WO2014086211A1 - Method, system, and touch terminal for updating standard of touch screen - Google Patents

Abstract

The present invention relates to the technical field of touch, and provides a method for updating a standard of a touch screen, comprising: backuping characteristic values at a stable state; using sampled original values of the electrified touch screen as standard values to establish a standard, and calculating characteristic values at the electrified state; calculating a difference between each backuped characteristic value and each characteristic value at the electrified state to obtain absolute values, and finding the maximum value from the absolute values; determining whether the maximum value is greater than a set first threshold; and if the maximum value is greater than the set first threshold, determining that the current standard is incorrect; if the current standard is incorrect, determining whether the touch screen is touched; and if there is no touch, updating the standard at regular time, and if there is a touch, timely monitoring whether the current characteristic values obtained according to the currently sampled original values are consistent with the backuped characteristic values; and if the current characteristic values are consistent with the backuped characteristic values, updating the standard. Through the present invention, during practical detection of the touch control chip, the correct standard value can be fast obtained, and then the standard is accurately updated.

Description

 Touch screen reference updating method, system and touch terminal

Technical field

 The present invention relates to the field of touch technologies, and in particular, to a method and system for updating a reference of a touch screen and a touch terminal. Background technique

 With the development of touch technology and terminal technology, more and more terminal devices use touch control for human-computer interaction. At present, the touch screens used in terminal devices mainly include a capacitive touch screen and a resistive touch screen. Among them, the capacitive touch screen has been favored by more and more users for its good definition, light transmittance and touch.

 In the process of detecting touch, the touch control chip first samples the original data through an ADC (Analog-to-Digital Converter) to obtain the original value; then establishes a reference according to the original value to obtain a reference value; In the calculation, the original value is subtracted from the reference value to obtain the difference, and the coordinate value can be calculated from the difference. In order to get the correct difference, it is necessary to maintain a correct reference, that is, the original value used to establish the reference should be the original value sampled when the capacitive touch screen is in a stable state. The steady state means that there is no finger on the capacitive touch screen. Touching a pen, water droplets, etc. will change the state of the object of the original value. In actual use, the capacitive touch screen may have water droplets, sweat, and touch on the screen, so that the obtained reference is incorrect, resulting in poor sensitivity or false alarm of the touch screen. The report point means that there is actually no touch at a certain position on the capacitive touch screen and the touch control chip calculates the coordinates.

Specifically, after the power system is powered on, it is necessary to establish an initial reference, that is, the original value of the first sampling after power-on is directly used as the reference value; after the initial reference is established, in the subsequent sampling calculation, according to the difference The data of the value changes regularly, and the reference is updated. The original reference is used as the reference value, and the subsequent sample calculation is based on the original value of the current reference. As shown in Figure 1, for the working flow chart of the capacitive touch screen, the touch control chip first obtains the original value through ADC sampling, and determines whether it is the first sampling after power-on. If yes, the original value of the current sampling is used as a reference. Otherwise, Benchmark and original The starting value is difference, then the coordinates are calculated, and then the data is changed according to the difference data to determine whether the reference needs to be updated. If necessary, the original value of the current sampling is used as a reference. Otherwise, the process ends and continues to the next time. sampling. When the system is powered on, it is impossible to determine whether there are fingers or water droplets on the screen at this time, which will cause a wrong reference to be obtained when there are fingers or water droplets on the screen, and in the subsequent processing, when the finger leaves or drops After drying, you should be able to quickly update the baseline. If the screen is in a stable state during power-on, and during subsequent use, due to environmental changes on the screen, such as temperature changes, or water droplets or sweat on the screen, in order to enable the capacitive touch screen to operate normally, it needs to be dynamically changed according to environmental changes. Update the baseline. For example, when the temperature of the capacitive screen changes with the temperature of the environment, the original value of the sample will change accordingly. At this time, the reference needs to be updated every time to avoid insensitive or false alarm points. If the acquired reference is incorrect during the reference update, the sensitivity of the touch screen may be deteriorated or the false alarm point may occur. Therefore, how to correctly obtain the reference value is the key to whether the capacitive touch screen touch control chip can be detected normally. Summary of the invention

 The present invention is directed to the above-described drawbacks of the prior art, and provides a method for updating a reference of a touch panel, which can quickly and accurately acquire a correct reference value, thereby correctly updating the reference. The invention adopts the following technical solutions:

 A method for updating a reference of a touch screen, the method comprising the following steps:

 When the touch screen is in a stable state, the sampling points are sampled, and the original values of the stable state samples are obtained, and the characteristic values of the sampling points of the touch screen are calculated and backed up according to the original values of the stable state samples, to obtain the backup feature values;

 The touch screen is powered on, sampling each sampling point, obtaining the original value of the power-on sampling, using the original value of the power-on sampling as a reference value to establish a reference, and calculating, according to the original value of the power-on sampling, the touch screen The power-on feature value of the sampling point;

 Determining the power-on feature value and the backup feature value and taking an absolute value to find a maximum value among the absolute values;

Determining whether the maximum value is greater than a set first threshold, if the maximum value is greater than a set first Threshold, it is determined that the current reference is incorrect;

 If the current reference is incorrect, determine whether there is a touch on the touch screen. If there is no touch, the reference is updated periodically. If there is a touch, the change of the original value of the current sample is monitored in real time, and the reference is updated when the original value of the current sample meets the baseline update condition. .

 The invention also provides a reference update system for a touch screen, comprising:

 a sampling unit, configured to sample each sampling point to obtain a sampled original value;

 a calculating unit, configured to calculate, according to an original value of the steady state sampling, a feature value of each sampling point of the touch screen, and calculate a current feature value of each sampling point of the touch screen according to the original value of the sampling time at the time of powering on the touch screen and after power-on, and Determining the current feature value from the backup feature value and taking an absolute value to find the maximum value among the absolute values;

 a backup unit, configured to back up a feature value in a steady state, and obtain a backup feature value;

 a reference value establishing unit, configured to use a raw value sampled when the touch screen is powered on as a reference value to establish a reference;

 a determining unit, configured to determine whether a maximum value calculated according to sampling when the touch screen is powered on is greater than a set first threshold, and if the maximum value is greater than a set first threshold, determining that the current reference is incorrect, and Determine if there is a touch on the touch screen when the reference is incorrect;

 a reference value updating unit, configured to periodically update the reference when the current reference is incorrect and there is no touch on the touch screen, and update the reference when the current reference is incorrect, there is a touch on the touch screen, and the original sampled original value meets the baseline update condition;

 The monitoring unit is configured to monitor the change of the original value of the current sample in real time when the current reference is incorrect and there is a touch on the touch screen.

 The invention also provides a touch terminal, wherein the touch terminal comprises a reference update system of the touch screen.

The invention compares the sampled value with the backup feature value by backing up the feature value in the steady state of the touch screen, and judges the correctness of the reference, so that the touch control chip can quickly and accurately obtain the correct reference value during the actual detection. Thereby the benchmark is updated correctly. DRAWINGS

 Figure 1 is a working flow chart of a capacitive touch screen;

 2 is a flowchart of a method for updating a reference of a touch screen of Embodiment 1;

 3 is a flow chart showing a method for updating a reference when the determination criterion is incorrect in the embodiment 1 and the touch screen has a touch;

 4 is a flowchart of a method for updating a reference of a touch screen of Embodiment 2;

 5 is a flow chart showing a method for updating a reference when the determination criterion is incorrect in the embodiment 2 and the touch screen has a touch;

 6 is a flowchart of a method for updating a reference of a touch screen of Embodiment 3;

 7 is a flow chart showing a method for updating a reference when the determination criterion is incorrect in the embodiment 3 and the touch screen has a touch;

 Fig. 8 is a block diagram showing the structure of a reference updating system of the touch panel of the fourth embodiment. detailed description

 The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

 The embodiment of the present invention compares the sampled value with the backup feature value by backing up the feature value in the steady state of the touch screen, and determines the correctness of the reference, so that the touch control chip can quickly and accurately obtain the correct reference during the actual detection. The value, thus correctly updating the baseline. The feature value may be a difference value between the original values of the adjacent sampling point samples of the touch screen, a ratio between the original values of the adjacent sampling points of the touch screen, or an original value sampled by each sampling point of the touch screen. The technical solutions of the present invention are described in detail below by taking the above three kinds of characteristic values as examples.

 Example 1:

In this embodiment, the feature value is a difference value between original values of adjacent sampling points of the touch screen. Referring to FIG. 2, it is a flowchart of a method for updating a reference of a touch screen according to Embodiment 1 of the present invention. The method comprises the following steps: Step S101: Stable state sampling, and calculating a difference value of adjacent sampling points in a steady state and backing up.

 In this step, when the touch screen is in a steady state, each sampling point is sampled, and the original value of the steady state sampling is obtained, and then the difference value between the original values of the adjacent sampling points of the touch screen is calculated according to the original value of the stable state sampling, and the difference is backed up. The differential value, as a reference quantity for the reference update, enables the touch control chip to quickly and accurately acquire the correct reference value when actually detecting it. The differential value can be backed up in a non-volatile memory of the touch control chip, such as Flash Memory, PROM (Programmable read-only memory), EAROM (Electrically alterable read only memory) Rewriting the read only memory), EPROM (Erasable programmable read only memory) or EEPROM (Electrically erasable programmable read only memory), etc. The value backup is stored in the flash memory of the touch control chip.

 The following examples are given. If the capacitive touch screen is in the steady state, the original values sampled are as shown in the following table, where the first behavior is the sampling point number, and the second behavior is the original value of each sampling point:

Raw value of steady state sampling

 At this time, the touch control chip backs up the reference reference in the Flash Memory, and stores the difference value between the original values sampled by the adjacent sampling points of the touch screen in the steady state in the Flash Memory, that is, the backup differential value back_diff[i]=S[i+ l]-S[i], where back_diff[i] is abbreviated as B[i], as shown in the following table:

Table 2 Backup differential values

There are two ways to establish this backup. One is that before the touch screen is shipped from the factory, when the factory ensures that there is no touch on the screen and is in a stable state, the current reference value is made worse, and back_diff[i] is obtained, and the other is out. The factory does not perform calibration, and it is obtained through automatic learning of the software during the use of the product. This method is more complicated than the first method.

 Step S102: Power-on sampling, establish a reference, and calculate a difference value of adjacent sampling points at power-on. In this step, after the touch screen is powered on, each sampling point is sampled, the original value of the power-on sampling is obtained, the original value of the power-on sampling is used as a reference value to establish a reference, and the touch screen phase is calculated according to the original value of the power-on sampling. The difference between the original values of the adjacent sample points.

 If the system has water on the screen before power-on, and the original value of the first sampling at power-on is as shown in the following table, the wrong reference will be obtained after power-on:

Original value sampled at power-on

 The difference between the original values of the adjacent sample points sampled as the reference at this time is as follows:

Table 4 Difference values sampled at power-on

 Step S103: Difference between the difference value at the time of power-on and the backup difference value and take an absolute value to find the maximum value in the absolute value.

 In this embodiment, it is determined whether the current reference is correct by comparing the degree of similarity between the difference value of the current reference adjacent sampling point of the power-on and the backup difference value in the Flash Memory. Specifically, the degree of similarity is compared by making the difference between the two and taking the absolute value. In this step, compare the difference value sampled at power-on in Table 4 with the backup difference value in Table 2 Flash Memory and take the absolute value to find the maximum value in the absolute value.

 Step S104: Determine whether the maximum value is greater than the first threshold. If yes, execute step S105. Otherwise, the reference is correct, and the process ends, and the normal touch workflow is performed.

In this step, it is determined whether the current reference is positive by comparing the maximum value with the set threshold. Indeed. The first threshold is set according to the actual debugging result in the design process, and can be no longer changed after being set.

 Step S105: The current reference is incorrect.

 The maximum value is greater than the first threshold, indicating that the current baseline is incorrect at this time.

 Step S106: It is judged whether there is a touch, and if so, step S107 is performed, otherwise, step S108 is performed. When the current reference is incorrect, continue to determine if there is a touch on the touch screen. Specifically, it can be judged by the following methods:

 Sampling each sampling point, obtaining the original value of the current sampling, and subtracting the original value of the current sampling from the current reference value to obtain a difference;

 Determining whether the difference is less than a set second threshold;

 If the difference is less than the set second threshold, it is determined that there is no touch, otherwise, it is determined that there is a touch. The second threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set.

 Step S107: Real-time monitoring of the change of the original sampled value, and updating the reference when the original sampled original value meets the baseline update condition.

 When the touch screen has a touch, it is necessary to monitor the change of the original value of the current sample in real time. When the original value of the current sample meets the reference update condition, it indicates that the current original value is more suitable for the reference reference quantity, and the reference needs to be updated immediately. The benchmark is replaced. The reference update condition may be set according to actual conditions, and is not limited to one type. For example, the difference between the current feature value and the reference feature value and the backup feature value may be calculated, and if the difference between the current feature value and the backup feature value is greater than the reference If the difference between the eigenvalue and the backup eigenvalue is small, and the amount of change between the two differences exceeds a set value, the original value of the current sample is considered to be in accordance with the reference update condition, and is more suitable for the reference. Update the benchmark. The specific method is shown in Figure 3:

 Step A101: Determine whether the reference is incorrect and touched. If yes, go to step A102. Otherwise, end the process and follow the normal touch workflow.

Step A102: Sampling, calculating a difference value of the current adjacent sampling point and calculating a reference difference value according to the reference value. In this step, each sampling point is sampled, and the original value of the current sampling is obtained, and the difference value between the original values of the adjacent sampling points of the current touch screen is calculated according to the original value of the current sampling, that is, diff_cur[i]=rawdata[i+l ]-rawdata[i] _; and calculate the difference value between the reference values of the adjacent sampling point samples of the touch screen according to the reference value, that is, diff_ref[i]= refdata[i+l]- refdata[i].

 Step A103: The current difference value and the reference difference value are respectively compared with the backup difference value and taken as an absolute value.

The difference value between the original values of the adjacent sampling points of the current touch screen is compared with the backup difference value and takes an absolute value, that is, diff_c[i]=Abs(diff_cur[i]-back_diff[i]) _; and the touch screen phase The difference value between the reference values sampled by the adjacent sample points is compared with the backup difference value and takes an absolute value, that is, diff_r[i]=Abs(diff_ref[i] -back_diff[i]).

 Step A104: Find the maximum of the two sets of absolute values, respectively.

 This step separately calculates the maximum value of the absolute values of the two sets of differences, wherein the maximum value in diff_c[i] is the first maximum value diff_cmax, and the maximum value in diff_r[i] is the second maximum value diff_rmax.

 Step A105: Determine whether the first maximum value is smaller than the second maximum value. If yes, go to step A106, otherwise, go back to step A102.

 In this step, when the first maximum value diff_cmax is smaller than the second maximum value diff_rmax, it indicates that the current original value has gradually approached the backup value; otherwise, it indicates that the original sample value at this time does not get better and needs to be resampled.

 Step A106: Determine whether the absolute value of the difference between the second maximum value and the first maximum value is greater than the third threshold. If yes, go to step A107, otherwise, go back to step A102.

 In this step, it is determined whether the original value of the current sample conforms to the reference update condition by further comparing the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax with a set threshold value. The third threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set. If the difference between the second maximum value diff_rmax and the first maximum value diff_cmax does not exceed the third threshold value, it indicates that the sample original value at this time does not meet the reference update condition and needs to be resampled.

 Step A107: There is a false positive point, and the baseline is forced to be updated.

When the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax is greater than the setting The third threshold indicates that the current value is the original value without the touch state, the current touch is the false alarm point, the touch operation is not performed at this time, and the reference is forced to be updated once, thereby eliminating the false alarm point and restoring the correct reference.

 Step S108: The reference is updated periodically.

 If there is no touch, the original reference value of the current sample is replaced with the current reference value to update the reference every predetermined time interval.

 In this embodiment, by comparing the difference value between the original values sampled by the adjacent sampling points of the touch screen when the state is backed up, the difference between the original values of the samples sampled at the time of power-on and after power-on is compared with the difference value of the backup. Therefore, judging the correctness of the reference enables the touch control chip to quickly and accurately acquire the correct reference value during the actual detection, thereby correctly updating the reference.

 Example 2:

 In this embodiment, the feature value is a proportional value between the original values sampled by adjacent sampling points of the touch screen. Please refer to FIG. 4, which is a flowchart of a method for updating a reference of a touch screen according to Embodiment 2 of the present invention. The method includes the following steps:

 Step S201: Stable state sampling, and calculating the ratio of the adjacent sampling points in the steady state and preparing for the backup.

 In this step, when the touch screen is in a steady state, each sampling point is sampled, and the original value of the steady state sampling is obtained, and then the ratio between the original values of the adjacent sampling points of the touch screen is calculated according to the original value of the stable state sampling, and the ratio is backed up. The proportional value, as a reference quantity for the reference update, enables the touch control chip to quickly and accurately obtain the correct reference value when actually detecting. The ratio is the ratio between the original values of adjacent sample points sampled by a set multiple. In this embodiment, the scale value backup is stored in the Flash Memory of the touch control chip.

 The following examples are given. If the capacitive touch screen is in the steady state, the original values sampled are as shown in the following table, where the first behavior is the sampling point number, and the second behavior is the original value of each sampling point:

 Raw value of steady state sampling

No. so SI S2 S3 S4 S5 S6 S7 S8 S9 The original value is 2100 2050 1900 1950 2010 2200 1920 2010 2300 2100 At this time, the touch control chip backs up the reference datum in the Flash Memory, and stores the scale value between the original values sampled by the adjacent sampling points of the touch screen in the steady state in the Flash Memory, because The MCU (Micro Control Unit) is difficult to process the decimal. The result of the ratio is enlarged by a set multiple to obtain an integer. The magnification of the setting can be adjusted according to the actual situation, such as but not limited to the ratio. The result is magnified S[0] times, that is, the backup scale value back_diff[i]=(S[i+l]/S[i])*S[0], where back_diff[i] is abbreviated as B[i], as follows The table shows:

 There are two ways to establish this backup. One is that before the touch screen is shipped from the factory, the factory makes the current reference value worse when it is not touched and stable in the screen, and gets back_diff[i], and the other is shipped. Without calibration, it is obtained through automatic learning of the software during the use of the product, which is more complicated than the first method.

 Step S202: Power-on sampling, establish a reference, and calculate a ratio of adjacent sampling points at power-on. In this step, after the touch screen is powered on, each sampling point is sampled, the original value of the power-on sampling is obtained, the original value of the power-on sampling is used as a reference value to establish a reference, and the touch screen phase is calculated according to the original value of the power-on sampling. The ratio between the original values of the adjacent sample points.

 If the system has water on the screen before power-on, and the original value of the first sampling at power-on is as shown in the following table, the wrong reference will be obtained after power-on:

Original value sampled at power-on

At this time, the ratio between the original values of the adjacent sample points sampled as the reference is as follows (already placed Proportional value sampled at power-on

 Step S203: The difference between the proportional value at the time of power-on and the backup ratio value is taken and the absolute value is taken to find the maximum value in the absolute value.

 In this embodiment, it is determined whether the current reference is correct by comparing the degree of similarity between the ratio of the current reference adjacent sampling point of the power-on and the backup ratio value in the Flash Memory. Specifically, the degree of similarity is compared by making the difference between the two and taking the absolute value. In this step, the ratio of the sampled value at power-on in Table 8 is compared with the backup ratio value in Table 6 Flash Memory and the absolute value is taken to find the maximum value in the absolute value.

 Step S204: It is determined whether the maximum value is greater than the first threshold. If yes, step S205 is performed. Otherwise, the reference is correct, and the process ends, and the normal touch workflow is performed.

 In this step, it is determined whether the current reference has been determined by comparing the maximum value with a set threshold. The first threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set.

 Step S205: The current reference is incorrect.

 The maximum value is greater than the first threshold, indicating that the current baseline is incorrect at this time.

 Step S206: It is judged whether there is a touch, and if so, step S207 is performed, otherwise, step S208 is performed. When the current reference is incorrect, continue to determine if there is a touch on the touch screen. Specifically, it can be judged by the following methods:

 Sampling each sampling point, obtaining the original value of the current sampling, and subtracting the original value of the current sampling from the current reference value to obtain a difference;

 Determining whether the difference is less than a set second threshold;

If the difference is less than the set second threshold, it is determined that there is no touch, otherwise, it is determined that there is a touch. The second threshold is set according to the actual debugging result in the design process, and can be no longer changed after being set. Step S207: The change of the original value of the current sample is monitored in real time, and the reference is updated when the original value of the current sample meets the reference update condition.

 When the touch screen has a touch, it is necessary to monitor the change of the original value of the current sample in real time. When the original value of the current sample meets the reference update condition, it indicates that the current original value is more suitable for the reference reference quantity, and the reference needs to be updated immediately. The benchmark is replaced. The reference update condition may be set according to actual conditions, and is not limited to one type. For example, the difference between the current feature value and the reference feature value and the backup feature value may be calculated, and if the difference between the current feature value and the backup feature value is greater than the reference If the difference between the eigenvalue and the backup eigenvalue is small, and the amount of change between the two differences exceeds a set value, the original value of the current sample is considered to be in accordance with the reference update condition, and is more suitable for the reference. Update the benchmark. The specific method is shown in Figure 5:

 Step A201: Determine whether the reference is incorrect and touched. If yes, go to step A202. Otherwise, end the process and follow the normal touch workflow.

 Step A202: Sampling, calculating a proportional value of the current adjacent sampling point and calculating a reference proportional value according to the reference value.

 In this step, each sampling point is sampled, and the original value of the current sampling is obtained, and the ratio between the original values of the adjacent sampling points of the current touch screen is calculated according to the original value of the current sampling, that is, prop_cur[i]=rawdata[i+l ]/rawdata[i]*rawdata[0] ; and calculate the ratio between the reference values of the adjacent sampling points of the touch screen according to the reference value, ie prop_ref[i]=refdata[i+l]/refdata[i] * refdata[0].

 Step A203: The current scale value and the reference scale value are respectively compared with the backup scale value and take an absolute value.

The difference between the original value of the sampling of the adjacent sampling points of the current touch screen is compared with the backup ratio value and takes an absolute value, that is, diff_c[i]=Abs(prop_cur[i]-back_prop[i]) _; and the touch screen phase The ratio between the reference values of the adjacent sample points is compared with the backup ratio value and takes the absolute value, that is, diff_r[i]=Abs(prop_ref [i] -back_prop [i] ).

 Step A204: Find the maximum of the two sets of absolute values, respectively.

This step separately counts the maximum of the absolute values of the two sets of differences, where the maximum value in diff_c[i] is The maximum value of the first maximum value diff_cmax, diff_r[i] is the second maximum value diff_rmax. Step A205: Determine whether the first maximum value is smaller than the second maximum value, and if yes, execute step A206, otherwise, return to step A202.

 In this step, when the first maximum value diff_cmax is smaller than the second maximum value diff_rmax, it indicates that the current original value has gradually approached the backup value; otherwise, it indicates that the original sample value at this time does not get better and needs to be resampled.

 Step A206: Determine whether the absolute value of the difference between the second maximum value and the first maximum value is greater than the third threshold. If yes, go to step A207, otherwise, go back to step A202.

 In this step, it is determined whether the original value of the current sample conforms to the reference update condition by further comparing the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax with a set threshold value. The third threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set. If the difference between the second maximum value diff_rmax and the first maximum value diff_cmax does not exceed the third threshold value, it indicates that the sample original value at this time does not meet the reference update condition and needs to be resampled.

 Step A207: There is a false positive point, and the baseline is forced to be updated.

 When the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax is greater than the set third threshold value, the current value is the original value without the touch state, and the current touch is a false alarm point, and is not executed at this time. Touch the action and force a baseline update to eliminate false positives and restore the correct baseline.

 Step S208: The reference is updated periodically.

 If there is no touch, the original reference value of the current sample is replaced with the current reference value to update the reference every predetermined time interval.

 In this embodiment, by comparing the ratio between the original values sampled by the adjacent sampling points of the touch screen in the steady state, the ratio between the original values of the samples sampled at the time of power-on and after power-on is compared with the ratio of the backup. Therefore, judging the correctness of the reference enables the touch control chip to quickly and accurately acquire the correct reference value during the actual detection, thereby correctly updating the reference.

 Example 3:

In this embodiment, the feature value is the original value sampled by each sampling point of the touch screen. Please refer to Figure 6, A flowchart of a method for updating a reference of a touch screen according to Embodiment 3 of the present invention. The method includes the following steps: Step S301: Stable state sampling, and obtaining the original values sampled by each sampling point in the steady state and backing up. In this step, when the touch screen is in a steady state, each sampling point is sampled, and the original value of each sampling point sample in a steady state is obtained, and the original value is backed up as a reference quantity of the reference update, so that the touch control chip can be quickly and accurately detected in actual detection. Get the correct reference value. In this embodiment, the original value is backed up and stored in the Flash Memory of the touch control chip. In this embodiment, the original value of the sample is directly used as the backup feature value without performing complicated calculation.

 The following examples are given. If the capacitive touch screen is in the steady state, the original values sampled are as shown in the following table, where the first behavior is the sampling point number, and the second behavior is the original value of each sampling point:

Raw value of steady state sampling

 At this time, the touch control chip backs up the reference reference in the Flash Memory, and stores the original value sampled by the adjacent sampling points of the touch screen in the steady state in the Flash Memory, that is, the backup original value back_diff[i]=S[i], where back_diff[i ] abbreviated as B[i], as shown in the following table:

Table 10 Backup original values

 There are two ways to establish this backup. One is that before the touch screen is shipped from the factory, the factory makes the current reference value worse when it is not touched and stable in the screen, and gets back_diff[i], and the other is shipped. Without calibration, it is obtained through automatic learning of the software during the use of the product, which is more complicated than the first method.

Step S302: Power-on sampling, and obtain the original value sampled by each sampling point at the time of power-on, and establish a reference. In this step, after the touch screen is powered on, each sampling point is sampled, and the original value of the power-on sampling is obtained, and the original value of the power-on sampling is used as a reference value to establish a reference. If the system has water on the screen before power-on, and the original value of the first sampling at power-on is as shown in the following table, the wrong reference will be obtained after power-on:

Table 11 Raw values sampled at power-on

 Step S303: The difference between the original value at the time of power-on and the original value of the backup is taken and the absolute value is taken to find the maximum value in the absolute value.

 In this embodiment, it is determined whether the current reference is correct by comparing the similarity between the original value of each sampling point of the current reference and the original value of the backup in the Flash Memory. Specifically, the degree of similarity is compared by making the difference between the two and taking the absolute value. In this step, the original value sampled at power-on in Table 11 is compared with the original value of the backup in Table 10 Flash Memory and its absolute value is taken to find the maximum value in the absolute value, as shown in the following table:

 Step S304: Determine whether the maximum value is greater than the first threshold. If yes, execute step S305. Otherwise, the reference is correct, and the process ends, and the normal touch workflow is performed.

 In this step, it is determined whether the current reference has been determined by comparing the maximum value with a set threshold. The first threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set.

 Step S305: The current reference is incorrect.

 The maximum value is greater than the first threshold, indicating that the current baseline is incorrect at this time.

 Step S306: It is judged whether there is a touch, and if so, step S307 is performed, otherwise, step S308 is performed. When the current reference is incorrect, continue to determine if there is a touch on the touch screen. Specifically, it can be judged by the following methods:

Sampling each sample point, obtaining the original value of the current sample, subtracting the current sample from the current reference value The original value gets the difference;

 Determining whether the difference is less than a set second threshold;

 If the difference is less than the set second threshold, it is determined that there is no touch, otherwise, it is determined that there is a touch. The second threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set.

 Step S307: The change of the original value of the current sample is monitored in real time, and the reference is updated when the original value of the current sample meets the baseline update condition.

 When the touch screen has a touch, it is necessary to monitor the change of the original value of the current sample in real time. When the original value of the current sample meets the reference update condition, it indicates that the current original value is more suitable for the reference reference quantity, and the reference needs to be updated immediately. The benchmark is replaced. The reference update condition can be set according to the actual situation, and is not limited to one type, for example, by calculating the difference between the original value of the current sample and the reference value and the original value of the backup, if the difference between the original value of the current sample and the original value of the backup If the value is smaller than the difference between the reference value and the original value of the backup, and the amount of change between the two differences exceeds a set value, the original value of the current sample is considered to be in accordance with the reference update condition, and is more suitable as a reference. The baseline can be updated. The specific method is shown in Figure 7:

 Step A301: Determine whether the reference is incorrect and touched. If yes, go to step A302. Otherwise, end the process and follow the normal touch workflow.

 Step A302: Sampling, and obtaining the original value of each current sampling point.

 In this step, each sampling point is sampled, and the original value rawdata[i] of each sampling point is obtained.

Step A303: The current original value and the reference value are respectively compared with the original backup value and the absolute value is taken. The original value of each sampling point of the current touch screen is compared with the original value of the backup and takes an absolute value, that is, diff_c[i]=Abs(rawdata[i]-back_base[i]) _; and the reference value of each sampling point of the touch screen is Back up the original value and make the difference and take the absolute value, ie diff_r[i]=Abs(refdata[i]-back_diff[i]).

 Step A304: Find the maximum of the two sets of absolute values, respectively.

 This step separately calculates the maximum value of the absolute values of the two sets of differences, wherein the maximum value in diff_c[i] is the first maximum value diff_cmax, and the maximum value in diff_r[i] is the second maximum value diff_rmax.

Step A305: determining whether the first maximum value is smaller than the second maximum value, and if yes, performing step A306. Otherwise, return to step A302.

 In this step, when the first maximum value diff_cmax is smaller than the second maximum value diff_rmax, it indicates that the current original value has gradually approached the backup value; otherwise, it indicates that the original sample value at this time does not get better and needs to be resampled.

 Step A306: Determine whether the absolute value of the difference between the second maximum value and the first maximum value is greater than a third threshold. If yes, go to step A307, otherwise, go back to step A302.

 In this step, it is determined whether the original value of the current sample conforms to the reference update condition by further comparing the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax with a set threshold value. The third threshold is set according to the actual debugging result during the design process, and can be no longer changed after being set. If the difference between the second maximum value diff_rmax and the first maximum value diff_cmax does not exceed the third threshold value, it indicates that the sample original value at this time does not meet the reference update condition and needs to be resampled.

 Step A307: There is a false positive point, and the baseline is forced to be updated.

 When the absolute value of the difference between the second maximum value diff_rmax and the first maximum value diff_cmax is greater than the set third threshold value, the current value is the original value without the touch state, and the current touch is a false alarm point, and is not executed at this time. Touch the action and force a baseline update to eliminate false positives and restore the correct baseline. Step S308: The reference is updated periodically.

 If there is no touch, the original reference value of the current sample is replaced with the current reference value to update the reference every predetermined time interval.

 In this embodiment, by comparing the original values sampled by the sampling points of the touch screen during the steady state, the original values of the sampling points at the time of power-on and after power-on are compared with the original values of the backup, and the correctness of the reference is judged, so that the touch control is performed. When the chip is actually detected, it can quickly and accurately obtain the correct reference value, so as to correctly update the reference.

 Example 4:

This embodiment provides a reference update system for a touch screen. As shown in FIG. 8, the system includes: a sampling unit 1, a computing unit 2, a backup unit 3, a reference value establishing unit 4, a determining unit 5, and a reference value updating unit 6. And monitoring unit 7. The sampling unit 1 is configured to sample each sampling point to obtain the original value of the sampling; the calculating unit 2 is configured to calculate the sampling points of the touch screen according to the original value of the stable state sampling. The eigenvalue is calculated according to the original value of the sampling time at the time of powering on the touch screen and at each time point after power-on, and the current feature value is compared with the backup feature value and the absolute value is taken to find the absolute value. The maximum value of the value; the backup unit 3 is used to back up the feature value in the steady state, and the backup feature value is obtained; the reference value establishing unit 4 is configured to use the original value sampled when the touch screen is powered on as a reference value to establish a reference; And determining whether the maximum value calculated according to the sampling when the touch screen is powered on is greater than a set first threshold, and if the maximum value is greater than the set first threshold, determining that the current reference is incorrect, and determining that the current reference is incorrect Whether there is a touch on the touch screen; the reference value updating unit 6 is configured to periodically update the reference when the current reference is incorrect and there is no touch on the touch screen, and the current reference is incorrect, the touch screen has a touch, and the current sampled original value meets the reference update condition. Time update reference; monitoring unit 7 is used when the current reference is incorrect and there is a touch on the touch screen Monitor changes in the current value of the original sample.

 In this embodiment, the calculating unit 2 is further configured to subtract the original value of the current sample from the current reference value to obtain a difference, and the difference is used to determine whether there is a touch on the touch screen. The judging unit 5 judges whether there is a touch on the touch screen by judging whether the difference is smaller than the set second threshold, and if the difference is smaller than the set second threshold, it is determined that there is no touch, otherwise, it is determined that there is a touch.

 The calculation unit 2 is further configured to compare the reference feature value with the backup feature value and take an absolute value to find the maximum value among the absolute values. The determining unit 5 is further configured to determine, when the maximum value of the absolute values of the differences between the current feature value and the backup feature value is less than the maximum value of the absolute values of the difference between the reference feature value and the backup feature value, Whether the absolute value of the difference is greater than the set third threshold, if the absolute value of the difference is greater than the set third threshold, replacing the current sampled original value with the current reference value to update the reference, and determining the current touch For false alarm points, no touch operation is performed.

 The feature value may be a difference value between the original values of the adjacent sampling point samples of the touch screen, a ratio between the original values of the adjacent sampling points of the touch screen, or an original value sampled by each sampling point of the touch screen. When the feature value is a proportional value between the original values sampled by adjacent sampling points of the touch screen, the scale value is a ratio between the original values of adjacent sample points sampled by a set multiple.

The differential value can be backed up in a non-volatile memory of the touch control chip, such as Flash Memory, PROM, EAROM, EPROM or EEPROM, etc., in this embodiment, the differential value backup Stored in the Flash Memory of the touch control chip.

 In this embodiment, by comparing the feature values in the steady state of the touch screen, the sampled values are compared with the backup feature values to determine the correctness of the reference, so that the touch control chip can quickly and accurately obtain the correct reference value during actual detection. , thus correctly updating the benchmark.

 Example 5

 The embodiment provides a touch terminal, and the touch terminal includes a reference update system of the touch screen provided in Embodiment 4.

 In this embodiment, by comparing the feature values in the steady state of the touch screen, the sampled values are compared with the backup feature values to determine the correctness of the reference, so that the touch control chip can quickly and accurately obtain the correct reference value during actual detection. Therefore, the reference is correctly updated, so that the touch terminal has high touch accuracy and a good user experience.

 The above is only the preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. Within the scope.

Claims

claims 1. A touch screen benchmark update method, characterized in that the method includes the following steps: sampling each sampling point when the touch screen is in a stable state, obtaining the original value of the steady state sample, and based on the original value of the steady state sample Calculate the characteristic values of each sampling point of the touch screen and back them up to obtain the backup characteristic values; The touch screen is powered on, and each sampling point is sampled to obtain the original value of the power-on sample. The original value of the power-on sample is used as a reference value to establish a benchmark, and each point of the touch screen is calculated based on the original value of the power-on sample. Power-on characteristic value of the sampling point; Difference the power-on characteristic value and the backup characteristic value and take the absolute value to find the maximum value among the absolute values; Determine whether the maximum value is greater than the set first threshold. If the maximum value is greater than the set first threshold, it is determined that the current benchmark is incorrect; If the current baseline is incorrect, determine whether there is a touch on the touch screen. If there is no touch, update the baseline regularly. If there is a touch, monitor the changes in the original value of the current sample in real time, and update the baseline when the original value of the current sample meets the baseline update conditions. . 2. The touch screen reference update method according to claim 1, characterized in that the step of determining whether there is a touch on the touch screen is specifically: Sample each sampling point to obtain the original value of the current sample, and subtract the original value of the current sample from the current reference value to obtain the difference; Determine whether the difference is less than a set second threshold; If the difference is less than the set second threshold, it is determined that there is no touch; otherwise, it is determined that there is a touch. 3. The touch screen reference update method according to claim 1, wherein if there is no touch, the step of regularly updating the reference is specifically: If there is no touch, every predetermined time interval passes, the current sampled original value is replaced with the current baseline value to update the baseline. 4. The touch screen benchmark update method according to claim 1, characterized in that the real-time monitoring of changes in the original value of the current sample is updated when the original value of the current sample meets the benchmark update conditions. The benchmark steps are as follows: Sampling each sampling point to obtain the original value of the current sampling, calculating the current characteristic value of each sampling point of the touch screen based on the original value of the current sampling, and calculating the reference characteristics of each sampling point of the touch screen based on the current reference value value Difference the current feature value and the backup feature value and take the absolute value, find the maximum value among the absolute values, and obtain the first maximum value; Make the difference between the reference feature value and the backup feature value and take the absolute value , find the maximum value among the absolute values, and obtain the second maximum value; When the first maximum value is less than the second maximum value, determine whether the absolute value of the difference between the second maximum value and the first maximum value is greater than the set third threshold. If the absolute value of the difference is greater than If the third threshold is set, the current sampled original value is replaced with the current baseline value to update the baseline, and the current touch is determined to be a false alarm point, and no touch operation is performed. 5. The reference update method of the touch screen according to claim 1, wherein the characteristic value is the difference value between the original values sampled at adjacent sampling points on the touch screen, and the difference between the original values sampled at adjacent sampling points on the touch screen. The proportional value or the original value sampled at each sampling point of the touch screen. 6. The reference update method of the touch screen according to claim 5, characterized in that, when the characteristic value is a ratio value between the original values sampled at adjacent sampling points on the touch screen, the ratio value is an amplification setting. The ratio between multiples of the original values sampled at adjacent sampling points. 7. The touch screen reference update method according to any one of claims 1 to 6, characterized in that the backup characteristic value is stored in a non-volatile memory. 8. A touch screen benchmark update system, characterized by including: The sampling unit is used to sample each sampling point and obtain the original value of the sample; The calculation unit is used to calculate the characteristic value of each sampling point of the touch screen based on the original value sampled in the steady state, and calculate the current characteristic value of each sampling point of the touch screen based on the original value sampled at each time point when the touch screen is powered on and after powering on, and Difference the current feature value and the backup feature value and take the absolute value to find the maximum value among the absolute values; The backup unit is used to back up the characteristic values in the stable state to obtain the backup characteristic values; The base value establishment unit is used to use the original value sampled when the touch screen is powered on as the base value to establish the base value. allow; Determination unit, used to determine whether the maximum value calculated based on the sampling when the touch screen is powered on is greater than the set first threshold. If the maximum value is greater than the set first threshold, it is determined that the current benchmark is incorrect, and in the current Determine whether there is a touch on the touch screen when the reference is incorrect; A reference value update unit, used to regularly update the reference when the current reference is incorrect and there is no touch on the touch screen, and to update the reference when the current reference is incorrect, there is a touch on the touch screen and the currently sampled original value meets the reference update conditions; The monitoring unit is used to monitor changes in the original value of the current sample in real time when the current reference is incorrect and there is a touch on the touch screen. 9. The touch screen reference update system according to claim 8, characterized in that the calculation unit is also used to subtract the current sampled original value from the current reference value to obtain a difference, and the difference is used to determine the touch screen. whether there is touch; The determination unit determines whether there is a touch on the touch screen by determining whether the difference is less than a set second threshold. If the difference is less than the set second threshold, it is determined that there is no touch. Otherwise, it is determined that there is a touch. touch. 10. The touch screen reference update system according to claim 8, characterized in that the calculation unit is also used to make a difference between the reference feature value and the backup feature value and take the absolute value to find the maximum of the absolute values. value; The determination unit is also configured to determine the two maximum values when the maximum value of the absolute values of the difference between the current feature value and the backup feature value is less than the maximum value of the absolute value of the difference between the reference feature value and the backup feature value. Is the absolute value of the difference greater than the set third threshold? If the absolute value of the difference is greater than the set third threshold, replace the current baseline value with the current sampled original value to update the baseline, and determine the current The touch is a false alarm point and no touch operation is performed. 11. The reference update system of the touch screen according to claim 8, wherein the characteristic value is the difference value between the original values sampled at adjacent sampling points on the touch screen, and the difference between the original values sampled at adjacent sampling points on the touch screen. The proportional value or the original value sampled at each sampling point of the touch screen. 12. The touch screen reference update system according to claim 11, characterized in that when the When the characteristic value is the ratio between the original values sampled at adjacent sampling points on the touch screen, the ratio value is the ratio between the original values sampled at adjacent sampling points amplified by a set multiple. 13. The touch screen reference update system according to any one of claims 8 to 12, characterized in that the backup characteristic value is backed up and stored in a non-volatile memory. 14. A touch terminal, characterized in that the touch terminal includes the touch screen reference update system described in any one of claims 8 to 13.