CN110058722B - A method for judging touch events in a touch detection system - Google Patents

Abstract

The invention discloses a method for judging a touch event in a touch detection system. The method includes transmitting at least one driving signal to a touch screen of the touch detection system; receiving from the touch screen corresponding to the at least one driving signal A sensing signal of the signal; performing a digital initial judgment on the sensing signal to determine whether a touch event occurs; judging whether the sensing signal is disturbed by a noise signal; and when judging that the touch event occurs or When it is judged that the sensing signal is interfered by the noise signal, a complete judgment is performed on the sensing signal. Through the above method, the effect of reducing time consumption and power consumption can be achieved.

Description

A method for judging touch events in a touch detection system

The filing date of the original application is May 22, 2015, the application number of the original application is 201510267094.3, and the invention name of the original application is "method for judging touch events in a touch detection system".

technical field

The present invention relates to a method for judging a touch event in a touch detection system, in particular to a method for judging a touch event in a touch detection system through digital initial judgment.

Background technique

In recent years, touch sensing technology has developed rapidly, and many consumer electronic products such as mobile phones, GPS navigator systems, tablets, personal digital assistants (PDAs) and notebook computers (laptop), etc. have built-in touch function. In the above-mentioned various electronic products, the area of the original display panel is given a touch sensing function, that is, the original simple display panel is converted into a touch display panel with a touch recognition function. According to the difference in the structural design of the touch screen, it can generally be divided into an out-cell and an in-cell/on-cell touch screen. Among them, the external touch screen is composed of an independent touch screen and a general display panel, while the in-cell touch screen directly disposes the touch sensing device on the inner or outer side of the substrate in the display panel.

Touch sensing technology can be divided into resistive, capacitive and optical. Capacitive touch screen has gradually become the mainstream of the market due to its advantages of high sensing accuracy, high light transmittance, fast response speed and long service life. In a general capacitive touch detection system, a plurality of capacitors are arranged on the touch screen or the screen for touch detection. Existing touch detection often needs to perform a complete judgment to determine whether a touch event occurs, where the touch occurs, and the intensity of the touch. For example, when a touch event occurs, the touch control module can perform an interpolation operation on the sensing signals from different capacitances on the touch screen to determine the location where the touch occurs. In the above manner, the value of each sensing signal can be obtained to determine the intensity of the touch received at each position on the touch screen, thereby achieving accurate touch determination. The above method takes a long time and consumes more power in the touch detection system.

In addition, there is often noise (eg, liquid crystal module noise (LCM noise)) in the sensing signal, and the noise will reduce the report rate of the touch event. In order to obtain a better reporting rate, the existing noise detection and error correction methods often use powerful filters to filter out the noise. However, powerful filters usually have narrower bandwidths to control the passage of certain signals, but narrower bandwidths correspond to longer time consumption in the time domain. In addition, the touch control module can also perform complex analog operations on the sensing signals to eliminate or reduce interference caused by noise.

However, the above-mentioned complete judgment mechanism often requires a complicated circuit design, consumes more power and consumes more time, thereby reducing the efficiency of the touch detection system. In view of this, it is necessary to propose a better solution for signal processing and operation of the touch sensing signal, so as to improve the efficiency of the touch detection system.

SUMMARY OF THE INVENTION

Therefore, the main purpose of the present invention is to provide a method for judging touch events in a touch detection system through digital initial judgment, thereby realizing the advantages of reducing time and power consumption in the touch detection system.

The invention discloses a method for judging touch events in a touch detection system. The method for judging a touch event includes transmitting at least one driving signal to a touch screen of the touch detection system; receiving a sensing signal corresponding to the at least one driving signal from the touch screen; a digital initial judgment to judge whether a touch event occurs; judge whether the sensing signal is disturbed by a noise signal; and when it is judged that the touch event occurs or the sensing signal is disturbed by the noise signal , and perform a complete judgment on the sensing signal.

Description of drawings

FIG. 1 is a schematic diagram of waveforms of judging a touch event through a sensing signal.

FIG. 2 is a schematic diagram of touch events on a touch screen.

FIG. 3 is a schematic diagram of a touch detection process according to an embodiment of the present invention.

4A and 4B are schematic diagrams illustrating non-uniform sampling of a sensing signal disturbed by a regular noise signal.

FIG. 5 is a line graph of the normalized error of the sampling result of the sensing signal disturbed by noise.

FIG. 6 is a schematic diagram of a touch screen according to an embodiment of the present invention.

FIG. 7 is a schematic diagram of the data distribution of the touch screen when it is driven.

FIG. 8 is a schematic diagram of an operation manner in which the touch control module performs the digital preliminary judgment and the complete judgment according to the embodiment of the present invention.

FIG. 9 is a schematic diagram of another operation manner in which the touch control module performs the digital preliminary judgment and the complete judgment according to the embodiment of the present invention.

FIG. 10 is a schematic diagram of an operation manner in which the touch control module performs a series of digital judgments and recombines the sum signal according to an embodiment of the present invention.

Among them, the reference numerals are described as follows:

TH threshold

20, 600 touch screen

30 Touch Detection Process

300～312 steps

L1, L2 curve

702, 704, 706 areas

TX_1～TX_M drive lines

RX_1～RX_N sense lines

Y1～Ym drive signal

X1～Xn sensing signal

TS1～TSn sub-interval

C11～CMn Capacitance value generated by touch gesture

N11 ~ NMn noise signal

RX Sum_1～RX Sum_n, A1～A4, sum signal

B1～B4, C1～C4, D1～D4

TX Sum_1～TX Sum_M, NF, SA, SB, SC, sum

SD, SA’, SB’, SC’, SD’

Detailed ways

As mentioned above, the existing complete judgment method is time-consuming and power-consuming, so it is necessary to propose a better method for touch detection, so as to judge the touch event in the touch detection system. Generally speaking, a touch control module of a touch detection system can transmit a driving signal to a capacitor on the touch screen, and receive a sensing signal from the capacitor to determine whether a touch event occurs, and can be preset for the sensing signal to be used for Determine a threshold value of the touch event.

Please refer to FIG. 1 . FIG. 1 is a schematic diagram of a waveform of determining a touch event through a sensing signal. FIG. 1 includes a threshold TH and a sensing signal. If the sensing signal is lower than the threshold TH, it can be determined that a touch event occurs; on the contrary, if the sensing signal is higher than the threshold TH, it means that no touch occurs on the touch screen.

As shown in FIG. 1 , if the sensing signal indicates the occurrence of a touch event, the sensing signal needs to have a high resolution. More specifically, the sensing signals should obtain accurate signal values, and different signal values of different sensing signals can be combined with each other to further determine touch information, such as the position and intensity of the touch event. In this case, a complete judgment is required to calculate the touch information. On the other hand, if the sensing signal indicates that the touch event has not occurred, the above-mentioned complete determination is not required. Further, in the case where the touch event is judged by the threshold value TH without further judgement, the sensing signal only needs low resolution. That is to say, since the above judgment includes only two judgment results, which can be represented by one bit, a simple operation is sufficient to handle this low-resolution judgment method. In this case, only when a touch event occurs, a full judgment at the required higher resolution needs to be performed.

Please refer to FIG. 2 , which is a schematic diagram of touch events on a touch screen 20 . As shown in FIG. 2 , touch events occur at two points on the touch screen 20 . Generally, touch events are often only detected at a single or a few locations on the entire touch screen, or even no touch events are detected at all. For most locations where no touch events occur, full resolution at high resolution is not required.

It can be seen that, from the perspective of time, within a period of time, the touch event only occurs in part of the time; from the perspective of space, the touch event only occurs in part of the entire touch screen. Therefore, in most of the time and most of the space, a low-resolution digitized preliminary judgment is sufficient for signal processing of the sensed signal, and a high-resolution full judgment is not required.

The digital preliminary judgment can use a simple circuit structure, which can reduce the power consumption and the required time consumption. However, the simplified digitized preliminary judgment will result in the degradation of the noise detection ability. Fortunately, US Patent Application Nos. 14/607,031 and 14/285,604 provide a method for noise detection that can be performed efficiently without the use of large filters, which include complex circuits and consume a lot of time. In addition, part of the regular noise can be eliminated or reduced by non-uniform sampling. These detection and noise reduction methods enable simple digital preliminary judgments to be implemented in touch detection systems.

Please refer to FIG. 3 , which is a schematic diagram of a touch detection process 30 according to an embodiment of the present invention. The touch detection process 30 can be implemented in any touch control module that can be used in various touch detection systems such as resistive, capacitive, or optical. The touch detection process 30 includes the following steps:

Step 300: Start.

Step 302: Send at least one driving signal to a touch screen of the touch detection system.

Step 304: Receive a sensing signal corresponding to the at least one driving signal from the touch screen.

Step 306: Perform a digital preliminary judgment on the sensing signal to judge whether a touch event occurs. If the touch event occurs, go to step 310; if not, go to step 308.

Step 308: Determine whether the sensing signal is disturbed by a noise signal. If yes, go to step 310; if not, go to step 312.

Step 310: Perform a complete judgment on the sensing signal.

Step 312: End.

According to the touch detection process 30, the touch control module transmits at least one driving signal to a touch screen of the touch detection system, and receives a sensing signal corresponding to the at least one driving signal from the touch screen. Next, the touch control module performs a digital preliminary judgment on the sensing signal to judge whether a touch event occurs. The initial digitization judgment can be accomplished by simply comparing the sensing signal with a threshold value (the threshold value TH as shown in FIG. 1 ) without additionally judging other touch information such as touch strength, signal magnitude and touch position. Therefore, in the step of performing the digital preliminary judgment, the touch control module will know whether a touch event occurs, but cannot obtain complete information about the touch event, such as the location where the touch event occurs.

If the comparison result of the digital preliminary judgment indicates that a touch event has occurred, the touch control module will then perform a complete judgment on the sensing signal to obtain complete touch information, and then judge the touch position and/or touch intensity. , more time-consuming high-resolution operations need to be performed. On the other hand, if the comparison result of the digital preliminary judgment indicates that no touch event has occurred, the touch control module will additionally judge whether the sensing signal is disturbed by a noise signal. If noise that interferes with the sensing signal is detected, the touch control module will also start a complete judgment for the sensing signal to eliminate or reduce noise interference, and then judge the touch position and/or touch intensity (if there is a touch) . If no noise is detected, the touch control module will not perform a complete judgment on the sensing signal. In this case, time and power consumption can be saved.

It can be seen from this that the complete judgment with higher resolution and time-consuming is only performed when it is judged that a touch event occurs or that the sensing signal is disturbed by a noise signal. In other words, if it is determined that the touch event does not occur and the sensing signal is not disturbed by the noise signal, it can be ignored without performing the complete determination.

Furthermore, as mentioned above, for a touch screen, full judgment is not required most of the time and most of the space. Therefore, compared with the prior touch control module that performs complete judgment on all received sensing signals, the present invention uses complete judgment only when the digital preliminary judgment indicates the occurrence of a touch event or the noise detection method indicates the presence of noise. In one embodiment, the complete decision may include a signal processing mechanism using large filters to filter or eliminate any possible noise. In another embodiment, the complete judgment may include a maximum likelihood calculation method for estimating the touch intensity corresponding to each sensing signal, so that the touch control module can accurately calculate the touch position and/or or touch strength. Compared with the digital initial judgment, the complete judgment (such as a large filter or a maximum likelihood operation) provides a higher-resolution touch judgment, and the operation time required is much longer than that required for the digital initial judgment. Therefore, in the touch detection process 30, reducing the number of times of using the complete judgment can achieve the advantages of reducing time consumption and power consumption.

It is worth noting that the sequence of step 306 and step 308 can be interchanged, that is, the touch control module can determine the occurrence of the touch event after determining whether the noise signal exists. In this case, if any one of the noise signal and the touch event occurs, a complete judgment can still be performed.

Generally speaking, the noise signal of the touch detection system can be divided into two types: regular noise and irregular noise. In order to avoid false touch points, both regular noise and irregular noise must be eliminated or reduced. Irregular noise can be processed by the noise detection methods described in US Patent Application Nos. 14/607,031 and 14/285,604, while regular noise can be eliminated by non-uniform sampling in the initial digitization process. Regular noise can be any type of noise generated by regular operations in an electronic system associated with the touch detection system, such as liquid crystal module noise (LCM noise) or liquid crystal display (LCD) systems Other man-made noises etc. For example, regular noise can be generated by a circuit device in a liquid crystal display system. When the circuit device generates a noise signal, it will send relevant information according to the time when the noise signal reaches the sensing line on the touch screen. Therefore, touch The detection system will know where in the sensed signal the disturbance of the regular noise exists.

Please refer to FIG. 4A and FIG. 4B . FIGS. 4A and 4B are schematic diagrams illustrating non-uniform sampling of a sensing signal disturbed by a regular noise signal. FIG. 4A shows that there are several regularly occurring noise signals on the sensing signal, and FIG. 4B shows the waveform of the same sensing signal after non-uniform sampling. As shown in FIG. 4A , the value of the sensing signal is approximately between -0.1 and 0.1, and the sensing signal is seriously disturbed by the noise signal, and the range of the noise signal can reach -1 to 1. It can be seen from FIG. 4A that the noise signal on the sensing signal obviously affects the judgment result of the touch event. According to the non-uniform sampling, before sampling the sensing signal, at least one segment of the sensing signal can be deleted, wherein the deleted segment is the part disturbed by regular noise. In other words, since the touch detection system knows where the noise interference occurs, the noise-disturbed part of the sensing signal can be eliminated by non-uniform sampling, as shown in FIG. 4B . Therefore, the touch detection system only samples the portion of the sensing signal that is not disturbed by noise.

It is worth noting that the existing signal processing mechanisms for complete judgment usually perform signal processing in the frequency domain, which often requires the use of powerful filters to eliminate noise signals. When powerful, it takes more time for signal processing. On the other hand, different from the existing complete judgment method, the digital initial judgment of the present invention adopts non-uniform sampling in the time domain to eliminate the interference of regular noise, and its implementation is relatively simple, which can take less time and use complexity Solve the noise problem in the case of lower circuit. For example, in one embodiment, non-uniform sampling can be implemented by a multiplexer having two input terminals, an output terminal, and a control terminal controlled by a control signal, wherein a The input terminal receives the sensing signal and the other input terminal receives zero potential. During the period when the sensing signal is disturbed by regular noise (eg time point A), the control signal can control the multiplexer to output zero potential; during the period when the sensing signal is not disturbed by regular noise (eg time point B), the control signal can control The multiplexer outputs the sensing signal. In other embodiments, the non-uniform sampling may also be implemented in other manners, but is not limited thereto.

Please refer to FIG. 5. FIG. 5 illustrates the advantages brought by the above-mentioned non-uniform sampling, which is a line graph of the normalized error of the sampling result of the sensing signal disturbed by noise, wherein a value of 1 represents an accurate The sampling results, and the values 1.1, 1.2, 1.3 and 1.4 represent that the errors of the sampling results of the sensing signals are 10%, 20%, 30% and 40%, respectively. The curve L1 corresponds to the sensing signal before non-uniform sampling is performed, and the curve L2 corresponds to the sensing signal after non-uniform sampling is performed. As shown in FIG. 5 , due to the interference of noise, the sampling result has an error of about 30% to 40%. After non-uniform sampling, the error can be greatly reduced to 0% to 5%. It can be seen that non-uniform sampling has a strong effect of reducing errors. In addition, since the error size is reduced to about one-eighth, the sensing signal can be amplified eight times before entering the analog-to-digital converter (ADC) of the touch control module, so that the analog-to-digital converter The dynamic range is improved by 3 bits, which in turn greatly improves the efficiency of the analog-to-digital converter.

The way in which non-uniform sampling works can be described by the following general equation:

Among them, R(t) represents the sensing signal, which can be divided into a signal component A×g(t) and a noise component noise(t), g(t) represents a basic signal, such as a basic sine wave or square wave, sequence(t) represents the remaining time sequence of the sensing signal after at least one segment is deleted, and the deleted segment is the part of the sensing signal disturbed by noise. As shown in the general equation, the sensing signal can be divided into signal components and noise components. Therefore, by selecting an appropriate sequence(t), the noise components can be effectively eliminated.

In addition, noise that cannot be eliminated by non-uniform sampling (eg, irregular noise) can be detected by the noise detection methods described in US Patent Application Nos. 14/607,031 and 14/285,604. Please refer to FIGS. 6 and 7 , wherein FIG. 6 is a schematic diagram of a touch screen 600 according to an embodiment of the present invention, and FIG. 7 is a schematic diagram of data distribution when the touch screen 600 is driven. As shown in FIG. 6 , the touch screen 600 includes a plurality of driving lines TX_1 to TX_M and a plurality of sensing lines RX_1 to RX_N for sensing touch gestures on the touch screen 600 , wherein M and N are positive integers greater than 1. A driving circuit of the touch screen 600 can transmit a plurality of driving signals Y1-Ym to the driving lines TX_1-TX_M in a time period having a specific time length, so as to drive the sensing lines RX_1-RX_N to generate a plurality of senses Measurement signals X1-Xn, where m and n are positive integers greater than 1.

Referring to FIG. 7 , the horizontal axis represents the time interval, the timing increases from left to right, and the vertical axis represents the driving direction of the touch screen 600 , which is scanned from the driving line TX_1 to the driving line TX_M sequentially from top to bottom. In this exemplary embodiment, the time interval includes a plurality of sub-intervals (time slots) TS1 ˜TSn. In the area 706, the data Cji+Nji indicated at the intersections of the driving lines TX_1-TX_M and the sensing lines RX_1-RX_N represent the sum of the capacitance value Cji generated by the touch gesture and the noise signal Nji generated by the touch screen 600 affected by the outside world, Among them, j is a positive integer from 1 to M, i is a positive integer from 1 to n, and M and n are positive integers greater than 1. The noise signal Nji may include various noises that cannot be eliminated by non-uniform sampling, such as irregular noise. In the area 704 , the sum signals RX Sum_1 ˜RX Sum_n indicated by the positions of the sensing lines RX_1 ˜RX_N in FIG. 6 represent that a touch control module calculates the signal values of the sensing signals X1 ˜Xn respectively during this time interval The sum obtained. That is to say, the sum signal RX Sum_i represents the sum of the data obtained by the sensing line RX_I from the driving lines TX_1 ˜TX_M in the sub-interval TSi of this time interval, where I is a positive integer from 1 to N. For example, the sum signal RX Sum_1 represents the sum of C11+N11 to CM1+NM1 in the sub-interval TS1 of this time interval. The sum signal RX Sum_1～RX Sum_n can be expressed by the following formula:

Among them, RX Sum_i represents the sum signal, Cji represents the capacitance value generated by the touch gesture, Nji represents the noise generated by the touch screen 600 affected by the outside world, where j is a positive integer from 1 to M, and i is a positive integer from 1 to n Integer, M and n are positive integers greater than 1.

In this exemplary embodiment, each of the driving signals Y1 ˜Ym has a first polarity pattern and a second polarity pattern. During this time interval, the calculation results of the first polarity pattern and the second polarity pattern of each of the driving signals Y1 - Ym are substantially zero. In this example, the operation of the first polarity pattern and the second polarity pattern of each driving signal Y1 ˜Ym can be summed up, that is, in the area 702 , corresponding to the The total sums TX Sum_1 to TX Sum_M of the driving signals Y1 to Ym indicated by the positions are respectively zero, which means that in this time interval, the sum of the first polarity pattern and the second polarity pattern of the driving signals Y1 to Ym is substantially zero.

For example, take four driving signals Y1-Y4 as an example. In this exemplary embodiment, in the time interval including the two sub-intervals TS1 and TS2, the polarity distribution states of the driving signals Y1-Y4 are shown in Table 1 below:

TX_1(Y1) TX_2(Y2) TX_3(Y3) TX_4(Y4) TS1 -1 1 1 -1 TS2 1 -1 -1 1

Table 1

In Table 1, "1" indicates that the driving signals Y1-Y4 have the first polarity pattern in the corresponding sub-interval, and "-1" indicates that the driving signals Y1-Y4 have the second polarity pattern in the corresponding sub-interval. Therefore, in the field of the driving line TX_1, after the time interval including the two sub-intervals TS1 and TS2 passes, the sum of the first polarity pattern and the second polarity pattern of the driving signal Y1 is substantially zero. The polarity distribution states of the driving signals Y2 ˜ Y4 of the driving lines TX_2 ˜ TX_4 can be deduced by analogy. In addition, the polarity distribution patterns of each of the driving signals Y1-Y4 are not limited to those shown in Table 1, and other examples are shown in US Patent Application Nos. 14/607,031 and 14/285,604, which will not be repeated here.

Please refer to FIG. 6 and FIG. 7 again, and in conjunction with the driving concepts disclosed in the embodiments of Table 1, the touch control module of the touch screen 600 can calculate the sum of the signal values of the sensing signals X1-Xn in a time interval of a specific time length, respectively. , to obtain the sum signal RX Sum_1~RX Sum_n. Next, the touch control module calculates the sum signal RX Sum_1~RX Sum_n again to obtain the sum NF of the sum signal RX Sum_1~RX Sum_n, that is,

The sum NF obtained by the touch control module calculating the sum signals RX Sum_1 ˜RX Sum_n represents the noise generated by the touch screen 600 affected by the outside world. Therefore, using the above-mentioned noise detection method, the noise signal generated by the external influence can be quickly and accurately estimated.

It can be seen from this that in the absence of noise, the sum of the first polarity pattern and the second polarity pattern of the driving signal is substantially zero, regardless of whether there is a touch event on the touch screen 600 . Therefore, if the sum NF is any non-zero value, it can be regarded as being disturbed by noise, and the noise signal can be detected by the above method. For example, step 308 of the touch detection process 30 can be implemented by the above-mentioned touch detection method, which obtains the sum NF to determine whether the sensing signal includes noise. If the sum NF is equal to zero, it can be judged that the sensing signal does not have any noise; if the sum NF is not equal to zero, it can be judged that the sensing signal is disturbed by the noise signal, and then the complete judgment is used to process the noise signal. In another embodiment, the touch control module may further preset a threshold value for the sum NF, and if the sum NF exceeds the threshold value, it can be determined that the sensing signal is disturbed by the noise signal.

Please refer to FIG. 8 . FIG. 8 is a schematic diagram of an operation manner of the touch control module performing the digital preliminary judgment and the complete judgment according to the embodiment of the present invention. As shown in FIG. 8 , the touch control module may arrange the time schedule to reserve a plurality of digitized judgment times for initial digitization judgment and a plurality of complete judgment times for complete judgment in an alternate manner within a certain period, wherein , each digitized judgment time in the plurality of digital judgment times is immediately before a complete judgment time in the plurality of complete judgment times. During each digitization judgment time, a digitization preliminary judgment and a noise detection method can be performed once. If the digital initial judgment or the noise detection method indicates that a complete judgment is required due to the occurrence of a touch event or noise interference, the touch control module will perform a complete judgment within the next complete judgment time (as shown in the first complete judgment time in Figure 8). Show). If the initial digitization judgment and the noise detection method respectively indicate that the touch event and noise interference have not occurred, so the complete judgment is not required, the touch control module will not execute the complete judgment within the next complete judgment time, and the touch control module will wait until the next digitization Judgment time, and then start to perform digital initial judgment (as shown in the second complete judgment time in Figure 8). In the above manner, the complete judgment is only performed in a small or part of the time, which can reduce power consumption. However, this scheduling method is relatively simple and cannot reduce time consumption. In other embodiments, when the complete judgment is not required, the next digital preliminary judgment may be directly performed to reduce time consumption.

It is worth noting that, in addition to the above-mentioned signal processing methods using large filters and maximum likelihood operations, the complete judgment can also be achieved through a series of digital judgments to achieve high resolution. More specifically, although a low-resolution touch detection can only be obtained by a single digital judgment, a high-resolution touch detection can still be achieved by performing a series of digital judgments.

For example, please refer to FIG. 9 . FIG. 9 is a schematic diagram of another operation manner in which the touch control module performs the digital preliminary judgment and the complete judgment according to the embodiment of the present invention. As shown in FIG. 9, a complete judgment may consist of four digital judgments that are the same or similar to the digital initial judgment. In this example, the touch control module can perform one or two digital determinations to determine whether a touch event occurs and whether the sensing signal is disturbed by noise. Other digital decisions are performed when necessary, ie, when a touch event or noise signal is detected. For example, in FIG. 9 , a complete judgment time includes four digitized judgment times, wherein each digitized judgment time can perform one digitized judgment. The touch control module can first perform digital judgment within the first and second digital judgment times, and determine whether to perform more digitization judgments according to the judgment results obtained during the first and second digitization judgment times. The judgment result obtained in each of the above-mentioned digital judgments indicates whether a touch event occurs and whether a noise signal exists, and the noise signal can be judged from the sum signal obtained from the sensing signal according to the above-mentioned noise detection method. If a touch event or a noise signal is detected, the touch control module may further perform digital determination in the third and fourth digital determination times to obtain touch position information with higher resolution and/or eliminate noise interference. On the other hand, if no touch events and noise signals are detected, the digitization judgments in the third and fourth digitization judgment times will not be performed.

Please continue to refer to FIG. 9 . FIG. 9 illustrates how a series of digital determination operations are combined with the above-mentioned noise detection method. In the third complete judgment time shown in FIG. 9 , the touch control module may first perform the digitization judgment in the first and second digitization judgment times, and judge that the judgment result of the second digitization judgment is disturbed by noise. In this case, the touch control module further performs digitization judgment in the third and fourth digitization judgment times. Next, the touch control module obtains four judgment results corresponding to the sensing signals of the four digital judgments, and judges whether the above judgment results are disturbed by noise signals. The touch control module may choose to use at least one of the above judgment results that is judged to be not disturbed by noise to judge the touch information related to the touch event, such as the touch position and the like. As shown in the third complete judgment time in FIG. 9 , the judgment results obtained in the second and third digitization judgments are disturbed by noise, and the touch control module therefore chooses to use the judgment results obtained in the first and fourth digitization judgments. Determine the occurrence and/or touch location of a touch event.

It is worth noting that, according to the noise detection method described in US Patent Application No. 14/607,031, the summation signals obtained in different time intervals can be recombined to obtain another summation NF' whose value is smaller than the original summation NF, and also That is, the sum signal corresponding to the sum NF' is less disturbed by noise than the sum signal corresponding to the sum NF. Please refer to FIG. 6 and FIG. 7 again. The touch control module can obtain the first summation signals A, B, C and D corresponding to the sensing lines RX_1 to RX_4 respectively, and the sum NF3 of the signal values of the first summation signals A, B, C and D within the first time interval (NF3=A+B+C+D) represents the noise signal value calculated by the touch control module after executing the first noise detection method. Next, the touch control module obtains the second summed signals A', B', C' and D' corresponding to the sensing lines RX_1 to RX_4 respectively in the second time interval, and the second summed signals A', B', C' The sum NF4 of the signal values of and D' (NF4=A'+B'+C'+D') represents the noise signal value calculated by the touch control module after executing the second noise detection method.

In this exemplary embodiment, the touch control module may use at least one of the second summation signals A', B', C' and D' to replace part or all of the first summation signals A, B, C and D, So that the sum NF5 of the signal values after the recombination by the second summation signals A', B', C' and D' and the first summation signals A, B, C and D is smaller than the sum of the signal values of the first summation signal before the recombination. Sum NF3. In the above manner, after performing any possible recombination of the summed signals, the best summed signal combination, ie the one least disturbed by noise, can be determined by finding the smallest summation. Compared with the method of removing the judgment results whose sum is not equal to zero, the method of reorganization and selection can more accurately judge the touch event and the touch position. It should be noted that, in the embodiment shown in FIG. 9 , although the summation of multiple summation signals is disturbed by noise, some or most of the summation signals included in the summation are still accurate. Therefore, these accurate sum signals can be combined with other accurate sum signals obtained in other time intervals by means of recombination. In this case, more valid data in the sum signals can be saved to obtain more accurate touch judgment.

Please refer to FIG. 10 . FIG. 10 is a schematic diagram of an operation manner in which the touch control module performs a series of digital judgments and recombines the sum signal according to an embodiment of the present invention. As shown in Figure 10, each large square represents a digital judgment time, which can be regarded as a time interval for generating a judgment result, wherein the judgment result can be obtained by four sum signals (such as sum signals A1-A4, B1-B4 , C1~C4 or D1~D4) are added together to indicate the sum. After the touch control module executes the digital judgment within the four digital judgment times, it can obtain the sums SA, SB, SC and SD corresponding to each digital judgment respectively, where SA is equal to the sum of the summation signals A1, A2, A3 and A4 , SB is equal to the sum of the summed signals B1, B2, B3 and B4, SC is equal to the sum of the summed signals C1, C2, C3 and C4, SD is equal to the sum of the summed signals D1, D2, D3 and D4. Next, the touch control module performs reorganization. For example, as shown in FIG. 10, the summation signals A1, B1, C1 and D1 can be combined with each other to obtain a summation SA', and the summation signals A2, B2, C2 and D2 can be combined with each other to obtain a summation SA'. The summation SB', the summation signals A3, B3, C3 and D3 can be combined with each other to obtain a summation SC', and the summation signals A4, B4, C4 and D4 can be combined with each other to obtain a summation SD'. More specifically, the touch control module may combine any number of the summed signals A1-A4, B1-B4, C1-C4, and D1-D4 to obtain the summation. In one embodiment, the touch control module may find the minimum sum to obtain four or any number of sum signals that are least disturbed by noise, and choose to use these sum signals to determine touch information, such as the occurrence of a touch event and/or or touch location, etc. On the other hand, the touch control module can find a sum less than a threshold value, and obtain the sum signal included in the sum(s), and then the touch control module can judge the touch information according to the sum signal. As shown in Figure 10, after several reorganizations, the touch control module can determine that the sum signals A2, A3, A4, B2, C1, C4, D1, D2 and D3 are not disturbed by noise, and choose to use these sum signals to judge Touch Info. In this case, optimal touch information can be obtained by choosing to take all the sum signals that are not disturbed by noise, and exclude all sum signals that are disturbed by noise.

To sum up, the present invention provides a method for judging touch events in a touch detection system. A relatively simple digital preliminary judgment can replace the existing complete judgment to judge whether a touch event occurs. In order to improve the noise detection capability, non-uniform sampling can be used to eliminate or reduce regular noise, and a noise detection method realized by the summation of sensing signals with different polarity patterns can be used to eliminate or reduce irregular noise. Although the complete judgment has a higher resolution, its circuit is more complicated and requires more time and power consumption, so it is only used when the digital preliminary judgment judges that a touch event has occurred or that the sensing signal is judged to be disturbed by noise. In this way, the present invention can achieve the effect of reducing time consumption and power consumption.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (13)

1. A method of determining a touch event, comprising:

receiving a sensing signal;

performing a digital preliminary judgment on the sensing signal to judge whether a touch event occurs;

judging whether the sensing signal is interfered by a noise signal or not, wherein the noise signal comprises irregular noise;

when the touch event is judged to occur or the sensing signal is judged to be interfered by the noise signal, a complete judgment is carried out on the sensing signal; and

and when the touch event is not judged to occur and the sensing signal is not judged to be interfered by the noise signal, not performing the complete judgment on the sensing signal.

2. The method of claim 1, wherein the full judgment comprises a series of digitized judgments.

3. The method of claim 1, wherein the complete determination comprises a maximum likelihood operation or a signal processing mechanism using filters.

4. The method of claim 1, wherein the step of performing the digital initial decision on the sense signal comprises:

a non-uniform sampling of the sense signal is performed.

5. The method of claim 4, wherein the step of performing the non-uniform sampling of the sense signal comprises:

deleting at least one segment of the sensing signal before sampling the sensing signal, wherein the at least one segment is disturbed by a regular noise.

6. The method of claim 5, wherein the non-uniform sampling operates as described by the following general equation:

wherein, r (t) represents the sensing signal, which is divided into a signal component a × g (t) and a noise component noise (t), g (t) represents a basic signal, and sequence (t) represents a time sequence of the sensing signal remaining after deleting the at least one segment.

7. The method of claim 1, further comprising:

reserving a plurality of digitization judgment times for the digitization initial judgment and a plurality of complete judgment times for the complete judgment in an alternating manner, wherein each digitization judgment time of the digitization initial judgment times is immediately before one complete judgment time of the complete judgment times.

8. The method of claim 1, wherein the full decision provides a higher resolution than the digitized preliminary decision.

9. The method of claim 1, wherein the full determination provides more touch information than the digitized preliminary determination.

10. The method of claim 9, wherein the more touch information comprises touch intensity, signal magnitude, or touch location.

11. The method of claim 1, further comprising:

judging whether a plurality of judgment results of the sensing signal are interfered by the noise signal; and

and selecting at least one judgment result which is judged not to be interfered by the noise signal in the plurality of judgment results to judge touch information related to the touch event.

12. A method of determining a touch event, comprising:

receiving a sensing signal;

executing a first judgment on the sensing signal to judge whether a touch event occurs;

judging whether the sensing signal is interfered by a noise signal or not, wherein the noise signal comprises irregular noise;

performing a second determination on the sensing signal after determining that the touch event occurs or determining that the sensing signal is interfered by the noise signal; and

and after the touch event is judged not to occur and the sensing signal is judged not to be interfered by the noise signal, not performing the second judgment on the sensing signal, wherein the second judgment provides higher resolution or more touch information than the first judgment.

13. The method of claim 12, wherein the more touch information comprises touch intensity, signal magnitude, or touch location.

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