Touch sensing system and control method thereof

1 . A touch sensing system, comprising:

a capacitive touch panel;

a controller, coupled to with the capacitive touch panel and configured to scan the capacitive touch panel; and

a signal source, configured to provide a periodical signal for coupling to a user, such that the periodical signal can be coupled to the capacitive touch panel via the user;

wherein, when the signal source is activated to provide the periodical signal, the controller does not apply driving signals to the capacitive touch panel but only senses all electrodes of the capacitive touch panel.

2 . The touch sensing system according to claim 1 further comprising a conductor coupled to the signal source and configured to contact with the user.

3 . The touch sensing system according to claim 1 further comprising an antenna coupled to the signal source and configured to couple the periodical signal to the user.

4 . The touch sensing system according to claim 1 , wherein the capacitive touch panel includes a first electrode and a second electrode, wherein the first electrode is located in a first edge region of the capacitive touch panel, wherein the second electrode is located in a second edge region of the capacitive touch panel, wherein the first edge region adjacent to the second edge region, wherein the first electrode is perpendicular to the second electrode, wherein the signal source is connected to the first electrode during a first time interval, and wherein the signal source is connected to the second electrode during a second time interval which is after the first time interval.

5 . The touch sensing system according to claim 1 , wherein the signal source includes:

an oscillator, configured to generate an oscillation signal; and

a booster circuit, coupled to the oscillator and used to boost the oscillation signal to generate the periodical signal.

6 . The touch sensing system according to claim 1 , wherein the controller is coupled to the signal source, and wherein the controller activates the signal source when liquid is present on a surface of the capacitive touch panel.

7 . The touch sensing system according to claim 6 , wherein the periodical signal provided by the signal source has a frequency ranging from 1.2 MHz to 2 MHz when the liquid is water.

8 . The touch sensing system according to claim 6 , wherein the periodical signal provided by the signal source has a frequency ranging from 10 MHz to 100 MHz when the liquid is saline.

9 . The touch sensing system according to claim 6 , wherein the controller performs a first mutual-capacitance scan on the capacitive touch panel with a driving signal having a first frequency to generate a first mutual-capacitance sensing information, wherein the controller performs a second mutual-capacitance scan on the capacitive touch panel with a driving signal having a second frequency to generate a second mutual-capacitance sensing information, wherein the first frequency is different from the second frequency, and wherein the controller determines whether the liquid is water or saline according to the first mutual-capacitance sensing information and the second mutual-capacitance sensing information.

10 . A touch sensing system comprising:

a capacitive touch panel;

a controller, coupled to the capacitive touch panel and configured to scan the capacitive touch panel, wherein the controller has a high-voltage terminal and a low-voltage terminal, and wherein a combination of the high-voltage terminal and the low-voltage terminal is configured to provide power to the controller; and

a signal source, configured to provide a periodical signal to the high-voltage terminal or to both the high-voltage terminal and the low-voltage terminal.

11 . The touch sensing system according to claim 10 , wherein the signal source includes:

an oscillator, configured to generate an oscillation signal; and

a booster circuit, coupled to the oscillator and configured to boost the oscillation signal to generate the periodical signal.

12 . The touch sensing system according to claim 10 further comprising a first filter coupled between the high-voltage terminal and the signal source and configured to prevent the periodical signal from feeding back from the high-voltage terminal to the signal source.

13 . The touch sensing system according to claim 10 , wherein the signal source is controlled by the controller, and the controller activates the signal source when liquid is present on a surface of the capacitive touch panel.

14 . The touch sensing system according to claim 13 , wherein the periodical signal provided by the signal source has a frequency ranging from 1.2 MHz to 2 MHz when the liquid is water.

15 . The touch sensing system according to claim 13 , wherein the periodical signal provided by the signal source has a frequency ranging from 10 MHz to 100 MHz when the liquid is saline.

16 . The touch sensing system according to claim 13 , wherein the controller performs a first mutual-capacitance scan on the capacitive touch panel with a driving signal having a first frequency to generate a first mutual-capacitance sensing information, wherein the controller performs a second mutual-capacitance scan on the capacitive touch panel with a driving signal having a second frequency to generate a second mutual-capacitance sensing information, wherein the first frequency is different from the second frequency, and wherein the controller determines whether the liquid is water or saline according to the first mutual-capacitance sensing information and the second mutual-capacitance sensing information.

17 . A control method of a touch sensing system, wherein the touch sensing system includes a capacitive touch panel and a controller, the controller is coupled to the capacitive touch panel and has a high-voltage terminal and a low-voltage terminal, a combination of the high-voltage terminal and the low-voltage terminal is configured to provide power to the controller, the control method comprising:

A. providing a periodical signal to the high-voltage terminal of the controller or to both the high-voltage terminal and the low-voltage terminal of the controller; and

B. scanning the capacitive touch panel by the controller.

18 . The control method according to claim 17 , wherein the step A is performed only when liquid is present on a surface of the capacitive touch panel.

19 . The control method according to claim 18 , wherein the periodical signal has a frequency ranging from 1.2 MHz to 2 MHz when the liquid is water.

20 . The control method according to claim 18 , wherein the periodical signal has a frequency ranging from 10 MHz to 100 MHz when the liquid is saline.

21 . The control method according to claim 20 , wherein a step of determining that the liquid is saline comprises:

using a driving signal having a first frequency to perform a first mutual-capacitance scan on the capacitive touch panel to generate first mutual-capacitance sensing information;

using a driving signal having a second frequency to perform a second mutual-capacitance scan on the capacitive touch panel to generate second mutual-capacitance sensing information; and

determining that the liquid is saline according to the first mutual-capacitance sensing information and the second mutual-capacitance sensing information.

22 . A control method of a touch sensing system, the touch sensing system includes a capacitive touch panel and a controller, the control method comprising:

A. coupling a periodical signal to a user such that the periodical signal can be coupled to the capacitive touch panel via the user; and

B. scanning the capacitive touch panel;

wherein, the scanning performed in the step B does not apply driving signals to the capacitive touch panel but only senses all electrodes of the capacitive touch panel.

23 . The control method according to claim 22 , wherein the step A is executed only when liquid is present on a surface of the capacitive touch panel.

24 . The control method according to claim 23 , wherein the periodical signal has a frequency ranging from 1.2 MHz to 2 MHz when the liquid is water.

25 . The control method according to claim 23 , wherein the periodical signal has a frequency ranging from 10 MHz to 100 MHz when the liquid is saline.

26 . The control method according to claim 25 , wherein a step of determining that the liquid is saline comprises:

using a driving signal having a first frequency to perform a first mutual-capacitance scan on the capacitive touch panel to generate first mutual-capacitance sensing information;

using a driving signal having a second frequency to perform a second mutual-capacitance scan on the capacitive touch panel to generate second mutual-capacitance sensing information; and

determining that the liquid is saline according to the first mutual-capacitance sensing information and the second mutual-capacitance sensing information.