JP7200056B2 - Touch sensors, controllers, and computer programs - Google Patents

Description

The present invention relates to touch sensors. The present invention also relates to a control device that can be mounted on the touch sensor and a computer program that causes the control device to perform a predetermined operation.

Patent Literature 1 discloses a capacitive touch sensor. In the touch sensor, when a user's finger or the like approaches an object positioned within the electric field generated by the electrodes, a pseudo capacitor is formed and the capacitance of the electrodes themselves increases. By detecting this increase in capacity, it is determined whether or not the user has performed an operation on the object.

JP 2018-188822 A

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to accurately determine an operation on an object even in a noisy environment.

One aspect for achieving the above object is a touch sensor,
an electrode;
a capacitance detection unit that detects the capacitance between the electrode and the object as a detection capacitance at a predetermined cycle;
a control unit that determines whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
and
The control unit
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
Setting a capacitance range based on the reference capacitance before stopping updating,
When the detected capacitance is within the capacitance range, updating the reference capacitance with the detected capacitance.

One aspect for achieving the above object is a control device that controls the operation of a capacitance detection unit that detects the capacitance between an electrode and an object as a detection capacitance at a predetermined cycle, ,
determining whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
Setting a capacitance range based on the reference capacitance before stopping updating,
When the detected capacitance is within the capacitance range, updating the reference capacitance with the detected capacitance.

One aspect for achieving the above object is a computer program that causes a control device to control the operation of a capacitance detection unit that detects the capacitance between an electrode and an object as a detection capacitance at a predetermined cycle. and
By executing the computer program, the control device
determining whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
setting a capacitance range based on the reference capacitance before the update is stopped;
When the detected capacitance is within the capacitance range, updating the reference capacitance with the detected capacitance.

According to each of the above aspects, when the detected capacitance is smaller than the reference capacitance and the difference between the two is greater than a predetermined value, updating of the reference capacitance is stopped, and updating of the detected capacitance is stopped. Updating the reference capacitance is not restarted until it is within the capacitance range set based on the previous reference capacitance. In other words, while it is considered that the influence of environmental noise on the detection capacitance is large, it is unlikely that it will be determined that the object has been manipulated based on the decreased detection capacitance. It can suppress the occurrence. Therefore, it is possible to accurately determine the operation on the object even in a noisy environment.

According to the present invention, it is possible to accurately discriminate an operation on an object even in a noisy environment.

1 illustrates a functional configuration of a touch sensor according to one embodiment; 4 shows the principle of operation of the above touch sensor. An example of the flow of operation of the above touch sensor is shown. An example of the flow of operation of the above touch sensor is shown. 4 illustrates the operation of the touch sensor described above.

Exemplary embodiments are described in detail below with reference to the accompanying drawings. FIG. 1 illustrates the functional configuration of a touch sensor 1 according to one embodiment.

The touch sensor 1 includes electrodes 11 . The electrode 11 is arranged so that a part of the user's body (such as the finger F) faces the object 2 on which a touch operation can be performed. Object 2 is a dielectric. The term “touch operation” used in this specification means an operation involving the approach or contact of a part of the user's body with respect to the object 2 .

The touch sensor 1 includes a capacitance detection section 12 . The capacitance detection unit 12 has a charging/discharging circuit 121 for detecting the capacitance between the electrode 11 and the object 2 .

The charge/discharge circuit 121 is electrically connected to the electrode 11 . The charging/discharging circuit 121 can perform charging and discharging operations. During the charging operation, the charging/discharging circuit 121 supplies the electrode 11 with a current supplied from a power source (not shown). During the discharge operation, the charge/discharge circuit 121 releases current from the electrode 11 .

An electric field is generated around the object 2 by the current supplied to the electrode 11 . When the user's finger F or the like approaches this electric field, a pseudo capacitor is formed between it and the electrode 11 . This increases the capacitance between the electrode 11 and the object 2 . As the capacitance increases, the current emitted from the electrode 11 increases during the discharge operation.

The touch sensor 1 has a control device 13 . The control device 13 includes a control section 131 . The control unit 131 has a function of controlling the operation of the charging/discharging circuit 121 . Control unit 131 operates charging/discharging circuit 121 at a predetermined frequency. The expression "operate the charging/discharging circuit at a predetermined frequency" used in this specification means to cause the charging/discharging circuit to repeat charging and discharging operations at a predetermined frequency.

The capacitance detection unit 12 has a conversion circuit 122 . A current emitted from the electrode 11 is input to the conversion circuit 122 . The conversion circuit 122 includes a circuit whose transmission frequency changes according to the amount of input current, and a counter that counts pulses output from the circuit. That is, the conversion circuit 122 outputs data having a numerical value corresponding to the amount of current corresponding to the detected capacitance.

The data is input to the control unit 131 . The controller 131 can acquire the capacitance between the electrode 11 and the object 2 based on the numerical value indicated by the data. In this way, the controller 131 causes the capacitance detector 12 to detect the capacitance between the electrode 11 and the object 2 .

As illustrated in FIG. 2, the control unit 131 also has a function of determining whether a touch operation has been performed on the object 2 based on the capacitance detected by the capacitance detection unit 12. . Specifically, the control unit 131 causes the capacitance detection unit 12 to repeatedly detect the capacitance between the electrode 11 and the object 2 at a predetermined cycle T. FIG. A period T is, for example, 20 milliseconds. In the following description, the capacitance between the electrode 11 and the object 2 detected by the capacitance detector 12 is called "detected capacitance C".

When the user's finger F or the like approaches the object 2, the capacitance between the electrode 11 and the object 2 increases as described above. The control unit 131 determines that a touch operation has been performed on the object 2 when the amount of increase from the reference capacitance Cr exceeds a predetermined threshold value Cth. In the illustrated example, it is determined that the touch operation was performed from time t1 to time t2.

As shown in FIG. 1 , the control device 13 has a storage section 132 . The storage unit 132 stores data corresponding to the reference capacitance Cr. Control unit 131 compares the data input from conversion circuit 122 corresponding to the detected capacitance with the data stored in storage unit 132 to determine whether the touch operation has been performed. .

FIG. 2 shows the reference capacitance Cr as if it were a constant value. However, the reference capacitance Cr is updated with the obtained detected capacitance C value. The flow of a series of processes by the control unit 131 will be described with reference to FIGS. 3 and 4. FIG.

The control unit 131 acquires the detected capacitance C (STEP 1). Specifically, numerical data corresponding to the detected capacitance C is received from the conversion circuit 122 .

Subsequently, it is determined whether a touch operation has been performed on the object 2 . First, the controller 131 determines whether the detected capacitance C is lower than the reference capacitance Cr (STEP 2). Specifically, the determination is made by comparing the data input from the conversion circuit 122 and the data stored in the storage unit 132 . This determination is made to distinguish whether the change in the detected capacitance C is caused by a touch operation or environmental noise. A phenomenon in which the detected capacitance C exceeds the reference capacitance Cr is generally caused by a touch operation. On the other hand, the phenomenon in which the detected capacitance C exceeds the reference capacitance Cr is generally due to environmental noise.

When it is determined that the detected capacitance C is not less than the reference capacitance Cr (NO in STEP 2), the controller 131 determines that the amount of increase in the detected capacitance C from the reference capacitance Cr reaches a predetermined threshold value. It is determined whether or not Cth is exceeded (STEP 3). Specifically, the determination is made by comparing the data input from the conversion circuit 122 and the data stored in the storage unit 132 .

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr is equal to or less than the predetermined threshold value Cth (NO in STEP 3), the control unit 131 performs the touch operation on the object 2. judge that it is not. In this case, the control unit 131 updates the numerical data corresponding to the reference capacitance Cr stored in the storage unit 132 with the numerical data corresponding to the detected capacitance C (STEP 4). That is, the detected capacitance C becomes the new reference capacitance Cr. The process returns to STEP 1, and after a lapse of time corresponding to the predetermined period T, the next detected capacitance C is obtained.

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr exceeds the predetermined threshold value Cth (YES in STEP 3), the control unit 131 performs the touch operation on the object 2. (STEP 5). In this case, as illustrated in FIG. 1, control unit 131 outputs detection signal S indicating that a touch operation has been performed. Also in this case, the control section 131 updates the numerical data corresponding to the reference capacitance Cr stored in the storage section 132 with the numerical data corresponding to the detected capacitance C (STEP 4). That is, the detected capacitance C becomes the new reference capacitance Cr. The process returns to STEP 1, and after a lapse of time corresponding to the predetermined period T, the next detected capacitance C is acquired.

When it is determined that the detected capacitance C is lower than the reference capacitance Cr (YES in STEP2), environmental noise countermeasure processing is started. The control unit 131 determines whether the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds a predetermined threshold value Cth (STEP 6). Specifically, the determination is made by comparing the data input from the conversion circuit 122 and the data stored in the storage unit 132 . Note that the threshold Cth used in STEP6 and the threshold Cth used in STEP3 are not necessarily the same.

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr is equal to or less than the predetermined threshold value Cth (NO in STEP 6), the control unit 131 determines that the influence of environmental noise is small, and detects The numerical data corresponding to the reference capacitance Cr stored in the storage unit 132 is updated with the numerical data corresponding to the capacitance C (STEP 4). That is, the detected capacitance C becomes the new reference capacitance Cr. The process returns to STEP 1, and after a lapse of time corresponding to the predetermined period T, the next detected capacitance C is acquired.

When it is determined that the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the predetermined threshold value Cth (YES in STEP 6), the control unit 131 determines that the influence of environmental noise is large, The updating of the reference capacitance Cr by the detected capacitance C is stopped (STEP7). The control unit 131 starts counting the elapsed time Te from when the update is stopped.

Further, the control unit 131 determines whether or not the elapsed time Te from when the update of the reference capacitance Cr is stopped is equal to or greater than a predetermined threshold value Tth (STEP 8). In other words, it is determined whether the suspension of updating the reference capacitance Cr has continued for a predetermined length of time. When it is determined that the elapsed time Te is less than the predetermined threshold value Tth (NO in STEP8), the process returns to STEP1, and after the time corresponding to the predetermined period T elapses, the next detected capacitance C is acquired. be.

When it is determined that the elapsed time Te exceeds the predetermined threshold value Tth (YES in STEP 9), the control unit 131 sets the capacitance range γ based on the reference capacitance Cr before the update is stopped ( STEP9). A range γ is defined as the range of the detected capacitance C assumed when the influence of environmental noise is eliminated. For example, it is set within a range of ±20% of the value of the reference capacitance Cr stored in the storage unit 132 . Note that the setting of the range γ may be performed together with the stopping of updating the reference capacitance Cr (STEP 7).

Subsequently, the control unit 131 acquires the next detected capacitance C after a lapse of time corresponding to the predetermined cycle T (STEP 11). Since this process is the same as STEP 1, repetitive description will be omitted.

Subsequently, the control unit 131 determines whether the detected capacitance C is lower than the reference capacitance Cr (STEP 12). Since this process is the same as STEP 2, repetitive description will be omitted.

When it is determined that the detected capacitance C is not less than the reference capacitance Cr (NO in STEP 12), the controller 131 determines that the amount of increase in the detected capacitance C from the reference capacitance Cr reaches a predetermined threshold value. It is determined whether or not Cth is exceeded (STEP 13).

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr is equal to or less than the predetermined threshold value Cth (NO in STEP 13), the control unit 131 performs the touch operation on the object 2. It is judged that there is no significant change in the noise environment. The process returns to STEP11 while the update of the reference capacitance Cr is stopped, and the next detected capacitance C is obtained after the time corresponding to the predetermined cycle T has elapsed.

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr exceeds the predetermined threshold value Cth (YES in STEP 13), the control unit 131 determines that the acquired detected capacitance C is increased in STEP 9. (STEP 14).

When it is determined that the acquired detected capacitance C is within the range γ (YES in STEP 14), the control unit 131 converts the numerical data corresponding to the detected capacitance C to the reference stored in the storage unit 132. Numerical data corresponding to the capacitance Cr is updated (STEP 15). That is, the detected capacitance C becomes the new reference capacitance Cr. The process returns to STEP 1, and after a lapse of time corresponding to the predetermined period T, the next detected capacitance C is obtained.

When it is determined that the acquired detected capacitance C is not within range γ (NO in STEP 14), control unit 131 determines that a touch operation has been performed on object 2 (STEP 16). In this case, control unit 131 outputs detection signal S indicating that the touch operation has been performed. Also in this case, the control unit 131 updates the numerical data corresponding to the reference capacitance Cr stored in the storage unit 132 with the numerical data corresponding to the detected capacitance C (STEP 15). That is, the detected capacitance C becomes the new reference capacitance Cr. The process returns to STEP 1, and after a lapse of time corresponding to the predetermined period T, the next detected capacitance C is acquired.

If it is determined that the detected electrostatic capacitance C is lower than the reference electrostatic capacitance Cr (YES in STEP 12), the controller 131 determines that the amount of decrease in the detected electrostatic capacitance C from the reference electrostatic capacitance Cr reaches a predetermined threshold value. It is determined whether or not Cth is exceeded (STEP 17).

When it is determined that the amount of increase in the detected capacitance C from the reference capacitance Cr is equal to or less than the predetermined threshold value Cth (NO in STEP 17), the control unit 131 performs the touch operation on the object 2. It is judged that there is no significant change in the noise environment. The process returns to STEP11 while the update of the reference capacitance Cr is stopped, and the next detected capacitance C is obtained after the time corresponding to the predetermined cycle T has elapsed.

When it is determined that the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the predetermined threshold value Cth (YES in STEP 17), the control unit 131 determines that the influence of environmental noise is large. Start counting the elapsed time Te.

Further, the control unit 131 determines whether or not the elapsed time Te from when the update of the reference capacitance Cr is stopped is equal to or greater than a predetermined threshold value Tth (STEP 18). In other words, it is determined whether the period in which the influence of environmental noise is large continues for a predetermined length of time. When it is determined that the elapsed time Te is less than the predetermined threshold value Tth (NO in STEP 18), the process returns to STEP 11, and after the time corresponding to the predetermined period T elapses, the next detected capacitance C is acquired. be.

When it is determined that the elapsed time Te exceeds the predetermined threshold value Tth (YES in STEP 18), the control unit 131 adjusts the capacitance range γ based on the detected capacitance at the start of counting the elapsed time Te. Reset (STEP 19). The range γ is defined as the range of detected capacitance C expected when the effects of the latest environmental noise are eliminated. For example, it is set within a range of ±20% of the value of the detected capacitance at the start of counting the elapsed time Te. Note that the setting of the range γ may be performed at the same time as the counting of the elapsed time Te is started. After that, the process returns to STEP 11, and the next detected capacitance C is obtained after the time corresponding to the predetermined cycle T has passed.

An operation example of the touch sensor 1 configured as described above will be described with reference to FIG. In FIG. 5, the black circles represent the detected capacitance C acquired at each predetermined period T. In FIG. A white circle represents the reference capacitance Cr referred to when the detected capacitance C is obtained.

The detected capacitance C acquired at time t1 is smaller than the reference capacitance Cr at that time (corresponding to YES in STEP2 of FIG. 3). Therefore, it is determined whether the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP 6 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr at time t1 does not exceed the threshold value Cth (corresponding to NO in STEP6 in FIG. 3). Therefore, the reference capacitance Cr is updated by the detected capacitance C obtained at time t1 (corresponding to STEP4 in FIG. 3). That is, the detected capacitance C obtained at time t1 becomes the reference capacitance Cr for the detected capacitance C obtained at time t2 after the time corresponding to the predetermined cycle T has elapsed.

The detected capacitance C acquired at time t2 is smaller than the reference capacitance Cr at that time (corresponding to YES in STEP2 of FIG. 3). Therefore, it is determined whether the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP 6 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr obtained at time t2 exceeds the threshold Cth (corresponding to YES in STEP6 in FIG. 3). Therefore, updating of the reference capacitance Cr is stopped (corresponding to STEP7 in FIG. 3).

After that, every time the time corresponding to the predetermined cycle T elapses, the acquisition of the detected capacitance C is repeated (corresponding to STEP 1 in FIG. 3). Each time the detected capacitance C is obtained, it is determined whether or not the elapsed time Te from the stop of updating the reference capacitance Cr is equal to or greater than a predetermined threshold value Tth (corresponding to STEP8 in FIG. 3).

In the example shown in FIG. 5, the elapsed time Te reaches the threshold Tth at time t3 (corresponding to YES in STEP8 of FIG. 3). Therefore, the capacitance range γ is set based on the reference capacitance Cr at time t3 before the update is stopped (corresponding to STEP9 in FIG. 3).

After that, every time the time corresponding to the predetermined cycle T elapses, the acquisition of the detected capacitance C is repeated. Each time the detected capacitance C is acquired, it is determined whether the value is within the range γ (corresponding to the flow from STEP 12 to STEP 14 in FIG. 4).

In the example shown in FIG. 5, the detected capacitance C acquired at time t5 is within the range γ (corresponding to YES in STEP 14 of FIG. 4). Therefore, the reference capacitance Cr is updated by the detected capacitance C acquired at time t5 (corresponding to STEP15 in FIG. 4). That is, the detected capacitance C obtained at time t5 becomes the reference capacitance Cr for the detected capacitance C obtained at time t6 after the time corresponding to the predetermined cycle T has elapsed.

The detected capacitance C obtained at time t6 is larger than the reference capacitance Cr at that time (corresponding to NO in STEP2 in FIG. 3). Therefore, it is determined whether the amount of increase in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP 3 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr acquired at time t6 does not exceed the threshold Cth (corresponding to NO in STEP2 in FIG. 3). Therefore, the reference capacitance Cr is updated with the detected capacitance C acquired at time t6 (corresponding to STEP4 in FIG. 3). That is, the detected capacitance C obtained at time t6 becomes the reference capacitance Cr for the detected capacitance C obtained at time t7 after the time corresponding to the predetermined cycle T has elapsed.

The detected capacitance C acquired at time t7 is larger than the reference capacitance Cr at that time (corresponding to NO in STEP2 in FIG. 3). Therefore, it is determined whether the amount of increase in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP 3 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr obtained at time t7 exceeds the threshold Cth (corresponding to YES in STEP3 of FIG. 3). Therefore, it is determined that a touch operation has been performed on the object 2 (corresponding to STEP 5 in FIG. 3).

Advantages of the configuration as described above will be described. A triangular mark indicated at a point corresponding to time t5 in FIG. 5 represents, as a comparative example, the reference capacitance Cr that is referred to at that time when the update of the reference capacitance is continued. That is, the reference capacitance Cr at time t5 corresponds to the reference capacitance C acquired at time t4 immediately before that.

The amount of increase in the detected capacitance C obtained at time t5 from the detected capacitance C obtained at time t4 exceeds the threshold value Cth. Therefore, it is determined that the touch operation on the object 2 has been performed, even though the increase in the detection capacitance C is within the influence of the environmental noise.

In this embodiment, when the detected capacitance C is smaller than the reference capacitance Cr and the difference between the two is greater than the threshold value Cth, updating of the reference capacitance Cr is stopped, and the detection capacitance C is updated. The updating of the reference capacitance Cr is not restarted until the capacitance falls within the range γ of the capacitance set based on the reference capacitance Cr before stopping. In other words, while the influence of environmental noise on the detected capacitance C is considered to be large, a situation occurs in which it is determined that a touch operation has been performed based on the decreased detected capacitance C. can be suppressed. Therefore, it is possible to accurately determine a touch operation even in an environmental noise environment.

The touch sensor 1 having the configuration as described above can be incorporated in, for example, a door handle that is a part of a vehicle. A door handle is an example of an object. In this case, when it is determined that the user's finger F or the like has touched the door handle, the control device 13 outputs the detection signal S. FIG. The detection signal S can be sent to, for example, a vehicle door lock. The locking device can lock and unlock the door according to the detection signal S.

The functions of the control unit 131 described above can be implemented by a dedicated integrated circuit such as a microcontroller, ASIC, or FPGA that can execute a computer program that implements the processes described above. The controller 131 may be realized by a general-purpose microprocessor operating in cooperation with a general-purpose memory. A CPU, MPU, and GPU can be exemplified as a general-purpose microprocessor. Examples of general-purpose memory include ROM and RAM. In this case, the ROM may store a computer program for executing the above-described process. The general-purpose microprocessor designates at least part of the program stored on the ROM, develops it on the RAM, and cooperates with the RAM to execute the above-described processing. The controller 131 may be implemented by a combination of a general-purpose microprocessor and a dedicated integrated circuit.

The functions of the storage unit 132 described above can be realized by a storage device such as a semiconductor memory or a hard disk device. At least part of the general-purpose memory described above may be used as the storage unit 132 . The control unit 131 and the storage unit 132 may be provided as a plurality of elements independent of each other, or may be packaged in a single element.

The above embodiments are merely examples for facilitating understanding of the present invention. The configurations according to the above embodiments can be modified and improved as appropriate without departing from the scope of the present invention.

As exemplified in FIG. 3, when the state in which the update of the reference capacitance Cr is stopped continues for a predetermined length of time (YES in STEP 8), the control unit 131 controls the detection acquired at that point in time. A reset update may be performed to update the numerical data corresponding to the reference capacitance Cr stored in the storage unit 132 with the numerical data corresponding to the capacitance C (STEP 10). By resetting the value of the reference capacitance Cr to a value adapted to the environment under the condition that the noise environment continues for a certain period of time, the detection accuracy of the touch operation performed under the environment can be improved. A similar process may be performed when time elapses in STEP18 of FIG.

In the above-described embodiment, the capacitance range γ for canceling the suspension of update of the reference capacitance Cr has an upper limit value and a lower limit value. The range γ may be defined only by the lower limit value, but by setting the upper limit value, the detection accuracy of the touch operation in STEP 16 can be improved.

The touch sensor 1 can be arranged at locations other than the door handle in the vehicle. A touch operation detected by touch sensor 1 does not necessarily have to be performed with finger F of the user. Touch operations using body parts such as palms, elbows, knees, and toes can also be detected.

The touch sensor 1 can be used for any user interface that requires detection of a touch operation by a user. Examples of devices equipped with such a user interface include building air-conditioning equipment, building light control equipment, audio-visual equipment used indoors or outdoors, cooking equipment, air-conditioning equipment, toys, and the like.

1: touch sensor, 2: object, 11: electrode, 12: capacitance detection unit, 13: control device, 131: control unit, C: detection capacitance, Cr: reference capacitance, Cth: threshold, Te: Elapsed time from stop of update of reference capacitance, Tth: threshold, γ: range of capacitance

Claims (5)

an electrode;
a capacitance detection unit that detects the capacitance between the electrode and the object as a detection capacitance at a predetermined cycle;
a control unit that determines whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
and
The control unit
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
Setting a range of capacitance based on the reference capacitance before update stop,
updating the reference capacitance with the detected capacitance when the detected capacitance is within the range of the capacitance;
touch sensor. The capacitance range is ±20% of the reference capacitance.
The touch sensor according to claim 1. the object is part of a vehicle,
The touch sensor according to claim 1 or 2. A control device that controls the operation of a capacitance detection unit that detects the capacitance between an electrode and an object as a detection capacitance in a predetermined cycle,
determining whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
Setting a range of capacitance based on the reference capacitance before update stop,
updating the reference capacitance with the detected capacitance when the detected capacitance is within the range of the capacitance;
Control device. A computer program that causes a control device to control the operation of a capacitance detection unit that detects the capacitance between an electrode and an object as a detection capacitance at a predetermined cycle,
By executing the computer program, the control device
determining whether or not the object is operated based on the difference between the detected capacitance and the reference capacitance;
updating the reference capacitance with the detection capacitance;
stopping updating the reference capacitance when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value;
setting a capacitance range based on the reference capacitance before the update is stopped;
updating the reference capacitance with the detected capacitance when the detected capacitance is within the range of the capacitance;
computer program.

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