JP2015194793A - Evaluation method for coordinates input system and/or program for having computer execute evaluation method for the same and/or computer readable recording medium storing the program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaluation and inspection method for detecting local distortion while suppressing the number of input of straight lines to be as few as possible by evaluating a series of straight line property which is the result of detection and calculation result of the inputted straight line.SOLUTION: An evaluation method detects and outputs a position indicated by a coordinate indicator such as a finger or a pen and detects local abnormality in resistance value in a surface resistor composing a coordinate input range in a coordinate input system and an evaluation method for the coordinates input system: inputs a plurality of straight lines at a prescribed interval in two directions orthogonal to each other by the coordinate indicator inside a coordinate input range; determines whether a local resistance abnormality exists of a size greater than a first threshold to a group of output coordinates in the coordinate input system corresponding to the straight line; having a plurality of local curves be a cluster of curves group when at least a plurality of local curves exist in a specified range and determines that a local resistance value abnormality exists in the surface resistor in the range.

Description

  The present invention relates to a coordinate input system or a coordinate input panel for detecting a position touched by a finger or a coordinate indicator, and mainly to an evaluation / inspection method of a surface type or resistive film type product in an electrostatic coupling method.

  First, a surface-type electrostatic coupling type coordinate input system will be described. FIG. 8 shows a coordinate input panel 1 having a rectangular coordinate input area 8, and a resistive surrounding surrounding the surface resistor 2 so as to be electrically connected to the surface resistor 2. An electrode 3 is disposed, and detection electrodes 4, 5, 6, and 7 are provided at four vertices. The detection electrodes 4, 5, 6, and 7 are electrically connected to the resistive surrounding electrode 3. The coordinate input area 8 is on the surface resistor 2 and inside the resistive surrounding electrode 3.

  As a coordinate detection method of the coordinate input system using the coordinate input panel 1, a signal is transmitted from a coordinate indicator (hereinafter referred to as an input pen) such that the coordinate input panel 1 is a receiving side, and capacitive coupling or A method in which the surface resistor 2 receives a signal transmitted from the input pen through direct contact, and furthermore, the position of the point indicated by a finger or a conductor is input by oscillating the entire surface resistor 2 with voltage. A method of detecting on the panel side, and a method of receiving the signal with the input pen by signal driving each part of the surface resistor 2 when the direction of signal transmission is the opposite, the coordinate input panel 1 is the transmission side is there.

  When the coordinate input panel 1 is the receiving side, it is known to measure the current value distributed to the four vertices (4, 5, 6, and 7) of the current that enters and exits one point of the surface resistor 2. (See Japanese Patent No. 3237629 (Patent Document 1)). On the other hand, when the coordinate input panel 1 is the transmission side, a potential gradient is applied from the outside by connecting the detection electrodes 4, 5, 6, and 7 to the surface resistor 2 by distributing them to a constant potential or ground. A device that detects the voltage level of a designated coordinate point with a pen is known. As the coordinates of the position in the coordinate input area 8 designated by the finger or the input pen, the distribution value of the current flowing in and out of the surface resistor 2 to the four vertices or the voltage measured by the input pen when the four vertices are driven is used. Is calculated.

  As a method of allocating current to the four vertices or driving the four vertices, a method is known in which current is distributed to all four vertices or all four vertices are distributed to either a constant potential or ground. . Also, the four vertices are divided into two pairs with two at the diagonal as one set, and the two sets are alternately selected to distribute the current to the two vertices of the diagonal, or the two sets are alternately A diagonal method is known in which two vertices of these diagonals are selected and connected to a constant potential and ground to give a potential gradient in the diagonal direction (Japanese Patent No. 4168537 (Patent Document 2)).

  In general, the resistance value of the resistive surrounding electrode 3 is set lower than the resistance value of the surface resistor 2 surrounded by the resistive surrounding electrode 3 in order to improve the linearity of coordinates. However, when the ratio of the resistance value of the surface resistor 2 to the resistance value of the resistive surrounding electrode 2 cannot be made sufficiently large, the coordinates as the calculation result may deviate from the correct position. However, the deviation caused by this factor has such a property that the straight line is distorted into a pincushion shape over the entire area of the surface resistor 2.

  As described above, as a method for correcting the detected coordinate deviated from an accurate position, for example, it is disclosed in Japanese Patent No. 3505970 (Patent Document 3) and Japanese Patent Application Laid-Open No. 2010-237913 (Patent Document 4) by the same applicant. Something like that is known. In the method disclosed in Patent Document 3, the input range is actually divided into a grid having square cells, and the actual reference coordinate value of the grid point position and the position of the reference coordinate are actually indicated by the coordinate indicator. Reference detection coordinate values to be detected are stored in advance at the time of manufacture, and for coordinates detected in a specific cell of a lattice formed (distorted) using the reference detection coordinates as lattice points, a horizontal line passing through the coordinates and The coordinates are corrected based on the information of the point where the vertical line intersects the four sides of the cell.

  However, in both methods, the correction target area is divided into a grid and correction is performed for each cell. Therefore, if local distortion occurs in an area smaller than the cell size, correction is performed. There was a case that could not be done. As a cause of such local distortion, there may be a case where a local defect or a local resistance value abnormality exists in the surface resistor 2 that should be uniform. If the local defect is extremely small, it does not hinder the flow of current flowing in the vicinity, and thus does not become a problem. However, if it has a certain size, it causes a deviation in the calculation result of the coordinates in the vicinity. Similarly, deviation also occurs when there is a region where the resistance value is locally larger or smaller than the surrounding area.

  In addition, as a non-electrostatic coupling method, the resistive film method has two surface resistors arranged in opposition with a gap, and the two surface resistors are in contact with each other at a position pressed with a finger or an input pen. Then, the coordinates of the pressed position are calculated by detecting a signal for driving one of the sheet resistors from the other sheet resistor. In the resistive film method, as in the electrostatic coupling method, it is possible to correct the distortion over the entire surface resistor, but if there is a local defect or an abnormal resistance value, the correction may not be possible. there were.

In such cases, as a countermeasure, it is conceivable to divide the correction target area with a smaller grid, but the number of coordinates that must be stored in advance increases, and the number of man-hours at the time of manufacture also increases. Therefore, the size of the lattice cell cannot be reduced so much as an actual product.
Under such conditions, it is necessary to evaluate by inspection whether there is a coordinate shift due to local defects or abnormal resistance values in the product. If there is an unacceptable coordinate shift, the individual is determined to be defective. For example, as disclosed in Japanese Patent Application Laid-Open No. 2005-190236 (Patent Document 5), a method of measuring a signal at a plurality of measurement points set in a matrix and evaluating linearity is conceivable.

  Another possible method is to draw a straight line with an input pen using a ruler or a robot and evaluate the linearity of a series of coordinate groups calculated based on the detected signal. For example, when a horizontal or vertical straight line is drawn and the minimum and maximum deviations from the correct position of the coordinate axis of the coordinate axis orthogonal to the straight line direction exceed the default value, there is some abnormality near the straight line. It can be judged that there is. However, when there is a local distortion between two adjacent straight lines, there is a possibility that the deviation in the position of the straight line does not become so large that it can be determined that it is abnormal. Therefore, in order to detect local distortion, it is necessary to draw a straight line as finely as possible.

Japanese Patent No. 3237629 Japanese Patent No. 4168537 Patent 3505970 JP 2010-237913 A JP 2005-190236 A

The present invention has been made in consideration of such points, and by evaluating the linearity of a series of coordinate groups as a result of detection and calculation of input straight lines, the number of input straight lines is suppressed as much as possible. However, an object of the present invention is to provide an evaluation / inspection method that detects local distortion.

The present invention is an evaluation method for detecting a local resistance value abnormality of a surface resistor constituting a coordinate input area in a coordinate input system that detects and outputs a position indicated by a coordinate indicator such as a finger or a pen. In the coordinate input area, a plurality of straight lines are input at predetermined intervals in two directions orthogonal to each other by the coordinate indicator, and the output coordinate group of the coordinate input system corresponding to the straight lines is It is determined whether or not there is a local bend having a magnitude greater than or equal to one threshold, and when there are at least a plurality of the local bends in a specific region, the plurality of local bends are grouped together. An evaluation method of a coordinate input system, characterized in that it is determined that a local resistance value abnormality of the surface resistor exists in the region.

According to the evaluation method of the coordinate input system according to the present invention, it is possible to detect a local resistance value abnormality while suppressing the number of straight lines to be reduced.

Schematic diagram showing an example of a coordinate input system Flowchart showing an example of a method for detecting a local resistance value abnormality Flow chart showing an example of a bending group determination method The flowchart which shows another example of the bending group determination method The figure which shows the example of the output coordinate group of 1st Example, and local bending The figure which shows the example of the output coordinate group of 2nd Example, and local bending The figure which shows the example of the output coordinate group of 3rd Example, and local bending Schematic diagram showing a rectangular coordinate input panel

Hereinafter, preferred embodiments of a coordinate input system according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of a coordinate input system used in the evaluation method of the coordinate input system according to the present embodiment. The surface resistor 12 is uniformly formed on one surface of transparent glass, resin, or opaque insulating base material by coating, vapor deposition, or the like. The surface of the surface resistor 12 is insulated so that the input pen 21 does not directly touch the surface resistor 12, thereby transmitting signals by capacitive coupling between the input pen 21 and the surface resistor 12.
A rectangular resistive surrounding electrode 13 with each side being a straight line is disposed in close contact with or around the surface resistor 12, and the inside of the resistive surrounding electrode 13 is defined as a rectangular coordinate input region 18.
Drive electrodes 14 to 17 are formed at positions corresponding to the apexes of the rectangular coordinate input region 18 on the resistive surrounding electrode 13, and lead lines 22 to 25 are connected to the drive electrodes 14 to 25, respectively. The lead lines 22 to 25 include external resistance components 26 to 29, respectively. The lead lines 22 to 25 are connected to the drive electrode changeover switch 30.

The surface resistor 12 is made of an opaque carbon film, a transparent ITO (indium tin oxide) film formed by sputtering, a NESA (tin oxide) film formed by CVD, or the like uniformly on a substrate. The film is formed, and the surface resistance is preferably about 1 KΩ / □. For example, soda glass can be used as the substrate, but the material is not particularly limited, and any glass material or a transparent resin material such as an acrylic resin or a polyethylene resin can be used. Depending on the application, an opaque insulating substrate may be used.
A rectangular resistive peripheral electrode 13 having straight sides is provided around or inside the surface resistor 12 so that all sides are in electrical contact with the surface resistor 12. The resistive surrounding electrode 13 surrounding the surface resistor 12 is formed by closely arranging carbon, silver carbon, silver, or the like. For example, a technique such as screen printing and baking of conductive ink such as silver ink is used. Create with. Each side of the resistive surrounding electrode 13 may be a straight line having a width, or low resistance conductive elements are arranged separately from each other and formed by utilizing the resistance of the surface resistor 12. But you can. The resistive surrounding electrode 13 makes the resistance value per length constant at least for each side, preferably for each opposite side.
Further, the resistance value of the resistive surrounding electrode 13 is preferably lower than the resistance value of the sheet resistor 12. When the sheet resistance value of the sheet resistor 12 is about 1 KΩ / □, The resistance value between adjacent vertices is preferably about 20 to 200Ω.

The drive electrodes 14 to 17 at the respective apexes are for connecting the lead lines, and are formed by printing and baking a solderable conductive ink. When the same conductive ink as the resistive surrounding electrode 13 can be used as the conductive ink for forming the driving electrodes 14 to 17, the driving electrodes 14 to 17 and the resistive surrounding electrode 13 are It is possible to form by printing and baking by processing.
The shape of the resistive surrounding electrode 13 and the surface resistor 12 may be any shape as long as it can be accommodated in the substrate, and the shape of the resistive ambient electrode 13 and the sheet resistor 12 and the substrate need not be substantially matched. It is preferable that the shape of the base electrode is the same as the shape of the surrounding electrode 13 and the surface resistor 12 because the degree of freedom in designing the incorporated product is increased when the coordinate input system is incorporated into any product.
The external resistance components 26 to 29 are the totals of the resistance components included in the elements such as the lead lines 22 to 25, the drive electrode changeover switch 30, and the signal generator 31 for each path emanating from each of the drive electrodes 14 to 17. Generally, the resistance inherent in the lead lines 22 to 25 occupies a large portion of them. In the case of using sufficiently low resistance lead wires or the like as the lead wires 22 to 25, the external resistance components 26 to 29 are extremely smaller than the resistance value of the resistive surrounding electrode 13, and in calculating the coordinates, It will not be necessary to consider it independently. On the other hand, for example, when the extension of the lead wires 22 to 25 is long or the resistance is relatively high depending on the material and shape of the lead wires 22 to 25, the external resistance components 26 to 29 may be large. These can be corrected if the resistance value of each part is known.

In order to detect the coordinates, an AC potential gradient is applied to the surface resistor 12 by the signal generator 31 which is a potential output means. The potential gradient is given by a combination in which the diagonals of the rectangular coordinate input area 18 are simultaneously connected by the drive electrode changeover switch 30. That is, the following four combinations exist. First, the drive electrode 14 is connected to the output side of the signal generator 31, the drive electrode 16 is connected to the ground side, and the drive electrodes 15 and 17 are disconnected. Second, the connection between the output side and the ground side of the drive electrodes 14 and 16 with respect to the signal generator 31 is switched while the drive electrodes 15 and 17 are not connected. Third, the drive electrode 15 is connected to the output side of the signal generator 31, the drive electrode 17 is connected to the ground side, and the drive electrodes 14 and 16 are disconnected. Fourth, the connection between the output side and the ground side of the drive electrodes 15 and 17 with respect to the signal generator 31 is switched while the drive electrodes 14 and 16 are not connected.

In each of these connection states, the AC signal level of the surface resistor 12 at a position close to the tip of the input pen 21 is transmitted to the input pen 21 through the capacitive coupling, and further, the analog signal processing unit through the cable 32. 33. Although not shown, the analog signal processing unit 33 includes an amplifier, a band pass filter, an AC / DC converter (AM detector), and the like, and outputs a DC signal level proportional to the input AC signal level. The CPU 35 inputs the digital value output from the A / D converter 34 and calculates the indicated position of the input pen 21.
Of the measured values of the potential near the tip of the input pen 21, the drive electrode 14 (vertex A) is connected to the output side of the signal generator 31 and the drive electrode 16 is connected to the ground side by the drive electrode changeover switch 30. The measured value when the drive electrodes 15 and 17 are not connected is the measured value A, the drive electrode 15 (vertex B) is connected to the output side of the signal generator 31, the drive electrode 17 is connected to the ground side, and the drive electrode 14 Measured value B when no and 16 are disconnected, measured value B, drive electrode 16 (vertex C) is connected to the output side of signal generator 31, drive electrode 14 is connected to the ground side, and drive electrodes 15 and 17 are disconnected. Measured value when measured value C, drive electrode 17 (vertex D) is connected to the output side of signal generator 31, drive electrode 15 is connected to the ground side, and measured value when drive electrodes 14 and 16 are not connected. Is a measured value D. At this time, when the resistance value of the external resistance components 26 to 29 can be ignored, the position of the input pen 21 is, for example, the horizontal direction is the X axis and the right is positive, the vertical direction is the Y axis and the bottom is positive, and the origin is When the range of the coordinate input area 18 is normalized to X = [− 1, 1] and Y = [− 1, 1] with the center of the coordinate input area 18, X = 2 (B + C−A−D) / (A + B + C + D). ), Y = 2 (C + D−A−B) / (A + B + C + D).

  Depending on the ratio between the resistance value of the resistive surrounding electrode 13 and the resistance value of the surface resistor 12, the coordinates of the calculation result may be distorted in a pincushion shape over the entire area of the surface resistor 12. Such a distortion is actually detected when, for example, the coordinate input area 18 is divided into a grid having square cells, and the accurate reference coordinate value of the grid point position and the position of the reference coordinate are indicated by the coordinate indicator. The reference detection coordinate value to be stored is stored in advance at the time of manufacture, and for the coordinates detected in a specific cell of the (distorted) grid formed using the reference detection coordinates as the grid points, a horizontal line and a vertical line passing through the coordinates are detected. Correction can be made based on the information of the point where the line intersects the four sides of the cell.

The current in the surface resistor 12 such as a defect having a size as small as a pinhole generated on the surface resistor 12 according to the film forming method (region in which the substance forming the surface resistor 12 is not fixed) If it does not obstruct the macroscopic flow, it does not matter at all. In the case where a larger defect occurs due to damage or the like, the coordinates are shifted from the designated position according to the size of the defect at least around the defect. Although the influence on the coordinate calculation of the indicated position of the input pen 21 decreases as the distance from the defect increases, depending on the size of the defect, a shift in coordinates at least immediately near the defect may increase to an unacceptable level. In addition, there is a local resistance value abnormality (for example, a region where the substance forming the surface resistor 12 is fixed, but the amount is not sufficient and the resistance value is higher than the surrounding area). In some cases, the same problem may occur depending on the degree of resistance value abnormality and the size of the region. Hereinafter, the defect and the resistance value abnormality are collectively referred to as resistance value abnormality.

  A method for detecting a local resistance value abnormality will be described with reference to FIGS. 2, 3, and 4. First, a straight line is drawn in the coordinate input area 18 with the input pen 21, and coordinate data calculated by the CPU 35 is input as an output coordinate group for each straight line (S101). In order to draw a straight line, the input pen 21 may be attached to the robot, or a straight ruler may be placed on the coordinate input area 18 and the input pen 21 may be moved manually along the ruler. .

  The evaluation of the output coordinate group corresponding to a certain straight line is performed by calculating a straight line from the data of the output coordinate group and calculating the distance between the straight line and each coordinate data belonging to the output coordinate group. In order to calculate a straight line from the data of the output coordinate group, a well-known least square method can be used. However, if there is a local bend in the output coordinate group, the calculation also includes data belonging to the local bend, so the straight line of the calculation result slightly protrudes from the straight line. Deviate in the direction. In order to calculate a straight line on which most of the data of the output coordinate group exists even in the presence of a local bend, a well-known weighted least square method is repeatedly applied. Can be used. This is to add a weight to each term of the residual sum of squares to be minimized so that the data farther from the straight line obtained by the least square method becomes smaller, and to minimize the residual sum of squares to which the weight is added again. This is a method of recalculating a straight line. The newly calculated straight line is closer to the straight line on which most data of the output coordinate group exists than the previously calculated straight line. By repeating this until the calculation result converges, it is possible to calculate the straight line while eliminating the influence of local bending (S102).

The distance between the straight line thus obtained and each coordinate data belonging to the output coordinate group is an expression representing the distance d between the point (x, y) and the straight line y = ax + b, d = | y− It can be calculated using (ax + b) | / √ (1 + a ² ). A certain bend is defined as a group of coordinates that are consecutive in the output order, separated by a predetermined distance or more on either side of the calculated straight line. The predetermined distance here is a reference for determining that the coordinates belonging to the output coordinate group have deviated from the straight line, and is set as small as possible in accordance with the resolution of the coordinate input system to be evaluated. The maximum value of the distance from the straight line of the coordinate group belonging to one bend is defined as the magnitude of the bend (S103).

  Regarding the output coordinate group corresponding to a certain straight line, there may be a case where the magnitude of any one of the bends is so large that it can be determined as a defect alone (S104). When it is large enough to be judged as a defect alone, the accuracy specified as the specification of the coordinate input system to be evaluated cannot be satisfied immediately on the input straight line. It means that it is above the threshold. This threshold is hereinafter referred to as the zeroth threshold. In such a case, there is no problem in determining the defect (S105).

Therefore, if a straight line is input without any difference in the coordinate input area 58, the output coordinate group corresponding to each straight line may be evaluated individually. However, it takes too much time and is not realistic.
Therefore, two directions orthogonal to each other are set in the coordinate input area 58, straight lines are input at predetermined intervals in each direction, and output coordinate groups corresponding to them are evaluated. Hereinafter, the two directions orthogonal to each other are defined as the X axis and the Y axis defined above. The interval for inputting the straight line may be changed between the straight line group parallel to the X axis and the straight line group parallel to the Y axis, or may be the same. However, if the interval is too large, there is a possibility that the local resistance value influence does not reach the position where the straight line is input. Therefore, the interval between these straight lines is smaller than the zeroth threshold value, although the zeroth threshold value is not exceeded at the position where the straight line is input when there is an abnormality in the resistance value at the midpoint between the adjacent straight lines. It is necessary to set the size to such an extent that it can be assumed that a local bend having a size greater than or equal to the first threshold value occurs. The first threshold value is set to such a size that it cannot be immediately judged as defective when a local bend having such a magnitude exists alone. As a result, at least two local bends having a magnitude greater than or equal to the first threshold value due to the local resistance value abnormality occur in the vicinity of the resistance value abnormality. These multiple local bends are defined as bend groups. When all the straight line groups parallel to the X axis and the straight line group parallel to the Y axis are input (S106), a bending group determination is performed based on the output coordinate group corresponding to each straight line (S107).

  One method for determining a bending group is shown in FIG. When the interval between the straight lines and the first threshold value are set as described above, if there is a local resistance value abnormality at the midpoint between two parallel straight lines in the coordinate input area 18, 2 A local curve having a magnitude greater than or equal to the first threshold value occurs in both of the output coordinate groups corresponding to the book straight line. For example, if there is a local resistance abnormality at the midpoint between two straight lines that are adjacent in parallel to the Y axis, each of the output coordinate groups corresponding to the two straight lines has a direction perpendicular to the Y axis. That is, when viewed from a direction parallel to the X axis, a local bend that has an overlapping portion occurs. Therefore, for each of a plurality of output coordinate groups corresponding to a straight line parallel to the X axis and a plurality of output coordinate groups corresponding to a straight line parallel to the Y axis, an output coordinate group corresponding to the straight line at the end is first selected. (S111), the output coordinate group includes a local curve having a magnitude equal to or larger than the first threshold (S112), and the output coordinate group corresponding to a straight line adjacent to the straight line also includes If there is a local bend having a size greater than or equal to the first threshold value, such as having overlapping regions when viewed from the direction perpendicular to the direction in which the straight line extends (S113), the bend group is It can be determined that it exists (S114). If the output coordinate group includes other local bends having a magnitude equal to or larger than the first threshold (S115), the same evaluation is performed for the output coordinate group corresponding to the parallel straight lines. Perform (S113). In the output coordinate group, if there is no local bend having a magnitude greater than or equal to the first threshold, or if all the local bends have been evaluated, there is a straight line adjacent to the straight line (S116). The straight line is selected (S117), and the same evaluation is performed (S112). When all the straight lines have been evaluated, the process ends.

  If the interval between the straight lines and the first threshold are set more severely, when such a region is detected, a local resistance value abnormality exists in the region, and the coordinate input system to be evaluated is defective. You may make it judge that it is. Alternatively, if the interval between the straight lines and the first threshold value are not set so strictly, after detecting such a region, the straight lines are input at finer intervals only within the region, and those straight lines are input. It may be additionally evaluated whether or not a bend having a magnitude greater than or equal to the zero threshold occurs in the output coordinate group corresponding to.

When the resistance value abnormality is a defect and the resistance value becomes high such that the substance constituting the surface resistor 12 is not sufficiently fixed, the local bending that occurs in a straight line is a region having the resistance value abnormality. It is formed in a shape away from That is, when such a resistance abnormality exists between two parallel straight lines, the local bend generated in both of the straight lines has a direction in which the bend protrudes in parallel 2 Each line is outside the book.
On the other hand, in the case where the resistance value is low, such as when the resistance value abnormality is such that a large amount of the substance constituting the surface resistor 12 is locally fixed, the local bending that occurs in the straight line is the resistance value abnormality. It is formed in a shape that approaches a certain region. That is, the direction in which the curve protrudes is inside each straight line adjacent in parallel.

Further, when the local resistance value abnormality is in a relatively wide range, the direction in which the local bending occurs in the output coordinate group corresponding to each of the two parallel straight lines is the same. Sometimes it is.
For example, when it can be assumed that there is a low possibility of occurrence of a resistance value abnormality in which the resistance value decreases depending on the film forming method, the output corresponding to each of two straight lines adjacent in parallel to the Y axis The coordinate group has an overlapping portion when viewed from a direction parallel to the X axis, and when a local bend having a size equal to or greater than the first threshold occurs, the direction in which the bend protrudes is If they were inside each of the straight lines adjacent in parallel, those bends did not occur because there was a local resistance anomaly with low resistance in the middle of both, but on the outside of both, individually, It is possible to determine that the problem has occurred because there is a local resistance value abnormality with a high resistance value that does not cause a problem.

FIG. 4 shows another method for determining a bending group. An abnormal resistance value is located at a position near one straight line from an intermediate point between two straight lines adjacent in parallel to the X axis, and from one intermediate point between two straight lines adjacent in parallel to the Y axis. If it exists at a position closer to the straight line, the output coordinate group corresponding to a total of two lines, that is, a straight line parallel to the X axis and a straight line parallel to the Y axis, closer to the resistance value abnormality, A local bend having a magnitude greater than or equal to the threshold value occurs.
That is, for a cell that is partitioned in a lattice pattern by a group of two lines in the direction parallel to the X axis and the direction parallel to the Y axis, for example, a local resistance value abnormality has shifted to the lower left from the center of a certain cell. If it exists at a position, a bend having a magnitude greater than or equal to the first threshold value occurs in the output coordinate group corresponding to at least the left vertical side and the lower horizontal side. If a bend with a magnitude greater than or equal to the first threshold value occurs only in the output coordinate group corresponding to at most one of the four sides constituting the cell, an abnormal resistance value is problematic. Is unlikely to exist in the cell.

Therefore, each set of output coordinate groups corresponding to two sets of two sides parallel to each other among the four sides of each cell has at least one or more, a total of two or more in total of four sides, and a size greater than or equal to the first threshold value. When there are local bends having a certain length, the plurality of local bends can be determined as a bend group. However, local bending may extend over a plurality of cells adjacent to each other. Therefore, for a certain cell (S121), if at least one local bend having a magnitude greater than or equal to the first threshold exists on any of the four sides of the cell (S122), those local Evaluate whether there is a curve that spans a plurality of adjacent cells (S123). If there is a bend, combine the cells that are adjacent to each other (S124). For one side, one or more output coordinate groups corresponding to two or more straight lines parallel to the X axis and one output coordinate group corresponding to two or more straight lines parallel to the Y axis As described above, when there are local bends having a magnitude greater than or equal to the first threshold (S125), the plurality of local bends may be defined as a bend group. When the cells are integrated, all the cells belonging to the integrated cells are evaluated, and the evaluation is repeated until there is no unevaluated cell (S127).
As described above, the region where the detected bending group exists may be determined as defective according to the interval between the straight lines and the first threshold value, or the straight lines may be formed at finer intervals within the region. It is also possible to additionally evaluate whether or not a bend having a magnitude greater than or equal to the zeroth threshold occurs in the output coordinate group corresponding to those lines.

  Further, the first threshold value is set smaller, the second threshold value is set larger than the first threshold value and smaller than the zeroth threshold value, and the bend detected as described above with reference to the first threshold value. Regarding a group, if any of the local bends belonging to the bend group has a magnitude greater than or equal to the second threshold, there is a local resistance abnormality in the region where the bend group exists. You may make it judge. By doing so, it is determined that there is a local resistance abnormality only when a group of smaller local bends is detected, and only those having relatively large bends exist. The distance between the straight lines can be increased.

  All or part of the above methods can be implemented as a computer program to be executed by a general-purpose computer or processor, and such a program can be stored in a computer-readable storage medium. Examples of computer-readable storage media include ROM (Read Only Memory), RAM (Random Access Memory), semiconductor memory such as a flash drive, magnetic media such as a hard disk, and optical media such as CD-ROM and DVD-ROM. .

Hereinafter, the present invention will be described by way of examples. The present invention is not limited to the following examples, and includes various modifications within the technical scope of the present invention.

(Example 1)
FIG. 1 shows the configuration of the coordinate input system. The coordinate indicator (input pen) 21 detects the coordinates (X, Y) of the position designated in the rectangular coordinate input area 18 of the coordinate input panel 11. As the surface resistor 12, a NESA (tin oxide) film was formed in a rectangular shape on a square glass substrate. The resistive surrounding electrodes 13 were formed on the four sides of the coordinate input area 18 by screen printing with silver carbon ink. Furthermore, the coordinate input area 18 is insulated with a glass coating agent, thereby transmitting a signal by capacitive coupling between the input pen 21 and the surface resistor 12.

Further, the coordinate detection is performed as described in the <Embodiment>, and the detected coordinate value is output from the CPU 35 and taken into the personal computer by serial communication. The steps of S101 to S107 and S111 to S117 were created as a program that can be executed on a personal computer and stored in a hard disk built in the personal computer. The same applies to the subsequent examples.
A straight line ruler is placed horizontally and vertically on the input panel 12, the input pen 21 is moved along the ruler, and the ruler is moved at a predetermined interval each time a straight line is drawn. The group was entered on the computer side. As for the combination of the interval for drawing a straight line and the first threshold, the interval between the straight lines was set to 40 mm and the first threshold was set to 1.5 mm in the program. However, the straight line spacing was 40 mm in the X-axis direction and 30 mm in the Y-axis direction. When it is narrower than the set interval, no problems other than the increase in man-hours occur. In the present embodiment and the following embodiments, a case where the resistance is locally high is detected as a local resistance value abnormality.

FIG. 5 shows an example of the operation result of the program when a local curve having a magnitude greater than or equal to the first threshold occurs in the output coordinate group corresponding to two straight lines adjacent in parallel. FIG. 5A shows a line drawn by connecting output coordinate groups for each corresponding straight line in the vicinity of the detected local resistance value abnormal region. FIG. 5B shows a picture in which a region protruding from a corresponding straight line is filled in for a local bend having a magnitude greater than or equal to the first threshold. The plurality of local bends occur in output coordinate groups corresponding to adjacent straight lines parallel to the Y axis, and have regions that overlap each other when viewed from the X axis direction. Further, the direction in which the curve protrudes is the direction outside the X-axis direction, that is, the direction opposite to the adjacent straight line. Thereby, it was possible to detect the presence of a local resistance value abnormality having a high resistance in the region.

(Example 2)
Output coordinates corresponding to two sets of two sides that are parallel to each other among the four sides of each cell, with respect to the cells that are partitioned in a lattice pattern by two groups of straight lines in the direction parallel to the X axis and the direction parallel to the Y axis FIG. 6 shows an example of the result in the case where each group of groups includes a local bend having a size of at least one or more, a total of two sides of two or more, and a first threshold value or more. FIG. 6A shows a line drawn by connecting output coordinate groups for each corresponding straight line in the vicinity of the detected local resistance value abnormal region. FIG. 6B shows a picture in which a region protruding from a corresponding straight line is filled with a local curve having a magnitude equal to or larger than the first threshold. In the output coordinate group corresponding to the straight line parallel to the X axis, three local bends having a magnitude greater than or equal to the first threshold value extend over two cells adjacent in the X axis direction, In the output coordinate group corresponding to the parallel straight line, a local bend having a magnitude equal to or larger than the first threshold value extends over three cells adjacent to each other in the Y-axis direction. A local bend having a magnitude greater than or equal to the threshold is detected. Thereby, it was possible to detect the presence of a local resistance value abnormality having a high resistance in the region.

(Example 3)
The first threshold value is 1.0 mm, the second threshold value is 2.0 mm, and the bending group detected based on the first threshold value includes a local bending having a magnitude greater than or equal to the second threshold value. An example of the result when it exists is shown in FIG. FIG. 7A shows a line drawn by connecting output coordinate groups for each corresponding straight line in the vicinity of the detected local resistance value abnormal region. FIG. 7B shows a picture in which a region protruding from a corresponding straight line is filled with a local bend having a magnitude equal to or larger than the first threshold. Two local bends having a magnitude greater than or equal to the first threshold in the output coordinate group corresponding to the straight line parallel to the X axis have been detected, but both have magnitudes less than the second threshold. Two local bends having a magnitude greater than or equal to the first threshold in the output coordinate group corresponding to the straight line parallel to the Y axis are detected, and the local bend magnitude on the left side is the second bend. Has a size greater than or equal to the threshold. Thereby, it was possible to detect the presence of a local resistance value abnormality having a high resistance in the region.

DESCRIPTION OF SYMBOLS 1 Coordinate input panel 2 Surface resistor 3 Resistive surrounding electrode 4, 5, 6, 7 Detection electrode 8 Coordinate input surface 11 Coordinate input panel 12 Surface resistor 13 Resistive surrounding electrode 14, 15, 16, 17 Drive electrode 18 Coordinate Input surface 21 Input pens 22, 23, 24, 25 Lead lines 26, 27, 28, 29 External resistance component 30 Drive electrode changeover switch 31 Signal generator 32 Cable 33 Analog signal processing unit 34 A / D converter 35 CPU

Claims (6)

In the coordinate input system for detecting and outputting a position indicated by a coordinate indicator such as a finger or a pen, an evaluation method for detecting a local resistance value abnormality of a surface resistor constituting a coordinate input area, wherein the coordinates Inside the input area, a plurality of straight lines are input at predetermined intervals in two directions orthogonal to each other by the coordinate indicator, and the output coordinate group of the coordinate input system corresponding to the straight lines is equal to or greater than a first threshold value. It is determined whether or not there is a local bend having a size of. When there are at least a plurality of the local bends in a specific region, the plurality of local bends are regarded as a group of bends. A method for evaluating a coordinate input system, wherein it is determined that a local resistance value abnormality of the surface resistor exists in the region. The local bend exists in any of the output coordinate groups corresponding to the straight lines that are adjacent to each other in at least one of the two directions orthogonal to each other, and is perpendicular to the direction in which the straight line extends. When the local bends existing in each of the output coordinate groups have overlapping portions when viewed, the plurality of local bends are grouped into a bend group, and the bend group exists in an area where the bend group exists. The coordinate input system evaluation method according to claim 1, wherein it is determined that a local resistance value abnormality of the surface resistor exists. For each cell of the lattice constituted by a plurality of straight lines in two directions orthogonal to each other, at least one set of output coordinate groups corresponding to two sets of two sides parallel to each other among the four sides of each cell. When there are two or more local bends in total of four or more sides, the plurality of local bends are taken as a group of bend groups, and the surface resistor is formed in a region where the bend groups exist. The coordinate input system evaluation method according to claim 1, wherein it is determined that there is a local resistance value abnormality. When at least one of the plurality of local bends belonging to the bend group has a magnitude greater than or equal to a second threshold value that is greater than the first threshold value, in the region where the bend group exists, The coordinate input system evaluation method according to claim 2, wherein it is determined that a local resistance value abnormality of the surface resistor exists. The program for making a computer perform the evaluation method of the coordinate input system in any one of Claims 1 thru | or 4. A computer-readable storage medium storing the program according to claim 5.

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