JP2009238701A - Touch switch detector, and water supply system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a touch switch detector capable of accurately determining an operation of a person and adhesion of a water drop and preventing from spoiling operation feeling, and to provide a water supply system using the touch switch detector. <P>SOLUTION: The touch switch detector comprises a plurality of contact electrodes capable of touching by a user, a plurality of touch detection electrodes arranged by respectively facing the plurality of contact electrodes via an insulator, and an operation determination section for determining existence of an operation of a user on the basis of detection output reflecting electrostatic capacity between the contact electrode and the touch detection electrode. The operation determination section set up a detection threshold used as a determination criterion for determining existence of an operation of a user on the basis of the number of contact electrodes determined that a target keeps in contact with any contact electrode. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  Aspects of the present invention generally relate to a touch switch detection device, and more particularly, to a capacitive touch switch detection device and a water supply device using the same.

  In the capacitive touch switch detection device, for example, a touch detection electrode is provided on the back surface of a touch panel made of an insulator. Here, as one method for improving the detection sensitivity, an electrode (counter electrode) facing the touch detection electrode via an insulator (touch panel) is provided on the surface of the insulator, and the area of the counter electrode is increased. A method is mentioned. When the counter electrode is not provided, the capacitance changes depending on the contact area of the finger touching the insulator, and thus it is necessary to press the finger against the insulator. On the other hand, when the counter electrode is provided, the finger touches an area corresponding to the area of the counter electrode just by touching a part of the counter electrode. Even if it is not applied, the detection sensitivity is improved.

  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 vicinity of the touch detection electrode. For this reason, if a counter electrode facing the touch detection electrode is provided on the surface of the insulator and the area of the counter electrode is increased, a malfunction may occur when a water droplet or the like is attached.

  Therefore, in order to prevent malfunctioning even if a small animal or a water droplet touches the electrode part, there is one in which the electrode part is electrically divided into a plurality (for example, see Patent Document 1). In the device described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-50635), a user touches a groove provided between divided electrode parts, that is, a user straddles the divided electrode parts. By touching, it is recognized that the user has operated. Therefore, even if the user touches any one of the divided electrode portions, it is not recognized that the user has operated.

However, the device described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-50635) may malfunction if water droplets adhere to the divided electrode portions and the electrode portions are electrically connected to each other. There is. In addition, even if the user touches a part of the divided electrode part, this device does not detect the user's operation, and there is a risk of impairing the operation feeling. Furthermore, when used for a long period of time, at least one of the electrode portions is rubbed and becomes small, and the detection sensitivity is lowered.
JP 2005-50635 A

  An aspect of the present invention has been made based on recognition of such a problem, and can accurately determine a human operation and adhesion of water droplets or can prevent a feeling of operation from being impaired. A detection device and a water supply device using the same are provided.

  According to one aspect of the present invention, a plurality of contact electrodes that can be contacted by a user, a plurality of touch detection electrodes provided to face each of the plurality of contact electrodes via an insulator, and the contact electrodes And an operation determination unit that determines the presence or absence of a user's operation based on a detection output reflecting a capacitance between the touch detection electrode and the touch detection electrode, and the operation determination unit is in contact with an object Based on the number of contact electrodes determined to be, a touch switch detection device is provided that sets a detection threshold that is a determination criterion for determining the presence or absence of a user's operation.

  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 which can judge a user's operation and adhesion of a water drop exactly, or can keep a feeling of operation, and a water supply apparatus using the same are provided. Is done.

A first invention includes a plurality of contact electrodes that can be contacted by a user, a plurality of touch detection electrodes provided to face each of the plurality of contact electrodes via an insulator, the contact electrodes, and the touch An operation determination unit that determines the presence / absence of a user's operation based on a detection output that reflects capacitance between the detection electrode and the detection electrode, and the operation determination unit determines that the object is in contact with the detection electrode. The touch switch detection device is characterized in that, based on the number of contact electrodes, a detection threshold is set as a determination criterion for determining whether or not the user has performed an operation.
According to this touch switch detection device, it is possible to prevent malfunction due to water droplets while maintaining a good operation regardless of the location where the contact electrode is touched or the way of pressing. Further, even when a part of the contact electrode is touched, it is possible to accurately determine a human operation. Therefore, the operational feeling is not impaired.

According to a second invention, in the first invention, the operation determination unit determines that the user's operation has been performed when the detection output is equal to or greater than the detection threshold. Device.
According to this touch switch detection device, since the detection threshold is set based on the number of contact with the contact electrode, the absolute value is detected without performing calculation according to the analog value of the detection output of the touch detection electrode. Only when the absolute value of the threshold value is exceeded, it can be determined that there has been a user operation. Therefore, it is possible to more accurately determine human operation and adhesion of water droplets simply without performing complicated signal processing.

According to a third invention, in the first or second invention, the operation determination unit sets the detection threshold value larger as the number of contact electrodes determined to be in contact with an object is larger. This is a touch switch detection device.
According to this touch switch detection device, the larger the number of contact with the contact electrode, the larger the capacitance between the contact electrode and the touch detection electrode, so that the detection threshold value is corrected. Thereby, it is possible to prevent a malfunction due to water droplets while maintaining a good operation regardless of the place where the contact electrode is touched or the pressing method.

4th invention is the touch switch detection apparatus of any one of the 1st-3rd invention, the solenoid 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, And a control unit that controls the operation of the solenoid valve based on the determination of the operation determination unit.
According to this water supply apparatus, even when a water droplet is applied to the touch detection electrode, it is possible to perform a water discharging operation by making a more accurate operation determination.

A fifth aspect of the present invention is the water supply apparatus according to the fourth aspect of the invention, wherein the operation determination unit changes the setting of the detection threshold according to the open / close state of the electromagnetic valve.
According to this water supply apparatus, since a detection threshold value can be changed according to the state of a device on which water droplets are likely to be applied, more accurate operation determination can be performed.

According to a sixth aspect of the present invention, in the fifth aspect of the invention, the operation determination unit sets a detection threshold value larger when the electromagnetic valve is in an open state than when the electromagnetic valve is in a closed state. Device.
According to this water supply device, when the solenoid 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 the water is stopped. 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 schematic view illustrating a touch switch unit of a touch switch detection device according to an embodiment of the invention. 1A is a schematic view of the touch switch unit viewed from the front side, and FIG. 1B is a schematic view of the touch switch unit viewed from the side.

  The touch switch unit 200 includes contact electrodes 210a, 210b, 210c, and 210d, touch detection electrodes 220a, 220b, 220c, and 220d, and a touch panel 240. Contact electrodes 210 a, 210 b, 210 c, and 210 d are provided on the surface side of touch panel 240. Further, the touch detection electrodes 220a, 220b, 220c, and 220d are on the back surface side of the touch panel 240 at positions facing the contact electrodes 210a, 210b, 210c, and 210d (positions immediately below in FIG. 1B). Is provided. The touch panel 240 is made of an electrical insulator such as plastic or glass.

  The contact electrodes 210a, 210b, 210c, and 210d are portions that the user directly touches with a finger or the like. On the other hand, since the touch detection electrodes 220a, 220b, 220c, and 220d are provided on the back surface side of the touch panel 240, they are not directly touched by the user. Here, since the electrodes of the contact electrodes 210a, 210b, 210c, and 210d and the touch detection electrodes 220a, 220b, 220c, and 220d are opposed to each other with the touch panel 240 interposed therebetween, a predetermined capacitance is obtained. The capacitor which has is comprised.

  When the object is in contact with at least one of the contact electrodes 210a, 210b, 210c, and 210d, the capacitance between the contact electrode in contact with the touch detection electrode facing the contact electrode Changes. Thereby, the touch switch detection device can determine which of the contact electrodes 210a, 210b, 210c, and 210d the object is in contact with. The touch switch detection device of the present embodiment can set a detection threshold that is a determination criterion for determining whether or not there is a user's operation based on the number of contact electrodes determined to be in contact with an object.

  On the other hand, a high frequency voltage is applied to the touch detection electrodes 220a, 220b, 220c, and 220d from an oscillation circuit, as will be described in detail later. The voltage amplitude of the high-frequency voltage changes according to the change in capacitance between the contact electrode with which the object is in contact and the touch detection electrode facing the contact electrode, and as a detection signal (detection output) Is output. Therefore, the touch switch detection device of the present embodiment can determine that the user has operated when the detection output output from the touch detection electrode is equal to or greater than the detection threshold.

FIG. 2 is a schematic view illustrating a touch switch detection device according to this embodiment and a water supply device using the same.
The touch switch detection device 100 according to the present embodiment includes a touch switch unit 200 (see FIG. 1) and an operation determination unit 300 that determines the presence / absence of a user's operation. The operation determination unit 300 includes a switching circuit 310, an oscillation circuit 320, a detection circuit 330, an LPF (Low Pass Filter) 340, an amplification circuit 350, a control unit 360, and an electromagnetic valve drive circuit 370. Have.

  The switching circuit 310 receives instructions from the control unit 360 and switches the circuits of the touch detection electrodes 220a, 220b, 220c, and 220d at predetermined time intervals. The oscillation circuit 320 outputs a high-frequency signal, forms a high-frequency voltage based on the high-frequency signal, and applies it to the touch detection electrodes 220a, 220b, 220c, and 220d. When the object is not in contact with any of the contact electrodes 210a, 210b, 210c, and 210d, the voltage amplitude of the high-frequency voltage applied to the touch detection electrodes 220a, 220b, 220c, and 220d does not change, and the detection circuit 330 is output.

  On the other hand, when the object is in contact with at least one of the contact electrodes 210a, 210b, 210c, and 210d, the contact electrode with which the object is in contact and the touch detection electrode facing the contact electrode And the capacitance between the two changes. As a result, the voltage amplitude of the high-frequency voltage applied to the touch detection electrode facing the contact electrode with which the object is in contact changes according to the change in capacitance and is output to the detection circuit 330. The detection circuit 330 outputs a voltage value applied to the touch detection electrodes 220a, 220b, 220c, and 220d to the LPF 340 as a detection signal.

  The detection signal output to the LPF 340 is output to the amplifier circuit 350 after the voltage in the high frequency band is removed. The detection signal output to the amplifier circuit 350 is output to the control unit 360 in an amplified state. The control unit 360 converts this detection signal (detection output) into an A / D (analog / digital converter), and gives a control command to the solenoid valve drive circuit 370 based on the conversion result.

  Here, when an object such as a finger or a water droplet touches the contact electrodes 210a, 210b, 210c, and 210d, the contact area of the object with respect to the contact electrode increases. Therefore, the output from the touch detection electrode that faces the contact electrode. The voltage value to be reduced will decrease. Thereafter, this voltage value is inverted and amplified by the amplifier circuit 350. Therefore, it is output from the touch detection electrode facing the contact electrode touched by the object, and the voltage value (detection output) via the amplifier circuit 350 increases. When the amplifier circuit 350 performs non-inverting amplification instead of inverting amplification, when the target object touches the contact electrodes 210a, 210b, 210c, and 210d, the voltage value via the amplifier circuit 350 decreases. That is, whether or not the voltage value through the amplifier circuit 350 when the object touches the contact electrode is increased depends on whether the amplifier circuit 350 performs inverting amplification or non-inverting amplification. Hereinafter, a case where the amplifier circuit 350 performs inverting amplification will be described as an example.

  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 illustrated in FIG. 2 includes a touch switch detection device 100, a solenoid valve 520, and a water discharge port 530. Here, the touch switch unit 200 can have a function as, for example, a “water discharge / water stop switch”.

  The control unit 360 determines the presence / absence of a user's operation based on the signals output from the touch detection electrodes 220a, 220b, 220c, and 220d, and instructs the electromagnetic valve drive circuit 370 to perform a water discharge operation. The electromagnetic valve drive circuit 370 drives the opening / closing operation of the electromagnetic valve 520 based on the instruction output from the control unit 360. Thereby, the water discharge from the water outlet 530 of the water supply apparatus 500 is controlled.

Hereinafter, a specific example of the operation of the touch switch detection device of this embodiment will be described with reference to the drawings.
FIG. 3 is a schematic view illustrating a specific example when the user presses two contact electrodes. 3A is a schematic view of the touch switch unit as viewed from the front surface side, and FIG. 3B is a schematic diagram of the touch switch unit as viewed from the side surface.
FIG. 4 is a schematic diagram for explaining changes in capacitance and detection output when the user presses two contact electrodes. 4A is a schematic diagram for explaining a change in capacitance, and FIG. 4B is a schematic diagram for explaining a change in detection output.

  As shown in FIGS. 3A and 3B, when the user presses the contact electrodes 210a and 210b with a finger, the contact electrode 210a and the contact electrode 210b are short-circuited by the finger. Therefore, as shown in FIG. 4A, the area of the contact electrode touched by the user can be considered to be the same as the area of the contact electrode 210e, which is the sum of the contact electrode 210a and the contact electrode 210b. . That is, if the contact electrode 210a and the contact electrode 210b have the same area, it can be considered that the area of the contact electrode 210e is twice the area of the contact electrode 210a or the contact electrode 210b.

  Further, when the user touches the contact electrodes 210a and 210b, it can be considered that the human body capacitor 250a is connected in series to the contact electrode 210e. The capacity of the human body is larger than that of water drops, and the user is also in contact with the ground. For this reason, the capacitance between the contact electrode 210a and the touch detection electrode 220a increases due to the increase in the apparent area of the contact electrode 210a and the connection of the capacitor 250a of the human body. The same applies to the capacitance between the contact electrode 210b and the touch detection electrode 220b.

  The capacitance between the contact electrode 210a and the touch detection electrode 220a and the capacitance between the contact electrode 210b and the touch detection electrode 220b become substantially the same, so that the touch switch detection according to the present embodiment is performed. The apparatus can detect that the contact electrode 210a and the contact electrode 210b are connected. That is, the touch switch detection device can detect that the number of contact electrodes in contact with the object is two.

  At this time, the touch switch detection device according to the present embodiment determines that the contact electrodes in contact with the object are the contact electrode 210a and the contact electrode 210b, and uses the contact electrodes based on the number (two) of the contact electrodes. A detection threshold is set as a criterion for determining whether or not there is an operation by the user. The detection threshold in this case is set to “medium (V2a)” as will be described later with reference to FIG.

  On the other hand, as the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a increases, as shown in FIG. 4B, the voltage value of the detection output output from the touch detection electrode 220a increases. . Similarly, the voltage value of the detection output output from the touch detection electrode 220b also increases. Here, as illustrated in FIG. 4B, when the voltage value of the detection output output from the touch detection electrodes 220 a and 220 b is equal to or higher than the detection threshold, the operation determination unit 300 performs the user operation. The touch switch detection device 100 accepts this operation. On the other hand, when the voltage value of the detection output output from the touch detection electrodes 220a and 220b does not exceed the detection threshold value, the operation determination unit 300 determines that there is no user operation, and the touch switch The detection apparatus 100 does not accept this operation.

FIG. 5 is a schematic view illustrating a specific example when the user presses four contact electrodes. 5A is a schematic diagram of the touch switch unit viewed from the front surface side, and FIG. 5B is a schematic diagram of the touch switch unit viewed from the side surface.
FIG. 6 is a schematic diagram for explaining changes in capacitance and detection output when the user presses four contact electrodes. FIG. 6A is a schematic diagram for explaining the change in capacitance, and FIG. 6B is a schematic diagram for explaining the change in detection output.

  As shown in FIGS. 5 (a) and 5 (b), when the user presses the contact electrodes 210a, 210b, 210c, 210d with a finger, as described above with reference to FIG. 210b, 210c and 210d are short-circuited by a finger. Therefore, as shown in FIG. 6A, it is considered that the area of the contact electrode touched by the user is the same as the area of the contact electrode 210f that is the sum of the contact electrodes 210a, 210b, 210c, and 210d. it can. That is, if the areas of the contact electrodes 210a, 210b, 210c, and 210d are all the same, the area of the contact electrode 210f can be considered to be four times the area of each of the contact electrodes 210a, 210b, 210c, and 210d. .

  Further, as described above with reference to FIG. 4, when the user touches the contact electrodes 210a, 210b, 210c, and 210d, it can be considered that the human body capacitor 250a is connected in series to the contact electrode 210f. . For this reason, the capacitance between the contact electrode 210a and the touch detection electrode 220a increases due to the increase in the apparent area of the contact electrode 210a and the connection of the capacitor 250a of the human body.

  At this time, the apparent area of the contact electrode 210a is larger than the apparent area when two contact electrodes are pressed (see FIG. 3 and FIG. 4). And it becomes larger than the electrostatic capacitance in the specific example illustrated in FIG. This is because the capacitance between the contact electrode 210b and the touch detection electrode 220b, the capacitance between the contact electrode 210c and the touch detection electrode 220c, and the capacitance between the contact electrode 210d and the touch detection electrode 220d. The same applies to.

  The capacitance between the contact electrode 210a and the touch detection electrode 220a, the capacitance between the contact electrode 210b and the touch detection electrode 220b, and the capacitance between the contact electrode 210c and the touch detection electrode 220c Since the capacitance between the contact electrode 210d and the touch detection electrode 220d is substantially the same, the touch switch detection device of the present embodiment is connected to the contact electrodes 210a, 210b, 210c, and 210d. Can be detected. That is, the touch switch detection device can detect that the number of contact electrodes in contact with the object is four.

  At this time, the touch switch detection device according to the present embodiment determines that the contact electrodes in contact with the object are the contact electrodes 210a, 210b, 210c, and 210d, and based on the number of contact electrodes (four). Then, a detection threshold value is set, which is a criterion for determining the presence / absence of the user's operation. The detection threshold in this case is set to “high (V4a)” as described later with reference to FIG.

  On the other hand, as the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a increases, as shown in FIG. 6B, the voltage value of the detection output output from the touch detection electrode 220a increases. . As described above, the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a is larger than the electrostatic capacitance when two contact electrodes are pressed (see FIGS. 3 and 4), so that the detection output Is also larger than the specific examples illustrated in FIGS. 3 and 4.

  Therefore, although the detection threshold is set to “high (V4a)”, the voltage value of the detection output when the user presses four contact electrodes is equal to or higher than the detection threshold. Therefore, in this specific example, the operation determination unit 300 determines that there has been a user's operation, and the touch switch detection device 100 can accept this operation.

FIG. 7 is a schematic view illustrating a specific example when the user presses one contact electrode. FIG. 7A is a schematic view of the touch switch unit viewed from the front side, and FIG. 7B is a schematic view of the touch switch unit viewed from the side.
FIG. 8 is a schematic diagram for explaining changes in capacitance and detection output when the user presses one contact electrode. FIG. 8A is a schematic diagram for explaining a change in capacitance, and FIG. 8B is a schematic diagram for explaining a change in detection output.

  As shown in FIGS. 7A and 7B, when the user presses only the contact electrode 210a with a finger, the contact electrode 210a is not short-circuited with other contact electrodes. Therefore, the apparent area of the contact electrode 210a is the same as the area of the contact electrode 210a.

  In addition, as described above with reference to FIG. 4, when the user is touching the contact electrode 210a, it can be considered that the human body capacitor 250a is connected in series to the contact electrode 210a. Therefore, the capacitance between the contact electrode 210a and the touch detection electrode 220a is increased by connecting the capacitor 250a of the human body.

  At this time, the apparent area of the contact electrode 210a is apparent when two contact electrodes are pressed (see FIGS. 3 and 4) or when four contact electrodes are pressed (see FIGS. 5 and 6). Therefore, the capacitance in this specific example is smaller than the capacitance in those specific examples. Therefore, as the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a increases, as shown in FIG. 8B, the voltage value of the detection output output from the touch detection electrode 220a increases. However, it is not as high as the voltage values shown in FIG. 4B and FIG. 6B.

  On the other hand, since only the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a is increased, in the touch switch detection device of the present embodiment, only the contact electrode 210a is in contact with the object. Judge. Based on this determination result, the touch switch detection device sets a detection threshold value that is a determination criterion for determining whether or not there is an operation by the user. In this case, the detection threshold is set to “low (V1a)” as described later with reference to FIG.

  Therefore, the voltage value of the detection output output from the touch detection electrode 220a is not as high as the voltage values illustrated in FIG. 4B and FIG. 6B, but the detection threshold is “low (V1a)”. Therefore, the voltage value of the detection output when the user presses only the contact electrode 210a is equal to or higher than the detection threshold. Therefore, also in the case of this specific example, the operation determination unit 300 determines that there is a user's operation, and the touch switch detection device 100 can accept this operation.

  As described above, the touch switch of the present embodiment can be used regardless of whether the user has pressed two contact electrodes, pressed four contacts, or pressed only one. The detection device can detect the operation of the user. That is, even when a part of the contact electrode is touched, the user's operation can be detected. Therefore, the touch switch detection device of the present embodiment can prevent the operational feeling from being impaired.

  Further, even when at least one of the contact electrodes 210a, 210b, 210c, and 210d is rubbed and becomes small due to long-term use and the detection sensitivity is lowered, the touch switch detection device of the present embodiment has a substantial object. The detection threshold value can be set by judging the number of contact electrodes in contact with the electrode. Therefore, it is possible to prevent the operation feeling from being impaired without lowering the detection sensitivity.

Next, a specific example of the operation when water droplets are attached to the touch switch detection device of this embodiment will be described with reference to the drawings.
FIG. 9 is a schematic view illustrating a specific example when water droplets are attached to four contact electrodes. FIG. 9A is a schematic view of the touch switch unit viewed from the front side, and FIG. 9B is a schematic view of the touch switch unit viewed from the side.
FIG. 10 is a schematic diagram for explaining changes in capacitance and detection output when water droplets are attached to four contact electrodes. FIG. 10A is a schematic diagram for explaining a change in capacitance, and FIG. 10B is a schematic diagram for explaining a change in detection output.

  As shown in FIG. 9A and FIG. 9B, when the water droplet 410 is applied across the contact electrodes 210a, 210b, 210c, and 210d, as described above with reference to FIG. 210 b, 210 c, and 210 d are short-circuited by the water droplet 410. Therefore, as shown in FIG. 10A, the area of the contact electrode with the water droplet 410 is considered to be the same as the area of the contact electrode 210f, which is the sum of the contact electrodes 210a, 210b, 210c, and 210d. Can do. That is, if the areas of the contact electrodes 210a, 210b, 210c, and 210d are all the same, the area of the contact electrode 210f can be considered to be four times the area of each of the contact electrodes 210a, 210b, 210c, and 210d. .

  In addition, when the water droplet 410 is attached to the contact electrodes 210a, 210b, 210c, and 210d, it can be considered that the water droplet capacity 250b is connected in series to the contact electrode 210f. The volume 250b of water droplets with respect to the ground is smaller than the volume 250a of human bodies with respect to the ground. Therefore, the capacitance between the contact electrode 210a and the touch detection electrode 220a increases due to the increase in the apparent area of the contact electrode 210a and the connection of the water droplet capacity 250b. Is not as large as when four contact electrodes are pressed. This is because the capacitance between the contact electrode 210b and the touch detection electrode 220b, the capacitance between the contact electrode 210c and the touch detection electrode 220c, and the capacitance between the contact electrode 210d and the touch detection electrode 220d. The same applies to.

  The capacitance between the contact electrode 210a and the touch detection electrode 220a, the capacitance between the contact electrode 210b and the touch detection electrode 220b, and the capacitance between the contact electrode 210c and the touch detection electrode 220c Since the electrostatic capacitance between the contact electrode 210d and the touch detection electrode 220d is substantially the same, the touch switch detection device of the present embodiment is connected to the contact electrodes 210a, 210b, 210c, and 210d. Can be detected. That is, the touch switch detection device can detect that the number of contact electrodes in contact with the object is four.

  At this time, the touch switch detection device according to the present embodiment determines that the contact electrodes in contact with the object are the contact electrodes 210a, 210b, 210c, and 210d, and based on the number of contact electrodes (four). The detection threshold is set to “high (V4a)”.

  On the other hand, as the electrostatic capacitance between the contact electrode 210a and the touch detection electrode 220a increases, as shown in FIG. 10B, the voltage value of the detection output output from the touch detection electrode 220a increases. However, it is not as high as when the user presses four contact electrodes. As described above, the water droplet capacity 250b is smaller than the human body capacity 250a, and the capacitance between the contact electrode 210a and the touch detection electrode 220a is determined by the user pressing the four contact electrodes. This is because it is not as big as the case. The same applies to the voltage value of the detection output output from the touch detection electrodes 220b, 220c, and 220d.

  Therefore, the detection threshold is set to “high (V4a)”, and the voltage value of the detection output output from the touch detection electrode is not as high as when the user presses four contact electrodes. The voltage value does not exceed the detection threshold. Therefore, in this specific example, the operation determination unit 300 determines that there is no user operation, and the touch switch detection device 100 does not accept this operation.

  Further, even when the detection threshold is set to “high (V4a)” with the water droplet 410 remaining on the contact electrodes 210a, 210b, 210c, and 210d, the user presses one contact electrode. Sometimes the user is equivalent to pushing four contact electrodes. Therefore, the voltage value of the detection output is equal to or higher than the detection threshold, and the touch switch detection device 100 can accept this operation. Therefore, the touch switch detection device can prevent the operational feeling from being impaired.

FIG. 11 is a table showing the relationship between the detection threshold set by the touch switch detection device of the present embodiment and the number of contact electrodes in contact with the object.
As described above, the touch switch detection device of the present embodiment can set the detection threshold based on the number of contact electrodes determined to be in contact with the object. Here, the touch switch detection apparatus can determine the detection threshold by referring to a table shown in FIG. 11 while avoiding complicated calculations. That is, the detection threshold can be determined with reference to a table obtained from the number of contact electrodes determined to be in contact with the object. Such a table can be stored as data in a memory provided in the control unit 360, for example.

When the number of contact electrodes in contact with the object is four, the detection threshold is set to “V4a (high)”. That is, the detection threshold value is set to “V4a (high)” depending on the capacities of the four contact electrodes and the human body with respect to the ground. On the other hand, when the number of contact electrodes in contact with the object is one, the detection threshold is set to “V1a (low)”. That is, the detection threshold is set to “V1a (low)” depending on the capacity of one contact electrode and the human body with respect to the ground. As described above, as the number of contact electrodes in contact with an object increases, the apparent area of the contact electrode increases, and the capacitance between the contact electrode and the touch detection electrode increases. It is to become. For the detection threshold, the following relational expression is established.

V1a <V2a <V3a <V4a Formula (1)

  Even if the detection threshold is set to “V4a”, if the user touches the four contact electrodes, the capacitance between the contact electrodes and the touch detection electrodes is increased to output from the touch detection electrodes. The detected output voltage value also increases. Therefore, this voltage value can be greater than or equal to the detection threshold. In contrast, when the user touches only one contact electrode, the detection output voltage value output from the touch detection electrode is small, but the detection threshold is set to “V1a”. Even in this case, the voltage value of the detection output can be equal to or higher than the detection threshold.

  Therefore, the touch switch detection device of the present embodiment can accurately determine human operation and water droplet adhesion by setting the detection threshold value larger as the number of contact electrodes in contact with an object increases. it can. Further, even when a part of the contact electrode is touched, the user's operation can be detected. Therefore, the touch switch detection device of the present embodiment can prevent the operational feeling from being impaired.

As described above, the touch switch detection device 100 according to the present embodiment is used in, for example, a water supply device. 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. In addition, 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 switch unit 200 due to reflection on the cleaning object. Therefore, when the electromagnetic valve 520 is open, the touch switch detection device 100 according to the present embodiment estimates that the user is likely to press the touch detection electrode with a wet finger, and the electromagnetic valve 520 is closed. It is possible to set a detection threshold larger than the detection threshold in the case of That is, when the electromagnetic valve 520 is open, a detection threshold that satisfies the following relational expression can be set.

V1b <V2b <V3b <V4b Formula (2)

V1a <V1b Formula (3)

V2a <V2b Formula (4)

V3a <V3b Formula (5)

V4a <V4b Formula (6)

  Thereby, even if a water droplet is applied to the contact electrode, it is possible to make a more accurate operation determination and perform a water discharging operation. In addition, when the solenoid valve is open, it is easy to get water on the contact electrode, and it is often operated with wet hands when water stops, so consider the influence of water droplets on the operation of the touch detection electrode. Thus, more accurate operation determination can be performed.

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, the shape, dimensions, material, arrangement, and the like of the contact electrode and the touch detection electrode are not limited to those illustrated, and can be changed as appropriate. In other words, the number of contact electrodes and touch detection electrodes is not limited to four, but can be five or more. Or two or three may be sufficient. Furthermore, the shapes of the contact electrode and the touch detection electrode are not limited to rectangles, but may be triangular, trapezoidal, fan-shaped, or the like.
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.

It is a schematic diagram which illustrates the touch switch part of the touch switch detection apparatus concerning embodiment of this invention. It is a schematic diagram which illustrates the touch switch detection apparatus concerning this embodiment, and the water supply apparatus using the same. It is a schematic diagram which illustrates the example in case a user pushes two contact electrodes. It is a schematic diagram for demonstrating the change of an electrostatic capacitance and a detection output when a user pushes two contact electrodes. It is a schematic diagram which illustrates the example in case a user pushes four contact electrodes. It is a schematic diagram for demonstrating the change of an electrostatic capacitance and detection output when a user pushes four contact electrodes. It is a schematic diagram which illustrates the specific example at the time of a user pressing one contact electrode. It is a schematic diagram for demonstrating the change of an electrostatic capacitance and a detection output when a user pushes one contact electrode. It is a schematic diagram which illustrates the example in case a water drop adheres to four contact electrodes. It is a schematic diagram for demonstrating the change of an electrostatic capacitance and detection output when a water droplet adheres to four contact electrodes. It is the table showing the relationship between the detection threshold value which the touch switch detection apparatus of this embodiment sets, and the number of the contact electrodes which the target object is contacting.

Explanation of symbols

  100 touch switch detection device, 200 touch switch unit, 210a, 210b, 210c, 210d, 210e, 210f contact electrode, 220a, 220b, 220c, 220d touch detection electrode, 240 touch panel, 250a human body capacity, 250b water drop capacity, 300 Operation determination unit, 310 switching circuit, 320 oscillation circuit, 330 detection circuit, 340 LPF, 350 amplification circuit, 360 control unit, 370 solenoid valve drive circuit, 410 water droplet, 500 water supply device, 520 solenoid valve, 530 water outlet

Claims (6)

A plurality of contact electrodes that can be contacted by a user;
A plurality of touch detection electrodes provided to face each of the plurality of contact electrodes via an insulator;
An operation determination unit that determines the presence / absence of a user's operation based on a detection output that reflects a capacitance between the contact electrode and the touch detection electrode;
With
The operation determination unit sets a detection threshold that is a determination criterion for determining the presence / absence of a user's operation based on the number of contact electrodes determined to be in contact with an object. apparatus.   The touch switch detection device according to claim 1, wherein the operation determination unit determines that the user has performed an operation when the detection output is equal to or greater than the detection threshold.   The touch switch detection device according to claim 1, wherein the operation determination unit sets the detection threshold value larger as the number of contact electrodes determined to be in contact with an object is larger. The touch switch detection device according to any one of claims 1 to 3,
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 device according to claim 4, wherein the operation determination unit changes the setting of the detection threshold according to an open / close state of the electromagnetic valve.   The water supply device according to claim 5, wherein the operation determination unit sets a detection threshold value larger when the electromagnetic valve is in an open state than when the electromagnetic valve is in a closed state.

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