JP2014235479A - Touch input device, touch input correcting method, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve accuracy in computing of a pressing force coordinate in a case of small pressing force.SOLUTION: A touch input device comprises: a flat plate part; a plurality of force sensors that are respectively disposed at a plurality of positions of the flat plate part and detect force received from the flat plate part; and a computing part that stores a plurality of pieces of correction information to correct a pressing force coordinate in association with pressing force indicating force of pressure to the surface of the flat plate part and the pressure force coordinate indicating a position of the pressure, that detects first pressing force on the basis of output of the plurality of force sensors, that computes a first pressing force coordinate on the basis of the output of the plurality of force sensors and the plurality of positions, that selects first correction information from among the plurality of pieces of correction information on the basis of the first pressing force and the first pressing force coordinate; and that corrects the first pressing force coordinate using the first correction information.

Description

  The present invention relates to a touch input device, a touch input correction method, and a computer program.

  There is known a touch input device such as a touch panel that receives an input by touching a display surface. As a method for detecting the XY coordinates of the touched position on the touch panel, a resistance film method, a capacitance method, a force sensor method, and the like are known. The force sensor type touch panel can detect the pressing pressure in addition to the XY coordinates.

  In Patent Document 1, since a touch panel is realized by using a glass plate and a force sensor as an operation panel, a film having light loss as in a resistive film type or a capacitance type is not required. It is described that the transmittance increases.

  Patent Document 2 describes a technique for eliminating an initial unstable detection value by applying an initial load to a pressure detection unit in advance.

  Patent Document 3 describes a technique for calibrating the output of a sensor using calibration parameters indicating manufacturing variations.

JP 2005-78194 A JP 2010-238176 A Japanese Patent No. 3278117

  The force sensor type touch input device detects minute displacements of the panel with multiple force sensors, so when the touch is low load, it is affected by the material of the panel and the assembly method of the force sensor. There is a problem that the calculation accuracy of is reduced.

  In addition, in the technique of eliminating an initial unstable detection value by applying an initial load in advance, the calculated coordinates are not stable in the long term due to a change with time of an elastic member or the like. Moreover, since the range of the displacement which can be detected becomes small, there exists a problem that the range of the pressing force calculated from a displacement will become narrow.

  The present invention has been made in view of the above problems, and an object thereof is to provide a technique for improving the accuracy of calculation of the press coordinates when the pressing force is small.

  A touch input device according to one aspect of the present invention includes a flat plate portion, a plurality of force sensors that are disposed at a plurality of positions of the flat plate portion, detect a force received from the flat plate portion, and a pressure on the surface of the flat plate portion. A plurality of correction information for correcting the pressing coordinates are stored in association with the pressing force indicating the force and the pressing coordinates indicating the position of the pressing, and the first pressing force is detected based on the outputs of the plurality of force sensors. And calculating the first pressing coordinates based on the outputs of the plurality of force sensors and the plurality of positions, selecting the first correction information from the plurality of correction information based on the first pressing force and the first pressing coordinates, And an arithmetic unit that corrects the first press coordinates using the first correction information.

  The display unit further includes a display unit that includes a display area that displays a screen based on information from the calculation unit, and the display region is covered with a flat plate unit, the flat plate unit transmits the display, and the calculation unit is provided in the display region. A plurality of reference coordinates are stored, instruction information for instructing the user to press the specific coordinates is displayed on the display area with respect to the specific coordinates that are each of the plurality of reference coordinates. By calculating the pressing force and calculating the second pressing coordinates based on the outputs of the plurality of force sensors and the plurality of positions, a plurality of second pressing coordinates corresponding to the plurality of reference coordinates are calculated, and a plurality of second pressing coordinates are calculated. Second correction information for converting each of the two pressed coordinates into a plurality of reference coordinates may be calculated, and the second correction information may be stored as one of the plurality of correction information.

  The second correction information may be a coefficient for projective transformation from a plurality of second pressed coordinates to a plurality of reference coordinates.

  When the first pressing force is within a predetermined range, the calculation unit selects the first correction information from the plurality of correction information based on the first pressing force and the first pressing coordinate from the plurality of correction information. You may do it.

The block diagram which shows the structure of the touchscreen of an Example. The perspective view which shows the structure of the panel part 100. FIG. FIG. 3 is an exploded perspective view showing the configuration of the panel unit 100. The top view which shows the coordinate system of the panel part 100 surface. The top view which shows a correction area. The flowchart which shows a correction coefficient calculation process. The top view which shows the display of a reference coordinate. The top view which shows a reference | standard coordinate and a press coordinate. The flowchart which shows an input detection process. The top view which shows the modification of a correction area.

  The touch input device of this embodiment can improve the accuracy of the press coordinates with respect to a wide range of pressing forces by correcting the pressing coordinates using a correction coefficient corresponding to the pressing coordinates and the pressing force.

  The touch input device of the present embodiment includes a touch panel, a touch pad, a portable information terminal (including a mobile phone, a smartphone, a camera, a personal computer, etc.), a vehicle (including a car navigation device), a kiosk terminal, an ATM (Automated Teller Machine). ), A vending machine (including an automatic ticket vending machine, etc.) and the like may be applied to a system that accepts an operation by pressing the touch surface. The touch input device according to the present embodiment may be applied to an HMI (Human Machine Interface) device that is connected to a computer and performs input / output.

  Hereinafter, examples of the touch panel to which the present invention is applied will be described.

  FIG. 1 is a block diagram illustrating a configuration of the touch panel of the embodiment.

  The touch panel of the present embodiment includes a panel unit 100, a signal conversion unit 500, a calculation unit 200, an application execution unit 300, and a display control unit 410.

  The panel unit 100 outputs four output signals indicating the forces applied to the four locations of the panel unit 100 to the signal conversion unit 500. The signal conversion unit 500 includes four A / D conversion units 510 corresponding to the four output signals output from the panel unit 100, respectively. The A / D converter 510 converts an analog output signal into a digital output value at a predetermined sample period by A / D conversion. The calculation unit 200 detects an input to the panel unit 100 based on the output value, and outputs the detected input to the application execution unit 300. The application execution unit 300 executes the application based on the detected input, generates screen information based on the execution result, and outputs the screen information to the display control unit 410. The display control unit 410 further generates a display signal for controlling the panel unit 100 based on the screen information, and outputs the display signal to the panel unit 100. Panel unit 100 displays a screen based on the display signal.

  The calculation unit 200 includes a pressing force calculation unit 710, a pressing coordinate calculation unit 720, a correction coefficient calculation unit 810, and a pressing coordinate correction unit 820. The pressing force calculation unit 710 acquires an output value from the signal conversion unit 500 at a predetermined measurement cycle, and calculates a measurement value that indicates a variation in the output value. Further, the pressing force calculation unit 710 calculates a pressing force indicating the pressing force based on the measurement value. Furthermore, the press coordinate calculation unit 720 calculates the press coordinates that are the coordinates of the press based on the measurement value. The display control unit 410 generates a display signal for controlling the display of the panel unit 100 based on the screen information from the application execution unit 300, and outputs the display signal to the panel unit 100. The correction coefficient calculation unit 810 executes a correction coefficient calculation process for calculating a correction coefficient for correcting the pressed coordinates. The pressed coordinate correction unit 820 calculates the corrected pressed coordinate by correcting the pressed coordinate using the correction coefficient.

  The calculation unit 200, the application execution unit 300, and the display control unit 410 are realized by a computer, for example. This computer has a memory for storing programs and data, and a microprocessor such as a CPU (Central Processing Unit) that executes processing of the arithmetic unit 200, the application execution unit 300, and the display control unit 410 according to the program. This program may be stored in a computer-readable medium and read from the medium to the computer. Note that the arithmetic unit 200, the application execution unit 300, and the display control unit 410 may be realized by different microprocessors. Further, the application execution unit 300 and the display control unit 410 may be realized by a single microprocessor. In addition, programs corresponding to each of the calculation unit 200, the application execution unit 300, and the display control unit 410 may be prepared. Note that any of the calculation unit 200, the application execution unit 300, and the display control unit 410 may be realized by a dedicated electronic circuit. In addition, either the application execution unit 300 or the display control unit 410 may be provided outside the touch panel. In this case, the arithmetic unit 200 has a communication interface and performs communication with the outside of the touch panel. Note that the arithmetic unit 200 may include a signal conversion unit 500.

  FIG. 2 is a perspective view showing the configuration of the panel unit 100, and FIG. 3 is an exploded perspective view showing the configuration of the panel unit 100.

  The panel unit 100 according to this embodiment includes a display panel 110, a cover panel 120, four force sensors 130, and a base unit 150. A display panel 110 is disposed on the base unit 150. The display panel 110 of this embodiment is an LCD (Liquid Crystal Display), but may be an organic EL (Electro-Luminescence) display or the like. The shape of the display area of the display panel 110 of this embodiment is a rectangle.

  Further, a plurality of force sensors 130 are arranged around the display panel 110 on the base part 150. In this embodiment, four force sensors 130 are arranged corresponding to the four vertices of the display panel 110, respectively. The force sensor 130 of this embodiment is a piezoelectric element.

  A cover panel 120 is provided to face the surface of the display panel 110. The touch surface is the surface of the cover panel 120. The shape of the surface of the cover panel 120 of the present embodiment is a rectangle. The four force sensors 130 respectively support the vicinity of the four vertices on the back surface of the cover panel 120. Thereby, there is a predetermined interval between the back surface of the cover panel 120 and the front surface of the display panel 110. The cover panel 120 transmits the display on the display panel 110. The cover panel 120 is realized by glass or plastic, for example.

  A signal conversion unit 500 is further provided on the base unit 150. The signal conversion unit 500 is connected to the four force sensors 130 via signal lines. Note that the signal conversion unit 500 may not be disposed on the base unit 150 as long as it is connected to the force sensor 130. On the base unit 150, a calculation unit 200, an application execution unit 300, and the like may be further provided.

  The four force sensors 130 may support the vicinity of the four vertices on the back surface of the display panel 110, and the front surface of the display panel 110 may be in contact with the back surface of the cover panel 120.

  Further, the shape of the display area of the display panel 110 may be other than a rectangle. Further, the number of force sensors 130 may be other than four. The force sensor 130 may be a capacitor, a strain gauge, or the like.

  In order to remove an unstable operation region due to a minute pressure, a slight pressure is applied to the cover panel 120 in the direction of the base portion 150 as an initial load. In order to apply an initial load, an elastic member such as a spring may be provided between the cover panel 120 and the base portion 150. The output value when the surface of the cover panel 120 is not touched, such as when the cover panel 120 is installed, is measured and stored in the pressing force calculation unit 710 as an initial load.

  The cover panel 120 covers the surface of the display panel 110 and protects the surface of the display panel 110. Furthermore, the surface of the cover panel 120 receives a press (touch) by the user. The four force sensors 130 output an output signal, which is an electrical signal corresponding to the force received from the cover panel 120, to the signal conversion unit 500, thereby continuously measuring the force.

  Hereinafter, the calculation method of a press coordinate is demonstrated.

  FIG. 4 is a plan view showing a coordinate system on the surface of the panel unit 100.

  In this embodiment, the center of the display area of the display panel 110 is the origin, and the surface of the display panel 110 is the XY plane. Of the four force sensors 130, the force sensor 130 arranged in the first quadrant of the XY plane is set as S1, the force sensor 130 arranged in the second quadrant is set as S2, and the force sensor 130 arranged in the third quadrant. Is S3, and the force sensor 130 arranged in the fourth quadrant is S4. In addition, measurement values obtained from the force sensors S1, S2, S3, and S4 are F1, F2, F3, and F4, respectively.

  Here, the distance on the surface of the panel unit 100 is defined in units of pixels in the display panel 110. The size of the display area of the display panel 110 in the X direction is Wd, and the size of the display area in the Y direction is Hd. In this embodiment, Wd is 320 and Hd is 240. Further, the distance between the two force sensors 130 adjacent in the X direction (the distance between S1 and S2, the distance between S3 and S4) is Ws, and the distance between the two force sensors 130 adjacent in the Y direction. Let Hs be the distance (distance between S1 and S4, distance between S2 and S3). In this example, Ws is 422 and Hs is 266. Furthermore, if the distance in the X direction from the origin to the force sensor 130 is Xs, Xs is Ws / 2, and if the distance in the Y direction from the origin to the force sensor 130 is Ys, Ys is Hs / 2. In this embodiment, Xs is 211 and Ys is 133.

  In the pressing coordinate calculation method, the pressing coordinate calculation unit 720 is based on the coordinates of the force sensors S1, S2, S3, and S4 represented by Xs and Ys, the measured values F1, F2, F3, and F4, and the pressing force Fs. The press coordinates PX and PY are calculated using the following formula.

  Hereinafter, the correction area will be described.

  The above-described calculation method of the pressed coordinates is based on an ideal state where the cover panel 120 is a completely rigid body. However, in reality, the output of the force sensor 130 is affected by the bending of the cover panel 120 due to pressing, the absorption of force by the cover panel 120, the load due to how the cover panel 120 is placed, and the like. When the pressed coordinates are the corners of the display area, the variation in the influence of the four force sensors 130 increases, and the accuracy of the pressed coordinates decreases. On the other hand, the closer the pressed coordinate is to the center of the display area, the smaller the variation in the influence of the four force sensors 130, and the higher the accuracy of the pressed coordinate. Therefore, by determining different correction coefficients for the area where the accuracy of the press coordinates is low and the area where the press coordinates are high, the press coordinates can be accurately corrected over the entire display area. The touch panel of the present embodiment divides the display area into a plurality of correction areas corresponding to the accuracy of the press coordinates, and corrects the press coordinates using a correction coefficient for each correction area.

  FIG. 5 is a plan view showing the correction area.

  Here, the number of correction areas is L, the correction area number is j, and the correction area corresponding to the subscript j is ARj. The number of reference coordinates defined in the correction area is N, the reference coordinate number is i, and the reference coordinates corresponding to the subscripts j and i are PRji. The correction coefficient calculation unit 810 stores the reference coordinates PRji. The pressed coordinate correction unit 820 stores a correction area ARj.

  In this embodiment, L is 2, and correction areas AR1 and AR2 are defined in the display area. The outer periphery of the correction area AR1 is the outer periphery of the display area. The boundary between the correction area AR1 and the correction area AR2 is a rectangle smaller than the outer periphery of the display area, and is a rectangle that is concentric and similar to the display area. The correction area AR2 is inside this boundary. The correction area AR1 is an area obtained by removing the correction area AR2 from the display area. The size of the correction area AR2 in the X direction is, for example, Wd / 2. The size of the correction area AR2 in the Y direction is, for example, Hd / 2.

  Vertices PR11, PR12, PR13, and PR14 corresponding to the force sensors S1, S2, S3, and S4 in the display area are set as reference coordinates of the correction area AR1. The vertices PR21, PR22, PR23, and PR24 corresponding to the reference coordinates PR11, PR12, PR13, and PR14 of the correction area AR1 are set as the reference coordinates of the correction area AR2. The reference coordinates may not be the vertexes of the correction area boundary. For example, the four reference coordinates corresponding to one correction area may be rectangular vertices concentric with the display area in the correction area.

  Hereinafter, the correction coefficient calculation process will be described.

  The calculation unit 200 corrects when receiving an instruction to set a low load area from the user, when a predetermined period has elapsed since the setting of the low load area, when the touch panel is shipped, or when the touch panel is inspected. Coefficient calculation processing is executed. The low load region is a range of pressing force in which an error in pressing coordinates becomes large. The low load region is defined by a low load lower limit threshold indicating a lower limit and a low load upper limit threshold indicating an upper limit. The low load lower limit threshold and the low load upper limit threshold may be input from the user to the calculation unit 200. The correction coefficient calculation unit 810 stores a reference pressing force that is a reference pressing force in the low load region. Here, the reference pressing force number is M, the reference pressing force number is k, and the reference pressing force corresponding to the subscript k is FRk. For example, the low load lower limit threshold is set to 5 [g], the low load upper limit threshold is set to 25 [g], the reference pressing force number M is set to 5, and the reference pressing forces FR1, FR2, FR3, FR4, FR5 are set to 5, 10, 15, 20, 25 [g]. In this case, the interval between adjacent reference pressing forces is 5 [g]. The reference pressing force may be input from the user to the calculation unit 200.

  In the correction coefficient calculation process, a correction coefficient for correcting the pressed coordinate is calculated. Further, the calculation unit 200 calculates a correction coefficient Bjk corresponding to the correction area ARj and the reference pressing force FRk. The pressed coordinate correction unit 820 stores correction coefficient information indicating the relationship between the subscripts j and k and the correction coefficient Bjk. The correction coefficient information may be a function for interpolating the correction coefficient Bjk or a coefficient that defines the function.

  FIG. 6 is a flowchart showing the correction coefficient calculation process.

  Here, the correction area is ARj, the reference coordinate number set in the correction area ARj is N, the reference coordinate number is i, the reference pressing force number preset in the low load area is M, and the reference pressing force Let k be the number of. Thus, the reference coordinates corresponding to j and i are represented by PRji, and the reference pressing force corresponding to k is represented by FRk.

  First, the correction coefficient calculation unit 810 sets the value of j to 1 (S100). Thereafter, the correction coefficient calculation unit 810 sets the value of i to 1 (S110). Thereafter, the correction coefficient calculation unit 810 uses the display control unit 410 to select the reference coordinate PRji as the specific coordinate and display a mark on the specific coordinate of the display panel 110. Further, using the display control unit 410, the correction coefficient calculation unit 810 displays a message for causing the user to press this mark on the display panel 110 (S120). This message instructs the user to change the pressing force while pressing the mark. Thereafter, the correction coefficient calculation unit 810 sets the value of k to 1 (S130).

  The pressing force calculation unit 710 obtains output values G1, G2, G3, and G4 corresponding to the four force sensors 130 from the signal conversion unit 500, and the measured values F1 and F2 based on G1, G2, G3, and G4. , F3, and F4 are calculated, and a pressing force Fs that is the sum of F1, F2, F3, and F4 is calculated (S210). Here, the pressing force calculation unit 710 stores in advance initial loads Fw1, Fw2, Fw3, and Fw4 corresponding to the four force sensors 130, and G1, G2, G3, and G4 to Fw1, Fw2, Fw3, and Fw4, respectively. By subtracting, F1, F2, F3, and F4 are calculated. The pressing force Fs indicates a force that presses the surface of the cover panel 120.

  Thereafter, the correction coefficient calculation unit 810 determines whether the difference between Fs and the reference pressing force FRk is equal to or less than a predetermined margin ΔFM (S240). For example, the correction coefficient calculation unit 810 defines the reference pressing force range by a pressing force lower limit threshold obtained by subtracting ΔFM from FRk and a pressing force upper limit threshold obtained by adding ΔFM to FRk. ΔFM is smaller than the interval between adjacent reference pressing forces. In this case, the correction coefficient calculation unit 810 determines that Fs is within the reference pressing force range when Fs is not less than the pressing force lower limit threshold and not more than the pressing force upper limit threshold. Thereby, the correction coefficient calculation unit 810 can select a measurement value when the reference coordinate PRji is pressed with the reference pressing force FRk from the measurement values obtained continuously.

  When it is determined that Fs is not within the reference pressing force range (S240: NO), the correction coefficient calculation unit 810 shifts the process to S210. When it is determined that Fs is within the reference pressing force range (S240: YES), the pressing coordinate calculation unit 720 calculates the pressing coordinates PMjik that are the coordinates of the touched point in response to the instruction of the reference coordinates PRji. (S510). A method for calculating the press coordinates PMjik will be described later.

  Thereafter, the correction coefficient calculation unit 810 adds 1 to k (S610), and determines whether k is equal to or less than M (S620). When it is determined that k is equal to or less than M (S620: YES), the correction coefficient calculation unit 810 shifts the process to S210. When it is determined that k is not M or less (S620: NO), the correction coefficient calculation unit 810 adds 1 to i (S640), and determines whether i is N or less (S650). When it is determined that i is N or less (S650: YES), the correction coefficient calculation unit 810 shifts the process to S120. When it is determined that i is not N or less (S650: NO), the correction coefficient calculation unit 810 sets the value of k to 1 (S710), and performs a correction coefficient for projective conversion of the pressed coordinate PMjik to the reference coordinate PRji. Bjk is calculated (S720). A method for calculating the correction coefficient will be described later.

  Thereafter, the correction coefficient calculation unit 810 adds 1 to k (S730), and determines whether k is equal to or less than M (S740). When it is determined that k is equal to or less than M (S740: YES), the correction coefficient calculation unit 810 shifts the process to S720. When it is determined that k is not M or less (S740: NO), the correction coefficient calculation unit 810 adds 1 to j (S750), and determines whether j is L or less (S760). When it is determined that j is L or less (S760: YES), the correction coefficient calculation unit 810 shifts the process to S110. When it is determined that j is not less than or equal to L (S760: NO), the correction coefficient calculation unit 810 ends this flow.

  The above is the correction coefficient calculation process. According to this process, it is possible to calculate the pressed coordinate PMjik when the reference coordinate PRji is pressed with the reference pressing force FRk. Further, the correction coefficient Bjk corresponding to the correction area ARj and the reference pressing force FRk can be calculated from the pressing coordinate PMjik and the reference coordinate PRji. The user can press the reference coordinate PRji, and the pressing force Fs near the reference pressing force FRk can be detected while the user fluctuates the pressing force to the reference coordinate PRji.

  Note that the correction coefficient calculation unit 810 may calculate a correction coefficient corresponding to the reference pressing force range including Fs when it is determined that the pressing force Fs is included in any of the plurality of reference pressing force ranges. When the pressing force Fs near the reference pressing force FRk cannot be detected, the correction coefficient calculation unit 810 may display an instruction of the pressing force on the display panel 110.

  FIG. 7 is a plan view showing display of reference coordinates.

  In S120 described above, the correction coefficient calculation unit 810 causes the display panel 110 to display the mark 610 indicating the pressed position. This figure shows a case where the reference coordinate PR21 is selected as the specific coordinate and the display panel 110 displays a mark 610 indicating the specific coordinate. Thereby, a user can be made to press a specific coordinate.

  FIG. 8 is a plan view showing reference coordinates and pressing coordinates.

  In S510 described above, the press coordinate calculation unit 720 calculates the press coordinates. This figure shows a case where the pressing coordinate calculation unit 720 detects a pressing force of 5 g which is the reference pressing force FR1 in response to each pressing instruction of the reference coordinates PR21, PR22, PR23, and PR24. In this case, the press coordinates PM211, PM221, PM231, and PM241 are calculated corresponding to the press instructions of the reference coordinates PR21, PR22, PR23, and PR24, respectively. In the example of this figure, the quadrangle having the pressed coordinates PM211, PM221, PM231, and PM241 as vertices ideally matches the quadrangle having the reference coordinates PR21, PR22, PR23, and PR24 as vertices, but actually the reference coordinates PR21, Since it exists inside the quadrangle having PR22, PR23, and PR24 as vertices, correction is required. In S720, the correction coefficient calculation unit 810 calculates correction coefficients for converting the pressed coordinates PM211, PM221, PM231, and PM241 into the reference coordinates PR21, PR22, PR23, and PR24, respectively.

  Hereinafter, a method for calculating the correction coefficient will be described.

  The correction coefficient Bjk is a coefficient for projective transformation of the pressed coordinates to the reference coordinates. Here, when the pressed coordinates are (X1, Y1) and the reference coordinates are (X2, Y2), the relationship is expressed by the following equation, for example.

X2 = (BAjk × X1 + BBjk × Y1 + BCjk)
/ (BGjk × X1 + BHjk × Y1 + 1)
Y2 = (BDjk × X1 + BEjk × Y1 + BFjk)
/ (BGjk × X1 + BHjk × Y1 + 1) (E2)

  The correction coefficient Bjk includes coefficients BAjk, BBjk, BCjk, BDjk, BEjk, BFjk, BGjk, and BHjk. By substituting the corresponding combination of the four pressed coordinates PMj1, PMj2, PMj3, PMj4 and the four reference coordinates PRj1, PRj2, PRj3, PRj4 into the expression E2 for ARj and FRk, eight pieces are obtained. The coefficients BAjk, BBjk, BCjk, BDjk, BEjk, BFjk, BGjk, BHjk, which are unknown numbers, can be calculated.

  Hereinafter, the input detection process will be described.

  The arithmetic unit 200 executes an input detection process for detecting an input based on an output from the force sensor 130 every predetermined input detection period after the correction coefficient calculation process.

  FIG. 9 is a flowchart showing the input detection process.

  The pressing force calculation unit 710 calculates the pressing force Fs by the same process as S210 of the correction coefficient calculation process. The pressing coordinate correction unit 820 determines whether or not the pressing force Fs is greater than or equal to a preset low load lower limit threshold (S310).

  When it determines with Fs not being more than a low load lower limit threshold value (S310: NO), the press coordinate correction | amendment part 820 transfers a process to S210. When it is determined that Fs is equal to or greater than the low load lower limit threshold (S310: YES), the press coordinate calculation unit 720 calculates the press coordinate P in the same manner as S510 of the correction coefficient calculation process (S810). Thereafter, the pressed coordinate correction unit 820 determines whether or not Fs is equal to or higher than a preset low load upper limit threshold (S820). When it is determined that Fs is equal to or greater than the low load upper limit threshold (S820: YES), the pressed coordinate correction unit 820 ends this flow. Thereby, the pressed coordinate correction unit 820 outputs the pressed coordinate P to the application execution unit 300. When it is determined that Fs is not equal to or higher than the low load upper limit threshold (S820: NO), the pressing coordinate correction unit 820 selects a correction coefficient corresponding to the pressing coordinate P and the pressing force Fs (S830). Here, the pressing coordinate correction unit 820 selects the correction area ARj including the pressing coordinate P from the plurality of correction areas, and selects the reference pressing force FRk closest to Fs from the plurality of reference pressing forces. Further, the pressed coordinate correction unit 820 selects a correction coefficient Bjk corresponding to the selected j and k based on the correction coefficient information.

  The pressed coordinate correction unit 820 corrects the pressed coordinate P by projective conversion from the pressed coordinate P to the corrected pressed coordinate PC using the selected correction coefficient Bjk (S840), and ends this flow. Here, the pressed coordinate correcting unit 820 calculates the corrected pressed coordinate PC with the pressed coordinate P as (X1, X2) and the corrected pressed coordinate PC as (X2, Y2) in the above-described equation E2. Thereby, the pressed coordinate correction unit 820 outputs the corrected pressed coordinate PC as the pressed coordinate P to the application execution unit 300.

  The above is the input detection process. According to this process, when the pressing force is in the low load region, it is possible to select the correction coefficient according to the pressing coordinate and the pressing force, and to correct the pressing coordinate using the selected correction coefficient. Thereby, the calculation accuracy of the pressing coordinates when the pressing force is in the low load region can be improved.

  The pressing coordinate correction unit 820 may calculate a correction coefficient corresponding to Fs by interpolating two correction coefficients corresponding to two adjacent reference pressing forces according to the pressing force Fs.

  FIG. 10 is a plan view showing a modification of the correction area.

  The number of correction areas may be three or more. For example, in the display area of the display panel 110, three rectangles that are concentric with, similar to, and different in size from the rectangle of the display area are defined as boundaries, and the display area is divided by the three boundaries, and the divided 4 These areas may be the correction areas AR1, AR2, AR3, AR4. Note that the shape of the boundary of the correction area may be another shape such as a triangle, a diamond, or a circle. Further, the polygonal shape with the reference coordinates at the apex may be different from the shape of the boundary of the correction area.

  According to the present embodiment, by correcting the pressing coordinates using the correction coefficient corresponding to the position in the display area and the pressing force, the accuracy of the pressing coordinates when the pressing force is in the low load area is improved. Can do. Thereby, the touch panel of a present Example can utilize the press coordinate with respect to the pressing force of the wide range compared with the past.

  In addition, the user is instructed to change the pressing force while pressing the reference coordinate, and by calculating the pressing coordinate using the measured value when the measured pressing force is close to the reference pressing force, It is possible to calculate a correction coefficient when the coordinates are pressed with the reference pressing force.

  Note that the initial load may not be applied to the cover panel 120. When an initial load is applied, even if it is necessary to change the correction coefficient due to a change with time of the elastic member, the correction coefficient can be calculated by a simple operation by the user.

  Hereinafter, modified examples in which the present invention is applied to a touchpad will be described.

  The touchpad of the modification does not require the display panel 110 and the display control unit 410 among the elements of the touch panel of the above-described embodiment. Further, the correction coefficient calculation unit 810 does not execute the mark display in S120. For example, a mark is printed at a position corresponding to each of a plurality of reference coordinates on the surface of the cover panel 120. The correction coefficient calculation unit 810 selects one of a plurality of reference coordinates, and another display device displays a message instructing the pressing of the mark corresponding to the selected reference coordinates and the variation of the pressing force. The mark may be pressed by the user. The touchpad according to the modified example can obtain the same effects as those of the touch panel according to the above-described embodiment by such a configuration.

  The present invention is not limited to the above-described embodiment. A person skilled in the art can make various additions and changes within the scope of the present invention.

  The technical terms described in the above embodiments will be described. The cover panel 120 or the like may be a flat plate portion. Correction coefficients or the like may be used as correction information. The display panel 110 or the like may be a display unit. A low load region or the like may be set as a predetermined range. The correction area or the like may be a pressed coordinate area. A mark 610, a message, or the like may be used as the instruction information.

  DESCRIPTION OF SYMBOLS 100: Panel part 110: Display panel 120: Cover panel 130: Force sensor 150: Base part 200: Calculation part 300: Application execution part 300: Calculation part 300: Application execution part 410: Display Control unit, 500: signal conversion unit, 510: A / D conversion unit, 610: mark, 710: pressing force calculation unit, 720: pressing coordinate calculation unit, 810: correction coefficient calculation unit, 820: pressing coordinate correction unit

Claims (13)

A flat plate part;
A plurality of force sensors that are respectively disposed at a plurality of positions of the flat plate portion, and detect a force received from the flat plate portion;
A plurality of correction information for correcting the pressing coordinates is stored in association with the pressing force indicating the pressing force on the surface of the flat plate portion and the pressing coordinates indicating the position of the pressing, and the plurality of force sensors A first pressing force is detected based on the output, a first pressing coordinate is calculated based on the outputs of the plurality of force sensors and the plurality of positions, and the first pressing coordinate is calculated based on the first pressing force and the first pressing coordinate. A calculation unit that selects first correction information from a plurality of correction information, and corrects the first press coordinates using the first correction information;
A touch input device comprising: Including a display area for displaying a screen based on information from the calculation unit, and further comprising a display unit covered with the flat plate part,
The flat plate portion transmits the display,
The arithmetic unit stores a plurality of reference coordinates in the display area, and displays instruction information for instructing the user to press the specific coordinates for the specific coordinates that are each of the plurality of reference coordinates in the display area. And calculating the second pressing force based on the outputs of the plurality of force sensors, and calculating the second pressing coordinates based on the outputs of the plurality of force sensors and the plurality of positions. A plurality of second press coordinates corresponding to the plurality of second press coordinates, a second correction information for converting the plurality of second press coordinates to the plurality of reference coordinates, respectively, and a second correction information for the plurality of second press coordinates. Store as one of the correction information,
The touch input device according to claim 1. The second correction information is a coefficient of projective transformation from the plurality of second press coordinates to the plurality of reference coordinates.
The touch input device according to claim 2. When the first pressing force is within a predetermined range, the calculation unit is configured to select from among the plurality of correction information based on the first pressing force and the first pressing coordinates. Selecting first correction information;
The touch input device according to claim 3. Each of the plurality of correction information is associated with one of a plurality of predetermined press coordinate areas in the surface of the flat plate portion,
The calculation unit selects a first press coordinate area including the first press coordinate from the plurality of press coordinate areas, and corrects the correction corresponding to the first press coordinate area from the plurality of correction information. Selecting information as the first correction information;
The touch input device according to claim 4. Each of the plurality of correction information is associated with one of a plurality of predetermined reference pressing forces,
The calculation unit selects a first reference pressing force closest to the first pressing force from the plurality of reference pressing forces, and corresponds to the first reference pressing force from the plurality of correction information. Selecting correction information as the first correction information;
The touch input device according to claim 5. When the difference between the specific pressing force, which is one of the plurality of reference pressing forces, and the second pressing force is smaller than a predetermined margin, the calculation unit uses the second correction information as the specific pressing force. Store in association,
The touch input device according to claim 6. The shape of the display area is a rectangle,
The boundaries of the plurality of pressed coordinate areas are rectangles concentric with the display area,
The touch input device according to claim 5. The plurality of reference coordinates are four reference coordinates.
The touch input device according to claim 2. The instruction information instructs to change a force for pressing the specific coordinates.
The touch input device according to claim 2. The flat plate portion includes a mark arranged at a position corresponding to a plurality of reference coordinates on the surface,
The calculation unit stores the plurality of reference coordinates, calculates a second pressing force based on outputs of the plurality of force sensors for specific coordinates that are each of the plurality of reference coordinates, and outputs the plurality of force By calculating the second pressing coordinates based on the output of the sensor and the plurality of positions, a plurality of second pressing coordinates respectively corresponding to the plurality of reference coordinates are calculated, and the plurality of second pressing coordinates are set to the plurality of the plurality of second pressing coordinates. Calculating second correction information for conversion to the respective reference coordinates, and storing the second correction information as one of the plurality of correction information.
The touch input device according to claim 1. In association with the pressing force indicating the pressing force on the surface of the flat plate portion and the pressing coordinates indicating the position of the pressing, a plurality of correction information for correcting the pressing coordinates,
The first pressing force is detected based on the outputs of the plurality of force sensors, using a plurality of force sensors that are respectively disposed at a plurality of positions of the flat plate portion, and detecting a force received from the flat plate portion,
Calculating first pressing coordinates based on the outputs of the plurality of force sensors and the plurality of positions;
Selecting first correction information from the plurality of correction information based on the first pressing force and the first pressing coordinate, and correcting the first pressing coordinate using the first correction information;
A touch input correction method comprising: In association with the pressing force indicating the pressing force on the surface of the flat plate portion and the pressing coordinates indicating the position of the pressing, a plurality of correction information for correcting the pressing coordinates,
The first pressing force is detected based on the outputs of the plurality of force sensors, using a plurality of force sensors that are respectively disposed at a plurality of positions of the flat plate portion, and detecting a force received from the flat plate portion,
Calculating first pressing coordinates based on the outputs of the plurality of force sensors and the plurality of positions;
Selecting first correction information from the plurality of correction information based on the first pressing force and the first pressing coordinate, and correcting the first pressing coordinate using the first correction information;
A computer program that causes a computer to execute.

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