TW201523370A - Touch trace detecting device, system and method thereof - Google Patents

Abstract

The present invention provides a touch trace detecting method for preventing interruption of touch trace when suffering noise jamming. The detecting method comprises changing frequency of driving signals in response to noise detected; setting a plurality of lines of first sensing signal values generated from a first sensing as a plurality of baselines; computing a plurality of difference values between a plurality of lines of second sensing signal values and respective the plurality of baselines; determining whether all of the plurality of difference values are smaller than a threshold; determining whether the flatness of the plurality of baselines are larger than a flatness threshold if all of the difference values are smaller than the threshold; and reporting a first approximating or touching event happened before the changing of frequency if the flatness of the plurality of baselines are larger than the flatness threshold.

Description

Touch track detecting device, system and method thereof

The present invention relates to touch technology, and in particular to a touch technology in which the electromagnetic compatibility of noise is Class A.

Electronic products emit electromagnetic waves that interfere with other electronic products and are also subject to electromagnetic interference from other electronic products or electrical systems. Therefore, the production designer of electronic products must consider the electromagnetic compatibility (EMC) of electronic products. Electromagnetic compatibility generally refers to the extent to which electromagnetic waves that are inadvertently generated, propagated, and received cause electromagnetic interference (EMI) to the outside world, or the extent to which external electromagnetic waves cause electromagnetic interference to electronic products.

Touch screens are often one of the important human-machine interfaces for electronic products. In general, the touch screen has a relatively large area of sensing electrodes, and the detection principle of the touch screen is to detect the weak current on the sensing electrodes. Therefore, the touch screen is relatively sensitive to external electromagnetic interference. For example, external electromagnetic interference may affect the sensing electrode by the human body or the stylus approaching or touching the touch screen, or via the power line. The electromagnetic energy transmitted from other I/O cables causes the sensing electrodes to be affected. Noise

The electromagnetic compatibility of electronic products can be classified by the user's experience. When the noise occurs, if the user does not notice any noise, the electromagnetic phase of the electronic product for noise Capacitance can be referred to as Class A. When the noise occurs, if the user finds the influence of the noise, but after the noise disappears and the user returns to the normal use experience, the electromagnetic compatibility of the electronic product for the noise can be called It is Class B.

In the current capacitive touch screen, a plurality of driving electrodes are usually required to emit a driving wave, and a plurality of sensing electrodes exposed from a plurality of driving electrodes are detected. The driving wave described above has a certain operating frequency, and the timing of detection and sampling on the sensing electrode also corresponds to the operating frequency. When external electromagnetic interference affects the sensing electrode with the human body or the stylus, or via a power line or other I/O cable, the interference wave usually also has a certain frequency.

When a plurality of driving electrodes do not emit a driving wave, the sensing electrodes can be used to detect external interference waves. When the frequency of the interference wave is close to, equidistant, or mutually resonant with the operating frequency, the detection and sampling of the driving wave emitted by the sensing electrode to the driving electrode will be subject to very serious synchronous interference. Therefore, the capacitive touch screen must change the operating frequency of the driving wave emitted by the plurality of driving electrodes, so that the frequency of the interference wave is no longer close, equal, or not mutually resonant with the operating frequency.

At least two situations may occur after changing the operating frequency of the drive wave. One is that the value sensed by the sensing electrode changes, causing the detected position to change. The second is that the sensing electrode stops reporting the contact point during the change of the operating frequency. Assuming that the user changes the operating frequency of the driving wave while drawing the straight line with the finger, it is possible that the drawn line segment is interrupted and the line segment is discontinuous, so that the user originally intended to achieve the job fails. Although the user will succeed in drawing the line segment again, that is, the user returns to the normal use experience, that is, the electromagnetic compatibility for the noise is Class B.

In general, in order to meet a better user experience, there is no need for a pair in the market. The electromagnetic compatibility of the noise is an A-level capacitive touch device.

In one embodiment, the present invention provides a method for detecting a touch panel, comprising: after detecting a noise, changing a working frequency, performing a first sensing on the plurality of sensing electrodes to obtain a plurality of strips Sensing the signal value and setting the plurality of reference values; setting the flatness of the plurality of first sensing signal values to a false reference value; and performing the second sensing on the plurality of sensing electrodes And obtaining a plurality of second sensing signal values; determining, according to the plurality of reference values and the plurality of second sensing signal values, whether a second proximity event exists; and when the second proximity event does not exist, determining one Whether the proximity event flag is set; when the proximity event flag is set, determining whether a false reference value exists; and when there is a false reference value, reporting a first proximity event corresponding to the proximity event flag.

In another embodiment, the present invention provides a touch detection device for detecting a proximity event on a touch panel. The touch detection device includes a driving electrode connection interface for connecting to a plurality of driving electrodes on the touch panel, and driving the plurality of driving electrodes at a voltage of a working frequency; a sensing electrode connection interface, And a plurality of sensing electrodes connected to the touch panel, and receiving a plurality of sensing signal values of the plurality of sensing electrodes; and a control module connected to the driving electrode connection interface and the sensing electrode Connection interface. The touch detection device is configured to perform the steps described above.

In one embodiment, the present invention includes a touch detection system including the above touch panel and touch detection device.

In an embodiment, a method for detecting a touch track is provided for preventing a touch track from being broken during noise interference. The detection method includes: changing the driver after detecting the noise The frequency of the signal; the plurality of first sensing signal values obtained after the first sensing are set to a plurality of reference values; and the plurality of second sensing signal values obtained after the second sensing are respectively calculated and the plurality of a plurality of difference values of the reference value; determining whether the plurality of difference values are less than a threshold value; and when the plurality of difference values are less than the threshold value, determining whether the flatness of the plurality of reference values is greater than a flatness threshold And returning a first proximity event before changing the frequency of the drive signal when determining that the value is greater than the flatness threshold.

In another embodiment, a touch track detecting device is provided for preventing a touch track from being broken during noise interference, and is used to perform the above steps.

In a further embodiment, a touch track detection system is provided for preventing a touch track from being broken during noise interference. The detection system comprises: a touch panel comprising a plurality of driving electrodes and a plurality of sensing electrodes; and a detecting device connected to the plurality of driving electrodes and the plurality of sensing electrodes for performing the above steps.

One of the main spirits of the present invention is that after detecting the noise and changing the working frequency, when the proximity object remains on the touch panel and the correct reference value cannot be obtained, the old proximity event is returned for the user to feel. There is no impact of noise on the touch detection system.

110‧‧‧Signal volume

120‧‧‧Signal volume

190‧‧‧ position

210‧‧‧Signal volume

220‧‧‧Signal volume

320‧‧‧Signal volume

390‧‧‧ position

420‧‧‧Signal volume

510~565‧‧‧Steps

600‧‧‧Touch Detection System

610‧‧‧Touch panel

612‧‧‧ drive electrode

614‧‧‧Sensor electrode

620‧‧‧Touch detection device

622‧‧‧Drive electrode connection interface

624‧‧‧Sensor electrode connection interface

626‧‧‧Control Module

710~760‧‧‧Steps

The first figure is a schematic diagram of the amount of signal sensed by the sensing electrode at the first operating frequency.

The second figure is a schematic diagram of the amount of signal sensed by the sensing electrode at the second operating frequency.

The third figure is a schematic diagram of the amount of signal sensed by a sensing electrode after a proximity object moves at the second operating frequency.

The fourth picture is the signal sensed when a sensing electrode leaves the proximity sensor at the second operating frequency. A schematic diagram of the quantity.

The fifth figure is a schematic flowchart of a method of reporting a point according to an embodiment of the invention.

FIG. 6 is a schematic diagram of a touch detection system according to an embodiment of the invention.

FIG. 7 is a schematic flow chart of a method of reporting a point according to another embodiment of the present invention.

The invention will be described in detail below with some embodiments. However, the scope of the present invention is not limited by the embodiments, except as to the disclosed embodiments, which are subject to the scope of the claims. In order to provide a clearer description and to enable those skilled in the art to understand the present invention, the various parts of the drawings are not drawn according to their relative sizes, and the ratio of certain dimensions or other related scales may be highlighted. It is exaggerated to come out, and the irrelevant details are not completely drawn, in order to simplify the illustration.

Referring to the first figure, the horizontal axis represents the direction in which a certain sensing electrode extends, and the vertical axis represents the amount of signal sensed by the sensing electrodes. In one embodiment, the strip sensing electrodes and the plurality of driving electrodes have a plurality of intersection points, and by driving the plurality of driving electrodes one by one, the signal values of the respective intersection points can be sequentially obtained through the sensing electrodes. In another embodiment, the horizontal axis may also indicate the direction in which a certain drive electrode extends. Similarly, the strip driving electrode and the plurality of sensing electrodes have a plurality of intersection points, and the vertical axis represents the amount of signals sensed by the plurality of sensing electrodes at the respective intersection points. One of ordinary skill in the art can understand that the direction of the signal amount obtained by the two embodiments is the direction in which the sensing electrode or the driving electrode extends, and the two are generally orthogonal. Either way, the amount of sensing signal obtained can be applied to the embodiments described below.

The horizontal line 110 indicates that when one of the driving electrodes of the touch screen is driven at the first operating frequency, the amount of signals obtained by sensing by the plurality of sensing electrodes serves as a reference value. (baseline or stray). The uniformity (or flatness) of the horizontal line 110 must meet certain conditions in order to be a true reference value. The amount of signal referred to in the present invention may be directly measured by the amount of electrical change sensed by the sensing electrode, or may be reduced by the difference in the amount of electrical change sensed by the adjacent sensing electrode. Alternatively, the difference between the difference in the amount of electrical change sensed by the adjacent sensing electrodes may be reduced, and the present invention does not limit where the signal value comes from.

The amount of signal sensed by the sensing electrodes at the first operating frequency is a curve 120 with a protrusion at a portion centered at position 190. The touch screen can calculate a large capacitance change at the position 190 by comparing the difference between the curve 120 and the horizontal line 110, so that it is found that there is a conductive object approaching or contacting at the position 190 (referred to as a proximity). ) Touch screen.

When the touch screen detects that the frequency of the external interference wave is close to, equal to, or is mutually resonant with the first working frequency before the next round of scanning, the driving of the driving electrode in the next round of scanning is determined. The frequency of the wave changes to the second operating frequency to avoid severe interference from external interference waves. Before the next round of scanning, the flag of the proximity event is set because the proximity object is detected.

Referring to the second figure, when the second round is scanned at the second operating frequency, since the operating frequency has changed, the old reference value 110 corresponding to the first operating frequency must be updated. However, at this time, the external close-up object remains on the touch screen, so the amount of signal obtained by the second round of scanning is curve 210. Although the uniformity of the curve 210 is significantly non-uniform at location 190, curve 210 is the result of the first scan below the second operating frequency, so curve 210 can only be used as a reference value corresponding to the second operating frequency. However, due to the poor uniformity, the reference value represented by curve 210 is questioned. This reference value can be referred to as a false reference value or a special reference value.

When the touch screen continues to scan at the second operating frequency, the curve 220 is obtained. Sensing knot. Compared with the curve 210, the capacitance variation of the curve 220 is almost uniform, and the difference between the two is not compared, so that the proximity object is not detected. The proximity object on the touch screen cannot be detected regardless of the sensed value of each point of the sensing electrode, the difference between adjacent sensing values, and/or the difference between the adjacent sensing values. . However, the touch screen will check if the flag of the proximity event is set, and/or calculate the flatness of the curve 220. When the flag of the proximity event is set, and the flatness of the curve 220 is flawed, the touch screen can directly report the false point when the proximity of the object is not detected according to the difference between the curves obtained by the two rounds of scanning. For example, repeating the position 190, or reporting the false point with the estimated position of the close object. If the proximity object is a human finger, since the fingertip itself will cover a part of the screen, repeating the position 190 as a false point will not affect the user experience, and will not interrupt the connection of the proximity event. Therefore, this method can make the touch screen and its electronic products classify the noise into A grade, that is, the user does not feel any noise.

As the proximity object continues to move over the touch screen, gradually moving away from position 190 and moving to another location, the results of the scan are shown in Figure 3. When the protruding portion of the new scan curve 320 is gradually shifted from the curve 210 of the false reference value, since the peak of the signal value which is different from the curve 210 by the curve 320 is moved away from the position 190, it can be determined by the points of the sensing electrode. The difference between the sensed value, the difference between the adjacent sensed values, and/or the difference between the adjacent sensed values detects that the proximity object on the touch screen is in the new position 390.

Since at the time of the report, the false point is first reported at or near the position 190, then the new point is reported at the new position 390, and since the flag of the proximity event is set, the state representing the proximity event is continuous, so the position 190 will be The false point is wired to a new point in position 390 so that the connection of the proximity event is continuous. This method allows the touch screen and its electronic products to classify the noise as Class A, that is, the user does not feel any noise. When there is a new detection location 390, it is connected to After the corresponding position of the event flag is different, the proximity event flag can be cleared.

When the proximity object leaves the position away from the touch screen at position 190, the result of the scan is shown in the fourth figure. Since the proximity object is near the surface of the touch screen, the amount of signal scanned is a nearly straight horizontal line 420. Since the difference between the horizontal line 420 and the false reference value curve 210 near the position 190 is a negative value, and the flatness of the horizontal line 420 is not defective. Therefore, the touch screen replaces the false reference value curve 210 with the false reference line 210 as a new reference value, and stops the false negative point, that is, the proximity object has left the touch screen, and the proximity event flag is cleared. This method allows the touch screen and its electronic products to classify the noise as Class A, that is, the user does not feel any noise.

In some embodiments, the touch screen not only takes the horizontal line 420 corresponding to a certain sensing electrode as a new reference value, but also uses the sensing values of all the sensing electrodes as the entire touch screen in the second work. The new reference value at the frequency. In other words, the replacement reference value may be updated one by one by sensing the electrodes, or the reference value of each of the sensing electrodes may be updated. Especially in the case of multi-finger touch, it is suitable to adopt the method of sensing the electrodes one by one, so as not to affect the other false objects of the close objects that have not left the touch screen.

The 平 calculation of the above flatness can compare the difference between two adjacent points of a certain sensing electrode with the threshold value. When the difference is greater than the threshold value, the flatness of the signal value of the sensing electrode can be regarded as defective. It is also possible to compare the difference between the corresponding two points of the adjacent two sensing electrodes with the threshold value. When the difference between the difference between the corresponding two points of the adjacent two sensing electrodes is greater than the threshold value, the flatness of the signal values of the two electrodes may be regarded as being 瑕疵. The above three threshold values may be the same or different.

In some cases, when the signal value of any one of the sensing electrodes is flat, In case of 瑕疵, it can be considered that the flatness of the signal value of the entire touch screen is flawed. When the flatness of the signal value of any two adjacent second electrodes is flawed, it may also be that the flatness of the signal value of the entire touch screen is flawed. Alternatively, in some cases, the flatness may be limited to the sensing electrode or the adjacent two sensing electrodes.

Please refer to the fifth figure, which is a schematic flowchart of a method for reporting a point according to an embodiment of the present invention. Reference may be made to the foregoing description of the first to fourth figures. The premise of implementing this method is to detect the noise, and decide to change the working frequency when the close object is on the touch screen.

Step 510: Set a proximity event flag.

Step 515: Scan after changing the working frequency. The signal value obtained by this scan may be curve 210.

Step 520: Set the curve 210 with flatness to be a false reference value.

Step 525: Scan to obtain a new signal value, which may be the curve 220 of the second figure, the curve 320 of the third figure, or the horizontal line 420 of the fourth figure.

Step 530: It is determined that the proximity event is detected. When the proximity event is detected, the new signal value obtained in step 525 may be the curve 320 of the third graph, so step 535 is continued. When the proximity event is not detected, the new signal value may be the curve 220 of the second figure or the horizontal line 420 of the fourth figure, so step 540 is performed.

Step 535: After detecting the proximity event, the proximity event flag set in step 510 can be cleared and a new point is reported.

Step 540: Determine whether a proximity event flag is set. When the proximity event flag has been set, the process proceeds to step 555, otherwise step 550 is performed.

Step 550: When a proximity event is not detected and the proximity event flag is not set, There is no need to report. When the process proceeds to step 550, the touch screen may have entered a normal state.

Step 555: Determine whether the new signal value has a flatness 瑕疵. If yes, go to step 560, otherwise go to step 565.

Step 560: When the proximity event is not detected, and the flag has been set, and the new signal value has a flatness, then a false point needs to be reported. As shown in the second figure.

Step 565: When the proximity event is not detected, and the flag has been set, and the new signal value has no flatness, as in the example of the fourth figure. You can replace the old false reference value with the new signal value, clear the proximity event flag, and do not need to report.

After the above steps 535, 550, 560, and 565 are completed, step 525 can be performed again.

Please refer to the sixth figure, which is a schematic diagram of a touch detection system 600 according to an embodiment of the invention. The touch system 600 includes a touch panel 610 and a touch detection device 620. The touch detection device 620 is configured to detect a proximity event on the touch panel 610. The touch panel 610 includes a plurality of driving electrodes 612 and a plurality of sensing electrodes 614. The touch detection device 620 includes a driving electrode connection interface 622 for connecting to the plurality of driving electrodes 612 on the touch panel 610, and driving the plurality of driving electrodes 612 with a voltage of a certain operating frequency. The touch detection device 620 includes a sensing electrode connection interface 624 for connecting to the plurality of sensing electrodes 614 on the touch panel 610 and receiving a plurality of sensing signals of the plurality of sensing electrodes 614. .

The touch detection device 620 further includes a control module 626 connected to the driving electrode connection interface 622 and the sensing electrode connection interface 624. The control module 626 is configured to perform the following steps: after detecting the noise, changing the working frequency, performing the first sensing on the plurality of sensing electrodes to obtain a plurality of first sensing signal values, and setting a plurality of benchmark values; a flatness value of a sensed signal value is set as a false reference value; the plurality of sensing electrodes are subjected to a second sensing to obtain a plurality of second sensing signal values; and according to the plurality of reference values The plurality of second sensing signal values determine whether a second proximity event exists; when the second proximity event does not exist, determining whether a proximity event flag is set; when the proximity event flag is set, determining Whether there is a false reference value exists; and when there is a false reference value, a first proximity event corresponding to the proximity event flag is reported.

In addition to the steps described above, the control module 626 can also implement the other embodiments described above, particularly the flowcharts shown in FIG. 5, as well as various possible variations thereof.

Please refer to the seventh figure, which is a schematic flowchart of a method of reporting according to another embodiment of the present invention. Reference may be made to the foregoing description of the first to sixth figures. The premise of implementing this method is to detect the noise, and decide to change the working frequency when the close object is on the touch screen. As with the embodiment shown in the sixth figure, the control module 626 can perform the embodiment shown in the seventh figure and various modifications thereof in addition to the reporting method shown in the fifth figure.

Step 710: After detecting the noise, change the frequency of the driving signal.

Optional step 715: setting the proximity event flag and the first proximity event corresponding thereto.

Step 720: Set the plurality of first sensing signal values obtained after the first sensing to a plurality of reference values.

Step 730: Calculate a plurality of difference values between the plurality of second sensing signal values obtained after the second sensing and the plurality of reference values.

Step 740: Determine whether the plurality of differences are less than a threshold.

Step 750: When the plurality of differences are less than the threshold, determining the complex number Whether the flatness of the reference value is greater than a flatness threshold.

Optional step 755: When it is determined that the value is greater than the flatness threshold, it is determined whether a proximity event flag is set.

Step 760: Rewarding a first proximity event prior to changing the frequency of the drive signal.

In an embodiment, the optional steps 715 and 755 described above may not be performed. In another embodiment, the optional steps 715 and 755 described above may be performed. After performing step 755, step 760 is to report the first proximity event corresponding to the proximity event flag when the proximity event flag is set.

In one embodiment, the flatness is greater than at least one of the sensing electrodes corresponding to the flatness threshold, and the corresponding difference is less than the threshold.

As shown in the third embodiment, the method of the seventh figure further includes calculating a second proximity event based on the at least one difference when at least one of the differences is greater than the threshold; and reporting the second proximity event . If the proximity event flag is set, the method of the seventh figure further includes clearing the proximity event flag.

One of the main spirits of the present invention is that after detecting the noise and changing the working frequency, when the close object remains on the touch panel and the correct reference value cannot be obtained, the old close-up object is returned for the user to feel. There is no impact of noise on the touch detection system.

710~760‧‧‧Steps

Claims (18)

A touch track detection method for preventing a touch track from being disconnected during noise interference, comprising: changing a frequency of a driving signal after detecting a noise; and obtaining a plurality of pieces after the first sensing The first sensing signal value is set as a plurality of reference values; respectively calculating a plurality of difference values between the plurality of second sensing signal values obtained after the second sensing and the plurality of reference values; determining whether the plurality of differences are All are less than a threshold value; when the plurality of differences are less than the threshold value, it is determined whether the flatness of the plurality of reference values is greater than a flatness threshold; and when the judgment is greater than the flatness threshold, the reward is changed to drive A first proximity event before the frequency of the signal. The method for detecting a touch track according to claim 1 further includes: determining whether a proximity event flag is set when determining that the value is greater than the flatness threshold; and when the proximity event flag is set, Retrieving the first proximity event corresponding to the proximity event flag. For the method for detecting a touch track according to the second aspect of the patent application, the step of changing the frequency of the driving signal further includes: setting the proximity event flag and the first proximity event corresponding thereto. The method for detecting a touch track according to claim 1 , wherein at least one of the sensing electrodes whose flatness is greater than the flatness threshold value is smaller than the threshold value. The method for detecting a touch track according to claim 1, further comprising: calculating, when at least one of the differences is greater than the threshold, calculating a second proximity event according to the at least one difference; and reporting the second Close incident. The method for detecting a touch track according to item 5 of the patent application scope further includes: clearing a proximity event flag. A touch track detecting device for preventing a touch track from being broken during noise interference, for performing the following steps: changing the frequency of the driving signal after detecting the noise; after the first sensing The obtained plurality of first sensing signal values are set to a plurality of reference values; respectively calculating a plurality of difference values between the plurality of second sensing signal values obtained after the second sensing and the plurality of reference values; determining the plural Whether the difference is less than a threshold; when the plurality of differences are less than the threshold, determining whether the flatness of the plurality of reference values is greater than a flatness threshold; and when determining that the threshold is greater than the flatness threshold , returning a first proximity event before changing the frequency of the drive signal. For example, the detecting device of claim 7 is used to perform the following steps: When it is determined that the value is greater than the flatness threshold, it is determined whether a proximity event flag is set; and when the proximity event flag is set, the first proximity event corresponding to the proximity event flag is reported. The detecting device of claim 8 is further configured to set the proximity event flag and the first proximity event corresponding thereto when the frequency step of the driving signal is changed. The detecting device of claim 7, wherein the at least one sensing electrode corresponding to the flatness is greater than the threshold value, and the corresponding difference is less than the threshold value. The detecting device of claim 7 is further configured to: when at least one of the differences is greater than the threshold, calculate a second proximity event according to the at least one difference; and report the second Close incident. For example, the detecting device of claim 11 is further used to perform the following steps: clearing a proximity event flag. A touch track detecting system for preventing a touch track from being broken during noise interference, comprising: a touch panel comprising a plurality of driving electrodes and a plurality of sensing electrodes; and a detecting device connected to The plurality of driving electrodes and the plurality of sensing electrodes are configured to perform the following steps: After detecting the noise, changing a frequency of the driving signals of the plurality of driving electrodes; and determining, by the plurality of sensing electrodes, the plurality of first sensing signal values obtained by the first sensing; Calculating, respectively, a plurality of difference values between the plurality of second sensing signal values obtained by the plurality of sensing electrodes and the plurality of reference values; and determining whether the plurality of differences are less than a threshold value; When the plurality of differences are less than the threshold value, determining whether the flatness of the plurality of reference values is greater than a flatness threshold; and when the judgment is greater than the flatness threshold, returning a value before changing the frequency of the driving signal A close incident. The detecting system of claim 13 , wherein the detecting device is further configured to: when determining that the value is greater than the flatness threshold, determine whether a proximity event flag is set; and when the proximity event When the flag is set, the first proximity event corresponding to the proximity event flag is reported. The detection system of claim 14, wherein the detecting device is further configured to set the proximity event flag and the first proximity event corresponding thereto when the frequency step of the driving signal is changed. For example, in the detection system of claim 13, wherein the flatness is greater than the flatness threshold Corresponding at least one of the sensing electrodes, the corresponding difference is less than the threshold value. The detection system of claim 13 , wherein the detecting device is further configured to: when at least one of the differences is greater than the threshold, calculate a second proximity event based on the at least one difference And returning the second proximity event. For example, in the detection system of claim 17, wherein the detecting device is further configured to perform the following steps: clearing a proximity event flag.