TOUCH SENSING DEVICE AND METHOD FOR DRIVING THE SAME

• US 20130314342A1
• Filed: 12/12/2012
• Published: 11/28/2013
• Est. Priority Date: 05/25/2012
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: KIM, Sungchul, LEE, Junghan
• Granted Patent: US 9,292,117 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A touch sensing device includes a touch screen coupled with a display panel including data lines, gate lines crossing the data lines, and pixels arranged in a matrix form, and a touch sensing circuit which supplies a driving signal to lines of the touch screen and senses a touch input. The touch sensing circuit detects an optimum sensing time, in which changes in a voltage change of the gate lines are maintained within a previously determined allowable range, in a touch screen drive period in which data is not written to the pixels of the display panel. The touch sensing circuit supplies the driving signal to the lines of the touch screen only in the optimum sensing time of the touch screen drive period.

Claims

1. A touch sensing device comprising:

a touch screen coupled with a display panel including data lines, gate lines crossing the data lines, and pixels arranged in a matrix form; and

a touch sensing circuit configured to supply a driving signal to lines of the touch screen and sense a touch input,

wherein the touch sensing circuit detects an optimum sensing time, in which a voltage change of the gate lines are maintained within a previously determined allowable range, in a touch screen drive period in which data is not written to the pixels of the display panel, and

wherein the touch sensing circuit supplies the driving signal to the lines of the touch screen only in the optimum sensing time of the touch screen drive period.

2. The touch sensing device of claim 1, further comprising a controller configured to time-divide one frame period into a display panel drive period and the touch screen drive period and control a display panel driving circuit and the touch sensing circuit,

wherein the display panel driving circuit writes data to the pixels of the display panel during the display panel drive period.

3. The touch sensing device of claim 2, wherein the touch sensing circuit counts sync signals received from the controller and detects the optimum sensing time based on a count value, and

wherein the optimum sensing time ranges from a time, at which a first transition period has passed from a start time point of the touch screen drive period, to a time which is advanced from an end time point of the touch screen drive period by a second transition period.

4. The touch sensing device of claim 3, wherein a ripple of a voltage measured in the gate lines during the optimum sensing time is less than a ripple of a voltage measured in the gate lines during the first and second transition periods.

5. The touch sensing device of claim 2, wherein the touch sensing circuit detects the voltage of the gate lines and detects the optimum sensing time based on changes in the detected voltage, and

wherein the optimum sensing time ranges from a time, at which a first transition period has passed from a start time point of the touch screen drive period, to a time which is advanced from an end time point of the touch screen drive period by a second transition period.

6. The touch sensing device of claim 5, wherein a ripple of a voltage measured in the gate lines during the optimum sensing time is less than a ripple of a voltage measured in the gate lines during the first and second transition periods.

7. A method for driving a touch sensing device including a touch screen coupled with a display panel including data lines, gate lines crossing the data lines, and pixels arranged in a matrix form, the method comprising:

setting a touch screen drive period, in which data is not written to the pixels of the display panel;

detecting an optimum sensing time, in which changes in a voltage of the gate lines are maintained within a previously determined allowable range, in the touch screen drive period; and

supplying a driving signal to lines of the touch screen only in the optimum sensing time of the touch screen drive period.

8. The method of claim 7, wherein the optimum sensing time ranges from a time, at which a first transition period has passed from a start time point of the touch screen drive period, to a time which is advanced from an end time point of the touch screen drive period by a second transition period.

9. The method of claim 8, wherein a ripple of a voltage measured in the gate lines during the optimum sensing time is less than a ripple of a voltage measured in the gate lines during the first and second transition periods.