JP2019145066A - Position detection circuit and position detection method - Google Patents

Abstract

To provide a position detection circuit and position detection method, which allow for determining anomalies of line electrodes through a simple method without displaying a special inspection pattern.SOLUTION: A position detection circuit 18 is configured to: acquire detection values pertaining to capacitance at cross-points between line electrodes 16x, 16y in association with positions of the cross-points; count cross-points with detection values less than a first threshold for each line electrode 16x, 16y; and determine line electrodes 16x, 16y with counted cross-points numbering more than a second threshold to be abnormal or candidate abnormal line electrodes.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a position detection circuit and a position detection method.

  Patent Document 1 discloses a method for displaying an inspection pattern indicating a guidance route for a touch operation, and determining the presence or absence of an abnormality of the touch sensor according to a locus of a detection position formed in accordance with the inspector's touch operation. It is disclosed.

JP 2014-215843 A

  However, the method disclosed in Patent Document 1 has a problem in that it cannot be used in a normal use state because an inspection pattern needs to be displayed in advance.

  An object of the present invention is to provide a position detection circuit and a position detection method capable of determining an abnormal state of a line electrode by a simple method without displaying a special inspection pattern.

  The position detection circuit according to the first aspect of the present invention is a circuit connected to a capacitive touch sensor in which a plurality of line electrodes are arranged in a two-dimensional lattice, and is a static circuit at a cross point between line electrodes. An acquisition step of acquiring a detection value related to electric capacity in association with the position of the cross point, a counting step of counting the number of cross points where the detection value is less than a first threshold for each line electrode, and the counted cross points And a determination step of determining that the line electrode whose number exceeds the second threshold value is abnormal or an abnormal candidate.

  The position detection method according to the second aspect of the present invention is a method using a capacitive touch sensor in which a plurality of line electrodes are arranged in a two-dimensional lattice pattern, and includes electrostatic at cross points between line electrodes. An acquisition step of acquiring a detection value related to capacitance in association with the position of the cross point; a counting step of counting the number of cross points where the detection value is less than a first threshold value for each line electrode; and One or more processors execute a determination step of determining that the number of line electrodes whose number exceeds the second threshold value is abnormal or an abnormal candidate.

  According to the present invention, the abnormal state of the line electrode can be determined by a simple method without displaying a special inspection pattern.

It is a schematic block diagram of the electronic device with which the position detection circuit in one Embodiment of this invention was integrated. It is a flowchart which shows the whole operation | movement of the position detection method by the position detection circuit of FIG. It is a detailed flowchart of the disconnection detection process performed in step S10 of FIG. It is a figure which shows the 1st example of the result obtained by a temporary determination process. It is a figure which shows the 2nd example of the result obtained by a temporary determination process. It is a figure which shows an example of the result obtained by majority processing. 7A, 7B, and 7C are diagrams illustrating examples of signal level distribution in each row line. FIG. 8A is a diagram illustrating an example of an interpolation result by cubic spline interpolation. FIG. 8B is a diagram schematically illustrating the locus of pen coordinates accompanying the movement of the electronic pen. It is a detailed flowchart of the pen coordinate derivation process by the skip continuous line data performed in step S20 of FIG. It is a figure which shows the relationship of the value of the signal level obtained by the skip continuous line data acquisition process. FIG. 11A and FIG. 11B are diagrams illustrating examples of signal level distribution in each row line. FIG. 12A is a diagram illustrating an example of an interpolation result by cubic spline interpolation. FIG. 12B is a diagram schematically showing a locus of pen coordinates accompanying the movement of the electronic pen. It is a flowchart of the correction | amendment switching process according to the skip of a disconnection location. 14A and 14B are diagrams illustrating an example of a pen coordinate correction method.

  A position detection circuit and a position detection method according to the present invention will be described with reference to the accompanying drawings. In addition, this invention is not limited to the following embodiment and modification, Of course, it can change freely in the range which does not deviate from the main point of this invention. Or you may combine each structure arbitrarily in the range which does not produce technical contradiction.

[Configuration of Electronic Device 10]
FIG. 1 is a schematic block diagram of an electronic device 10 incorporating a position detection circuit 18 according to an embodiment of the present invention. The electronic device 10 is configured by, for example, a tablet terminal, a smartphone, or a personal computer. The user can write a picture or character on the electronic device 10 by holding the electronic pen 12 (or stylus) with one hand and moving the pen while pressing the pen tip against the touch surface of a display panel (not shown). Alternatively, the user can perform a desired operation through the user control being displayed by touching the touch surface with his / her finger 14.

  The electronic device 10 includes a touch sensor 16, a position detection circuit 18, and a host processor 20. In addition, the x direction and the y direction shown in this figure correspond to the X axis and the Y axis of the orthogonal coordinate system defined on the plane formed by the touch sensor 16.

  The touch sensor 16 is a plurality of electrodes arranged on the display panel. The touch sensor 16 includes a plurality of line electrodes 16x for detecting the X coordinate (position in the x direction) and a plurality of line electrodes 16y for detecting the Y coordinate (position in the y direction). The plurality of line electrodes 16x are provided to extend in the y direction, and are arranged at equal intervals along the x direction. The plurality of line electrodes 16y are provided so as to extend in the x direction and are arranged at equal intervals along the y direction. Hereinafter, the arrangement interval of the line electrodes 16x (16y) may be referred to as “pitch”.

  The position detection circuit 18 is an integrated circuit configured to be able to execute the firmware 22, and is connected to a plurality of electrodes constituting the touch sensor 16. The firmware 22 is configured to be capable of realizing a touch detection function 24t that detects a touch with the user's finger 14 and the like, and a pen detection function 24p that detects the state of the electronic pen 12.

  The touch detection function 24t includes, for example, a two-dimensional scanning function of the touch sensor 16, a function of creating a heat map (two-dimensional position distribution of detection levels) on the touch sensor 16, and a region classification function (for example, a finger, a palm) Classification). The pen detection function 24p includes, for example, a two-dimensional scan function of the touch sensor 16, a downlink signal reception / analysis function, an estimation function of the state (for example, position, posture, writing pressure) of the electronic pen 12, and a command to the electronic pen 12. Including uplink signal generation / transmission function.

  The host processor 20 is a processor composed of a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The host processor 20 reads out and executes a program from a memory (not shown), for example, a process for generating digital ink using data from the position detection circuit 18, and a visualization process for displaying the drawing content indicated by the digital ink And so on.

[Schematic Operation of Position Detection Circuit 18]
When the touch sensor 16 includes N rows of line electrodes 16x and M columns of line electrodes 16y, there are N × M intersection positions (hereinafter referred to as cross points). In the following description, “row line” means an electrode in the row direction, “column line” means an electrode in the column direction, and “line” means an electrode in either the row direction or the column direction or both.

  The position detection circuit 18 detects the position of the finger 14 by capturing a change in capacitance at each cross point. The position detection circuit 18 detects the state of the electronic pen 12 based on the signal level from the electronic pen 12 detected in the direction of each of the line electrodes 16x and 16y. Note that the detected value related to the capacitance may be a mutual capacitance or a self-capacitance.

  FIG. 2 is a flowchart showing the overall operation of the position detection method by the position detection circuit 18 of FIG. First, the position detection circuit 18 performs a disconnection detection process (step S10). When the disconnection is not detected (S12; NO), the position detection circuit 18 executes a pen coordinate derivation process using all line data. On the other hand, when a disconnection is detected (S12; YES), the position detection circuit 18 executes a pen coordinate derivation process (step S20) using skip continuous line data. This operation may be executed by one processor (position detection circuit 18), or may be executed in cooperation by a plurality of processors.

[Explanation of disconnection detection processing]
<Specific operation>
FIG. 3 is a detailed flowchart of the disconnection detection process executed in step S10 of FIG.

  First, in step S11, a capacitance data table C including capacitance values at N × M cross points is acquired. The capacity data table C is a table of values as shown in FIG.

  Next, in step S12, the abnormal point number EPC for each line in the i-th row line is detected. This detection is performed by, for example, comparing the capacitance values at M cross points included in the i-th row line with a predetermined threshold th1 (first threshold), and the number of abnormal points exceeding the threshold th1. May be counted. Further, this comparison may be a comparison between the difference value between the current row line and the capacitance value in the adjacent row line (for example, the (i−1) -th row line) and the threshold value th1. It may be a comparison with the reference value at the cross point obtained in (1). By this comparison, the number of abnormal points per line EPC (i), which is the number of cross-points determined as abnormal values, is counted (step S123).

  Next, in step S13, it is temporarily determined whether or not the i-th row line is disconnected. First, in step S131, it is determined whether or not the number of abnormal points per line EPC (i) is smaller than a predetermined number th2. If the number is small (S131; YES), it indicates that the i-th row line is not broken. The value is set to the value of the disconnection candidate flag E_Flag for that row (step S133). If the number is large as a result of the determination (S131; NO), a value indicating that the i-th row line is a disconnection candidate is set as the value of the disconnection candidate flag E_Flag (step S135). Further, in this case, the number of abnormal candidate lines ELC for the entire N rows is incremented (step S136).

  4 and 5 are diagrams each illustrating an example of a result obtained by the provisional determination process. Specifically, in the touch panel having X0 to X14 row lines and Y0 to Y14 column lines, examples of the capacitance values acquired at each cross point and the number of abnormal points per line acquired in the above steps Examples of values of EPC, abnormal candidate line number ELC, and disconnection candidate flag E_Flag are shown. When the capacitance value is smaller than 19 (second threshold value), it is determined as an abnormal value.

  In the example of FIG. 4, the Y8 row line having 15 points determined to be abnormal values is provisionally determined as an abnormal candidate line. Further, the number of abnormal candidate lines ELC in the row direction is provisionally determined to be one. In the example of FIG. 5, Y8 to Y10 in which the number of points provisionally determined to be abnormal values is 15 are temporarily determined as abnormality candidate lines. Further, the number of abnormal candidate lines ELC in the row direction is provisionally determined to be three, and the number of abnormal candidate lines ELC in the column direction is provisionally determined to be one.

  Returning to FIG. In step S14, a majority process is performed to determine whether or not the temporarily determined abnormality candidate line is abnormal. First, it is determined whether or not the number of abnormal candidate lines ELC is less than a majority of the number of row lines N (or the number of column lines M) (step S141). As a result of the determination, if the number of abnormal candidate lines ELC is smaller than the majority (S141; YES), the abnormal candidate lines are determined as abnormal lines as they are. As a result of the determination, if the number of abnormal candidate lines ELC is larger than the majority (S141; NO), the abnormal candidate lines (9 lines Y3 to Y11 in the example of FIG. 6) are determined as normal lines and temporarily determined as normal lines. The existing lines (6 lines Y0 to Y2 and Y12 to 14) are determined as abnormal lines. In this process, for example, by inverting the value of the disconnection candidate flag E_Flag for a line temporarily determined to be an abnormal line, the line temporarily determined to be abnormal and the line temporarily determined to be normal can be switched. Then, based on the determined abnormal line, a pen coordinate derivation process in step S20 described later is executed.

  FIG. 6 is a diagram illustrating an example of a result obtained by the majority process. The row lines Y3 to Y11 are temporarily determined as abnormal candidate lines, but the value 9 of the number of abnormal candidate lines occupies a majority of 15 which is the total number of row lines. Such a state is the possibility that the mechanical state of the touch sensor 16 as a whole has changed, or a line temporarily determined as an abnormal candidate when a difference value between adjacent lines is used as a capacitance value. It is difficult to distinguish which side of the group and the non-line group shows normal values. Even in such a situation, in order to continue the detection operation without stopping the touch detection operation, the output of the line group of the row lines Y3 to Y11 temporarily determined as an abnormal candidate line is used, and Y0 The six lines Y2 to Y14 and Y12 to Y14 are replaced with each other on the assumption that the line group is disconnected.

<Effect of disconnection detection processing>
As described above, the position detection circuit 18 is a circuit connected to the capacitive touch sensor 16 in which a plurality of line electrodes 16x and 16y are arranged in a two-dimensional lattice, and the line electrode 16x , 16y, an acquisition step (S11) for acquiring a detection value relating to the capacitance at the cross point in association with the position of the cross point, and the number of cross points where the detection value is lower than the first threshold value as the line electrodes 16x, 16y. A counting step (S12) for counting each time and a determination step (S13, S14) for determining that the line electrodes 16x and 16y in which the number of counted cross points exceeds the second threshold are abnormal or abnormal candidates are executed.

  As described above, the line electrodes 16x and 16y that are abnormal or abnormal candidates are specified by executing the combination of the counting process and the threshold process on the detection value for each cross point that can be acquired in the normal use state. . Thereby, the abnormal state of the line electrodes 16x and 16y can be determined by a simple method without displaying a special inspection pattern.

  In the determination step (S14), the line electrode 16x (16y) constituting one direction of the two-dimensional lattice is used as a population, and the number of line electrodes 16x (16y) that are not abnormal candidates is the total number of samples in the population. When the majority is occupied, it is determined that the line electrode 16x (16y) extracted as the abnormality candidate is abnormal, and the number of the line electrodes 16x (16y) that are abnormality candidates is the majority of the total number of samples in the population. When occupied, it may be determined that the remaining line electrodes 16x (16y) that have not been extracted as abnormality candidates are abnormal. By performing the secondary determination based on the principle of majority decision, the possibility of obtaining an appropriate determination result for the entire population increases.

[Description of pen coordinate derivation process]
<Problems caused by disconnection>
Next, the pen coordinate derivation process will be described. The pen coordinate derivation process is a process of deriving a two-dimensional position in the row direction and the column direction by detecting the pen signal transmitted from the electronic pen 12 with the line electrodes 16x and 16y. In the following, the position detection in the row direction will be described by taking as an example a state in which the electronic pen 12 is located in the vicinity of Y8 among the row lines Y0 to Y15. Hereinafter, processing in the row direction will be described, but it goes without saying that the same processing can be performed in the column direction.

  7A, 7B, and 7C are diagrams illustrating examples of signal level distribution in each row line. FIG. 7A is a diagram illustrating an example of signal level distribution in each row line when no disconnection is detected in any of the row lines Y0 to Y15 (S12 in FIG. 2; NO).

  The signal level detected in each line has a peak value at Y8, Y9 second, and Y7 third. In the pen coordinate derivation process, desired approximation or interpolation is performed using the distribution of the Y7 and Y9 signal levels around the position of Y8 having the peak value as described above, and based on the obtained distribution (curve or curved surface). The maximum coordinate of the signal level is derived and output as the Y coordinate position of the pen near Y8. As the approximation or interpolation algorithm, various methods including, for example, a cubic spline function and a B-spline function are used.

  FIGS. 7B and 7C are distribution diagrams illustrating examples of signal level distributions detected in each row line when Y8 is disconnected in a state where the electronic pen 12 exists at the position Y8. Since Y8 is disconnected, the signal level detected at one of Y9 or Y7 has a peak value, and the signal level detected at the other is the second peak.

  FIG. 8A is a diagram illustrating an example of an interpolation result by cubic spline interpolation. Since the signal level of Y8 is missing, the density (spatial resolution) of data points between Y7 and Y9 is relatively “sparse”. For this reason, when the signal levels of Y7 and Y9 completely match, Y8 becomes the maximum position of the interpolation curve. However, if there is a difference between the two signal levels, the maximum position of the interpolation curve is either Y7 or Y9. There is a tendency to approach one side (the side with a relatively high signal level). That is, the maximum position can vary greatly within the range of Y7 to Y9 (2 pitches).

  As a result, in the example of FIG. 7B, the electronic pen 12 actually exists at the Y8 position, but the position of the electronic pen 12 near the position P9 (black circle position) of the peak value Y9 among the acquired signal levels. Are output as coordinates (hereinafter also referred to as “pen coordinates”). In the example of FIG. 7C, the vicinity of the position P7 (white circle position) of Y7 is output as pen coordinates. 7B and 7C, the signal levels detected by Y7 and Y9 are not so different. This is because both are positions different from the original peak value position. In such a case, the magnitude of the signal level detected at Y7 and the level of the signal detected at Y9 may easily change due to tilting of the electronic pen 12 or camera shake in the row direction, and the like.

  FIG. 8B is a diagram schematically illustrating the locus of pen coordinates accompanying the movement of the electronic pen 12. Here, it is assumed that the pen is moved along the direction in which the disconnected row line Y8 extends. If the magnitude relationship of the signal level is switched for the reason described above, the pen coordinate is initially near the position of P7 (white circle), but then near the position of P9 (black circle), and again returns to the vicinity of the position of P7. It swings with the swing width W1. Here, for example, even if a temporary signal level value (for example, an average value of signal levels acquired at Y7 and Y9) is given to the position of Y8, this problem still remains. In particular, when a plurality of continuous lines are disconnected at the same time, the deflection width W1 is further increased.

<Specific operation>
FIG. 9 is a detailed flowchart of the pen coordinate derivation process using skip continuous line data executed in step S20 of FIG.

  First, a connection relationship changing process is executed (step S210). Here, the connection relationship means a correspondence relationship between the actual position and the original data position. This change process is a process of rearranging data so that the signal level value acquired in each row line Y0 to Y14 skips the disconnection position and is adjacent to each other. That is, this change process corresponds to a skip continuous line data acquisition process for acquiring skip continuous line data.

  FIG. 10 is a diagram illustrating the relationship between the signal level values obtained by the skip continuous line data acquisition process. For example, if it is determined that the Y8 row line is disconnected, the reading of data at the Y8 address position is skipped, and the data address relationship is switched so that the data stored in the next Y9 is read. . That is, this “skip” corresponds to an address conversion process for narrowing the corresponding positions of the line.

  Next, a pen coordinate derivation process is executed using skip continuous line data supplied based on this connection relationship. The pen coordinate derivation process is the same process as the pen coordinate derivation process executed in step S13 in FIG. 2 except that the data is changed. That is, processing is actually performed at the position Y8 using the signal level data acquired at Y9.

  FIG. 11A to FIG. 12B are diagrams for explaining the effect of the position derivation process using this skip continuous line. In the example of FIG. 11A, the vicinity of the position P8 (black square) of the peak value Y8 (actually Y9 data) is output as pen coordinates. In the example of FIG. 11B, the vicinity of the position P7 (white square) of Y7 which is the peak value is output as pen coordinates.

  FIG. 12A is a diagram illustrating an example of an interpolation result by cubic spline interpolation. Since the signal level of Y8 is skipped, the spatial resolution between Y7 and Y8 (actually Y9 data) is equivalent to the case where there is no disconnection. That is, even when a difference occurs between the signal levels of Y7 and Y9, the fluctuation of the maximum position in the interpolation curve can be kept within the range of Y7 to Y8 (one pitch).

  FIG. 12B is a diagram schematically illustrating the locus of pen coordinates accompanying the movement of the electronic pen 12. As in FIG. 8B, it is assumed that the electronic pen 12 is moved along the direction in which the disconnected row line Y8 extends. When the magnitude relationship of the signal level is switched for the above-described reason, the pen coordinate is initially near the position of P7 (white circle), but after that, it is not near P9 but near the position of P8 (black). Therefore, compared with the swing width W1 of FIG. 8B, the swing width W2 can be suppressed by about one pitch, and a state in which the drawn line swings up and down like a barcode can be suppressed. .

  In addition, the pen coordinates obtained from the skip continuous data in this manner are shifted from the break position Y8 as a boundary. In such a case, it may be determined whether the position is before or after the disconnection position, and the correction may be switched between the front and the rear and output.

  FIG. 13 is a flowchart of the correction switching process according to the skip of the disconnection point.

  First, in step S221, it is determined whether or not the output target position is before the disconnection position (whether or not affected). For example, the row lines Y0 to Y7 are determined to be positions before the disconnection position of Y8. If it is before the disconnection position (S221; YES), the derived pen coordinates are output as they are (step S223).

  On the other hand, if it is after the disconnection position (S221; NO), the derived pen coordinates are shifted backward by the shift amount corresponding to the number of disconnections and output (step S223). For example, if one row line is disconnected, pen coordinates shifted backward are output by one pitch and if three row lines are disconnected, three pitches are output. As a result, it is possible to suppress a shift in the detection position due to skipping at a position where there is essentially no influence of disconnection. Note that the pen coordinate correction method may be the above-described position shift (see FIG. 14A) or the range expansion of a predetermined section (Y6 to Y9) (see FIG. 14B).

<Effects of pen coordinate derivation processing>
As described above, the position detection circuit 18 is a circuit connected to the capacitive touch sensor 16 in which a plurality of line electrodes 16x and 16y are arranged in a two-dimensional lattice, and the line electrode 16x , 16y, an acquisition step (S11) for acquiring a detection value relating to the capacitance at the cross point in association with the position of the cross point, and a determination for determining whether the line electrodes 16x, 16y are normal. Step (S14) and a derivation step (S20) for performing approximation or interpolation using a plurality of data points indicating the distribution of detected values and deriving the detected position based on the maximum coordinates of the detected values in the obtained distribution are executed. In the above derivation step, approximation or interpolation is performed by skipping data points corresponding to the line electrodes 16x and 16y determined to be abnormal. Good.

  Since it comprised in this way, the local fall of the spatial resolution resulting from abnormality of the line electrodes 16x and 16y can be suppressed, and the derivation accuracy of the detection position by approximation or interpolation can be maintained. Thereby, when performing a touch operation along a specific direction, fluctuations in the line width direction can be suppressed.

  In the derivation step, the detection position may be derived by correcting the maximal coordinate according to the number of skipped data points. Thereby, the shift | offset | difference of the detection position accompanying a skip can be suppressed.

  In the acquisition step, a detection value related to the capacitance between the electronic pen 12 and the touch sensor 16 capable of writing with a line width narrower than the pitch between the line electrodes 16x (16y) may be acquired. When the electronic pen 12 having a high spatial resolution at the indicated position is used, since the detection accuracy of the pen coordinates is required correspondingly, the above-described fluctuation suppressing effect appears more remarkably.

10 electronic devices, 12 electronic pens, 14 fingers, 16 touch sensors, 16x, 16y line electrodes, 18 position detection circuits, 20 host processors.

Claims (10)

A position detection circuit connected to a capacitive touch sensor in which a plurality of line electrodes are arranged in a two-dimensional grid,
An acquisition step of acquiring a detection value related to capacitance at a cross point between line electrodes in association with a position of the cross point;
A counting step of counting the number of cross points where the detected value is lower than a first threshold for each line electrode;
A determination step for determining that a line electrode in which the number of counted cross points exceeds a second threshold is abnormal or an abnormal candidate;
The position detection circuit characterized by performing. In the determination step,
If the line electrode that constitutes one direction of the two-dimensional lattice is a population, and the number of line electrodes that are not abnormal candidates accounts for a majority of the total number of samples in the population, the line electrode extracted as an abnormal candidate is abnormal. It is determined that
When the number of line electrodes that are abnormal candidates occupies a majority of the total number of samples of the population, it is determined that the remaining line electrodes that are not extracted as abnormal candidates are abnormal. The position detection circuit according to 1. Approximating or interpolating using a plurality of data points indicating the detection value distribution, and further including a derivation step of deriving a detection position based on the maximum coordinates of the detection value in the obtained distribution,
3. The position detection circuit according to claim 1, wherein in the derivation step, approximation or interpolation is performed by skipping data points corresponding to line electrodes determined to be abnormal.   4. The position detection circuit according to claim 3, wherein in the derivation step, the detection position is derived by correcting the local maximum coordinate according to the number of skipped data points.   5. The acquisition step according to claim 3, wherein, in the acquisition step, the detection value regarding the capacitance between the touch pen and the electronic pen capable of writing with a line width narrower than the pitch between the line electrodes is acquired. Position detection circuit. A position detection method using a capacitive touch sensor in which a plurality of line electrodes are arranged in a two-dimensional grid,
An acquisition step of acquiring a detection value related to capacitance at a cross point between line electrodes in association with a position of the cross point;
A counting step of counting the number of cross points where the detected value is lower than a first threshold for each line electrode;
A determination step of determining that a line electrode in which the counted number of cross points exceeds a second threshold is abnormal or an abnormal candidate;
Is executed by one or a plurality of processors. In the determination step,
If the line electrode that constitutes one direction of the two-dimensional lattice is a population, and the number of line electrodes that are not abnormal candidates accounts for a majority of the total number of samples in the population, the line electrode extracted as an abnormal candidate is abnormal. It is determined that
When the number of line electrodes that are abnormal candidates occupies a majority of the total number of samples of the population, it is determined that the remaining line electrodes that are not extracted as abnormal candidates are abnormal. 6. The position detection method according to 6. Approximating or interpolating using a plurality of data points indicating the detection value distribution, and further including a derivation step of deriving a detection position based on the maximum coordinates of the detection value in the obtained distribution,
8. The position detection method according to claim 7, wherein in the derivation step, approximation or interpolation is performed by skipping data points corresponding to line electrodes determined to be abnormal.   9. The position detection method according to claim 8, wherein, in the derivation step, the detection position is derived by correcting the local maximum coordinate according to the number of skipped data points. 10. The acquisition step according to claim 8, wherein, in the acquisition step, the detection value related to a capacitance between the electronic pen capable of writing with a line width narrower than a pitch between line electrodes and the touch sensor is acquired. Position detection method.