Electrostatic coordinate input device, and operation determination method for electrostatic coordinate input device

Abstract

Provided are: an electrostatic coordinate input device with which operations such as contacting or approaching can be determined with high accuracy according to the distance from an indicator, and erroneous operations can be suppressed; and an electrostatic coordinate input device operation determination method.　The electrostatic coordinate input device comprises: an operation surface; a plurality of sensor electrodes arranged on a back side of the operation surface; a measurement circuit that measures an electrostatic capacitance of each of the plurality of sensor electrodes; and a calculation unit that calculates the position of an indicator on the basis of a plurality of electrostatic capacitances measured by the measurement circuit. The calculation unit calculates a maximum electrostatic capacitance between the indicator and the sensor electrodes on the basis of the plurality of electrostatic capacitances, and sets, on the basis of the maximum electrostatic capacitance, a non-pointing determination threshold used to determine a non-pointing operation which is not a pointing operation of the indicator. If the number of electrostatic capacitances exceeding the non-pointing determination threshold among the plurality of electrostatic capacitances exceeds a determination number threshold, the operation of the indicator is determined to be the non-pointing operation.

Description

Technical Field

[0001] The present disclosure relates to an electrostatic coordinate input device and an operation determination method in the electrostatic coordinate input device.

Background Art

[0002] Conventionally, there is a sensor controller connected to a matrix electrode including M first electrodes extending in a first direction and N second electrodes extending in a second direction. The sensor controller supplies a predetermined signal to the M first electrodes, and detects a finger touch area indicating an area where a finger is touching by a predetermined signal detected by the N second electrodes in a finger touch detection step, and uses at least a part of the M first electrodes and at least a part of the N second electrodes to detect an undetected stylus and derive the position coordinates of the stylus in a full range scan step. Further, the sensor controller uses a number of the first electrodes less than the number of the first electrodes used in the full range scan step and a number of the second electrodes less than the number of the second electrodes used in the full range scan step to derive the position coordinates of a detected stylus in a sector scan step, and determines whether the position coordinates derived in the sector scan step are included in any of the finger touch areas detected in the finger touch detection step in a determination step, and executes an invalidation step of invalidating the position coordinates determined to be included in the determination step. The sensor controller further includes a palm rejection step of invalidating the one or more finger touch areas detected in the finger touch detection step by palm rejection processing based on the area size. The sensor controller performs a process of determining whether the position coordinates derived in the sector scan step are included in any of the finger touch areas detected in the finger touch detection step in the determination step before executing the palm rejection step (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-168217 [Overview of the project] [Problems that the invention aims to solve]

[0004] Incidentally, conventional sensor controllers (control units for input devices) do not change the threshold for determining whether or not a touch (contact) has occurred depending on the distance between the operating surface and the indicator object such as a hand. Therefore, it is difficult to accurately determine whether or not an operation such as contact or proximity has occurred depending on the distance between the operating surface and the indicator object such as a hand, and there is a risk of erroneous operation.

[0005] Therefore, the objective is to provide an electrostatic coordinate input device that can accurately determine whether or not an operation such as contact or proximity has occurred depending on the distance to the indicator, thereby suppressing erroneous operations, and an operation determination method for the electrostatic coordinate input device. [Means for solving the problem]

[0006] The electrostatic coordinate input device of the embodiment of the present disclosure comprises an operating surface, a plurality of sensor electrodes arranged on the back side of the operating surface, a measurement circuit for measuring the capacitance of each of the plurality of sensor electrodes, and a calculation unit for calculating the position of an indicator based on the plurality of capacitances measured by the measurement circuit. The calculation unit calculates the maximum capacitance between the indicator and the sensor electrodes based on the plurality of capacitances, sets a non-pointing determination threshold used to determine a non-pointing operation of the indicator based on the maximum capacitance, and determines that the operation of the indicator is a non-pointing operation if the number of capacitances among the plurality of capacitances that exceeds the non-pointing determination threshold exceeds a determination number threshold. [Effects of the Invention]

[0007] This invention provides an electrostatic coordinate input device that can accurately determine whether or not an operation such as contact or proximity has occurred based on the distance to the indicator, thereby suppressing erroneous operations, and a method for determining operations in an electrostatic coordinate input device. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows an example of the configuration of an electrostatic coordinate input device according to the embodiment. [Figure 2] This figure shows an example of the configuration of an electrostatic coordinate input device according to the embodiment. [Figure 3] This figure shows an example of the configuration of the electrostatic sensor and control device of the electrostatic coordinate input device according to the embodiment. [Figure 4A] This diagram illustrates examples of pointing and non-pointing operations. [Figure 4B] This diagram illustrates examples of pointing and non-pointing operations. [Figure 4C] This diagram illustrates examples of pointing and non-pointing operations. [Figure 5] This figure shows an example of a threshold for determining distance status. [Figure 6] This figure summarizes the distance state determined by the electrostatic coordinate input device of the embodiment, showing the relationship between the maximum capacitance and the previous distance state. [Figure 7] This diagram shows a flowchart illustrating the process performed by the control device of the electrostatic coordinate input device according to the embodiment. [Figure 8] This flowchart shows an example of distance state determination processing. [Figure 9] This figure shows an example of a table data for thresholds used in the non-pointing operation detection process. [Figure 10] This is a flowchart showing the process for determining whether an action is not a pointing gesture. [Figure 11A] This figure shows an example of the capacitance distribution detected by an electrostatic sensor. [Figure 11B] This figure shows an example of the capacitance distribution detected by an electrostatic sensor. [Figure 11C] This figure shows an example of the capacitance distribution detected by an electrostatic sensor. [Figure 11D] It is a diagram showing an example of the capacitance distribution detected by the electrostatic sensor. [Figure 12A] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 12B] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 12C] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 12D] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 12E] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13A] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13B] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13C] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13D] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13E] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 13F] It is a diagram showing an operation example of the electrostatic coordinate input device of the embodiment. [Figure 14A] It is a diagram showing a modified example of the table data of the threshold value used for the non-finger-pointing operation determination process. [Figure 14B] It is a diagram showing a modified example of the table data of the threshold value used for the non-finger-pointing operation determination process. [Figure 14C] It is a diagram showing a modified example of the table data of the threshold value used for the non-finger-pointing operation determination process. [Figure 15] It is a flowchart showing a modified example of the non-finger-pointing operation determination process.

Embodiments for Carrying Out the Invention

[0009] The following describes embodiments applying the electrostatic coordinate input device and the operation determination method in the electrostatic coordinate input device described herein.

[0010] <Embodiment> Figures 1 and 2 show an example of the configuration of the electrostatic coordinate input device 100 according to the embodiment. Figure 1 shows the electrostatic coordinate input device 100 in operation and the display device 110 displaying an input image. When the display device 110 is displaying an input image, the electrostatic coordinate input device 100 is in input mode. Input mode is a mode in which operation input can be made to the electrostatic coordinate input device 100. Figure 2 shows the electrostatic coordinate input device 100 in standby mode and the display device 110 displaying a standby image. When the display device 110 is displaying a standby image, the electrostatic coordinate input device 100 is in power-saving mode. In standby mode, the display device 110 is displayed entirely in gray and consumes little power. Figure 3 shows an example of the configuration of the electrostatic sensor 120 and control device 130 of the electrostatic coordinate input device 100. The display device 110 is an example of a display unit, the electrostatic sensor 120 is an example of a detection unit, and the control device 130 is an example of a control unit.

[0011] The following explains the XYZ coordinate system. The directions parallel to the X-axis (X direction), the directions parallel to the Y-axis (Y direction), and the directions parallel to the Z-axis (Z direction) are mutually orthogonal. Furthermore, in the following explanation, the -Z direction is described as the direction approaching the electrostatic sensor 120, and the +Z direction is described as the direction away from the electrostatic sensor 120. Plane view refers to viewing from the XY plane. Also, in the following explanation, the length, width, thickness, etc. of each part may be exaggerated to make the configuration easier to understand.

[0012] The electrostatic coordinate input device 100 may be, for example, a tablet-type input device or the input section of an ATM (Automatic Teller Machine) that is placed in a store or facility and used by an unspecified number of users. It may also be the input section of a cooking appliance that needs to be kept clean. Furthermore, the electrostatic coordinate input device 100 may be a tablet computer, smartphone, game console, etc., used by an individual.

[0013] <Overall configuration of electrostatic coordinate input device 100> The electrostatic coordinate input device 100 includes a housing 101, a top panel 105, a display device 110, an electrostatic sensor 120, and a control device 130. Although the control device 130 (see Figure 3) is omitted in Figures 1 and 2, the control device 130 is, for example, located inside the housing 101, below the display device 110 and the electrostatic sensor 120. The electrostatic coordinate input device 100 includes the electrostatic sensor 120 and the control device 130 shown in Figure 3.

[0014] <Chassis 101 and top panel 105> The housing 101 is a case made of resin or metal, etc., that houses the display device 110, the electrostatic sensor 120, and the control device 130. The display device 110 is, for example, positioned below the transparent electrostatic sensor 120 and is visible through the operating surface 105A, which is the upper surface of the transparent top panel 105 provided in an opening at the top of the housing 101.

[0015] <Types of operating methods for the electrostatic coordinate input device 100> The electrostatic coordinate input device 100 can be operated in both states: when the user's hand or other pointing object is not in contact with the operating surface 105A, and when the user's hand or other pointing object is in contact with the operating surface 105A.

[0016] There are four types of operation methods for the electrostatic coordinate input device 100: proximity operation, selection operation, confirmation operation, and contact operation. Of the four operation methods, proximity operation, selection operation, and confirmation operation are performed when the indicator, such as a hand, is not in contact with the operating surface 105A. Contact operation is performed when the indicator, such as a hand, is in contact with the operating surface 105A.

[0017] The electrostatic coordinate input device 100 determines five distance states between an indicator such as a hand and the operating surface 105A in order to distinguish between four operating methods. The five distance states are non-detection state, proximity state, selection state, confirmation state, and contact state. The five distance states include a contact state indicating that the operating surface 105A and the indicator such as a hand are in contact, and a plurality of non-contact states indicating that the operating surface 105A and the indicator such as a hand are not in contact. The non-detection state, proximity state, selection state, and confirmation state are non-contact states.

[0018] The non-detection state is a state in which no proximity operation, selection operation, confirmation operation, or contact operation is performed. The proximity state, selection state, confirmation state, and contact state are states in which proximity operation, selection operation, confirmation operation, and contact operation are performed, respectively. The electrostatic coordinate input device 100 uses multiple capacitance thresholds when determining the operation method. As the state progresses from contact state to confirmation state to selection state to proximity state and then to non-detection state, the position of the indicator, such as a hand, moves away from the operation surface 105A.

[0019] Furthermore, the electrostatic coordinate input device 100 is an input device operated by the user through a pointing operation. A pointing operation is an operation performed by holding a finger approximately perpendicular to the operating surface 105A. Multiple fingers may be used for the pointing operation, but one finger is preferred.

[0020] When performing such a pointing operation, if the finger is not approximately perpendicular to the operating surface 105A, the entire palm will approach the operating surface 105A, causing a significant change in the capacitance value detected by the electrostatic coordinate input device 100. Therefore, the electrostatic coordinate input device 100 determines whether the pointing operation is being performed correctly.

[0021] In the following, operations that are not performed correctly using a finger pointing motion, typically involving the entire palm, will be referred to as non-pointing operations. The electrostatic coordinate input device 100 determines whether the user's operation is a finger pointing operation or a non-pointing operation. If a finger pointing operation is detected consecutively a predetermined number of times (for example, three times), the electrostatic coordinate input device 100 determines that a finger pointing operation has been performed. Similarly, if a non-pointing operation is detected consecutively a predetermined number of times (for example, three times), the electrostatic coordinate input device 100 determines that a non-pointing operation has been performed. The reason for determining the operation method based on a predetermined number of consecutive finger pointing or non-pointing operations is to prevent misjudgment of the operation method in the event of sudden noise or other unforeseen circumstances. Further details will be discussed later; here, we will explain four operation methods.

[0022] Furthermore, the following section describes the case where the user operates with hand H as an example of a pointing object. In the following, performing an operation with hand H by pointing or not pointing (proximity operation, selection operation, confirmation operation, or contact operation) will be simply referred to as operating with hand H (proximity operation, selection operation, confirmation operation, or contact operation).

[0023] Proximity operation is an operation in which the hand H is brought close to the operating surface 105A of the electrostatic coordinate input device 100 without touching the operating surface 105A, and is an operation to switch the electrostatic coordinate input device 100 from the standby state shown in Figure 2 to the operating state shown in Figure 1.

[0024] A selection operation is an operation in which, from a proximity operation state, the hand H is brought even closer to the operating surface 105A of the electrostatic coordinate input device 100 without touching the operating surface 105A, and a GUI button displayed on the display device 110 is selected.

[0025] A confirmation operation is an operation in which, after performing a selection operation, the user brings their hand H closer to the operating surface 105A of the electrostatic coordinate input device 100 without touching the operating surface 105A, thereby confirming the operation input for the selected GUI button. A confirmation operation is a contactless operation input, meaning that the electrostatic coordinate input device 100 is operated without touching the operating surface 105A with the hand H. Operation inputs performed by contactless selection and confirmation operations may also be called hover inputs or touchless inputs.

[0026] A contact operation is an operation in which, after making a selection, the user brings their hand H closer to the operating surface 105A of the electrostatic coordinate input device 100 and touches the operating surface 105A to confirm the operation input for the selected GUI button. A contact operation may also be called a touch input.

[0027] <Display device 110> The display device 110 is, for example, a liquid crystal display or an organic EL (electroluminescence) display. The display device 110 is a display for realizing a GUI (Graphical User Interface). The display device 110 displays images of GUI buttons 111, a cursor, and an image of an input content display unit 115 that displays the input content. The GUI buttons 111 are an example of an operation unit, and for example they are arranged in a matrix in a plan view. Also, for example the GUI buttons 111 are circular and resemble push buttons.

[0028] Figures 1 to 3 show, as an example, a total of 45 GUI buttons 111: 26 alphabetical GUI buttons 111, 15 numeric keypad-style GUI buttons 111, and 4 GUI buttons 111: a menu key (three-line key in the upper left), a Caps Lock key, a backspace key (upper right), and an Enter key (lower right). The 45 GUI buttons 111 are arranged in 5 rows in the Y direction and 11 rows in the X direction. Rows extend in the X direction, and Y extends in the column direction. Note that the GUI buttons 111 are not limited to alphabetical characters or numeric keypad numbers, but may also be characters or symbols from other languages.

[0029] This description focuses on a configuration in which a total of 45 GUI buttons 111 are displayed by the display device 110. However, the electrostatic coordinate input device 100 may have an operating section on the top panel 105 with letters, numbers, or symbols printed on it, instead of all or at least some of the 45 GUI buttons 111. For example, a backlight may be provided on the back of the top panel 105, and the operating section with letters, numbers, or symbols printed on it may be made transmissive. When the electrostatic coordinate input device 100 is in standby mode, the backlight may be turned off, and when the electrostatic coordinate input device 100 switches to input mode, the backlight may be turned on so that the letters, numbers, or symbols on the operating section of the top panel 105 are illuminated. In this case, a liquid crystal display or an organic EL display may be provided only in the input content display section 115 to display the input content.

[0030] <Electrostatic sensor 120> The electrostatic sensor 120 is placed on top of the display device 110 and, as shown in Figure 3, has a plurality of sensor electrodes 121X extending in the X direction and a plurality of sensor electrodes 121Y extending in the Y direction. Sensor electrodes 121X and 121Y are examples of electrodes in the detection unit and are connected to the control device 130 via wiring 122X and 122Y, respectively. As an example, such an electrostatic sensor 120 can be made by forming a transparent conductive film such as ITO (Indium Tin Oxide) on the surface of transparent glass and patterning it onto the sensor electrodes 121X and 121Y and the wiring 122X and 122Y. The capacitance detected by the electrostatic sensor 120 is input to the control device 130. The capacitance detected by the electrostatic sensor 120 is an example of the detection result of the electrostatic sensor 120.

[0031] Figure 3 shows, as an example, multiple sensor electrodes 121X and multiple sensor electrodes 121Y. The spacing between sensor electrodes 121X and sensor electrodes 121Y is narrower than the spacing between GUI buttons 111.

[0032] Multiple sensor electrodes 121X are scanned one row at a time, and multiple sensor electrodes 121Y are scanned one column at a time. The AD conversion unit 132 converts the capacitance at multiple intersections of the multiple sensor electrodes 121X and multiple sensor electrodes 121Y into digital values. The counter 133 counts the change in the output of the AD conversion unit 132 and outputs the difference value ΔAD at each intersection. It is also possible to increase the resolution by interpolation, using the spacing between sensor electrodes 121X and sensor electrodes 121Y. In this case, the spacing between sensor electrodes 121X and sensor electrodes 121Y may be wider than the spacing between GUI buttons 111. Although not shown in the diagram, when using interpolation, there may be a one-to-one correspondence between GUI buttons 111 and sensor electrodes of similar size.

[0033] The position of hand H in the XY coordinates detected by the electrostatic coordinate input device 100 using the electrostatic sensor 120 is, for example, the XY coordinate with the largest capacitance within the area where hand H is located. Furthermore, the position of hand H in the Z direction detected by the electrostatic coordinate input device 100 using the electrostatic sensor 120 is inversely proportional to the capacitance detected by the electrostatic sensor 120. Therefore, determining the position of hand H in the Z direction is equivalent to determining the capacitance between hand H and the electrostatic sensor 120. The electrostatic coordinate input device 100 determines the position of hand H in the Z direction using the capacitance between hand H and the electrostatic sensor 120, for example. However, in the following explanation, the position of hand H in the Z direction will be described as such when it is easier to understand.

[0034] <Control device 130> The control unit 130 is implemented by a computer that includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), input / output interfaces, and an internal bus.

[0035] The control device 130 comprises a main control unit 131, an AD (Analog to Digital) conversion unit 132, a counter 133, a calculation unit 134, an operation control unit 135, a display control unit 136, and a memory 137. The main control unit 131, the AD conversion unit 132, the counter 133, the calculation unit 134, the operation control unit 135, and the display control unit 136 represent the functions of the program executed by the control device 130 as functional blocks. The memory 137 functionally represents the memory of the control device 130.

[0036] The main control unit 131 is a processing unit that oversees the processing of the control device 130 and performs processing other than that performed by the AD conversion unit 132, counter 133, calculation unit 134, operation control unit 135, and display control unit 136. For example, the main control unit 131 performs scanning of multiple sensor electrodes 121X and multiple sensor electrodes 121Y.

[0037] The AD conversion unit 132 converts the output of the electrostatic sensor 120 into a digital value. The output of the AD conversion unit 132 is the detected capacitance value at each intersection of the sensor electrodes 121X and 121Y of the electrostatic sensor 120. The counter 133 counts and outputs the difference value of the output of the AD conversion unit 132 relative to a reference value. The difference value is the count value of the change in the output relative to the reference value. Hereinafter, this will be referred to as the difference value ΔAD. The reference value is the capacitance at each intersection of the sensor electrodes 121X and 121Y when there are no fingers around the sensor electrodes 121X and 121Y. The difference value ΔAD is the capacitance between each intersection of the sensor electrodes 121X and 121Y and a finger.

[0038] The difference value ΔAD is obtained for each intersection. The AD conversion unit 132 converts the capacitance at each intersection of the sensor electrodes 121X and 121Y into a digital value, and the counter 133 counts the change in the output of the AD conversion unit 132 relative to a reference value and outputs the difference value ΔAD for each intersection.

[0039] The calculation unit 134 determines the position of the hand H in the XY coordinate system and the position of the hand H in the Z direction from the operating surface 105A based on the difference value ΔAD output from the counter 133. The calculation unit 134 determines the distance state between the hand H and the operating surface 105A using the proximity capacitance threshold, selection capacitance threshold, definitive capacitance threshold, and contact capacitance threshold, which will be described later. As described above, the distance state between the hand H and the operating surface 105A can be undetected, proximity, selection, definitive, or contact.

[0040] The motion control unit 135 controls the operation of the electrostatic coordinate input device 100 based on the position of the hand H determined by the calculation unit 134. The display control unit 136 controls the display of the display device 110 based on the position of the hand H determined by the calculation unit 134. The memory 137 stores programs and data used by the main control unit 131, calculation unit 134, motion control unit 135, and display control unit 136 when they execute processing. The memory 137 also stores data representing the number of rows and columns of the sensor electrodes 121X and 121Y.

[0041] <Pointing and Non-Pointing Operations> Figures 4A to 4C illustrate examples of pointing and non-pointing operations. Figures 4A to 4C show the positions corresponding to the first threshold TH1 and second threshold TH2 for determining the presence or absence of a hand H using the electrostatic sensor 120. Since the second threshold TH2 is larger than the first threshold TH1, the position corresponding to the second threshold TH2 is closer to the operating surface 105A than the position corresponding to the first threshold TH1. Determining the size of a hand H using these first and second thresholds TH1 is equivalent to measuring the cross-sectional area of ​​the hand H.

[0042] Figure 4A shows a state in which the fingertip FT of hand H is brought perpendicular to the operating surface 105A of the top panel 105, and a pointing operation is being performed. The electrostatic coordinate input device 100 determines whether a pointing operation is being performed by the fingertip FT or whether a non-pointing operation is being performed with the palm without extending the finger, based on the projected area of ​​hand H from the tip of the fingertip FT to a predetermined distance away. If a pointing operation is being performed as shown in Figure 4A, the electrostatic coordinate input device 100 can determine that a pointing operation is being performed by the fingertip FT.

[0043] Figure 4B shows a state in which a non-pointing operation is performed by bringing the hand H close to the operating surface 105A of the top panel 105 with all fingers clenched without extending the fingers. In this case, the projected area of ​​the hand H at the position corresponding to the first threshold TH1 becomes large, so the electrostatic coordinate input device 100 can determine that a non-pointing operation is being performed.

[0044] Figure 4C shows a state in which a non-pointing operation is performed by bringing the fingertip FT of hand H diagonally close to the operating surface 105A of the top panel 105. Although one finger is pointing to the operating surface 105A, the fingertip FT is at an angle to the operating surface 105A, and the palm is also close to the operating surface 105A, so the projected area of ​​hand H at the position corresponding to the first threshold TH1 is large. For this reason, the electrostatic coordinate input device 100 can determine that a non-pointing operation is being performed.

[0045] <Threshold for distance state determination> Figure 5 shows an example of thresholds for determining distance states. Figure 5 shows thresholds for determining five distance states: undetected, proximity, selection, confirmation, and contact.

[0046] Figure 5 shows the on-threshold and off-threshold for each of the five distance states. The on-threshold is used to determine whether a distance state is met. When the maximum capacitance detected by the electrostatic sensor 120 exceeds the on-threshold, the distance state becomes the distance state corresponding to that on-threshold. The off-threshold is used to determine whether a distance state is no longer met. When the maximum capacitance detected by the electrostatic sensor 120 falls below the off-threshold, the distance state no longer corresponds to the distance state corresponding to that off-threshold. For each distance state, the on-threshold is set to a capacitance greater than the off-threshold, and hysteresis is provided to stabilize the distance state.

[0047] For the non-detection state, no on-threshold or off-threshold is set. The on-threshold for the proximity state is 26, and the off-threshold is 19. The on-threshold for the selected state is 103, and the off-threshold is 88. The on-threshold for the confirmed state is 273, and the off-threshold is 226. The on-threshold for the contact state is 1153, and the off-threshold is 961. These values ​​are obtained by digitally converting the capacitance detected by the electrostatic sensor 120 into count values.

[0048] The on-threshold and off-threshold ranges for the proximity, selection, confirmation, and contact states are set so that they do not overlap with each other.

[0049] The electrostatic coordinate input device 100 uses the on threshold and off threshold shown in Figure 5 to determine the distance state in the current process according to the distance state in the previous process (previous control cycle). The determination process is summarized in Figure 6.

[0050] Figure 6 is a diagram that summarizes the distance state determined by the electrostatic coordinate input device 100, showing the relationship between the maximum capacitance and the previous distance state.

[0051] As shown in Figure 6, if the maximum capacitance is 1154 or greater, the current distance state is determined to be a contact state, regardless of the previous distance state.

[0052] Furthermore, if the maximum capacitance is between 962 and 1153, and the previous distance state was a contact state, the current distance state is determined to be a contact state.

[0053] Furthermore, if the maximum capacitance is between 962 and 1153, and the previous distance state was below the confirmed state, the current distance state is determined to be confirmed. Below the confirmed state means that the distance state is either undetected, close, selected, or confirmed.

[0054] Furthermore, if the maximum capacitance is between 274 and 961, the current distance state is determined to be a fixed state, regardless of the previous distance state.

[0055] Furthermore, if the maximum capacitance is between 227 and 273, and the previous distance state was a confirmed state or better, the current distance state is determined to be a confirmed state. A confirmed state or better means that the distance state is either a contact state or a confirmed state.

[0056] Furthermore, if the maximum capacitance is between 227 and 273, and the previous distance state was below the selected state, the current distance state is determined to be the selected state. Below the selected state means that the distance state is either undetected, close, or selected.

[0057] Furthermore, if the maximum capacitance is between 104 and 226, the current distance state is determined to be the selected state, regardless of the previous distance state.

[0058] Furthermore, if the maximum capacitance is between 89 and 103, and the previous distance state was at or above the selected state, the current distance state is determined to be the selected state. "At or above the selected state" means that the distance state is either the contact state, the confirmed state, or the selected state.

[0059] Furthermore, if the maximum capacitance is between 89 and 103, and the previous distance state was close or less, the current distance state is determined to be close. Close or less means that the distance state is either undetected or close.

[0060] Furthermore, if the maximum capacitance is between 27 and 88, the current distance state is determined to be a close-proximity state, regardless of the previous distance state.

[0061] Furthermore, if the maximum capacitance is between 20 and 26, and the previous distance state was close or better, the current distance state is determined to be close. Close or better means that the distance state is either contact, confirmed, selected, or close.

[0062] Furthermore, if the maximum capacitance is between 20 and 26, and the previous distance state was undetected, the current distance state is determined to be undetected.

[0063] Furthermore, if the maximum capacitance is between 0 and 19, the current distance state is determined to be undetected, regardless of the previous distance state.

[0064] <Overall processing> Figure 7 is a flowchart showing the process executed by the control device 130 of the electrostatic coordinate input device 100. The flow shown in Figure 7 is called and executed by application software (not shown). If the application software is in a state of waiting for input, the flow shown in Figure 7 is repeatedly executed from start to end at a predetermined control cycle.

[0065] When the control device 130 starts processing, the calculation unit 134 acquires the capacitance of each electrode (each of the sensor electrodes 121X and 121Y) (step S1).

[0066] The calculation unit 134 calculates the position (XY coordinates) of hand H (step S2). The position (XY coordinates) of hand H is the position of the detection point of the largest capacitance among the capacitances obtained in step S1.

[0067] The calculation unit 134 determines the distance state between the fingertip FT and the operating surface 105A based on the maximum capacitance obtained in step S2 (step S3). The process in step S3 is a subroutine process for determining the distance state, which will be described later using Figure 8. As a result of the process in step S3, the distance state between the hand H and the operating surface 105A is specified to one of the distance states.

[0068] The calculation unit 134 performs a non-pointing operation determination to determine whether a non-pointing operation is being performed (step S4). The process in step S4 is a subroutine process and will be described later using Figure 8. The process in step S4 determines whether a non-pointing operation is being performed with hand H.

[0069] The calculation unit 134 outputs data representing the position of hand H (XY coordinates), maximum capacitance, distance status, and whether or not a non-pointing operation was performed (step S5).

[0070] When the calculation unit 134 completes the processing in step S5, it terminates the series of processes (end).

[0071] <Distance State Determination Process> Figure 8 is a flowchart showing an example of the distance state determination process. The process shown in Figure 8 is the subroutine process of step S3 in Figure 7.

[0072] When the calculation unit 134 starts the distance state determination process, it determines whether the maximum capacitance obtained in step S2 exceeds 1153 (step S31). This is to determine whether a contact state exists.

[0073] If the calculation unit 134 determines that the maximum capacitance exceeds 1153 (S31: Yes), it determines that the distance state is a contact state (step S31A). After completing the processing in step S31A, the calculation unit 134 finishes the distance state determination processing (subroutine processing) and proceeds to step S4.

[0074] If the calculation unit 134 determines in step S31 that the maximum capacitance does not exceed 1153 (S31: No), it then determines in step S2 whether the maximum capacitance obtained exceeds 961 (step S32).

[0075] If the calculation unit 134 determines that the maximum capacitance exceeds 961 (S32: Yes), it determines whether the previous distance state was a contact state (step S32A).

[0076] If the calculation unit 134 determines that the previous distance state was a contact state (S32A: Yes), it proceeds to step S31A and determines that the distance state is a contact state (step S31A). After completing the processing in step S31A, the calculation unit 134 terminates the series of processes (end).

[0077] If the calculation unit 134 determines in step S32 that the maximum capacitance obtained in step S2 does not exceed 961 (S32: No), or if it determines in step S32A that the previous distance state was not a contact state (S32A: No), it determines in step S33 whether the maximum capacitance obtained in step S2 exceeds 273.

[0078] If the calculation unit 134 determines that the maximum capacitance exceeds 273 (S33: Yes), it determines that the distance state is in a determined state (step S33A). After completing the process in step S33A, the calculation unit 134 terminates the series of processes (end).

[0079] If the calculation unit 134 determines in step S33 that the maximum capacitance does not exceed 273 (S33: No), it then determines whether the maximum capacitance obtained in step S2 exceeds 226 (step S34).

[0080] If the calculation unit 134 determines that the maximum capacitance exceeds 226 (S34: Yes), it determines whether the previous distance state was a contact state or a confirmed state (step S34A).

[0081] If the calculation unit 134 determines that the previous distance state was either a contact state or a confirmed state (S34A: Yes), it determines that the distance state is a confirmed state (step S34B). After completing the process in step S34B, the calculation unit 134 terminates the series of processes (end).

[0082] If the calculation unit 134 determines in step S34 that the maximum capacitance does not exceed 226 (S34: No), or if it determines in step S34A that the previous distance state was neither a contact state nor a confirmed state (S34A: No), then it determines whether the maximum capacitance obtained in step S2 exceeds 103 (step S35). If the previous distance state was not a confirmed state, then the previous distance state was less than or equal to the selected state.

[0083] If the calculation unit 134 determines that the maximum capacitance exceeds 103 (S35: Yes), it determines that the distance state is the selected state (step S35A). After completing the process in step S35A, the calculation unit 134 terminates the series of processes (end).

[0084] If the calculation unit 134 determines in step S35 that the maximum capacitance does not exceed 103 (S35: No), it then determines whether the maximum capacitance obtained in step S2 exceeds 88 (step S36).

[0085] If the calculation unit 134 determines that the maximum capacitance exceeds 88 (S36: Yes), it determines whether the previous distance state was a contact state, a confirmed state, or a selected state (step S36A).

[0086] If the calculation unit 134 determines that the previous distance state was either contact state, confirmed state, or selected state (S36A: Yes), it determines that the distance state is selected (step S36B). After completing the process in step S36B, the calculation unit 134 terminates the series of processes (end).

[0087] If the calculation unit 134 determines in step S36 that the maximum capacitance does not exceed 88 (S36: No), or if it determines in step S36A that the previous distance state was not a contact state, a confirmed state, or a selected state (S36A: No), then it determines whether the maximum capacitance obtained in step S2 exceeds 26 (step S37). The fact that the previous distance state was not a contact state, a confirmed state, or a selected state means that the previous distance state was close or less.

[0088] If the calculation unit 134 determines that the maximum capacitance exceeds 26 (S37: Yes), it determines that the distance state is the proximity state (step S37A). After completing the process in step S37A, the calculation unit 134 terminates the series of processes (end).

[0089] If the calculation unit 134 determines in step S37 that the maximum capacitance does not exceed 26 (S37: No), it then determines whether the maximum capacitance obtained in step S2 exceeds 19 (step S38).

[0090] If the calculation unit 134 determines that the maximum capacitance exceeds 19 (S38: Yes), it determines whether the previous distance state was contact state, confirmed state, selected state, or proximity state (step S38A).

[0091] If the calculation unit 134 determines that the previous distance state was the proximity state (S38A: Yes), it determines that the current distance state is the proximity state (step S38B). After completing the process in step S38B, the calculation unit 134 terminates the series of processes (end).

[0092] If the calculation unit 134 determines in step S38 that the maximum capacitance does not exceed 19 (S38: No), or if it determines in step S38A that the previous distance state was not the contact state, confirmed state, selected state, or proximity state (S38A: No), then it determines that the distance state is not detected (step S39). After completing the processing in step S39, the calculation unit 134 terminates the series of processes (end).

[0093] <Non-pointing operation detection process> Figure 9 shows an example of a table data of thresholds used in non-pointing operation detection processing. The thresholds used in non-pointing operation detection processing are the non-pointing detection threshold, the pointing detection threshold, and the detection count threshold. The non-pointing detection threshold, the pointing detection threshold, and the detection count threshold are provided for each of the non-detection state, proximity state, selection state, confirmation state, and contact state.

[0094] The non-pointing detection threshold is a threshold used to determine a non-pointing operation based on the maximum capacitance detected by the electrostatic sensor 120. The pointing detection threshold is a threshold used to determine a pointing operation based on the maximum capacitance detected by the electrostatic sensor 120. The judgment count threshold is a threshold used to distinguish between non-pointing operations and pointing operations.

[0095] The non-pointing detection threshold is a threshold used to determine whether a non-pointing operation is being performed, based on the capacitance detected by the electrostatic sensor 120 in each of the non-detection, proximity, selection, confirmation, and contact states. If the number of detection points where the capacitance exceeds the non-pointing detection threshold exceeds the determination threshold, it is determined that a non-pointing operation is being performed.

[0096] The pointing detection threshold is a threshold used to determine whether a pointing operation is being performed, based on the capacitance detected by the electrostatic sensor 120 in each of the non-detection, proximity, selection, confirmation, and contact states. If the number of detection points where the capacitance exceeds the pointing detection threshold is less than or equal to the detection count threshold, it is determined that a pointing operation is being performed.

[0097] The judgment count threshold, as described above, is a threshold that is compared with the number of detection points whose capacitance exceeds the pointing detection threshold when determining whether a non-pointing operation or a pointing operation is being performed. The value of the judgment count threshold represents the number of detection points of the electrostatic sensor 120.

[0098] As shown in Figure 9, the non-pointing detection threshold is the same for the non-detection and proximity states, but increases as the operating state becomes closer to the hand H and the operating surface 105A, from the non-detection and proximity states to the selection, confirmation, and contact states. More specifically, it is set to 60 for the non-detection and proximity states, to 90 for the selection state, to 220 for the confirmation state, and to 2500 for the contact state. Thus, the non-pointing detection threshold is set to a larger value the shorter the distance represented by the multiple distance states.

[0099] Furthermore, the pointing detection threshold is set to 50 for non-detection, proximity, selection, and confirmation states, and to 2000 for contact states.

[0100] As shown in Figure 9, the non-pointing detection threshold in the contact state is greater than the non-pointing detection thresholds in multiple non-contact states (non-detection state, proximity state, selection state, and confirmation state), and the pointing detection threshold in the contact state is greater than the pointing detection thresholds in multiple non-contact states. Furthermore, the detection count threshold in the contact state is smaller than the detection count thresholds in multiple non-contact states (non-detection state, proximity state, selection state, and confirmation state).

[0101] Figure 10 is a flowchart showing the process for determining whether a pointing operation was performed. The process shown in Figure 8 is the subroutine process of step S4 in Figure 7.

[0102] When the calculation unit 134 starts the non-pointing operation determination process, it sets the non-pointing operation threshold, the pointing operation threshold, and the determination count threshold based on the threshold table data shown in Figure 9, according to the distance state (step S41).

[0103] The calculation unit 134 determines whether the previous operation was a pointing operation (step S42).

[0104] If the calculation unit 134 determines that the variable "operation state" is "pointing operation" (S42: Yes), it determines whether the number of detection points where the capacitance exceeds the non-pointing operation threshold exceeds the determination number threshold (step S43A). Step S43A is the process of determining whether a non-pointing operation is being performed.

[0105] If the calculation unit 134 determines that the number of detection points where the capacitance exceeds the non-pointing operation threshold does not exceed the determination count threshold (S43A: No), it resets the non-pointing operation count to 0 (step S44A). The non-pointing operation count represents the number of times that a non-pointing operation was determined to have been provisionally performed by determining Yes in step S43A. After completing the processing in step S44A, the calculation unit 134 finishes the series of processes (end).

[0106] If the calculation unit 134 determines in step S43A that the number of detection points whose capacitance exceeds the non-pointing operation threshold exceeds the determination count threshold (S43A: Yes), it increments the non-pointing operation count (step S45A).

[0107] The calculation unit 134 determines whether the number of non-pointing operations is three or more (step S46A).

[0108] If the calculation unit 134 determines that the number of non-pointing operations is not three or more (S46A: No), it terminates the series of operations (end).

[0109] If the calculation unit 134 determines in step S46A that the number of non-pointing operations is 3 or more (S46A: Yes), it changes the variable "operation status" to "non-pointing operation" (step S47A). The number of non-pointing operations will not reach 3 unless it is determined to be Yes three times in a row in step S43A.

[0110] Therefore, if, for three consecutive times in step S43A, the number of detection points in which the capacitance exceeds the non-pointing operation threshold exceeds the threshold for the number of detection points (S43A: Yes), then the operation of hand H is determined to be a non-pointing operation. In order to prevent misjudgment of the operation method in the event of sudden noise, etc., the operation of hand H is determined to be a non-pointing operation if, for three consecutive times, the number of detection points in which the capacitance exceeds the non-pointing operation threshold exceeds the threshold for the number of detection points (S43A: Yes).

[0111] The calculation unit 134 resets the number of pointing operations to 0 (step S48A). After completing the process in step S48A, the calculation unit 134 finishes the series of processes (end).

[0112] Furthermore, if the calculation unit 134 determines in step S42 that the previous operation was not a pointing operation (S42: No), it determines whether the number of detection points where the capacitance exceeds the pointing operation threshold is less than or equal to the determination number threshold (step S43B). Step S43B is the process of determining whether a non-pointing operation has been performed.

[0113] If the calculation unit 134 determines that the number of detection points where the capacitance exceeds the pointing operation threshold is not less than or equal to the determination count threshold (S43B: No), it resets the number of pointing operations to 0 (step S44B). The number of pointing operations represents the number of times that a pointing operation was determined to have been performed provisionally, as determined by Yes in step S43B. After completing the processing in step S44B, the calculation unit 134 finishes the series of processes (end).

[0114] In step S43B, the calculation unit 134 determines that the number of detection points whose capacitance exceeds the non-pointing threshold is less than or equal to the determination threshold (S43B: Yes), and increments the number of pointing operations (step S45B).

[0115] The calculation unit 134 determines whether the number of pointing operations is three or more (step S46B).

[0116] If the calculation unit 134 determines that the number of pointing operations is not three or more (S46B: No), it terminates the series of operations (end).

[0117] If the calculation unit 134 determines in step S46B that the number of pointing operations is 3 or more (S46B: Yes), it changes the variable "operation state" to "pointing operation" (step S47B). The number of pointing operations will not reach 3 unless it is determined to be Yes three times in a row in step S43B.

[0118] Therefore, if, for three consecutive times in step S43B, the number of detection points where the capacitance exceeds the pointing operation threshold is determined to be less than or equal to the determination threshold (S43B: Yes), then the operation of hand H is determined to be a pointing operation. In order to prevent misjudgment of the operation method in the event of sudden noise, etc., the operation of hand H is determined to be a pointing operation only if, for three consecutive times, the number of detection points where the capacitance exceeds the pointing operation threshold is determined to be less than or equal to the determination threshold (S43B: Yes).

[0119] The calculation unit 134 resets the number of non-pointing operations to 0 (step S48B). After completing the process in step S48B, the calculation unit 134 completes the series of operations (end).

[0120] <Distribution of capacitance detected by electrostatic sensor 120> Figures 11A to 11D show an example of the capacitance distribution detected by the electrostatic sensor 120. As an example, in Figures 11A to 11D, the sensor electrodes 121X and 121Y intersect at 18 points in the X direction and 18 points in the Y direction in a plan view, and the electrostatic sensor 120 can detect capacitance at 324 detection points in an 18x18 grid. Therefore, Figures 11A to 11D show 324 frames in an 18x18 grid.

[0121] Furthermore, detection points where capacitance exceeding the second threshold TH2, as shown in Figures 4A to 4C, is detected are indicated with an "x," and detection points where capacitance exceeding the first threshold TH1 but less than or equal to the second threshold TH2 are indicated with a " / ." Detection points where capacitance is less than or equal to the first threshold TH1 are not shown with an "x" or " / ," but are instead shown in white.

[0122] In Figure 11A, there are eight "x" marks in the upper left corner, and no " / " marks. The "x" marks indicate, for example, detection points where hand H is in contact. Since the number of these marks is less than the threshold of 12, the electrostatic coordinate input device 100 determines that a pointing operation in contact state is being performed. The coordinates of the pointing operation in contact state are the location of the detection point with the maximum capacitance among the eight detection points indicated by the "x" marks.

[0123] In Figure 11B, there are eight "x" marks in the upper left and 64 " / " ​​marks below the center. The "x" marks represent, for example, detection points where hand H is in contact. Since the number of these marks exceeds the threshold of 12, the electrostatic coordinate input device 100 determines that a non-pointing operation in a contact state is occurring. The coordinates of the non-pointing operation in a contact state are the location of the detection point with the maximum capacitance among the 72 detection points indicated by the "x" marks.

[0124] In Figure 11C, there are eight "x" marks in the upper left corner, and 37 " / " marks around the "x" marks. In Figure 11C, the "x" marks represent, for example, detection points where hand H is in a confirmed state, and since the number of these marks is less than or equal to the threshold value of 90, the electrostatic coordinate input device 100 determines that a confirmed pointing operation has been performed. The coordinates of the confirmed pointing operation are the position of the detection point with the maximum capacitance among the detection points indicated by the eight "x" marks.

[0125] In Figure 11D, there are eight "x" marks in the upper left corner, and 100 " / " marks around the "x" marks. In Figure 11D, the "x" marks represent, for example, detection points where hand H is in a confirmed state. Since the number of these marks exceeds the threshold of 90, the electrostatic coordinate input device 100 determines that a non-pointing operation in a confirmed state has been performed. The coordinates of the non-pointing operation in a confirmed state are the location of the detection point with the maximum capacitance among the detection points indicated by the eight "x" marks.

[0126] <Example of operation of electrostatic coordinate input device 100> Figures 12A to 12E show examples of operation of the electrostatic coordinate input device 100. Figures 12A to 12E explain the case when a pointing operation is performed. Figures 12A to 12E show a simplified representation of the numeric keypad portion and the input content display unit 115 of the electrostatic coordinate input device 100 shown in Figure 1.

[0127] In Figure 12A, the electrostatic coordinate input device 100 is in standby mode, with the backlight off and the keypad and input content display unit 115 dark. In Figure 12A, the distance status is not detected.

[0128] In Figure 12B, hand H is close to the operating surface 105A, and the distance state is the close-range state. In the close-range state, the electrostatic coordinate input device 100 switches from standby state to active state, and the backlights of all keys and the input content display unit 115 are illuminated. With the backlights on, the numeric keypad and the input content display unit 115 are brightly lit.

[0129] In Figure 12C, hand H is even closer to the operating surface 105A, and the distance state is selected. As an example, fingertip FT is positioned above key 7, and the backlights of key 7 and the surrounding keys 4, 5, 8, C, and 0 are illuminated, while the backlights of the other keys are turned off.

[0130] In Figure 12D, hand H is even closer to the operating surface 105A, and the distance state is confirmed. For example, fingertip FT is positioned above key 7, and only the backlight of key 7, which has been confirmed to be operated, is lit, while the backlights of the other keys are off. Therefore, the user can visually recognize that the operation on key 7 has been confirmed. In Figure 12D, the position of hand H relative to the operating surface 105A is held in the position described in Figure 12D, and the user is waiting for the operation to be confirmed, and the distance state is confirmed.

[0131] In Figure 12E, the position of hand H relative to the operating surface 105A is maintained at the position described in Figure 12D, and the operation is confirmed. Fingertip FT is positioned above the 7 key, and when the operation is confirmed, 7 is displayed on the input content display unit 115.

[0132] Figures 13A to 13F show examples of operation of the electrostatic coordinate input device 100. Figures 13A to 13F describe the case in which, after the input of the number 7 is confirmed as explained in Figure 12E, the hand H is moved sufficiently away from the operating surface 105A, and then the non-pointing operation shown in Figure 4C is performed. The non-pointing operation shown in Figure 4C is one in which the fingertip FT is at an angle to the operating surface 105A, and the palm is also close to the operating surface 105A. Figures 13A to 13F show a simplified representation of the numeric keypad portion and the input content display unit 115 of the electrostatic coordinate input device 100 shown in Figure 1.

[0133] In Figure 13A, the electrostatic coordinate input device 100 is dark because the distance status is not detected, and the backlight for the numeric keypad is turned off. However, the backlight for the input content display unit 115 is turned on to display the input content.

[0134] In Figure 13B, the non-pointing hand H is close to the operating surface 105A, and the distance state is a close-range state. When the distance state is reached, the electrostatic coordinate input device 100 illuminates the backlights for all keys and the input content display unit 115. However, because the electrostatic coordinate input device 100 has detected that a non-pointing operation is being performed, the warning message "Please bring your fingertips closer" is displayed on the input content display unit 115. This is to encourage the user to perform a pointing operation.

[0135] In Figure 13C, the non-pointing hand H is even closer to the operating surface 105A, and the distance state is selected. For example, the maximum capacitance is located above the 5 key, but because it is a non-pointing operation, the backlights of the 7 key and the surrounding keys 4, 5, 8, C, and 0 are illuminated, while the backlights of the other keys are turned off.

[0136] In Figure 13D, hand H is even closer to the operating surface 105A, and the distance state is fixed. For example, fingertip FT is positioned above key 5, and only the backlight of key 5 is lit, while the backlights of the other keys are off. Even in this state, because fingertip FT is at an angle, the input content display unit 115 displays the warning message "Please straighten your fingertip."

[0137] Figure 13E shows the state shown in Figure 13D continuing, and the time required to confirm the operation has elapsed, but since it is a non-pointing operation, the operation is not confirmed. Even in this state, because the fingertip FT is at an angle, the input content display unit 115 displays the warning message "Please straighten your fingertip."

[0138] Figure 13F shows the state in which the fingertip FT is raised relative to the operating surface 105A, as described in Figure 13E. Raising the fingertip FT confirms the operation, and in addition to 7, 5 is displayed on the input content display unit 115.

[0139] <Effects> The electrostatic coordinate input device 100 comprises an operating surface 105A, a plurality of sensor electrodes 121X and 121Y arranged on the back side of the operating surface 105A, a measurement circuit (AD conversion unit 132, etc.) for measuring the capacitance of each of the plurality of sensor electrodes 121X and 121Y, and a calculation unit 134 for calculating the position of the indicator based on the plurality of capacitances measured by the measurement circuit (AD conversion unit 132, etc.). The calculation unit 134 calculates the maximum capacitance between the indicator and the sensor electrodes 121X and 121Y based on the plurality of capacitances, sets a non-pointing determination threshold used to determine a non-pointing operation of the indicator based on the maximum capacitance, and determines that the operation of the indicator is a non-pointing operation if the number of capacitances that exceed the non-pointing determination threshold among the plurality of capacitances exceeds the determination number threshold.

[0140] By setting a non-pointing detection threshold based on the maximum capacitance, the cross-sectional area at a certain distance from the operating surface 105A can be measured, using the position closest to the operating surface 105A within the hand H as a reference. In other words, if the cross-sectional area at a position several centimeters away from the fingertip FT is greater than or equal to a predetermined value, it is considered a non-pointing operation where the operating surface 105A is not being pointed at. By accurately determining whether the operating surface 105A is not being pointed at, even without contact, erroneous operations can be prevented.

[0141] Therefore, it is possible to provide an electrostatic coordinate input device 100 that can accurately determine whether or not an operation such as contact or proximity has occurred depending on the distance to the indicator, and can suppress erroneous operations.

[0142] Furthermore, the calculation unit 134 sets a pointing detection threshold based on the maximum capacitance, which is used to determine whether the operation of the indicator is a pointing operation. If the number of capacitances that exceed the pointing detection threshold among multiple capacitances is less than or equal to the detection threshold, it determines that the operation of the indicator is a pointing operation. Therefore, pointing operations can also be determined with high accuracy.

[0143] Furthermore, the calculation unit 134 determines which of the multiple distance states the distance between the indicator and the operating surface 105A corresponds to, based on the maximum capacitance. A non-pointing detection threshold, a pointing detection threshold, and a determination count threshold are defined for each of the multiple distance states, and the non-pointing detection threshold is set to a larger value the shorter the distance represented by the multiple distance states. As a result, an appropriate non-pointing detection threshold can be easily set, and the presence or absence of operations such as contact or proximity can be determined with high accuracy according to the distance to the indicator, thereby providing an electrostatic coordinate input device 100 that can suppress erroneous operations.

[0144] Furthermore, the multiple distance states include a contact state indicating that the operating surface 105A and the indicator are in contact, and multiple non-contact states indicating that the operating surface 105A and the indicator are not in contact. The non-pointing detection threshold in the contact state is greater than the non-pointing detection threshold in the multiple non-contact states, the pointing detection threshold in the contact state is greater than the pointing detection threshold in the multiple non-contact states, and the detection count threshold in the contact state is smaller than the detection count threshold in the multiple non-contact states. In the case of a contact state, pointing operations and non-pointing operations are distinguished by the area in contact. In other words, since the distinction is made by the area in contact with the operating surface 105A, the detection accuracy can be improved by making the non-pointing operation threshold and the pointing operation threshold greater than the non-pointing operation threshold and the pointing operation threshold in the non-contact state. Also, the detection accuracy can be improved by making the detection count threshold in the contact state smaller than the detection count threshold in the multiple non-contact states.

[0145] Furthermore, the pointing detection thresholds for multiple non-contact states are equal to each other, and the detection count thresholds for multiple non-contact states are also equal to each other. Therefore, this is particularly useful when applying an operation method that requires removing the hand H from the operating surface 105A once when a non-pointing operation is detected.

[0146] Furthermore, the multiple non-contact states, ranging from the shortest to the longest distances represented by the multiple distance states, are: the confirmation state where the input content is finalized, the selection state where an input candidate is selected, the proximity state where the user is close to an input candidate, and the non-detection state where the object is not detected. The non-pointing detection threshold for the non-detection state and the non-pointing detection threshold for the proximity state are the same value; the pointing detection threshold for the non-detection state and the pointing detection threshold for the proximity state are the same value; and the detection count threshold for the non-detection state and the detection count threshold for the proximity state are the same value. Therefore, it becomes possible to simultaneously detect hand H when the proximity state is reached and detect non-pointing operations.

[0147] Furthermore, the calculation unit 134 determines that the operation of the indicator is a pointing operation, and if the number of capacitances exceeding the non-pointing determination threshold exceeds the determination count threshold for a predetermined number of consecutive times, the operation of the indicator is determined to be a non-pointing operation. The calculation unit 134 continues to determine that the operation of the indicator is a pointing operation until the number of capacitances exceeding the non-pointing determination threshold exceeds the determination count threshold for a predetermined number of consecutive times. The calculation unit 134 also determines that the operation of the indicator is a pointing operation, and if the number of capacitances exceeding the pointing determination threshold is less than or equal to the determination count threshold for a predetermined number of consecutive times, the operation of the indicator is determined to be a pointing operation. The calculation unit 134 continues to determine that the operation of the indicator is a non-pointing operation until the number of capacitances exceeding the pointing determination threshold is less than or equal to the determination count threshold for a predetermined number of consecutive times. This effectively suppresses false detections due to noise.

[0148] Furthermore, the system includes a display unit (input content display unit 115), and when the calculation unit 134 determines that the operation of the indicator is a non-pointing operation, it displays a message on the display unit (input content display unit 115) requesting the user to perform a pointing operation with the indicator. This allows the user to be guided to perform the operation correctly by pointing with their fingertip FT, thereby suppressing errors.

[0149] The operation determination method for an electrostatic coordinate input device comprises an operating surface 105A, a plurality of sensor electrodes 121X and 121Y arranged on the back side of the operating surface 105A, a measurement circuit (AD conversion unit 132, etc.) for measuring the capacitance of each of the plurality of sensor electrodes 121X and 121Y, and a calculation unit 134 for calculating the position of an indicator based on the plurality of capacitances measured by the measurement circuit (AD conversion unit 132, etc.). The method calculates the maximum capacitance between the indicator and the sensor electrodes 121X and 121Y based on the plurality of capacitances, sets a non-pointing determination threshold used to determine a non-pointing operation that is not a pointing operation of the indicator based on the maximum capacitance, and determines that the operation of the indicator is a non-pointing operation if the number of capacitances that exceed the non-pointing determination threshold among the plurality of capacitances exceeds a determination number threshold.

[0150] By setting a non-pointing detection threshold based on the maximum capacitance, the cross-sectional area at a certain distance from the operating surface 105A can be measured, using the position closest to the operating surface 105A on the hand H as a reference. In other words, if the cross-sectional area at a position several centimeters away from the fingertip FT is greater than or equal to a predetermined value, it is considered a non-pointing operation where the operating surface 105A is not being pointed at. By accurately determining whether the operating surface 105A is not being pointed at, even without contact, erroneous operations can be prevented.

[0151] Therefore, it is possible to provide an operation determination method for an electrostatic coordinate input device that can accurately determine whether or not an operation such as contact or proximity has occurred depending on the distance to the indicator, thereby suppressing erroneous operations.

[0152] <Variation> Figures 14A to 14C show modified examples of the threshold table data used in the non-pointing operation detection process.

[0153] In the table data shown in Figure 14A, the threshold values ​​for the number of detections in multiple non-contact states are equal to each other, and the threshold value for pointing in multiple non-contact states increases as the distance represented by the multiple distance states decreases.

[0154] Specifically, compared to the table data shown in Figure 9, the pointing detection thresholds for the selected and confirmed states have been increased, and are set to 70 and 190, respectively. By increasing the values ​​of the pointing detection thresholds for the selected and confirmed states, it is possible to return to the non-detection state without removing hand H from the operating surface 105A.

[0155] Furthermore, in the table data shown in Figure 14B, the pointing detection thresholds for multiple non-contact states are equal to each other, and the detection threshold for multiple non-contact states is smaller the shorter the distance represented by the multiple distance states.

[0156] Specifically, compared to the table data shown in Figure 9, the threshold values ​​for the number of items to be judged for the selected state and the confirmed state have been reduced, and are set to 56 and 30, respectively. In other words, the threshold values ​​for the number of items to be judged are set to increase as the state progresses from the contact state to the confirmed state, the selected state, the proximity state, and the non-detection state. As a result, the further the hand H moves from the operating surface 105A, the larger the cross-sectional area becomes, allowing for the distinction between pointing and non-pointing operations.

[0157] Furthermore, in the table data shown in Figure 14C, the shorter the distance represented by multiple distance states, the larger the pointing judgment threshold and the smaller the judgment count threshold. Specifically, the data structure is a combination of the table data shown in Figures 14A and 14B.

[0158] Specifically, compared to the table data shown in Figure 9, the pointing detection thresholds for the selected and confirmed states have been increased to 70 and 190, respectively. In addition, the threshold values ​​for the number of items to be judged for the selected and confirmed states have been decreased to 56 and 30, respectively.

[0159] Therefore, by increasing the value of the pointing detection threshold for the selected and confirmed states, it is possible to return to the non-detection state without removing hand H from the operating surface 105A. Furthermore, the further hand H is from the operating surface 105A, the larger the cross-sectional area, allowing for better distinction between pointing and non-pointing operations.

[0160] Figure 15 is a flowchart showing a modified version of the non-pointing operation detection process. The flowchart in Figure 15 is obtained by replacing the process in step S41 with step S41M in the flowchart showing the non-pointing operation detection process shown in Figure 10. The processes from step S42 onward are the same as the flowchart showing the non-pointing operation detection process shown in Figure 10. Therefore, the process in step S41M will be explained here.

[0161] The calculation unit 134 sets the non-pointing operation threshold to a value obtained by multiplying the maximum value of the capacitance detected by the electrostatic sensor 120 during that control cycle by a coefficient of 0.8, sets the pointing operation threshold to a value obtained by multiplying the maximum value of the capacitance detected by the electrostatic sensor 120 during that control cycle by a coefficient of 0.5, and sets the judgment count threshold to a value obtained by dividing the maximum value of the capacitance detected by the electrostatic sensor 120 during that control cycle by 10000 (step S41M).

[0162] In other words, the non-pointing detection threshold is a value proportional to the maximum capacitance. The coefficient multiplied by the maximum capacitance is not limited to 0.8, but can be set to an appropriate value. Similarly, the pointing detection threshold is a value proportional to the maximum capacitance. The coefficient multiplied by the maximum capacitance is not limited to 0.5, but can be set to an appropriate value as long as it is smaller than the coefficient multiplied by the non-pointing operation threshold. In other words, the pointing detection threshold is a value greater than the non-pointing detection threshold. Furthermore, the detection count threshold is a value inversely proportional to the maximum capacitance. For this reason, non-pointing operations can be detected without using threshold table data as shown in Figures 9 and 14A to 14C.

[0163] Although exemplary embodiments of the electrostatic coordinate input device and the operation determination method in the electrostatic coordinate input device have been described above, the present disclosure is not limited to the specifically disclosed embodiments, and various modifications and changes are possible without departing from the scope of the claims.

[0164] This international application claims priority based on Japanese Patent Application No. 2022-178084, filed on November 7, 2022, the entire contents of which are incorporated herein by reference. [Explanation of Symbols]

[0165] 100 Electrostatic Coordinate Input Device 101 cabinets 105 Top Panel 105A Operation surface 110 Display device 111 GUI buttons 115 Input content display section 120 electrostatic sensors 121X sensor electrode 121Y sensor electrode 122X Wiring 122Y Wiring 130 Control device 131 Main Control Unit 132 AD Conversion Unit 133 counter 134 Calculation Section 135 Operation Control Unit 136 Display Control Unit 137 memory

Claims

1. The operating surface, Multiple sensor electrodes arranged on the back side of the operating surface, A measurement circuit for measuring the capacitance of each of the plurality of sensor electrodes, A calculation unit that calculates the position of an indicator based on a plurality of capacitances measured by the measurement circuit. Equipped with, The calculation unit described above, Based on the plurality of capacitances, the maximum capacitance between the indicator and the sensor electrode is calculated. Based on the maximum capacitance, a non-pointing determination threshold is set to determine whether the indicator is pointing or not. If the number of capacitances among the plurality of capacitances that exceed the non-pointing determination threshold exceeds the determination threshold, then the operation of the indicator is determined to be a non-pointing operation. Electrostatic coordinate input device.

2. The calculation unit sets a pointing determination threshold used to determine that the operation of the indicator is a pointing operation, based on the maximum capacitance. The electrostatic coordinate input device according to claim 1, wherein if the number of capacitances among the plurality of capacitances that exceed the pointing determination threshold is less than or equal to the determination threshold, the operation of the indicator is determined to be the pointing operation.

3. The calculation unit determines, based on the maximum capacitance, which of the multiple distance states the distance between the indicator and the operating surface corresponds to. The non-pointing detection threshold, the pointing detection threshold, and the detection count threshold are defined for each of the multiple distance states. The electrostatic coordinate input device according to claim 2, wherein the non-pointing determination threshold is set to a larger value the shorter the distance represented by the plurality of distance states.

4. The plurality of distance states include a contact state indicating that the operating surface and the indicator are in contact, and a plurality of non-contact states indicating that the operating surface and the indicator are not in contact. The non-pointing detection threshold in the contact state is greater than the non-pointing detection threshold in the plurality of non-contact states. The pointing detection threshold in the contact state is greater than the pointing detection threshold in the multiple non-contact states. The electrostatic coordinate input device according to claim 3, wherein the threshold for the number of determinations in the contact state is smaller than the threshold for the number of determinations in the plurality of non-contact states.

5. The pointing detection thresholds in the aforementioned multiple non-contact states are equal to each other. The electrostatic coordinate input device according to claim 4, wherein the threshold values ​​for the number of determinations in the plurality of non-contact states are equal to each other.

6. The threshold values ​​for the number of determinations in the aforementioned multiple non-contact states are equal to each other. The electrostatic coordinate input device according to claim 4, wherein the pointing determination threshold in the plurality of non-contact states is larger as the distance represented by the plurality of distance states decreases.

7. The pointing detection thresholds in the aforementioned multiple non-contact states are equal to each other. The electrostatic coordinate input device according to claim 4, wherein the threshold for the number of determinations in the plurality of non-contact states is smaller as the distance represented by the plurality of distance states decreases.

8. The electrostatic coordinate input device according to claim 4, wherein the shorter the distance represented by the plurality of distance states, the larger the pointing judgment threshold and the smaller the judgment count threshold.

9. The aforementioned multiple non-contact states are, in order from the shortest to the longest distance represented by the multiple distance states, a confirmed state in which the input content is confirmed, a selected state in which an input candidate is selected, a proximity state in which the input candidate is in close proximity, and a non-detection state in which the indicator is not detected. The non-pointing detection threshold in the non-detection state and the non-pointing detection threshold in the proximity state are the same value. The pointing detection threshold in the non-detection state and the pointing detection threshold in the proximity state are the same value. The electrostatic coordinate input device according to claim 4, wherein the threshold value for the number of determinations in the non-detection state and the threshold value for the number of determinations in the proximity state are the same value.

10. The electrostatic coordinate input device according to claim 2, wherein the non-pointing determination threshold is a value proportional to the maximum capacitance.

11. The aforementioned pointing detection threshold is a value proportional to the maximum capacitance. The electrostatic coordinate input device according to claim 10, wherein the pointing detection threshold is greater than the non-pointing detection threshold.

12. The electrostatic coordinate input device according to claim 10, wherein the threshold for the number of determinations is a value inversely proportional to the maximum capacitance.

13. The calculation unit described above, In a state where it is determined that the operation of the indicator is a pointing operation, if the number of capacitances exceeding the non-pointing determination threshold exceeds the determination threshold for a predetermined number of consecutive times, it is determined that the operation of the indicator is a non-pointing operation. In a state where it is determined that the operation of the indicator is a pointing operation, the operation of the indicator is determined to be a non-pointing operation until the number of capacitances exceeding the non-pointing determination threshold exceeds the determination threshold for a predetermined number of consecutive times. When it is determined that the operation of the indicator is a non-pointing operation, if the number of capacitances exceeding the pointing determination threshold is less than or equal to the determination threshold for a predetermined number of consecutive times, it is determined that the operation of the indicator is a pointing operation. The electrostatic coordinate input device according to any one of claims 2 to 12, wherein, in a state in which the operation of the indicator is determined to be a non-pointing operation, the operation of the indicator is determined to be a non-pointing operation until the number of capacitances exceeding the pointing determination threshold is less than or equal to the determination threshold for a predetermined number of consecutive times.

14. Further including a display unit, The electrostatic coordinate input device according to claim 13, wherein the calculation unit determines that the operation of the indicator is a non-pointing operation, and displays a message on the display unit requesting that the pointing operation be performed with the indicator.

15. The operating surface, Multiple sensor electrodes arranged on the back side of the operating surface, A measurement circuit for measuring the capacitance of each of the plurality of sensor electrodes, A calculation unit that calculates the position of an indicator based on a plurality of capacitances measured by the measurement circuit. An operation determination method for an electrostatic coordinate input device comprising: Based on the plurality of capacitances, the maximum capacitance between the indicator and the sensor electrode is calculated. Based on the maximum capacitance, a non-pointing determination threshold is set to determine whether the indicator is pointing or not. If the number of capacitances among the plurality of capacitances that exceed the non-pointing determination threshold exceeds the determination threshold, then the operation of the indicator is determined to be a non-pointing operation. Operation determination method for electrostatic coordinate input device.

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