Apparatus and method for driving touch sensor

• US 8,884,917 B2
• Filed: 12/27/2011
• Issued: 11/11/2014
• Est. Priority Date: 12/31/2010
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Seo, Seong-Mo
• Primary Examiner(s): CERULLO, LILIANA P
• Application Number:
  US13/337,366
• Publication Number:
  US 20120169660A1
• Time in Patent Office: 1,050 Days
• Field of Search: 345173-178, 178 1801- 1811
• US Class Current: 345/174
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Disclosed is an apparatus and method for driving a touch sensor in which a group sensing method per region or a local channel sensing method in a selected region is used depending upon whether touch is made, thereby reducing touch calculation time and power consumption. An apparatus for driving a touch sensor, including a plurality of first conduction lines and a plurality of second conduction lines, includes a touch controller to divide the touch sensor into a plurality of regions, to periodically sense whether touch has been made per region using a group sensing mode, to select a touch region when the touch region is detected, and to sense whether touch has been made per channel using a channel sensing mode only in the selected region.

Claims

1. An apparatus for driving a touch sensor comprising a plurality of first conduction lines and a plurality of second conduction lines, the apparatus comprising a touch controller to divide the touch sensor into a plurality of regions, to periodically sense whether touch has been made per region using a group sensing mode, to select a touch region when the touch region is detected, and to sense whether touch has been made per channel using a channel sensing mode only in the selected region,

wherein

the touch controller uses a group self-sensing mode in which the first conduction lines and second conduction lines are grouped per region to sense self-capacitance variation per region or a group mutual sensing mode to sense mutual-capacitance variation per region as the group sensing mode, and

the touch controller uses a channel mutual sensing mode to sense mutual-capacitance variation per channel in the selected region as the channel sensing mode in the selected region,

wherein the touch controller comprises:

a first self mode block to drive the first conduction lines in the group self-sensing mode;

a first mutual mode block to drive the first conduction lines in the group mutual sensing mode and in the channel mutual sensing mode in the selected region;

a first mode switching block to connect the first self mode block or the first mutual mode block to the first conduction lines according to the sensing mode;

a second self mode block to drive the second conduction lines in the group self-sensing mode;

a second mutual mode block to drive the second conduction lines in the group mutual sensing mode and in the channel mutual sensing mode in the selected region;

a second mode switching block to connect the second self mode block or the second mutual mode block to the second conduction lines according to the sensing mode; and

a microcontroller unit to control the first and second self mode blocks, the first and second mutual mode blocks and the first and second mode switching blocks,

wherein, when the group sensing mode, the first mode switching block selects one of the first self mode block and the first mutual mode block and the second mode switching block selects one of the second self mode block and the second mutual mode block according to whether the group sensing mode is one of the group self-sensing mode and group mutual sensing mode.

2. The apparatus according to claim 1, wherein the first self mode block comprises:

a first drive signal generator to generate and output signals to drive the first conduction lines;

a first grouping switch block to group the first conduction lines connected through the first mode switching block per region according to group self-sensing mode control of the microcontroller unit; and

a first self-sensing unit connected to an output line of the first drive signal generator via a feedback line to sense self-capacitance variation of the first conduction lines grouped per region.

3. The apparatus according to claim 2, wherein the second self mode block comprises:

a second drive signal generator to generate and output signals to drive the second conduction lines;

a second grouping switch block to group the second conduction lines connected through the second mode switching block per region according to group self-sensing mode control of the microcontroller unit; and

a second self-sensing unit connected to an output line of the second drive signal generator via a feedback line to sense self-capacitance variation of the second conduction lines grouped per region.

4. The apparatus according to claim 3, wherein the first mutual mode block comprises:

a third drive signal generator to generate and output signals to drive the first conduction lines;

a first channel switching block connected in common to the third drive signal generator and connected to the first conduction lines connected through the first mode switching block per channel to selectively switch the drive signals per channel according to the group mutual mode or channel mutual mode control of the microcontroller unit;

a third grouping switch block connected between the first channel switching block and the first mode switching block to group the first conduction lines connected through the first mode switching block per region according to the group mutual mode control of the microcontroller unit;

a first mutual sensing unit to sense mutual-capacitance variation of the first conduction lines grouped per region; and

a first transmitting and receiving switching block connected between the third drive signal generator and the first channel switching block and between the first mutual sensing unit and the first channel switching block to connect an end of the first channel switching block to an output end of the third drive signal generator or to an input end of the first mutual sensing unit according to transmitting and receiving mode control of the microcontroller unit.

5. The apparatus according to claim 4, wherein the second mutual mode block comprises:

a fourth drive signal generator to generate and output signals to drive the second conduction lines;

a second channel switching block connected in common to the fourth drive signal generator and connected to the second conduction lines connected through the second mode switching block per channel to switch the drive signals per channel according to the group mutual mode or channel mutual mode control of the microcontroller unit;

a fourth grouping switch block connected between the second channel switching block and the second mode switching block to group the second conduction lines connected through the second mode switching block per region according to the group mutual mode control of the microcontroller unit;

a second mutual sensing unit to sense mutual-capacitance variation of the second conduction lines grouped per region; and

a second transmitting and receiving switching block connected between the fourth drive signal generator and the second channel switching block and between the second mutual sensing unit and the second channel switching block to connect an end of the second channel switching block to an output end of the fourth drive signal generator or to an input end of the second mutual sensing unit according to transmitting and receiving mode control of the microcontroller unit.