A linear degree testing method for a whole machine resistance touch screen
By dividing the entire machine into a grid matrix and using statistical elimination and extreme value evaluation methods for linearity testing, the problem of removing the resistive touchscreen in linearity testing was solved, achieving efficient and accurate linearity evaluation and reducing costs and risks.
Patent Information
- Application Number
- CN202610792435.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-03
- Publication Date
- 2026-08-25
AI Technical Summary
In existing technologies, linearity testers can only test bare resistive touchscreens, which requires the removal of the resistive touchscreen during the debugging and after-sales process, increasing labor and material costs and posing a risk of damage.
By dividing the effective touch area of the resistive touchscreen into an equally divided grid matrix, a two-dimensional coordinate system is constructed to obtain the actual coordinate points. The linearity is calculated using the statistical elimination method and the extreme value evaluation method. The resistive touchscreen can be removed and the test can be performed directly on the whole device.
Testing can be completed without removing the resistive touchscreen, reducing labor and material costs, improving testing efficiency and accuracy, avoiding the risk of component damage, and simplifying testing equipment requirements.
Smart Images
Figure CN122631979A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for testing the linearity of a resistive touchscreen, and more particularly to a method for testing the linearity of a resistive touchscreen on an entire device. Background Technology
[0002] Because of the uneven conductive coating in resistive touchscreens, the electrode design cannot completely guarantee a uniform electric field distribution between the edges and the center. This results in uneven voltage gradients in resistive touchscreens, which disrupts the linear relationship between the actual output voltage and the touch position. Currently, linearity is typically used to quantify the degree of this disruption, i.e., the degree of deviation between the actual output characteristics and the ideal linear characteristics.
[0003] At the circuit level, linearity is the maximum deviation between the actual average output voltage characteristic curve of a resistive touchscreen and the optimal voltage straight line, usually expressed as a percentage of the full-scale output of the resistive touchscreen. At the application level, linearity is the error between the actual touch position and the theoretically calculated position. The two definitions are essentially equivalent. Good linearity ensures that when a user draws a line or clicks on a resistive touchscreen, the trajectory and landing point closely match the actual path, avoiding line distortion or click drift.
[0004] Resistive touchscreen manufacturers typically use a resistive touchscreen linearity tester (referred to as a "line tester") to measure the linearity of the resistive touchscreens at the factory. The line tester uses a computer-controlled high-precision automated stage to perform the linearity test. When using the line tester, the resistive touchscreen must be in a bare screen state and fixed to the designated test area of the line tester.
[0005] Panel manufacturers install resistive touchscreens onto their machines to form complete units. During the overall machine debugging phase or after long-term use by end users, if a significant deviation is found between the touch area and the response area, it may be necessary to investigate whether the resistive touchscreen has excessive linearity. Since line testing machines can only test the bare screen, the resistive touchscreen must be removed from the machine before testing. However, resistive touchscreens are typically installed using adhesive backing, and removal not only requires additional manual labor but also necessitates careful and time-consuming operation to minimize the probability of touchscreen damage, further increasing labor costs. Simultaneously, there is still a risk of touchscreen breakage, damage to the LCD screen, structural components, or other non-testable components during removal, increasing material costs. Furthermore, even if the test is passed, the resistive touchscreen must be reinstalled into the machine, further increasing labor costs and the risk of material damage. Therefore, a linearity testing method that can be directly applied to the entire machine without removing the resistive touchscreen is needed. Summary of the Invention
[0006] This invention aims to solve the problem in existing technologies where line testing machines can only test the bare screen, requiring the removal of the resistive touchscreen for testing during overall machine debugging and after-sales service, resulting in high material and labor costs. It provides a method for testing the linearity of the resistive touchscreen on the entire machine. This method eliminates the need to remove the resistive touchscreen and can be directly applied to the entire machine, saving the trouble of removal and reinstallation. It fundamentally avoids damage to the resistive touchscreen, as well as damage to the LCD screen, structural components, and other non-testable components caused by removal and reinstallation, significantly reducing material and labor costs during overall machine debugging and after-sales testing.
[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for testing the linearity of a resistive touchscreen on a complete machine, comprising the following steps: (1) Divide the effective touch area of the resistive touch screen into an equally divided grid matrix and construct a two-dimensional coordinate system; (2) Obtain the actual coordinates of each grid point and construct the actual coordinate matrix; (3) For each row and column of the actual coordinate matrix, the statistical elimination method is used to process the actual coordinate points respectively, that is, after sorting, the extreme values are removed and the average of the remaining intermediate values is taken to eliminate the influence of sampling outliers on the fitted ideal coordinate values, so as to obtain the fitted ideal coordinate values of each row and column. (4) Combine the fitted ideal coordinate values of each row and each column according to the corresponding row and column to obtain the corresponding fitted ideal coordinate points, and use the fitted ideal coordinate points to construct the fitted ideal coordinate matrix; (5) Using the extreme value evaluation method, calculate the absolute deviation between each actual coordinate point and the corresponding fitted ideal coordinate point, and use the largest absolute deviation as the basis for linearity evaluation; (6) The linearity is obtained based on the maximum absolute deviation and full scale.
[0008] Compared with the prior art, the advantages of the present invention are as follows: (i) Testing can be completed without removing the resistive touchscreen from the entire device. This invention allows for linearity testing of the resistive touchscreen directly in the assembled state of the device, without removing the resistive touchscreen from the device or reinstalling it after the test is passed. This reduces manual operation steps, lowers labor costs, and improves testing efficiency. Furthermore, it fundamentally avoids the risk of damage to the resistive touchscreen, LCD screen, structural components, and other non-test target components caused by removal operations, significantly reducing material costs during device debugging and after-sales testing.
[0009] (ii) The statistical elimination method is used to eliminate outliers in the sampling and improve the accuracy of the test. The present invention uses the statistical elimination method to process the actual coordinate points of each row and each column. After sorting, the extreme values are removed and the average of the remaining intermediate values is taken. This effectively eliminates the influence of outliers in the sampling caused by noise interference, accidental touch or instantaneous fluctuations on the linearity calculation, making the fitted ideal coordinate values more stable and reliable, thereby improving the accuracy of the linearity test.
[0010] (III) Employing the extreme value evaluation method, using the maximum deviation as the evaluation criterion to ensure full-screen coverage. This invention employs the extreme value evaluation method to calculate the absolute deviation between each actual coordinate point and its corresponding fitted ideal coordinate point, and uses the maximum absolute deviation as the linearity evaluation criterion. This method can effectively capture the worst point across the entire screen of the resistive touchscreen, ensuring that the linearity evaluation covers the entire touch area of the resistive touchscreen, avoiding the problem of masking edges or local linearity defects due to local averaging, and providing a more rigorous basis for judging the linearity of resistive touchscreens.
[0011] (iv) The testing method is simple and requires no special testing equipment. This invention only requires clicking the grid points sequentially and collecting the voltage values output by the resistive touch screen interface when the whole machine is powered on. The linearity test can be completed through simple data processing. There is no need to use a special line tester, which lowers the threshold of testing equipment and facilitates its application in production line debugging and after-sales maintenance scenarios.
[0012] In a further technical solution, in step (1), the size of the equally divided grid point matrix is N×M, where N and M are both not less than 15, and the two-dimensional coordinate system uses the long side and the wide side of the effective touch area of the resistive touch screen as the X-axis and Y-axis, respectively; specifically, the X-axis direction is the column distribution direction of the equally divided grid point matrix, and the Y-axis direction is the row distribution direction of the equally divided grid point matrix.
[0013] In a further technical solution, in step (2), the specific way to obtain the actual coordinates of each grid point and construct the actual coordinate matrix is as follows: when the whole machine is powered on, click each grid point in sequence, collect the voltage value output by the resistive touch screen interface, perform analog-to-digital conversion on the voltage value to obtain the actual coordinates of each grid point, and then distribute the actual coordinates of each grid point according to its position in the equally divided grid point matrix to obtain the actual coordinate matrix.
[0014] Specifically, the voltage value output by the resistive touchscreen interface when the grid point in the nth row and mth column is clicked is denoted as (V). Xm V Yn ), where V Xm This represents the voltage value along the X-axis at that grid point, in V. Yn This represents the voltage value along the Y-axis at this grid point, n = 1, 2, ..., N, m = 1, 2, ..., M; V XmThe coordinate values obtained by analog-to-digital conversion are denoted as X. m-n V represents the X-axis coordinate of the nth grid point in the mth column. Yn The coordinate values obtained by analog-to-digital conversion are denoted as Y. n-m , representing the Y-axis coordinate value of the nth grid point in the mth column, (X m-n Y n-m () represents the actual coordinate point located in the nth row and mth column of the actual coordinate matrix.
[0015] In a further technical solution, in step (3), the specific method for processing the N actual coordinate points in the m-th column using a statistical elimination method to obtain their fitted ideal coordinate values is as follows: the X-axis coordinate values (i.e., X...) of the N actual coordinate points in the m-th column are... m-1 X m-2 X m-3 ...X m-N Sort the X-axis coordinates in ascending order, then remove the smallest and largest *a* X-axis coordinate values (where *a* is a preset value), and take the average of the remaining *N-2*a* X-axis coordinate values. Use this average as the ideal fitted coordinate value X for the *m*th column. m .
[0016] Preferably, a is 3-5.
[0017] In a further technical solution, in step (3), the specific method for obtaining the fitted ideal coordinate values of the M actual coordinate points in the nth row by using a statistical elimination method is as follows: the Y-axis coordinate values (i.e., Y...) of the M actual coordinate points in the nth row are... n-1 Y n-2 Y n-3 ...Y n-M Sort the Y-axis coordinates in ascending order, then remove the smallest b Y-axis coordinates and the largest b Y-axis coordinates (where b is a preset value), and take the average of the remaining M-2b Y-axis coordinates. Use this average as the fitted ideal coordinate value Y for the nth row. n .
[0018] Preferably, b is 3-5.
[0019] In a further technical solution, in step (4), the specific method for combining the fitted ideal coordinate values of each row and each column according to the corresponding rows and columns is as follows: the fitted ideal coordinate value Y of the nth row n The ideal coordinates X of the fitted column m m Combining the results, we obtain the ideal fitted coordinates as (X... m Y n ), which is located in the nth row and mth column of the fitted ideal coordinate matrix.
[0020] In a further technical solution, in step (5), the extreme value evaluation method is used to calculate the absolute deviation between each actual coordinate point and the corresponding fitted ideal coordinate point, and the largest absolute deviation is used as the basis for linearity evaluation. The specific method is as follows: Calculate the absolute difference between the X-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its corresponding column, specifically: |X 1-1 - X1|、| X 1-2 - X1|、……、| X 1-N - X1|;| X 2-1 – X2|、| X 2-2 – X2|……| X 2-N – X2|;……;| X M-1 – X M |、| X M-2 – X M |、……、| X M-N – X M |; The largest absolute difference is taken as the maximum absolute deviation on the X-axis, denoted as X. diff-max ; Calculate the absolute difference between the Y-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its row, specifically: |Y 1-1 - Y1|、| Y 1-2 - Y1|、……、| Y 1-M - Y1|; | Y 2-1 –Y2|、| Y 2-2 –Y2|、……、|Y 2-M – Y2|;……; | Y N-1 – Y N |、| Y N-2 – Y N |、……、| Y N-M – Y N The largest absolute difference is taken as the maximum absolute deviation on the Y-axis, denoted as Y. diff-max .
[0021] In a further technical solution, the linearity is obtained based on the maximum absolute deviation and full scale by calculating X using the formula X. diff-max / (X) M - X1) × 100% yields the linearity of the X-axis; Y is calculated using the formula... diff-max / (Y N -Y1)×100% yields the linearity of the Y-axis. The linearity calculations for the X and Y axes are processed separately. Statistical elimination and extreme value evaluation are performed on the X-axis coordinates in the column direction and the Y-axis coordinates in the row direction, respectively. This avoids the increased computational complexity caused by two-dimensional joint processing, reduces the difficulty of algorithm implementation, and improves testing speed.
[0022] In a further technical solution, the resistive touchscreen is a resistive touchscreen that is already installed on the whole machine and does not need to be removed from the whole machine during testing. Attached Figure Description
[0023] Figure 1 This is a flowchart of the linearity test method for resistive touchscreen on the whole machine according to the present invention; Figure 2 This is a schematic diagram of the actual coordinate matrix in a two-dimensional coordinate system in the whole-machine resistive touch screen linearity test method of the present invention. Figure 3 This is a schematic diagram of fitting the ideal coordinate matrix in a two-dimensional coordinate system in the linearity test method of the resistive touch screen on the whole machine of the present invention. Detailed Implementation
[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.
[0025] Example: Figure 1 As shown, a method for testing the linearity of a resistive touchscreen on a complete device is described. The resistive touchscreen is already installed on the device. The method includes the following steps: (1) Divide the effective touch area of the resistive touch screen into an equally divided grid matrix and construct a two-dimensional coordinate system; wherein, the size of the equally divided grid matrix is N×M, and N and M are both equal to 20, and the two-dimensional coordinate system uses the long side and the wide side of the effective touch area of the resistive touch screen as the X-axis and Y-axis respectively; specifically, the X-axis direction is the column distribution direction of the equally divided grid matrix, and the Y-axis direction is the row distribution direction of the equally divided grid matrix; (2) With the entire machine powered on, click each grid point in sequence to collect the voltage value output by the resistive touch screen interface. Convert the voltage value from analog to digital to obtain the actual coordinates of each grid point. Then, distribute the actual coordinates of each grid point according to its position in the equally divided grid point matrix to obtain the actual coordinate matrix. Among them, the voltage value output by the resistive touch screen interface when clicking the grid point in the nth row and mth column is recorded as (V Xm V Yn ), V Xm This represents the voltage value along the X-axis at that grid point, in V. Yn This represents the voltage value along the Y-axis at this grid point, n = 1, 2, ..., N, m = 1, 2, ..., M; V Xm The coordinate values obtained by analog-to-digital conversion are denoted as X. m-n V represents the X-axis coordinate of the nth grid point in the mth column. Yn The coordinate values obtained by analog-to-digital conversion are denoted as Y. n-m , representing the Y-axis coordinate value of the nth grid point in the mth column, (X m-n Y n-m() represents the actual coordinates of the point located in the nth row and mth column of the actual coordinate matrix; The schematic diagram of the distribution of the above actual coordinate matrix in the two-dimensional coordinate system is shown below. Figure 2 As shown; (3) For each row and column of the actual coordinate matrix, the actual coordinate points are processed by statistical elimination method to obtain the fitted ideal coordinate values for each row and column; In this embodiment, the X-axis coordinate values of the N actual coordinate points in the m-th column, i.e., X... m-1 X m-2 X m-3 ...X m-N Sort the values in ascending order, then remove the three smallest and three largest X-axis coordinates, and take the average of the remaining 14 X-axis coordinates. Use this average as the ideal fitted coordinate value X for the m-th column. m Where m = 1, 2, ..., M; In this embodiment, the Y-axis coordinate value of the M actual coordinate points in the nth row, i.e., Y... n-1 Y n-2 Y n-3 ...Y n-M Sort the values in ascending order, then remove the three smallest and three largest Y-axis coordinates, and take the average of the remaining 14 Y-axis coordinates. Use this average as the fitted ideal coordinate value Y for the nth row. n Where n = 1, 2, ..., N; (4) Combine the fitted ideal coordinate values of each row and each column according to the corresponding row and column to obtain the corresponding fitted ideal coordinate points, and construct the fitted ideal coordinate matrix using the fitted ideal coordinate points; where the fitted ideal coordinate value Y in the nth row is... n The ideal coordinates X of the fitted column m m Combining the results, we obtain the ideal fitted coordinates as (X... m Y n ), which is located in the nth row and mth column of the fitted ideal coordinate matrix; The distribution diagram of the above-mentioned fitted ideal coordinate matrix in the two-dimensional coordinate system is shown below. Figure 3 As shown; (5) Calculate the absolute difference between the X-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its column, specifically: |X 1-1 - X1|、| X 1-2 - X1|、……、| X 1-N - X1|;| X 2-1 – X2|、| X 2-2 – X2|……| X 2-N – X2|;……;| X M-1 – XM |、| X M-2 – X M |、……、| X M-N – X M |; The largest absolute difference is taken as the maximum absolute deviation on the X-axis, denoted as X. diff-max ; Calculate the absolute difference between the Y-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its row, specifically: |Y 1-1 - Y1|、| Y 1-2 - Y1|、……、| Y 1-M - Y1|; | Y 2-1 –Y2|、| Y 2-2 –Y2|、……、|Y 2-M – Y2|;……; | Y N-1 – Y N |、| Y N-2 – Y N |、……、| Y N-M – Y N |; The largest absolute difference is taken as the maximum absolute deviation on the Y-axis, denoted as Y. diff-max ; (6) Calculate X using formula diff-max / (X) M - X1) × 100% yields the linearity of the X-axis; Y is calculated using the formula... diff-max / (Y N - Y1)×100% yields the linearity of the Y-axis; thus, the linearity calculations of the X-axis and Y-axis directions are processed separately, and statistical elimination and extreme value evaluation are performed on the X-axis coordinates in the column direction and the Y-axis coordinates in the row direction respectively, avoiding the increase in computational complexity caused by two-dimensional joint processing.
[0026] To verify the performance of the present invention, the testing method of this embodiment was used to conduct experimental tests on the entire device. The device uses a G15FH6-TR panel, which is a resistive touchscreen of model STW-151051.
[0027] Ten G15FH6-TR panels with significant touch deviations were selected as the test units, numbered 1-10. The linearity of the resistive touchscreen in the X and Y axes was first tested directly on each unit using the testing method described in this embodiment. After testing, the resistive touchscreens were removed from the ten units, and their linearity in the X and Y axes was retested using a line tester. The test data are shown in Table 1.
[0028] Table 1: Linearity data of resistive touchscreens in 10 devices with severe touch deviation
[0029] Analysis of the data in Table 1 shows that: (1) Using the testing method of this embodiment, the linearity of the resistive touchscreen was tested on 10 complete machines with serious touch deviations. The linearity of the X-axis of machine number 2 did not meet the maximum linearity requirement of 2%, the linearity of both the X-axis and Y-axis of machine number 5 did not meet the maximum linearity requirement of 2%, the linearity of the X-axis of machine number 7 did not meet the maximum linearity requirement of 2%, and the linearity of the Y-axis of machine number 10 did not meet the maximum linearity requirement of 2%. Only when the linearity of both the X-axis and Y-axis directions simultaneously meets the maximum linearity requirement of 2% is the linearity of the resistive touchscreen considered qualified. Based on the above test results, it can be preliminarily concluded that the linearity of machines numbered 2, 5, 7, and 10 is unqualified, while the linearity of the other machines is qualified.
[0030] (2) After removing the resistive touchscreens from the 10 units with severe touch deviations, the linearity of the resistive touchscreens was retested using a line tester. The measured linearity data of the resistive touchscreens was basically consistent with the linearity data of the resistive touchscreens measured using the test method of this embodiment. It should be noted that the removal operation was performed by experienced personnel, but during the removal operation, the resistive touchscreens of units numbered 7 and 9 were still damaged and could not be used for subsequent testing.
[0031] The above experimental data shows that the test results of directly testing the linearity of the resistive touchscreen on the entire device using the present invention are basically consistent with the test results of the line tester on the bare screen. The present invention has a test accuracy comparable to that of the line tester. Therefore, the present invention eliminates the need to remove the resistive touchscreen from the entire device, achieving online testing of the linearity of the resistive touchscreen during device debugging and after-sales service while ensuring test accuracy.
Claims
1. A method for testing the linearity of a resistive touchscreen on a complete machine, characterized in that, Includes the following steps: (1) Divide the effective touch area of the resistive touch screen into an equally divided grid matrix and construct a two-dimensional coordinate system; (2) Obtain the actual coordinates of each grid point and construct the actual coordinate matrix; (3) For each row and each column of the actual coordinate matrix, the actual coordinate points are processed by statistical elimination method to obtain the fitted ideal coordinate values for each row and each column; (4) Combine the fitted ideal coordinate values of each row and each column according to the corresponding row and column to obtain the corresponding fitted ideal coordinate points, and use the fitted ideal coordinate points to construct the fitted ideal coordinate matrix; (5) Using the extreme value evaluation method, calculate the absolute deviation between each actual coordinate point and the corresponding fitted ideal coordinate point, and use the largest absolute deviation as the basis for linearity evaluation; (6) The linearity is obtained based on the maximum absolute deviation and full scale.
2. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 1, characterized in that, In step (1), the size of the equally divided grid matrix is N×M, where N and M are both not less than 15, and the two-dimensional coordinate system uses the long side and the wide side of the effective touch area of the resistive touch screen as the X-axis and Y-axis, respectively.
3. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 1 or 2, characterized in that, In step (2), the specific method for obtaining the actual coordinates of each grid point and constructing the actual coordinate matrix is as follows: when the whole machine is powered on, click each grid point in sequence, collect the voltage value output by the resistive touch screen interface, perform analog-to-digital conversion on the voltage value to obtain the actual coordinates of each grid point, and then distribute the actual coordinates of each grid point according to its position in the equally divided grid point matrix to obtain the actual coordinate matrix.
4. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 2, characterized in that, In step (3), the specific method for obtaining the fitted ideal coordinate values of the N actual coordinate points in the m-th column by statistical elimination is as follows: sort the X-axis coordinate values of the N actual coordinate points in the m-th column from smallest to largest, then remove the smallest a X-axis coordinate values and the largest a X-axis coordinate values, where a is a preset value, and take the average of the remaining N-2a X-axis coordinate values as the fitted ideal coordinate value X of the m-th column. m Where m = 1, 2, ..., M.
5. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 4, characterized in that, In step (3), the specific method for obtaining the fitted ideal coordinate values of the M actual coordinate points in the nth row by statistical elimination is as follows: sort the Y-axis coordinate values of the M actual coordinate points in the nth row in ascending order, then remove the smallest b Y-axis coordinate values and the largest b Y-axis coordinate values, where b is a preset value, and take the average of the remaining M-2b Y-axis coordinate values. Use this average value as the fitted ideal coordinate value Y of the nth row. n Where n = 1, 2, ..., N.
6. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 2, characterized in that, In step (4), the specific method for combining the fitted ideal coordinate values of each row and each column according to the corresponding rows and columns is as follows: the fitted ideal coordinate value Y of the nth row n The ideal coordinates X of the fitted column m m Combining the results, we obtain the ideal fitted coordinates as (X... m Y n ), which is located in the nth row and mth column of the fitted ideal coordinate matrix.
7. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 6, characterized in that, In step (5), the extreme value evaluation method is used to calculate the absolute deviation between each actual coordinate point and the corresponding fitted ideal coordinate point, and the largest absolute deviation is used as the basis for linearity evaluation. The specific method is as follows: calculate the absolute difference between the X-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its column, and take the largest absolute difference as the maximum absolute deviation of the X-axis, denoted as X. diff-max Calculate the absolute difference between the Y-axis coordinate value of each actual coordinate point and the fitted ideal coordinate value of its row. The largest absolute difference is taken as the maximum absolute deviation of the Y-axis, denoted as Y. diff-max .
8. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 7, characterized in that, The specific method for obtaining linearity based on the maximum absolute deviation and full scale is as follows: using the formula X... diff-max / (X) M - X1) × 100% yields the linearity of the X-axis; Y is calculated using the formula... diff-max / (Y N -Y1)×100% yields the linearity of the Y-axis.
9. The method for testing the linearity of a resistive touchscreen on a complete machine according to claim 1, characterized in that, The resistive touchscreen is a resistive touchscreen that is already installed on the device and does not need to be removed from the device during testing.