CN101526865B - How the touchpad detects multiple touches - Google Patents

Abstract

A method for detecting multiple finger touches on a touch panel, the touch panel includes a plurality of scan lines, the method includes the following steps: sequentially scanning the scan lines, and checking whether each scan line generates a plurality of sensing values greater than a threshold value, if so, then checking whether the scan lines with sensing values greater than the threshold value are adjacent, if still, finding at least one corresponding scan line group, and according to the number of the group, determining that the scan lines have finger touches corresponding to the number of the group. Therefore, the method proposed by the present invention can effectively determine the number and position of multiple fingers, and prevent noise from interfering with the scanning detection of the touch panel, resulting in misjudgment, so as to achieve the purpose of correctly determining whether each finger touch is actually located on the touch panel.

Description

How the touchpad detects multiple touches

technical field

The present invention relates to a method for detecting touch motions on a touch panel, in particular to a method for detecting multi-finger touches on a touch panel.

Background technique

According to the current development trend of increasingly complex multimedia systems, there are more and more functions, and the corresponding operation interface is becoming more and more complex. However, more functions mean that more related operation buttons need to be set on the device, but Under the requirement of each system to be smaller and more delicate, these buttons cannot be added to the system completely; therefore, relevant developers use touch panel technology to save the space required for most of the operation buttons.

In short, a touchpad is an input that allows users to use fingers or other objects (such as a stylus) to directly touch and slide on its panel or use gestures instead of buttons to control the movement of the cursor on the display. device, coupled with the advantage of the touchpad being thin and light, it is often combined with a notebook computer, a personal digital assistant (PDA), a digital player, or other electronic devices that only have limited installation space.

However, devices that detect single-finger gesture commands such as touch, move, and leave by using a traditional touchpad are not enough for the application of current electronic products; therefore, related companies have also developed in recent years For the technical method of how to discriminate multi-finger touch commands on the touch panel, such as the "Multiple finger contact sensing method for emulating mouse button on a touch panel and the multi-finger touch sensing method for emulating mouse button operation" in US Patent No. 5825352 buttons and mouseoperations on a touch sensor pad) discloses a method of detecting the touch of a finger by detecting the waveform of the sensing value of the touch panel. As shown in Figure 1, the method is to preset a maximum threshold value 10 and a minimum threshold value 20, and then detect the capacitance or resistance change generated by the scanning line of the touch panel 1, and judge the formed Whether the peak of the induction waveform 101 is not less than the aforementioned maximum threshold value of 10, if one of the scanning lines has only one induction waveform 101 and is not less than the maximum threshold value of 10, it is judged as a finger touch; For the two sensing waveforms 101 and 102, it is necessary to first judge whether the peaks of the two waveforms 101 and 102 are not less than the aforementioned maximum threshold value 10. If only one sensing waveform matches, it is still judged as a finger touch. When the peaks of the waveforms 101 and 102 are not less than the maximum threshold value of 10, continue to check whether the trough formed between the two waveforms 101 and 102 is not greater than the aforementioned minimum threshold value of 20. If so, it is judged as two independent finger touches. .

However, as shown in FIG. 2 , the touch panel 1 disclosed above is prone to misjudgment because the touch panel 1 is disturbed by noise, especially when the signal waveform 100 of the noise is also greater than When the maximum threshold value used to determine whether it is a finger touch is 10, it will be misjudged as a finger touch. The misjudgment is the touch pressure of two fingers; therefore, how to improve the detection method of the touch panel 1 to effectively prevent the misjudgment caused by noise interference has become the research direction that relevant industry companies want to study hard.

Contents of the invention

The object of the present invention is to provide a one-dimensional detection method that can avoid noise interference and can recognize multi-finger touches on the touch panel.

Another object of the present invention can be achieved through the following technologies. The method for detecting multi-finger touches on a touch panel includes the following steps:

(a), scanning the plurality of scan lines;

(b), check whether each of the plurality of scanning lines produces a plurality of sensing values greater than a threshold value, if so, proceed to the next step;

(c), check whether there are at least two adjacent scan lines whose sensing values are greater than the threshold value, and if so, find out the corresponding at least one group of two adjacent scanning lines whose sensing values are greater than the threshold value Scanning lines to form scanning line groups, and according to the number of groups, it is determined that the plurality of scanning lines have reference finger touches corresponding to the number of groups;

(d), check whether the number of scanning lines of the induction value generated in the reference finger touch is not greater than a reference value, if so, each reference finger touch is a real finger touch, if not, each reference finger touch Includes multiple real finger touches;

(e) Calculate the positions of the centers of gravity according to the determined sensing values of the real finger touches, and mark each position of the center of gravity as a finger touch source.

The method for detecting multi-finger touch on the touch panel is characterized in that in the method (c), if the plurality of scanning lines that generate the sensing values are not adjacent to each other, then it is determined that The sensing values generated by the plurality of scan lines are noise.

The method for detecting multi-finger touches on the touch panel is characterized in that in the step (b), if the multiple scanning lines do not detect a sensing value greater than the threshold value, then Repeat step (a).

The method for detecting multi-finger touches on a touch panel is characterized in that in the step (a) of the method, the method of scanning the plurality of scanning lines can be row-by-row or cross-skip scanning.

A method for detecting multi-finger touches on a touch panel, the touch panel comprising a plurality of first scanning lines and a plurality of second scanning lines intersecting with the plurality of first scanning lines, the method comprising the following steps:

(a), scanning the plurality of first scanning lines and second scanning lines;

(b), check whether the plurality of first scanning lines produce a plurality of sensing values greater than a threshold value, if so, proceed to the next step;

(c) Check whether at least two of the plurality of first scan lines whose sensing values are greater than the threshold value are adjacent, if so, find the corresponding first group of at least one scan line, and proceed to the next step;

(d), check whether the plurality of second scanning lines generate a plurality of sensing values greater than a threshold value, if so, proceed to the next step;

(e), check whether the plurality of second scan lines whose sensing values are greater than the threshold value are adjacent, and if so, find out the corresponding second group of at least one scan line; and

(f), comparing whether the numbers of the first group and the second group are equal; Reference finger touch, if not, use the smaller number of groups as the determined reference finger touch;

(g), check whether the number of the first scanning line and the second scanning line of the induction value generated in the reference finger touch is not greater than a reference value, if so, then each reference finger touch is a real finger touch, if not , then each reference finger touch includes multiple real finger touches;

(h) Calculate the positions of the centers of gravity according to the determined sensing values in the real finger touches, and mark each position of the center of gravity as a finger touch source.

The method for detecting multi-finger touches on a touch panel is characterized in that in step (c), if the plurality of first scanning lines that generate sensing values are not adjacent to each other, then it is determined that the multi-finger touch The sensing value generated by the first scan line is noise.

The method for detecting multi-finger touches on a touch panel is characterized in that in step (e), if the plurality of second scanning lines that generate sensing values are not adjacent to each other, then it is determined that the multi-finger touch The sensing value generated by the first scanning line and the second scanning line is noise.

The method for detecting multi-finger touches on the touch panel is characterized in that in the step (b), if the plurality of first scanning lines do not detect a sensing value greater than the threshold value, repeat Step (a).

The method for detecting multi-finger touches on the touch panel is characterized in that in the step (d), if no sensing value greater than the threshold value is detected in the plurality of second scanning lines, then it is determined that The sensing values generated by the plurality of first scanning lines are noise, and step (a) is repeated.

The method for detecting multi-finger touches on the touch panel is characterized in that in the step (a), the scanning of the plurality of first scanning lines and the second scanning lines can be performed by row-by-row or cross-skip scanning .

The effect of the present invention is to find the group of each finger by setting the threshold value and comparing it with the sensing value generated by individual finger touches on each scanning line of the touch panel to perform finger touch The detection and judgment of each finger can effectively reduce the misjudgment caused by noise interference, so as to correctly judge the state of each finger touching the touch panel.

Description of drawings

FIG. 1 is a schematic diagram illustrating the state of a conventional touch panel sensing finger touch;

FIG. 2 is a schematic diagram illustrating a state in which the conventional touch panel is disturbed by a noise;

FIG. 3 is a schematic diagram illustrating the implementation of the first preferred embodiment of the method for detecting multi-finger touches on a touch panel of the present invention;

Fig. 4 is a schematic diagram illustrating the state of the first preferred embodiment during detection;

Fig. 5 is a schematic diagram illustrating the state of detecting two and relying on fingers in the first preferred embodiment;

Fig. 6 is a flow chart illustrating the detection step process of the first preferred embodiment;

7 is a schematic diagram illustrating the implementation of the second preferred embodiment of the method for detecting multi-finger touches on a touch panel of the present invention;

Fig. 8 is a schematic diagram illustrating the state of the second preferred embodiment during detection;

Fig. 9 is a flowchart illustrating the first half of the detection step of the second preferred embodiment;

FIG. 10 is a flow chart, continuing to illustrate the second half of the process of the detection step of the second teacher embodiment.

Explanation of main component symbols in the drawings:

21~27 steps, 301~313 steps, 4 touch panels, 40 scan lines, 400 noise, 401 second scan lines, 402 first scan lines, 41~44 scan lines, 45 groups, 46 reference finger touch, 47 Real finger touch, 48 center of gravity position, 49 first group, 50 second group, 60 threshold value, 61 sensing value, 71 fingers.

Implementation

The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the second preferred embodiment with reference to the drawings.

Before the present invention is described in detail, it should be noted that in the following description, similar components are denoted by the same numerals.

Referring to Fig. 3, Fig. 4 and Fig. 5, it is the first preferred embodiment of the method for detecting multi-finger touch on the touch panel of the present invention. The touch panel 4 can be capacitive, resistive or utilize electricity, light waves, An inductive touch panel 4 such as a sound wave, and includes a plurality of scanning lines 40, and the method includes the following steps:

First, as shown in step 21 , the iso-scanning lines 40 are scanned.

Next, as shown in step 22, check whether each of the scanning lines 40 produces a plurality of sensing values 61 greater than a threshold value 60, if so, proceed to step 23, such as the sensing values of the two scanning lines 41, 42 in Fig. 4 61 are greater than the threshold 60. In this preferred embodiment, the above-mentioned induction value 61 is not actually measured capacitance value, resistance value, inductance value in general design, but will be converted into equivalent circuit, measured voltage, current...etc. A method, because this is not the feature of the present invention, so it will not be described in detail here; and the scanning method of the scanning line 40 carried out on the touch panel 4 is aimed at the scanning lines in a sequential manner. 40 is detected and scanned one by one, such as scanning the odd-numbered scanning lines 40 first, and then scanning the even-numbered scanning lines 40, or all the scanning lines 40 are fully and simultaneously subjected to detection scanning, so it is generally related to the background of the field Those disclosed in the preferred embodiments are easy to be changed and used, and therefore should not be limited to those disclosed in the preferred embodiments.

It should be added that in step 22 , if no sensing value 61 greater than the threshold value 60 is detected in each of the scanning lines 40 , then return to step 21 and continue scanning the scanning lines 40 . However, the threshold value 60 mentioned here refers to the change value generated by the sensing quantity (voltage, current, etc.) of the touched position when the finger 71 of the user touches the touch panel 4 . A reference set value that is measured, averaged, and evaluated.

Then, as shown in step 23 , it is checked whether there are at least two adjacent scanning lines 40 among the scanning lines 40 whose sensing values 61 are greater than the threshold value 60 .

If the above judgment is "yes", then as shown in step 25, find out the corresponding at least one scanning line group 45, and according to the number of the group 45, determine that there are corresponding scanning lines 40 on the scanning lines 40. The reference finger of the group 45 touches 46, and proceeds to step 26; for example, the sensing value 61 of one scanning line 41 in FIG. 4 is greater than the threshold value 60, while another scanning line adjacent to the scanning line 41 The sensing value 61 of 42 is also greater than the threshold value 60, which means that a group 45 is found; and if a total of three groups are found on these scanning lines 40, each of which has at least two adjacent scanning lines 40 with a value greater than When the sensing value 61 of the threshold value 60 means that three groups 45 are formed, that is, there are three reference finger touches 46 .

It is worth mentioning that, if it is found that those scanning lines 40 whose sensing values 61 are greater than the threshold value 60 are not adjacent to each other during the inspection of the above-mentioned step 23, then all the scanning lines 40 on the above-mentioned scanning lines 40 will be The generated induction value 61 is determined to be noise 400 as shown in step 24 of FIG. The application of this method is because the fingers 71 of ordinary people will form an area of pressing contact on the touch panel 4 when they touch the touch panel 4, that is, at least two or more adjacent scanning lines 40 will be pressed at the same time, so that The (group of) adjacent scan lines 40 that are pressed produce changes in capacitance or resistance inductance. Therefore, in this preferred embodiment, if it is judged that this is not a physical finger 71 touch, but When it is caused by a noise 400 , the present invention will further ignore and filter the noise 400 , and return to step 21 to continue scanning the equal scan lines 40 .

Then, as shown in step 26, check whether the number of scan lines 40 of the sensing value 61 generated in the reference finger touch 46 is not greater than a reference value, if so, each of the reference finger touches 46 is a real finger touch 47, If not, each reference finger touch 46 includes a plurality of real finger touches 47 .

Step 26 will be further explained here. In this preferred embodiment, even when two fingers 71 close together as shown in FIG. The discrimination method of 25 can only define a reference finger touch 46 (that is, a group 45), but by step 26, each reference finger touch 46 can be further analyzed, for example, after determination, When the number of scanning lines 40 that the real finger 71 of a common person usually touches does not exceed 3, and the above-mentioned reference value is set to three, therefore, when a reference finger touches the scanning line of the induction value 61 generated in the 46 is detected When the number of 40 exceeds three, it can be analyzed that the reference finger touch 46 contains more than one real finger touch 47 .

Finally, as shown in step 27, each center of gravity position 48 is calculated according to the determined sensing value 61 in each of the real finger touches 47, and each center of gravity position 48 is marked as a finger touch source. In this preferred embodiment, the method for obtaining the center of gravity position 48 is to first mark the weight of each scan line 40, and then multiply the sensing value in each group with the threshold value. The sensing variation generated on the scanning line 40 (such as current, voltage, etc.) is added and then divided by the sum of all sensing variations, so that the touch panel 4 has scanning numbers 1 to 8 in sequence line 40, and its weight is also 1 to 8, and among these scanning lines 40, only the scanning lines 40 numbered 2 and 3 in a group 45 have capacitance changes, and when the sensing change values are all 0.5, then Its center of gravity position 48 is (2×0.5+3×0.5)/(0.5+0.5)=2.5, so the obtained center of gravity position 48 (that is, the aforementioned finger touch source) is 2.5, which is at number 2 and the middle of the scanning line 40 numbered 3, however, in practical applications, it can also be regarded as adding the coordinate positions of adjacent scanning lines 40 each having a sensing value 61 greater than the threshold value 60, and then It is obtained simply by calculating the arithmetic mean or other calculation methods, so it should not be limited to the description of this embodiment.

Referring to Fig. 7, Fig. 8, Fig. 9 and Fig. 10, it is the second preferred implementation of the method for detecting multi-finger touch on the touch panel of the present invention, and the principle and structure used are roughly the same as the first preferred implementation The methods described in the example are the same, and the similarities will not be repeated. The difference is that the scanning lines on the touch panel 4 are set in a two-dimensional manner, that is to say, the touch panel of this preferred embodiment The control board 4 includes a plurality of first scan lines 402 and a plurality of second scan lines 401 interlaced with the first scan lines 402, and the method includes the following steps:

First, as shown in step 301 , the first scan line 402 and the second scan line 401 are scanned.

It is worth mentioning that the above-mentioned first scanning lines 402 or second scanning lines 401 are not necessarily parallel to each other, and the interlacing between the first scanning lines 402 and the second scanning lines 401 can be perpendicular to each other or not. This is because in practical applications, various touch panels 4 will have different shape changes.

Next, as shown in step 302, check whether the first scanning line 402 produces a plurality of induction values 61 greater than a threshold value 60, if so, proceed to step 33; if scanning each of the first scanning lines 402 does not check When the sensing value 61 is greater than the threshold value 60, return to step 31 and continue scanning the first and second scanning lines 402, 401.

Then, as shown in step 303 , it is checked whether there are at least two adjacent first scan lines 402 whose iso-inductance value 61 is greater than the threshold value 60 .

If the determination result of step 303 is “No”, then as shown in step 304 , the sensed value 61 is determined to be noise 400 .

And when the judgment result of step 303 is " yes ", then as shown in step 305, find out corresponding at least one scanning line first group 49, number 41 and 42 in the first scanning line 402 of Fig. 8 two As shown, two first groups 49 are defined.

Then go to step 307 to check whether the second scanning lines 401 generate a plurality of sensing values 61 greater than a threshold value 60 .

If the judgment result of step 307 is “No”, then as shown in step 306 , the sensing value 61 is also judged as noise 400 .

And when the judgment result of step 307 is “Yes”, proceed to step 309 , and then continue to check whether there are at least two adjacent second scanning lines 401 with the induction value 61 greater than the threshold value 60 .

If the judgment result of step 309 is “No”, then as shown in step 308 , it is judged that the induction value 61 generated on the first and second scanning lines 402 , 401 is noise 400 .

And when the judgment result of step 309 is "Yes", then as shown in step 310, find out the corresponding at least one scan line second group 50, as shown in the number 43 and 44 in the second scan line 401 of Fig. 7 As shown, a second group 50 is defined.

Next, as shown in step 311, it is compared whether the numbers of the first and second groups 49, 50 are equal, and if so, it is determined that there are corresponding groups on the first scanning lines 402 and the second scanning lines 401. The number of reference finger touches 46 of the first group 49, if not, then the reference finger touches 46 determined by the number of groups with a smaller number. For example, when two first groups 49 are defined on the first scanning lines 402, but only one second group 50 is defined on the second scanning lines 401, since the second The number of the group 50 is smaller than the number of the first group 49 , so only one reference finger touch 46 can be determined.

Then, as shown in step 312, check whether the number of the first and second scanning lines 402, 401 of the sensing value 61 generated in the reference finger touch 46 is not greater than a reference value, if so, each of the reference finger touches 46 is is a real finger touch 47 , if not, each reference finger touch 46 includes a plurality of real finger touches 47 . In this preferred embodiment, the method of judging the number of reference finger touches 46 and real finger touches 47 is also the same as that described in step 26 in the first preferred embodiment above, so it will not be repeated here.

Finally, as shown in step 313 , the center of gravity positions 48 are calculated according to the determined sensing values 61 in each of the real finger touches 48 , and each center of gravity position is marked as a finger touch source. In this preferred embodiment, the determination of the center of gravity position 48 can refer to the relevant calculation description in step 27 in the aforementioned first preferred embodiment.

In addition, we can also apply the above-mentioned technical features mentioned in the first and second preferred embodiments to the extended function of the current touch panel 4, such as filtering out the noise 400 and judging that the real finger 71 is pressed, Using the above-mentioned method of finding the position of the center of gravity, the sensed position of the user's finger 71 is sent to a discrimination device (not shown), and then the discrimination device is used to further detect the user's finger 71 gesture to decide whether to accept or ignore the gesture, and to judge whether it is a continuous gesture or two separate gestures based on the time difference between the gestures received. Since the gesture judgment described here is not the technical focus of the present invention and is well known to those familiar with the relevant technical field, no more in-depth description of its application principle will be given here.

To sum up the above, the method for detecting multi-finger touch on the touch panel of the present invention, by setting the threshold value 60, and comparing with it, whether there are more than two adjacent scans of the finger 71 on the touch panel 4 The induction value 61 generated by the line 40 is greater than the threshold value 60 to determine whether the induction value 61 generated on the touch panel 4 is generated by the finger 71 or just the noise 400, so as to effectively avoid interference due to the noise 400 The resulting misjudgment achieves a correct judgment of the state of the finger 71 on the touch panel 4, so the purpose of the present invention can indeed be achieved.

Claims (10)

1. A method for a touchpad to detect multi-finger touches, said touchpad comprising a plurality of scan lines, characterized in that said method comprises the following steps: (a), scanning the plurality of scan lines; (b), check whether each of the plurality of scanning lines produces a plurality of sensing values greater than a threshold value, if so, proceed to the next step; (c), check whether there are at least two adjacent scan lines whose sensing values are greater than the threshold value, and if so, find out the corresponding at least one group of two adjacent scanning lines whose sensing values are greater than the threshold value Scanning lines to form scanning line groups, and according to the number of groups, it is determined that the plurality of scanning lines have reference finger touches corresponding to the number of groups; (d), check whether the number of scanning lines of the induction value generated in the reference finger touch is not greater than a reference value, if so, each reference finger touch is a real finger touch, if not, each reference finger touch Includes multiple real finger touches; (e) Calculate the positions of the centers of gravity according to the determined sensing values of the real finger touches, and mark each position of the center of gravity as a finger touch source. 2. The method for detecting multi-finger touches on a touch panel according to claim 1, characterized in that in the method (c) step, if there is no gap between the plurality of scanning lines that generate sensing values adjacent, it is determined that the sensing values generated by the plurality of scan lines are noise. 3. The method for detecting multi-finger touches on a touch panel according to claim 1, characterized in that in the step (b) of the method, if the plurality of scanning lines are not detected to be greater than the threshold value If the sensor value is higher, repeat step (a). 4. The method for detecting multi-finger touches on a touch panel according to claim 1, characterized in that in the method (a), the method of scanning the plurality of scanning lines can be row by row or Interleaved skip scan. 5. A method for detecting multi-finger touches on a touch panel, the touch panel comprising a plurality of first scan lines and a plurality of second scan lines intersecting with the plurality of first scan lines, characterized in that Said method comprises the following steps: (a), scanning the plurality of first scanning lines and second scanning lines; (b), check whether the plurality of first scanning lines produce a plurality of sensing values greater than a threshold value, if so, proceed to the next step; (c) Check whether at least two of the plurality of first scan lines whose sensing values are greater than the threshold value are adjacent, if so, find the corresponding first group of at least one scan line, and proceed to the next step; (d), check whether the plurality of second scanning lines generate a plurality of sensing values greater than a threshold value, if so, proceed to the next step; (e), check whether the plurality of second scanning lines whose sensing values are greater than the threshold value are adjacent, and if so, find the corresponding second group of at least one scanning line; and (f), compare whether the numbers of the first group and the second group are equal; Reference finger touch, if not, use the smaller number of groups as the determined reference finger touch; (g), check whether the number of the first scanning line and the second scanning line of the induction value generated in the reference finger touch is not greater than a reference value, if so, each reference finger touch is a real finger touch, if not , then each reference finger touch includes multiple real finger touches; (h) Calculate the positions of the centers of gravity according to the determined sensing values in the real finger touches, and mark each position of the center of gravity as a finger touch source. 6. The method for detecting multi-finger touches on a touch panel according to claim 5, wherein in the step (c), if the plurality of first scanning lines that generate sensing values are not adjacent to each other, Then it is determined that the sensing values generated by the plurality of first scan lines are noise. 7. The method for detecting multi-finger touches on a touch panel according to claim 5, wherein in the step (e), if the plurality of second scanning lines that generate sensing values are not adjacent to each other, Then it is determined that the sensing values generated by the plurality of first scan lines and the second scan lines are noise. 8. The method for detecting multi-finger touches on a touch panel according to claim 5, characterized in that in step (b), if the plurality of first scan lines do not detect a value greater than the threshold value, When sensing a value, repeat step (a). 9. The method for detecting multi-finger touches on a touch panel according to claim 5, characterized in that in step (d), if the plurality of second scanning lines does not detect a sensing value greater than the threshold value value, it is determined that the sensing values generated by the plurality of first scan lines are noise, and step (a) is repeated. 10. The method for detecting multi-finger touches on a touch panel according to claim 5, characterized in that in the step (a), the scanning of the plurality of first scanning lines and the second scanning lines can be done one by one Row or cross skip scan.

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