JP2022090598A - Toilet seat device - Google Patents

Abstract

To provide a toilet seat device capable of suppressing the occurrence of erroneous detection of a human body by noise.SOLUTION: The toilet seat device is provided. It includes a toilet seat, a detection electrode in which electrostatic capacity changes according to seating of a human body on the toilet seat, electrostatic capacity detection means having an input terminal connected electrically to the detection electrode to detect the electrostatic capacity of the detection electrode, a control part for determining the existence/nonexistence of the seating of the human body on the basis of a detection result of the electrostatic capacity detection means, and overvoltage detection means for detecting overvoltage in the input terminal. When the overvoltage detection means detects the overvoltage, the electrostatic capacity detection means is restarted after temporarily stopping the detection of the electrostatic capacity.SELECTED DRAWING: Figure 2

Description

Aspects of the present invention generally relate to toilet seat devices.

There is a capacitance type human body detection sensor that detects the human body by changing the capacitance with the presence or absence of the human body. It has been proposed to use such a capacitance type human body detection sensor for a toilet seat device. For example, in the seating detection device for a toilet seat of Patent Document 1, a heat-conducting conductor (aluminum foil) attached to a heater wire provided on the toilet seat is used as an electrode, and a change in capacitance is detected to reach the toilet seat. Detects sitting on the human body.
In a toilet seat device equipped with a capacitance type sensor, noise may cause erroneous detection of the human body. For example, the detection accuracy of the human body may decrease due to noise in the power supply line of the toilet seat device.

Japanese Unexamined Patent Publication No. 6-138247

The present invention has been made based on the recognition of such a problem, and an object of the present invention is to provide a toilet seat device capable of suppressing false detection of the human body due to noise.

The first invention has a toilet seat, a detection electrode whose capacitance changes according to the seating of a human body on the toilet seat, and an input terminal electrically connected to the detection electrode. Capacitance detecting means for detecting capacitance, a control unit for determining whether or not the human body is seated based on the detection result of the capacitance detecting means, and overvoltage detecting means for detecting overvoltage at the input terminal. When the overvoltage detecting means detects the overvoltage, the capacitance detecting means is a toilet seat device characterized in that the detection of the capacitance is paused and then restarted.

According to this toilet seat device, even if an overvoltage occurs in the input terminal due to noise such as a power supply, the capacitance detecting means suspends the detection of the capacitance, thereby suppressing the occurrence of false detection due to the noise. can.

According to a second aspect of the invention, in the first invention, the capacitance detecting means includes an integrating means for storing electric charges discharged from the detection electrode, a first switch connected to a predetermined voltage, the input terminal, and the above. A first state in which the first switch is on, the second switch is off, and the detection electrode is charged to the predetermined voltage, and the first switch has a second switch connected to the integrating means. Is off and the second switch is on and the second state of discharging the detection electrode is alternately repeated, and the integrating means performs the switching operation in the second state repeated by the switching operation. The control unit stores the electric charge discharged from the detection electrode, determines whether or not the human body is seated according to the electric charge accumulated in the integrating means, and when the overvoltage detecting means detects the overvoltage, the electrostatic charge is generated. The capacity detecting means is a toilet seat device characterized in that the switching operation is temporarily stopped, the first switch and the second switch are put into the first state, and then the switching operation is restarted.

According to this toilet seat device, when an overvoltage occurs in the input terminal due to noise such as a power supply, the capacitance detecting means suspends the switching operation and enters the first state. As a result, the integration of the integrating means (accumulation of electric charge) is interrupted, so that it is possible to suppress the occurrence of a large error in the integrated value due to noise. Therefore, it is possible to suppress the occurrence of false detection due to noise.

A third aspect of the invention is the toilet seat device according to the second aspect, further comprising an off-delay means for continuing the first state for a predetermined time when the overvoltage detecting means detects the overvoltage. ..

According to this toilet seat device, since the integration of the integrating means is continuously interrupted by the continuation of the first state, it is possible to further suppress the occurrence of erroneous detection due to noise.
For example, a state in which noise is generated in the input terminal may continue due to the inclusion of a capacitance component or an inductive component in the circuit of the toilet seat device. That is, since the circuit of the toilet seat device has a capacitance component and an inductive component, even if the applied overvoltage is momentary, the potential fluctuation due to noise does not immediately become zero, and it takes a certain amount of time to converge. Even in such a case, by continuing the first state for a predetermined time by the off-delay means, the interruption of the integration of the integrating means is continued, so that the time until the potential fluctuation due to noise converges is secured, and the integrated value is obtained. It is possible to suppress the occurrence of a large error due to noise. Therefore, it is possible to further suppress the occurrence of false detection due to noise.

In the fourth aspect of the invention, in any one of the first to third aspects, the detection electrode is provided on the back surface of the toilet seat and has a larger area than the heater for heating the toilet seat, and heats the heater. It is a toilet seat device characterized by diffusing into the toilet seat.

According to this toilet seat device, since the area of the detection electrode is large, the seating detection range is widened, and false detection due to the seating position can be suppressed. On the other hand, when the detection electrode is large, the charge / discharge time becomes long because the capacitance of the detection electrode is large, and the time for detecting the capacitance becomes long. Therefore, during the detection of the capacitance, the frequency of overvoltage at the input terminal increases due to noise (for example, noise of the power supply line generated in a short cycle). Even in such a case, by suspending the detection of the capacitance by the capacitance detecting means, it is possible to suppress the occurrence of erroneous detection due to noise. Therefore, it is possible to suppress false detection due to noise while widening the seating detection range.

A fifth aspect of the invention is the second or third aspect, wherein the capacitance detecting means can change the frequency of the switching operation that repeats the first state and the second state to a plurality of frequencies different from each other. When the frequency of the switching operation is changed, the time of one of the first state and the second state is variable, and the time of the other of the first state and the second state is fixed. It is a characteristic toilet seat device.

According to this toilet seat device, by changing the frequency of the switching operation, it is possible to reduce the error caused in the detection result of the capacitance due to the noise of a specific frequency. On the other hand, when the first state and the second state are switched in the switching operation, this switching operation may trigger a phenomenon in which the potential of the detection electrode vibrates. Here, if the frequency of the switching operation is changed, the influence of the vibration of the potential of the detection electrode on the detection result of the capacitance changes, and as a result, there is a possibility that erroneous detection of the presence or absence of the human body occurs. On the other hand, when the frequency of the switching operation is changed, the time of the other of the first state and the second state is fixed, so that the change in the influence of the vibration of the potential of the detection electrode due to the change of the frequency is reduced. be able to. As a result, it is possible to suppress the occurrence of erroneous detection.

A sixth aspect of the invention is the toilet seat device according to the fifth aspect, wherein one is the first state and the other is the second state.

In the first state, the voltage of the detection electrode at the end of the first state affects the detection result of the capacitance detecting means. For example, even if noise is generated in the detection electrode during the first state, there is no substantial effect on the detection result. Therefore, according to this toilet seat device, even if the time of the first state is lengthened and the possibility that noise enters the detection electrode in the middle of the first state increases, it is possible to suppress the decrease in noise immunity.

According to the aspect of the present invention, there is provided a toilet seat device capable of suppressing false detection of the human body due to noise.

FIG. 1 is a perspective view illustrating an toilet device provided with a toilet seat device according to an embodiment. FIG. 2 is a block diagram schematically showing an example of a human body detection sensor included in the toilet seat device according to the embodiment. FIG. 3 is a cross-sectional view schematically showing a part of the toilet seat according to the embodiment. FIG. 4 is a plan view schematically showing the toilet seat according to the embodiment. FIG. 5 is a partial cross-sectional view schematically showing a part of the toilet seat according to the embodiment. FIG. 6 is a block diagram schematically showing the toilet seat device according to the embodiment. 7 (a) to 7 (d) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. 8 (a) to 8 (c) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. FIG. 9 is a schematic block diagram showing a human body detection sensor according to a reference example. 10 (a) to 10 (d) are graphs schematically showing an example of the operation of the detection circuit according to the reference example. 11 (a) to 11 (c) are graphs schematically showing an example of the operation of the detection circuit according to the reference example. FIG. 12 is a block diagram schematically showing a specific example of the human body detection sensor according to the embodiment. 13 (a) to 13 (g) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. 14 (a) to 14 (f) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. It is a block diagram schematically showing another toilet seat device which concerns on embodiment. 16 (a) and 16 (b) are graphs schematically showing the switching operation according to the embodiment. 17 (a) and 17 (b) are graphs schematically showing the switching operation according to the embodiment. 18 (a) and 18 (b) are graphs schematically showing an example of the operation of the detection circuit. 19 (a) and 19 (b) are graphs schematically showing an example of the operation of the detection circuit. 20 (a) and 20 (b) are graphs schematically showing an example of another operation of the detection circuit. 21 (a) and 21 (b) are graphs illustrating the timing at which the discharge time ends.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, similar components are designated by the same reference numerals and detailed description thereof will be omitted as appropriate.
FIG. 1 is a perspective view illustrating an toilet device provided with a toilet seat device according to an embodiment.
As shown in FIG. 1, the toilet device 100 includes a toilet seat device 110 according to an embodiment and a Western-style sitting toilet (hereinafter, simply referred to as "toilet bowl" for convenience of explanation) 104. The toilet seat device 110 is provided on the toilet bowl 104. The toilet seat device 110 includes a main body 112, a toilet seat 114, and a toilet lid 116.

The toilet bowl 104 has a bowl portion 104a that is recessed downward. The toilet bowl 104 receives excrement such as urine and stool of the user in the bowl portion 104a. The main body 112 of the toilet seat device 110 is provided in the upper part behind the bowl portion 104a of the toilet bowl 104. The main body 112 pivotally supports the toilet seat 114 and the toilet lid 116 so as to be openable and closable.

The toilet seat 114 has an opening 114a. The toilet seat 114 is provided on the toilet bowl 104 so as to surround the outer edge of the bowl portion 104a, and exposes the bowl portion 104a through the opening 114a. As a result, the user can excrete in the bowl portion 104a while sitting on the toilet seat 114. In this example, a so-called O-shaped toilet seat 114 in which a through-hole-shaped opening 114a is formed is shown. The toilet seat 114 is not limited to the O-shape, but may be a U-shape or the like.

The toilet seat device 110 has a heating function for warming the seating surface of the toilet seat 114. Further, the toilet seat device 110 has a hygienic cleaning function for cleaning a local part such as a "buttock" of a user sitting on the toilet seat 114. The toilet seat device 110 is, in other words, a sanitary cleaning device. However, the toilet seat device 110 does not necessarily have to have a sanitary cleaning function or a heating function. The toilet seat device 110 may be, for example, a heated toilet seat device having only a heating function.

The toilet seat device 110 has a nozzle 120 for cleaning a local part of the human body. The nozzle 120 is provided in the main body portion 112, and moves back and forth between a position housed in the main body portion 112 and a position advanced from the main body portion 112 into the bowl portion 104a. Note that FIG. 1 shows a state in which the nozzle 120 has advanced into the bowl portion 104a.

The main body 112 is configured to be able to communicate with an operation unit 106 such as a remote controller. The communication between the main body unit 112 and the operation unit 106 may be wired communication or wireless communication. The main body 112 advances the nozzle 120 into the bowl 104a in response to an input of an operation instruction from the operation unit 106, for example.

The nozzle 120 discharges water toward the local part of the human body to clean the local part of the human body. A bidet cleaning spout 120a and a buttocks cleaning spout 120b are provided at the tip of the nozzle 120. The nozzle 120 can inject water from the bidet washing spout 120a provided at the tip thereof to wash a female local part of a woman sitting on the toilet seat 114. Alternatively, the nozzle 120 can inject water from the buttocks washing spout 120b provided at the tip thereof to wash the "buttocks" of the user sitting on the toilet seat 114.

FIG. 2 is a block diagram schematically showing an example of a human body detection sensor included in the toilet seat device according to the embodiment.
The toilet seat device 110 has a human body detection sensor 10. The human body detection sensor 10 includes a detection electrode 12, a detection circuit 14, and a control unit 16.

The human body detection sensor 10 determines the presence or absence of a human body. The human body detection sensor 10 is, for example, a seating detection sensor capable of detecting whether or not the user is seated on the toilet seat 114. The toilet seat device 110 can control the function of the toilet seat device 110 based on the determination result of the presence / absence of the human body (seating) of the human body detection sensor 10. For example, the control unit 16 can control the cleaning function (advance / retreat of the nozzle 120 and stop water discharge of the nozzle 120) and turn on / off the heating function based on the determination result of the human body detection sensor 10.

The capacitance of the detection electrode 12 changes depending on the presence or absence of a human body. For example, the detection electrode 12 is attached to the toilet seat 114, and the capacitance changes according to the sitting of the human body on the toilet seat 114. The detection electrode 12 electrostatically couples with the human body while the human body is seated. As a result, the capacitance of the detection electrode 12 becomes larger in the state where the human body is seated than in the state where the human body is not seated. That is, as shown in FIG. 2, the detection electrode 12 is connected to the common potential GND via, for example, the human body, and forms a capacitance C1 (capacitor) that changes depending on the presence or absence of the human body. The capacitance C1 changes depending on whether the human body is in close proximity (seated) or not (not seated). Therefore, for example, when a pulse signal is transmitted to the detection electrode 12, the current flowing through the detection electrode 12 is larger in the state where the human body is seated than in the state where the human body is not seated. In this example, the human body detection sensor 10 is a so-called self-capacitance type human body detection sensor that detects a change in capacitance due to the presence or absence of a human body with one electrode.

The detection circuit 14 includes a capacitance detecting means 17, an overvoltage detecting means 11, and an off-delay means 19.

The capacitance detecting means 17 has an input terminal 15 electrically connected to the detection electrode 12.
The capacitance detecting means 17 detects a change in the capacitance of the detection electrode 12 by transmitting a signal to the detection electrode 12 via the input terminal 15. For example, the capacitance detecting means 17 transmits a pulse signal of a predetermined number of pulses to the detection electrode 12 via the input terminal 15. Then, the capacitance detecting means 17 detects the charge accumulated in the detection electrode 12 when each pulse is applied to the detection electrode 12 via the input terminal 15, and integrates the charge for each application of each pulse. do. The capacitance detecting means 17 detects a change in the capacitance of the detection electrode 12 based on the integrated value of the electric charge.

The input terminal 15 is not necessarily limited to a connecting member such as a metal fitting, but may be at least a part of a conductor (for example, wiring) that electrically connects the detection electrode 12 and the inside of the capacitance detecting means 17.

The control unit 16 controls the detection of the capacitance by the capacitance detecting means 17. Further, the control unit 16 determines whether or not the human body is seated based on the detection result of the capacitance detecting means 17, that is, the capacitance of the detection electrode 12. In the self-capacitance type sensor, as described above, the capacitance of the detection electrode 12 is larger in the state where the human body is seated than in the state where the human body is not seated. In this case, for example, when the integrated value of the electric charge detected by the capacitance detecting means 17 exceeds the threshold value, the control unit 16 determines that the human body is seated and detects it by the capacitance detecting means 17. When the integrated value of the applied electric charge does not exceed the threshold value, it is determined that the human body is not seated. For the control unit 16, for example, a circuit such as a microcomputer can be used.

The overvoltage detecting means 11 is electrically connected to the input terminal 15 of the capacitance detecting means 17. The voltage of the input terminal 15 is input to the overvoltage detecting means 11. As a result, the overvoltage detecting means 11 detects the overvoltage at the input terminal 15. In other words, the overvoltage detecting means 11 detects whether or not the voltage of the input terminal 15 has reached a predetermined voltage. Further, the overvoltage detecting means 11 is electrically connected to the capacitance detecting means 17 via the off-delay means 19.

When the overvoltage is detected by the overvoltage detecting means 11, a signal corresponding to the detection of the overvoltage is input to the capacitance detecting means 17 via the off-delay means 19. Then, the capacitance detecting means 17 suspends the detection of the capacitance of the detection electrode 12, and then restarts the detection of the capacitance of the detection electrode 12.

For example, the detection circuit 14 may generate electrical noise. Overvoltage may occur at the input terminal 15 due to noise. As will be described later, as such noise, for example, noise generated in the power supply line of the human body detection sensor 10 is assumed. However, the noise in the embodiment is not necessarily limited to the noise from the power supply line. When noise (overvoltage) is generated in the input terminal 15 and a current caused by the noise flows from the input terminal 15 to the capacitance detecting means 17, a large error occurs in the detection result (that is, the integrated value) of the capacitance detecting means 17. May occur. Therefore, noise may cause erroneous detection of the human body. That is, the overvoltage means an excessive voltage that causes a false detection of the human body, and the voltage fluctuation on the minus side as well as the plus side becomes an overvoltage. If a specific numerical value is given, the overvoltage detecting means 11 detects any of plus 50V or more and minus 50V or less as an overvoltage.

On the other hand, in the detection circuit 14, as described above, when the overvoltage detecting means 11 detects the overvoltage, the capacitance detecting means 17 suspends the detection of the capacitance and then restarts. As a result, even when an overvoltage is generated in the input terminal due to noise such as a power supply, the capacitance detecting means suspends the detection of the capacitance, so that it is possible to suppress the occurrence of erroneous detection due to the noise.

In the detection of the capacitance of the detection electrode 12, the charge accumulated in the capacitance C1 is input to the charge amount measuring unit (for example, an integrating means described later) of the capacitance detecting means 17 via the input terminal 15. Will be done. For example, as will be described later, the capacitance detecting means 17 is provided with a switch. By turning the switch on and off periodically, the transmission of the pulse signal to the detection electrode 12 and the integration of the electric charge for each application of each pulse are periodically repeated. In this case, pausing the detection of the capacitance of the detection electrode 12 corresponds to, for example, pausing the periodic on / off of the switch. Further, resuming the detection of the capacitance of the detection electrode 12 corresponds to resuming the on / off of the switch periodically.

The off-delay means 19 is electrically connected to the overvoltage detecting means 11 and the capacitance detecting means 17. The off-delay means 19 is a circuit for causing the capacitance detecting means 17 to continue the state in which the detection of the capacitance is suspended for a predetermined time. When the off-delay means 19 receives the signal corresponding to the detection of the overvoltage from the overvoltage detecting means 11, the off-delay means 19 transmits the signal to the capacitance detecting means 17. The capacitance detecting means 17 continues the state in which the detection of the capacitance is temporarily stopped for a predetermined time in response to the signal from the off-delaying means 19. The output of the off-delay means 19 can adjust the length of time that the capacitance detection is paused.

For example, the noise generated in the detection circuit 14 may continue the noise generated in the input terminal 15. Even in such a case, the off-delay means 19 can suppress the influence of noise on the detection result of the capacitance detecting means 17 by continuing the state in which the detection of the capacitance is paused. The off-delay means 19 may not always be provided in the embodiment.

Hereinafter, specific examples of the toilet seat device 110 and the human body detection sensor 10 will be described by exemplifying a case where the detection electrode 12 is a heat diffusion sheet for diffusing the heat of the heater provided on the toilet seat.

FIG. 3 is a cross-sectional view schematically showing a part of the toilet seat according to the embodiment.
FIG. 3 schematically shows a cross section taken along the line A1-A2 of FIG.
As shown in FIG. 3, the toilet seat 114 has an internal space SP. In other words, the toilet seat 114 is hollow. The toilet seat 114 has, for example, an upper plate 130 and a lower plate 132, and by joining the upper plate 130 and the lower plate 132, an internal space SP is formed between the upper plate 130 and the lower plate 132. The upper plate 130 has a seating surface 130a on which the user sits, and an inner surface 130b facing the lower plate 132. In other words, the inner surface 130b is a surface (the back surface of the toilet seat 114) facing the seating surface 130a in the internal space SP. The upper plate 130 and the lower plate 132 may be bonded by using an adhesive or by welding using vibration welding or the like. However, the configuration of the toilet seat 114 is not limited to the above, and may be any configuration having at least an internal space SP, a seating surface 130a, and an inner surface 130b.

FIG. 4 is a plan view schematically showing the toilet seat according to the embodiment.
FIG. 5 is a partial cross-sectional view schematically showing a part of the toilet seat according to the embodiment.
As shown in FIGS. 4 and 5, the heater 204 is provided in the internal space SP and heats the seating surface 130a from the inside via the inner surface 130b by applying an AC voltage from the outside. The heater 204 generates heat by passing an electric current. The heater 204 is, for example, a heating wire.

The detection electrode 12 is provided on the inner surface 130b. The detection electrode 12 is, for example, in the shape of a sheet. The heater 204 is, for example, in the shape of a cord. The area of the detection electrode 12 is larger than the area of the heater 204. As a result, the detection electrode 12 diffuses the heat of the heater 204 to the inner surface 130b. As described above, the detection electrode 12 is provided on the inner surface 130b, has a larger area than the heater 204, has an area larger than that of the heater 204, and has a larger capacitance depending on whether or not the toilet seat 114 is seated. Diffuse on the surface 130b. That is, the detection electrode 12 functions as an electrode for detecting the presence or absence of seating on the toilet seat 114, and also functions as a heat diffusion sheet for diffusing the heat of the heater 204 to the inner surface 130b.

A first adhesive 240 is provided between the detection electrode 12 and the heater 204. The first adhesive 240 joins the detection electrode 12 and the heater 204.

A second adhesive 242 is provided between the detection electrode 12 and the inner surface 130b of the upper plate 130. The second adhesive 242 joins the detection electrode 12 and the inner surface 130b of the upper plate 130. As a result, the detection electrode 12 is provided on the inner surface 130b of the upper plate 130.

The detection electrode 12 is a conductor. The detection electrode 12 is, for example, a metal foil. The thermal conductivity of the metal foil is higher than the thermal conductivity of the upper plate 130, which is generally made of resin. Examples of the detection electrode 12 include aluminum foil and copper foil.

As shown in FIG. 4, the heater 204 meanders at the detection electrode 12 and is arranged over substantially the entire circumference (entire circumference) of the detection electrode 12. Further, the detection electrode 12 is provided over substantially the entire (entire circumference) of the inner surface 130b of the upper plate 130. The heater 204 meanders under the inner surface 130b of the upper plate 130 and is disposed over substantially the entire inner surface 130b. In this way, the cord-shaped heater 204 is provided on the inner surface 130b while bending. The heater 204 is not limited to the cord shape, but may be a sheet shape or the like. The configuration of the heater 204 may be any configuration capable of heating the seating surface 130a from the inside.

FIG. 6 is a block diagram schematically showing the toilet seat device according to the embodiment.
As shown in FIG. 6, the toilet seat device 110 has a power supply circuit 18 (switching power supply circuit). The power supply circuit 18 is electrically connected to the AC power supply PS via the coil 38 and the power supply terminal 30. The power supply circuit 18 converts the AC power supplied from the AC power supply PS into DC power, and supplies the converted DC power to the detection circuit 14 and the control unit 16. The detection circuit 14 and the control unit 16 operate based on the supply of DC power from the power supply circuit 18. The AC power supply PS is, for example, a commercial power supply of AC100V (effective value). The power supply terminal 30 is, for example, an outlet plug. The power supply circuit 18 is, for example, an isolated AC / DC converter. A varistor 60 is provided between the grounded side 30a and the non-grounded side 30b of the power supply terminal 30. A varistor 61 is provided between the ground side 30a of the power supply terminal 30 and the common potential GND.

The power supply circuit 18 includes, for example, a rectifier circuit 31, a smoothing capacitor 32, and a conversion circuit 33. The rectifier circuit 31 rectifies the AC voltage supplied from the AC power supply PS and converts it into the rectified voltage of the pulsating current. The rectifier circuit 31 is, for example, a full-wave rectifier using a diode bridge, and converts an AC voltage into a full-wave rectified rectifier voltage. The rectifier circuit 31 may be, for example, a half-wave rectifier.

The smoothing capacitor 32 smoothes the rectified voltage rectified by the rectifier circuit 31 and converts the rectified voltage into a DC voltage.

The conversion circuit 33 converts the DC voltage converted by the smoothing capacitor 32 into the DC power corresponding to the detection circuit 14 and the control unit 16. The conversion circuit 33 is a so-called DC-DC converter. The conversion circuit 33 converts, for example, a DC voltage of 100V into a DC voltage of about 5V to 24V. In other words, the conversion circuit 33 is a buck converter. The conversion circuit 33 supplies the converted DC power to the detection circuit 14 and the control unit 16. As a result, the detection circuit 14 and the control unit 16 can operate in response to the supply of DC power from the conversion circuit 33 (power supply circuit 18).

The conversion circuit 33 has a transformer 34 that electrically insulates the primary side (AC power supply PS side) and the secondary side (load side). In other words, the conversion circuit 33 electrically insulates the input side and the output side. The conversion circuit 33 is, for example, an isolated converter. The conversion circuit 33 is, for example, a flyback converter. However, the conversion circuit 33 does not necessarily have to be an isolated converter. The configuration of the power supply circuit 18 may be any configuration capable of converting AC power into DC power according to the detection circuit 14 and the control unit 16.

The coil 38 is, for example, a common mode choke coil for suppressing common mode noise. The end 38a of the coil 38 is electrically connected to one input terminal of the rectifier circuit 31. The end 38b of the coil 38 is electrically connected to the other input terminal of the rectifier circuit 31. Further, the end portion 38c of the coil 38 is connected to the common potential GND via the varistor 61. Further, the end portion 38d of the coil 38 is electrically connected to the non-grounded side 30b of the power supply terminal 30. The common potential GND is, for example, the potential of the earth (so-called earth). The common potential GND may be, for example, the potential of the conductive frame or chassis of the device (so-called frame ground or chassis ground).

The power supply circuit 18 further includes a capacitor 37. The capacitor 37 is provided between the common potential GND on the primary side and the common potential GND on the secondary side of the conversion circuit 33. The capacitor 37 suppresses noise on the GND on the secondary side by the voltage conversion operation of the conversion circuit 33.

The toilet seat device 110 has a heater 204 that heats the toilet seat 114. The heater 204 is connected to the power supply terminal 30. As a result, the AC voltage supplied from the AC power supply PS is applied to the heater 204. Further, a switching element 220 for switching between the application of the AC voltage to the heater 204 and the stop of the application is provided between the heater 204 and the power supply terminal 30. For the switching element 220, for example, a phototriac can be used. The switching element 220 is connected to the control unit 16. The control unit 16 controls switching on / off of the switching element 220. In other words, the control unit 16 controls energization (application of AC voltage and stop of application) to the heater 204.

The control unit 16 controls the energization of the heater 204 so that, for example, the temperature of the seating surface 130a of the toilet seat 114 becomes a predetermined set temperature set by the operation of the operation unit 106 or the like. Further, for example, when the seating is not detected by the detection circuit 14, the control unit 16 lowers the temperature of the seating surface 130a of the toilet seat 114 below the set temperature. Then, when the seating is detected by the detection circuit 14, the control unit 16 raises the temperature of the seating surface 130a of the toilet seat 114 to a set temperature. As a result, unnecessary power consumption can be suppressed when not in use, and power consumption of the toilet seat device 110 can be suppressed.

The control unit 16 controls the energization of the heater 204 by, for example, a pattern control method in which a plurality of half waves of an AC voltage are used as one unit. The control unit 16 switches the energization of the heater 204 and the stop of the energization according to the detection result of the zero cross point, for example. The control unit 202 increases the number of half-waves to be energized when, for example, raises the temperature of the seating surface 130a, and increases the number of half-waves to be energized when keeping or lowering the temperature of the seating surface 130a. reduce. Thereby, the temperature of the seating surface 130a can be controlled to a desired temperature.

In this example, the heat diffusion sheet described with respect to FIGS. 4 and 5 is used for the detection electrode 12. The capacitance C1 is formed by the heat diffusion sheet (detection electrode 12) provided on the toilet seat 114 and the human body HB. The capacitance detecting means 17 detects the capacitance C1.

The capacitance detecting means 17 includes, for example, a switch unit 20, a charge amount measuring unit 22, a protection resistor 42, and a varistor 44. The switch unit 20 functions as, for example, a pulse output unit. That is, the switch unit 20 transmits a pulse signal to the detection electrode 12 based on the input from the control unit 16. The charge amount measuring unit 22 measures the capacitance of the detection electrode 12 based on the charge amount of the detection electrode 12 when the pulse signal is transmitted from the switch unit 20 to the detection electrode 12. The measured capacitance is input to the control unit 16. For example, the integrated value of the electric charge is input to the control unit 16 as the capacitance of the detection electrode 12.

The switch unit 20 includes a first switch 71, a second switch 72, an inverter circuit 73, and an OR circuit 74. One of the input sides of the OR circuit 74 is connected to the control unit 16. The output side of the OR circuit is connected to the first switch 71 and is also connected to the second switch 72 via the inverter circuit 73. One end of the first switch 71 is connected to a predetermined voltage (power supply voltage VCS), and the other end of the first switch 71 is connected to one end of the second switch 72. The other end of the second switch 72 is connected to the charge amount measuring unit 22 (integrating means 52).

The charge amount measuring unit 22 includes an integrating means 52 (capacitor), a transistor 54, a resistance 55, and a resistance 56. One end of the integrating means 52 is connected to the second switch 72, and the other end of the integrating means 52 is connected to the common potential GND on the secondary side. The base of the transistor 54 is connected to the control unit 16 via the resistor 55, and is also connected to the common potential GND on the secondary side via the resistor 56. The emitter of the transistor 54 is connected to the common potential GND on the secondary side. The collector of the transistor 54 is connected to the control unit 16 and is connected between the second switch 72 and the integrating means 52.

One end of the protection resistor 42 is connected between the first switch 71 and the second switch 72. The other end of the protection resistor 42 is connected to the input terminal 15. In other words, the first switch 71 and the second switch 72 are electrically connected to the input terminal 15 via the protection resistor 42. For the first switch 71 and the second switch 72, for example, an analog switch or the like can be used. However, the first switch 71 and the second switch 72 are not limited to this, and any configuration capable of switching between conduction and non-conduction can be used. The protection resistor 42 is a component that protects the capacitance detecting means 17 composed of electronic components from external electrical stress. The varistor 44 is connected between the common potential GND on the secondary side and the input terminal 15, and protects the capacitance detecting means 17 from component destruction due to overvoltage or the like.
A specific example of the overvoltage detecting means 11 and the off-delaying means 19 will be described later with reference to FIG.

Next, with reference to FIGS. 7 and 8, an example of the operation of the capacitance detecting means 17 when no noise is generated, that is, when an overvoltage is not generated at the input terminal 15 will be described.

7 (a) to 7 (d) and 8 (a) to 8 (c) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. In these figures, the vertical axis represents a signal (voltage) and the horizontal axis represents time. 8 (a), 8 (b), and 8 (c) are enlarged portions of FIGS. 7 (b), 7 (c), and 7 (d), respectively.

As shown in FIG. 7A, when detecting the seating of the human body HB, the control unit 16 first inputs a Hi signal to the base side of the transistor 54. That is, the signal S3 on the base side of the transistor 54 is set to Hi. As a result, the transistor 54 is turned on, the integrating means 52 is discharged, and the signal S2 of the integrating means 52 is reset to the common potential GND on the secondary side as shown in FIG. 7D.

After that, as shown in FIG. 7B, the control unit 16 periodically and alternately inputs the Hi signal and the Lo signal to the switch unit 20. That is, the signals S1 on the input side of the switch unit 20 are periodically and alternately set to Hi and Lo. When the overvoltage of the input terminal 15 is not detected, the output signal S6 of the OR circuit 74 is Hi when the signal S1 is Hi, and Lo when the signal S1 is Lo.

The first switch 71 and the second switch 72 are turned on when a Hi signal is input and turned off when a Lo signal is input, respectively. That is, the first switch 71 is turned on when the signal S1 is Hi, and is turned off when the signal S1 is Lo. On the contrary, the second switch 72 is turned off when the signal S1 is Hi, and turned on when the signal S1 is Lo. In this way, the capacitance detecting means 17 has a first state in which the first switch 71 is on and the second switch 72 is off, and a first state in which the first switch 71 is off, in response to an input from the control unit 16. A switching operation is executed in which the second state in which the two switches 72 are turned on and the second state are periodically alternately repeated.

In the first state, the detection electrode 12 conducts with the power supply voltage VCS via the input terminal 15, the protection resistor 42, and the first switch 71. As a result, electric charges are accumulated in the capacitance C1 of the detection electrode 12. As described above, the first state is a state in which electric charges are accumulated in the capacitance C1 of the detection electrode 12. 7 (c) and 8 (b) are the signal S100 of the input terminal 15 and correspond to the potential of the detection electrode 12. For example, as shown in FIG. 8B, immediately before the times T1, T3, T5, and T7, the signal S100 has a predetermined voltage (power supply voltage VCS in this example). In other words, the first state is a state in which the capacitance C1 of the detection electrode 12 is charged to a predetermined voltage.

On the other hand, in the second state, the detection electrode 12 conducts with the integrating means 52 via the input terminal 15, the protection resistor 42, and the second switch 72. As a result, the electric charge accumulated in the capacitance C1 is input to the integrating means 52. As described above, the second state is a state in which the electric charge accumulated in the capacitance C1 of the detection electrode 12 is output to the integrating means 52. Therefore, for example, as shown in FIG. 8B, the signal S100 drops from a predetermined potential between time T1 and time T2, between time T3 and time T4, and between time T5 and time T6. ing. In other words, the second state is a state in which the capacitance C1 of the detection electrode 12 is discharged.

In this way, by the switching operation of switching between the first state and the second state of the switch unit 20 at a predetermined frequency, a pulse signal corresponding to the predetermined voltage is input to the detection electrode 12 and accumulated in the capacitance C1. The charged charge is input to the integrating means 52. The frequency of the pulse signal can be changed according to the frequency of the signal S1. Further, the signal S100 has a blunt waveform as compared with the signal S1 due to the delay due to the CR circuit such as the capacitance C1 and the protection resistor 42.

The integrating means 52 stores the electric charge discharged from the capacitance C1 of the detection electrode 12 in the second state repeated by the switching operation. Therefore, for example, as shown in FIG. 8C, the signal S2, which is the output of the integrating means 52, increases in proportion to the number of switchings between the first state and the second state, that is, the “number of integrations”. For example, as in the signal levels at times T1, T3, and T5, the signal S2 increases by a predetermined value each time the capacitance detecting means 17 enters the second state.

Random noise called white noise is generated in the electric circuit, but as the number of integrations increases, the random noise is averaged and the output of the integration circuit 50 becomes stable. That is, as the number of integrations increases, the amount of signals increases and noise decreases, so that the detection circuit 14 operates at a high S / N.

In this way, the integrating means 52 integrates the electric charge of the capacitance C1 input at a predetermined frequency according to the switching operation, and outputs the integrated value as a detection result to the control unit 16. The control unit 16 A / D-converts the integrated value and determines whether or not the human body HB is seated. The capacitance C1 with the human body HB (the state in which the human body is close to the detection electrode 12) is larger than the capacitance C1 in the state without the human body HB (the state in which the human body is not close to the detection electrode 12). growing. Therefore, when switching between the first state and the second state is performed a predetermined number of times in a predetermined cycle and the electric charge of the capacitance C1 is integrated as described above, the integrated value (change amount) in the state where the human body HB is present is. , It becomes larger than the integral value in the state without the human body HB.

The control unit 16 determines whether or not the human body HB is seated according to the electric charge (result of A / D conversion of the integrated value) accumulated in the integrating means 52. More specifically, for example, the control unit 16 switches between the first state and the second state using the signal S2 (in this example, the common potential GND on the secondary side) after resetting the integrating means 52 as a reference value. The amount of change from the reference value of the signal S2 after the above is performed a predetermined number of times is treated as an integrated value (capacitance detection result). The control unit 16 determines whether or not the human body HB is seated based on this integrated value. The number of times (the number of pulses) of switching between the first state and the second state is, for example, about 1000 times.

The capacitance detecting means 17 repeatedly executes the operations shown in FIGS. 7 (a) to 7 (d) at a predetermined cycle. As a result, the control unit 16 repeatedly determines whether or not the human body HB is seated at a predetermined cycle, and as a result, the seating detection can be continuously performed.

Next, an example of noise and false positives will be described.
The inventor of the present application has found that in a conventional capacitive seating sensor, if the area of the detection electrode is increased, the influence of noise becomes large, and there is a possibility that false detection of the seating state is more likely to occur.

As described above, there is a method of using a heat diffusion sheet having a larger area than the heater as the detection electrode 12. The heat diffusion sheet thermally strongly bonds with the heater in the toilet seat. The heat diffusion sheet has a role of spreading the heat generated by the heater substantially evenly over the entire toilet seat. Therefore, the heat diffusion sheet is widely provided in the portion of the toilet seat where the user may be seated. Therefore, if the heat diffusion sheet is used as the detection electrode, it is possible to prevent the user from missing the seat depending on the place where the user sits. Further, since it is not necessary to provide a detection electrode separately from the heat diffusion sheet, it is preferable to use the heat diffusion sheet as the detection electrode.

However, since the heat diffusion sheet is thermally strongly bonded to the heater, the electrostatic bond between the heat diffusion sheet and the heater is also strong. Therefore, noise may enter from the heater to the heat diffusion sheet, that is, from the heater to the detection electrode. Examples of this noise include noise from a commercial power source directly connected to the heater.

Further, the area of the heat diffusion sheet is as large as the seating area of the toilet seat, for example. Since the area of the heat diffusion sheet is large, the detection capacity is large. According to the experiment of the inventor of the present application, for example, the coupling capacity between the heater and the heat diffusion sheet is about 300 pF, which is constantly detected even when not seated. Further, when the user sits down, about 100 pF is added to the detection capacity depending on the human body, and the total detection capacity is about 400 pF. However, this is a case where the user simply sits on the toilet seat, and if the user puts his foot on the floor with bare feet or touches the surrounding metal with his hands, the electrical between the human body and the ground is electrical. The binding is strengthened and the detection capacity is further increased. Therefore, the capacitance detection circuit may be required to have a performance capable of detecting a capacitance of a maximum of several hundred pF.

Further, the measurement time is limited in the electrostatic detection of a large capacity. An example will be described. First, the detection capacity is large because the area of the detection electrode is large, and as a result, external noise is likely to enter the detection electrode. Therefore, as an input protection means of the capacitance detection circuit, it is conceivable to attach a protection resistor in series with the detection electrode. Further, there are several methods for capacitance detection, and as described above, there is a method of applying an AC pulse to the detection electrode and measuring the amount of charge flowing out or flowing in at that time. For example, if the area of the detection electrode is large and the detection capacitance is large, and a protection resistor is attached to the detection electrode, the time constant determined by multiplying the detection capacitance and the protection resistance becomes large. For example, the pulse width of the above-mentioned AC pulse is set to a sufficient time in consideration of this time constant.

As a trial calculation, if the detection capacitance is 400 pF and the protection resistance is 10 kΩ, the time constant is 4 μs. Considering the CR transient phenomenon, for example, charging and discharging can be performed up to about 99% of the final value at 5 times the time constant. Therefore, if the Hi / Lo time of the AC pulse is 20 μs, the cycle of the AC pulse is 40 μs and the frequency. Is 25 kHz. Further, it is conceivable to improve the accuracy of the capacitance measurement by repeating the output of the AC pulse and the measurement of the coulometric load. For example, if 1000 AC pulses are output for one capacitance measurement, the measurement time is 40 μs × 1000 times = 40 ms.

As a general capacitance sensor, for example, a sensor that detects a touch operation with a fingertip can be mentioned. In this case, since the detection capacity is, for example, about 1 pF, the measurement time is 0.1 ms if calculated with the same idea. As described above, in the capacitance type seating sensor using the heat diffusion sheet of the toilet seat as the detection electrode, the measurement time may be an order of magnitude longer than that of a general capacitance sensor.

The above-mentioned example of "noise from commercial power supply" is given. There is "phase control" as a typical method of power control. This controls the thyristor of the switch element from off to on and from on to off at an arbitrary phase with respect to the waveform of the AC power supply to conduct the load for an arbitrary time. This control is performed every half wave of the AC power supply. At this time, there is a steep current fluctuation, and a high-frequency short-time click noise is generated in the power supply line. That is, the noise at the time of turning on the thyristor is superimposed on each half wave of the power supply waveform. If the frequency of the commercial power supply is 50 Hz, noise is generated every 10 ms.

Since the measurement time of the above-mentioned capacitance is 40 ms, if a device for performing phase control is connected to the same power supply line, noise will be input a plurality of times during one measurement. The noise voltage may be as high as 1 kV, for example, and if such a voltage enters the capacitance detection circuit during measurement, the measurement result may fluctuate greatly and the seated state may be erroneously detected.

For example, as a means for suppressing such false detection, a capacitor equivalent to the above-mentioned "capacitance sensor that detects the touch operation of the fingertip" is attached to a part of the toilet seat and seated in a narrow range of the fingertip. A method of detection is also conceivable. In this case, since the detection capacitance is as small as, for example, about 1 pF, the measurement time is shortened, and sitting detection can be performed while avoiding noise generated in a cycle of about 10 ms. For example, it is possible to finish the capacitance detection in the time between one noise and the next. However, since the detection area is small, the detection range is limited to a narrow part. Therefore, erroneous detection may occur depending on the seating position of the user.

Further, as another means for suppressing erroneous detection, if noise is detected during measurement, a method of discarding one measurement data at that time can be considered. However, when the measurement time is long or noise occurs in a short cycle, the noise is frequently generated in one measurement time, so most of the measurement data is discarded, and seating detection is performed. I can't do it.

As described above, in a toilet seat having a heat diffusion sheet, if the heat diffusion sheet of the toilet seat is used as a detection electrode, the seating detection range can be widened without providing a new detection electrode, and an error due to the seating position can be obtained. Detection can be suppressed. On the other hand, when the detection area (electrode) is increased, the detection capacity is increased, the charge / discharge time to the detection electrode is lengthened, and the measurement time is lengthened. The longer the measurement time, the greater the effect of noise on the measurement results. For example, it becomes difficult to avoid the influence of power supply noise generated in a short cycle (for example, noise generated at a frequency twice the power supply frequency by phase control). Therefore, it is desired to suppress false detection due to noise while increasing the seating detection area of the toilet seat.

For example, as shown by the arrow AR1 shown in FIG. 6, noise is transmitted from the power supply terminal 30 to the input terminal 15 via the capacitance C2 between the heater 204 and the detection electrode 12. Further, as shown by the arrow AR2 shown in FIG. 6, the noise is transmitted from the input terminal 15 to the common potential GND on the secondary side via the capacitance detecting means 17, and passes through the capacitor 37 of the power supply circuit 18. It is transmitted to the common potential GND on the primary side, and escapes to the potential of the earth via the coil 38. For example, there is a capacitor 37 and a coil 38 on the path from the detection electrode 12 to the ground of the noise that has entered, which may affect the seating detection.

An example of the influence of noise on seating detection will be described with reference to FIGS. 9, 10 (a) to 10 (d) and FIGS. 11 (a) to 11 (c).
FIG. 9 is a schematic block diagram showing a toilet seat device according to a reference example.
FIG. 9 shows a human body detection sensor 910 provided in the toilet seat device of the reference example. The human body detection sensor 910 of the reference example is not provided with the overvoltage detecting means and the off-delay means. Further, the OR circuit 74 is not provided either. Other than this, the configuration of the toilet seat device of the reference example is the same as that of the toilet seat device described with respect to FIG. 6 and the like. Also in the reference example, the heat diffusion sheet of the heater is used for the detection electrode.

10 (a) to 10 (d) and 11 (a) to 11 (c) are graphs schematically showing an example of the operation of the detection circuit according to the reference example. These figures show the case where an overvoltage occurs in the input terminal in the seating detection by the human body detection sensor 910 shown in FIG. In these figures, the vertical axis represents a signal (voltage) and the horizontal axis represents time. 11 (a), 11 (b), and 11 (c) are enlarged portions of FIGS. 10 (b), 10 (c), and 10 (d), respectively.

As shown in FIG. 10 (b), a pulse signal is transmitted to the detection capacitance by alternately turning the two switches on and off. Along with this, charging and discharging of the detection capacitance are repeated as shown in the waveform of the input terminal shown in FIG. 10 (c), and the output potential of the integrating means rises as shown in FIG. 10 (d).

Noise may occur during the integration operation, and the voltage of the input terminal may fluctuate significantly as shown in FIG. 10 (c). For example, in a state where the input terminal is conducting to the integrating means via the protection resistor and the second switch (second state) as between the time T15 and the time T17 shown in FIG. 11 (b). Noise that vibrates greatly is generated in the voltage of the input terminal. If the capacitance detecting means is in the second state when an overvoltage (noise) is generated at the input terminal, the electric charge caused by the noise is accumulated in the integrating means, and the electric charge is the detection result (integrated value). It will be an error. Therefore, there is a risk of false detection of the human body.

For example, the peak value of instantaneous noise (for example, one pulse at time T16 in FIG. 11B) is about 1 kV, and the pulse width is about 1 μs. The peak value can be suppressed to a certain voltage by the varistor of the input terminal. Still, depending on the selection of the varistor, the peak value may be several tens of volts or more. Momentary noise enters the heat diffusion sheet from the heater through capacitive coupling. That is, since the noise at the input terminal becomes an AC signal via the capacitor, the noise can be either positive or negative.

The energy of the momentary noise escapes to the ground through the circuit of the toilet seat device. At that time, the voltage of the input terminal vibrates due to the capacitance component of the capacitor of the power supply circuit of the toilet seat device and the induction component of the coil. For example, when the waveform is observed in detail, such as between the time T16 and the time T17 in FIG. 11B, after a momentary noise is introduced, the secondary side with the detection circuit fluctuates with a time delay. Since the secondary circuit has a coupling between the ground and the resistance component due to a load (not shown) such as a valve or a nozzle, the vibration is attenuated and disappears. Depending on the state of the toilet seat device, the time is, for example, about several μs to several tens of μs. This time is longer than the time when momentary noise is applied (for example, about 1 μs). Therefore, even if the noise voltage is relatively suppressed by the varistor connected to the input terminal, the error in the detection result (integral value) vibrates as shown in FIGS. 10 (d) and 11 (c). It increases to correspond to the product of voltage and time.

As described above, even if the noise is momentary, if the noise voltage is large, the error of the integrated value becomes large. Further, even if the noise voltage is not extremely large, if the time until the voltage decays is long, the integrated error becomes large.

On the other hand, in the embodiment, as described above, the overvoltage detecting means 11 is provided. When the overvoltage detecting means 11 detects the overvoltage, the capacitance detecting means 17 suspends the detection of the capacitance and then restarts it. As a result, it is possible to suppress erroneous detection due to noise while increasing the seating detection area of the toilet seat. An example of the overvoltage detecting means 11, the off-delay means 19, and the detection operation will be described with reference to FIGS. 12, 13 (a) to 13 (g) and FIGS. 14 (a) to 14 (f).

FIG. 12 is a block diagram schematically showing a specific example of the human body detection sensor according to the embodiment.
The detection circuit 14 shown in FIG. 12 is an example of the detection circuit 14 of the human body detection sensor 10 described with respect to FIG. As shown in FIG. 12, the overvoltage detecting means 11 includes diodes 80 and 89, Zener diodes 81 and 82, transistors 83 and 84, and resistors 85, 86, 87 and 88.

The anode side of the diode 80 is electrically connected to the input terminal 15, and the cathode side of the diode 80 is electrically connected to the cathode side of the Zener diode 81. The anode side of the Zener diode 81 is electrically connected to the base of the transistor 84 via a resistor 87. In the transistor 84, the emitter is connected to the common potential GND on the secondary side, and a resistor 88 is connected between the emitter and the base. The collector of the transistor 84 is electrically connected to the off-delay means 19.

The cathode side of the diode 89 is electrically connected to the input terminal 15, and the anode side of the diode 89 is electrically connected to the anode side of the Zener diode 82. The cathode side of the Zener diode 82 is electrically connected to the base of the transistor 83 via the resistor 86. In the transistor 83, the emitter is connected to the power supply voltage VCS, and a resistor 85 is connected between the emitter and the base. The collector of the transistor 83 is electrically connected to the base of the transistor 84 via the resistor 87.

The off-delay means 19 has a resistance 91, a capacitor 93, and an inverter circuit 95. One end of the resistor 91 is electrically connected to the power supply voltage VCS, and the other end of the resistor 91 is connected to the common potential GND on the secondary side via the capacitor 93. The collector of the transistor 84 is electrically connected between the resistor 91 and the capacitor 93. As a result, the output signal of the overvoltage detecting means 11 is input between the resistor 91 and the capacitor 93. The input side of the inverter circuit 95 is electrically connected between the resistor 91 and the capacitor 93, and the output side of the inverter circuit 95 is electrically connected to the input side of the OR circuit 74.

For example, the Zener voltage Vz1 of the Zener diode 81 and the Zener voltage Vz2 of the Zener diode 82 are selected to have values smaller than the protection voltage Vp of the varistor 44, respectively. In the embodiment, the varistor 44 and the protection resistor 42 do not necessarily have to be provided, but are provided as needed.

13 (a) to 13 (g) and 14 (a) to 14 (f) are graphs schematically showing an example of the operation of the detection circuit according to the embodiment. These figures show the case where an overvoltage (noise) occurs in the input terminal 15 in the seating detection by the human body detection sensor 10 shown in FIG. In these figures, the vertical axis represents a signal (voltage) and the horizontal axis represents time. 14 (a), 14 (b), 14 (c), 14 (d), 14 (e), and 14 (f) are shown in FIGS. 13 (b) and 13 (c), respectively. , FIG. 13 (d), FIG. 13 (e), FIG. 13 (f), and FIG. 13 (g) are shown in an enlarged manner.

As shown in FIG. 13A, when detecting the seating of the human body HB, the control unit 16 first sets the signal S3 on the base side of the transistor 54 to Hi. As a result, the signal of the integrating means 52 is reset. After that, as shown in FIG. 13B, a switching operation is performed in which the first state and the second state are periodically and alternately repeated. Then, charging and discharging of the capacitance C1 are repeated alternately, and the waveform of the input terminal 15 vibrates as shown in FIG. 13 (c). Along with this, the electric charge discharged from the capacitance C1 is integrated into the integrating means, and as shown in FIG. 13 (g), the change from the reference value of the signal S2 becomes large.

In such an integration operation, as shown in FIG. 13 (c), the voltage of the input terminal may fluctuate greatly. For example, as shown in FIG. 14 (b), at time T26, momentary noise enters the input terminal 15. Then, the noise of the input terminal 15 is attenuated while vibrating, such as between the time T26 and the time T27.

For example, when a positive overvoltage occurs in the input terminal 15, the signal S4 on the base side of the transistor 84 changes from Lo to Hi, as shown in FIGS. 13 (d) and 14 (c). For example, a pulse is generated in the signal S4. In this way, the overvoltage detecting means 11 detects the overvoltage of the input terminal 15. The overvoltage detection in the overvoltage detecting means 11 operates when the overvoltage exceeds the Zener voltage of the Zener diode. More specifically, in the case of a positive overvoltage, the overvoltage is detected when the voltage of the input terminal 15 exceeds a predetermined value (Vf1 + Vz1 + Vbe1). Here, Vf1 is the forward voltage of the diode 80, Vz1 is the Zener voltage of the Zener diode 81, and Vbe1 is the voltage between the base and emitter of the transistor 84. In the case of a negative overvoltage, the overvoltage is detected when the voltage of the input terminal 15 falls below a predetermined value (VCC-Vbe2-Vz2-Vf2). Here, VCS is the power supply voltage, Vbe2 is the voltage between the base and emitter of the transistor 83, Vz2 is the Zener voltage of the Zener diode 82, and Vf2 is the forward voltage of the diode 89. The predetermined value (overvoltage) detected by the overvoltage detecting means 11 may be appropriately set so as to suppress erroneous detection in consideration of the magnitude of the error given to the detection result by noise.

When a positive or negative overvoltage is detected by the overvoltage detecting means 11, the capacitor 93 of the off-delay means 19 is discharged. As a result, the voltage on the input side of the inverter circuit 95 fluctuates, and as shown in FIGS. 13 (e) and 14 (d), the signal S5 on the output side of the inverter circuit 95 changes from Lo to Hi. For example, a pulse is generated in the signal S5. The width of this pulse corresponds to the CR time constant due to the capacitor 93 and the resistor 91.

The output of the off-delay means 19, that is, the signal S5 is input to the OR circuit 74. Therefore, when the signal S5 is Hi, the output (signal S6) of the OR circuit 74 becomes Hi regardless of the input from the control unit 16 (signal S1). As a result, the capacitance detecting means 17 is in the first state in which the first switch 71 is on and the second switch 72 is off. In other words, when the overvoltage is detected, the capacitance detecting means 17 is forcibly put into the first state.

This first state continues while the signal S5 is Hi. In the first state, since the second switch 72 is off, the charge is not integrated into the integrating means 52, and the noise at the input terminal 15 is not integrated. Therefore, for example, as shown in FIG. 14 (f), the signal S2 does not change between the time T26 and the time T27.

Further, since the first switch 71 is on, the input terminal 15 is connected to the power supply voltage VCS, so that noise easily escapes to a power supply having a low impedance. That is, in order not to integrate noise, it is sufficient to forcibly turn off the second switch 72 when an overvoltage is detected, and when such control is performed, the first switch 71 and the second switch 72 may be turned off. A state in which both are turned off (so to speak, a third state) can occur, but in the first state, the noise is more likely to be attenuated faster because the first switch 71 is on than in the case where both are turned off.

After that, when the signal S5 changes from Hi to Lo again, the output of the OR circuit 74 (signal S6) periodically repeats Hi and Lo again in response to the signal S1. That is, the capacitance detecting means 17 restarts the switching operation based on the input from the control unit 16.

As described above, in the embodiment, the integration operation is paused at the moment when noise enters the input terminal 15 and for a predetermined time immediately after that. This predetermined time can be adjusted, for example, by the pulse width of the signal S5. As shown in FIGS. 14 (c) and 14 (d), the pulse of the signal S5 is longer than the pulse of the signal S4. For example, the pulse width of the signal S5 is determined so that the signal S5 becomes Hi until the noise of the input terminal 15 is attenuated while vibrating and becomes smaller after the time T26 in FIG. 14B. For example, the pulse width of the signal S5 is 10 μs or more and 100 μs or less.

Even when the noise is damped and vibrated due to the capacitance component or the inductive component of the power supply circuit, the off-delay means 19 can wait for the restart of the integration operation until the noise becomes small. For example, by pausing the switching operation, the duration of the first state becomes longer than the duration of the periodic first state by the switching operation. That is, for example, in the example of FIG. 14 (e), the duration of the first state from the time T26 to the time T28 is longer than the duration of the first state from the time T24 to the time T25. In the embodiment, since the integration is interrupted at the moment when the noise enters and the voltage fluctuation thereafter, it is possible to suppress the noise from being integrated and causing a large error.

At this time, depending on the timing of the noise and the signal S1, the original signal (charge of the capacitance C1) cannot be integrated. In that case, the integrated value for one switching operation (the amount of change in the signal S2 due to one charge / discharge of the capacitance C1) becomes an error, but for example, 1000 switching operations with one measured capacitance. If integrated with, the effect is only 0.1%. In the human body detection sensor according to the reference example of FIG. 9, the error due to noise may be several percent. Therefore, by interrupting the integration operation and not integrating the noise as in the embodiment, it is possible to suppress the occurrence of a large error. can do. Therefore, it is possible to suppress the occurrence of false detection of the human body due to noise.

As described above, in the embodiment, when the overvoltage detecting means 11 detects the overvoltage in the input terminal 15, the capacitance detecting means 17 temporarily stops the switching operation in which the first state and the second state are alternately repeated. Then, the first switch 71 and the second switch 72 are set to the first state. After that, the capacitance detecting means 17 restarts the switching operation.
According to such a configuration, when an overvoltage occurs in the input terminal 15 due to noise such as a power supply, the capacitance detecting means 17 suspends the switching operation and enters the first state, whereby the integrating means Since the integration (accumulation of electric charge) of is interrupted, it is possible to suppress the occurrence of a large error in the integrated value due to noise. Therefore, it is possible to suppress the occurrence of false detection due to noise.

Further, the off-delay means 19 causes the capacitance detecting means 17 to continue the first state for a predetermined time when the overvoltage detecting means 11 detects the overvoltage.
According to such a configuration, by continuing the first state, the interruption of the integration of the integrating means is continued, so that it is possible to further suppress the occurrence of erroneous detection due to noise.
For example, the application of an overvoltage (noise) may cause a potential fluctuation in the reference voltage (secondary GND) of the circuit of the toilet seat device. At this time, for example, the circuit of the toilet seat device may contain a capacitance component or an inductive component, so that the state in which the potential fluctuation occurs in the input terminal may continue. This potential fluctuation may cause a large error in capacitance detection. That is, since the circuit of the toilet seat device has a capacitance component and an inductive component, even if the applied overvoltage is momentary, the potential fluctuation due to noise does not immediately become zero, and it takes a certain amount of time to converge. On the other hand, according to the embodiment, by continuing the first state for a predetermined time by the off-delay means, the interruption of the integration of the integrating means is continued, so that the time until the potential fluctuation due to noise converges is secured. Therefore, it is possible to suppress the occurrence of a large error due to noise in the integrated value. Therefore, it is possible to further suppress the occurrence of false detection due to noise.

Further, as described above, when the heat diffusion sheet is used for the detection electrode 12, the large area of the detection electrode 12 widens the seating detection range and can suppress erroneous detection due to the seating position. On the other hand, when the detection electrode 12 is large, the charge / discharge time becomes long because the capacitance of the detection electrode 12 is large, and the time for detecting the capacitance becomes long. Therefore, during the detection of the capacitance, the frequency of overvoltage occurring in the input terminal 15 increases due to noise (for example, noise of the power supply line generated in a short cycle). Even in such a case, by suspending the detection of the capacitance by the capacitance detecting means 17, it is possible to suppress the occurrence of erroneous detection due to noise. Therefore, it is possible to suppress false detection due to noise while widening the seating detection range.

The noise detected by the overvoltage detecting means in the embodiment is not necessarily limited to the noise from the power supply as described above, and may be any noise that causes an overvoltage at the input terminal 15.

Further, the detection electrode 12 is not limited to the heat diffusion sheet of the heater 204, and may be provided separately from the heat diffusion sheet. The heat diffusion sheet is, for example, a metal anchor arranged over substantially the entire inner surface 130b of the toilet seat 114, and diffuses the heat of the heater 204 to the inner surface 130b. Also in this case, for example, the detection electrode 12 can be arranged on the inner surface 130b of the toilet seat 114. For example, the detection electrode 12 may be stacked on the heat diffusion sheet or under the heat diffusion sheet. In either arrangement, the heat diffusion sheet, which is a metal, electrostatically couples with the human body and also electrostatically couples with the detection electrode 12, so the electrostatic capacity with the human body is measured from the detection electrode 12 via the heat diffusion sheet. It becomes possible. Alternatively, the electrostatic influence of the heat diffusion sheet may be removed by cutting out only the portion of the heat diffusion sheet that overlaps with the detection electrode 12. In this case, the area of the detection electrode 12 may be smaller than the area of the heat diffusion sheet 250. Further, the arrangement of the detection electrode 12 does not necessarily have to be the inner surface 130b. The detection electrode 12 may be arranged at any position capable of appropriately detecting the human body seated on the toilet seat 114.

Further, the human body detection sensor according to the embodiment is not limited to the self-capacity type as described above, and may be a mutual capacity type. In the mutual capacitance type capacitive sensor, the detection electrode has a transmission electrode and a reception electrode. The detection circuit is electrically connected to the transmitting electrode and the receiving electrode. Since the electric field around the detection electrode changes depending on the presence or absence of the human body, the amount of received charge of the receiving electrode when a pulse signal having a predetermined frequency is transmitted to the transmitting electrode changes. The detection circuit measures the amount of received charge of the receiving electrode as the capacitance of the detecting electrode. The presence or absence of a human body can be determined by the change in capacitance.

FIG. 15 is a block diagram schematically showing another toilet seat device according to the embodiment.
The toilet seat device 111 shown in FIG. 15 has a detection circuit 14b instead of the detection circuit 14 described above. As will be described later, the toilet seat device 111 is different from the above-mentioned toilet seat device 110 in the switching operation by the capacitance detecting means 17b of the detection circuit 14b and the operation of the control unit 16. Other than this, the same description as that of the toilet seat device 110 can be applied to the description of the configuration of the toilet seat device 111.

The detection circuit 14b is not provided with the overvoltage detecting means 11 and the off-delay means 19. Further, the detection circuit 14b has a capacitance detecting means 17b instead of the capacitance detecting means 17. The capacitance detecting means 17b is not provided with the OR circuit 74 as compared with the capacitance detecting means 17. In the capacitance detecting means 17b, the signal S1 becomes an input signal of the switch 71 and the inverter circuit 73. Other than this, the same description as that of the detection circuit 14 can be applied to the description of the configuration of the detection circuit 14b.

That is, the toilet seat device 111 includes a toilet seat 114, a detection electrode 12, a capacitance detecting means 17b, and a control unit 16. The capacitance C1 of the detection electrode 12 changes according to the sitting of the human body on the toilet seat 114. The capacitance detecting means 17b is electrically connected to the detection electrode 12, and detects a change in the capacitance C1 of the detection electrode 12. The control unit 16 determines whether or not the human body is seated based on the detection result (integral value) of the capacitance detecting means. Similarly to the detection circuit 14, the detection circuit 14b may be provided with the overvoltage detection means 11, the off-delay means 19, and the OR circuit 74, and the capacitance detection may be paused or restarted.

The capacitance detecting means 17b includes a first switch 71, a second switch 72, and an integrating means 52. As described above, the first and second switches 71 and 72 are analog switches including elements such as transistors and the like. The first switch 71 connects a predetermined voltage (power supply voltage VCS) to the detection electrode 12. When the first switch 71 is turned on, the predetermined voltage and the detection electrode 12 are electrically connected, and when the first switch 71 is turned off, the predetermined voltage and the detection electrode 12 are non-conducting. The second switch 72 connects the integrating means 52 and the detection electrode 12. By turning on the second switch 72, the integrating means 52 and the detection electrode 12 become conductive, by turning off the second switch 72, the integrating means 52 and the detection electrode 12 become non-conducting.

The capacitance detecting means 17b detects a change in the capacitance C1 of the detection electrode 12 by a switching operation. The switching operation is an operation in which the first state (charging) and the second state (discharging) are alternately repeated at a predetermined frequency, and a pulse signal having a predetermined frequency is transmitted to the detection electrode 12. As described above, in the first state, the first switch 71 is on and the second switch 72 is off. In the first state, a pulse signal is transmitted to the detection electrode 12, the detection electrode 12 is set to a predetermined voltage, and the detection capacitance (capacitance C1 and capacitance C2) is charged. In the second state, the first switch 71 is off and the second switch 72 is on. The second state discharges the detection capacity of. The integrating means 52 stores the electric charge discharged from the detection electrode 12.

The capacitance detecting means 17b can change the frequency of the switching operation that repeats the first state and the second state to a plurality of frequencies different from each other. In other words, the capacitance detecting means 17b can transmit a plurality of pulse signals having different frequencies to the detection electrode 12. The frequency of the switching operation, that is, the frequency of the pulse signal is the frequency of the signal S1 and is controlled by the control unit 16.

For example, the capacitance detecting means 17b can switch the frequency of the switching operation between the first frequency and the second frequency different from the first frequency. In other words, the switching operation includes a first switching operation of the first frequency and a second switching operation of the second frequency. In the first switching operation, the first state and the second state are repeated at the first frequency by the signal S1 of the first frequency, and the pulse signal is transmitted at the first frequency. In the first switching operation, the first state and the second state are repeated a predetermined number of times at the first frequency, that is, a predetermined number of pulse signals are transmitted at the first frequency, and a change in the capacitance C1 is detected. Similarly, in the second switching operation, the first state and the second state are repeated a predetermined number of times at the second frequency, that is, a predetermined number of pulse signals are transmitted at the second frequency, and a change in the capacitance C1 is detected. Even if the frequencies of the signals S1 are different, the charges stored in the integrating means 52 are the same as long as the predetermined number of repetitions is the same. That is, even if the frequency of the signal S1 is changed, there is no effect on the detection result of the capacitance in principle.

For example, the capacitance detecting means 17b changes the frequency of the switching operation at a predetermined timing or a random timing. For example, the capacitance detecting means 17b may alternately repeat the first switching operation and the second switching operation. However, not limited to this, the frequency of the switching operation can be changed at an appropriate timing. Further, the frequency of the switching operation is not limited to the two frequencies of the first frequency and the second frequency, but may be three or more.

16 (a), 16 (b), 17 (a), and 17 (b) are graphs schematically showing the switching operation according to the embodiment.
In these figures, the vertical axis represents a signal (voltage) and the horizontal axis represents time. 16 (a) and 16 (b) illustrate the first switching operation of the first frequency by the capacitance detecting means 17b. 17 (a) and 17 (b) illustrate the second switching operation of the second frequency by the capacitance detecting means 17b.

16 (a) shows the signal S1 of the first frequency, and FIG. 16 (b) shows the signal S100 when the signal S1 changes as shown in FIG. 16 (a). Similarly, FIG. 17 (a) represents the signal S1 of the second frequency, and FIG. 17 (b) represents the signal S100 when the signal S1 changes as shown in FIG. 17 (a). When the signal S1 is Hi, the capacitance detecting means 17b is in the first state (charging), and when the signal S1 is Lo, the capacitance detecting means 17b is in the second state (discharging).

In FIGS. 16 (b) and 17 (b), the solid line waveform is the waveform when the damped vibration described later occurs, and the dotted waveform is the waveform when it is assumed that there is no damped vibration. That is, the dotted line waveform is a waveform obtained by removing the influence of the damping vibration described later from the solid line waveform, and corresponds to, for example, an ideal waveform in design. In addition, in the explanation and graph (for example, FIG. 8B, FIG. 11B, FIG. 14B, etc.) regarding the toilet seat device 110 according to the above-described embodiment and the toilet seat device according to the reference example, for convenience of explanation. , This damped vibration is omitted.

As shown in FIG. 16A, for example, at time T31, the capacitance detecting means 17b switches from the second state to the first state. Then, the first state continues from the time T31 to the time T32. At time T32, the capacitance detecting means 17b switches from the first state to the second state. Then, the second state continues from the time T32 to the time T33. In the first switching operation, the same operation as from time T31 to time T33 is periodically repeated.

As shown in FIG. 17A, for example, at time T41, the capacitance detecting means 17b switches from the second state to the first state. Then, the first state continues from the time T41 to the time T42. At time T42, the capacitance detecting means 17b switches from the first state to the second state. Then, the second state continues from the time T42 to the time T43. In the second switching operation, the same operation as from time T41 to time T43 is periodically repeated.

As mentioned above, the first frequency and the second frequency are different from each other. That is, the cycle P1 of the first switching operation (for example, from time T31 to time T33) is different from the cycle P2 of the second switching operation (for example, from time T41 to time T43). The period P2 is longer than the period P1.

When the frequency of the switching operation is changed, the capacitance detecting means 17b makes the time of one of the first state and the second state variable, and fixes the time of the other of the first state and the second state. That is, the duration of one of the first state and the second state (hereinafter sometimes referred to as "variable side") in the first switching operation is different from the duration of the variable side in the second switching operation, and the first switching The duration of the other of the first state and the second state (hereinafter sometimes referred to as "fixed side") in the operation is the same as the duration of the fixed side in the second switching operation.

For example, in this example, the time of the first state (charging) is variable and the time of the second state (discharging) is fixed. More specifically, the duration P11 (for example, from time T31 to time T32) of the first state in the first switching operation shown in FIG. 16A is the second switching operation shown in FIG. 17A. It is shorter than the duration P21 of the first state (for example, from time T41 to time T42). On the other hand, the duration P12 (for example, from time T32 to time T33) of the second state in the first switching operation shown in FIG. 16A is the second state in the second switching operation shown in FIG. 17A. It is the same as the duration P22 (for example, from time T42 to time T43).

In the embodiment, when the frequency of the switching operation is changed, the time of the first state may be fixed and the time of the second state may be variable. Further, "fixing" the time means not only that the time does not change exactly, but also that the time may change slightly within a range of variation (for example, variation due to a change in the characteristics of the elements constituting the circuit with time).

By changing the frequency of the switching operation, it is possible to reduce the error caused in the detection result of the capacitance due to the noise of a specific frequency. On the other hand, for example, as shown in FIGS. 16B and 17B, when the first state and the second state are switched in the switching operation, the potential of the detection electrode may vibrate. For example, as will be described later, the circuit through which the current for charging / discharging the detection capacitance flows in the first state and the second state includes LCRs (inductors, capacitors and resistors) connected in series with each other. Therefore, when the first state and the second state are switched, the potential of the detection electrode 12 may be damped and vibrated according to the LCR. This damped vibration is similarly generated in both the first state and the second state. Here, if the frequency of the switching operation is changed, the influence of the vibration of the potential of the detection electrode on the detection result of the capacitance changes, and as a result, there is a possibility that erroneous detection of the presence or absence of the human body occurs. On the other hand, when the frequency of the switching operation is changed, the time of the other of the first state and the second state is fixed, so that the change in the influence of the vibration of the potential of the detection electrode due to the change of the frequency is reduced. be able to. As a result, it is possible to suppress the occurrence of erroneous detection. This will be described below with reference to specific examples.

The detection electrode 12 is affected by noise existing in the measurement environment. Common noise is called white noise, which is random noise containing many frequency components. If the charge / discharge operation, that is, the integration operation is repeated at a constant frequency, the timing of the random noise and the integration operation varies and is not limited to a specific pattern. The effect of noise is virtually zero (if the number of integrations is high).

However, noise may have a specific frequency. For example, there are devices such as switching power supplies, motors, and wireless devices that emit noise of a specific frequency depending on the operation. When the noise frequency and the charge / discharge frequency are synchronized, that is, when there is an integer ratio relationship, the influence of noise on the charge / discharge operation becomes the same condition every time, and the influence of noise is accumulated by repeating charging / discharging, and the detection result. A large error is given to (integrated value), and capacity detection becomes false detection.

In such a case, it is conceivable to change the charge / discharge frequency (frequency of the switching operation) so that the charge / discharge operation is not synchronized with the noise. The conditions for changing the charge / discharge frequency are the method of randomly changing the charge / discharge frequency in the normal measurement stage (frequency burst) and the measurement at different charge / discharge frequencies when the seating / non-seating judgment changes. There are methods such as checking the result.

On the other hand, in this example, the charge / discharge operation of the capacitance detection circuit is performed by the path DL represented by the broken line in FIG. The capacitance detecting means 17b is on the secondary side, and the detection electrode 12 is electrostatically coupled to the heater 204, that is, before the human body is seated, there is already a large capacitance C2 in the non-seat state, and the capacitance is electrostatic. The capacitance detecting means 17b charges and discharges the capacitance C2. Since charging / discharging is an electrical operation, it forms a closed circuit. From the capacitance detecting means 17b, the detection electrode 12, the heater 204, the power supply line 30a (including 30b when the switching element 220 is on), and the line filter. The path returning to the secondary GND via the coil 38 and the capacitor 37 between the primary and secondary is the charge / discharge circuit.

In this closed circuit, electrical elements such as a protection resistor 42, a coupling capacitance (capacitance C2) between the detection electrode 12 and the heater 204, a coil 38, and a primary-secondary capacitor 37 are connected in series. Here, since the capacitor 37 between the primary and secondary is sufficiently large (for example, 10 times or more) as compared with the capacitance C2, the capacitance (series capacitance) of the charge / discharge path is set to the capacitance C2. Almost equal. That is, the capacitor 37 between the primary and secondary may be regarded as a short circuit and excluded. Then, R of the protection resistance 42, C of the coupling capacitance (capacitance C2), and L of the line filter (coil 38) are connected in series to form a circuit in which damping vibration of LCR series resonance is generated. In the charge / discharge operation, the power supply voltage is alternately output to the detection electrode 12 during charging and the integrated voltage is output at the time of discharging. Therefore, due to the potential change, the LCR is applied to the closed circuit of the charging / discharging operation. Attenuation vibration of resonance occurs. Then, this vibration becomes an error factor of the integrated value of the capacitance detecting means.

As described above, the circuit for passing a current through the detection electrode 12 when charging / discharging includes an LCR series circuit. That is, the circuit through which the current for charging the detection capacity in the first state and the current discharged from the detection capacity in the second state flows includes an inductor, a capacitor, and a resistor connected in series with each other. Therefore, switching from the first state to the second state or switching from the second state to the first state may cause damped vibration in the potential of the detection electrode 12.

In the embodiment, the charge / discharge path of the detection electrode 12 is not necessarily limited to the example of FIG. The LCR connected to the charge / discharge path does not necessarily have to be the coil 38 of the line filter, the coupling capacitance (capacitance C2) of the detection electrode 12, and the protection resistance 42. Further, the toilet seat device may have not only a toilet seat heating function but also a hygienic cleaning function, and an element of an electrical load (motor or the like) for that purpose may be added as a new LCR component. Therefore, the charge / discharge path of the detection electrode 12 includes the resistance component, the induction component, and the capacitance component of the entire toilet seat device, and the potential of the detection electrode 12 is damped and vibrated at least during charging and discharging. ..

A specific example in which such potential vibration causes an error will be described.
In the detection of capacitance, the detection electrode 12 is charged with a constant voltage V, and a charge (Q = C × V) proportional to the capacitance C2 of the detection electrode 12 is accumulated, which is discharged and integrated. By doing so, it is converted into an electric signal. Therefore, for example, if the portion of the charging voltage V is not constant, the principle does not hold, and the fluctuation of the charging voltage V may cause a detection error of the capacitance detecting means. Since the damped vibration of the LCR changes the V portion of Q = C × V, it causes a detection error of the capacitance both during charging and discharging.

18 (a) and 18 (b) are graphs schematically showing an example of the operation of the detection circuit.
18 (a) and 18 (b) are waveforms when damping vibration due to LCR occurs in the waveforms shown in FIGS. 8 (a) and 8 (b), and is a diagram in which the time axis is further enlarged. be. That is, the waveform at the time of charging / discharging may actually be such a waveform.

As shown in FIG. 18A, at time T51, the capacitance detecting means switches from the second state to the first state. The first state continues from time T51 to time T52. At time T52, the capacitance detecting means switches from the first state to the second state. The second state continues from time T52 to time T53.

In FIG. 18B, when the voltage at the end of charging (for example, time T52) deviates from the original charging voltage (power supply voltage VCS) due to damped vibration, this voltage difference ΔV becomes an error factor. In the case of FIG. 18B, since the charge end voltage is lower than the power supply voltage VCS, the charge voltage of the detection electrode 12 becomes low, the charge to be charged decreases, the charge integrated at the time of discharge also decreases, and the electrostatic capacity The detection result becomes smaller. That is, the vibration component at the end of charging becomes a detection error.

Similarly, the vibration component is integrated during discharge. This is affected by the area IS (voltage difference with respect to the ideal waveform x time) during integration. If the sum of the area IS is not zero with respect to the ideal waveform in design, an error will occur. As described above, the vibration component during integration is the detection error from the ideal value (when there is no vibration). The ideal waveform and ideal value are waveforms and voltage values when there is no damped vibration due to LCR. The area IS is an integrated value obtained by integrating the difference between the waveform (broken line) when there is no damped vibration and the waveform (solid line) when there is damped vibration over time. The area IS becomes an error factor during the integration at the time of discharge. That is, the integrated value of the vibration component during the discharge period becomes the detection error.

The seating sensor (control unit 16) is seated when the capacitance C2 between the detection electrode 12 and the heater 204 is added to the capacitance C1 between the detection electrode 12 and the human body HB and the integrated value changes. Determined to be present. That is, it suffices if it can be determined that the detection capacity increases relatively based on the capacitance C2. Therefore, even if there is a detection error, if it is constant, it will affect the seating detection (seating determination). It can be suppressed. In the first place, for the purpose of detecting the sitting of the human body, the capacitance C2 itself is a fixed detection error.

Therefore, if the charge / discharge time is fixed, the influence of the damped vibration due to the LCR is fixed, and by treating this as a fixed offset component of the detection capacity, the seating determination can be performed.

If the charge / discharge time is constant, the influence of the damped vibration due to the LCR can be fixed, but in order to avoid the influence of the noise of the specific frequency described above, the charge / discharge time, that is, the charge / discharge frequency may be changed. Then, the influence of the damped vibration due to the LCR changes, a difference occurs in the detection result of the capacitance, and there is a possibility that the seated state is erroneously detected.

19 (a) and 19 (b) are graphs schematically showing an example of the operation of the detection circuit.
19 (a) and 19 (b) show the case where the charge / discharge time is shortened in FIGS. 18 (a) and 18 (b). That is, FIGS. 19 (a) and 19 (b) show a case where the charge / discharge frequency (frequency of switching operation) is increased for the purpose of noise countermeasures, for example.

As shown in FIG. 19A, at time T54, the capacitance detecting means switches from the second state to the first state. The first state continues from time T54 to time T55. At time T55, the capacitance detecting means switches from the first state to the second state. The second state continues from time T55 to time T56.

In the examples of FIGS. 18 and 19, both the time of the first state (charging time) and the time of the second state (discharge time) are variable when the charge / discharge frequency changes. That is, the charging time (time T54 to time T55) in FIG. 19A is shorter than the charging time (time T51 to time T52) in FIG. 18A. Further, the discharge time (time T55 to time T56) in FIG. 19 (a) is shorter than the discharge time (time T52 to time T53) in FIG. 18 (a).

As shown in FIG. 19B, since charging / discharging is switched in the middle of the damped vibration by the LCR, the voltage at the end of charging and the integrated amount during discharging change depending on the timing. That is, the voltage difference ΔV at the end of charging in FIG. 19 (b) is different from the voltage difference ΔV at the end of charging in FIG. 18 (b), and the total area IS during discharge in FIG. 19 (b) is FIG. It is different from the total area IS during discharge in (b). Therefore, the detection result of the capacitance is different only by changing the charge / discharge frequency. As a result, there is a risk of false detection of the seated state.

Therefore, since it is the damped vibration that has an effect, a method of waiting for the damped vibration to converge before performing the charge / discharge operation is also conceivable.
20 (a) and 20 (b) are graphs schematically showing an example of another operation of the detection circuit.
20 (a) and 20 (b) show the case where the charge / discharge time is lengthened in FIGS. 18 (a) and 18 (b).

As shown in FIG. 20A, at time T57, the capacitance detecting means switches from the second state to the first state. The first state continues from time T57 to time T58. At time T58, the capacitance detecting means switches from the first state to the second state. The second state continues from time T58 to time T59.

The charging time (from time T57 to time T58) in FIG. 20A is longer than the charging time in FIG. 18A. Therefore, the voltage difference ΔV at the end of charging in FIG. 20B is smaller than the voltage difference ΔV at the end of charging in FIG. 18B. For example, the voltage difference ΔV at the end of charging in FIG. 20B is sufficiently attenuated in vibration and can be regarded as substantially zero.
Further, the discharge time (from time T58 to time T59) in FIG. 20 (a) is longer than the discharge time in FIG. 18 (a). Therefore, the vibration is sufficiently attenuated at the timing when the discharge time ends (time T59), and the total area IS during discharge in FIG. 20 (b) is not easily affected by the discharge time and is stable. On the other hand, the total area IS during discharge in FIG. 18B is easily affected by the integration time and is not stable. Therefore, for example, the total area IS during discharge in FIG. 20B can be regarded as a substantially fixed value, so that the error can be regarded as zero.

In this way, by lengthening the charge / discharge time and converging the damped vibration, it is possible to suppress an error due to the damped vibration. However, in this example, in order to change the charge / discharge frequency, the charge / discharge time is further lengthened. In this case, the detection time becomes long, and the seating determination may be delayed.

On the other hand, in the embodiment, as described above with respect to FIGS. 16A and 17A, when the charge / discharge frequency is changed, one of the charge time and the discharge time is variable and the other is fixed. .. In other words, when changing the frequency of the switching operation, the time of one of the first state and the second state is variable, and the time of the other of the first state and the second state is fixed. As a result, the operation affected by the change in the damped vibration is only one of charging and discharging, so that the influence of the damped vibration can be reduced. Therefore, it is possible to further suppress the occurrence of false detection of the human body.

Further, in the embodiment, as shown in FIGS. 16A and 17A, the variable side of the first state and the second state is fixed in the first state and the second state. Longer than the side to do. For example, in FIGS. 16A and 17A, the time on the variable side is equal to or longer than the time during which the vibration of the potential of the detection electrode 12 when switching between the first state and the second state is attenuated. On the other hand, the time on the fixing side is shorter than the time during which the vibration of the potential of the detection electrode 12 when switching between the first state and the second state is attenuated. The time during which the vibration of the potential of the detection electrode is damped is, for example, two cycles or more, preferably three cycles or more, of the damped vibration when the capacitance detecting means 17b switches from the fixed side to the variable side. ..

By making the time on the variable side longer than the damping time of the vibration, it is possible to reduce the influence of the vibration of the potential of the detection electrode 12 on the variable side on the detection result of the capacitance. Therefore, it is possible to reduce the change in the influence of the vibration of the potential of the detection electrode 12 due to the change of the charge / discharge frequency. For example, in FIGS. 16 (b) and 17 (b), the charging time is long, the vibration is almost converged at the end of charging (for example, time T32 and time T42), and the charging voltage is stable. The voltage difference ΔV is sufficiently small at the end of charging. As described above, if the vibration component at the end of charging is attenuated, the error is small even if the charging time is changed.

On the other hand, since the time on the fixing side is relatively short, the vibration of the potential of the detection electrode 12 on the fixing side is not attenuated, which affects the detection result of the capacitance. However, since the time on the fixed side is fixed, the influence of the vibration of the potential of the detection electrode 12 does not change due to the change in frequency and becomes a constant value. For example, in FIGS. 16 (b) and 17 (b), since the discharge time is short and fixed, the integrated value is stable. The integrated value (area IS) of the vibration component during the discharge period becomes an error in the detection result of the capacitance, but since the discharge time is fixed, the change of the integrated value (area IS) is suppressed. .. Therefore, even if there is an error in the detection result of the capacitance, the error component is kept constant regardless of the charge / discharge frequency, so that the influence on the seating determination result can be suppressed.

Further, by shortening the time on the fixing side, it is possible to suppress the lengthening of the time of one cycle and the lengthening of the entire detection time. Even if the charging time is lengthened, the overall charging / discharging time can be made relatively short, so that it is possible to suppress the slow response of the seating sensor.

Further, as already described, in the examples of FIGS. 16A and 17A, the fixed side is the first state and the variable side is the second state. In other words, the time on the variable side is the charging time, and the time on the fixed side is the discharging time.

In the charging operation (first state), the voltage at the end of charging (final voltage applied to the capacitance) is proportional to the charge charged to the capacitance, so the voltage at the end of charging is the capacitance. Affects the detection result of. Therefore, for example, even if noise is received during charging, the detection result of the capacitance is not substantially affected. Therefore, even if the charging time is lengthened and the possibility of noise entering the detection electrode during charging increases, the noise immunity does not decrease.
On the other hand, in the discharge operation (second state), the charge charged in the detection electrode 12 is discharged and integrated. Therefore, if noise is introduced during the discharge operation, the noise is also input to the integrating means and integrated. Therefore, the noise remains as an error of the integrated voltage, and the detection result of the electrostatic charge changes. Therefore, the longer the discharge time, the lower the noise immunity.
For the above reasons, when the charge / discharge time is the same (the reaction time for seating detection is the same), the noise immunity is improved by selecting a longer charging time and a shorter discharging time. In FIGS. 16 (a) and 17 (a), since the discharge time is shorter than the charge time, it is difficult for noise to enter the discharge time.

21 (a) and 21 (b) are graphs illustrating the timing at which the discharge time ends.
21 (a) and 21 (b) show waveforms at the time of charging / discharging as in FIGS. 18 (a) and 18 (b). As shown in FIG. 21 (a), the capacitance detecting means is in the first state from time T61 to T62. The capacitance detecting means switches from the first state to the second state at time T62. The waveform shown in FIG. 21B is a waveform when the user is not seated on the toilet seat and is not seated. Further, in order to explain the waveform of the damped vibration, the waveform in which the second state continues is shown for convenience, not the waveform in which the second state is switched to the first state again after the time T62.

It is desirable that the time of the second state is 1/4 of the period Pd of the damped vibration of the potential of the detection electrode when the first state and the second state are switched in the non-seating state. That is, as shown in FIG. 21 (a), it is desirable that the capacitance detecting means switches from the second state to the first state at the time T63 one-fourth period after the time T62.

Since the resonance frequency of the LCR is determined by L and C, it changes depending on the fluctuation between L and C. Since there are individual variations and temperature changes in both L and C, and the operating frequency of the control unit (for example, microcomputer) that generates the charge / discharge time also varies, even if the discharge time is fixed control, the integration result includes variations. , It is impossible to completely avoid the influence of vibration, and conditions that are more stable against the influence of vibration are preferable.

The timing of 1/4 of the vibration cycle Pd is a flat part where the voltage waveform of the detection electrode 12 changes from falling to rising, and even if there is a change in the resonance frequency, compared to the part where the vibration waveform has a large inclination. , The effect can be kept small. The timing of 1/2 cycle and 1 cycle is compared with the timing of 1/4 cycle because the slope of vibration is large, so it is easily affected by changes in vibration conditions, and the detection result of capacitance tends to be unstable. Not suitable. At the timing of 1/4 of the vibration cycle Pd, the vibration waveform is flat and is not easily affected by changes in vibration conditions.

There is also a flat part in the 3/4 cycle part, but the vibration waveform is the part that changes from rising to falling, and the LC resonance circuit has the energy on the side that lowers the voltage of the detection electrode 12. be. Here, when switching from discharging to charging, the voltage of the detection electrode 12 changes on the rising side, so that the polarities of the two are opposite to each other. Therefore, in the timing of 3/4 cycle, it may not be possible to smoothly shift to charging as compared with the timing of 1/4 cycle. The timing of the 1/4 cycle is the opposite of the above, and since both the LC resonance and the charging operation are the operations on the side where the potential of the detection electrode 12 is raised, the charging can be smoothly performed.

However, in the embodiment, the time of the second state (timing of the end of discharge) is not necessarily limited to 1/4 of the period Pd, and may be any timing. Further, the time of the second state being 1/4 of the period Pd is not only strictly 1/4, but may include, for example, a range of variation of the elements constituting the circuit.

The embodiment of the present invention has been described above. However, the present invention is not limited to these descriptions. The above-mentioned embodiments which have been appropriately designed by those skilled in the art are also included in the scope of the present invention as long as they have the features of the present invention. For example, the shape, size, material, arrangement, installation form, and the like of each element included in the toilet seat device are not limited to those exemplified, and can be appropriately changed.
Further, the elements included in each of the above-described embodiments can be combined as much as technically possible, and the combination thereof is also included in the scope of the present invention as long as the features of the present invention are included.

10 Human body detection sensor, 11 Overvoltage detection means, 12 Detection electrode, 14, 14b detection circuit, 15 Input terminal, 16 Control unit, 17, 17b Capacitor detection means, 18 Power supply circuit, 19 Off-delay means, 20 Switch part, 22 Charge amount measuring unit, 30 power supply terminal, 31 rectifying circuit, 32 smoothing capacitor, 33 conversion circuit, 34 transformer, 37 capacitor, 38 coil, 42 protection resistor, 44 varistor, 50 integrator circuit, 52 integrator, 54 transistor, 55 , 56 resistors, 60, 61 varistor, 71 1st switch, 72 2nd switch, 73 inverter circuit, 74 OR circuit, 80 capacitors, 81, 82 Zener diodes, 83, 84 transistors, 85-88 resistors, 89 capacitors, 91 Resistance, 93 Capacitor, 95 Inverter circuit, 100 Toilet device, 104 Toilet bowl, 104a Bowl part, 106 Operation part, 110, 111 Toilet seat device, 112 Main body part, 114 Toilet seat, 114a opening, 116 Toilet lid, 120 nozzle, 120a bidet Cleaning spout, 120b tail cleaning spout, 130 upper plate, 130a seating surface, 130b inner surface, 132 lower plate, 202 control unit, 204 heater, 220 switching element, 240, 242 first, second adhesive, 250 heat Diffusion sheet, 910 human body detection sensor, ΔV voltage difference, C1, C2 capacitance, DL path, HB human body, IS area, P1, P2 cycle, P11, P12, P21, P22 duration, Pd cycle, PS AC power supply, S1 to S6, S100 signal, SP internal space, T31 to T33, T41 to T43, T51 to T59, T61 to T63 Time, VCS power supply voltage

Claims (6)

Toilet seat and
A detection electrode whose capacitance changes according to the sitting of the human body on the toilet seat,
Capacitance detecting means having an input terminal electrically connected to the detection electrode and detecting the capacitance of the detection electrode,
A control unit that determines whether or not the human body is seated based on the detection result of the capacitance detecting means.
An overvoltage detecting means for detecting an overvoltage at the input terminal,
Equipped with
A toilet seat device, characterized in that, when the overvoltage detecting means detects the overvoltage, the capacitance detecting means pauses and then restarts the detection of the capacitance. The capacitance detecting means is
An integrating means for storing the electric charge discharged from the detection electrode and
The first switch connected to the specified voltage,
A second switch connected to the input terminal and the integrating means,
The first state in which the first switch is on and the second switch is off to charge the detection electrode to the predetermined voltage, and the first switch is off and the second switch is on. Yes A switching operation that alternately repeats the second state of discharging the detection electrode is executed.
The integrating means stores the electric charge discharged from the detection electrode in the second state repeated by the switching operation.
The control unit determines whether or not the human body is seated according to the electric charge accumulated in the integrating means.
When the overvoltage detecting means detects the overvoltage, the capacitance detecting means suspends the switching operation, puts the first switch and the second switch into the first state, and then performs the switching operation. The toilet seat device according to claim 1, wherein the toilet seat device is restarted. The toilet seat device according to claim 2, further comprising an off-delay means for continuing the first state for a predetermined time when the overvoltage detecting means detects the overvoltage. One of claims 1 to 3, wherein the detection electrode is provided on the back surface of the toilet seat, has a larger area than a heater for heating the toilet seat, and diffuses the heat of the heater to the toilet seat. The toilet seat device described in 1. The capacitance detecting means can change the frequency of the switching operation that repeats the first state and the second state to a plurality of frequencies different from each other, and when changing the frequency of the switching operation, the said. The toilet seat device according to claim 2 or 3, wherein the time of one of the first state and the second state is variable, and the time of the other of the first state and the second state is fixed. One of the above is the first state.
The toilet seat device according to claim 5, wherein the other is the second state.

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