CN110058722B

CN110058722B - Method for judging touch event in touch detection system

Info

Publication number: CN110058722B
Application number: CN201910012580.9A
Authority: CN
Inventors: 郭弘政; 陈俊宏; 黄俊憬
Original assignee: Novatek Microelectronics Corp
Current assignee: Novatek Microelectronics Corp
Priority date: 2014-05-22
Filing date: 2015-05-22
Publication date: 2022-06-07
Anticipated expiration: 2035-05-22
Also published as: CN105094420B; CN105094420A; CN110058722A

Abstract

The invention discloses a method for judging a touch event in a touch detection system, which comprises the steps of 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; 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; and when the touch event is judged to occur or the sensing signal is judged to be interfered by the noise signal, carrying out complete judgment on the sensing signal. By the method, the effects of reducing time consumption and power consumption can be achieved.

Description

Method for judging touch event in touch detection system

The application date of the original application is 22/5/2015, the application number of the original application is 201510267094.3, and the title of the original application is "method for determining touch events in a touch detection system".

Technical Field

The present invention relates to a method for determining a touch event in a touch sensing system, and more particularly, to a method for determining a touch event in a touch sensing system by digital initial determination.

Background

In recent years, touch sensing technology has been rapidly developed, and many consumer electronics products, such as mobile phones (mobile phones), satellite navigation systems (GPS navigator systems), tablet computers (tablets), Personal Digital Assistants (PDAs), and laptop computers (laptops), have a touch function built therein. In the above electronic products, the area of the original display panel is provided with a touch sensing function, that is, the original display panel is converted into a touch display panel with a touch recognition function. Generally, the touch screen can be classified into an out-cell (out-cell) touch screen and an in-cell/on-cell (in-cell/on-cell) touch screen according to different structural designs of the touch screen. The external touch screen is formed by combining an independent touch screen and a common display panel, and the embedded touch screen is formed by directly arranging a touch sensing device on the inner side or the outer side of a substrate in the display panel.

The sensing technology of touch can be classified into resistive, capacitive and optical. The capacitive touch screen has become the mainstream of the market gradually because of its advantages of high sensing accuracy, high transmittance, fast response speed, long service life, and the like. In a conventional capacitive touch detection system, a touch screen or a screen is provided with a plurality of capacitors for touch detection. In the conventional touch detection, complete judgment is often required to be performed to judge whether a touch event occurs, a position where the touch occurs and touch intensity. For example, when a touch event occurs, the touch control module may perform interpolation operation on sensing signals from different capacitors on the touch screen to determine the position where the touch occurs. By the method, the numerical value of each sensing signal can be obtained to judge the touch strength received by each position on the touch screen, and accurate touch judgment is further achieved. This takes a long time and generates a large power consumption in the touch detection system.

In addition, noise (e.g., liquid crystal module noise (LCM noise)) often exists in the sensing signal, and the noise reduces the reporting rate of touch events. To obtain a better report rate, the conventional noise detection and error correction method usually employs a strong filter to filter the noise. However, powerful filters typically have a narrow bandwidth to control the passage of a particular signal, but a narrow bandwidth may correspond to a longer time consumption in the time domain. In addition, the touch control module can also perform complex analog operation on the sensing signal to eliminate or reduce interference caused by noise.

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

Disclosure of Invention

Therefore, the present invention is directed to a method for determining a touch event in a touch detection system by digital initial determination, so as to achieve the advantages of reducing time and power consumption in the touch detection system.

The invention discloses a method for judging a touch event in a touch detection system. The method for judging the touch event comprises the steps of 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; 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; and when the touch event is judged to occur or the sensing signal is judged to be interfered by the noise signal, carrying out complete judgment on the sensing signal.

Drawings

Fig. 1 is a schematic waveform diagram illustrating a touch event determined by a sensing signal.

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

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

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

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

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

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

Fig. 8 is a schematic diagram illustrating an operation manner of the touch control module performing the preliminary digital judgment and the complete digital judgment according to the embodiment of the present invention.

Fig. 9 is a schematic diagram illustrating another operation manner of the touch control module according to the embodiment of the present invention to perform the preliminary digital judgment and the complete digital judgment.

Fig. 10 is a schematic diagram illustrating an operation manner in which the touch control module performs a series of digital determination and a summation signal recombination according to an embodiment of the invention.

Wherein the reference numerals are as follows:

TH critical value

20. 600 touch screen

30 touch detection process

300 to 312 steps

Curves L1, L2

702. 704, 706 areas

TX _ 1-TX _ M driving line

RX _1 RX _ N sense line

Y1-Ym drive signal

X1-Xn sensing signal

TS 1-TSn subinterval

Capacitance value generated by C11-CMn touch gesture

N11-NMn noise signal

RX Sum _1 to RX Sum _ n, A1 to A4, and Sum signal

B1～B4、C1～C4、D1～D4

TX Sum _1 to TX Sum _ M, NF, SA, SB, SC, the Sum

SD、SA’、SB’、SC’、SD’

Detailed Description

As mentioned above, the conventional complete determination method is time consuming and power consuming, and therefore a better method for determining a touch event in a touch detection system is required. Generally, a touch control module of a touch detection system may transmit a driving signal to a capacitor on a touch screen and receive a sensing signal from the capacitor to determine whether a touch event occurs, and may preset a threshold value for determining the touch event with respect to the sensing signal.

Referring to fig. 1, fig. 1 is a schematic waveform diagram illustrating a touch event determined by a sensing signal. Fig. 1 includes a threshold TH and a sensing signal. If the sensing signal is lower than the threshold value TH, the touch event can be judged to occur; on the contrary, if the sensing signal is higher than the threshold TH, it indicates that no touch occurs on the touch screen.

As shown in fig. 1, the sensing signal requires high resolution if the sensing signal indicates that a touch event occurs. 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 touch intensity of a touch event. In this case, a complete determination is required to calculate the touch information. On the other hand, if the sensing signal indicates that the touch event does not occur, the above-mentioned complete determination is not needed. Further, in the case of determining a touch event by the threshold value TH without further determination, the sensing signal only needs a low resolution. That is, since the above determination only includes two determination results, which can be represented by one bit, a simple operation is sufficient to handle the low resolution determination method. In this case, the full determination with the higher resolution required needs to be performed only when a touch event occurs.

Referring to fig. 2, fig. 2 is a schematic diagram illustrating a touch event 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 detected at only a single or a few locations, or even not detected at all, across the entire touch screen. A high resolution full determination is not required for most locations where no touch event occurs.

From this, in terms of time, a touch event occurs only part of the time during a period; in terms of space, a touch event occurs only at a partial location among the entire touch screen. Therefore, in most of time and most of space, the low resolution digital initial judgment is enough to process the sensing signal without the need of high resolution complete judgment.

The digital preliminary judgment can use a simple circuit structure, and can reduce power consumption and required time consumption. However, the simplified digital initialization results in a reduction in noise detection capability. Fortunately, U.S. patent applications 14/607,031 and 14/285,604 provide a method for noise detection that is efficient without using large filters, which include complex circuitry and consume a large amount of time. In addition, part of the regular noise can be eliminated or reduced by non-uniform sampling (non-uniform sampling). These methods of detection and noise reduction allow simple digital initialization to be implemented in touch detection systems.

Referring to fig. 3, fig. 3 is a schematic diagram of a touch detection process 30 according to an embodiment of the 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 systems. The touch detection process 30 includes the following steps:

step 300: and starting.

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

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

Step 306: and performing a digital initial 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: and judging whether the sensing signal is interfered by a noise signal. If yes, go to step 310; if not, go to step 312.

Step 310: a complete determination is performed on the sensing signal.

Step 312: and (6) ending.

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. Then, the touch control module performs a digital preliminary judgment on the sensing signal to judge whether a touch event occurs. The initial digital determination can be performed by simply comparing the sensing signal with a threshold (e.g., threshold TH shown in fig. 1) without additionally determining other touch information, such as touch intensity, signal magnitude, and touch position. Therefore, in the step of performing the initial digital judgment, the touch control module knows whether a touch event occurs, but cannot obtain complete information related to the touch event, such as the position where the touch event occurs.

If the comparison result of the digital preliminary judgment indicates that a touch event occurs, the touch control module performs a complete judgment on the sensing signal to obtain complete touch information, and then judges the touch position and/or the touch intensity, that is, in the step of performing the complete judgment, a more time-consuming high-resolution operation needs to be performed. On the other hand, if the comparison result of the initial digital judgment indicates that no touch event occurs, the touch control module additionally judges whether the sensing signal is interfered by a noise signal. If the noise interfering the sensing signal is detected, the touch control module also starts complete judgment for the sensing signal to eliminate or reduce noise interference, and then judges the touch position and/or touch strength (if the touch occurs). If no noise is detected, the touch control module does not perform complete judgment on the sensing signal, and in this case, time and power consumption can be saved.

Therefore, the complete judgment with higher resolution and more time consumption is only performed when the touch event is determined to occur or the sensing signal is determined to be interfered by the noise signal. In other words, if it is determined that no touch event occurs and the sensing signal is not interfered by the noise signal, the sensing signal can be ignored without performing a complete determination.

In addition, as described above, a complete determination is not required most of the time and most of the space for a touch screen. Therefore, compared with the prior touch control module which executes complete judgment on all received sensing signals, the invention only uses complete judgment when the digital initial judgment indicates the occurrence of a touch event or the noise detection method indicates the existence of noise. In one embodiment, the complete determination may include a signal processing mechanism using a large filter to filter out or eliminate any possible noise. In another embodiment, the complete determination may include a maximum likelihood (maximum likelihood) operation method for estimating the magnitude of the touch intensity corresponding to each sensing signal, so that the touch control module can accurately calculate the touch position and/or the touch intensity. Compared to digital initial decisions, complete decisions (e.g., large filters or maximum likelihood operations) provide higher resolution touch decisions that require significantly more computation time than digital initial decisions. Therefore, in the touch detection process 30, the advantage of reducing time consumption and power consumption can be achieved by reducing the number of times of using the complete judgment.

It should be noted 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 determination can still be performed.

Generally, the noise signal of the touch detection system can be divided into two types: regular noise and irregular noise. To avoid false touch hits, both regular and irregular noise must be eliminated or reduced. Irregular noise can be processed by the noise detection methods described in U.S. patent applications 14/607,031 and 14/285,604, while regular noise can be eliminated by non-uniform sampling in the digital synthesis. The regular noise may be any type of noise generated by regular operation of an electronic system associated with the touch detection system, such as liquid crystal module noise (LCM noise) or other artifacts in a Liquid Crystal Display (LCD) system. For example, regular noise can be generated by a circuit device in the lcd system, and when the circuit device generates a noise signal, the circuit device sends related information about the time when the noise signal reaches the sensing lines on the touch screen, so that the touch detection system knows where the regular noise will interfere with the sensing signals.

Referring to fig. 4A and 4B, fig. 4A and 4B are schematic diagrams illustrating non-uniform sampling of a sensing signal interfered 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, the sensing signal is severely interfered by the noise signal, and the range of the noise signal can reach-1 to 1. As can be seen from fig. 4A, the noise signal on the sensing signal obviously affects the determination result of the touch event. According to the non-uniform sampling, at least one segment of the sensing signal may be deleted before sampling the sensing signal, wherein the deleted segment is a portion interfered by regular noise. In other words, since the touch detection system knows where the noise interference occurs, the noise-interfered portion of the sensing signal can be eliminated by non-uniform sampling, as shown in fig. 4B. Therefore, the touch detection system only samples the part of the sensing signal which is not interfered by the noise.

It should be noted that the existing signal processing mechanism for making a complete judgment usually performs signal processing in the frequency domain, which often needs to use a powerful filter to eliminate noise signals, in which case, when the used filter is stronger, it takes more time to perform signal processing. On the other hand, different from the existing complete judgment method, the digital initial judgment of the invention adopts non-uniform sampling to eliminate the interference of regular noise in the time domain, the implementation mode is simpler, and the noise problem can be solved under the condition of spending less time and using a circuit with lower complexity. For example, in one embodiment, non-uniform sampling can be achieved by a multiplexer having two inputs, one output, and a control controlled by a control signal, wherein one input receives the sensing signal and the other input receives zero. During the period (such as time point A) that the sensing signal is interfered by regular noise, the control signal can control the multiplexer to output zero potential; the control signal controls the multiplexer to output the sensing signal during a period (e.g., time point B) when the sensing signal is not interfered by the regular noise. In other embodiments, non-uniform sampling may also be achieved in other ways, without limitation.

Referring to fig. 5, fig. 5 is a line graph showing normalized error (normalized error) of the sampling result of the sensing signal interfered by noise, in which a value 1 represents an accurate sampling result, and values 1.1, 1.2, 1.3 and 1.4 represent errors of the sampling result of the sensing signal, respectively, of 10%, 20%, 30% and 40%. The curve L1 corresponds to the sensing signal before non-uniform sampling, and the curve L2 corresponds to the sensing signal after non-uniform sampling. As shown in fig. 5, due to noise interference, there is an error of about 30% to 40% in the sampling result, and after non-uniform sampling is performed, the error can be greatly reduced to 0% to 5%. Therefore, the non-uniform sampling has a strong error reduction effect. In addition, since the error is reduced to about one eighth of the original error, the sensing signal can be amplified eight times before entering an analog-to-digital converter (ADC) of the touch control module, so that the dynamic range of the ADC is improved by 3 bits, thereby greatly improving the efficiency of the ADC.

The operation of non-uniform sampling can be described by the following general equation:

wherein, 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, and sequence (t) represents a time sequence of the sensing signal remaining after deleting at least one segment, which is a noise-disturbed part of the sensing signal. As shown in the general equation, the sensing signal can be divided into a signal component and a noise component, and therefore, by selecting an appropriate sequence (t), the noise component can be effectively eliminated.

In addition, noise (e.g., irregular noise) that cannot be eliminated by non-uniform sampling can be detected by the noise detection methods described in U.S. patent applications 14/607,031 and 14/285,604. Referring to fig. 6 and 7, fig. 6 is a schematic diagram of a touch screen 600 according to an embodiment of the invention, and fig. 7 is a schematic diagram illustrating data distribution of the touch screen 600 when the touch screen is driven. As shown in FIG. 6, the touch screen 600 includes a plurality of driving lines TX _1 TX _ M and a plurality of sensing lines RX _1 RX _ N for sensing a touch gesture on the touch screen 600, wherein M, N is a positive integer 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 to drive the sensing lines RX _ 1-RX _ N to generate a plurality of sensing signals X1-Xn during a time period (time period) with a specific time length, wherein M and N are positive integers greater than 1.

Referring to fig. 7, the horizontal axis represents a time interval, the timing of which increases from left to right, and the vertical axis represents the driving direction of the touch screen 600, which is sequentially scanned from the driving line TX _1 to the driving line TX _ M from top to bottom. In the present exemplary embodiment, the time interval includes a plurality of sub-intervals (time slots) TS 1-TSn. In the area 706, data Cji + Nji marked at the intersection of the driving lines TX _1 TX _ M and the sensing lines RX _1 RX _ N represents 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 external environment, wherein j is a positive integer from 1 to M, i is a positive integer from 1 to N, and M, N is a positive integer greater than 1. The noise signal Nji may include various types of noise, such as irregular noise, that cannot be eliminated by non-uniform sampling. 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 the Sum obtained by a touch control module respectively calculating the signal values of the sensing signals X1 Xn during the time interval. That is, the Sum signal RX Sum _ I represents the Sum of data obtained by the sensing line RX _ I from each of the driving lines TX _1 to TX _ M in the sub-interval TSi of the time interval, wherein 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 the time interval. The Sum signals RX Sum _1 to RX Sum _ n can be expressed by the following formulas:

wherein RX Sum _ i represents a Sum signal, Cji represents a capacitance value generated by a touch gesture, Nji represents noise generated by the touch screen 600 being affected by the outside, where j is a positive integer from 1 to M, i is a positive integer from 1 to n, and M, n is a positive integer greater than 1.

In the present exemplary embodiment, each of the driving signals Y1-Ym has a first polarity pattern and a second polarity pattern. In this time interval, the calculation results of the first polarity pattern and the second polarity pattern of the driving signals Y1 to Ym are substantially zero. In this example, the first and second polarity patterns of the driving signals Y1 Ym and Y Ym are summed, that is, the Sum TX Sum _1 TX Sum _ M of the driving signals Y1 Ym marked at the positions corresponding to the driving lines TX _1 TX _ M in fig. 6 in the region 702 is zero, which means that the Sum of the first and second polarity patterns of the driving signals Y1 Ym is substantially zero in this time interval.

For example, take 4 driving signals Y1-Y4 as an example. In the exemplary embodiment, the polarity distribution of each of the driving signals Y1 to Y4 in the time interval including 2 sub-intervals TS1 and TS2 is as 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 to Y4 have the first polarity pattern in the corresponding sub-section, and "1" indicates that the driving signals Y1 to Y4 have the second polarity pattern in the corresponding sub-section. Therefore, in the column of the driving line TX _1, when 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 of the driving signals Y2Y 4 for driving the lines TX _2 TX _4 can be analogized. In addition, the polarity distribution patterns of the driving signals Y1-Y4 are not limited to those shown in table 1, and other examples are shown in U.S. patent applications 14/607,031 and 14/285,604, which are not repeated herein.

Referring to fig. 6 and 7 again, and in combination with the driving concept disclosed in the embodiment of table 1, the touch control module of the touch screen 600 can respectively calculate the Sum of the signal values of the sensing signals X1-Xn in a time interval of a specific time length to obtain the Sum signals RX Sum _ 1-RX Sum _ n. Then, the touch control module recalculates the Sum signals RX Sum _1 RX Sum _ n to obtain the Sum NF of the Sum signals RX Sum _1 RX Sum _ n, i.e. the Sum NF

The Sum NF obtained by the touch control module calculating the Sum signals RX Sum _1 to RX Sum _ n represents the noise generated by the touch screen 600 due to the external influence. Therefore, by using the noise detection method, the noise signal generated by the external influence can be quickly and accurately estimated.

It can be seen 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 a touch event exists on the touch screen 600. Therefore, if the sum NF is any non-zero value, it is considered as being interfered by noise, and the noise signal can be detected in the above manner. For example, the step 308 of the touch detection process 30 can be implemented by the touch detection method described above, which obtains the sum NF to determine whether the sensing signal includes noise. If the sum NF is equal to zero, the sensing signal can be judged to have no noise; if the sum NF is not equal to zero, the sensing signal can be judged to be interfered by the noise signal, and then the noise signal is processed by using complete judgment. In another embodiment, the touch control module may further preset a threshold for the sum NF, and if the sum NF exceeds the threshold, it may be determined that the sensing signal is interfered by the noise signal.

Referring to fig. 8, fig. 8 is a schematic diagram illustrating 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 schedule a time course to reserve a plurality of digitization judgment times for digitization initial judgment and a plurality of full judgment times for full judgment in an alternating manner within a period, wherein each of the plurality of digitization judgment times is immediately before one of the plurality of full judgment times. Within each digital judgment time, the digital initial judgment and noise detection method can be executed once. If the digitized preliminary judgment or noise detection method indicates that a complete judgment is required due to occurrence of a touch event or noise interference, the touch control module performs the complete judgment within the next complete judgment time (as shown in the first complete judgment time in fig. 8). If the digital preliminary judgment and the noise detection method respectively indicate that the touch event and the noise interference do not occur, and therefore the complete judgment is not needed, the touch control module does not execute the complete judgment within the next complete judgment time, and the touch control module waits for the next digital judgment time and then starts to execute the digital preliminary judgment (as shown in the second complete judgment time in fig. 8). By the method, complete judgment can be performed in a small amount of time or partial time, so that power consumption can be reduced. However, this scheduling method is simple and cannot reduce the time consumption. In other embodiments, the next digital preliminary judgment can be directly performed when the complete judgment is not needed, so as to reduce the time consumption.

It should be noted that, in addition to the signal processing method using the large filter and the maximum likelihood operation, the complete determination can be realized by a series of digital determinations to achieve high resolution. More specifically, although only low-resolution touch detection can be obtained by one-time digitization determination, high-resolution touch detection can be achieved by performing a series of digitization determinations.

For example, referring to fig. 9, fig. 9 is a schematic view illustrating another operation manner of the touch control module according to the embodiment of the present invention to perform the preliminary digital judgment and the complete digital judgment. 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 case, the touch control module may perform the digital determination one or two times to determine whether a touch event occurs and determine whether the sensing signal is interfered by noise. Other digital determinations are performed as necessary, i.e., upon detection of a touch event or noise signal. For example, in FIG. 9, a full judgment time comprises four digital judgment times, wherein each digital judgment time can perform one digital judgment. The touch control module can firstly execute digital judgment within the first and second digital judgment time, and judge whether to execute more digital judgment according to the judgment result obtained within the first and second digital judgment time. The determination result obtained from each digital determination indicates whether a touch event occurs and whether a noise signal exists, and the noise signal can be determined according to the sum signal obtained from the sensing signal by the noise detection method. If a touch event or a noise signal is detected, the touch control module may further perform a digital determination within the third and fourth digital determination periods to obtain touch position information with a higher resolution and/or eliminate interference of noise. On the other hand, if no touch event or noise signal is detected, the third and fourth digitization decision periods are not executed.

With continued reference to fig. 9, fig. 9 illustrates how a series of digital determination operations may be combined with the noise detection method. In the third complete determination time shown in fig. 9, the touch control module may first perform the digital determination within the first and second digital determination times, and determine that the determination result of the second digital determination is interfered by noise. In this case, the touch control module further performs the digital judgment in the third and fourth digital judgment time. Then, the touch control module obtains four judgment results corresponding to the sensing signals of the four times of digital judgment, and judges whether the judgment results are interfered by noise signals. The touch control module can selectively adopt at least one judgment result which is judged not to be interfered by the noise in the judgment results to judge the touch information related to the touch event, such as the touch position and the like. As shown in the third complete determination time of fig. 9, the determination results obtained by the second and third digital determinations are interfered by noise, and the touch control module thus selects to determine the occurrence and/or touch position of the touch event by using the determination results obtained by the first and fourth digital determinations.

It is noted that according to the noise detection method described in U.S. patent application 14/607,031, the sum signals obtained in different time intervals can be recombined to obtain another sum NF 'with a smaller value than the original sum NF, i.e., the sum signal corresponding to the sum NF' is less noisy than the sum signal corresponding to the sum NF. Please refer to fig. 6 and fig. 7 again. The touch control module may obtain first sum signals A, B, C and D respectively corresponding to the sensing lines RX _1 to RX _4 in a first time interval, and a sum NF3 of signal values of the first sum signals A, B, C and D (NF3 is a + B + C + D) represents a noise signal value calculated by the touch control module after the first noise detection method is performed. Then, the touch control module obtains second sum signals a ', B', C 'and D' respectively corresponding to the sensing lines RX _1 to RX _4 in a second time interval, and a sum NF4(NF4 ═ a '+ B' + C '+ D') of signal values of the second sum signals a ', B', C 'and D' represents a noise signal value calculated by the touch control module after executing the second noise detection method.

In the present exemplary embodiment, the touch control module may replace part or all of the first sum signals A, B, C and D with at least one of the second sum signals a ', B', C ', and D' such that the sum NF5 of the signal values thereof after being recombined by the second sum signals a ', B', C ', and D' and the first sum signals A, B, C and D is smaller than the sum NF3 of the signal values of the first sum signals before being recombined. In the above manner, after any possible recombination is performed on the sum signals, the best sum signal combination, i.e. the combination that is least disturbed by noise, can be determined by finding the smallest sum. Compared with the mode of removing the judgment result with the sum not equal to zero, the recombination and selection mode can judge the touch event and the touch position more accurately. It should be noted that in the embodiment shown in fig. 9, although the sum of the summation signals is interfered by noise, the portion or the majority of the summation signals included in the sum are still accurate. Therefore, the accurate sum signals can be combined with other accurate sum signals obtained in other time intervals through a recombination mode, and in this case, more effective data in the sum signals can be saved so as to obtain more accurate touch judgment.

Referring to fig. 10, fig. 10 is a schematic diagram illustrating an operation manner in which the touch control module performs a series of digital determinations and a summation signal is recombined according to an embodiment of the present invention. As shown in FIG. 10, each large square represents a digitized determination time, which can be regarded as a time interval for generating a determination result, wherein the determination result can be indicated by a sum of four sum signals (e.g., sum signals A1-A4, B1-B4, C1-C4, or D1-D4). After the touch control module performs the digitizing determinations within four digitizing determination periods, the sum SA, SB, SC, and SD corresponding to each digitizing determination can be obtained, where SA is equal to the sum of the sum signals A1, A2, A3, and A4, SB is equal to the sum of the sum signals B1, B2, B3, and B4, SC is equal to the sum of the sum signals C1, C2, C3, and C4, and SD is equal to the sum of the sum signals D1, D2, D3, and D4. Then, the touch control module performs recombination, for example, as shown in fig. 10, the sum signals a1, B1, C1 and D1 may be combined with each other to obtain a sum SA ', the sum signals a2, B2, C2 and D2 may be combined with each other to obtain a sum SB', the sum signals A3, B3, C3 and D3 may be combined with each other to obtain a sum SC ', and the sum signals a4, B4, C4 and D4 may be combined with each other to obtain a sum SD'. More specifically, the touch control module can combine any number of the sum signals A1-A4, B1-B4, C1-C4, and D1-D4 to obtain the sum. In one embodiment, the touch control module can find the minimum sum to obtain four or any number of sum signals that are most susceptible to noise interference, and selectively use the sum signals to determine touch information, such as occurrence of a touch event and/or touch location. On the other hand, the touch control module can find out the sum smaller than a critical value and obtain the sum signal included in the sum, and then the touch control module judges the touch information according to the sum signals. As shown in fig. 10, after several times of recombination, the touch control module may determine that the sum signals a2, A3, a4, B2, C1, C4, D1, D2, and D3 are not interfered by noise, and select to use the sum signals to determine the touch information. In this case, optimized touch information can be obtained by selecting to use all the sum signals that are not interfered by noise and to exclude all the sum signals that are interfered by noise.

In summary, the present invention provides a method for determining a touch event in a touch detection system. The simpler digital initial judgment can replace the existing complete judgment to judge whether the touch event occurs. To improve the noise detection capability, non-uniform sampling can be used to eliminate or reduce regular noise, and the noise detection method implemented by the sum of the sensing signals with different polarity patterns can be used to eliminate or reduce irregular noise. Although the complete determination has a higher resolution, the circuit is more complex and requires more time and power consumption, so the complete determination is only used when the occurrence of the touch event is determined by the digital initial determination or the sensing signal is determined to be interfered by noise. Therefore, the invention can achieve the effects of reducing time consumption and power consumption.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

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;

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.