JP7196026B2 - 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.

A first 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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period,
When it is determined that the update of the reference capacitance for the first period has been stopped, the update of the reference capacitance is stopped for a third period shorter than the second period.

A second 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 in a predetermined cycle. hand,
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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period,
When it is determined that the update of the reference capacitance for the first period has been stopped, the update of the reference capacitance is stopped for a third period shorter than the second period.

A third aspect for achieving the above object is a computer 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. a program,
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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
If the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period;
When it is determined that the update of the reference capacitance for the first period has been stopped, the update of the reference capacitance is stopped for a third period shorter than the second period,
computer program.

If the detected capacitance increased by the operation on the object is taken as the reference capacitance, even if a large detected capacitance is obtained by subsequent operations, the difference from the reference capacitance will become small, and the object will There is a risk that the fact that the operation to has been performed may not be properly determined. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

A phenomenon in which the detected capacitance falls below the reference capacitance is generally the effect of environmental noise. Therefore, when the detected capacitance is smaller than the reference capacitance and the difference between the two is larger than a predetermined value, it is expected that environmental noise is acting on the touch sensor. In this case, the control unit does not determine that an operation has been performed on the object, and stops updating the reference capacitance as environmental noise countermeasure processing. If the detected capacitance that has decreased due to environmental noise is used as the reference capacitance, even if the detected capacitance is smaller than when an operation is performed, if the difference from the reference capacitance is large, the operation There is a possibility that it is erroneously recognized as having been performed. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

On the other hand, the cause of the phenomenon that the amount of decrease in the detection capacitance becomes larger than the predetermined value is the influence of the environmental noise described above, and the first period of time while the user's finger or the like is in contact with the object. It is conceivable that it expires and the updating of the reference capacitance is restarted. In this case, the detected capacitance obtained after resuming the update takes the value in the state in which the operation has been performed, and this value is used as the reference capacitance. Therefore, the environmental noise countermeasure processing is activated based on the detected capacitance that rapidly decreases when the user's finger or the like moves away from the object.

By determining whether the update of the reference capacitance for the first period has been stopped, the control unit determines whether the phenomenon in which the amount of decrease in the detected capacitance is greater than a predetermined value is caused by environmental noise. It identifies whether it is due to maintenance of the operation state. Since updating of the reference capacitance in the first period is stopped when it is determined that an operation has been performed on the target object, the amount of decrease in the detected capacitance is less than the predetermined value immediately after the updating is stopped. When the phenomenon of increasing the size occurs, there is a high possibility that the phenomenon is caused by the maintenance of the operating state.

Therefore, when it is determined that the update of the reference capacitance for the first period has not been stopped, the control unit stops the update of the reference capacitance for the second period as a countermeasure against environmental noise. On the other hand, when it is determined that the updating of the reference capacitance for the first period has been stopped, the control unit stops updating the reference capacitance for a third period shorter than the second period. The reason why the third period is shorter than the second period is to avoid continuation of the environmental noise countermeasure processing under circumstances not caused by environmental noise, and to quickly return to the normal state where the operation on the object can be detected. is.

A fourth 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;
If it is determined that the operation has not been performed for the first period, stop acquiring the detected capacitance and perform a calibration process;
if the sensed capacitance is less than the reference capacitance and the difference is greater than a first predetermined value, whether the increase in capacitance occurring during the calibration process exceeds a second predetermined value; to judge
when it is determined that the increase in the capacitance does not exceed the second predetermined value, stopping updating the reference capacitance for a second period;
When it is determined that the increase in the capacitance exceeds the second predetermined value, updating the reference capacitance is stopped for a third period shorter than the second period.

A fifth 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. hand,
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;
If it is determined that the operation has not been performed for the first period, stop acquiring the detected capacitance and perform a calibration process;
if the sensed capacitance is less than the reference capacitance and the difference is greater than a first predetermined value, whether the increase in capacitance occurring during the calibration process exceeds a second predetermined value; to judge
when it is determined that the increase in the capacitance does not exceed the second predetermined value, stopping updating the reference capacitance for a second period;
When it is determined that the increase in the capacitance exceeds the second predetermined value, updating the reference capacitance is stopped for a third period shorter than the second period.

A sixth aspect for achieving the above object is a computer 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. a program,
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;
If it is determined that the operation has not been performed for the first period, stop acquiring the detected capacitance and perform a calibration process;
if the sensed capacitance is less than the reference capacitance and the difference is greater than a first predetermined value, whether the increase in capacitance occurring during the calibration process exceeds a second predetermined value; to judge
when it is determined that the increase in the capacitance does not exceed the second predetermined value, stopping updating the reference capacitance for a second period;
When it is determined that the increase in the capacitance exceeds the second predetermined value, updating of the reference capacitance is stopped for a third period shorter than the second period.

If the detected capacitance increased by the operation to the object is taken as the reference capacitance, even if a large detected capacitance is obtained by the subsequent operation, the difference from the reference capacitance becomes small, and the target There is a risk that the fact that an object has been manipulated may not be properly determined. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

A phenomenon in which the detected capacitance falls below the reference capacitance is generally the effect of environmental noise. Therefore, when the detected capacitance is smaller than the reference capacitance and the difference between the two is larger than a predetermined value, it is expected that environmental noise is acting on the touch sensor. In this case, the control unit does not determine that an operation has been performed on the object, and stops updating the reference capacitance as environmental noise countermeasure processing. If the detected capacitance that has decreased due to environmental noise is taken as the reference capacitance, even if the detected capacitance that is smaller than that obtained when the operation is performed is large, if the difference from the reference capacitance is large, the operation There is a possibility that it is erroneously recognized as having been performed. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

On the other hand, the cause of the phenomenon that the amount of decrease in the detected capacitance becomes larger than the predetermined value is that, in addition to the environmental noise mentioned above, the user's finger or the like is still in contact with the object when the calibration process ends. , the update of the reference capacitance may be restarted. In this case, the detected capacitance obtained after resuming the update takes the value in the state in which the operation has been performed, and this value is used as the reference capacitance. Therefore, the environmental noise countermeasure processing is activated based on the detected capacitance that rapidly decreases when the user's finger or the like moves away from the object.

By determining whether the detected capacitance has increased rapidly during the update process, the control unit determines whether environmental noise is the cause of the phenomenon in which the amount of decrease in the detected capacitance exceeds a predetermined value. It identifies whether it is due to the operation inside. The update process is executed when it is determined that no operation has been performed for a predetermined period of time. If a phenomenon occurs in which the amount of decrease exceeds the second predetermined value, it is highly likely that the phenomenon is caused by manipulation during the calibration process.

Therefore, when it is determined that the amount of increase in capacitance that occurred during the calibration process is equal to or less than the second predetermined value, the control unit stops updating the reference capacitance for the second period as a countermeasure against environmental noise. On the other hand, if it is determined that the amount of increase in capacitance that occurred during the calibration process is greater than the second predetermined value, the control unit stops updating the reference capacitance for a third period that is shorter than the second period. . The reason why the third period is shorter than the second period is to avoid continuation of the environmental noise countermeasure processing under circumstances not caused by environmental noise, and to quickly return to the normal state where the operation on the object can be detected. is.

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. 4 illustrates the operation of a touch sensor according to the flow of FIG. 3; 4 shows another example of the flow of operation of the touch sensor described above. 4 shows another example of the flow of operation of the touch sensor described above. 7 illustrates the operation of a touch sensor according to the flows of FIGS. 5 and 6. FIG.

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. That is, the reference capacitance Cr is a value of capacitance that serves as a reference for determining whether a touch operation has been performed on the object 2 based on the detected capacitance. 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. An example of the flow of processing by the control unit 131 will be described with reference to FIG.

The control unit 131 acquires the detected capacitance C (STEP 1). Specifically, the control unit 131 receives numerical data corresponding to the detected capacitance C 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 exceeds 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 .

When it is determined that the detected electrostatic capacitance C exceeds the reference electrostatic capacitance Cr (YES in STEP 2), the controller 131 determines that the amount of increase 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 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.

Furthermore, the control unit 131 stops updating the reference capacitance Cr and continues acquiring the detected capacitance C at predetermined intervals T (STEP 6).

Subsequently, the control unit 131 determines whether the first period T1 has passed since the update was stopped (STEP7). The control unit 131 repeats acquisition of the detected capacitance C at each predetermined cycle T without updating the reference capacitance Cr until it is determined that the first period T1 has passed (NO in STEP7).

When it is determined that the first period T1 has elapsed since the updating of the reference capacitance Cr was stopped (YES in STEP7), the control section 131 turns the value of the identification flag to the ON state (STEP8). The role of the identification flag will be described later. The identification flag is a storage area capable of storing at least 1-bit information referenced by the control unit 131 . The storage area may be provided by memory or registers.

Subsequently, 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 latest detected capacitance C (STEP 4). That is, the latest 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.

That is, when the detected capacitance C is greater than the reference capacitance Cr and the difference between the two is greater than a predetermined threshold value Cth, the control unit 131 stops updating the reference capacitance Cr for the first period T1. . In other words, when it is determined that a touch operation has been performed on the object 2, updating of the reference capacitance Cr is stopped only for the first period T1.

If the detected capacitance C increased by the touch operation is taken as the reference capacitance Cr, even if a large detected capacitance C is obtained by subsequent touch operations, the difference from the reference capacitance Cr becomes small. There is a risk that the fact that a touch operation has been performed may not be properly determined. According to the configuration as described above, it is possible to suppress the occurrence of such a situation. Therefore, the length of the first period T1 can be determined based on the assumed duration of the touch operation.

When it is determined that the detected capacitance C does not exceed the reference capacitance Cr (NO in STEP 2), the controller 131 determines that the amount of decrease 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 9). 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 STEP 3 and the threshold Cth used in STEP 9 are not necessarily the same.

When it is determined that the amount of decrease in the detected capacitance C from the reference capacitance Cr is equal to or less than the predetermined threshold value Cth (NO in STEP 9), the control unit 131 converts numerical data corresponding to the detected capacitance C to Numerical data corresponding to the reference capacitance Cr stored in the storage unit 132 is updated (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 decrease in the detected capacitance C from the reference capacitance Cr exceeds the predetermined threshold value Cth (YES in STEP 9), the control unit 131 determines whether the value of the identification flag is ON. (STEP 10).

When it is determined that the value of the identification flag is not ON (NO in STEP 10), the control unit 131 stops updating the reference capacitance Cr and continues acquiring the detected capacitance C at each predetermined cycle T. (STEP 11).

Subsequently, the control unit 131 determines whether the second period T2 has passed since the update was stopped (STEP 12). The control unit 131 repeats acquisition of the detected capacitance for each predetermined cycle T without updating the reference capacitance Cr until it is determined that the second period T2 has elapsed (NO in STEP12).

When it is determined that the second period T2 has elapsed since the updating of the reference capacitance Cr was stopped (YES in STEP 12), the control unit 131 stores numerical data corresponding to the latest detected capacitance C in the storage unit 132. Numerical data corresponding to the reference capacitance Cr that has been set is updated (STEP 4). That is, the latest 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.

On the other hand, when it is determined that the value of the identification flag is ON (YES in STEP 10), the control unit 131 stops updating the reference capacitance Cr, and changes the detected capacitance C every predetermined cycle T. Acquisition is continued (STEP 13).

Subsequently, the control unit 131 determines whether or not the third period T3 has elapsed since the update was stopped (STEP 14). The third period T3 is shorter than the second period T2. The control unit 131 repeats acquisition of the detected capacitance for each predetermined period T without updating the reference capacitance Cr until it is determined that the third period T3 has passed (NO in STEP14).

When it is determined that the third period T3 has passed since the update of the reference capacitance Cr was stopped (YES in STEP 14), the control unit 131 stores numerical data corresponding to the latest detected capacitance C in the storage unit 132. Numerical data corresponding to the reference capacitance Cr that has been set is updated (STEP 4). That is, the latest 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. At that time, the value of the identification flag is reset to the OFF state.

A phenomenon in which the detected capacitance C falls below the reference capacitance Cr is generally due to environmental noise. Therefore, when the detected capacitance C is smaller than the reference capacitance Cr and the difference between them is larger than the predetermined threshold value Cth, it is expected that environmental noise is acting on the touch sensor 1 . In this case, the control unit 131 does not determine that the touch operation has been performed on the object 2, and stops updating the reference capacitance Cr as the environmental noise countermeasure processing.

If the detected capacitance C that has decreased due to environmental noise is used as the reference capacitance Cr, even if a detected capacitance C that is smaller than when a touch operation is performed is obtained, the difference between the detected capacitance C and the reference capacitance Cr is reduced. If the difference is large, there is a possibility that the touch operation is erroneously recognized. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

On the other hand, the phenomenon that the amount of decrease in the detected capacitance C becomes larger than the predetermined threshold value Cth is caused by, in addition to the influence of the environmental noise, a state in which the user's finger F or the like is in contact with the object 2. , the first period T1 expires, and the update of the reference capacitance Cr is restarted. In this case, the detected capacitance C obtained after resuming the update takes the value in the state where the touch operation is performed, and this value is used as the reference capacitance Cr. Therefore, based on the detected capacitance C that rapidly decreases when the user's finger F or the like moves away from the object 2, the environmental noise countermeasure processing is activated.

The control unit 131 refers to the identification flag that is turned ON when the update is stopped during the first period T1, thereby causing a phenomenon in which the amount of decrease in the detected electrostatic capacitance C becomes larger than the predetermined threshold value Cth. It identifies whether the cause is environmental noise or the maintenance of the touch state. That is, when the detected capacitance C is smaller than the reference capacitance Cr and the difference between the two is greater than the predetermined threshold value Cth, the control unit 131 stops updating the reference capacitance Cr in the first period T1. determine whether or not The identification flag is turned ON when it is determined that a touch operation has been performed. Therefore, when a phenomenon occurs in which the amount of decrease in the detected capacitance C becomes larger than the predetermined threshold value Cth while the identification flag is in the ON state, there is a high possibility that the phenomenon is caused by maintaining the touch state.

Therefore, when it is determined that the update of the reference capacitance Cr has not been stopped in the first period T1, the control unit 131 stops the update of the reference capacitance Cr only in the second period T2 as an environmental noise countermeasure. The length of the second period T2 may be determined based on the expected duration of environmental noise.

On the other hand, when it is determined that the updating of the reference capacitance Cr for the first period T1 has been stopped, the control unit 131 stops updating the reference capacitance Cr for a third period T3 shorter than the second period T2. . The reason why the third period T3 is shorter than the second period T2 is to avoid continuation of the environmental noise countermeasure processing under circumstances not caused by environmental noise, and to quickly return to a normal state in which touch operations can be detected. be.

According to the configuration as described above, it is possible to accurately determine a touch operation even in a noisy environment.

An operation example of the touch sensor 1 configured as shown in FIG. 3 will be described with reference to FIG. In FIG. 4, 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 greater than the reference capacitance Cr at that time (corresponding to YES in STEP2 of 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 at time t1 does not exceed the threshold value Cth (corresponding to NO in STEP2 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 greater than the reference capacitance Cr at that time (corresponding to YES in STEP2 of FIG. 3). Therefore, it is determined whether or not the amount of increase 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 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).

In this case, the updating of the reference capacitance Cr is stopped, and the acquisition of the detected capacitance C is repeated each time the time corresponding to the predetermined cycle T elapses (corresponding to STEP 6 in FIG. 3). Each time the detected capacitance C is acquired, it is determined whether the first period T1 has passed since the update of the reference capacitance Cr was stopped (corresponding to STEP7 in FIG. 3).

In this example, the first period T1 expires at time t6 (corresponding to YES in STEP7 of FIG. 3). Therefore, the identification flag is turned ON (corresponding to STEP8 in FIG. 3), and the reference capacitance Cr is updated by the detected capacitance C obtained 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 smaller than the reference capacitance Cr at that time (corresponding to NO in STEP2 in FIG. 3). Therefore, it is determined whether or not the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP9 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr acquired at time t7 does not exceed the threshold value Cth (corresponding to NO in STEP9 in FIG. 3). Therefore, the reference capacitance Cr is updated by the detected capacitance C acquired at time t7 (corresponding to STEP4 in FIG. 3). That is, the detected capacitance C obtained at time t7 becomes the reference capacitance Cr for the detected capacitance C obtained at time t8 after the time corresponding to the predetermined cycle T has elapsed. Also, the identification flag is reset and turned off.

The detected capacitance C acquired at time t8 is smaller than the reference capacitance Cr at that time (corresponding to NO in STEP2 in FIG. 3). Therefore, it is determined whether or not the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP9 in FIG. 3).

In this example, the difference between the detected capacitance C and the reference capacitance Cr obtained at time t8 exceeds the threshold Cth (corresponding to YES in STEP9 of FIG. 3). Therefore, it is determined whether the identification flag is ON (corresponding to STEP 10 in FIG. 3).

In this example, the identification flag is reset at time t7, so it is not in the ON state (corresponding to NO in STEP10 in FIG. 3). Therefore, the rapid drop in the detected capacitance C is determined to be the effect of environmental noise. In this case, the updating of the reference capacitance Cr is stopped, and the acquisition of the detected capacitance C is repeated every time the time corresponding to the predetermined period T elapses (corresponding to STEP 11 in FIG. 3). Each time the detected capacitance C is obtained, it is determined whether the second period T2 has elapsed since the update of the reference capacitance Cr was stopped (corresponding to STEP 12 in FIG. 3).

In this example, the second period T2 expires at time t14 (corresponding to YES in STEP12 of FIG. 3). Therefore, the reference capacitance Cr is updated with the detected capacitance C acquired at time t14 (corresponding to STEP4 in FIG. 3). That is, the detected capacitance C acquired at time t14 becomes the reference capacitance Cr for the detected capacitance C acquired at time t15 after the time corresponding to the predetermined period T has elapsed.

The black triangles illustrated in FIG. 4 represent the detected capacitance C that is acquired every predetermined period T when the touch state on the object 2 is maintained after time t4. A white triangle represents the reference capacitance Cr that is referenced when the detected capacitance C is obtained in the same case.

As described above, the first period T1 expires at time t6 (corresponding to YES in STEP7 of FIG. 3). Therefore, the identification flag is turned ON (corresponding to STEP8 in FIG. 3), and the reference capacitance Cr is updated by the detected capacitance C obtained at time t6 (corresponding to STEP4 in FIG. 3). Since the touch state with respect to the object 2 is maintained at time t6, the detected capacitance C obtained at time t6 has a large value. The detected capacitance C obtained at time t6 becomes a reference capacitance Cr with respect to the detected capacitance C obtained at time t7 after the time corresponding to the predetermined cycle T has elapsed. The reference capacitance Cr at time t7 also has a large value.

When the user's finger F or the like moves away from the object 2, the detected capacitance C rapidly decreases. In this example, this phenomenon occurs at time t8. Therefore, the difference between the detected capacitance C and the reference capacitance Cr acquired at time t8 exceeds the threshold value Cth (corresponding to YES in STEP9 of FIG. 3). Therefore, it is determined whether the identification flag is ON (corresponding to STEP 10 in FIG. 3).

In this example, the value of the identification flag turned ON at time t6 is maintained (corresponding to YES in STEP10 in FIG. 3). Therefore, it is determined that the rapid decrease in the detected capacitance C is due to the cancellation of the maintenance of the touch state. In this case, the updating of the reference capacitance Cr is stopped, and the acquisition of the detected capacitance C is repeated each time the time corresponding to the predetermined cycle T elapses (corresponding to STEP 13 in FIG. 3). Each time the detected capacitance C is acquired, it is determined whether or not the third period T3 has elapsed since the update of the reference capacitance Cr was stopped (corresponding to STEP 14 in FIG. 3).

In this example, the third period T3 expires at time t10 (corresponding to YES in STEP14 of FIG. 3). Therefore, the reference capacitance Cr is updated with the detected capacitance C obtained at time t10 (corresponding to STEP4 in FIG. 3). That is, the detected capacitance C acquired at time t10 becomes the reference capacitance Cr for the detected capacitance C acquired at time t11 after the time corresponding to the predetermined cycle T has elapsed. Also, the identification flag is reset and turned off.

As a result, the touch sensor 1 is brought into a state capable of detecting a touch operation again. In this example, it is determined that the touch operation has been performed at time t12, and updating of the reference capacitance Cr is stopped for the first period T1.

It is preferable that the length of the third period T3 is determined such that updating of the reference capacitance Cr is stopped before the subsequent touch operation is performed. For example, the length of the third period T3 can be set to be shorter than the time interval between a plurality of touch operations assumed when touch operations are repeated such as double tapping.

According to such a configuration, it is possible to suppress the occurrence of a situation in which a rapid decrease in the detection capacitance C is misidentified as being caused by environmental noise, and subsequent touch operations cannot be properly recognized.

Next, another example of processing performed by the control unit 131 will be described with reference to FIG. Steps that are substantially the same as the steps illustrated in FIG. 3 are given the same reference numerals, and repeated descriptions are omitted.

In this example, when it is determined that no touch operation has been performed for a predetermined period of time, control unit 131 executes calibration processing. The calibration process is performed with the acquisition of the detected capacitance C stopped. While the calibration process is being performed, updating of the reference capacitance Cr is also stopped. Determination that a touch operation has not been performed for a predetermined period of time can be performed by the processing illustrated in FIG. 6 .

The process illustrated in FIG. 6 is started after updating the reference capacitance Cr when the difference between the detected capacitance C and the reference capacitance Cr is equal to or less than a predetermined threshold value Cth (STEP 3 in FIG. 5). STEP4) following NO in STEP9 or NO in STEP9.

The control unit 131 increments the value n of the internal counter by one (STEP 31). Subsequently, the control unit 131 determines whether the value n of the internal counter has reached a predetermined value N (STEP 32). The value of N corresponds to the "predetermined period" divided by the period T. If the value n of the internal counter has not reached the predetermined value N (YES in STEP32), the process returns to STEP1, and after the time corresponding to the predetermined cycle T has elapsed, the next detected capacitance C is acquired. . If it is not determined that a touch operation has been performed, the above processing is repeated and the value n of the internal counter is incremented.

When the value n of the internal counter reaches a predetermined value N (NO in STEP 32), the control unit 131 saves the reference capacitance Cr at that point in the storage unit 132 (STEP 33), and starts the calibration process (STEP 34). ).

After the calibration process is finished, the controller 131 acquires the detected capacitance C. FIG. Furthermore, the control unit 131 determines whether the detected capacitance C is greater than the reference capacitance Cr and the difference between them exceeds a predetermined threshold value Cth (STEP 35). Specifically, the data input from the conversion circuit 122 and the data corresponding to the reference capacitance Cr stored in the storage unit 132 in STEP 23 are compared.

This process is performed to determine whether a touch operation has been performed on the object 2 during the calibration process. Since the calibration process is performed on the premise that no touch operation has been performed for a predetermined period of time, the detected capacitance C at the start of the calibration process takes a relatively small value. When the user's finger F or the like touches the object 2 during the calibration process, the detected capacitance C increases. Under such circumstances, the detected capacitance C obtained immediately after the calibration process is finished should be larger than the reference capacitance Cr before the calibration process is started, and the difference between the two should exceed the predetermined threshold value Cth. .

When it is determined that the detected capacitance C is greater than the reference capacitance Cr and that the difference between the two exceeds the predetermined threshold value Cth (YES in STEP35), the control unit 131 turns the identification flag ON. (STEP36). The role of the identification flag will be described later. The identification flag is a storage area capable of storing at least 1-bit information referenced by the control unit 131 . The storage area may be provided by memory or registers.

The control unit 131 updates the reference capacitance Cr with the detected capacitance C acquired at the end of the calibration process (STEP 37). After that, the process returns to STEP 1, and after a lapse of time corresponding to the predetermined cycle T, the next detected capacitance C is acquired. If it is determined that the detected capacitance C acquired at the end of the calibration process is greater than the reference capacitance Cr and the difference between the two does not exceed the predetermined threshold value Cth (NO in STEP 35), the control unit 131 updates the reference capacitance Cr with the detected capacitance C acquired at the end of the calibration process without changing the value of the identification flag (STEP 37). After that, the process returns to STEP1.

If the subsequently acquired detected capacitance C is equal to or less than the reference capacitance Cr and the difference between the two exceeds a predetermined threshold value Cth (NO in STEP2; YES in STEP9), the control unit 131 identifies It is determined whether the value of the flag is ON (STEP 20).

When it is determined that the value of the identification flag is not ON (NO in STEP 20), the control unit 131 stops updating the reference capacitance Cr and continues acquiring the detected capacitance C for each predetermined cycle T. (STEP 21).

Subsequently, the control unit 131 determines whether the second period T2 has passed since the update was stopped (STEP 22). The control unit 131 repeats acquisition of the detected capacitance for each predetermined cycle T without updating the reference capacitance Cr until it is determined that the second period T2 has elapsed (NO in STEP22).

When it is determined that the second period T2 has elapsed since the updating of the reference capacitance Cr was stopped (YES in STEP 22), the control unit 131 stores numerical data corresponding to the latest detected capacitance C in the storage unit 132. Numerical data corresponding to the reference capacitance Cr that has been set is updated (STEP 4). That is, the latest 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. At that time, the value of the identification flag is reset to the OFF state.

On the other hand, when it is determined that the value of the identification flag is ON (YES in STEP 20), the control unit 131 stops updating the reference capacitance Cr, and changes the detected capacitance C every predetermined cycle T. Acquisition is continued (STEP 23).

Subsequently, the control unit 131 determines whether or not the third period T3 has elapsed since the update was stopped (STEP 24). The third period T3 is shorter than the second period T2. The control unit 131 repeats acquisition of the detected capacitance for each predetermined period T without updating the reference capacitance Cr until it is determined that the third period T3 has passed (NO in STEP24).

When it is determined that the third period T3 has passed since the updating of the reference capacitance Cr was stopped (YES in STEP 24), the control unit 131 stores numerical data corresponding to the latest detected capacitance C in the storage unit 132. Numerical data corresponding to the reference capacitance Cr that has been set is updated (STEP 4). That is, the latest 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. At that time, the value of the identification flag is reset to the OFF state.

A phenomenon in which the detected capacitance falls below the reference capacitance is generally the effect of environmental noise. Therefore, when the detected capacitance C is smaller than the reference capacitance Cr and the difference between them is larger than the predetermined threshold value Cth, it is expected that environmental noise is acting on the touch sensor 1 . In this case, the control unit 131 does not determine that the touch operation has been performed on the object 2, and stops updating the reference capacitance Cr as the environmental noise countermeasure processing.

If the detected capacitance C that has decreased due to environmental noise is taken as the reference capacitance Cr, even if a detected capacitance C that is smaller than when a touch operation is performed is acquired, the difference from the reference capacitance Cr If is large, there is a possibility that the touch operation is erroneously recognized. According to the configuration as described above, it is possible to suppress the occurrence of such a situation.

On the other hand, the phenomenon that the amount of decrease in the detected capacitance C becomes larger than the predetermined threshold value Cth is caused by, in addition to the influence of the environmental noise, a state in which the user's finger F or the like is in contact with the object 2. , and the update of the reference capacitance Cr is restarted. In this case, the detected capacitance C obtained after resuming the update takes the value in the state where the touch operation is performed, and this value is used as the reference capacitance Cr. Therefore, based on the detected capacitance C that rapidly decreases when the user's finger F or the like moves away from the object 2, the environmental noise countermeasure processing is activated.

The control unit 131 refers to the identification flag that is turned ON when the detected capacitance C increases rapidly during the update process, thereby causing the amount of decrease in the detected capacitance C to become greater than the predetermined threshold value Cth. is due to environmental noise or touch operation during the calibration process. That is, when the detected capacitance C is smaller than the reference capacitance Cr and the difference between the two is larger than a predetermined threshold value Cth (first predetermined value), the control unit 131 controls the capacitance generated during the calibration process. is greater than a predetermined threshold value Cth (second predetermined value). The identification flag is turned ON when the amount of increase in capacitance that occurs during the calibration process is large. Therefore, when a phenomenon occurs in which the amount of decrease in the detected capacitance C becomes larger than the predetermined threshold value Cth while the identification flag is in the ON state, there is a high possibility that the phenomenon is caused by the touch operation during the calibration process. .

Therefore, when it is determined that the amount of increase in capacitance occurring during the calibration process is equal to or less than the second predetermined value, the control unit 131 updates the reference capacitance Cr for the second period T2 as a countermeasure against environmental noise. Stop. The length of the second period T2 may be determined based on the expected duration of environmental noise.

On the other hand, if it is determined that the amount of increase in capacitance that occurred during the calibration process is greater than the second predetermined value, the control unit 131 increases the reference capacitance Cr for a third period T3 shorter than the second period T2. Stop updating. The reason why the third period T3 is shorter than the second period T2 is to avoid continuation of the environmental noise countermeasure processing under circumstances not caused by environmental noise, and to quickly return to a normal state in which touch operations can be detected. be.

According to the configuration as described above, it is possible to accurately determine a touch operation even in a noisy environment.

An operation example of the touch sensor 1 configured as shown in FIGS. 5 and 6 will be described with reference to FIG. In FIG. 7, 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.

In this example, at time t1, it is determined that no touch operation has been performed for a predetermined period. Therefore, the reference capacitance Cr referred to at time t1 is stored in the storage unit 132 (corresponding to STEP33 in FIG. 6).

After that, the calibration process is executed over the period T0 (corresponding to STEP34 in FIG. 6). During this time, neither the acquisition of the detected capacitance C nor the update of the reference capacitance Cr is stopped.

When the calibration process ends at time t2, the detected capacitance C at that time is obtained and compared with the reference capacitance Cr stored at time t1 before the start of the calibration process (corresponding to STEP35 in FIG. 6).

In this example, the detected capacitance C acquired at time t2 is smaller than the reference capacitance Cr stored at time t1 (corresponding to NO in STEP35 of FIG. 6). Therefore, the reference capacitance Cr is updated by the detected capacitance C obtained at time t2 without turning the identification flag ON (corresponding to STEP37 in FIG. 6). That is, the detected capacitance C obtained at time t2 becomes the reference capacitance Cr for the detected capacitance C obtained at time t3 after the time corresponding to the predetermined cycle T has elapsed.

The detected capacitance C obtained at time t3 is smaller than the reference capacitance Cr at that time (corresponding to NO in STEP2 of FIG. 5). Therefore, it is determined whether or not the amount of decrease in the detected capacitance C from the reference capacitance Cr exceeds the threshold value Cth (corresponding to STEP9 in FIG. 5).

In this example, the difference between the detected capacitance C and the reference capacitance Cr obtained at time t3 exceeds the threshold Cth (corresponding to YES in STEP9 of FIG. 5). Therefore, it is determined whether the identification flag is ON (corresponding to STEP 20 in FIG. 5).

In this example, the identification flag is not turned ON at time t2 (corresponding to NO in STEP 20 in FIG. 5). Therefore, the rapid drop in the detected capacitance C is determined to be the effect of environmental noise. In this case, the updating of the reference capacitance Cr is stopped, and the acquisition of the detected capacitance C is repeated each time the time corresponding to the predetermined cycle T elapses (corresponding to STEP 21 in FIG. 5). Each time the detected capacitance C is acquired, it is determined whether the second period T2 has elapsed since the update of the reference capacitance Cr was stopped (corresponding to STEP 22 in FIG. 5).

In this example, the second period T2 expires at time t9 (corresponding to YES in STEP22 of FIG. 5). Therefore, the reference capacitance Cr is updated with the detected capacitance C acquired at time t9 (corresponding to STEP4 in FIG. 5). That is, the detected capacitance C obtained at time t9 becomes the reference capacitance Cr for the detected capacitance C obtained at time t10 after the time corresponding to the predetermined cycle T has elapsed.

The black triangles illustrated in FIG. 7 represent the detected capacitance C obtained at each predetermined period T when a touch operation is performed during the calibration process. A white triangle represents the reference capacitance Cr that is referenced when the detected capacitance C is obtained in the same case.

As described above, the calibration process ends at time t2. Therefore, the detected capacitance C at that time is acquired and compared with the reference capacitance Cr stored at time t1 before the start of the calibration process (corresponding to STEP 35 in FIG. 6).

In this example, the detected capacitance C acquired at time t2 is greater than the reference capacitance Cr stored at time t1, and the difference between the two exceeds a predetermined threshold value Cth (see FIG. 6). corresponding to YES in STEP 35). Therefore, the identification flag is turned ON (corresponding to STEP36 in FIG. 6), and the reference capacitance Cr is updated by the detected capacitance C acquired at time t2 (corresponding to STEP37 in FIG. 6). Since the touch operation is performed during the calibration process, the detected capacitance C obtained at time t2 has a large value. The detected capacitance C obtained at time t2 becomes the reference capacitance Cr for the detected capacitance C obtained at time t3 after the time corresponding to the predetermined cycle T has elapsed. The reference capacitance Cr at time t3 also has a large value.

When the user's finger F or the like moves away from the object 2, the detected capacitance C rapidly decreases. In this example, this phenomenon occurs at time t3. Therefore, the difference between the detected capacitance C and the reference capacitance Cr acquired at time t3 exceeds the threshold Cth (corresponding to YES in STEP9 of FIG. 5). Therefore, it is determined whether the identification flag is ON (corresponding to STEP 20 in FIG. 5).

In this example, the value of the identification flag turned ON at time t2 is maintained (corresponding to YES in STEP20 in FIG. 5). Therefore, it is determined that the rapid decrease in the detected capacitance C is due to the cancellation of the maintenance of the touch state. In this case, the updating of the reference capacitance Cr is stopped, and the acquisition of the detected capacitance C is repeated every time the time corresponding to the predetermined cycle T elapses (corresponding to STEP 23 in FIG. 5). Each time the detected capacitance C is acquired, it is determined whether or not the third period T3 has elapsed since the update of the reference capacitance Cr was stopped (corresponding to STEP 24 in FIG. 5).

In this example, the third period T3 expires at time t5 (corresponding to YES in STEP24 of FIG. 5). Therefore, the reference capacitance Cr is updated by the detected capacitance C obtained at time t5 (corresponding to STEP4 in FIG. 5). 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. Also, the identification flag is reset and turned off.

As a result, the touch sensor 1 is brought into a state capable of detecting a touch operation again. In this example, it is determined that the touch operation has been performed at time t7, and updating of the reference capacitance Cr is stopped.

It is preferable that the length of the third period T3 is determined such that updating of the reference capacitance Cr is stopped before the subsequent touch operation is performed. For example, the length of the third period T3 can be set to be shorter than the time interval between a plurality of touch operations assumed when touch operations are repeated such as double tapping.

According to such a configuration, it is possible to suppress the occurrence of a situation in which a rapid decrease in the detection capacitance C is misidentified as being caused by environmental noise, and subsequent touch operations cannot be properly recognized.

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.

The touch sensor 1 can also 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 touch operations 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, T1: first period, T2: second period, T3: third period

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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period,
When it is determined that the update of the reference capacitance for the first period has been stopped, updating the reference capacitance is stopped for a third period shorter than the second period,
touch sensor. The length of the third period is defined to be shorter than the time interval between multiple operations assumed when the operation is repeated,
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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
when the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period,
When it is determined that the update of the reference capacitance for the first period has been stopped, updating the reference capacitance is stopped for a third period shorter than the second period,
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 for a first period when the detected capacitance is greater than the reference capacitance and the difference is greater than a predetermined value;
If the detected capacitance is smaller than the reference capacitance and the difference is greater than a predetermined value, determining whether updating of the reference capacitance in the first period has been stopped;
If it is determined that the update of the reference capacitance for the first period has not been stopped, stopping the update of the reference capacitance for only a second period;
When it is determined that the update of the reference capacitance for the first period has been stopped, the update of the reference capacitance is stopped for a third period shorter than the second period,
computer program.

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