TWI692711B - Method of detecting liquid on capacitive touch panel and controller thereof - Google Patents

Abstract

The present invention relates to a method of detecting liquid on capacitive touch panel and controller thereof. In the detecting method, a sensed value of each of multiple first sensing electrodes of the capacitive touch panel is obtained and used as a first sensing information. Another sensed value of each of multiple sensing points of the capacitive touch panel is further obtained. The sensed value of the sensing points on each first sensing electrode are added to generate a second sensing information. According to the first and second sensing information, a difference information is determined. A liquid on the capacitive touch panel is determined according to the difference information.

Description

Liquid detection method and controller on capacitive touch panel

The invention relates to an object detection method on a capacitive touch panel, in particular to a liquid detection method on a capacitive touch panel.

The capacitive touchpad determines the touch information of an object according to the change in capacitance, such as the type of object. When there is liquid (such as water) on the capacitive touch panel and the user's finger is in contact with the liquid, the conventional capacitive touch panel controller cannot recognize that liquid is present on the capacitive touch panel.

The main object of the present invention is to provide a liquid detection method and controller for a capacitive touch panel.

According to an embodiment of the invention, a liquid detection method on a capacitive touch panel includes the following steps (a) to (d); wherein, the capacitive touch panel includes multiple first sensing electrodes and multiple A second sensing electrode, the intersection of the plurality of first sensing electrodes and the plurality of second sensing electrodes constitutes a plurality of sensing points; (a) performing self-capacitance measurement on the plurality of first sensing electrodes to obtain the first sensing Information, the first sensing information includes the sensing amount of each of the first sensing electrodes; (b) Perform mutual capacitance measurement on the multiple sensing points to obtain the inductance of each of the sensing points; (c) Calculate the sum of the inductances of the multiple sensing points on each first sensing electrode to obtain A second sensing information; and (d) according to the first sensing information and the second sensing information, determine whether liquid exists on the capacitive touch panel.

According to an embodiment of the present invention, a controller of a capacitive touchpad is used to detect whether liquid exists on a touchpad. The touchpad includes a plurality of first sensing electrodes and a plurality of second sensing electrodes. The intersection of the first sensing electrode and the plurality of second sensing electrodes constitutes a plurality of sensing points; the controller includes: a storage medium and a processor; wherein the storage medium is used to store firmware programs, and the processor It is coupled to the storage medium, and the processor executes the preemptive steps (a) to (d) by executing the firmware program.

According to an embodiment of the invention, the capacitive touch panel includes a plurality of first sensing electrodes in the X direction and a plurality of second sensing electrodes in the Y direction, the plurality of first sensing electrodes and the plurality of second sensing The intersection of the electrodes constitutes a plurality of sensing points; (a) performing self-capacitance measurement on the plurality of first and second sensing electrodes to obtain first X-axis sensing information and first Y-axis sensing information, the first X The axis sensing information includes the sensing amount of each of the first sensing electrodes, and the first Y-axis sensing information includes the sensing amount of each of the second sensing electrodes; (b) performing mutual capacitance measurement on the plurality of sensing points to obtain The amount of induction of each of the sensing points; (c) separately calculating the sum of the amounts of induction of the plurality of sensing points on each of the first sensing electrodes to obtain a second X-axis sensing information, and calculating each of the first The sum of the sensing amounts of the plurality of sensing points on the two sensing electrodes to obtain second Y-axis sensing information; and (d) according to the first X-axis sensing information and the first Y-axis sensing information and the second X-axis sensing Information and the second Y-axis sensing information to determine whether liquid exists on the capacitive touch panel.

With the method provided by the present invention and the controller implementing the method, the liquid on the capacitive touch panel can be identified.

1: Capacitive touch device

10: Capacitive touchpad

100: Sensing point

20: Controller

21: Drive unit

22: Sensing unit

221: Sensing circuit

222: Sample and hold circuit

23: processor

231: Storage media

30: liquid

FIG. 1 is a schematic structural diagram of a capacitive touch device of the present invention.

2A is a flowchart of a liquid detection method of a capacitive touch panel according to the present invention.

FIG. 2B illustrates an embodiment of step S40 of FIG. 2A.

FIG. 3 provides first X-axis sensing information and first Y-axis sensing information of the capacitive touch panel.

FIG. 4A provides the sensing quantities of multiple sensing points of the capacitive touch panel.

4B is a schematic diagram of the second X-axis sensing information and the second Y-axis sensing information of the capacitive touch panel.

4C is a schematic diagram of the third X-axis sensing information and the third Y-axis sensing information of the capacitive touch panel.

FIG. 4D is a schematic diagram of X-axis difference information and Y-axis difference information of the capacitive touch panel.

FIG. 5 illustrates the composition of the controller in FIG.

FIG. 6 provides an embodiment of the sensing unit in FIG. 5

7A to 7D are signal waveform diagrams illustrating the driving signals and the sensing time used by the controller according to the present invention when performing self-capacitance measurement and mutual capacitance measurement.

First, please refer to FIG. 1, a capacitive touch device 1 includes a capacitive touch panel 10 and a controller 20. The capacitive touch panel 10 may be transparent or opaque. The capacitive touch panel 10 includes a plurality of sensing electrodes X1~Xn in the X direction, and includes a plurality of sensing electrodes in the Y direction The sensing electrodes Y1~Ym, and the intersection of the sensing electrodes X1~Xn and the sensing electrodes Y1~Ym constitute a plurality of sensing points 100. The positions of the sensing electrodes X1 to Xn and the sensing electrodes Y1 to Ym in FIG. 1 are only schematic, and are not intended to limit the present invention. The controller 20 is coupled to the capacitive touch panel 10 for detecting the sensing amounts of the plurality of sensing electrodes X1~Xn, the plurality of sensing electrodes Y1~Ym, and the plurality of sensing points 100. The reference number 30 represents a liquid (for example, water) and appears on the capacitive touch panel 10. A conductor (eg, finger F) contacts the liquid 30, so that the liquid 30 is grounded.

For convenience of description, in the examples provided in FIG. 3, FIG. 4A to FIG. 4D, the capacitive touch panel 10 includes 7 first sensing electrodes X1~X7 in the X direction and 12 second sensing electrodes Y1~ in the Y direction Y12. The intersection of the first sensing electrodes X1~X7 and the second sensing electrodes Y1~Y12 constitute 84 sensing points 100.

Please refer to FIG. 2A for a flow chart of the liquid detection method of the capacitive touch panel 10 according to the present invention. The liquid detection method includes the following steps S10 to S40.

In step S10, the controller 20 performs self-capacitance measurement on the first sensing electrodes X1~X7 in the X direction and the second sensing electrodes Y1~Y12 in the Y direction, as shown in FIG. 3 The first X-axis sensing information dV_Self_X and the first Y-axis sensing information dV_Self_Y are shown. The first X-axis sensing information dV_Self_X includes the sensing amount of each of the first sensing electrodes X1~X7. As shown in FIG. 3, the inductance of the first sensing electrode X1 is 8, and the inductance of the first sensing electrode X7 is 22. The first Y-axis sensing information dV_Self_Y includes the sensing amount of each second sensing electrode Y1~Y12. As shown in FIG. 3, the induction of the second induction electrode Y1 is 0, and the induction of the second induction electrode Y12 is 4.

The aforementioned self-capacitance measurement includes driving multiple sensing electrodes simultaneously. In one embodiment, when one of the first sensing electrode or the second sensing electrode is driven and read, the adjacent first or second sensing electrode of the driven first or second sensing electrode also has Drive signals of the same phase. For example, when measuring the sensing amount of the first sensing electrode X3, the controller 20 simultaneously outputs a driving signal The first sensing electrode X3 and two first sensing electrodes X2 and X4 adjacent to the first sensing electrode X3. When measuring the sensing amount of the second sensing electrode Y3, the controller 20 simultaneously transmits the driving signal to the second sensing electrode Y3 and the two second sensing electrodes Y2 and Y4 adjacent to the second sensing electrode Y3. In another embodiment, the self-capacitance measuring system outputs the driving signals of the same phase to all the first sensing electrodes X1~X7 at the same time, and then receives the signals of the first sensing electrodes X1~X7 together. The second sensing electrodes Y1~Y12 output driving signals of the same phase, and then receive the signals of the second sensing electrodes Y1~Y12 together.

In step S20, the controller 20 performs mutual-capacitance measurement on the plurality of sensing points 100, and obtaining the sensing amounts of the plurality of sensing points 100 is shown in FIG. 4A. In FIG. 4A, the induction amount of the induction point 100 formed by the first induction electrode X1 and the second induction electrode Y1 is 3, and the induction amount of the induction point 100 formed by the first induction electrode X3 and the second induction electrode Y7 is 178. The details of mutual capacitance measurement are well known to those skilled in the field of touch technology, and will not be described in detail here.

The order of step S10 and step S20 can be exchanged. In one embodiment, step S20 is performed first, and then step S10 is performed.

After obtaining the sensing amount of the plurality of sensing points 100, step S30 is performed to respectively calculate the sum of the sensing amounts of the plurality of sensing points 100 on each of the first sensing electrodes X1~X7 to obtain the second X-axis sensing information dVsum_Mutual_X, and respectively The sum of the sensing amounts of the plurality of sensing points 100 on each of the second sensing electrodes Y1~Y12 is calculated to obtain the second Y-axis sensing information dVsum_Mutual_Y. FIG. 4B shows the second X-axis sensing information dVsum_Mutual_X and the second Y-axis sensing information dVsum_Mutual_Y. Each of the first sensing electrodes X1~X7 and each of the second sensing electrodes Y1~Y12 respectively correspond to an accumulated sensing quantity. For example, in FIG. 4B, the first sensing electrode X1 includes 12 sensing points 100, and the sum of the sensing amounts of the 12 sensing points 100 is 103. The second sensing electrode Y1 includes 7 sensing points 100, and the sum of the sensing amounts of the 7 sensing points 100 is 24.

Step S40 is based on the first X-axis sensing information dV_Self_X, the second X-axis sensing information dVsum_Mutual_X, the first Y-axis sensing information dV_Self_Y, and the second Y-axis sensing information dVsum_Mutual_Y to determine whether liquid exists in the capacitive touch On board 10.

An embodiment of step S40 includes determining an X-axis difference information dV_diff_X based on the first X-axis sensing information dV_Self_X and the second X-axis sensing information dVsum_Mutual_X, and sensing based on the first Y-axis sensing information dV_Self_Y and the second Y-axis sensing information The information dVsum_Mutual_Y determines a Y-axis difference information dV_diff_Y, and determines whether liquid exists on the capacitive touch panel 10 according to the X-axis difference information dV_diff_X and/or the Y-axis difference information dV_diff_Y. More detailed steps are shown in Figure 2B.

Step S401 is to normalize the second X-axis sensing information dVsum_Mutual_X according to the first X-axis sensing information dV_Self_X to obtain a third X-axis sensing information Normalized_dVsum_Mutual_X. In an embodiment, the second X-axis sensing information is normalized_dVsum_Mutual_X. The sensing amount "46" of the first sensing electrode X3 of the maximum value "466" in the sensing information dVsum_Mutual_X is normalized to the second X-axis sensing information dVsum_Mutual_X to obtain the third X-axis sensing information Normalized_dVsum_Mutual_X as shown in FIG. 4C . The normalization operation is to multiply all values of the second X-axis sensing information dVsum_Mutual_X by a ratio of 46/466, where the denominator "466" is the maximum value in the second X-axis sensing information dVsum_Mutual_X, corresponding to the first sensing electrode X3, the numerator "46" is the inductance of the first sensing electrode X3.

Step S402 is to normalize the second Y-axis sensing information dVsum_Mutual_Y according to the first Y-axis sensing information dV_Self_Y to obtain a third Y-axis sensing information Normalized_dVsum_Mutual_Y. In one embodiment, the second Y-axis sensing information dVsum_Mutual_Y is normalized based on the sensing amount "209" of the second sensing electrode Y8 corresponding to the maximum value "564" in the second Y-axis sensing information dVsum_Mutual_Y. The third Y-axis sensing information Normalized_dVsum_Mutual_Y shown in FIG. 4C is obtained. The normalization operation is to convert the second Y-axis induction data All values of dVsum_Mutual_Y are multiplied by a ratio 209/564, where the denominator "564" is the maximum value in the second Y-axis sensing information dVsum_Mutual_Y, corresponding to the second sensing electrode Y8, and the numerator "209" is the value of the second sensing electrode Y8 Induction.

Step S403 is to subtract the third X-axis sensing information Normalized_dVsum_Mutual_X from the first X-axis sensing information dV_Self_X to obtain X-axis difference information including multiple X-axis difference values. The multiple X-axis difference values are shown in the X-axis difference information dV_diff_X in FIG. 4D. For example, in the first X-axis sensing information dV_Self_X, the sensing amount of the first sensing electrode X3 is 46, and in the third X-axis sensing information Normalized_dVsum_Mutual_X, the corresponding value of the first sensing electrode X3 is 46. Subtract 46 from 46, which is the X-axis difference value 0 corresponding to the first sensing electrode X3 in FIG. 4D.

Step S404 is to subtract the third Y-axis sensing information Normalized_dVsum_Mutual_Y from the first Y-axis sensing information dV_Self_Y to obtain a Y-axis difference information including multiple Y-axis difference values. The multiple Y-axis differences are shown in the difference information dV_diff_Y of FIG. 4D. For example, in the first Y-axis sensing information dV_Self_Y, the sensing amount of the second sensing electrode Y9 is 146, and in the third Y-axis sensing information Normalized_dVsum_Mutual_Y, the corresponding value of the second sensing electrode Y9 is 72. Subtracting 72 from 146 is the Y-axis difference 74 corresponding to the second sensing electrode Y9 in FIG. 4C.

In step S405, a plurality of differences between the X-axis difference information dV_diff_X and the Y-axis difference information dV_diff_Y are compared with a threshold value to determine the number of differences greater than the threshold value. For example, assuming that the critical value is 50, comparing multiple X-axis difference values in the X-axis difference information dV_diff_X with the critical value 50, the number of X-axis difference values greater than the critical value is 2 and the Y-axis By comparing multiple Y-axis differences in the difference information dV_diff_Y with the critical value 50, the number of Y-axis differences greater than the critical value can be obtained as 2.

Step S406 is to determine whether liquid exists on the capacitive touch panel 10 according to the number of differences greater than the threshold obtained in step S405. An embodiment of step S406 is that when the number of differences greater than the critical value is greater than 0 (whether in the X or Y direction), it is determined that there is liquid On the capacitive touch panel 10. According to the comparison result of the foregoing step S405, there are four differences greater than the critical value, so step S406 determines that liquid is present on the capacitive touch panel 10.

The order of the various steps of the above-described embodiment can be changed. It can be understood from the foregoing embodiment that the controller 20 can determine whether liquid exists on the touch panel 10 according to the difference information in a single direction (X or Y). Therefore, it is feasible to omit some steps of FIGS. 2A and 2B. For example, the steps of obtaining the first Y-axis sensing information, the second Y-axis sensing information, and the Y-axis difference information can be omitted, and the controller 20 according to the number of differences in the X-axis difference information greater than the critical value 50 is 2 , It can be judged that liquid exists on the touch panel 10.

From the above description, it can be understood that the present invention provides a liquid detection method for a capacitive touch panel. The capacitive touch panel includes a plurality of first sensing electrodes and a plurality of second sensing electrodes. The intersection of the sensing electrode and the plurality of second sensing electrodes constitutes a plurality of sensing points; the liquid detection method includes the following steps: (a) performing self-capacitance measurement on the plurality of first sensing electrodes to obtain first sensing information, the The first sensing information includes the sensing amount of each first sensing electrode; (b) performing mutual capacitance measurement on the plurality of sensing points to obtain the sensing amount of each sensing point; (c) calculating each first sensing separately The sum of the sensing amounts of the plurality of sensing points on the electrode to obtain a second sensing information; and (d) according to the first sensing information and the second sensing information, determine whether there is liquid in the capacitive touch panel on.

FIG. 5 shows an embodiment of the controller 20. The controller 20 includes a driving unit 21, a sensing unit 22, a processor 23 and a storage medium 231. The processor 23 is coupled to the storage medium 231, the driving unit 21 and the sensing unit 22. The processor 23 executes the firmware program stored in the storage medium 231 to control the operation of the driving unit 21 and the sensing unit 22 and generate touch information, such as the position and number of objects, according to the output of the sensing unit 22. In an embodiment, the controller 20 is used for The self-capacitance measurement is performed on the response electrodes X1~Xn and the second sensing electrodes Y1-Ym, and the mutual-capacitance measurement is performed on the multiple sensing points 100. In one embodiment of the self-capacitance measurement, the driving unit 21 provides a driving signal to the first sensing electrodes X1~Xn and the second sensing electrodes Y1~Ym, and the sensing unit 22 senses the first sensing electrodes X1~Xn And the second sensing electrodes Y1~Ym to obtain the inductance of each of the first and second sensing electrodes. An embodiment of the mutual capacitance measurement is that the driving unit 21 provides a driving signal to the first sensing electrodes X1~Xn in the X direction, and the second sensing electrodes Y1~Ym in the Y direction are sensed by the sensing unit 22 to The inductance of multiple inductance points 100 is obtained. The processor 21 implements the aforementioned liquid detection method by executing the firmware program stored in the storage medium 231.

In one embodiment, the sensing unit 22 includes at least one sensing circuit 221 and at least one sample and hold circuit 222. One embodiment of the sensing circuit 221 and the sample-and-hold circuit 222 is shown in FIG. 6. The sensing circuit 221 includes a sensing capacitor C ₁ , a switch SW ₁ and an operational amplifier OP. Sensing capacitor C ₁ is connected between a first input terminal of the operational amplifier OP IN ₁ and the output terminal OUT, out switch SW ₁ in parallel with the sensing capacitance C _1. The output terminal OUT of the operational amplifier OP is connected to the sample-and-hold circuit 222. The sample-and-hold circuit 222 includes a switch SW ₂ and a sampling capacitor C _{2. The} switch SW _{2 is} connected between the output terminal OUT of the operational amplifier OP and the sampling capacitor C ₂ . One end of the capacitor C ₂ is grounded, and the other end is connected to the output terminal O/P of the sample-and-hold circuit 222.

The operation of the sensing circuit 221 is described below. In the first stage, the switch SW _{1 is} turned on, so that the charge amount of the sensing capacitor C ₁ is zero. Out switch SW ₁ turned off in a second phase, the switch SW ₂ is turned on, and a first input terminal of the operational amplifier OP is connected to IN ₁ object to be measured (i.e. sensing point 100, the first sensing electrode or the second sensing electrode) for sensing . When the switch SW ₂ is turned on, the output voltage of the operational amplifier OP ₂ on the sampling capacitor C charged, the voltage value of the sampling capacitor C ₂ is equal to the output voltage of the operational amplifier OP.

The voltage of the sampling capacitor C ₂ is related to the length RT of the switch SW _{2 being} turned on. In one embodiment, the length of time RT is determined according to the time when the output voltage of the operational amplifier OP reaches a stable time. In different embodiments, the length RT can also be controlled so that the switch SW ₂ is turned off before the output voltage of the operational amplifier OP reaches a stable level. After the switch SW _{2 is} turned off, the voltage of the sampling capacitor C ₂ is used to determine an inductance.

The voltage of the sampling capacitor C ₂ is converted into a digital value by an analog-to-digital converter (not shown in the figure). In one embodiment, the digital value minus a reference value is used as the inductance. The output value of the analog-to-digital converter when the object touches. The reference values of the sensing points 100 or the first and second sensing electrodes X1 to Xn and Y1 to Ym are not all the same. In addition, the reference value is different according to different driving signals.

In one embodiment, the self-capacitance measurement in step S10 uses the first driving signal TX1 shown in FIG. 7A, and the waveform of the control signal for controlling the switch SW ₂ is shown in FIG. 7B. The mutual capacitance measurement in step S20 uses the second driving signal TX2 shown in FIG. 7C, and the waveform of the control signal for controlling the switch SW ₂ is shown in FIG. 7D. The first driving signal TX1 has a first frequency f1, which is 500 KHz in FIG. 7A. The second driving signal TX2 has a second frequency f2. In FIG. 7C, the second frequency f2 is 2 MHz. See FIG. 7B and 7D, the control signal is 1 when the switch SW ₂ is turned on, when the control signal is 0, switch SW ₂ is turned off. The length of time each time the switch SW ₂ is turned on is the first period RT1. The first period RT1 can be understood as the length of time for sensing a first (or second) sensing electrode. During this first period RT1, the sensing circuit 221 senses the first or second sensing electrode. After the switch SW _{2 is} turned off, the sample-and-hold circuit 222 obtains an output voltage, which is used to calculate the inductance. By performing the above driving and sensing procedures on the first sensing electrodes X1~Xn and the second sensing electrodes Y1~Ym, the first X-axis sensing information dV_Self_X and the first Y-axis sensing information dV_Self_Y can be obtained. The second period RT2 can be understood as the length of time for sensing a sensing point 100. During this second period RT2, the sensing circuit 221 senses a sensing point 100. After the switch SW _{2 is} turned off, the sample-and-hold circuit 222 obtains an output voltage, which is used to calculate the inductance of the sensing point 100. By driving and sensing all the sensing points 100, the sensing quantities of all the sensing points 100 can be obtained.

In other embodiments, the first frequency f1 may be greater than, equal to or less than the second frequency f2. The length of the first period RT1 may be greater than, equal to or less than the length of the second period RT2. In an embodiment, the second frequency f2 is above 1 MHz, such as any frequency in the range of 1 MHz to 2 MHz. In the second period, RT2 is less than or equal to 0.28125us, for example, between 0.28125us and 0.09375us. Generally speaking, the higher the frequency of the driving signal, the shorter the corresponding sensing time. When performing mutual capacitance measurement, the higher the frequency of the second driving signal TX2, or the shorter the length of RT2 in the second period, the smaller the mutual capacitance induction caused by the liquid, which in turn makes a first or second sensing electrode The difference between the sum of the self-capacitance induction amount and the mutual-capacitance induction amount becomes larger, and the present invention uses this characteristic to determine whether there is liquid.

In other embodiments, after determining that liquid is present on the capacitive touch panel 10, the controller uses the second driving signal TX2, or other higher frequency driving signals, to perform Mutual capacitance measurement, and based on the sensing information obtained by the mutual capacitance measurement, calculate the position of a contact object. After a certain period of time, the above liquid detection method is performed again to confirm whether there is still liquid on the touch panel 10.

It can be understood from the above description that when a finger touches the liquid on the touch panel, the method according to the present invention can recognize the presence of the liquid. The above is only an embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field of the art, Within the scope of not departing from the technical solution of the present invention, when the technical contents disclosed above can be used to make some modifications or modifications to equivalent embodiments of equivalent changes, but any content that does not depart from the technical solution of the present invention, based on the technical essence of the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (27)

A liquid detection method on a capacitive touch panel, the capacitive touch panel includes a plurality of first sensing electrodes and a plurality of second sensing electrodes, the plurality of first sensing electrodes and the plurality of second sensing electrodes The intersection will constitute multiple sensing points; the liquid detection method includes the following steps: (a) performing self-capacitance measurement on the multiple first sensing electrodes to obtain first sensing information, the first sensing information including each of the first sensing information The sensing amount of the sensing electrode; (b) performing mutual capacitance measurement on the plurality of sensing points to obtain the sensing amount of each sensing point; (c) calculating the plurality of sensing points on each of the first sensing electrodes separately The second sensor information is obtained by the sum of the sensing quantities of and; and (d) According to the first sensor information and the second sensor information, it is determined whether liquid exists on the capacitive touch panel. The liquid detection method according to claim 1, wherein the self-capacitance measurement in step (a) includes simultaneously driving a plurality of the first sensing electrodes. The liquid detection method according to claim 1, wherein the step (d) includes: (d1) normalizing the second sensing information according to the first sensing information to obtain a third sensing information; (d2 ) Subtracting the third sensing information from the first sensing information to obtain a plurality of first differences; (d3) comparing the plurality of first differences with a critical value to determine the difference greater than the critical value The number of values; and (d4) According to the number obtained in step (d3), determine whether there is liquid on the capacitive touch panel. The liquid detection method according to claim 3, wherein the normalization operation in the above step (d1) is to multiply all values of the second sensing information by a ratio; wherein the denominator of the ratio is the value of the second sensing information The maximum value, the numerator of the ratio is the inductance of the first sensing electrode corresponding to the maximum value. According to the liquid detection method of claim 1, the mutual capacitance measurement in the step (b) includes sensing each of the sensing points for a second period, the length of the second period is less than or equal to 0.28125us. The liquid detection method according to claim 5, wherein the self-capacity measurement in step (a) includes sensing each first sensing electrode for a first period, and the length of the second period is less than or equal to The length of the first period. The liquid detection method according to claim 1, wherein the mutual capacitance measurement in step (b) includes driving each of the sensing points with a second driving signal having a second frequency, the second frequency being greater than or equal to 1 MHz. The liquid detection method according to claim 7, wherein the self-capacity measurement in step (a) includes driving each of the first sensing electrodes with a first driving signal having a first frequency, the second frequency is greater than Or equal to the first frequency. The liquid detection method according to claim 7, wherein after step (d) determines that liquid exists on the capacitive touch panel, the controller drives each sensing point with a driving signal greater than or equal to the second frequency The mutual capacitance measurement is performed to obtain the position of a contact object. A controller for detecting whether liquid exists on a touch panel, the touch panel includes a plurality of first sensing electrodes and a plurality of second sensing electrodes, the plurality of first sensing electrodes and the plurality of second sensing electrodes The intersection constitutes multiple sensing points; the controller includes: a storage medium for storing the firmware program; a processor coupled to the storage medium, the processor executes the following steps by executing the firmware program: ( a) Perform self-capacitance measurement on the plurality of first sensing electrodes to obtain first sensing information, the first sensing information includes the inductance of each of the first sensing electrodes; (b) Perform mutual interaction on the plurality of sensing points Capacitance measurement to obtain the inductance of each of the sensing points; (c) Calculate the sum of the inductances of each of the plurality of sensing points on each of the first sensing electrodes to obtain a second sensing information; and (d) According to the first sensing information and the second sensing information, it is determined whether liquid exists on the capacitive touch panel. The controller according to claim 10, wherein the self-capacitance measurement in step (a) includes driving a plurality of the first sensing electrodes simultaneously. The controller according to claim 10, wherein the step (d) includes: (d1) normalizing the second sensing information according to the first sensing information to obtain a third sensing information; (d2) Subtracting the third sensing information from the first sensing information to obtain a plurality of differences; (d3) comparing the plurality of differences with a threshold to determine the number of the differences greater than the threshold; and ( d4) According to the quantity obtained in step (d3), determine whether there is liquid on the capacitive touch panel. The controller according to claim 12, wherein the normalization operation in the above step (d1) is to multiply all values of the second sensing information by a ratio; wherein the denominator of the ratio is the maximum value in the second sensing information Value, the numerator of the ratio is the inductance of the first sensing electrode corresponding to the maximum value. According to the controller described in claim 10, the mutual capacitance measurement in step (b) includes sensing each sensing point for a second period, and the length of the second period is less than or equal to 0.28125 us. The controller according to claim 14, wherein the self-capacity measurement in the step (a) includes sensing each first sensing electrode for a first period, and the length of the second period is less than or equal to the first The length of a period. The controller according to claim 14, wherein the mutual capacitance measurement in step (b) includes driving the sensing points with a second driving signal having a second frequency, the second frequency being greater than or equal to 1 MHz. The controller according to claim 16, wherein the self-capacity measurement in step (a) includes driving each of the first sensing electrodes with a first driving signal having a first frequency, the second frequency is greater than or Is equal to the first frequency. The controller according to claim 16, wherein after step (d) determines that liquid is present on the capacitive touch panel, the controller uses a driving signal higher than or equal to the second frequency to drive the sensing points The mutual capacitance measurement is performed to obtain the position of a contact object. A liquid detection method for a capacitive touch panel. The capacitive touch panel includes a plurality of first sensing electrodes in the X direction and a plurality of second sensing electrodes in the Y direction. The plurality of first sensing electrodes and the The intersection of the plurality of second sensing electrodes constitutes a plurality of sensing points; the liquid detection method includes the following steps: (a) performing self-capacitance measurement on the plurality of first sensing electrodes and the second sensing electrode to obtain the first X-axis sensing Information and first Y-axis sensing information, the first X-axis sensing information includes the sensing amount of each of the first sensing electrodes, and the first Y-axis sensing information includes the sensing amount of each of the second sensing electrodes; (b) Perform mutual capacitance measurement on the multiple sensing points to obtain the inductance of each of the sensing points; (c) Calculate the sum of the inductances of the multiple sensing points on each of the first sensing electrodes to obtain a first Two X-axis sensing information, and separately calculating the sum of the sensing amounts of each of the plurality of sensing points on each second sensing electrode to obtain second Y-axis sensing information; and (d) according to the first X-axis sensing information and The first Y-axis sensing information, the second X-axis sensing information, and the second Y-axis sensing information determine whether liquid exists on the capacitive touch panel. The liquid detection method according to claim 19, in the above step (a), the self-capacitance measurement performed on the plurality of first sensing electrodes includes simultaneously driving a plurality of the first sensing electrodes, and The self-capacitance measurement performed by the second sensing electrode includes simultaneously driving a plurality of the second sensing electrodes. The liquid detection method according to claim 19, wherein the step (d) includes: (d1) normalizing the second X-axis sensing information according to the first X-axis sensing information to obtain a third X Axis sensing information, and based on the first Y axis sensing information, normalize the second Y axis sensing information to obtain a third Y axis sensing information; (d2) subtract the first X axis sensing information from the The third X-axis sensing information obtains a plurality of first X-axis difference values, and subtracts the third Y-axis sensing information from the first Y-axis sense information to obtain a plurality of first Y-axis difference values; (d3) respectively Comparing the plurality of first X difference values and the plurality of first Y axis difference values with a threshold value to determine the number of the first X difference value and the second Y axis difference value greater than the threshold value; and (d4) According to the quantity obtained in step (d3), determine whether liquid exists on the capacitive touch panel. The liquid detection method according to claim 21, wherein in the above step (d1): normalizing the second X-axis sensing information is to multiply all values of the second X-axis sensing information by a first ratio , Where the denominator of the first ratio is the maximum value in the second X-axis sensing information, and the numerator of the first ratio is the inductance of the first sensing electrode corresponding to the maximum value in the second X-axis sensing information And normalizing the second Y-axis sensing information is to multiply all values of the second Y-axis sensing information by a second ratio, where the denominator of the second ratio is the second Y-axis sensing information The maximum value, the numerator of the second ratio is the inductance of the second sensing electrode corresponding to the maximum value in the second Y-axis sensing information According to the liquid detection method described in claim 19, the mutual capacitance measurement in step (b) includes sensing each of the sensing points for a second period, and the length of the second period is less than or equal to 0.28125us. The liquid detection method according to claim 23, wherein the self-capacity measurement in step (a) includes sensing each of the first sensing electrodes and each of the second sensing electrodes for a first period, the The length of the second period is less than or equal to the length of the first period. The liquid detection method according to claim 19, wherein the mutual capacitance measurement in step (b) includes driving each of the sensing points with a second driving signal having a second frequency, the second frequency being greater than or equal to 1 MHz. The liquid detection method according to claim 25, wherein the self-capacity measurement in step (a) includes driving each of the first sensing electrodes and each of the second with a first driving signal having a first frequency For the sensing electrode, the second frequency is greater than or equal to the first frequency. The liquid detection method according to claim 25, wherein after step (d) determines that liquid is present on the capacitive touch panel, the controller uses a drive signal greater than or equal to the second frequency to drive the sensing points The mutual capacitance measurement is performed to obtain the position of a contact object.

Images