Touch sensing system adjusting voltage of driving signal based on a distance from a touch sensing circuit and method for driving the same

Patent metadata

Field	Value
Publication number	US-9766755-B2
Application number	US-201314079798-A
Country	US
Kind code	B2
Filing date	Nov 14, 2013
Priority date	Nov 16, 2012
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A touch sensing system and a method for driving the same are disclosed. The touch sensing system includes a touch screen including touch sensors and a touch sensing circuit applying a driving signal to the touch sensors. The touch sensing circuit applies at least one first driving signal to a first position of the touch screen and applies at least one second driving signal to a second position of the touch screen. When RC delay of the first position is less than RC delay of the second position, at least one of a width and a voltage of the second driving signal is greater than the first driving signal, or the number of second driving signals is more than the number of first driving signals.

First claim

What is claimed is:

1. A touch sensing system, comprising:
a touch screen including touch sensors; and
a touch sensing circuit comprising:
a touch transmission circuit configured to apply respective driving signals to the touch sensors; and
a touch reception circuit configured receive sensed voltages from the touch sensors,

wherein the touch transmission circuit is further configured to:
apply at least one first driving signal to a first touch sensor, and
apply at least one second driving signal to a second touch sensor,

wherein the first touch sensor is driven by the at least one first driving signal from the touch transmission circuit,
wherein the second touch sensor is driven by the at least one second driving signal from the touch transmission circuit,
wherein the touch sensing circuit is disposed on one side of the touch screen,
wherein a distance between the second touch sensor and the touch sensing circuit is longer than a distance between the first touch sensor and the touch sensing circuit,
wherein a voltage of the at least one second driving signal from the touch transmission circuit during a reception period is greater than a voltage of the at least one first driving signal from the touch transmission circuit during the reception period, and
wherein the voltage of each of the first and second driving signals increases in proportion to RC delay.

2. The touch sensing system of claim 1 , wherein:
the touch screen is divided into a plurality of blocks;
each of the plurality of blocks includes at least two lines to which the driving signal is applied;
the voltages of the driving signals applied to one block are the same; and
the voltage of the driving signal applied to a block having relatively large RC delay among the plurality of blocks is greater than the driving signal applied to a block having relatively small RC delay.

3. The touch sensing system of claim 1 , wherein:
the driving signal includes a pre-charging period during which a first voltage is applied to the touch sensors, and a high potential holding period during which a second voltage less than the first voltage is applied to the touch sensors; and
the pre-charging period is set to be earlier than the high potential holding period.

4. The touch sensing system of claim 3 , wherein:
the driving signal further includes a discharge acceleration period during which a third voltage less than the second voltage is applied to the touch sensors, and a reference potential period during which a reference voltage, which is less than the second voltage and greater than the third voltage, is applied to the touch sensors; and
the discharge acceleration period is set to be arranged between the high potential holding period and the reference potential period.

5. The touch sensing system of claim 4 , wherein the driving signal is generated in one waveform of a sine wave, a triangle wave, and a sawtooth wave.

6. The touch sensing system of claim 5 , wherein:
the touch screen is divided into a plurality of blocks;
each of the plurality of blocks includes at least two lines to which the driving signal is applied;
the first and third voltages applied to one block are equal to each other; and
the first and third voltages applied to one block of the plurality of blocks are set to be different from the first and third voltages applied to other blocks.

7. The touch sensing system of claim 6 , wherein the first and third voltages are proportional to the RC delay of the touch screen.

8. The touch sensing system of claim 7 , wherein the first and third voltages of the driving signal applied to a first block positioned closest to the touch sensing circuit are set to be less than the first and third voltages applied to other blocks or are set to a minimum value.

9. The touch sensing system of claim 8 , wherein:
the first and third voltages of the driving signal applied to a third block positioned farthest away from the touch sensing circuit are greater than the first and third voltages applied to other blocks; and
the first and third voltages of the driving signal applied to a second block positioned between the first block and the third block are greater than the first and third voltages of the driving signal applied to the first block and are less than the first and third voltages of the driving signal applied to the third block.

10. A method for driving a touch sensing system including a touch screen including touch sensors and a touch sensing circuit comprising a touch transmission circuit applying respective driving signal signals to the touch sensors and a touch reception circuit receiving sensed voltages from the touch sensors, the method comprising:
applying, by the touch transmission circuit, at least one first driving signal to a first touch sensor; and
applying, by the touch transmission circuit, at least one second driving signal to a second touch sensor,
wherein the first touch sensor is driven by the at least one first driving signal from the touch transmission circuit,
wherein the second touch sensor is driven by the at least one second driving signal from the touch transmission circuit,
wherein the touch sensing circuit is disposed on one side of the touch screen,
wherein a distance between the second touch sensor and the touch sensing circuit is longer than a distance between the first touch sensor and the touch sensing circuit,
wherein a voltage of the at least one second driving signal from the touch transmission circuit is greater than a voltage of the at least one first driving signal from the touch transmission circuit, and
wherein and the voltage of each of the first and second driving signals increases in proportion to RC delay.

11. The method of claim 10 , wherein:
the touch screen is divided into a plurality of blocks;
each of the plurality of blocks includes at least two lines to which the driving signal is applied;
the voltages of the driving signals applied to one block are the same; and
the voltage of the driving signal applied to a block having relatively large RC delay among the plurality of blocks is greater than the driving signal applied to a block having relatively small RC delay.

12. The method of claim 11 , wherein:
the driving signal includes a pre-charging period during which a first voltage is applied to the touch sensors, and a high potential holding period during which a second voltage less than the first voltage is applied to the touch sensors; and
the pre-charging period is set to be earlier than the high potential holding period.

13. The method of claim 12 , wherein:
the driving signal further includes a discharge acceleration period during which a third voltage less than the second voltage is applied to the touch sensors, and a reference potential period during which a reference voltage, which is less than the second voltage and greater than the third voltage, is applied to the touch sensors; and
the discharge acceleration period is set to be arranged between the high potential holding period and the reference potential period.

14. The method of claim 13 , wherein:
the touch screen is divided into a plurality of blocks;
each of the plurality of blocks includes at least two lines to which the driving signal is applied;
the first and third voltages applied to one block are equal to each other; and
the first and third voltages applied to one block of the plurality of blocks are set to be different from the first and third voltages applied to other blocks.

15. The method of claim 14 , wherein the first and third voltages are proportional to the RC delay of the

Assignees

• Lg Display Co Ltd

Inventors

• Seo Sangwoo
• Lee Jaedo
• Jeong Beom
• Choi Sungpil

Classifications

• G06F3/0416

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title

• G06F3/0443

  using a single layer of sensing electrodes · CPC title

• G06F3/04164

  Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads · CPC title