JP5146657B2 - Touch switch detection device and water supply device using the same - Google Patents

Description

  An aspect of the present invention generally relates to a touch switch detection device and a water supply device using the touch switch detection device, and more specifically, to a capacitive touch switch detection device and a water supply device using the same.

  Based on the output frequency changed according to the difference between the electrostatic capacity of the human body in contact with the electrode and the electrostatic capacity of the water droplets, it is determined whether the human body has operated or whether the water droplets have adhered. There is something to judge (see, for example, Patent Document 1). Also, based on the change in the output of the capacitance sensor caused by the difference in the total amount of charge detected by the non-contact type capacitance sensor, it is judged whether a person has operated or a water droplet has adhered. (See, for example, Patent Document 2).

Here, when the capacitive touch switch detection device is used as an operation switch for a water supply device such as a water supply device, it is necessary to assume that water is directly applied to the touch detection electrode. However, in the apparatus described in Patent Document 1 (Japanese Patent Laid-Open No. 2002-57564), it is determined whether a person has operated or a water droplet has adhered based only on the difference in capacitance. It is difficult to make a judgment when operating with wet fingers. Further, in the apparatus described in Patent Document 2 (Japanese Patent Laid-Open No. 2004-212344), it is determined whether or not the object is a human body only from the output change of the capacitance sensor when the object approaches. It is difficult to determine the operation when the human body is approached slowly and the case where water droplets are attached.
JP 2002-57564 A JP 2004-212344 A

  Aspects of the present invention provide a touch switch detection device that can accurately determine whether a touch switch is detected by a human operation or water droplet adhesion, and a water supply device using the touch switch detection device.

  According to one aspect of the present invention, a touch detection electrode that detects a change in capacitance due to approach or contact of an object, a detection unit that outputs a detection output reflecting the change in capacitance, and the detection output An operation determination unit that determines presence or absence of a user's operation based on the operation determination unit, wherein the operation determination unit determines whether the detection output change rate at the start of detection is equal to or less than an object determination value. An object determination unit that temporarily determines an object, and a contact determination unit that determines contact of the user based on whether or not the detection output is equal to or greater than a detection threshold, and the operation determination unit includes the object A touch switch detection device, wherein a determination unit sets the detection threshold according to a result of provisional determination, and determines whether or not there is an operation by the user based on whether the detection output is equal to or higher than the detection threshold. Is provided.

  According to another aspect of the present invention, the touch switch detection device, an electromagnetic valve that opens and closes a water supply channel, a water outlet that discharges water supplied through the water supply channel, A water supply apparatus comprising: a control unit that controls the operation of the electromagnetic valve based on the determination of the operation determination unit.

  ADVANTAGE OF THE INVENTION According to the aspect of this invention, the touch switch detection apparatus and water supply apparatus using the touch switch detection apparatus which can judge exactly whether detection of a touch switch is by human operation, or adhesion of a water drop etc. are provided. .

The first invention is based on a touch detection electrode that detects a change in capacitance due to the approach or contact of an object, a detection unit that outputs a detection output reflecting the change in capacitance, and the detection output. An operation determination unit that determines whether or not a user has performed an operation. The operation determination unit temporarily determines the object based on whether or not a change rate of the detection output at the start of detection is equal to or less than an object determination value. An object determination unit for determining, and a contact determination unit for determining the contact of the user based on whether the detection output is equal to or greater than a detection threshold, and the operation determination unit includes: When the object is temporarily determined to be the user, the detection output when the object is temporarily determined to be the user is set as the detection threshold, and the object determination unit detects the object as a water drop. If it is temporarily determined that it is, the user is temporarily determined to be the user Wherein a value greater than the detection output and the detection threshold Kino, the detection output touch switch detection device, wherein a determination whether the operation of the user on whether it is above the detection threshold It is.
According to this touch switch detection device, when the object approaches the touch detection electrode, the change rate of the detection output varies depending on the difference in capacitance and the approach speed, so that the object is a human finger. It is possible to determine whether it is a water drop or not, and it is possible to set an optimum detection threshold corresponding to each. As a result, it is possible to accurately determine whether the operation of the touch switch detection device is due to a human operation or due to water droplet adhesion.
In addition, according to this touch switch detection device, when a user tries to operate with a wet finger, water adheres first, and the phenomenon that the detection output increases when a person's finger touches afterwards is accurately detected. Can be caught. This is because the finger is in contact with the spread water droplet, so that the apparent finger contact area increases, and the detection output at that time increases. This touch switch detection device can accurately capture this phenomenon. Therefore, it is possible to more accurately determine when the touch detection electrode is pressed with a wet finger, when the touch detection electrode with water droplets is pressed with a dry finger, and when water droplets are attached to the touch detection electrodes. it can.

According to a second invention, in the first invention, when the detection output is equal to or greater than the detection threshold value, the operation determination unit determines that the user's operation has been performed. It is a detection device.
According to this touch switch detection device, since the user has a large capacitance with respect to the water droplet and the detection output becomes high, it is possible to more accurately determine whether or not the operation of the touch switch detection device is a human operation. Can do.

Moreover, 3rd invention is the touch switch detection apparatus of 1st or 2nd invention, the electromagnetic valve which opens and closes a water supply flow path, The water outlet which discharges the water supplied via the said water supply flow path, A water supply apparatus comprising: a control unit that controls the operation of the electromagnetic valve based on the determination of the operation determination unit.
According to this water supply apparatus, even if water drops are applied, it is possible to perform a water discharge operation by making a more accurate operation determination without malfunctioning.

According to a fourth aspect , in the third aspect , at least one of the value of the object determination value and the value of the detection threshold value is changed according to the open / close state of the electromagnetic valve. It is a water supply device.
According to this water supply device, the judgment criteria of the touch switch detection device can be changed according to each of the state before the start of water discharge and the state in which water is easily applied during water discharge, and more accurate operation considering the influence of water Judgment can be made.

According to a fifth aspect of the present invention, in the fourth aspect , when the electromagnetic valve is in an open state, the operation determination unit has the object determination value having a larger value than that in the case where the electromagnetic valve is in a closed state. The water supply apparatus is characterized in that the detection threshold value is set.
According to this water supply device, when the electromagnetic valve is in an open state, the touch detection electrode is likely to be splashed with water, and is often operated with a wet hand when stopping the water. More accurate operation judgment can be made in consideration of the influence of water droplets on

Embodiments of the present invention will be described below with reference to the drawings. In addition, in each drawing, the same code | symbol is attached | subjected to the same component and detailed description is abbreviate | omitted suitably.
FIG. 1 is a block diagram of a touch switch detection device according to an embodiment of the present invention.
A touch switch detection device 100 according to an embodiment of the present invention includes a touch detection electrode 200, a detection unit 300, and an operation determination unit 400. As will be described later, the touch detection electrode 200 is provided, for example, directly below a panel of a water supply device or the like. Note that touching the panel by the user is equivalent to touching the touch detection electrode 200. The detection unit 300 includes an oscillation unit 310 and a voltage conversion unit 320. Further, the operation determination unit 400 includes a contact determination unit 410 and an object determination unit 430.

  The oscillation unit 310 outputs a high frequency signal, forms a high frequency voltage based on the high frequency signal, and applies the high frequency voltage to the touch detection electrode 200. When the user does not touch the touch detection electrode 200 with a finger, the voltage amplitude of the high frequency voltage applied to the touch detection electrode 200 is not changed and is output to the voltage conversion unit 320. On the other hand, when the user touches the touch detection electrode 200 with a finger, the capacitance between the touch detection electrode 200 and the ground changes. As a result, the voltage amplitude of the high-frequency voltage applied to the touch detection electrode 200 changes according to the change in capacitance and is output to the voltage conversion unit 320. The voltage conversion unit 320 outputs the output of the oscillation unit 310 to the operation determination unit 400 as a voltage value detection signal.

  When the contact determination unit 410 receives the detection signal (detection output) output from the voltage conversion unit 320, the contact determination unit 410 determines whether or not there is a human operation based on an operation described in detail later. On the other hand, the object determination unit 430 temporarily determines the object that has touched the touch detection electrode 200 according to the output change rate at the start of detection of the detection output output from the voltage conversion unit 320.

FIG. 2 is a block diagram of a water supply device using the touch switch detection device according to the present embodiment.
Moreover, FIG. 3 represents the schematic diagram of the water supply apparatus using the touch switch detection apparatus concerning this embodiment.
The touch switch detection device 100 according to the present embodiment is used in, for example, a water supply device. A water supply device 500 shown in FIGS. 2 and 3 includes a touch switch detection device 100, a control unit 510, an electromagnetic valve 520, and a water discharge port 530.

  The water supply device illustrated in FIG. 3 includes touch switch detection devices 100a, 100b, and 100c. For example, the touch switch detection device 100a is a “water discharge switch”, the touch switch detection device 100b is a “flow rate adjustment switch”, and a touch switch. The detection device 100c can have a function as a “water stop switch”.

  Based on the signal output from touch switch detection device 100, control unit 510 determines the presence or absence of a user's operation, and instructs electromagnetic valve 520 to perform a spouting operation. The electromagnetic valve 520 opens and closes the valve based on the instruction output from the control unit 510. Thereby, the water discharge from the water outlet 530 of the water supply apparatus 500 is controlled.

FIG. 4 is a graph showing a voltage value (actual measurement value) output from the detection unit when the touch detection electrode is pressed with a dry finger.
The vertical axis of the graph shown in FIG. 4 represents a voltage value (100 mV / div), and the horizontal axis represents time (50 ms / div).

  When the user touches the touch detection electrode 200 with a dry finger, as described above with reference to FIG. 1, the capacitance between the touch detection electrode 200 and the ground changes, and the voltage value output from the detection unit 300 increases. The detection signal changes. In addition, when the touch detection electrode 200 is touched with a dry finger, the contact area of the finger with the touch detection electrode 200 gradually increases with the deformation of the fingertip, so that the graph shown in FIG. The voltage value (detection output) output from the detection unit 300 gradually increases. Here, the conversion method of the voltage conversion unit 320 may be such that the voltage value decreases when the user touches the touch detection electrode 200 with a finger.

  When the user touches the touch detection electrode 200 with his / her finger, the capacitance between the touch detection electrode 200 and the ground remains changed (increased) as compared with the case where the user does not touch the touch detection electrode 200. As shown in the graph of FIG. 4, the voltage value output from the detection unit 300 remains substantially constant while being increased. The time t1 from when the voltage value starts to rise until it becomes substantially constant is, for example, about 20 milliseconds.

  Thereafter, even when the user removes the dry finger from the touch detection electrode 200, the contact area of the finger with respect to the touch detection electrode 200 gradually decreases as the fingertip is deformed. The value gradually decreases. When the dry finger is completely separated from the touch detection electrode 200, the voltage value output from the detection unit 300 decreases to the voltage value before touching with the dry finger as shown in the graph of FIG. It becomes.

FIG. 5 is a graph showing a voltage value (actual measurement value) output from the detection unit when the touch detection electrode of this embodiment is pressed with a wet finger.
The vertical axis and the horizontal axis of the graph shown in FIG. 5 represent the voltage value (100 mV / div) and time (50 ms / div), respectively, similarly to the graph shown in FIG. Note that the graph shown in FIG. 5 is a waveform of a voltage value when the user presses the touch detection electrode while the water drop on the finger does not fall on the touch detection electrode 200 and remains on the finger. Represents.

  When the user touches the touch detection electrode 200 with a wet finger, the water attached to the finger spreads quickly to the touch detection electrode 200, so that the voltage value increases at a higher rate than when touched with a dry finger. . The time t2 from when the voltage value starts to rise until it becomes substantially constant is, for example, about 10 milliseconds. Furthermore, since the finger is wet with water, the apparent contact area with respect to the touch detection electrode 200 is increased by the amount wet. Therefore, the capacitance is larger than when touched with a dry finger, and as a result, the voltage value while the user touches the touch detection electrode 200 with a wet finger is dry as shown in FIG. It is larger than the voltage value while touching with a finger (see FIG. 4).

  After that, when the user releases the wet finger from the touch detection electrode 200, the touch detection electrode 200 and the finger come into contact with each other through the water due to the surface tension of water even if the finger tries to move away from the touch detection electrode 200. The state continues. When the finger is separated to some extent, the water is separated from the finger, and as a result, the finger is separated from the touch detection electrode 200 at a stretch. Therefore, the contact area between the finger and the touch detection electrode 200 does not gradually decrease as in the case where the touch detection electrode 200 is pressed with a dry finger. Therefore, when the wet finger moves away from the touch detection electrode 200, the voltage value decreases at a larger change rate than that of the dry finger.

FIG. 6 is a graph illustrating a voltage value (actual measurement value) output from the detection unit when a water droplet is attached to the touch detection electrode.
Note that the vertical axis and the horizontal axis of the graph shown in FIG. 6 represent the voltage value (100 mV / div) and time (50 ms / div), respectively, as in the graph shown in FIG.

  When a water droplet is attached to the touch detection electrode 200, the capacitance between the touch detection electrode 200 and the water droplet changes, and the detection signal of the voltage value output from the detection unit 300 changes, as in the case of touching with a finger. To do. When a water droplet is attached to the touch detection electrode 200, the contact area of the water droplet with respect to the touch detection electrode 200 is rapidly increased as compared with the case of touching with a dry finger or a wet finger. Therefore, as shown in the graph of FIG. 6, the change rate (increase rate) of the voltage value output from the detection unit 300 is larger than the increase rate when touched with a dry finger or a wet finger. The time t3 from the start of the increase of the voltage value to the end of the increase is, for example, about 5 milliseconds.

  Here, when the user is touching the touch detection electrode 200, since the person is also in contact with the ground, the charge sent from the touch detection electrode 200 to the user escapes to the ground through the human body. Therefore, the voltage value output from the detection unit 300 until the user lifts the finger is maintained at a certain voltage value. On the other hand, when a water droplet is attached, the charge is sent from the touch detection electrode 200 to the water droplet, so that charging proceeds to the capacitive component of the water droplet, and finally the touch electrode 200 and the water droplet are at the same potential. End up. Therefore, even if the water droplet remains on the touch detection electrode 200, the voltage value gradually decreases as shown in FIG. The speed at which the charge is transferred from the touch detection electrode 200 to the water droplet is determined by the capacitance component of the water droplet, but is slower than the speed at which the user lifts the finger from the touch detection electrode 200. Therefore, when a water droplet is attached to the touch detection electrode 200, the voltage value gradually decreases after increasing to approximately the same voltage value as when touching with a dry finger.

  As described above, even when the user presses the touch detection electrode 200 with his / her finger, the rate of increase at the start of detection of the voltage value output from the detection unit 300 differs depending on the wetness of the finger. . Therefore, even if the voltage value changes at a higher rate than when the touch detection electrode 200 is pressed with a dry finger, it cannot be determined that the object that has touched the touch detection electrode 200 is a water droplet. That is, based on the rate of change (increase rate) at the start of detection of the voltage value output from the detection unit 300, the presence or absence of the user's operation is determined only by determining the object that has touched the touch detection electrode 200. It is not possible.

Next, a specific example of the determination operation of the touch switch detection device according to the present embodiment will be described with reference to the drawings.
FIG. 7 is a schematic view illustrating the case where the touch detection electrode is pressed with a dry finger. 7A is a schematic diagram illustrating a state in which the touch detection electrode is touched with a dry finger, and FIG. 7B is a schematic diagram illustrating a voltage value output from the detection unit.

  When the user presses the touch detection electrode 200 with a dry finger, the voltage value output from the detection unit 300 gradually increases (range A1), and the voltage value remains increased and becomes substantially constant (range B1). Here, the operation determination unit 400 calculates the rate of change (increase rate) of the voltage value output from the detection unit 300, as will be described in detail later. In accordance with the rate of change (here, about 20 milliseconds), the object that has touched the touch detection electrode 200 is provisionally determined, and a predetermined detection threshold that is a determination criterion for the presence or absence of the user's operation is set.

  According to the increase rate of the voltage value shown in FIG. 7B, since the object that has touched the touch detection electrode 200 is likely to be a finger, the object is provisionally determined to be a finger. This is because, as described above with reference to FIG. 4, when the contacted object is a finger, the contact area with respect to the touch detection electrode 200 gradually increases as the fingertip is deformed. Based on the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “V1”.

  Here, as illustrated in FIG. 7B, when the voltage value output from the detection unit 300 is equal to or greater than the predetermined detection threshold V1, the operation determination unit 400 determines that there has been a user's operation. The touch switch detection apparatus 100 accepts this operation. That is, the touch switch detection device 100 according to the present embodiment does not determine the presence or absence of the user's operation only by determining the target object that has touched the touch detection electrode 200, but does not determine the predetermined operation set according to the target object. The presence or absence of the user's operation is determined by comparing the magnitude relationship between the detection threshold and the voltage value output from the detection unit 300.

  On the other hand, when the voltage value output from the detection unit 300 is not equal to or greater than the predetermined detection threshold V1, the operation determination unit 400 determines that there is no user operation, as will be described later, and the touch switch The detection apparatus 100 does not accept this operation.

  FIG. 8 is a schematic view illustrating a case where a touch detection electrode with a water droplet is pressed with a dry finger. 8A is a schematic diagram illustrating a state in which the touch detection electrode 200 with water droplets is pressed with a dry finger, and FIG. 8B is a schematic diagram illustrating a voltage value output from the detection unit. It is.

  When the user presses the touch detection electrode 200 with water droplets with a dry finger, the apparent contact area with respect to the touch detection electrode 200 immediately expands, so the touch detection electrode 200 without water droplets is pressed with a dry finger. The voltage value increases at a rate of increase greater than (range A2). In addition, when the user is pressing the touch detection electrode 200, the apparent contact area with the touch detection electrode 200 is increased by the amount of wetness, so that the voltage remains substantially constant (range B2). .

  Here, the operation determination unit 400 calculates the rate of increase of the voltage value output from the detection unit 300 as in the case illustrated in FIG. 7. In accordance with the rate of change (here, about 5 milliseconds), the object that touches the touch detection electrode 200 is provisionally determined, and a predetermined detection threshold value that is a determination criterion for the presence or absence of the user's operation is set.

  According to the increase rate of the voltage value shown in FIG. 8B, the increase rate is larger than the increase rate when the touch detection electrode 200 is pressed with a dry finger. Is highly likely to be a water droplet, and the object is provisionally determined to be a water droplet. Based on the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “V2” that is larger than “V1”. Here, even when the predetermined detection threshold is set to “V2” larger than “V1”, as shown in FIG. 8B, when the voltage value is equal to or higher than the predetermined detection threshold V2. The operation determination unit 400 determines that there has been a user's operation, and the touch switch detection device 100 accepts this operation.

  As described above, when the touch detection electrode 200 with water droplets is pressed with a dry finger, the apparent contact area with the touch detection electrode 200 is increased by the wet amount. The magnitude relationship between the predetermined detection threshold V2 and the voltage value as shown can occur. Therefore, even when it is temporarily determined that the object that has touched the touch detection electrode 200 is a water droplet according to the rate of increase at the start of voltage value detection, the magnitude relationship between the subsequent voltage value and the predetermined detection threshold value Depending on the situation, the operation determination unit 400 may determine that there has been a user operation, and the touch switch detection device 100 may accept this operation.

FIG. 9 is a schematic view illustrating the case where the touch detection electrode is pressed with a wet finger. 9A is a schematic diagram illustrating a state in which the touch detection electrode is touched with a wet finger, and FIG. 9B is a schematic diagram illustrating a voltage value output from the detection unit.
In this specific example, a case where a water droplet attached to a finger does not fall on the touch detection electrode will be described as an example.

  When the touch detection electrode 200 is pressed while the water droplet is still on the finger, the water attached to the finger spreads quickly against the touch detection electrode 200, so that the voltage value is increased at a higher rate than when touched with a dry finger. Rises (range A3). Further, in the state where the user is pressing the touch detection electrode 200, the apparent contact area with the touch detection electrode 200 is increased by the wet amount as in the specific example shown in FIG. And remains substantially constant (range B3).

  Here, the operation determination unit 400 calculates an increase rate of the voltage value output from the detection unit 300. In accordance with the rate of change (here, about 10 milliseconds), the object that touches the touch detection electrode 200 is provisionally determined, and a predetermined detection threshold that is a determination criterion for the presence or absence of the user's operation is set.

  According to the rate of increase of the voltage value shown in FIG. 9B, the rate of increase is larger than the rate of increase when the touch detection electrode 200 is pressed with a dry finger. to decide. Based on the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “V2” that is larger than “V1”. Here, even when the predetermined detection threshold is set to “V2” larger than “V1”, as shown in FIG. 9B, when the voltage value is equal to or higher than the predetermined detection threshold V2. The operation determination unit 400 determines that there has been a user's operation, and the touch switch detection device 100 accepts this operation.

  Even when the touch detection electrode 200 is pressed while the water droplet remains on the finger, the apparent contact area with respect to the touch detection electrode 200 is equivalent to the wetness as in the specific example shown in FIG. Therefore, the magnitude relationship between the predetermined detection threshold value V2 and the voltage value as shown in FIG. 9B may occur. In the case where the water droplets attached to the finger fall on the touch detection electrode 200 and then the touch detection electrode 200 is pressed with the finger, it can be considered in the same manner as the specific example shown in FIG.

  FIG. 10 is a schematic view illustrating the case where water droplets are attached to the touch detection electrode. 10A is a schematic diagram illustrating a state in which water droplets are attached to the touch detection electrode, and FIG. 10B is a schematic diagram illustrating a voltage value output from the detection unit.

  When the water droplet is attached to the touch detection electrode 200, as described above with reference to FIG. 6, the voltage value output from the detection unit 300 increases at a large increase rate (range A4). Thereafter, as described above with reference to FIG. 6, the increased voltage value gradually decreases even when the water droplet remains with the touch detection electrode 200 (range B <b> 4).

  Here, the operation determination unit 400 calculates an increase rate of the voltage value output from the detection unit 300. In accordance with the rate of change (here, about 5 milliseconds), the object that touches the touch detection electrode 200 is provisionally determined, and a predetermined detection threshold value that is a determination criterion for the presence or absence of the user's operation is set.

  According to the increase rate of the voltage value shown in FIG. 10B, the increase rate is larger than the increase rate when the touch detection electrode 200 is pressed with a dry finger. Is highly likely to be a water droplet, and the object is provisionally determined to be a water droplet. Based on the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “V2” that is larger than “V1”. Here, if the water droplet remains on the touch detection electrode 200, the voltage value becomes equal to or higher than the predetermined detection threshold V2 by setting the predetermined detection threshold to “V2” larger than “V1”. Absent. This is because the voltage value never exceeds the predetermined detection threshold V2 because the size of the capacitive component of the water droplet is smaller than the capacitive component of the human body.

  Therefore, when it is temporarily determined that the object that has touched the touch detection electrode 200 is a water droplet according to the rate of increase at the start of voltage value detection, the subsequent voltage value does not become equal to or greater than the predetermined detection threshold V2. The operation determination unit 400 determines that there is no user operation, and the touch switch detection device 100 does not accept this operation.

FIG. 11 is a flowchart illustrating a specific example of the operation of the operation determination unit of this embodiment.
The operation determination unit 400 first determines an object that has touched the touch detection electrode 200 by the operation of the object determination unit 430 (step S102). The operation of the object determination unit 430 will be described later with reference to FIG.

When the object determination unit 430 determines that the object that has touched the touch detection electrode 200 is “object 1” (step S104: YES), the operation determination unit 400 determines whether or not the user has performed an operation. The predetermined detection threshold value which is a reference is set to “V1” (step S110). Similarly, in the case of “object 2” (step S106: YES), the operation determination unit 400 sets “V2” as the predetermined detection threshold (step S112), and “object (N−1)”. ”(Step S108: YES),“ V _n−1 ”is set as the predetermined detection threshold value (step S114). In other cases (step S108: NO),“ V _n ”is set as the predetermined detection threshold value. Set (step S116).

  Subsequently, it is determined by the operation of the contact determination unit 410 whether or not there has been a user operation (step S118). The operation of the contact determination unit 410 will be described later with reference to FIG. If it is determined by the contact determination unit 410 that there has been a user operation, the operation determination unit 400 recognizes this determination and ends the operation (step S120). On the other hand, when the contact determination unit 410 determines that there is no user operation, the operation determination unit 400 recognizes this determination and ends the operation (step S120).

FIG. 12 is a flowchart illustrating a specific example of the operation of the object determination unit of the present embodiment.
The object determination unit 430 first reads the detection output (voltage value) output from the detection unit 300 (step S202). Subsequently, the change rate (increase rate) of the voltage value is calculated based on the read voltage value (step S204). If the rate of change is “0” (step S206: NO), the detection output (voltage value) output from the detection unit 300 is read again (step S202). On the other hand, if the rate of change is not “0” (step S206: YES), the object determining unit 430 determines whether the absolute value of the rate of change calculated in step S204 is equal to or smaller than the absolute value of the predetermined object determined value A1. It is determined whether or not (step S208).

  In step S208, the magnitude relationship between the absolute values of the change rate of the detection output (voltage value) and the object determination value A1 is compared. The specific examples shown in FIGS. As described above, if the change rate of the voltage value when the object touches the touch detection electrode 200 is positive (plus), the absolute value need not be considered. On the other hand, depending on the configuration of the detection circuit of the detection unit 300, the change rate of the voltage value when the object touches the touch detection electrode 200 may be negative (minus). As described above, since the change rate of the voltage value when the target object touches the touch detection electrode 200 may be positive or negative, the operation of the specific example will be described below in consideration of the absolute value. . A large change rate of the detection output (voltage value) means that the gradient of the change is steep. On the other hand, a small change rate of the detection output (voltage value) means that the gradient of the change is gentle.

  If the absolute value of the change rate calculated in step S204 is less than or equal to the absolute value of the predetermined object determination value A1, the object determination unit 430 determines that the object that has touched the touch detection electrode 200 is “object 1”. A provisional determination is made (step S214). Examples of the “object 1” include a dry finger. On the other hand, if the absolute value of the change rate calculated in step S204 is not less than or equal to the absolute value of the predetermined object determination value A1 (step S208: NO), the object determination unit 430 calculates the absolute value of the change rate calculated in step S204. It is determined whether or not the value is equal to or less than an absolute value of a predetermined object determination value A2 (step S210).

If the absolute value of the change rate calculated in step S204 is less than or equal to the absolute value of the predetermined object determination value A2, the object determination unit 430 determines that the object that has touched the touch detection electrode 200 is “object 2”. A provisional determination is made (step S216). Examples of the “object 2” include water droplets and wet fingers. On the other hand, if the absolute value of the change rate calculated in step S204 is not less than or equal to the absolute value of the predetermined object determination value A2 (step S210: NO), the object determination unit 430 calculates the absolute value of the change rate calculated in step S204. It is determined whether or not the value is equal to or less than an absolute value of a predetermined object determination value _An-1 (step S212).

If the absolute value of the change rate calculated in step S204 is equal to or less than the absolute value of the predetermined object determination value _An-1 , the object determination unit 430 determines the object that has touched the touch detection electrode 200 as “object (N -1) "(step S218). On the other hand, if the absolute value of the change rate calculated in step S204 is not less than or equal to the absolute value of the predetermined object determination value _An-1 (step S212: NO), the object determination unit 430 contacts the touch detection electrode 200. The determined object is provisionally determined to be “object N” (step S220).

By performing such an operation, the object determination unit 430 temporarily determines the object that has touched the touch detection electrode 200. Then, as described above with reference to FIG. 11, the operation determination unit 400 sets a predetermined detection threshold that is a determination criterion for the presence / absence of the user's operation, according to the object temporarily determined by the object determination unit 430. Note that the relationship of the following expressions holds for the object determination value and the predetermined detection threshold.

| A1 | <| A2 | <... <| A _n-1 | <| A _n | Formula (1)

| V1 | <| V2 | <... <| V _n-1 | <| V _n | Equation (2)

FIG. 13 is a flowchart illustrating a specific example of the operation of the contact determination unit of the present embodiment.
The contact determination unit 410 first reads the detection output (voltage value) output from the detection unit 300 (step S302). Subsequently, it is determined whether or not the absolute value of the read voltage value is equal to or larger than the absolute value of the predetermined detection threshold (step S304). Here, the predetermined detection threshold is the predetermined detection threshold set in step S110, step S112, step S114, or step S116 shown in FIG.

  If the absolute value of the voltage value is greater than or equal to the absolute value of the predetermined detection threshold (step S304: YES), the contact determination unit 410 determines that there has been a user operation. On the other hand, when the absolute value of the voltage value is not equal to or larger than the absolute value of the predetermined detection threshold (step S304: NO), the contact determination unit 410 determines that there is no user operation.

  By performing such an operation, the contact determination unit 410 determines whether or not there has been a user operation. Then, as described above with reference to FIG. 11, when the contact determination unit 410 determines that there is a user operation, the operation determination unit 400 recognizes this determination and ends the operation. On the other hand, when the contact determination unit 410 determines that there is no user operation, the operation determination unit 400 recognizes this determination and ends the operation.

Next, the operation of the operation determination unit according to the present specific example will be further described with reference to time charts corresponding to the operations in the flowcharts illustrated in FIGS.
FIG. 14 is a time chart for explaining a specific example of the operation of the operation determination unit of this specific example. FIG. 14A is a schematic diagram illustrating the voltage value when the touch detection electrode is pressed with a dry finger, and FIG. 14B is the case where the touch detection electrode is pressed with a wet finger. FIG. 14C is a schematic diagram illustrating the voltage value, and FIG. 14C is a schematic diagram illustrating the voltage value when a water droplet is attached to the touch detection electrode.

  When the target object touches the touch detection electrode 200 and the absolute value of the change rate (increase rate) of the voltage value is equal to or smaller than the absolute value of the predetermined target determination value A1, as shown in FIG. The object determination unit 430 temporarily determines that the object is a user's finger. As described above with reference to FIG. 4, when the touch detection electrode 200 is touched with a finger, the contact area of the finger with the touch detection electrode 200 gradually increases as the fingertip is deformed. This is because the voltage value output from 300 rises more slowly than in the case of water drops.

  Here, the operation determination unit 400 sets the predetermined detection threshold value to “V1” based on the object (user's finger) temporarily determined by the object determination unit 430. Subsequently, as illustrated in FIG. 14A, when the absolute value of the voltage value is equal to or greater than the absolute value of the predetermined detection threshold value V1, the operation determination unit 400 determines that there has been an operation by the user. The touch switch detection device 100 accepts this operation.

  On the other hand, an object contacts the touch detection electrode 200, and as shown in FIG. 14B, the absolute value of the change rate (increase rate) of the voltage value is the absolute value of the predetermined object determination value A2. If it is below and is larger than the absolute value of the object determination value A1, the object determination unit 430 temporarily determines that the object is a water droplet. As described above with reference to FIG. 6, when a water droplet is attached to the touch detection electrode 200, the contact area of the water droplet with respect to the touch detection electrode 200 widens quickly, so that the voltage value output from the detection unit 300 is dry. This is because it rises more rapidly than when it is touched with a finger.

  Here, the operation determination unit 400 sets the predetermined detection threshold value to “V2” based on the object (water droplet) temporarily determined by the object determination unit 430. Subsequently, as shown in FIG. 14B, even when the predetermined detection threshold is set to “V2” that is an absolute value larger than the absolute value of “V1”, the absolute value of the voltage value is predetermined. When the absolute value of the detection threshold V2 is exceeded, the operation determination unit 400 determines that there is an operation by the user, and the touch switch detection device 100 accepts this operation.

  On the other hand, an object contacts the touch detection electrode 200, and as shown in FIG. 14C, the absolute value of the change rate (increase rate) of the voltage value is a predetermined object determination value A2. When the absolute value is equal to or less than the absolute value and larger than the absolute value of the object determination value A1, the object determination unit 430 determines that the object is a water droplet, as in the time chart shown in FIG. Temporarily judge.

  Here, the operation determination unit 400 sets the predetermined detection threshold value to “V2” based on the object (water droplet) temporarily determined by the object determination unit 430. Subsequently, as illustrated in FIG. 14C, when the absolute value of the voltage value is not equal to or greater than the absolute value of the predetermined detection threshold V2, the operation determination unit 400 determines that there is no operation by the user. The touch switch detection device 100 does not accept this operation.

  As described above, the operation determination unit 400 according to the present specific example has a case where the user presses the touch detection electrode 200 with a dry finger, a case where the user presses the touch detection electrode 200 with a wet finger, and a case where a water droplet is attached to the touch detection electrode 200. Can be determined more accurately. Therefore, it is possible to accurately determine whether the operation of the touch switch detection device 100 is due to a human operation or due to water droplet adhesion.

  FIG. 15 is a flowchart illustrating another specific example of the operation of the operation determination unit of this embodiment. The operation of the operation determination unit illustrated in FIG. 15 exemplifies a case where the touch switch detection device 100 is used in a device having an opening / closing valve such as the electromagnetic valve 520 such as the water supply device illustrated in FIG. ing.

  When the electromagnetic valve 520 is open, the water supply device using the touch switch detection device 100 is used by the user, and there is a high possibility that the user's hand is wet. Further, when the electromagnetic valve 520 is open, the device is used by the user, and there is a high possibility that water droplets will be attached to the touch detection electrode 200 due to reflection on the cleaning object. Therefore, the operation determination unit 400 of this specific example estimates that the user is likely to press the touch detection electrode 200 with a wet finger when the electromagnetic valve 520 is open, and the electromagnetic valve opens. The object judgment value and the predetermined detection threshold value can be changed depending on whether the object is closed or closed.

The operation determination unit 400 first determines whether or not the electromagnetic valve 520 is closed (step S402). If the solenoid valve is closed (step S402: YES), a predetermined object determination value is set to _{A1, A2, A n-1} , and _{A n} (step S404), the solenoid valve is opened If it is present (step S402: NO), the predetermined object judgment value is set to B1, B2, B _n-1 , and B _n (step S406). The relationship of the equation (1) is established for the object determination value A, and the following equation is established for the object determination value B and between the object determination value A and the object determination value B: .

| B1 | <| B2 | <... <| _Bn-1 | <| _Bn | Formula (3)

| A1 | <| B1 | Formula (4)

| A2 | <| B2 | Formula (5)

| A _n-1 | <| B _n-1 | Formula (6)

| A _n | <| B _n | Formula (7)

This is because the absolute value of the increase rate of the voltage value is larger when the touch detection electrode 200 is pressed with a wet finger than with a dry finger.

Subsequently, the object determining unit 430 determines the object that has touched the touch detection electrode 200 by performing the operation illustrated in FIG. 12 (step S408). Subsequently, the operation determination unit 400 determines again whether or not the electromagnetic valve 520 is closed (step S410). When the electromagnetic valve 520 is closed (step S410: YES), the predetermined detection thresholds are Va1, Va2, and the like according to the object determined by the object determining unit 430 (step S412, step S414, step S416). va _n-1, or set to va _n (step S418, step S420, step S422, step S424). On the other hand, when the electromagnetic valve 520 is open (step S410: NO), the predetermined detection threshold is set to Vb1, according to the object determined by the object determining unit 430 (step S426, step S428, step S430). vb2, _{Vb n-1,} or set to Vb _n (step S432, step S434, step S436, step S438). Note that the following relational expressions hold for the predetermined detection threshold Va, the predetermined detection threshold Vb, and the predetermined detection thresholds Va and Vb.

| Va1 | <| Va2 | < ··· <| Va n-1 | <| Va n | formula (8)

| Vb1 | <| Vb2 | < ··· <| Vb n-1 | <| Vb n | formula (9)

| Va1 | <| Vb1 | Formula (10)

| Va2 | <| Vb2 | Formula (11)

| Va _n-1 | <| Vb _n-1 | Formula (12)

| Va _n | <| Vb _n | Formula (13)

  Subsequently, it is determined by the operation of the contact determination unit 410 whether or not there has been a user's operation (step S440). When it is determined by the contact determination unit 410 that there is a user operation, the operation determination unit 400 recognizes this determination and ends the operation. On the other hand, when the contact determination unit 410 determines that there is no user operation, the operation determination unit 400 recognizes this determination and ends the operation.

Next, the operation of the operation determination unit of this specific example will be further described with reference to a time chart corresponding to the operation of the flowchart shown in FIG.
FIG. 16 is a schematic view illustrating the voltage value when the electromagnetic valve is opened by pressing the touch detection electrode with a finger. FIG. 16A is a schematic diagram illustrating voltage values when the touch detection electrode is pressed with a dry finger to open the solenoid valve and then pressed with a wet finger to close the solenoid valve. FIG. 16B is a schematic diagram illustrating voltage values when water droplets are attached to the touch detection electrode after the touch detection electrode is pressed with a dry finger to open the solenoid valve.

When the user presses the touch detection electrode 200 with a dry finger to open the electromagnetic valve 520, the electromagnetic valve 520 is closed, so that the operation determination unit 400 sets predetermined object determination values to A1, A2, A _n-1 and _An are set. Subsequently, based on the fact that the absolute value of the change rate (increase rate) of the voltage value is equal to or smaller than the absolute value of the predetermined object determination value A1, the object determination unit 430 causes the object that has contacted the touch detection electrode 200 to be detected. Is temporarily determined to be a user's finger.

  In accordance with the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “Va1”. According to the time chart shown in FIG. 16A, since the absolute value of the voltage value is equal to or larger than the absolute value of the predetermined detection threshold value Va1, the operation determination unit 400 determines that there has been an operation by the user. The touch switch detection device 100 accepts this operation and opens the electromagnetic valve 520.

Here, since solenoid valve 520 is opened, operation determination unit 400 sets predetermined object determination values to B1, B2, B _n−1 , and B _n . Furthermore, the predetermined detection threshold is set to “Vb1” based on the state where the finger or the water droplet is not in contact, that is, the absolute value of the change rate of the voltage value is equal to or less than the absolute value of the predetermined object determination value B1. To do.

  Subsequently, when the user presses the touch detection electrode 200 with a wet finger, the absolute value of the change rate (increase rate) of the voltage value is less than or equal to the absolute value of the predetermined object determination value B2, and the object determination value Based on the fact that it is larger than the absolute value of B1, the object determination unit 430 temporarily determines that the object that has touched the touch detection electrode 200 is a water droplet.

  In accordance with the temporary determination result, the operation determination unit 400 sets the predetermined detection threshold value to “Vb2”. According to FIG. 16A, the absolute value of the voltage value is the absolute value of the predetermined detection threshold value Vb2 even though the predetermined detection threshold value is set to “Vb2” which is an absolute value larger than the absolute value of “Vb1”. That's it. For this reason, the operation determination unit 400 determines that the touch detection electrode 200 does not have water droplets but has been operated by the user, and the touch switch detection device 100 receives this operation and closes the electromagnetic valve 520.

  On the other hand, when the touch detection electrode 200 is pressed with a dry finger to open the electromagnetic valve 520 and then a water droplet is attached to the touch detection electrode 200, the same as the time chart shown in FIG. In addition, although the predetermined detection threshold is set to “Vb2”, as shown in FIG. 16B, the absolute value of the voltage value does not exceed the absolute value of the predetermined detection threshold Vb2. Therefore, the operation determination unit 400 determines that there is no operation by the user, and the touch switch detection device 100 does not accept this operation and does not close the electromagnetic valve 520.

  As described above, the operation determination unit 400 according to the present specific example sets the predetermined object determination value and the predetermined detection threshold according to whether the electromagnetic valve is open or closed. Therefore, a device using the touch switch detection device 100 according to the present specific example can change the determination standard according to the use state of the device, and perform more accurate operation determination in consideration of the influence of water.

  As described above, according to the present embodiment, the predetermined detection threshold is set according to the object temporarily determined to be in contact with the touch detection electrode 200, and the absolute value of the predetermined detection threshold is determined from the detection unit 300. The presence or absence of the user's operation is determined by comparing the magnitude relationship between the absolute value of the output voltage value. Accordingly, the operation determination unit 400 can more accurately determine when the user presses the touch detection electrode 200 with a dry finger, when the user presses the touch detection electrode 200 with a wet finger, and when a water droplet is attached to the touch detection electrode 200. Can be determined. Therefore, it is possible to accurately determine whether the operation of the touch switch detection device 100 is due to a human operation or due to water droplet adhesion.

The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions. As long as the features of the present invention are provided, those skilled in the art appropriately modified the design of the above-described embodiments are also included in the scope of the present invention. For example, in the description of the embodiment of the present invention, the voltage value of the detection output reflecting the change in the electrostatic capacitance has been described as an example in which the voltage value increases when the finger touches and decreases when the finger moves away. However, depending on the configuration of the detection circuit, the voltage value of the detection output can be lowered when the finger is touched, and can be increased when the finger is removed.
Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

The block diagram of the touch switch detection apparatus concerning embodiment of this invention is represented. The block diagram of the water supply apparatus using the touch switch detection apparatus concerning this embodiment is represented. The schematic diagram of the water supply apparatus using the touch switch detection apparatus concerning this embodiment is represented. It is a graph showing the voltage value (actual measurement value) output from the detection part when a touch detection electrode is pushed with the dry finger. It is a graph showing the voltage value (actual measurement value) output from the detection part when the touch detection electrode of this embodiment is pushed with the wet finger. It is a graph showing the voltage value (actual measurement value) output from the detection part when a water droplet adheres to a touch detection electrode. It is a schematic diagram which illustrates the case where a touch detection electrode is pushed with the dry finger. It is a schematic diagram which illustrates the case where the touch detection electrode with a water drop is pushed with a dry finger. It is a schematic diagram which illustrates the case where a touch detection electrode is pushed with a wet finger. It is a schematic diagram which illustrates the case where a water droplet adheres to the touch detection electrode. It is a flowchart figure which illustrates the specific example of operation | movement of the operation determination part of this embodiment. It is a flowchart figure which illustrates the specific example of operation | movement of the target object judgment part of this embodiment. It is a flowchart figure which illustrates the specific example of operation | movement of the contact determination part of this embodiment. It is a time chart for demonstrating the specific example of operation | movement of the operation determination part of this specific example. It is a flowchart figure which illustrates the other specific example of operation | movement of the operation determination part of this embodiment. It is a schematic diagram which illustrates the voltage value at the time of pushing a touch detection electrode with a finger | toe and opening an electromagnetic valve.

Explanation of symbols

100, 100a, 100b, 100c Touch switch detection device, 200 touch detection electrode, 300 detection unit, 310 oscillation unit, 320 voltage conversion unit, 400 operation determination unit, 410 contact determination unit, 430 object determination unit, 500 water supply device, 510 control unit, 520 solenoid valve, 530 water outlet

Claims (5)

A touch detection electrode that detects a change in capacitance due to the approach or contact of an object; and
A detection unit that outputs a detection output reflecting the change in the capacitance;
An operation determination unit that determines the presence or absence of a user's operation based on the detection output;
With
The operation determination unit is
An object determination unit for tentatively determining the object based on whether or not a change rate of the detection output at the start of detection is equal to or less than an object determination value;
A contact determination unit that determines the contact of the user based on whether the detection output is equal to or greater than a detection threshold;
Have
The operation determination unit sets the detection output as the detection threshold when the object determination unit temporarily determines that the object is the user when the object is temporarily determined to be the user , When the object determination unit tentatively determines that the object is a water droplet, a value larger than the detection output when tentatively determined that the object is the user is set as the detection threshold, and the detection output is A touch switch detection device that determines whether or not there is an operation by the user based on whether or not the detection threshold is exceeded.   The touch switch detection device according to claim 1, wherein when the detection output is equal to or greater than the detection threshold, the operation determination unit determines that the user has performed an operation. The touch switch detection device according to claim 1 or 2 ,
A solenoid valve that opens and closes the water supply flow path;
A water discharge port for discharging water supplied through the water supply channel;
Based on the determination of the operation determination unit, a control unit that controls the operation of the solenoid valve;
A water supply apparatus comprising: The water supply apparatus according to claim 3 , wherein at least one of the value of the object determination value and the value of the detection threshold value is changed according to an open / close state of the electromagnetic valve. The operation determination unit, when the solenoid valve is in the open state, according to claim 4, wherein the solenoid valve and sets the object determination value and the detection threshold with a value larger than that of the closed state Water supply apparatus of description.

Images