JP2020010198A - Detection device - Google Patents

Abstract

To provide a detection device capable of detecting a disconnection in regard to a cancel electrode in an input device which can perform a cancel control.SOLUTION: A detection device comprises a detection part detecting a disconnection in regard to a cancel electrode in an input device which performs a control that includes a sensor electrode to which a driving signal is applied, the cancel electrode for reducing a parasitic capacitance between the sensor electrode and a reference potential point, and makes the sensor electrode to apply a driving signal, and a cancel control making the cancel electrode to apply a signal of a waveform similar to the driving signal. The detection part detects whether the disconnection in regard to the cancel electrode is generated on the basis of a first electrostatic capacity of the sensor electrode detected when both the control making the driving signal to apply and the cancel control are performed, and a second electrostatic capacitance of the sensor electrode detected when the control making the driving signal to apply is only performed.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a detection device.

  Techniques have been developed for preventing erroneous operation determination in a capacitive input device. As the above technique, for example, a technique described in Patent Document 1 can be mentioned.

JP 2018-37348 A

  The capacitance-type input device detects, for example, the capacitance of an electrode corresponding to an electrostatic sensor (electrostatic switch), and detects a change in the capacitance of the electrode caused by an operation by an operating body such as a finger. Thus, it is determined whether or not an operation is performed on the electrostatic sensor corresponding to the electrode. The change in the capacitance of the electrode is detected, for example, by comparing the detected capacitance of the electrode with a predetermined threshold.

  In a capacitance-type input device, a parasitic capacitance is generated between an electrode whose capacitance is to be detected (hereinafter, referred to as a “sensor electrode”) and a reference potential point (ground). The magnitude of the parasitic capacitance generated between the sensor electrode and the reference potential point depends on the area of the sensor electrode and the like.

  The parasitic capacitance generated between the sensor electrode and the reference potential point can be a noise in determining the operation of the electrostatic sensor corresponding to the sensor electrode. Therefore, the parasitic capacitance generated between the sensor electrode and the reference potential point is large. As a result, there is a disadvantage in SNR (Signal-to-Noise Ratio) characteristics and the like. Therefore, in order to improve the detection accuracy of the operation for the electrostatic sensor and prevent erroneous determination of the operation, it is desirable to further reduce the parasitic capacitance generated between the sensor electrode and the reference potential point.

  Here, for example, the input device described in Patent Document 1 includes a sensor electrode and a cancel electrode. The sensor electrode is an electrode to which a drive signal (voltage signal) for detecting an operation is applied, and the cancel electrode is an electrode for reducing a parasitic capacitance between the sensor electrode and a reference potential point. In the input device described in Patent Literature 1, control for applying a drive signal to a sensor electrode and cancel control for applying a signal (voltage signal) having the same waveform as the drive signal to a cancel electrode are performed.

  If a signal having the same waveform as the drive signal is applied to the cancel electrode when the drive signal is applied to the sensor electrode, the sensor electrode and the cancel electrode have the same potential. Therefore, in the above case, no parasitic capacitance occurs between the sensor electrode and the cancel electrode. Therefore, when a signal having the same waveform as the drive signal is applied to the cancel electrode when the drive signal is applied to the sensor electrode, for example, the parasitic capacitance between the sensor electrode and the reference potential point is reduced. It is possible to reduce it.

  Therefore, in a capacitance-type input device that performs cancel control, such as the input device described in Patent Document 1, the effect of “improving operation detection accuracy and preventing erroneous operation determination” can be achieved. Is played.

  Here, for example, when a signal having the same waveform as the drive signal cannot be applied to the cancel electrode due to disconnection, the cancel control cannot be performed. In this case, an input capable of performing the cancel control is performed. The device cannot achieve the above effects. Hereinafter, a disconnection in the signal line for applying a signal having the same waveform as the drive signal to the cancel electrode is referred to as “disconnection relating to the cancel electrode”.

  An object of the present invention is to provide a new and improved detection device capable of detecting a disconnection of a cancel electrode in an input device capable of performing cancel control.

  To achieve the above object, according to one aspect of the present invention, there is provided a sensor electrode to which a drive signal is applied, and a cancel electrode for reducing a parasitic capacitance between the sensor electrode and a reference potential point. In the input device where the control for applying the drive signal to the sensor electrode and the cancel control for applying a signal having the same waveform as the drive signal to the cancel electrode are performed, the disconnection of the cancel electrode is performed. A first capacitance of the sensor electrode, which is detected when both the control for applying the drive signal and the cancel control are performed, and the drive signal; Disconnection related to the cancel electrode based on the second capacitance of the sensor electrode detected when only the control for applying Occurs may detect that the detection device is provided.

  In such a configuration, by using the capacitances of the sensor electrodes respectively detected under different control conditions of the cancel electrode, disconnection of the cancel electrode occurs in a state in which the influence of the capacitance due to the operation and the capacitance of the substrate is eliminated. Can be detected. Therefore, with this configuration, it is possible to detect a disconnection related to the cancel electrode in the input device capable of performing the cancel control.

  Further, the detection unit compares the difference value between the second capacitance and the first capacitance with a set predetermined range, so that disconnection of the cancel electrode occurs. May be detected.

  Further, the detection unit may detect that the disconnection of the cancel electrode has occurred when the difference value is not included in the predetermined range.

  A switch unit having the sensor electrode and the cancel electrode; and a control unit performing control for applying the drive signal and cancel control. The detection unit further includes a capacitance of the sensor electrode. May be detected based on the change of the switch.

  According to the present invention, it is possible to detect disconnection of a cancel electrode in an input device capable of performing cancel control.

FIG. 4 is an explanatory diagram illustrating an example of a parasitic capacitance generated between a sensor electrode and a reference potential point GND in an input device in which cancel control is not performed. FIG. 4 is an explanatory diagram illustrating an example of a parasitic capacitance generated between a sensor electrode and a reference potential point GND in an input device on which cancel control is performed. FIG. 9 is an explanatory diagram for describing an example of a method for detecting disconnection. It is a block diagram showing an example of composition of a detecting device concerning an embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and the drawings, components having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted.

  Hereinafter, a parasitic capacitance generated between one object and another object is represented as “parasitic capacitance Csn” (n is a number for distinguishing the parasitic capacitance) using the reference symbol Cs. 1 and 2 showing the parasitic capacitance Csn, the magnitude relationship of the magnitude of the parasitic capacitance Csn is represented by two types of magnitudes of circuit symbols indicating capacitors for convenience.

[1] Cancel Control Before describing an example of a disconnection detection method for a cancel electrode according to an embodiment of the present invention and a configuration of a detection device capable of performing processing according to the detection method, cancel control will be described. I do.

  As described above, in a capacitance-type input device (hereinafter, simply referred to as “input device”), a parasitic capacitance is generated between the sensor electrode and the reference potential point.

  FIG. 1 is an explanatory diagram illustrating an example of a parasitic capacitance generated between a sensor electrode and a reference potential point GND in an input device in which cancel control is not performed. FIG. 1 shows an example in which the input device has two sensor electrodes represented by “sensor 1” and “sensor 2”.

The parasitic capacitances Cs1 and Cs2 shown in FIG. 1 are as follows, respectively. Note that the magnitude of the parasitic capacitances Cs1 and Cs2 depends on the area of the sensor electrode and the like.
-Parasitic capacitance Cs1: a parasitic capacitance generated between the sensor electrode represented by "sensor 1" and the reference potential point GND-Parasitic capacitance Cs2: a parasitic capacitance between the sensor electrode represented by "sensor 2" and the reference potential point GND Parasitic capacitance generated between

  As described above, the parasitic capacitances Cs1 and Cs2 can be noise in the determination of the operation on the electrostatic sensor corresponding to the sensor electrode.

  Here, as a method of reducing the influence of the parasitic capacitances Cs1 and Cs2 as shown in FIG. 1, for example, as in an input device described in Patent Document 1, "a cancel electrode is further provided in the input device and cancel control is performed. Method ".

  FIG. 2 is an explanatory diagram illustrating an example of a parasitic capacitance generated between the sensor electrode and the reference potential point GND in the input device in which the cancellation control is performed. FIG. 2 shows an example in which the input device has two sensor electrodes represented by “sensor 1” and “sensor 2” and one cancel electrode represented by “cancel”. .

  In FIG. 2, the cancel electrode represented by “cancel” reduces the parasitic capacitance between each of the sensor electrode represented by “sensor 1” and the sensor electrode represented by “sensor 2” and the reference potential point GND. This is a cancel electrode for causing the cancel electrode. The cancel electrode represented by “cancel” is, for example, as shown in FIG. 2, one cancel electrode corresponding to each of all the sensor electrodes of the input device, and is located between all the sensor electrodes and the reference potential point GND. Serves to reduce the parasitic capacitance in the device. In addition, the example of the cancel electrode according to the embodiment of the present invention is not limited to the example illustrated in FIG. 2, and may have any configuration capable of exhibiting the effect obtained by performing the cancel control. .

The parasitic capacitances Cs1 ', Cs2', and Cs3 shown in FIG. 2 are as follows, respectively.
-Parasitic capacitance Cs1 ': Parasitic capacitance generated between the sensor electrode represented by "sensor 1" and reference potential point GND-Parasitic capacitance Cs2': sensor electrode represented by "sensor 2" and reference potential point GND Parasitic capacitance Cs3: Parasitic capacitance generated between the cancel electrode represented by "cancel" and the reference potential point GND

  When the cancel control is performed on the cancel electrode, no parasitic capacitance is generated between each of the sensor electrodes represented by “sensor 1” and “sensor 2” and the cancel electrode.

  When the cancel control is performed on the cancel electrode shown in FIG. 2, the parasitic capacitance Cs3 between the cancel electrode and the reference potential point GND causes the parasitic capacitance between the sensor electrode and the reference potential point GND. Cs1 ′ and Cs2 ′ are smaller than the parasitic capacitances Cs1 and Cs2 shown in FIG.

  Therefore, as shown in FIG. 2, in the input device in which the cancellation control is performed, the operation detection accuracy can be improved, and the erroneous operation determination can be prevented.

[2] Method for detecting disconnection related to cancel electrode according to the embodiment of the present invention However, in the input device where cancel control is performed, if disconnection related to the cancel electrode occurs, cancel control cannot be performed. Therefore, there is a demand for a detection method capable of detecting disconnection of the cancel electrode.

  Here, as one method for detecting a disconnection, for example, a “method for detecting a change in current or a change in voltage in a detection target for detecting a disconnection” is given.

  FIG. 3 is an explanatory diagram illustrating an example of a method for detecting a disconnection. FIG. 3 illustrates an example in which both ends of a detection target for detecting a disconnection are connected to a processor that functions as a disconnection detector.

  When a disconnection occurs in the detection target, the current and voltage in the detection target change before the disconnection occurs. Therefore, disconnection in the detection target can be detected by detecting a change in current or a change in voltage in the detection target. That is, the processor shown in FIG. 3 can detect a disconnection in the detection target by detecting a change in current or a change in voltage in the detection target at point A in FIG.

  However, one method shown with reference to FIG. 3 cannot detect a disconnection in the detection target when the detection target is an open end. As shown in an example of the configuration of an input device in which cancel control is performed, which will be described later, the cancel electrode may be an open end. Therefore, it is not always possible to detect “disconnection regarding the cancel electrode” using the method shown with reference to FIG.

  As another method of detecting a disconnection, for example, a “method of determining a disconnection in a detection target based on a change in capacitance detected by an input device” can be considered.

  However, for example, when an operation is performed on the input device, the capacitance detected by the input device is not only a parasitic capacitance but also a capacitance generated by an operation on the input device (hereinafter, referred to as “operation capacitance”). It also changes by. Therefore, it is difficult to determine the disconnection in the detection target simply by using the fluctuation of the capacitance.

  Therefore, the detection device according to the embodiment of the present invention (hereinafter, may be simply referred to as a “detection device”) is “when both control for applying a drive signal to the sensor electrode and cancellation control are performed. The disconnection related to the cancel electrode is determined based on the “capacitance of the sensor electrode” detected at the time when “the capacitance of the sensor electrode is detected only when the control for applying the drive signal is performed”. Detect if it has occurred. That is, the detection device detects whether or not the disconnection of the cancel electrode has occurred by using the capacitance of the sensor electrode detected under the control conditions of the two different cancel electrodes.

  Hereinafter, control for applying a drive signal to the sensor electrode is referred to as “operation detection control”. Hereinafter, the capacitance of the sensor electrode detected when both the operation detection control and the cancel control are performed is referred to as “first capacitance”, and only when the operation detection control is performed. The capacitance of the sensor electrode detected in the above is indicated as “second capacitance”.

  Hereinafter, specifically, a process related to a method of detecting a disconnection of the cancel electrode in the detection device will be described.

  The detection device detects whether the disconnection of the cancel electrode has occurred by using a difference value between the second capacitance and the first capacitance (hereinafter, may be simply referred to as a “difference value”). I do.

  Assuming that the first capacitance is “Ca”, the first capacitance is represented by Equation 1 below. “Cp” shown in the following Equation 1 is the capacitance of the substrate on which each electrode is provided. “Cs” shown in Expression 1 below is a parasitic capacitance when both the operation detection control and the cancel control are performed. “Cf” shown in the following Expression 1 is an operation capacity.

Ca = Cp + Cs + Cf
... (Formula 1)

  When the second capacitance is “Cb”, the second capacitance is represented by the following equation (2). “Cp” shown in Expression 2 below is the capacitance of the substrate on which each electrode is provided. “Cs0” shown in Expression 2 below is a parasitic capacitance when only the operation detection control is performed. “Cf” shown in Expression 2 below is the operation capacity.

Cb = Cp + Cs0 + Cf
... (Formula 2)

  From Expressions 1 and 2, the difference between the second capacitance and the first capacitance is represented by Expression 3 below.

Cb-Ca = Cs0-Cs
... (Formula 3)

  Here, the following equation 4 holds between the parasitic capacitance Cs when both the operation detection control and the cancel control are performed and the parasitic capacitance Cs0 when only the operation detection control is performed. Here, “A” shown in Equation 4 is a fixed value (0 <0) that is determined according to, for example, the material of the electrode (the sensor electrode and the cancel electrode) and the size of the electrode when there is no disconnection regarding the cancel electrode. A <1).

Cs = A · Cs0
... (Equation 4)

  From Expressions 3 and 4, the difference between the second capacitance and the first capacitance is expressed by Expression 5 below.

Cb-Ca = Cs0-Cs = Cs0-A.Cs0 = (1-A) .Cs0
... (Equation 5)

  Here, when no disconnection occurs with respect to the cancel electrode, “A” shown in the above Equation 5 is a fixed value.

  On the other hand, when a disconnection occurs with respect to the cancel electrode, “A” shown in the above Expression 5 does not become a fixed value. Therefore, when a disconnection occurs with respect to the cancel electrode, the change in the difference value represented by Expression 5 becomes large.

  Therefore, the detection device detects whether the disconnection of the cancel electrode has occurred by comparing the difference value with the set predetermined range.

  The detecting device detects that the disconnection of the cancel electrode has occurred when the difference value is not included in the predetermined range. Here, the predetermined range according to the embodiment of the present invention includes, for example, a fixed range set at the time of designing the input device. Note that the predetermined range may be a variable range that can be changed by an operation of a user of the detection device or the like.

  For example, when the difference value is equal to or smaller than the lower limit value of the predetermined range, or when the difference value is equal to or larger than the upper limit value of the predetermined range, the detection device detects that the disconnection of the cancel electrode has occurred. Further, for example, when the difference value is smaller than the lower limit value of the predetermined range, or when the difference value is larger than the upper limit value of the predetermined range, the detection device may detect that the disconnection of the cancel electrode has occurred. Good. Needless to say, the handling of the boundary value of the predetermined range in determining whether the difference value is included in the predetermined range is not limited to the above example.

  Further, when the difference value falls within the predetermined range, the detection device does not detect that the disconnection of the cancel electrode has occurred. In addition, the detection device may determine that the input device is normal when the difference value falls within a predetermined range.

  For example, when the difference value is larger than the lower limit value of the predetermined range and the difference value is smaller than the upper limit value of the predetermined range, the detection device does not detect that the disconnection of the cancel electrode has occurred. Further, for example, when the difference value is equal to or more than the lower limit value of the predetermined range and the difference value is equal to or less than the upper limit value of the predetermined range, the detection device detects that the disconnection of the cancel electrode has occurred. It is not necessary. Needless to say, the handling of the boundary value of the predetermined range in determining whether the difference value is included in the predetermined range is not limited to the above example.

  As described above, the detection device uses the difference value between the second capacitance Cb and the first capacitance Ca to detect whether or not the disconnection of the cancel electrode has occurred.

  Here, as shown in Equation 3, by taking the difference between the second capacitance Cb and the first capacitance Ca, the influence of the substrate capacitance Cp and the operation capacitance Cf is eliminated. Therefore, the detection device can detect whether or not the disconnection of the cancel electrode has occurred by checking the influence of the disconnection of the cancel electrode in the input device in a state where the influence of the substrate capacitance Cp and the operation capacitance Cf has been eliminated. it can. In addition, since it is possible to detect whether or not the disconnection of the cancel electrode has occurred in a state where the influence of the operation capacity Cf has been eliminated, the detection device can detect the disconnection of the cancel electrode even when the operation is performed. It is possible to detect whether a disconnection has occurred.

  Further, the effect of the disconnection on the cancel electrode appears as a change in a difference value between the second capacitance Cb and the first capacitance Ca. Therefore, the “method of detecting a disconnection related to the cancel electrode by comparing the difference value obtained by the above formula 5 with a predetermined range”, that is, the detection method according to the embodiment of the present invention, causes a disconnection related to the cancel electrode. It can be said that this is an effective method for detecting the presence or absence.

  Furthermore, in the detection method according to the embodiment of the present invention, it is detected whether or not the disconnection of the cancel electrode has occurred by using the difference value between the second capacitance Cb and the first capacitance Ca. The present invention can be applied to a case where the target is an open end.

  Therefore, the detection device using the detection method according to the embodiment of the present invention can detect the disconnection of the cancel electrode in the input device capable of performing the cancel control.

[3] Configuration Example of Detection Device According to Embodiment of the Present Invention Hereinafter, an example of the configuration of the detection device according to the embodiment of the present invention to which the above-described detection method according to the embodiment of the present invention can be applied. explain.

  Hereinafter, a case where the detection device according to the embodiment of the present invention is an input device having a sensor electrode and a cancel electrode and has a function of detecting a disconnection of the cancel electrode in the self will be described as an example. Note that the detection device according to the embodiment of the present invention is not limited to the input device. For example, the detection device according to the embodiment of the present invention may be configured to detect a disconnection of the cancel electrode in an external input device. Further, the detection device according to the embodiment of the present invention may have a function and a configuration according to an application example of the detection device described later.

  In addition, hereinafter, for convenience, a case where the detection device according to the embodiment of the present invention includes two sensor electrodes and one cancel electrode will be described as an example. It is needless to say that the number of sensor electrodes included in the detection device according to the embodiment of the present invention and the number of cancel electrodes included in the detection device according to the embodiment of the present invention are not limited to the following examples.

  FIG. 4 is a block diagram illustrating an example of a configuration of the detection device 100 according to the embodiment of the present invention. The detection device 100 includes, for example, a switch unit 102, a detection unit 104, a switching unit 106, and a control unit 108.

  The detection device 100 may include, for example, a ROM (Read Only Memory; not shown), a RAM (Random Access Memory; not shown), a storage unit (not shown), and the like. The detection device 100 connects the above-described components by, for example, a bus as a data transmission path. The detection device 100 is driven by, for example, power supplied from an internal power supply such as a battery included in the detection device 100 or power supplied from a connected external power supply.

  The ROM (not shown) stores, for example, data such as programs and calculation parameters used by the control unit 108 and a processing circuit 114 described later. The RAM (not shown) temporarily stores programs executed by the control unit 108, the processing circuit 114, and the like, processing data, and the like.

  The storage unit (not shown) is a storage unit included in the detection device 100. The storage unit (not shown) stores various data such as data related to the detection method of the present invention, such as data indicating a predetermined range, and application software.

  Here, examples of the storage unit (not shown) include a magnetic recording medium such as a hard disk and a recording medium such as a nonvolatile memory such as a flash memory. Further, the storage unit (not shown) may be detachable from the detection device 100.

[3-1] Switch section 102
The switch unit 102 has a plurality of sensor electrodes E1 and E2 and one cancel electrode CC.

  The sensor electrodes E1 and E2 are electrodes whose capacitance is to be detected by the detection unit 104. A drive signal is applied to each of the sensor electrodes E1 and E2 from, for example, a voltage source 110 described later.

  The cancel electrode CC is provided to reduce the parasitic capacitance between each of the sensor electrodes E1 and E2 and the reference potential point. The cancel electrode CC is, for example, one cancel electrode corresponding to each of all sensor electrodes included in the detection device 100, like the cancel electrode illustrated in FIG. The cancel electrode CC is provided, for example, in parallel with the sensor electrodes E1 and E2 via a base. The example of the cancel electrode included in the detection device 100 is not limited to the example illustrated in FIG. 4, and the cancel control is performed. Any configuration that can achieve the effect to be achieved may be used.

  As described above, by applying a signal having the same waveform as the drive signal applied to the sensor electrodes E1 and E2 to the cancel electrode CC, the parasitic capacitance between each of the sensor electrodes E1 and E2 and the reference potential point is reduced. ,Decrease.

  FIG. 4 illustrates an example of “a configuration in which the cancel electrode CC is electrically connected to the voltage source 110 by the switching unit 106 described later, and the drive signal itself is applied to the cancel electrode CC as a signal having the same waveform as the drive signal”. It is shown. FIG. 4 shows an example of “a configuration in which a cancel electrode CC is electrically connected to a reference potential point by a switching unit 106 described later”. That is, the cancel electrode CC shown in FIG. 4 functions as, for example, an electrode provided to reduce the parasitic capacitance between the sensor electrodes E1 and E2 and the reference potential point, or a reference electrode connected to the reference potential point. I do.

  Note that the configuration of the switch unit 102 included in the detection device 100 according to the embodiment of the present invention is not limited to the example illustrated in FIG.

  For example, in the switch unit 102, the cancel electrode and the reference electrode may be separate electrodes.

[3-2] Detection unit 104
The detection unit 104 performs a process related to the method for detecting a disconnection related to the cancel electrode according to the embodiment of the present invention, and detects a disconnection related to the cancel electrode CC. The detection unit 104 transmits, for example, data indicating the detection result of the disconnection regarding the cancel electrode CC to the control unit 108. Note that the detection unit 104 may transmit data indicating a detection result to the control unit 108 when a disconnection regarding the cancel electrode CC is detected.

  The detection unit 104 detects the capacitance of each of the sensor electrodes E1 and E2 by a self-capacitance method. The detection unit 104 sets the sensor electrode to which the drive signal is applied as a detection target of the capacitance. As the capacitance of each of the sensor electrodes E1 and E2 detected by the detection unit 104, only the first capacitance detected when both the operation detection control and the cancellation control are performed, and only the operation detection control Second capacitance detected when the operation is being performed ”.

  The detection unit 104 detects whether the disconnection of the cancel electrode CC has occurred, for example, based on the first capacitance of the sensor electrode E1 and the second capacitance of the sensor electrode E1. Further, the detection unit 104 may detect whether or not the disconnection of the cancel electrode CC has occurred based on the first capacitance of the sensor electrode E2 and the second capacitance of the sensor electrode E2.

  The detecting unit 104 detects an operation on the switch unit 102 based on a change in the capacitance of each of the sensor electrodes E1 and E2.

  The detection unit 104 sets, for example, a sensor electrode to which a drive signal is applied as a sensor electrode to be detected as an operation. Then, the detection unit 104 compares the detected capacitance with a predetermined threshold that has been set, so that an operation is performed on the electrostatic sensor corresponding to the sensor electrode included in the switch unit 102. Detect that. Examples of the capacitance to be compared with the predetermined threshold include a first capacitance detected when both the operation detection control and the cancel control are performed. In the following, “the operation has been performed on the electrostatic sensor corresponding to the sensor electrode included in the switch unit 102”, which is detected by the detection unit 104, indicates that “the operation has been performed on the switch unit 102. That ".

  Here, the predetermined threshold value according to the embodiment of the present invention may be a fixed threshold value that is set in advance, or may be a variable threshold value that changes based on an operation detection result of the detection unit 104 or the like. Good. As an example of the variable threshold based on the detection result of the operation, for example, “when an operation is detected by the detection unit 104, the threshold is set to be smaller than the threshold set before the operation is detected by the detection unit 104. , A smaller value is set. "

  The capacitance of the sensor electrodes E1 and E2 changes, for example, when an operating body such as a finger approaches the sensor electrodes E1 and E2. The detection unit 104 detects an operation on the switch unit 102 by detecting a change in the capacitance of each of the sensor electrodes E1 and E2 by performing the threshold process using the predetermined threshold as described above.

  Specifically, for example, when the detected capacitance is equal to or more than a predetermined threshold (or when the capacitance is larger than the predetermined threshold), the detection unit 104 Detects that an operation has been performed.

  Further, for example, when an operation on the switch unit 102 is detected, the detection unit 104 determines that the operation on the switch unit 102 has been performed.

  Note that the method of determining the operation of the switch unit 102 by the detection unit 104 is not limited to the above. For example, when the operation is detected a predetermined number of times, the detection unit 104 can also determine that the operation on the switch unit 102 has been performed. The predetermined number of times according to the embodiment of the present invention may be a fixed number of times set in advance, or may be a variable number of times that can be changed based on a command from the control unit 108 or an external controller. .

  As described above, the detection unit 104 determines that the operation on the switch unit 102 has been performed when the operation has been detected a predetermined number of times, thereby further reducing the possibility that an erroneous determination of the operation on the switch unit 102 occurs. can do.

  The detection unit 104 includes, for example, a voltage source 110, measurement circuits 112A and 112B, a processing circuit 114, switching circuits SW1, SW2, SW3, SW4, SW5, SW6, and ground capacitors C1 and C2.

  The voltage source 110 outputs a drive signal (voltage signal) for driving the sensor electrodes E1 and E2. Note that the voltage source 110 may be a voltage source external to the detection device 100.

  The measurement circuits 112A and 112B detect the capacitance (self-capacitance value) by, for example, measuring the charging time of the capacitance. The measurement circuit 112A is electrically connected to the sensor electrode E1 via the switching circuit SW2, and detects the capacitance of the sensor electrode E1. The measurement circuit 112B is electrically connected to the sensor electrode E2 via the switching circuit SW5, and detects the capacitance of the sensor electrode E2.

  The measuring circuits 112A and 112B detect the capacitance by measuring the charging time of the capacitance using, for example, one or two or more comparators, and calculating the capacitance value from the measured charging time.

  Note that the measurement circuits 112A and 112B are not limited to the examples described above. The measurement circuits 112A and 112B can have a configuration corresponding to any method capable of measuring capacitance.

  The processing circuit 114 performs a process related to the disconnection detection method for the cancel electrode according to the embodiment of the present invention, and detects a disconnection for the cancel electrode CC. The processing circuit 114 determines whether the disconnection of the cancel electrode CC has occurred based on the capacitance of the sensor electrode E1 detected by the measurement circuit 112A or the capacitance of the sensor electrode E2 detected by the measurement circuit 112B. Is detected.

  Further, the processing circuit 114 detects an operation on the switch unit 102 based on the capacitance of the sensor electrodes E1 and E2 detected by the measurement circuits 112A and 112B, respectively. The processing circuit 114 detects an operation on the electrostatic sensor corresponding to the sensor electrode E1, for example, by comparing the detected capacitance of the sensor electrode E1 with a predetermined threshold. Further, the processing circuit 114 detects an operation on the electrostatic sensor corresponding to the sensor electrode E2, for example, by comparing the detected capacitance of the sensor electrode E2 with a predetermined threshold.

  Further, as described above, the processing circuit 114 may determine whether or not an operation has been performed on the switch unit 102 based on the detection result of the operation on the switch unit 102 and the predetermined number of times.

  The processing circuit 114 includes, for example, one or two or more processors configured by an arithmetic circuit such as a CPU (Central Processing Unit).

  Each of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 is formed of, for example, a switching transistor, and is turned on (conducting state) or off (non-conducting state) in accordance with the signal level (voltage level) of an applied signal. ).

  Examples of the switching transistor include a bipolar transistor and an FET (Field-Effect Transistor) such as a TFT (Thin Film Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

  The control of switching between the ON state and the OFF state of each of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 is performed by, for example, a control unit 108 described later.

  The switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 are not limited to switching transistors, and may be any elements (or circuits) that can switch between an on state and an off state.

  In the detection unit 104, for example, as shown in the following (a) and (b), the switching state of each of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 is switched, so that the static state of the sensor electrode E1 is switched. The detection of the capacitance and the detection of the capacitance of the sensor electrode E2 are sequentially performed.

(A) When detecting the capacitance of the sensor electrode E1-Switching circuits SW1, SW2: ON state-Switching circuits SW3, SW4, SW5, SW6: OFF state

(B) When detecting the capacitance of the sensor electrode E2-Switching circuits SW4, SW5: ON state-Switching circuits SW1, SW2, SW3, SW6: OFF state

  For example, by performing on / off control of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 as shown in the above (a) and (b), the detection unit 104 causes the sensor electrodes E1 and E2 to be connected to the respective sensors. Driving signals are sequentially applied thereto, and the capacitances (self-capacitance values) of the sensor electrodes E1 and E2 are sequentially detected in the measurement circuits 112A and 112B.

  The switching circuits SW3 and SW6 are switching circuits for initializing the measurement of the capacitance.

  For example, the switching of the switching circuits SW1, SW2, and SW3 between the on state and the off state as shown in (c) below initializes the measurement of the capacitance of the sensor electrode E1. Here, the on / off control of the switching circuits SW1, SW2, and SW3 shown in (c) below does not detect the capacitance of the sensor electrode E1, for example, when detecting the capacitance of the sensor electrode E2. When done.

(C) When Initializing Measurement of Sensor Electrode E1 Switching Circuits SW2 and SW3: ON State Switching Circuit SW1: OFF State

  Further, for example, as shown in (d) below, the switching state of each of the switching circuits SW4, SW5, and SW6 is switched to initialize the measurement of the capacitance of the sensor electrode E2. Here, the on / off control of the switching circuits SW4, SW5, and SW6 shown in (d) below does not detect the capacitance of the sensor electrode E2, for example, when detecting the capacitance of the sensor electrode E1. When done.

(D) When initializing the measurement of the sensor electrode E2 ・ Switching circuits SW5 and SW6: ON state ・ Switching circuit SW4: OFF state

  The ground capacitance C1, for example, is connected between the sensor electrode E1 and the switching circuit SW2. The ground capacitance C1 may be a parasitic capacitance or a circuit element such as a capacitor.

  The ground capacitance C2 is connected, for example, between the sensor electrode E2 and the switching circuit SW5. The ground capacitance C2 may be a parasitic capacitance or a circuit element such as a capacitor.

  The detection unit 104 performs a process related to the method for detecting a disconnection related to the cancel electrode according to the embodiment of the present invention, and detects a disconnection related to the cancel electrode CC according to the configuration illustrated in FIG. 4, for example. Further, the detecting unit 104 detects the capacitance (self-capacitance value) of each of the sensor electrodes E1 and E2 by the configuration shown in FIG. 4, for example, and based on the change in the capacitance of the sensor electrodes E1 and E2, the switch unit 102. Detect operations on.

  Note that the configuration of the detection unit 104 is not limited to the example illustrated in FIG.

  For example, the detection unit 104 can have any configuration capable of measuring the capacitance (self-capacitance value) of each of the sensor electrodes E1 and E2.

  Further, for example, when the control unit 108 described below has a function of performing the same processing as the processing circuit 114, the detection unit 104 may not include the processing circuit 114.

  The detection unit 104 sequentially detects the capacitance of each of the plurality of sensor electrodes E1 and E2. Therefore, the detection unit 104 may be configured to include one measurement circuit corresponding to the plurality of sensor electrodes E1 and E2.

[3-3] Switching unit 106
The switching unit 106 includes a switching circuit including switching circuits SW7 and SW8, and the switching circuit is electrically connected to the cancel electrode CC.

  The switching circuits SW7 and SW8 are configured by, for example, switching transistors, and are turned on (conducting state) or off (non-conducting state) according to the signal level (voltage level) of the applied signal.

  Note that the switching circuits SW7 and SW8 are not limited to switching transistors, and may be arbitrary elements (or circuits) that can switch between an on state and an off state.

  When each of the switching circuits SW7 and SW8 is turned on (conducting state) or off (non-conducting state), the cancel electrode CC is connected to the voltage source 110 or the reference potential point.

In the switching unit 106, for example, the ON state and the OFF state of each of the switching circuits SW7 and SW8 are switched as described below, so that the cancel electrode CC is connected to the voltage source 110 and is not connected to the reference potential point. Here, a state in which the cancel electrode CC is connected to the voltage source 110 corresponds to a state in which cancel control is performed on the cancel electrode CC.
Switching circuit SW7: ON state Switching circuit SW8: OFF state

Further, in the switching unit 106, for example, the ON state and the OFF state of each of the switching circuits SW7 and SW8 are switched as described below, so that the cancel electrode CC is connected to the reference potential point and is not connected to the voltage source 110. Here, a state where the cancel electrode CC is not connected to the voltage source 110 corresponds to a state where the cancel control is not performed on the cancel electrode CC.
-Switching circuit SW7: OFF state-Switching circuit SW8: ON state

  The switching between the ON state and the OFF state of each of the switching circuits SW7 and SW8 is performed by, for example, the control unit 108.

  The configuration of the switching unit 106 is not limited to the example illustrated in FIG. For example, the switching unit 106 can have any configuration that allows the cancel electrode CC to be connected to one of the voltage source 110 and the reference potential point. Further, the switching unit 106 may be a part of the detection unit 104.

[3-4] Control unit 108
The control unit 108 performs control on the sensor electrode and control on the cancel electrode.

  The control unit 108 includes, for example, one or more processors, various processing circuits, and the like, which are configured by an arithmetic circuit such as a CPU.

[3-4-1] Control for Sensor Electrode in Control Unit 108 As described above, the control unit 108 performs operation detection control (control for applying a drive signal to the sensor electrode) as control for a plurality of sensor electrodes. Do.

  The control unit 108 transmits a signal for switching between an ON state and an OFF state to each of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 included in the detection unit 104, for example. Drive signals are sequentially applied to the electrodes.

  In addition, the control unit 108 transmits a control signal including an instruction to switch the ON state and the OFF state of each switching circuit to the processing circuit 114 included in the detection unit 104, for example, to transmit the control signal to the plurality of sensor electrodes. A drive signal may be sequentially applied thereto. When the control unit 108 transmits a control signal to the processing circuit 114, the detection unit 104 determines that “the processing circuit 114 sends the control signal to each of the switching circuits SW1, SW2, SW3, SW4, SW5, and SW6 based on the transmitted control signal. On the other hand, by transmitting a signal for switching between the ON state and the OFF state, the sequential application of the drive signal to the plurality of sensor electrodes is realized.

[3-4-2] Control on Cancel Electrode in Control Unit 108 The control unit 108 performs cancel control on the cancel electrode CC when, for example, a drive signal is applied to any of the sensor electrodes. , The parasitic capacitance between all the sensor electrodes E1 and E2 and the reference potential point is reduced.

  The control unit 108 does not perform the cancel control when the drive signal is not applied to the plurality of sensor electrodes E1 and E2.

  The control unit 108 selectively performs the cancel control on the cancel electrode CC by transmitting a signal for switching between an ON state and an OFF state to each of the switching circuits SW7 and SW8 included in the switching unit 106, for example. .

  Note that the control by the control unit 108 is not limited to the example described above. For example, the control unit 108 can perform control according to the configuration of the cancel electrode included in the switch unit 102 (control capable of realizing cancel control).

  Further, the processing in the control unit 108 is not limited to the processing related to the control on the sensor electrode and the processing related to the control on the cancel electrode.

  For example, the control unit 108 may perform processing based on data indicating a disconnection detection result regarding the cancel electrode CC transmitted from the detection unit 104.

  As an example of the process based on the data indicating the detection result, there is a “notification process of notifying that an abnormality has occurred in the input device (in the example illustrated in FIG. 4, the detection device 100 corresponds)”. The control unit 108 visually notifies that an abnormality has occurred, for example, by turning on a lamp or displaying an image or a character string on a display screen of a display device. In addition, the control unit 108 may output an audio (including music) from an audio output device such as a speaker, or the like, to audibly notify that an abnormality has occurred.

  The example of the process based on the data indicating the detection result is not limited to the above notification process. For example, the control unit 108 may control the communication device to transmit data indicating the detection result of the disconnection regarding the cancel electrode CC to an external device such as a server.

  As described above, the control unit 108 may have a function of performing the same processing as the processing circuit 114. The control unit 108 may also serve to control the entire detection device 100.

  The detection device 100 has, for example, a configuration illustrated in FIG.

  In the detection device 100, the detection unit 104 detects a disconnection related to the cancel electrode CC by performing a process related to the disconnection detection method related to the cancel electrode according to the embodiment of the present invention.

  Therefore, the detecting device 100 detects the disconnection of the cancel electrode CC in the input device capable of performing the cancel control (in the example shown in FIG. 4, the detecting device 100 corresponds) by the configuration shown in FIG. Can be.

  Note that the configuration of the detection device according to the embodiment of the present invention is not limited to the configuration illustrated in FIG.

  For example, FIG. 4 shows a configuration in which the detection device functions as an input device. However, the detection device according to the embodiment of the present invention may be configured to detect a disconnection of the cancel electrode in an external input device. In a detection device having a configuration for detecting a disconnection related to a cancel electrode in an external input device, a disconnection related to the cancel electrode in the input device is detected based on the capacitance detected in the external input device. As an example, as a detection device having a configuration for detecting a disconnection related to a cancel electrode in an external input device, at least “a detection device having a function of performing a process related to a method for detecting a disconnection related to a cancel electrode according to an embodiment of the present invention. Unit ".

[4] Application Example of Detection Device According to Embodiment of the Present Invention The detection device according to the embodiment of the present invention is applied to a vehicle system such as a vehicle such as a car (or a UI (User Interface) part configuring the vehicle system). Various systems and devices, including communication devices such as mobile phones and smartphones, tablet devices, computers such as PCs (Personal Computers), and capacitive input devices such as ATMs (Automated Teller Machines). Can be applied to The detection device according to the embodiment of the present invention is, for example, a device separate from the above-described system or device (a device for detecting a disconnection of the cancel electrode in the above-described system or device). You may.

[5] Program according to an embodiment of the present invention A program for causing a computer to function as the detection device according to the embodiment of the present invention. By executing the program for execution by a processor or the like in a computer, it is possible to detect a disconnection related to a cancel electrode in an input device capable of performing cancel control.

  Further, a program for causing a computer to function as the detection device according to the embodiment of the present invention is executed by a processor or the like in the computer, whereby the disconnection detection method for the cancel electrode according to the above-described embodiment of the present invention is implemented. The effect obtained by performing such processing can be achieved.

  As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious that those skilled in the art can conceive various changes or modifications within the scope of the claims, and these naturally belong to the technical scope of the present invention. I understand.

  For example, while the above description has shown that a program (computer program) for causing a computer to function as the detection device according to the embodiment of the present invention is provided, the embodiment of the present invention further stores the program. A recorded medium can also be provided. Examples of the recording medium storing the program include “a recording medium included in a device that functions as a detection device according to an embodiment of the present invention, such as a recording medium that functions as a storage unit (not shown)”, and “ A recording medium external to the device, which can read the program, by a device functioning as the detection device according to the embodiment of the present invention.

Reference Signs List 100 detection device, 102 switch unit, 104 detection unit, 106 switching unit, 108 control unit, E1, E2 sensor electrode, CC cancel electrode, GND Reference potential point

Claims (4)

A sensor electrode to which a drive signal is applied, and a cancel electrode for reducing a parasitic capacitance between the sensor electrode and a reference potential point; control to apply the drive signal to the sensor electrode; An input device in which cancellation control for applying a signal having the same waveform as the drive signal to the cancellation electrode is performed, further comprising a detection unit that detects a break in the cancellation electrode.
The detection unit performs only the first capacitance of the sensor electrode, which is detected when both the control for applying the drive signal and the cancel control are performed, and the control for applying the drive signal. A detection device that detects whether or not a disconnection has occurred with respect to the cancel electrode, based on the second capacitance of the sensor electrode that is detected when the sensor electrode is disconnected.   The detection unit compares a difference value between the second capacitance and the first capacitance with a set predetermined range to determine whether the disconnection of the cancel electrode has occurred. The detection device according to claim 1, which detects.   The detection device according to claim 2, wherein the detection unit detects that the disconnection of the cancel electrode has occurred when the difference value is not included in the predetermined range. A switch unit having the sensor electrode and the cancel electrode,
A control unit that performs the control for applying the drive signal and the cancel control,
With
The detection device according to any one of claims 1 to 3, wherein the detection unit further detects an operation on the switch unit based on a change in capacitance of the sensor electrode.

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