor according to claim 1 , further comprising a data drive unit configured to provide the data to the panel, wherein the polarity of the data alternates in successive data frames.
3. The touch sensor according to claim 2 , wherein the polarity of the data alternates between a positive polarity and a negative polarity in successive data frames.
4. The touch sensor according to claim 1 , wherein the data processor controls the reference data value based on the state information and determines presence or absence of touch on or over the sensing nodes based on one of the first and second reference values and the change in the raw data.
5. The touch sensor according to claim 1 , wherein the data processor corrects the change in the raw data based on the state information and determines the presence or absence of the touch on or over the sensing nodes based on the corrected change in the raw data and the reference data value.
6. The touch sensor according to claim 5 , wherein:
the display pixels comprise a plurality of groups,
each of the plurality of groups includes two or more display pixels sharing one common electrode, and
the sensing nodes comprise the common electrodes.
7. The touch sensor according to claim 6 , wherein the data processor corrects the change in the raw data from the sensing nodes based on a difference between a number of positive polarity data and a number of negative polarity data.
8. The touch sensor according to claim 1 , wherein the polarity of the data to the panel is a vertical polarity, and the state information comprises a vertical polarity control signal.