JPH1071105A - Capacitance type seating detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect seating at all times by providing a first electrode and a second electrode for constituting a capacitor for detection for detecting the change of capacitance by seating over the almost entire area of a seating part while keeping an almost fixed feeling. SOLUTION: The first and second electrodes 23 and 24 for constituting the capacitor 63 for the detection are arranged side by side and disposed within the almost same surface of a toilet seat with a narrow interval. At the time of seating from a non-seating state, the capacitance of the capacitor 63 for the detection of a resonance circuit 33 rapidly becomes large, the resonance frequency of the resonance circuit 33 becomes lower than the oscillation frequency of an oscillation circuit 32 and the output voltage of a rectifier circuit 35, that is the output voltage of an OP amplifier 36, steeply declines simultaneously with seating. To the contrary, since a reference voltage Vcom gradually drops by the time constant of a compensation circuit 38, the output voltage Vdel of the OP amplifier 36 is turned to the relation of Vdel <Vcom simultaneously with seating. Thus, the output voltage Vout of a comparator circuit 37 becomes a high level simultaneously with seating and thus, seating is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitance type seating detection device for detecting a seating based on a change in capacitance due to, for example, sitting on a toilet seat.

[0002]

2. Description of the Related Art Conventionally, various toilet bowls as shown in FIG. 6 have been proposed. The toilet 1 is a hot-water flush toilet, and a toilet seat 2 is rotatably mounted on an upper part of the toilet 1.
A lid 3 is rotatably attached so as to cover the toilet seat 2. A control box 4 is provided on the side of the toilet 1.
By operating various switches and the like provided in the control box 4, a heater embedded in the toilet seat 2 is turned on and off, its temperature is controlled, and a cleaning nozzle 5 provided in the toilet 1 is inserted and removed, and cleaning is performed. Water injection control, cleaning water temperature control, and the like are performed.

Here, insertion and removal of the washing nozzle 5, injection of washing water and heating of washing water are generally performed by operating a predetermined switch in a seated state. The toilet 1 is provided with a seating detection device for detecting seating.

Conventionally, as such a seating detecting device, for example, FIGS. 7A and 7B show a schematic plan view and an A-
The one shown in the A 'sectional view has been proposed. In this seating detection device, in order to spread the heat generated by the heater wire 6 provided inside the toilet seat 2 made of resin, the entirety of the upper surface (back surface) of the internal cavity portion facing the seating surface (front surface) of the toilet seat 2 is spread. An aluminum foil 7 is provided, the aluminum foil 7 for heat diffusion is used as one electrode, the other electrode is used as the ground, and a detection circuit 8 is connected between the ground and the aluminum foil 7. The seating is detected based on a change in capacitance between the ground and the aluminum foil 7 for heat diffusion due to the seating / non-seating. In FIG. 7A, reference numeral 9 denotes a temperature sensor for detecting the temperature of the toilet seat 2.

[0005] As another conventional seating detection device, as shown in FIG.
Further, there has been proposed an apparatus in which seats 0a and 10b are provided, and these electrodes are connected to a detection circuit to detect seating based on a change in capacitance between the electrodes 10a and 10b.

[0006]

However, in the conventional capacitance type seating detecting device shown in FIG. 7, the counter electrode of the heat diffusion aluminum foil 7 constituting the detecting capacitor for detecting the seating. Because it is ground, the environment where the toilet is installed, for example, whether the building is wooden or steel bar, whether it is close to the wall, whether there is a water tank with a large capacitance nearby, etc. If the user touches a grounded water pipe or the like, the magnitude of the output signal greatly changes, so that there is a problem that stable operation cannot be obtained.

In the case of FIG. 7, the heater wire 6 disposed close to the heat diffusion aluminum foil 7 is grounded via a commercial power supply system. A capacitance larger than the capacitance caused by sitting on the foil 7 is generated. For this reason, usually, a common mode choke coil is inserted between the heater wire 6 and the power supply so as to insulate the heater wire 6 from the ground. There is also a problem that the magnitude of the signal to be performed is not stable and malfunctions.

Further, in the conventional electrostatic capacitance type seating detecting device shown in FIG. 8, a pair of electrodes 10a and 10b constituting a detecting capacitor for detecting seating is provided with a toilet seat 2.
Since it is provided only on the both sides of the rear part, there is a problem that the detection becomes impossible depending on the sitting posture.

The present invention has been made in view of such a conventional problem, and has been appropriately configured so as to always reliably detect a seat without being affected by an installation environment, a seating posture, and the like. It is an object of the present invention to provide a capacitance type seating detection device.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a capacitance type seating detection device which detects a seating based on a change in capacitance due to the seating, and covers almost the entire area of the seating portion. The first electrode and the second electrode constituting a detection capacitor for detecting a change in capacitance due to seating are provided at substantially constant intervals.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1A and 1B are a schematic plan view and a cross-sectional view taken along the line BB ', respectively, showing a main part of an embodiment of the present invention. This embodiment detects the seating of a human body on a hot water flush toilet, and the toilet seat 21 constituting the seating portion is formed of an insulating material such as resin.
On the upper surface (back surface) of the internal cavity facing the seating surface (front surface) on which the human body is seated,
Partition pieces 22a and 22b having a width of about 1 mm to 10 mm are formed in parallel at substantially constant intervals.

On the back surface on which the partition pieces 22a and 22b are formed, provided between the partition pieces 22a and 22b is a first electrode 23 constituting a detection capacitor for detecting a change in capacitance due to seating. A second electrode 24, which is an electrode opposite to the first electrode 23, is provided on the back surface of the other portions. These first and second electrodes 23 and 24 are made of, for example, aluminum foil. In this manner, the first electrode 23 and the second electrode 24 that constitute a detection capacitor for detecting a change in capacitance due to sitting over substantially the entire area of the seating portion are substantially flush with each other. It is provided at substantially constant intervals (1 mm to 10 mm) within the back surface).

Further, the toilet seat 21 has a second
A heater wire 25 for heating the toilet seat 21 and a temperature sensor 26 for detecting the temperature of the toilet seat 21 are provided in the vicinity of the electrode 24. The heater wire 25 and the temperature sensor 26 are connected to a known temperature control device (not shown), and the heat generated by the heater wire 25 is diffused by the second electrode 24 to heat the toilet seat 21. Along with
The temperature is detected by the temperature sensor 26, and the toilet seat 21 is heated to a desired temperature.

In this embodiment, the first electrode 23 and the second electrode 24 are connected to a detection circuit 30, and the detection circuit 30 allows the first and second electrodes 2 to be seated and unseated.
Seating is detected based on the change in the capacitance between 3 and 24. Hereinafter, the configuration of the detection circuit 30 will be described.

FIG. 2 shows an example of the configuration of the detection circuit 30. The detection circuit 30 includes a coupling transformer 31,
It has an oscillation circuit 32, a resonance circuit 33, a filter circuit 34, a rectifier circuit 35, an OP amplifier 36, a comparison circuit 37, and a compensation circuit 38.

The oscillation circuit 32 comprises an LC oscillation circuit using the primary coil 41 of the coupling transformer 31 as an inductive element. The oscillation circuit 32 has two NPN transistors 51 and 52, the collector of one of which is connected to the power supply terminal of the voltage Vcc through the resistor 53, and the emitter of the transistor 51 through the parallel circuit of the capacitor 54 and the resistor 55. Ground. The bases of the transistors 51 and 52 are commonly connected and connected to a power supply terminal of a voltage Vcc via a resistor 56. The collector of the transistor 52 is open, the emitter is grounded via the primary coil 41 of the coupling transformer 31, and is connected to the emitter of the transistor 51 via the capacitor 57. In this manner, an LC oscillation circuit is formed in which the potentials at both ends of the capacitor 57 are made substantially the same. In this embodiment, the oscillation frequency f of the oscillation circuit 32 is about 500 KHz at room temperature of 20 ° C.

The resonance circuit 33 is constituted by connecting a secondary coil 42 of the coupling transformer 31, a semi-fixed capacitor 61 for adjustment, and a series circuit of a capacitor 62 and a detection capacitor 63 in parallel. In the state, the oscillation circuit 32
Is adjusted so as to obtain a resonance frequency substantially equal to the oscillation frequency of. Here, the detection capacitor 63 is configured by the first electrode 23 and the second electrode 24 shown in FIG. 1, and the first electrode 23 is connected to the capacitor 62 and the second electrode 2.
4 is connected to ground. Therefore, since the capacitance of the detection capacitor 63 increases when the user sits, the resonance frequency of the resonance circuit 33 is lower when the user is seated than when the user is not seated.

The output of the resonance circuit 33 is supplied to a filter circuit 34.
To the rectifier circuit 35 via The filter circuit 34
It comprises a series resonance circuit of a capacitor 71 and a coil 72, and its resonance frequency is made substantially equal to the oscillation frequency of the oscillation circuit 32. The rectifier circuit 35 includes a voltage doubler circuit composed of diodes 75 and 76, a capacitor 77 and a resistor 78 connected in parallel between the output terminal of the voltage doubler circuit and ground.
5 is supplied to the non-inverting input terminal of the OP amplifier 36.

The OP amplifier 36 is a voltage follower having its output terminal connected to its inverting input terminal.
The output (V _det ) of the P-amplifier 36 is supplied to the inverting input terminal of the comparison circuit 37, and the comparison circuit 37
To the non-inverting input terminal. The compensation circuit 38 is connected to the non-inverting input terminal of the comparison circuit 37, and a feedback resistor 82 is connected to the output terminal of the comparison circuit 37.
A voltage based on the output of the resonance circuit 33 is applied as the reference voltage _Vcom . Further, the compensating circuit 38 includes a capacitor 84 and a resistor 85 connected in parallel between the non-inverting input terminal of the comparing circuit 37 and the ground.

Thus, in the comparison circuit 37,
The output voltage of the rectifier circuit 35, that is, the output voltage V _det of the OP amplifier 36, is compared with the reference voltage V _com from the compensation circuit 38. When V _det falls below V _com , the output of the comparison circuit 37 becomes high level. A voltage _Vout is output to detect seating.

In this embodiment, the first electrode 23 and the second electrode 24 forming the detection capacitor 63 are
Since the toilet seats 21 are arranged side by side in a substantially same plane at a narrow interval of 1 mm to 10 mm, the area where the electrodes 23 and 24 face each other is very small. Therefore, in the non-seated state, the capacitance of the detection capacitor 63 is extremely small, and in this state, the resonance frequency of the resonance circuit 33 is adjusted to be substantially equal to the oscillation frequency of the oscillation circuit 32. 3, the reference voltage V _com becomes lower than the output voltage V _det of the OP amplifier 36, and the output voltage V _out of the comparison circuit 37 becomes low level, as shown in FIG.

When the user sits down from the unseated state, the capacitance of the detection capacitor 63 of the resonance circuit 33 rapidly increases, and as shown in FIG.
_g is lower than the oscillation frequency f _o of the oscillator circuit 32,
The output voltage of the rectifier circuit 35, that is, the output voltage V _det of the OP amplifier 36, drops sharply at the time of sitting. On the other hand, since the reference voltage V _com gradually decreases due to the time constant of the compensation circuit 38, the output voltage V
_{The det} has a relationship of V _det <V _{com at} the same time as the seating.
Therefore, the output voltage V _out of the comparison circuit 37 becomes high level at the same time as the user sits down, whereby the seating can be detected.

According to this embodiment, the first electrode 23 and the second electrode 24 forming the detection capacitor 63 for detecting a change in capacitance due to sitting over almost the entire area of the toilet seat 21. Were provided at almost constant intervals,
Even if a part of the human body is separated from the toilet seat 21 or the foot is separated from the floor in a seated state, the seating can be reliably detected. In addition, since the ground is not used as an electrode of the detection capacitor 63, the environment in which the toilet is installed, for example, whether the building is wooden or steel, whether it is close to a wall, whether there is a water tank with a large capacitance nearby, or not. In addition to being affected by such a situation, even if the user touches a grounded water pipe or the like while sitting, the seating can be reliably detected. Further, since the heater wire 25 is disposed close to the second electrode 24 to be grounded, even if the common mode choke coil is not inserted into the cable connecting the heater wire 25 to the commercial power supply, the heater wire 25 can be seated. Can be reliably detected.

The rectifier circuit 35 and the compensation circuit 38
Is coupled to the resonance circuit 33, so that the oscillation circuit 32
Of the oscillation amplitude of the rectifier circuit 35, the output voltage V
_{The det} and the reference voltage _Vcom of the compensating circuit 38 also vary. Therefore, even if the oscillation frequency f of the oscillation circuit 32 fluctuates due to the temperature change and the oscillation amplitude fluctuates, the seating can always be reliably detected.

Further, since a filter circuit 34 having a series resonance frequency substantially equal to the oscillation frequency of the oscillation circuit 32 is provided between the resonance circuit 33 and the rectification circuit 35, frequency components which are not related to the detection of seating such as noise can be eliminated. It can be cut effectively.
Furthermore, since the output of the rectifier circuit 35 is supplied to the comparison circuit 37 and the compensation circuit 38 via the voltage follower OP amplifier 36, the linearity of the output (V _det ) of the rectifier circuit 35 can be improved. .

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified or changed. For example, in FIG.
a, 22b may be omitted, and the first electrode 2b may be omitted as shown in FIG.
Steps 21a are formed in portions where
The first electrode 23 may be provided in the inside. Further, the detection circuit that detects the seating based on the change in the capacitance of the detection capacitor is not limited to the configuration illustrated in FIG. 2, and other known circuits can be used. Further, the present invention is not limited to the seating of a human body on a toilet bowl, and can be widely applied to the detection of a seating of a human body or the like.

[0027]

As described above, according to the present invention, the first electrode and the second electrode constituting the detecting capacitor for detecting the change in the capacitance due to the seating are substantially connected to the seating portion. Since it is provided at substantially constant intervals over the entire area, it is possible to always reliably detect seating without being affected by the installation environment of the seating portion, the seating posture, and the like.

[Brief description of the drawings]

FIG. 1 is a diagrammatic plan view and BB 'sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of an example of a detection circuit illustrated in FIG. 1;

FIG. 3 is a diagram for explaining an operation of the detection circuit shown in FIG. 2;

FIG. 4 is a diagram for explaining the operation.

FIG. 5 is a sectional view showing a main part of another embodiment of the present invention.

FIG. 6 is a diagram showing an example of a toilet to which the capacitance-type seating detection device according to the present invention can be applied.

FIG. 7 is a diagrammatic plan view and an AA ′ cross-sectional view for explaining an example of a conventional capacitance-type seating detection device.

FIG. 8 is a diagrammatic plan view for explaining another example.

[Explanation of symbols]

 Reference Signs List 21 toilet seat 21a step 23 first electrode 24 second electrode 25 heater wire 26 temperature sensor 30 detection circuit 63 detection capacitor

Claims (1)

[Claims] 1. A capacitance type seating detection device for detecting a seating based on a capacitance change due to a seating, wherein a detection for detecting a capacitance change due to the seating over substantially the entire area of a seating portion. A first electrode and a second electrode constituting a capacitor for use are provided at substantially constant intervals.