JP2014235477A - Touch input device, input detection method, and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine whether or not detection results obtained by a force sensor are attributable to pressing force onto a touch surface.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 200 that individually computes a plurality of measured values indicating force on the basis of output of the plurality of force sensors, that computes pressing force indicating force of pressure on the basis of the plurality of measured values under the assumption that the plurality of measured values are attributable to pressing force onto a surface of a flat plane part; that computes a pressing coordinate indicating a position of the pressure on the surface of the flat plane part on the basis of the plurality of measured values and the plurality of positions; that estimates a plurality of expected measured values that are expected values of the plurality of measured values under the assumption that the pressing force is added to the pressing coordinate; and that determines whether or not the pressing force is attributable to the pressure by comparison between the plurality of measured values and the plurality of expected measured values.

Description

  The present invention relates to a touch input device, an input detection 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.

  Japanese Patent Application Laid-Open No. 2004-228688 describes a technique for removing the influence of mechanical distortion on touch position specification using a calibration parameter.

  Patent Document 3 describes a technique for preventing an input unintended by a user by notifying an operator of a change in pressing load.

JP 2005-78194 A JP 2005-526333 A JP 2011-28663 A

  In a force sensor type touch input device, the output of the force sensor may fluctuate due to mechanical distortion caused by the user holding the housing. Even when the touch surface is touched in a state where such mechanical distortion occurs, there has been a problem that the coordinates of the touch cannot be calculated accurately.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique for determining whether or not the cause of the detection result by the force sensor is a pressure on the touch surface.

  A touch input device according to an aspect of the present invention includes a flat plate portion, a plurality of force sensors that are arranged at a plurality of positions of the flat plate portion, detect a force received from the flat plate portion, and outputs of the plurality of force sensors. A plurality of measured values indicating the force are calculated based on the pressure, and the pressing force is calculated based on the plurality of measured values under the assumption that the cause of the force received by the plurality of force sensors is the pressing of the surface of the flat plate portion. A pressing coordinate indicating a pressing position on the surface of the flat plate portion based on a plurality of measured values and a plurality of positions, and calculating a plurality of pressures under the assumption that the pressing force is applied to the pressing coordinates. A calculation unit that estimates a plurality of measurement expected values that are expected values of the measurement value, and compares the plurality of measurement values and the plurality of measurement expected values to determine whether the cause of the pressing force is a pressure, and Is provided.

  The calculation unit may calculate a plurality of expected measurement values by allocating the pressing force to a plurality of positions based on the pressing coordinates.

  The calculation unit may calculate a difference between the plurality of measured values and the plurality of expected measurement values, and may determine that the cause of the pressing force is a pressure when the magnitude of the difference is smaller than a predetermined difference threshold value.

  When it is determined that the cause of the pressing force is not pressing, the calculation unit may output a predetermined processing instruction.

  The calculation unit stores a plurality of initial loads respectively indicating outputs of the plurality of force sensors in a predetermined state, calculates a plurality of measured values by subtracting the plurality of initial loads from the outputs of the plurality of force sensors, When it is determined that the cause is not pressing, a plurality of initial loads may be changed based on a plurality of measured values.

1 is a block diagram illustrating a configuration of a touch panel according to Embodiment 1. FIG. 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. 3 is a flowchart illustrating input detection processing according to the first embodiment. The top view which shows the coordinate system of the panel part 100 surface. FIG. 4 is a block diagram illustrating a configuration of a touch panel according to a second embodiment. 9 is a flowchart illustrating input detection processing according to the second embodiment. The flowchart which shows an initial load update process. 10 is a flowchart illustrating input detection processing according to the third embodiment.

  When the touch input device of the present embodiment detects a measurement value based on the output of the force sensor, the touch input device assumes that the touch surface has been pressed, calculates the coordinates on the touch surface, and the coordinates By calculating the expected value of the measured value to obtain the result and comparing the detected measured value with the calculated expected value, it is determined whether or not the cause of the detected measured value is the touch surface pressing To do. Thereby, erroneous detection of pressing can be reduced.

  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.

  The touch panel of the present embodiment determines whether or not the cause of the force detected by the force sensor is a press (touch) on the touch surface, and determines that the cause is a press on the touch surface, based on the press. The calculated coordinates are output, and when it is determined that the cause is not the touch surface pressing, the calculated coordinates are not output.

  FIG. 1 is a block diagram illustrating the configuration of the touch panel according to the first 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 an input calculation unit 310 and a measurement expected value calculation unit 330. The input calculation unit 310 acquires an output value from the signal conversion unit 500 at a predetermined measurement cycle, and calculates a measurement value that indicates each variation in the output value. Further, the input calculation unit 310 assumes that the cause of the measurement value is a pressure on the surface of the panel unit 100, and calculates a pressing force indicating a pressing force based on the measurement value. Further, the input calculation unit 310 assumes that the cause of the measurement value is a pressure on the surface of the panel unit 100, and calculates the press coordinates that are the coordinates of the press based on the measurement value and the pressing force. The measurement expectation value calculation unit 330 assumes that the cause of the pressing force is a pressure on the surface of the panel unit 100, and estimates the measurement value based on the pressing force and the pressing coordinates, thereby measuring the expected value of the measurement value. Calculate the expected value. The determination unit 340 determines whether the cause of the pressing force is a pressure on the surface of the panel unit 100 based on the measured value and the expected 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 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 flat plate portion corresponds to the cover panel 120 or the like.

  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 body such as a spring may be provided between the cover panel 120 and the base portion 150. When the cover panel 120 is installed, the output value when the surface of the cover panel 120 is not touched is measured and stored in the input calculation unit 310 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.

  The arithmetic unit 200 performs an input detection process for detecting an input based on an output from the force sensor 130 at every predetermined input detection cycle.

  FIG. 4 is a flowchart illustrating the input detection process according to the first embodiment.

  The input calculation unit 310 stores in advance initial loads Fw1, Fw2, Fw3, and Fw4 corresponding to the four force sensors 130, respectively. When the input detection process is started, the input calculation unit 310 acquires output values G1, G2, G3, and G4 corresponding to the four force sensors 130 from the signal conversion unit 500 (S110), and G1, G2, The measured values F1, F2, F3, and F4 are calculated by subtracting Fw1, Fw2, Fw3, and Fw4 from G3 and G4, respectively (S120). Thereby, the influence of the initial load can be removed from the output value. Thereafter, the input calculation unit 310 calculates a pressing force Fs that is the sum of the measured values F1, F2, F3, and F4 (S130). When it is assumed that the cause of the measured value is the pressure on the surface of the cover panel 120, the pressing force Fs indicates a force that presses the surface of the cover panel 120. Thereafter, the input calculation unit 310 determines whether or not the pressing force is equal to or greater than a predetermined pressing force threshold Fth (S140). Thereby, even if the input calculation part 310 detects the pressing force smaller than a pressing force threshold value, it does not determine with the press having been performed but can reduce misdetection.

  When it is determined that the pressing force is not equal to or greater than the pressing force threshold (S140: NO), the input calculation unit 310 shifts the process to S110. When it is determined that the pressing force is equal to or greater than the pressing force threshold (S140: YES), the input calculation unit 310 assumes that the cause of the measured value is the pressing on the surface of the cover panel 120, and the coordinates of the touched point. The pressed coordinates are calculated (S150). A method for calculating the press coordinates will be described later.

  Thereafter, the expected measurement value calculation unit 330 calculates the expected measurement value, which is the expected value of the measurement value, assuming that the pressing force is applied to the pressed coordinate (S210). A method for calculating the expected measurement value will be described later. The determination unit 340 calculates a difference value between the measurement value and the measurement expected value, and determines whether or not the difference value satisfies a predetermined difference condition (S220). A method for determining the difference value will be described later.

  When it is determined that the difference value satisfies the difference condition (S220: YES), the determination unit 340 recognizes that the cause of the pressing force is the pressure on the surface of the cover panel 120, and the application execution unit 300 determines the pressing coordinates and the pressing force. (S230), and this flow ends. When it is determined that the difference value does not satisfy the difference condition (S220: NO), the determination unit 340 recognizes that the cause of the pressing force is not pressing on the surface of the cover panel 120, and outputs the pressing coordinates and the pressing force. This flow is finished.

  The above is the input detection process. According to this input detection process, is the input measured by the force sensor 130 a normal input due to the pressure on the surface of the cover panel 120 or an abnormal input due to something other than a pressure on the surface of the cover panel 120? Can be distinguished.

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

  FIG. 5 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 calculation method of the pressing coordinates, the input calculation unit 310 is based on the coordinates of the force sensors S1, S2, S3, S4 represented by Xs and Ys, the measured values F1, F2, F3, F4, and the pressing force Fs. The press coordinates PX and PY are calculated using the following formula.

  Hereinafter, a method for calculating the expected measurement value will be described.

  The expected measurement value calculation unit 330 distributes the pressing force Fs to the coordinates of the force sensors S1, S2, S3, and S4 represented by Xs and Ys, thereby measuring corresponding to the force sensors S1, S2, S3, and S4, respectively. Expected values E1, E2, E3, and E4 are calculated. Here, a description will be given using a specific example when (35.000, 52.100, 30.650, 2.250) is obtained as the measurement values (F1, F2, F3, F4). In this case, the pressing force Fs is 120, and the pressing coordinates (PX, PY) are (−80, 60) by the above-described calculating method of the pressing coordinates.

  The expected measurement value calculation unit 330 calculates an expected origin measurement value that is an expected value of the measured value when the origin is pressed with a pressing force. Here, the origin measurement expected values corresponding to the force sensors S1, S2, S3, and S4 are O1, O2, O3, and O4, respectively. The origin measurement expected value is expressed by the following equation.

O1 = O2 = O3 = O4 = Fs / 4
= 120/4 = 30

  Thereafter, the expected measurement value calculation unit 330 calculates the influence TempX by the X coordinate of the pressed coordinate using the following equation.

TempX = PX x O1 / Xs
= -80 x 30/211 = -11.374

  Thereafter, the expected measurement value calculation unit 330 uses the following formula to reflect TempX in the origin measurement expected value, so that the temporary measurement expected values PreE1, PreE2, and PreE3 corresponding to the force sensors S1, S2, S3, and S4, respectively. , PreE4 is calculated.

PreE1 = O1 + TempX
= 30 + (-11.374) = 18.726
PreE2 = O2-TempX
= 30-(-11.374) = 40.374
PreE3 = O3-TempX
= 30-(-11.374) = 40.374
PreE4 = O4 + TempX
= 30 + (-11.374) = 18.726

  Thereafter, the measurement expected value calculation unit 330 calculates the influences TempY1 and TempY2 due to the Y coordinate of the pressed coordinates using the following equation.

TempY1 = PY × PreE1 / Ys
= (60 × 18.726) / 133 = 8.448
TempY2 = PY × PreE2 / Ys
= (60 x 40.374) / 133 = 18.214

  Thereafter, the expected measurement value calculation unit 330 calculates expected measurement values E1, E2, E3, and E4 by reflecting TempY1 and TempY2 in the origin measurement expected value using the following equation.

E1 = PreE1 + TempY1
= 18.726+ (8.448) = 27.174
E2 = PreE2 + TempY2
= 40.374+ (18.214) = 58.588
E3 = PreE3-TempY2
= 40.374-(18.214) = 22.160
E4 = PreE4-TempY1
= 18.726- (8.448) = 10.278

  According to the above calculation method of the expected measurement value, the measured value when the pressing force is applied to the pressing coordinate is estimated by allocating the pressing force Fs to the coordinates of the four force sensors 130 based on the pressing coordinate. can do.

  Hereinafter, a method for determining the expected measurement value will be described.

  The determination unit 340 compares the measured value with the expected measurement value. For example, the determination unit 340 calculates the difference values D1, D2, D3, and D4 by subtracting the corresponding measurement values F1, F2, F3, and F4 from the expected measurement values E1, E2, E3, and E4, respectively. Thereafter, the determination unit 340 calculates a total difference value Ds that is the sum of the difference values D1, D2, D3, and D4. If the cause of the pressing force is a pressing coordinate, each of D1, D2, D3, D4, and Ds approaches zero.

  At this time, the difference condition is that the absolute value of all the difference values is equal to or less than a predetermined difference threshold value, and the absolute value of the total difference value is equal to or less than the predetermined total difference threshold value. The difference threshold and the total difference threshold are sufficiently smaller than the magnitude of the pressing force, for example, 2% of the magnitude of the pressing force. In this specific example, (D1, D2, D3, D4) becomes (−7.826, 6.488, −8.49, 8.028), and Ds becomes −1.8. If the difference threshold value and the total difference threshold value are 2.4, the absolute value of the difference value exceeds the difference threshold value, so the determination unit 340 determines that the difference value does not satisfy the difference condition. The difference condition may be that the absolute values of all the difference values are less than or equal to a predetermined difference threshold value, or that the absolute values of the total difference values are less than or equal to a predetermined total difference threshold value. .

  If only the high-precision force sensor 130 is used for the touch panel, vibrations are transmitted to the force sensor 130 when a person walks near the touch panel or touches a desk on which the touch panel is placed. Detection may occur. According to the present embodiment, the cause of the output of the force sensor 130 is the pressure on the surface of the cover panel 120 or other than the pressure on the surface of the cover panel 120 based on the expected measurement value without providing any special hardware. By determining whether or not, erroneous detection can be prevented.

  The initial load may change due to distortion of the touch panel housing, and correct pressing coordinates may not be obtained. For example, in a state where the touch panel is used while standing or a book or palm is placed on the surface of the cover panel 120, an initial load different from a preset value is applied to the force sensor 130 while the state continues. . Therefore, the pressure on the cover panel 120 surface may not be measured correctly.

  When the touch panel of the present embodiment detects a force other than pressing on the surface of the cover panel 120 and determines that the detected force is stable for a certain period of time, an initial load is calculated based on the detected force. Update.

  In the present embodiment, the difference from the first embodiment will be mainly described.

  FIG. 6 is a block diagram illustrating a configuration of the touch panel according to the second embodiment.

  Compared to the touch panel of the first embodiment, the touch panel of the second embodiment includes a calculation unit 200b instead of the calculation unit 200. Compared with the calculation unit 200, the calculation unit 200 b newly includes an initial load update unit 420. When a force other than pressing on the surface of the cover panel 120 is detected, the initial load update unit 420 updates the initial load based on the force.

  The initial load update unit 420 outputs the output value from the signal conversion unit 500 to the input calculation unit 310 as an initial load when the panel unit 100 is installed or periodically measured and the cover panel 120 is not touched. To do. The input calculation unit 310 stores the initial load. Thereafter, the input calculation unit 310 calculates a measurement value from the output value of the signal conversion unit 500 using the initial load.

  The computing unit 200b performs an input detection process for detecting an input based on an output from the force sensor 130 at every predetermined input detection cycle.

  FIG. 7 is a flowchart illustrating input detection processing according to the second embodiment.

  The calculation unit 200b performs the processes of S110 to S140, as in the input detection process of the first embodiment.

  When it is determined that the pressing force is not equal to or greater than the pressing force threshold (S140: NO), the input calculation unit 310 executes an initial load update process (1) for updating the initial load (S160), and the process proceeds to S110. . The initial load update process (1) will be described later. When it is determined that the pressing force is equal to or greater than the pressing force threshold value (S140: YES), the input calculation unit 310 executes the processing of S150 to S220 as in the input detection processing of the first embodiment.

  When it is determined that the difference value satisfies the difference condition (S220: YES), the determination unit 340 executes the same S230 as in the first embodiment and ends this flow. When it is determined that the difference value does not satisfy the difference condition (S220: NO), the initial load update unit 420 executes an initial load update process (2) similar to the initial load update process (1) (S310), This flow is finished. The initial load update process (2) will be described later.

  FIG. 8 is a flowchart showing the initial load update process.

  The initial load update process is an initial load update process (1) of S160 described above and an initial load update process (2) of S310 described above. The initial load update unit 420 stores two values of N in order to indicate a monitoring period of length of measurement period × N. N used for the initial load update process (2) is larger than N used for the initial load update process (1). That is, the monitoring period of the initial load update process (2) is longer than the monitoring period of the initial load update process (1). The monitoring period of the initial load update process (1) is, for example, 0.5 seconds or less. The monitoring period of the initial load update process (2) is, for example, 1 minute. The input calculation unit 310 stores an initial load Fwi (i = 1, 2, 3, 4).

  The initial load updating unit 420 sets the counter value n to 1 and starts the monitoring period of the measured value Fi (S410). Thereafter, the input calculation unit 310 acquires Fi from the input calculation unit 310 (S420). Here, Fi is a value obtained by subtracting the initial load Fwi from the output value Gi as described above. Thereafter, the initial load update unit 420 determines whether or not Fi satisfies a predetermined change condition (S440). The changing condition is that Fi is stable. For example, the change condition is that any magnitude of Fi is equal to or greater than a predetermined deviation threshold, and the magnitude of fluctuation of Fi during the monitoring period is equal to or less than a predetermined fluctuation amount threshold.

  For example, in S440, the initial load update unit 420 determines whether any absolute value of Fi is greater than or equal to the deviation threshold. When it is determined that the absolute values of all Fi are not greater than or equal to the deviation threshold, the initial load update unit 420 determines that Fi does not satisfy the change condition. When any absolute value of Fi is greater than or equal to the deviation threshold, the initial load update unit 420 determines whether n is 1. When it is determined that n is 1, the initial load update unit 420 stores Fi as a reference value. When it is determined that n is not 1, the initial load update unit 420 calculates the fluctuation amount of Fi from the reference value by subtracting the reference value from Fi, and the absolute value of the fluctuation amount is equal to or less than the fluctuation amount threshold value. It is determined whether or not. When it is determined that the absolute value of the fluctuation amount is not equal to or less than the fluctuation amount threshold value, the initial load update unit 420 determines that Fi does not satisfy the change condition. In addition, when it is determined that the absolute value of the initial load fluctuation amount is equal to or less than the initial load fluctuation threshold, the initial load update unit 420 determines that Fi satisfies the change condition.

  When it is determined that Fi does not satisfy the change condition (S440: NO), the initial load updating unit 420 does not update the initial load and ends this flow. When it is determined that Fi satisfies the change condition (S440: YES), the initial load update unit 420 adds 1 to n (S450), and determines whether n is N or less (S460). Thereby, the initial load update unit 420 can detect that Fi is stable in the monitoring period.

  When it is determined that n is equal to or less than N (S460: YES), the initial load update unit 420 shifts the process to S420. When it is determined that n is not N or less (S460: NO), the initial load update unit 420 calculates the Fwi correction amount ΔFai based on Fi (S510). For example, the initial load updating unit 420 calculates the average of N Fi acquired during the monitoring period as ΔFai.

  The initial load update unit 420 updates Fwi by adding ΔFai to Fwi, outputs the updated Fwi to the input calculation unit 310 (S520), and ends this flow.

  In S440, the initial load update unit 420 may not immediately end the initial load update process when it is determined that Fi does not satisfy the change condition. For example, in S440, the initial load update unit 420 counts the number of nonconformities, which is the number of times that Fi is determined not to satisfy the change condition during the monitoring period, and updates the initial load when the number of nonconformities exceeds a predetermined nonconformity count threshold. The process may be terminated, and the process may proceed to S460 when the number of nonconformities is equal to or less than the nonconformance count threshold. The nonconformity frequency threshold is sufficiently smaller than N, for example, N / 10. Thereby, even if Fi slightly fluctuates during the monitoring period, it can be determined that Fi is stable.

  The above is the initial load update process.

  Since the initial load update process (1) is executed in a state where the pressing force is smaller than the pressing force threshold value, the initial load is updated based on a change in measured value caused by natural distortion of the touch panel housing. Since the initial load update process (2) is executed in a state where the pressing force is equal to or greater than the pressing force threshold value, the initial load is updated based on a change in the measured value due to some force applied to the casing of the touch panel. In the initial load update process (2), the initial load update unit 420 may shorten the monitoring period by ending the monitoring period in response to an input from the user.

  According to the present embodiment, it is possible to detect that the deviation of the measured value is stable and correct the initial load based on the measured value. For example, the touch panel of the present embodiment may be applied to a tablet terminal, the tablet terminal may be leaned against another object, and the back surface of the tablet terminal may be supported by the object. In this case, the cover panel 120 is distorted. When the touch panel of this embodiment is stabilized in a state where the cover panel 120 is distorted, the accuracy of the pressing force and the pressing coordinates can be improved by calculating a new initial load. In addition, the initial load can be updated each time the touch panel support method is changed and stabilized.

  The touch panel of the present embodiment executes a predetermined process when a force other than pressing on the surface of the cover panel 120 is detected.

  In the present embodiment, the difference from the first embodiment will be mainly described.

  The arithmetic unit 200 performs an input detection process for detecting an input based on an output from the force sensor 130 at every predetermined input detection cycle.

  FIG. 9 is a flowchart illustrating input detection processing according to the third embodiment.

  The arithmetic unit 200 executes the processes of S110 to S220 as in the input detection process of the first embodiment.

  When it is determined that the difference value satisfies the difference condition (S220: YES), the determination unit 340 executes the same S230 as in the first embodiment and ends this flow. When it is determined that the difference value does not satisfy the difference condition (S220: NO), the determination unit 340 outputs a predetermined specific processing instruction to the application execution unit 300 (S320), and ends this flow.

  Upon receiving the notification, the application execution unit 300 executes the specific process assigned to the instruction. When the touch panel is an information communication terminal such as a smartphone or a tablet terminal, the specific process is, for example, sleep release, screen scrolling, page turning, and locking. For example, functions such as sleep release, screen scrolling, and page turning can be executed simply by grasping the information communication terminal. Further, when the information communication terminal receives an impact due to dropping, a function such as locking can be executed.

  According to the present embodiment, the user can cause the application execution unit 300 to execute a predetermined process by applying a force other than pressing on the surface of the cover panel 120 to the touch panel without providing a special switch on the touch panel. it can.

  When the present invention is applied to a touch pad, the touch pad 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. The touch pad having such a configuration can obtain the same effect as the touch panel of the above-described embodiment.

  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.

  DESCRIPTION OF SYMBOLS 100: Panel part 110: Display panel 120: Cover panel 130: Force sensor 150: Base part 200, 200b: Operation part 300: Application execution part 310: Input calculation part 330: Expected measurement value calculation 340: Determination unit 410: Display control unit 420: Initial load update unit 500: Signal conversion unit 510: A / D conversion 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 measurement values indicating the force are calculated based on outputs of the plurality of force sensors, respectively, and the plurality of measurements are performed under the assumption that the cause of the plurality of measurement values is a pressure on the surface of the flat plate portion. A pressing force indicating the pressing force is calculated based on the value, a pressing coordinate indicating the pressing position on the surface of the flat plate portion is calculated based on the plurality of measured values and the plurality of positions, and the pressing force is calculated. Calculating a plurality of measurement expectation values that are expected values of the plurality of measurement values under the assumption that is added to the pressed coordinates, and comparing the plurality of measurement values and the plurality of measurement expectation values, A calculation unit that determines whether the cause of the pressing force is the pressing;
A touch input device comprising: The calculation unit calculates the plurality of expected measurement values by allocating the pressing force to the plurality of positions based on the pressing coordinates.
The touch input device according to claim 1. The calculation unit calculates a difference between the plurality of measurement values and the plurality of measurement expected values, and determines that the cause of the pressing force is the pressure when the magnitude of the difference is smaller than a predetermined difference threshold value. To
The touch input device according to claim 2. The calculation unit outputs a predetermined processing instruction when it is determined that the cause of the pressing force is not the pressing,
The touch input device according to claim 1. The arithmetic unit stores a plurality of initial loads respectively indicating outputs of the plurality of force sensors in a predetermined state, and subtracts the plurality of initial loads from the outputs of the plurality of force sensors to obtain the plurality of measured values. Calculating, if it is determined that the cause of the pressing force is not the pressing, changing the plurality of initial loads based on the plurality of measured values,
The touch input device according to claim 1. When it is determined that the cause of the pressing force is not the pressing, the calculation unit determines whether or not the measurement value continuously calculated during the first period of a predetermined length is stable, When it is determined that the measurement values continuously calculated during the first period are stable, the plurality of initial loads are changed based on the measurement values continuously calculated during the first period.
The touch input device according to claim 5. When the pressing force is smaller than a predetermined threshold, the calculation unit determines whether the measurement value continuously calculated during the second period shorter than the first period is stable, and the second period When it is determined that the measurement values continuously calculated during are stable, the plurality of initial loads are changed based on the measurement values continuously calculated during the second period.
The touch input device according to claim 6. When the pressing force is smaller than a predetermined threshold, the calculation unit determines whether or not the measurement value continuously calculated during the third period of a predetermined length is stable, and during the third period When it is determined that the measurement values continuously calculated are stable, the plurality of initial loads are changed based on the measurement values continuously calculated during the third period.
The touch input device according to claim 5. The calculation unit calculates a total of the plurality of measured values as the pressing force, and when the magnitude of the pressing force is larger than a predetermined pressing force threshold, the coordinates of the plurality of force sensors in the flat plate portion and the plurality Based on the measured value of the, to calculate the pressing coordinates,
The touch input device according to claim 1. The surface of the flat plate portion is rectangular,
The plurality of force sensors are four force sensors,
The four force sensors are arranged corresponding to the four vertices on the back surface of the flat plate part,
The touch input device according to claim 1. Including a display area for displaying a screen based on an instruction from the calculation unit, and further comprising a display unit covered with the flat plate part,
The flat plate portion transmits the display,
The pressing coordinates are represented by coordinates on the display area.
The touch input device according to claim 1. A plurality of force sensors, which are arranged at a plurality of positions of the flat plate portion, respectively, detect a force received from the flat plate portion, and calculate a plurality of measured values indicating the force based on outputs of the plurality of force sensors, respectively. And
Under the assumption that the cause of the plurality of measured values is a pressure on the surface of the flat plate portion, a pressing force indicating the pressing force is calculated based on the plurality of measured values, and the plurality of measured values and the Calculate the pressing coordinates indicating the position of the pressing on the surface of the flat plate portion based on a plurality of positions,
Calculating a plurality of expected measurement values that are expected values of the plurality of measured values under the assumption that the pressing force is applied to the pressing coordinates;
By comparing the plurality of measured values and the plurality of expected measurement values, it is determined whether or not the cause of the pressing force is the pressing.
An input detection method comprising: A plurality of force sensors, which are arranged at a plurality of positions of the flat plate portion, respectively, detect a force received from the flat plate portion, and calculate a plurality of measured values indicating the force based on outputs of the plurality of force sensors, respectively. And
Under the assumption that the cause of the plurality of measured values is a pressure on the surface of the flat plate portion, a pressing force indicating the pressing force is calculated based on the plurality of measured values, and the plurality of measured values and the Calculate the pressing coordinates indicating the position of the pressing on the surface of the flat plate portion based on a plurality of positions,
Calculating a plurality of expected measurement values that are expected values of the plurality of measured values under the assumption that the pressing force is applied to the pressing coordinates;
By comparing the plurality of measured values and the plurality of expected measurement values, it is determined whether or not the cause of the pressing force is the pressing.
A computer program that causes a computer to execute.

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