Touch sensing device and display device using the same

• US 9,223,425 B1
• Filed: 12/09/2014
• Issued: 12/29/2015
• Est. Priority Date: 09/10/2014
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, Jaeseung, Shin, Seungrok, Lee, Jeonghoon
• Primary Examiner(s): Faragalla, Michael
• Application Number:
  US14/564,318
• Time in Patent Office: 385 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A touch sensing device comprises a common electrode divided into a plurality of sensor electrodes, a plurality of sensor lines respectively connected to the plurality of sensor electrodes, a feedback voltage transmitter, and a common voltage compensator. The feedback voltage transmitter includes a feedback line, a plurality of switching elements configured to selectively connect the sensor lines to the feedback line, and a feedback control line configured to control selection of the switching elements. The common voltage compensator is configured to receive a feedback voltage supplied to the sensor lines through the feedback line while the sensor lines are connected to the feedback line through the plurality of switching elements, and compensate the feedback voltage to a reference voltage level.

Claims

1. A touch sensing device, comprising:

a common electrode divided into a plurality of sensor electrodes;

a plurality of sensor lines respectively connected to the plurality of sensor electrodes;

a feedback voltage transmitter including;

a feedback line;

a plurality of switching elements configured to selectively connect the sensor lines to the feedback line so that a common voltage of the sensor lines is applied to the feedback line; and

a feedback control line configured to control selection of the switching elements; and

a common voltage compensator configured to;

receive a feedback voltage through the feedback line while the sensor lines are connected to the feedback line through the plurality of switching elements; and

compensate the feedback voltage to a reference voltage level,

wherein the common voltage is a voltage commonly supplied to the common electrode through the sensor lines during a display driving period for displaying input image data;

wherein the sensor lines are equal in length; and

wherein the sensing device is configured to apply the common voltage to both ends of the sensor lines.

2. The touch sensing device of claim 1, wherein the common voltage compensator comprises an inverting amplifier,

the inverting amplifier comprising an inverting input terminal connected to the feedback line and a non-inverting input terminal to which a reference voltage is input, and an output terminal configured to output a feedback-compensated common voltage.

3. The touch sensing device of claim 1, wherein:

the common voltage compensator comprises a first inverting amplifier and a second inverting amplifier;

the first inverting amplifier comprises an inverting input terminal connected to the feedback line and a non-inverting input terminal to which a reference voltage is input, and is configured to supply a feedback-compensated common voltage to the sensor lines; and

the second inverting amplifier comprises an inverting input terminal connected to the sensor lines and a non-inverting input terminal to which the reference voltage is input, and is configured to supply the feedback-compensated common voltage to the feedback line.

4. The sensing device of claim 2, wherein the common voltage compensator comprises a multiplexer configured to vary the voltage level of the reference voltage in response to a selection signal.

5. The sensing device of claim 2, wherein the common voltage compensator further comprises:

a first multiplexer configured to vary the voltage level of the reference voltage in response to a first selection signal; and

a second multiplexer configured to select either the output voltage of the first multiplexer or the voltage of the touch driving signal in response to a second selection signal.

6. The sensing device of claim 3, wherein the common voltage compensator comprises a multiplexer configured to vary the voltage level of the reference voltage in response to a selection signal.

7. The sensing device of claim 3, wherein the common voltage compensator comprises:

a first multiplexer configured to vary the voltage level of the reference voltage in response to a first selection signal; and

a second multiplexer configured to select either the output voltage of the first multiplexer or the voltage of the touch driving signal in response to a second selection signal.

8. A display device, comprising:

a display panel including;

a common electrode divided into a plurality of sensor electrodes;

a feedback line;

a plurality of sensor lines respectively to the plurality of sensor electrodes;

a plurality of switching elements configured to selectively connect the sensor lines to the feedback line so that a common voltage of the sensor lines is applied to the feedback line;

a feedback control line configured to control selection of the switching elements; and

a common voltage compensator configured to;

receive a feedback voltage through the feedback line while the sensor lines are connected to the feedback line through the plurality of switching elements; and

compensate the feedback voltage to a reference voltage level,

wherein the common voltage is a voltage commonly supplied to the common electrode through the sensor lines during a display driving period for displaying input image data;

wherein the sensor lines are equal in length; and

wherein the display device is configured to apply the common voltage to both ends of the sensor lines.

9. The display device of claim 8, wherein the common voltage compensator comprises an inverting amplifier, the inverting amplifier comprising an inverting input terminal connected to the feedback line and a non-inverting input terminal to which a reference voltage is input, and an output terminal configured to output a feedback-compensated common voltage.

10. The display device of claim 8, wherein:

the common voltage compensator comprises a first inverting amplifier and a second inverting amplifier;

the first inverting amplifier comprises an inverting input terminal connected to the feedback line and a non-inverting input terminal to which a reference voltage is input, and is configured to supply a feedback-compensated common voltage to the sensor lines; and

the second inverting amplifier comprises an inverting input terminal connected to the sensor lines and a non-inverting input terminal to which the reference voltage is input, and is configured to supply the feedback-compensated common voltage to the feedback line.

11. The display device of claim 9, wherein the common voltage compensator comprises a multiplexer configured to vary the voltage level of the reference voltage in response to a selection signal.

12. The display device of claim 9, wherein the common voltage compensator comprises:

a first multiplexer configured to vary the voltage level of the reference voltage in response to a first selection signal; and

a second multiplexer configured to select either the output voltage of the first multiplexer or the voltage of the touch driving signal in response to a second selection signal.

13. The display device of claim 10, wherein the common voltage compensator comprises a multiplexer configured to vary the voltage level of the reference voltage in response to a selection signal.

14. The display device of claim 10, wherein the common voltage compensator comprises:

a first multiplexer configured to vary the voltage level of the reference voltage in response to a first selection signal; and

a second multiplexer configured to select either the output voltage of the first multiplexer or the voltage of the touch driving signal in response to a second selection signal.