TWI763859B - Sensing method of touch recognition device and sensing module thereof - Google Patents

Abstract

A sensing method of a touch identification device, wherein the touch identification device includes a node where a sensing electrode and a driving electrode intersect, and the sensing method includes: selecting a first sensing electrode and setting it to reverse measurement, and intersecting with the driving electrode to have a first node; driving more than one driving electrode, and measuring the first sensing electrode to obtain a first measurement value of the first node, and then measuring other sensing electrodes other than the first sensing electrode electrode to obtain the point measurement value of the node; compare the variation value of each point measurement value on the same driving electrode with the first measurement value; check whether the variation value is higher or lower than the threshold value; if so, then It is judged that the sensing electrode on the measured value of the point is abnormal; and when at least one variation value is higher than or lower than the threshold value, the touch measurement is stopped.

Description

Sensing method of touch recognition device and sensing module thereof

The present invention relates to a sensing method of a touch recognition device and a sensing module thereof, and in particular, to a sensing method and a sensing module thereof for judging whether there is foreign matter on the touch recognition device when a touch signal is read, to Improve overall sensing accuracy.

The touch panel or touch screen is one of the main modern human-machine interfaces. As a position recognition device, it can skillfully combine the input and display interface, so it has the advantages of saving device space and humanized operation. It has been widely used in All kinds of consumer or industrial electronic products. Examples: personal digital assistant (PDA), palm-sized PC, tablet computer, mobile phone, Information Appliance, Point-Of -Sale, POS) and other devices.

The existing capacitive touch panel includes a data processing module, driving electrodes and sensing electrodes, etc., wherein the driving electrodes and the sensing electrodes are electrically connected to the data processing module through their respective interfaces. The driving electrodes are composed of a plurality of parallel driving electrode strips, and the sensing electrodes are composed of a plurality of mutually parallel sensing electrode strips, wherein each driving electrode strip and each sensing electrode strip are arranged perpendicular to each other to form a plurality of intersections . When the driving electrode is driven by the driving voltage, an electric field is formed between it and the sensing electrode, so that the sensing electrode generates an induced charge and has an interactive capacitance. A plurality of driving electrode strips and a plurality of sensing electrode strips form a plurality of electric fields, so It can be simulated that each intersection has an interactive capacitor, and a plurality of intersections form an array of interactive capacitors. In a stable environment, the interactive capacitor array has a stable capacitance (hereinafter referred to as the base capacitor), so that the sensing electrode generates an induced voltage (the induced voltage at this time is called the base voltage), and the data processing module reads through its interface. Take the induced voltage. When a finger or other conductive material approaches the intersection, it will change the electric field there, causing the induced voltage to change. After the changed induced voltage is transmitted to the data processing module, it is converted into a digital signal by an analog-to-digital converter, and then it is identified by an algorithm whether it is a touch signal, and whether to perform the calculation of the touch position is processed and formed. Input data to the touch information output from the host. The host end is a device controlled by at least one central processing unit (CPU), such as a computer, a PDA, and the like.

Since the electric field formed between the driving electrode and the sensing electrode is easily disturbed by external electromagnetic waves, etc., it is impossible to accurately measure the change in the amount of charge transferred by capacitive charging caused by conductive substances such as fingers. Therefore, in the prior art, there is a method of subtracting this noise by means of signal subtraction, which repeats a measurement cycle to obtain two or more different sensing voltage signals and then subtract them. Two or more different sensing voltage signals are processed by a differential method to obtain a touch signal that eliminates common mode noise. Although the general differential method can eliminate the background noise, it needs two pairs of sensing signals to calculate the differential value, which may cause foreign objects to touch during the measurement process, resulting in a decrease in accuracy or resolution.

In view of the above-mentioned background of the invention, the embodiments of the present invention provide a sensing method of a touch recognition device and a sensing module thereof, which execute a judgment program periodically or instantaneously during the general periodic wave difference comparison operation of the sensing method. In this way, it can be judged whether there is foreign matter on the touch recognition device when the touch signal is read, and the sensing method and the sensing module thereof can eliminate the noise signal, so as to improve the overall sensing accuracy.

In order to achieve one or part or all of the above objectives or other objectives, an embodiment of the present invention provides a sensing method for a touch recognition device, wherein the touch recognition device includes a plurality of sensing electrodes and a plurality of driving electrodes, wherein a plurality of A plurality of sensing electrodes intersect with a plurality of driving electrodes to have a plurality of nodes. The sensing method includes the following steps: selecting a first sensing electrode among the plurality of sensing electrodes, and setting the first sensing electrode as an inverse amount measurement, wherein the first sensing electrode and a plurality of driving electrodes intersect to have a plurality of first nodes; one or more driving electrodes are driven, and the first sensing electrodes are measured to obtain a first node of one or more first nodes a measurement value, and then measure other sensing electrodes other than the first sensing electrode to obtain a plurality of point measurement values of a plurality of nodes; compare each point measurement value on the same driving electrode with the first measurement value respectively a variation value of the measured value; check whether the variation value is higher or lower than a threshold value; if the variation value is higher or lower than the threshold value, the sensing electrode on which the measured value of the point is determined is abnormal; and, When at least one variation value is higher or lower than the threshold value, a touch measurement is stopped.

In one embodiment, the touch measurement is stopped when the number of the sensing electrodes determined to be abnormal is at least two.

In one embodiment, if the variation value is not higher or lower than the threshold value, or the number of abnormal sensing electrodes is less than two, touch measurement is performed.

In one embodiment, the step of obtaining the first measurement value and the plurality of point measurement values further includes: driving one or a part of the plurality of driving electrodes; measuring the first sensing electrodes to obtain one or more The first measurement values of one or more first nodes, and then simultaneously or sequentially measure other sensing electrodes other than the first sensing electrodes to obtain one or a part of the measurement values of a plurality of points; stop driving ; drive the other or the rest of the plurality of drive electrodes; measure the first sensing electrodes to obtain first measurement values of one or more first nodes, and then simultaneously or sequentially measure the first sensing electrodes to obtain the other or the rest of the plurality of point measurement values; and repeating the above driving operation to obtain all the plurality of point measurement values and the plurality of first measurement values.

In one embodiment, the step of obtaining the first measurement value and the plurality of point measurement values further includes: simultaneously driving all of the plurality of driving electrodes; and measuring the first sensing electrodes to obtain all the first nodes The first measurement value of , and other sensing electrodes other than the first sensing electrode are simultaneously measured, so as to obtain all the measurement values of a plurality of points.

In one embodiment, the method further includes: selecting another one of the plurality of sensing electrodes as the first sensing electrode, so as to set the first sensing electrode as reverse measurement.

In one embodiment, the step of setting the first sensing electrode for reverse measurement includes electrically connecting the first sensing electrode to a reverse measurement circuit, or a processing unit will pass through the measurement cycle in this measurement cycle. The signal received by the first sensing electrode is processed in reverse. The touch measurement further includes: electrically connecting the rest of the plurality of sensing electrodes to a positive vector measurement circuit, and performing touch measurement to obtain a touch signal. The step of touch measurement includes: the reverse measurement circuit and the forward measurement circuit perform measurement in sequence, and obtain a reverse signal and a forward signal synchronously respectively; and receive the reverse signal through an analog digital conversion circuit. The signal and the forward signal are converted to obtain a touch signal, wherein the phase signals of the forward signal and the reverse signal are shifted by 180 degrees.

In one embodiment, if the variation value is higher than the threshold value, it is determined that a pointing object touches the first sensing electrode.

In one embodiment, if the variation value is lower than the threshold value, it is determined that a non-pointing object touches the first sensing electrode.

In order to achieve one or part or all of the above purposes or other purposes, an embodiment of the present invention provides a sensing module of a touch recognition device, comprising: a plurality of sensing electrodes, including a first sensor configured for reverse measurement a sensing electrode; a plurality of driving electrodes, intersecting with the sensing electrodes to have a plurality of nodes, and intersecting with the first sensing electrodes to have a plurality of first nodes; and a processing unit electrically connected to the plurality of driving electrodes and a plurality of sensing electrodes for driving one or more driving electrodes, measuring the first sensing electrodes to obtain a first measurement value of one or more first nodes, and measuring other than the first sensing electrodes other sensing electrodes to obtain a plurality of point measurement values of a plurality of nodes; wherein the processing unit compares each point measurement value on the same driving electrode with a variation value of each first measurement value; the processing unit Check whether the variation value is higher or lower than a threshold value; if the variation value is higher or lower than the threshold value, the processing unit judges that the sensing electrode on the measured value of the point is abnormal; and when at least one variation quality is higher than or equal to the threshold value or below the threshold value, the processing unit stops a touch measurement. Wherein, if the variation value is not higher or lower than the threshold value, or the number of abnormal sensing electrodes is less than two, the processing unit performs touch measurement.

100, 200‧‧‧Sensing module

110, 210‧‧‧processing unit

120(D1-D7), 220(225A-225D)‧‧‧driving electrodes

130(S1-S4), 230(S1-S7)‧‧‧Sensing electrodes

FIG. 1 is a schematic diagram of a sensing module applied to a touch recognition device according to a first embodiment of the present invention.

FIG. 2 is a flowchart of a sensing method applied to a touch recognition device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram of a sensing module applied to a touch recognition device according to the first embodiment of the present invention.

FIG. 4 is a schematic diagram of a sensing module applied to a touch recognition device according to a second embodiment of the present invention.

The foregoing and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or rear, etc., are only used to refer to the directions of the accompanying drawings. Therefore, these directional terms are only used to illustrate and not to limit the present invention.

Please refer to FIG. 1 , which is a sensing module 100 of a touch recognition device according to a first embodiment of the present invention. A sensing module 100 of a touch recognition device includes a processing unit 110 , a plurality of driving electrodes 120 and a plurality of sensing electrodes 130 . In this embodiment, the driving electrodes 120 include at least seven driving electrodes D1-D7, and the sensing electrodes 130 include at least four sensing electrodes S1-S4. The plurality of driving electrodes 120 and the plurality of sensing electrodes 130 intersect to have a plurality of nodes D1S1 , D1S2 , D1S3 , D1S4 , D2S1 , D2S2 . . . and so on. The processing unit 110 is electrically connected to the sensing electrodes 130 and the driving electrodes 120 for driving the driving electrodes 120 and sensing capacitance changes on the sensing electrodes 130 to obtain a plurality of point measurement values of a plurality of nodes.

The above-mentioned sensing module 100 is used to execute a sensing method of a touch recognition device in the following embodiments of the present invention.

Please refer to FIG. 2 , which is a schematic flowchart of a sensing method of a touch recognition device according to an embodiment of the present invention, and is described with reference to FIGS. 3 and 4 . The sensing method according to the embodiment of the present invention includes the following steps S100-S700 to execute a judgment procedure and to perform touch measurement.

Step S100: Select a first sensing electrode among the plurality of sensing electrodes S1-S4. In this embodiment, the sensing electrode S1 is preselected as the first sensing electrode, and the sensing electrode S1 is set to be used for reverse measurement. The first sensing electrode S1 intersects with a plurality of driving electrodes D1-D7 to have a plurality of first nodes D1S1, D2S1, D3S1 . . . and so on. The step of setting the sensing electrode S1 as the reverse measurement includes electrically connecting the sensing electrode S1 to a reverse measurement circuit, so that the processing unit 110 can use the first sensing electrode in this measurement cycle. The signal received by S1 is processed in reverse, for example, multiplied by a minus sign, so as to save operation time.

Step S200 : Drive one or more driving electrodes, measure the first sensing electrodes to obtain the measurement value of one or more first nodes, and then measure other sensing electrodes other than the first sensing electrodes to obtain Plural point measurements of other pluralities of nodes. In this embodiment, the point measurement value of the plurality of nodes or the first node measurement value is the variation value generated by the periodic wave driving.

In one embodiment, the step of obtaining the first measurement value and the plurality of point measurement values further includes: driving one or a part of the driving electrodes; measuring the first sensing electrodes to obtain one or more than one The first measurement value of the first node, and then simultaneously or sequentially measure other sensing electrodes other than the first sensing electrode to obtain one or a part of the measurement values of a plurality of points; stop driving; drive The other or the rest of the plurality of driving electrodes; measuring the first sensing electrodes to obtain first measurement values of one or more first nodes, and simultaneously or sequentially measuring other than the first sensing electrodes other sensing electrodes to obtain the other or the rest of the plurality of point measurement values; and, repeating the above driving operation to obtain all the point measurement values and the first measurement value.

In the first embodiment, as shown in FIG. 3 , the driving electrode D1 is driven first to obtain point measurement values of different nodes D1S1 , D1S2 , D1S3 , and D1S4 in sequence, including a first measurement value of the first node D1S1 . Next, the driving electrode D2 is sequentially driven in the direction of the arrow to obtain point measurement values of different nodes D2S1 , D2S2 , D2S3 , and D2S4 , including the first measurement value of the first node D2S1 . Then, the driving electrodes D3 and D4 are sequentially driven to obtain the point measurement values of all nodes D3S1, D3S2, D3S3, D3S4, D4S1, D4S2, D4S3, and D4S4.

FIG. 4 is a sensing module 200 of a touch recognition device according to a second embodiment of the present invention. The sensing module 200 includes a processing unit 210 , a plurality of driving electrodes 220 and a plurality of sensing electrodes 230 . The processing unit 210 is electrically connected to the sensing electrodes 230 and the driving electrodes 220 . In this embodiment, the driving electrodes 220 are divided into four parts, which are the first part of the driving electrodes 225A-225D, and the sensing electrodes 230 include at least seven sensing electrodes S1-S7. A plurality of driving electrodes 220 and a plurality of sensing electrodes 230 intersect to have a plurality of nodes, and the sensing electrode S1 is still selected as the first sensing electrode. In the second embodiment, the first part of the driving electrode 225A is driven first, and the point measurement values of different nodes 225AS1, 225AS2, 225AS3, etc. are sequentially obtained, including a first measurement value of the first node D1S1. . Next, the second portion of the driving electrodes 225B, the third portion of the driving electrodes 225C, and the fourth portion of the driving electrodes 225D are driven in sequence following the direction of the arrows to obtain point measurement values of all nodes.

In the above-mentioned embodiments of this step S200, the present invention is not limited to obtaining all the point measurement values and the first measurement values in this step, and one or a part of the driving electrodes may be driven first, and then After obtaining the first measurement value of the first sensing electrode and the point measurement value of a plurality of nodes of one or a part of the sensing electrode, the next steps S300-S400 can be continued, and then go back to step S200 to Obtain all point measurement values and the first measurement value.

In one embodiment, referring to FIG. 3 again, the driving electrode D1 is driven for the first time to obtain point measurement values of different nodes D1S1, D1S2, D1S3, and D1S4 in sequence, including a first value of the first node D1S1. measured value. Then, following the direction of the big black arrow, the driving electrode D4 is directly jumped for the second time to obtain point measurement values of different nodes D4S1, D4S2, D4S3, and D4S4, including the first measurement value of the first node D4S1. Then, continue to jump to drive other drive electrodes. Among them, the second driving can directly select the driving electrode D4, that is, the distance from the first driving driving electrode D1 is separated by 3 driving electrodes; 4-5 driving electrodes D5 or D6 are used to speed up the response time of the sensing method.

In another embodiment, the step of obtaining the first measurement value and the plurality of point measurement values further includes: simultaneously driving all of the plurality of driving electrodes; and measuring the first sensing electrodes to obtain all the first The first measurement value of the node, and other sensing electrodes other than the first sensing electrode are simultaneously measured to obtain all the measurement values of the plurality of points.

Step S300: Comparing the measured value of each point on the same driving electrode with a variation value of the first measured value. In the first embodiment shown in FIG. 2, in step S200, after driving the driving electrode D1, the first measurement value of the first node D1S1 and the variation values of the other nodes D1S2, D1S3, and D1S4 are sequentially obtained, respectively, Then go to step S400; or after driving the driving electrode D2 again, sequentially obtain the variation values of the first measurement value of the first node D2S1 and the other nodes D2S2, D2S3, D2S4, and go to step S400.

Step S400: Check whether the variation value obtained in step S300 is higher or lower than a threshold value set by the sensing module. The measurement value sensed by the above-mentioned sensing electrodes is the variation generated by the periodic wave driving, and the difference between the two is compared by using steps S300-S400. When a non-pointing object such as a finger or a stylus touches the sensing module, if the sensing module needs to determine whether there is another foreign object touching, it will compare the periodic wave drive variation attenuation, because the sensing measurement value will be The attenuation is caused by non-pointing objects such as touch or other foreign objects (such as water stains), so the above steps are to observe and determine whether the attenuation is caused by non-pointing objects. If the variation value is higher than the threshold value, it is determined that a pointing object touches the first sensing electrode. If the variation value is lower than the threshold value, it is determined that a non-pointing object touches the first sensing electrode.

Step S500: If the variation value is higher or lower than the threshold value, it is determined that the sensing electrode on which the measurement value of the point is located is abnormal. As shown in FIG. 3 , since the variation values of the nodes D1S2 and D4S3 and the first nodes D1S1 and D4S1 respectively are higher or lower than the threshold value, it is determined that the sensing electrodes S2 and S3 are both abnormal. As shown in FIG. 4 , since the variation values between the node regions 225AS2 and 225CS4 and the first nodes 225AS1 and 225CS1 are higher or lower than the threshold value, it is determined that the sensing electrodes S2 and S4 are both abnormal.

Step S600: Continue to step S500, and stop a touch measurement when at least one variation value is higher or lower than the threshold value. In a preferred embodiment, when the number of the sensing electrodes determined to be abnormal is at least two, the touch measurement is stopped.

When judging that the first sensing electrode is touched by a finger or has a foreign object on it, the previously obtained measurement value signal of the node is used to overwrite the old read point measurement value with the newly read point measurement value; Or you can directly discard the old point measurement value and not use it.

Step S700: Continuing from Step S600, select another one of the plurality of sensing electrodes as the first sensing electrode and set it to reverse measurement. The above steps S100-S600 are repeated to re-execute the judgment procedure.

The judgment procedure of the above-mentioned sensing method can adopt periodic detection or instant detection. If periodic detection is used, after several touch measurements are performed, the judgment procedure is performed once to scan the full panel to confirm whether the sensing electrodes selected as reverse measurement are appropriate; if immediate detection is used, then The judgment is made after each periodic wave variation attenuation under touch measurement is compared. Each time a node signal is obtained for periodic wave variation attenuation comparison, the variation value is first determined according to the conditions set by the touch system to determine whether the first sensing electrode used as the reverse measurement is touched, and then other signal processing or judgment is performed, such as Report points.

Step S510 : Continuing with step S400 , if the variation value is not higher or lower than the threshold value, or the number of abnormal sensing electrodes is less than two, perform touch measurement. In this embodiment, in addition to electrically connecting the sensing electrode S1 to a reverse measurement circuit, the touch measurement further includes: electrically connecting the rest of the plurality of sensing electrodes to a forward measurement circuit, and A touch signal is obtained by performing touch measurement. The step of performing the touch measurement includes: the reverse measurement circuit and the forward measurement circuit perform measurement in sequence, and respectively obtain a reverse signal and a forward signal synchronously; and receive the reverse signal through an analog-to-digital conversion circuit The signal and the forward signal are converted to obtain a touch signal, wherein the phase signals of the forward signal and the reverse signal are shifted by 180 degrees.

Embodiments of the present invention provide a sensing method of a touch recognition device and a sensing module thereof. By periodically or instantaneously executing a judgment program in the periodic wave variation attenuation comparison operation of the sensing method, the touch control can be judged. A sensing method and a sensing module for the presence or absence of foreign objects on a touch recognition device during signal reading to improve the overall sensing accuracy.

S100-S700‧‧‧Steps

Claims (13)

A sensing method of a touch recognition device, wherein the touch recognition device includes a plurality of sensing electrodes and a plurality of driving electrodes, wherein the plurality of sensing electrodes and the plurality of driving electrodes intersect to have a plurality of nodes, and the sensing The detection method includes the following steps: selecting a first sensing electrode in the plurality of sensing electrodes, and setting the first sensing electrode as reverse measurement, wherein the first sensing electrode and the plurality of driving electrodes There are a plurality of first nodes intersected to form a plurality of first nodes. The step of setting the first sensing electrode to reverse measurement includes electrically connecting the first sensing electrode to a reverse measurement circuit, and electrically connecting the plurality of sensing electrodes. The rest of the measurement electrodes are sent to a positive vector measurement circuit; one or more of the driving electrodes are driven, and the first sensing electrodes are measured to obtain a first measurement value of one or more of the first nodes, and then measuring the other sensing electrodes other than the first sensing electrode to obtain a plurality of point measurement values of the plurality of nodes; comparing each point measurement value on the same driving electrode with the first A variation value of the measurement value; check whether the variation value is higher or lower than a threshold value; if the variation value is higher or lower than the threshold value, determine the sensing point on the measurement value The electrodes are abnormal; and when at least one of the variation values is higher or lower than the threshold value, a touch measurement is stopped. The sensing method of claim 1, wherein the number of the sensing electrodes determined to be abnormal is at least two, and the touch measurement is stopped. The sensing method as described in item 1 of the claimed scope, wherein if the variation value is not higher or lower than the threshold value, or the number of the sensing electrodes that are abnormal is less than two, the sensing is performed. Control measurement. The sensing method as described in claim 1, wherein the step of obtaining the first measurement value and the plurality of point measurement values further comprises: driving one or a part of the plurality of driving electrodes ; measure the first sensing electrode to obtain the first measurement value of one or more of the first nodes, and then simultaneously or sequentially measure the other sensing electrodes other than the first sensing electrode to obtain One or a part of the plurality of point measurement values; stop driving; drive the other or the rest of the plurality of driving electrodes; measure the first sensing electrode to obtain one or more of the first The first measurement value of a node, and then simultaneously or sequentially measuring the other sensing electrodes other than the first sensing electrode to obtain the other or the rest of the plurality of point measurement values; and , and repeat the above driving action to obtain all the plurality of point measurement values and the plurality of first measurement values. The sensing method as described in claim 1, wherein the step of obtaining the first measurement value and the plurality of point measurement values further comprises: simultaneously driving all of the plurality of driving electrodes; and, measuring the first sensing electrode to obtain the first measurement value of all the first nodes, and at the same time The other sensing electrodes other than the first sensing electrode are measured to obtain all the measurement values of the plurality of points. The sensing method as described in claim 1, further comprising: selecting another one of the plurality of sensing electrodes as the first sensing electrode, so as to set the first sensing electrode as an inverse amount Measurement. The sensing method as described in claim 1, wherein the step of setting the first sensing electrode to reverse measurement includes a processing unit in which the first sensing electrode will receive the signal received through the first sensing electrode during the measurement cycle. The signal is processed in reverse. The sensing method according to claim 3, wherein the touch measurement step comprises: the reverse measurement circuit and the forward measurement circuit perform measurements in sequence, and obtain a reverse signal synchronously respectively. and a forward signal; and receiving the reverse signal and the forward signal through an analog digital conversion circuit to convert to obtain a touch signal, wherein the phase signal of the forward signal and the reverse signal is 180 degrees offset. The sensing method according to claim 1, wherein if the variation value is higher than the threshold value, it is determined that a pointing object touches the first sensing electrode. The sensing method of claim 1, wherein if the variation value is lower than the threshold value, it is determined that a non-pointing object touches the first sensing electrode. A sensing module of a touch recognition device, comprising: A plurality of sensing electrodes, including a first sensing electrode set for reverse measurement, wherein the first sensing electrode is electrically connected to a reverse measurement circuit, and the rest of the plurality of sensing electrodes are electrically connected connected to a positive vector sensing circuit; a plurality of driving electrodes intersecting with the plurality of sensing electrodes to have a plurality of nodes, and a plurality of first nodes intersecting with the first sensing electrodes; and a processing unit, electrically connecting the plurality of driving electrodes and the plurality of sensing electrodes for driving one or more driving electrodes, and measuring the first sensing electrodes to obtain a first measurement value of one or more first nodes, Then measure other sensing electrodes other than the first sensing electrode to obtain a plurality of point measurement values of the plurality of nodes; wherein, the processing unit compares each of the point measurement values on the same driving electrode respectively. with a variation value of each of the first measurement values; the processing unit checks whether the variation value is higher or lower than a threshold value; if the variation value is higher or lower than the threshold value, the processing unit Determining that the sensing electrode on the measurement value at the point is abnormal; and, when at least one of the aberrations is higher or lower than the threshold value, the processing unit stops a touch measurement. The sensing module of claim 11, wherein if the variation value is not higher or lower than the threshold value, or the number of abnormal sensing electrodes is less than two, the processing The unit performs the touch measurement. The sensing method of claim 12, wherein the processing unit performing the touch measurement comprises: The reverse measurement circuit performs measurements in sequence with the forward measurement circuit to obtain a reverse signal and a forward signal synchronously, respectively; and receives the reverse signal and the forward signal through an analog-to-digital conversion circuit , to convert the touch signal to obtain the touch signal, wherein the phase signal of the forward signal and the reverse signal are shifted by 180 degrees.

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