JP7620840B2 - Bathtub equipment - Google Patents

Description

The present invention relates to a bathtub device, and in particular to a bathtub device equipped with a function for detecting the state of a bather.

In recent years, the number of people drowning in bathtubs installed in ordinary homes has been on the rise, and there is an increasing need for measures to prevent drowning accidents in bathtubs. As a measure against such drowning accidents in bathtubs, bathtub devices equipped with a function to monitor the safety of bathers using various sensors installed in the bathtub have been known for some time.

Patent Document 1 (JP Patent Publication 2005-224299) describes a bathtub management system and a bathtub management program. In this bathtub management system, a microwave oscillator installed in the bathroom irradiates microwaves to a bather sitting in the bathtub, and the bather's heart rate and body movements are measured based on the waves reflected from the bather. The irradiated microwaves are reflected by the bather's chest, which is exposed above the water surface of the bathtub, and the bather's body movements are detected based on the received reflected waves. If no body movements are observed, it is assumed that the bather is dozing off, and an alarm is sounded to prevent the bather from dozing off.

Patent Document 2 (JP Patent Publication 2002-288755) describes a hot water appliance. In this hot water appliance, a human body sensor is attached to the wall of the bathroom, and an imaging device using an artificial retina provided in this human body sensor captures images of human body movements in the bathroom and performs image processing. The human body sensor also includes an infrared sensor that detects human body heat by infrared light. When the human body sensor detects that human body movements have stopped, an alarm is issued by an alarm means.

Patent Document 3 (JP Patent Publication 2020-112850) describes a bath water heater. This bath water heater is equipped with a pyroelectric sensor as a human presence sensor that detects the amount of temperature change of a heat source within a detection area, and determines whether a person is moving while bathing based on the detection results of the human presence sensor. If the state in which the human presence sensor determines that the person is not moving continues for a predetermined period of time, an alert is issued to encourage movement.

JP 2005-224299 A JP 2002-288755 A JP 2020-112850 A

Thus, conventional devices for detecting the state of a bather mainly detect the body movements of the bather above the water surface and use this to detect whether the bather is dozing off, etc. However, the present inventors conducted extensive research into body movements while bathing and discovered that when a person is relaxed, there is little movement on or above the water surface, and more movement below the water surface. In a relaxed bathing position, the bather's central part is supported by the bathtub wall and only the arms and legs move, so the upper body above the water surface does not move significantly and large waves do not occur in the water in the bathtub.

In addition, because the hands and feet of a person immersed in the bathtub are covered in hot water, it is difficult for an infrared sensor or other device to detect the movement of the hands and feet as a movement of a heat source. In other words, conventional devices have the problem of being prone to false detection when there is little body movement on or above the water surface, such as when the bather is relaxed in the bathtub.
In addition, when using a bathing device such as a shoulder bath while bathing, the chest and upper body are covered with a film of water, so only parts of the body supported by the bathtub pillow, such as the face, can be measured. There is also a risk that the high temperature running water will be detected as the movement of a heat source, making it difficult to detect body movement using pyroelectric sensors or microwave sensors.

Therefore, the present invention aims to provide a bathtub device that can accurately detect the condition of a bather.

In order to solve the above-mentioned problems, the present invention is a bathtub device with a function for detecting the state of a bather, characterized by having a bathtub body, a set of electrodes for acquiring a potential waveform signal through hot and cold water stored in the bathtub body, a filter circuit for attenuating the components of the bather's electrocardiogram signal contained in the potential waveform signal acquired by the electrodes and extracting a low-frequency signal from the potential waveform signal, and a determination circuit for determining the presence or absence of body movement of the bather based on the low-frequency signal.

In the present invention configured in this way, a set of electrodes acquires a potential waveform signal through the hot and cold water stored in the bathtub body, and a filter circuit attenuates the components of the bather's electrocardiogram signal contained in the potential waveform signal, and a low-frequency signal is extracted. A determination circuit determines the presence or absence of body movement of the bather based on the extracted low-frequency signal.

As mentioned above, when a bather is in a relaxed state (relaxed), the bather's body movements become less, making it difficult to distinguish between this state and a state where the bather is dozing off or has impaired consciousness. The present inventors have conducted extensive research to distinguish between these two states, and have discovered that while a bather's body movements completely stop when dozing off or has impaired consciousness, when in a relaxed state, gentle body movements (shaking of the arms and legs) take place in the water of the bathtub. Furthermore, the above-mentioned gentle body movements are not large enough to ruffle the water in the bathtub, making it difficult to detect them by measuring the movement of the water surface from outside the bathtub.

The inventors discovered that the bather's movements below the surface of the bathtub are reflected as a change in the impedance of the water stored in the bathtub body, and that this change in impedance can be detected by acquiring a potential waveform signal using a set of electrodes. However, when the potential waveform signal is acquired via the water stored in the bathtub body, the bather's heartbeat is mixed in as a large-amplitude potential waveform signal, making it difficult to accurately detect the bather's gradual body movements.

According to the present invention configured as described above, a potential waveform signal is acquired through the hot water stored in the bathtub body, and the components of the bather's electrocardiogram signal from the acquired potential waveform signal are attenuated by a filter circuit to extract a low-frequency signal. Furthermore, based on the extracted low-frequency signal, a determination circuit determines whether or not the bather is moving, so that it is possible to determine whether or not the bather is making gentle body movements in the hot water stored in the bathtub body, and the bather's condition can be accurately detected. The acquired electrocardiogram signal can also be used to detect the bather's heart rate from the electrocardiogram signal.

In the present invention, preferably, the device further includes an alarm device that notifies the presence or absence of body movement of the bather determined by the determination circuit to the bathroom in which the bathtub body is installed and/or outside the bathroom.

According to the present invention configured in this way, by notifying inside the bathroom that the bather is not moving, a bather who has fallen into a light drowsy state can be woken up on his/her own. In addition, by notifying outside the bathroom that the bather is not moving, if the bather loses consciousness, it is possible to prompt people outside the bathroom to check on the bather's safety, making it possible to prevent drowning in the bathtub. In addition, by notifying inside the bathroom that there is movement, the bather can be aware that he/she is bathing safely. In addition, by notifying outside the bathroom that the bather is moving, people outside the bathroom can recognize that the bather is bathing safely.

In the present invention, preferably, the judgment circuit judges that the bather is not moving if the low-frequency signal does not exceed a predetermined judgment criterion threshold within a predetermined judgment time.

A relaxed bather may go through a period of time in which no body movement is detected, even if the bather is awake. With the present invention configured as described above, the determination circuit determines that the bather is not moving if the low-frequency signal does not exceed a predetermined determination criterion threshold within a predetermined determination time, making it possible to effectively distinguish between a relaxed state and a dozing state.

In the present invention, the determination circuit preferably changes the determination criterion threshold or the determination time for determining the presence or absence of body movement of the bather based on a predetermined condition.
The potential waveform signal acquired by the electrodes changes in various ways, influenced not only by the body movement of the bather, but also by the characteristics of the bather and the environment inside the bathtub body. Therefore, if the judgment circuit always judges the presence or absence of body movement of the bather using the same judgment criteria, it may not be able to detect body movement even when it is present, or may judge that there is body movement even when the bather is dozing. According to the present invention configured as described above, the judgment criteria for judging the presence or absence of body movement of the bather can be changed, so that the presence or absence of body movement of the bather can be accurately judged under various conditions.

In the present invention, the determination circuit preferably changes the determination reference threshold value based on the potential waveform signal.
The potential waveform signal acquired by the electrodes changes in various ways depending on the bather's body movements as well as the bather's physique, bathing position, posture, the state of the water in the bathtub body, etc. In particular, these influences cause the amplitude of the potential waveform signal to change. According to the present invention configured as described above, the judgment circuit changes the judgment reference threshold value based on the potential waveform signal, so that it is possible to accurately judge the presence or absence of the bather's body movements even if the amplitude of the potential waveform signal changes overall.

In the present invention, the decision circuit preferably successively updates the decision reference threshold in a decreasing direction based on the low-frequency signal.
The low-frequency signal, which is the result of attenuating the components of the electrocardiogram signal, mainly contains components that represent the body movement of the bather, and a state in which the amplitude of the low-frequency signal is reduced can be interpreted as indicating a state in which the bather has little body movement. According to the present invention configured as described above, the judgment criterion threshold is updated in a decreasing direction based on the low-frequency signal, so that the judgment criterion threshold can be made to asymptotically correspond to the amplitude of the low-frequency signal when the bather has no body movement.

In the present invention, the determination circuit preferably changes the determination time based on the potential waveform signal.
The period of the low-frequency signal is affected by the period of the bather's body movement. Therefore, if the same judgment time is always used to judge whether or not the bather is moving, erroneous judgments may occur depending on the tendency of the bather's body movement. According to the present invention configured as described above, the judgment time is changed based on the potential waveform signal, so that erroneous judgments based on the period of the bather's body movement can be suppressed.

In the present invention, the determination circuit preferably changes the determination time based on the time that has elapsed since the bather entered the bathtub body.
Generally, immediately after immersing in the bathtub, a bather remains still and makes relatively few body movements in order to get used to the temperature of the water in the bathtub body, but as time passes, the bather begins to wipe away sweat caused by sweating, knead their hands, and other relaxing actions, and body movements tend to gradually increase. Also, bathers tend to fall asleep after a certain amount of time has passed since immersing in the bathtub. According to the present invention configured as described above, the judgment time is changed based on the elapsed time after the bather entered the bathtub body, so that the presence or absence of the bather's body movement can be appropriately judged according to the behavior pattern.

In the present invention, preferably, when the determination circuit determines that it is difficult to determine the presence or absence of body movement of the bather based on the potential waveform signal, the notification device notifies the user inside and/or outside the bathroom of this fact.

The potential waveform signal may not be able to be adequately detected, for example, when the bather's position or posture in the bathtub body or when a large amount of bath additives has been added, making it difficult to determine whether the bather is moving or not. According to the present invention configured as described above, when it is difficult to determine whether the bather is moving or not, the bather can be alerted to this by being notified inside the bathroom, such as by encouraging the bather to change his/her bathing position, and can be alerted to this outside the bathroom, such that people outside the bathroom can be alerted to pay attention to the bather's condition.

The bathtub device of the present invention can accurately detect the condition of the bather.

1 is a perspective view showing an entire bathroom in which a bathtub apparatus according to an embodiment of the present invention is installed. 1 is a cross-sectional view showing the structure of an electrode provided in a bathtub apparatus according to an embodiment of the present invention. 10 is a block diagram showing the processing of an acquired potential waveform signal in a bathtub apparatus according to an embodiment of the present invention. FIG. 4 is a flowchart showing the operation of a bathtub apparatus according to an embodiment of the present invention. 11 is a potential waveform signal showing an example of a state in which the body movement of a bather cannot be detected normally. 13A and 13B are diagrams showing an example of a potential waveform signal before and after a bather immerses himself in hot water in the bathtub body. 7 is a diagram showing a potential waveform signal obtained by enlarging a part of the potential waveform signal shown in the upper part of FIG. 6. FIG. 13 is a diagram showing an example of a potential waveform signal when a bather makes a body movement. FIG. 1 is a diagram showing a typical human electrocardiogram signal waveform. FIG. 2 is a diagram showing frequency bands in which each wave included in an electrocardiogram signal waveform appears. 1A and 1B are diagrams illustrating an example of a low-frequency signal obtained when the cutoff frequency of a filter circuit is variously changed. A figure showing an example of a change in a potential waveform signal due to a change in a bather's position in the bathtub body. A figure showing an example of a change in potential waveform signal depending on the presence or absence of bath additives added to the hot water in the bathtub body. 1A and 1B are diagrams showing an example of changes in a low-frequency signal and its frequency power spectrum when a bather makes body movements and when he or she does not make body movements. FIG. 11 is a diagram showing the relationship between a low-frequency signal and a set judgment criterion threshold value. 13 is a diagram showing an example of a potential waveform signal after a bather enters the bathtub body. FIG.

Next, a bathtub apparatus according to an embodiment of the present invention will be described with reference to the accompanying drawings.
Fig. 1 is a perspective view showing an entire bathroom in which a bathtub apparatus according to an embodiment of the present invention is installed. Fig. 2 is a cross-sectional view showing the structure of electrodes provided in the bathtub apparatus according to an embodiment of the present invention. Fig. 3 is a block diagram showing the processing of an acquired potential waveform signal in the bathtub apparatus according to an embodiment of the present invention.

As shown in FIG. 1, the bathtub apparatus 1 according to an embodiment of the present invention comprises a bathtub body 2, a negative electrode 4a, a positive electrode 4b, and a reference electrode 4c attached to the bathtub body 2, and a signal processing device 6 for processing signals acquired by the electrodes, and is installed in a bathroom R. A remote control 6a is also attached to the wall of the bathroom R, and this remote control 6a can be used to operate the function of the bathtub apparatus 1 for detecting the state of the bather. Furthermore, in this embodiment, the bathtub apparatus 1 is placed on one side of the bathroom R so that it is in contact with the wall.

The bathtub body 2 is formed in a roughly rectangular box shape in a plan view, and is configured to store hot and cold water inside. In this embodiment, the bathtub body 2 is positioned so that one long side and the entire two short sides on either side of it are in contact with the inner wall surface of the bathroom R. The inner wall surface that constitutes one short side of the bathtub body 2 is configured as a backrest surface 2a against which the bather can lean. An apron 2b is removably attached to the long side of the bathtub body 2 that is not in contact with the inner wall surface of the bathroom R.

The negative electrode 4a and the positive electrode 4b are a pair of electrodes attached to the bathtub body 2 in order to detect a potential waveform signal through the hot and cold water stored in the bathtub body 2. The bather's electrocardiogram signal is obtained as a signal of the potential difference between these negative electrode 4a and positive electrode 4b. The pair of electrodes consisting of the negative electrode 4a and the positive electrode 4b are both arranged on the backrest surface 2a that constitutes the short side of the bathtub body 2. The reference electrode 4c is an electrode for obtaining a reference potential of the potential detected by the negative electrode 4a and the positive electrode 4b, and this electrode is also arranged on the backrest surface 2a of the bathtub body 2. Thus, in the bathtub device 1 of this embodiment, all of the electrodes for obtaining the electrocardiogram signal are arranged on one backrest surface 2a.

The negative electrode 4a and the positive electrode 4b are arranged on the left and right of the center line of the horizontal direction (width direction) of the backrest surface 2a, in positions symmetrical with respect to the center line. That is, the negative electrode 4a and the positive electrode 4b are arranged on the backrest surface 2a at a distance from the center line in the left and right directions. Furthermore, the negative electrode 4a and the positive electrode 4b are arranged at a height of about 300 mm from the bottom surface of the bathtub body 2 so as to be located below the water surface in the bathtub body 2. The negative electrode 4a and the positive electrode 4b can be attached below the water surface in the bathtub body 2 and at a height position above the reference electrode 4c. On the other hand, the reference electrode 4c is arranged on the center line of the backrest surface 2a, below the negative electrode 4a and the positive electrode 4b. The reference electrode 4c is not necessarily provided and can be omitted. At least one pair of electrodes is required to detect the potential waveform signal, and for example, two or more pairs of negative electrodes 4a and positive electrodes 4b may be arranged.

Next, the structure of each electrode will be described with reference to FIG.
Although the structure of the negative electrode 4a will be described here, in this embodiment, the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c all have the same structure.

As shown in FIG. 2, the negative electrode 4a has an electrode portion 10, a front gasket 12a, a rear gasket 12b, a flange 14, a moisture-proof tube 16, a connection terminal 18, a fixing screw 20, a conductor 22, and a sheath 24. The negative electrode 4a is attached so as to be exposed on the surface of the backrest surface 2a of the bathtub body 2, and the gasket ensures watertightness between the negative electrode 4a and the backrest surface 2a.

The electrode section 10 is a conductive metal part, and is composed of a disk section 10a formed in a disk shape and a shaft section 10b protruding vertically from the back of the disk section 10a. The disk section 10a is a thin disk-shaped part, and the front surface of the disk section 10a is exposed on the surface of the backrest surface 2a and is configured to detect the electric potential. That is, in this embodiment, the disk section 10a is formed with a diameter of about 15 mm and a thickness of about 2.5 mm, and the entire disk section 10a is disposed on the surface of the backrest surface 2a. The shaft section 10b is a round bar-shaped part extending at a right angle from the center of the back of the disk section 10a, and protrudes to the back side of the backrest surface 2a through a through hole formed in the backrest surface 2a. In addition, a male screw thread is formed in the middle part of the shaft section 10b, and a fixing section for fixing the connection terminal 18 is formed at the tip.

The front gasket 12a is a disc-shaped member made of rubber, and has a circular hole in the center for passing the shaft portion 10b of the electrode portion 10 through. The front gasket 12a has approximately the same diameter as the disc portion 10a of the electrode portion 10, and is disposed on the rear side of the disc portion 10a. When the negative electrode 4a is attached to the backrest surface 2a, the front gasket 12a is sandwiched between the rear side of the disc portion 10a and the surface of the backrest surface 2a, ensuring watertightness between the backrest surface 2a and the negative electrode 4a.

The back gasket 12b is a disc-shaped member made of rubber, and has a circular hole in the center for passing the shaft portion 10b of the electrode portion 10 through. The back gasket 12b has a diameter larger than that of the front gasket 12a and is approximately the same as the large diameter portion of the flange 14, and is placed on the back side of the backrest surface 2a. When the negative electrode 4a is attached to the backrest surface 2a, the back gasket 12b is sandwiched between the back surface of the backrest surface 2a and the end face of the flange 14, ensuring watertightness between the rear surface of the backrest surface 2a and the negative electrode 4a. The front gasket 12a and the back gasket 12b may be made of resin.

The flange 14 is a stepped cylindrical member consisting of a large diameter portion and a small diameter portion, and a female thread is formed in the center to allow the shaft portion 10b of the electrode portion 10 to pass through. The large diameter portion of the flange 14 is formed to have approximately the same diameter as the back gasket 12b, and the small diameter portion is formed on the back side of the large diameter portion. By screwing and tightening the female thread formed to pass through the flange 14 and the male thread formed on the shaft portion 10b of the electrode portion 10, the end face of the large diameter portion of the flange 14 presses the back gasket 12b against the back of the backrest surface 2a, ensuring watertightness.

The moisture-proof tube 16 is a long, thin rubber tube that is arranged to cover the tip of the shaft portion 10b of the electrode portion 10, the connection terminal 18, the conductor wire 22, etc. The small diameter portion of the flange 14 is fitted into the tip of the moisture-proof tube 16 to prevent moisture from entering the moisture-proof tube 16. The moisture-proof tube 16 may be made of resin.

The connection terminal 18 is a conductive metal component, and is crimped and connected to the tip of the conductor 22. A hole is provided at the tip of the connection terminal 18 for passing a fixing screw 20 through, and the connection terminal 18 can be fixed to the electrode part 10 by threading the fixing screw 20 through this hole into a female thread provided at the tip of the shaft part 10b of the electrode part 10. This allows the electrode part 10 and the conductor 22 to be electrically connected in a detachable manner.

The conductor 22 is a conductive wire for electrically connecting the electrode unit 10 and the signal processing device 6 (Figure 1), and extends from the negative electrode 4a to the signal processing device 6. The conductor 22 is covered with a sheath 24 made of an insulating material to ensure electrical insulation of the conductor 22. In this embodiment, the conductors 22 extending from the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are connected to the signal processing device 6, and the electrocardiogram signal is input to the signal processing device 6.

Next, the configuration of the signal processing device 6 will be described with reference to FIG.
The signal processing device 6 is an electric circuit to which the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are connected, and is disposed on the rear side of the backrest surface 2a of the bathtub body 2. The signals acquired by the negative electrode 4a, the positive electrode 4b, and the reference electrode 4c are processed by the signal processing device 6 and sent to the remote control 6a. The remote control 6a uses the potential waveform signals acquired by each electrode (negative electrode 4a, positive electrode 4b, and reference electrode 4c) to determine whether or not the bather is moving. If it is determined that the bather is not moving, the remote control 6a located in the bathroom R notifies the bather that the bather is not moving, and also notifies a display device (not shown) located outside the bathroom R. On the other hand, if it is determined that the bather is moving, the remote control 6a located in the bathroom R notifies the bather that the bather is moving, and also notifies a display device (not shown) located outside the bathroom R. Therefore, the remote control 6a placed in the bathroom R and a display device (not shown) placed outside the bathroom R function as an alarm device that notifies the bather that there is no body movement.

As shown in FIG. 3, the signal processing device 6 has a differential amplifier circuit 26, an A/D converter 32, and an interface circuit 34, and these circuits are housed within a housing 6b.
The differential amplifier circuit 26 is an amplifier circuit to which the conductors 22 extending from the negative electrode 4a and the positive electrode 4b are connected, and is configured to receive and amplify the difference voltage between the negative electrode 4a and the positive electrode 4b as a potential waveform signal. The conductor 22 extending from the reference electrode 4c is connected to the ground of the differential amplifier circuit 26.

The A/D converter 32 is configured to convert the potential waveform signal, which is an analog signal amplified by the differential amplifier circuit 26, into a digital signal.
The interface circuit 34 is configured to receive the digital signal that has been A/D converted by the A/D converter 32 and to send the input digital signal to the remote control 6a and/or an external display device (not shown), etc.

The remote control 6a includes a filter circuit 36a that attenuates the components of the bather's electrocardiogram signal contained in the digitized potential waveform signal and extracts a low-frequency signal from the potential waveform signal, a judgment circuit 36b that judges the presence or absence of the bather's body movement based on the low-frequency signal, a display unit 36c that displays the setting state of the bathtub device 1, a speaker 36d that emits an alarm sound, and a communication unit 36e. In this embodiment, the filter circuit 36a and the judgment circuit 36b are composed of a microprocessor and memory built into the remote control 6a, and software that operates these. As a modified example, the present invention can also be configured so that the filter circuit and judgment circuit are composed of hardware circuits and the low-frequency signal is extracted by an analog filter to make a judgment.

The potential waveform signal input to the remote control 6a is input to the filter circuit 36a, where the components of the bather's electrocardiogram signal are attenuated to extract a low-frequency signal. The judgment circuit 36b judges the presence or absence of the bather's body movement based on the low-frequency signal, and if it is judged that the bather has no body movement, the display unit 36c displays that the bather has no body movement and a warning sound is emitted from the speaker 36d. In addition, the communication unit 36e transmits a control signal to a display device (not shown) arranged outside the bathroom R, which displays that the bather has no body movement and emits a warning sound. This allows the bather's condition to be monitored from outside the bathroom R. Alternatively, the present invention can be configured so that the filter circuit 36a and the judgment circuit 36b are built into a display device (not shown) outside the bathroom R. In addition, the communication unit 36e is configured to send signals to a water discharge device (not shown) provided in the bathtub device 1 and an air blower device (not shown) provided in the bathroom R, and to operate them. Furthermore, the present invention can be configured so that the communication unit 36e can send signals to the smartphone of the person taking the bath or a family member to notify them of the bather's condition.

In this embodiment, the conductors 22 extending from each electrode and the signal processing device 6 to which these conductors 22 are connected are all housed in the space behind the backrest surface 2a of the bathtub body 2. As shown in FIG. 1, the space behind the backrest surface 2a can be accessed from the washing area side of the bathroom R by removing the apron 2b of the bathtub body 2. Therefore, by simply removing the apron 2b of the bathtub body 2, maintenance such as adjustment and repair of each electrode and the signal processing device 6 can be easily performed. In other words, by arranging the negative electrode 4a, positive electrode 4b, reference electrode 4c, and signal processing device 6 in a concentrated and easily accessible space, maintainability can be improved.

Next, the operation of the bathtub apparatus 1 according to the embodiment of the present invention will be described with reference to FIGS.
Fig. 4 is a flow chart showing the operation of the bathtub equipment 1 according to the embodiment of the present invention. Figs. 5 to 16 are diagrams for explaining the process in the flow chart of Fig. 4.

The flowchart shown in FIG. 4 is repeatedly executed at predetermined time intervals by a microprocessor built into the remote controller 6a while the bathtub equipment 1 is powered on.
First, in step S1 of FIG. 4, a potential waveform signal digitized by the A/D converter 32 of the signal processing device 6 is input to the remote control 6a.

Next, in step S2, it is determined whether the bather's body movements can be detected normally. If the body movements can be detected normally, the process proceeds to step S3. If the body movements cannot be detected normally, the process proceeds to step S10. That is, the body movements of the bather are detected based on the potential waveform signal, which is a signal of the potential difference between the negative electrode 4a and the positive electrode 4b, via the hot water stored in the bathtub body 2. However, if the hot water is not stored in the bathtub body 2, or if the water level in the bathtub body 2 is low and the hot water is not in contact with the negative electrode 4a and the positive electrode 4b, the potential of each electrode is not determined and the potential waveform signal cannot be obtained. In such a state, the body movements of the bather cannot be detected, so in step S10, a notice to that effect is issued, and one processing cycle of the flowchart shown in FIG. 4 is terminated. In step S10, the fact that the bathtub device 1 is not detecting the state of the bather is displayed on the display unit 36c of the remote control 6a and on a display device (not shown) outside the bathroom R.

FIG. 5 shows a potential waveform signal showing an example of a state in which the body movement of a bather cannot be detected normally.
At times _t0 to _t1 in FIG. 5, the hot water in the bathtub body 2 is not in contact with the negative electrode 4a and the positive electrode 4b, and the potential difference between the negative electrode 4a and the positive electrode 4b is indefinite. In this state, the potential difference signal (potential waveform signal) has a large amplitude random noise waveform. Furthermore, at times _t1 to _t2 in FIG. 5, the water level in the bathtub body 2 rises, and the hot water in the bathtub body 2 begins to contact the negative electrode 4a and the positive electrode 4b. Next, at time _t2 , the negative electrode 4a and the positive electrode 4b are submerged in the hot water in the bathtub body ₂ , so the potential difference between the electrodes stabilizes, and the potential waveform signal becomes a small amplitude signal. If the potential waveform signal is in a state after time t2, the body movement of the bather can be detected normally. In step S2, based on the state of the potential waveform signal, it is determined whether or not the body movement of the bather can be detected normally.

Next, in step S3 of FIG. 4, it is determined whether the bather's electrocardiogram waveform has been detected. If the electrocardiogram waveform has been detected, the process proceeds to step S4. If the electrocardiogram waveform has not been detected, the process proceeds to step S10, and then the process of the flowchart shown in FIG. 4 is terminated. The bathtub device 1 of this embodiment is a device that detects the body movement of the bather. When the bather is sitting near the backrest surface 2a of the bathtub body 2, the bather's electrocardiogram waveform is observed by the negative electrode 4a and the positive electrode 4b. In other words, when the bather is bathing near the backrest surface 2a of the bathtub body 2, the components of the bather's electrocardiogram signal are mixed into the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b. Even if hot water is stored in the bathtub body 2, if there is no bather in the bathtub body 2, the body movement of the bather cannot be detected.

In step S3, it is determined whether or not a bather is in the bathtub body 2 based on whether or not an electrocardiogram signal component is present in the potential waveform signal. If no electrocardiogram signal component is present, it is determined that no bather is in the bathtub body 2, and one processing cycle of the flowchart shown in FIG. 4 is terminated. If it is determined that no bather is present, in step S10, the display unit 36c of the remote control 6a displays a message indicating that no body movement is being detected. Therefore, if the message indicates that no body movement is being detected even though the bather is in the bathtub body 2, the bather can, if necessary, change his or her seating position in the bathtub body 2 so that body movement can be detected.

Figure 6 shows an example of a potential waveform signal before and after a bather immerses himself in the hot water in the bathtub body 2. The top part of Figure 6 shows the potential waveform signal input to the remote control 6a, and the bottom part shows a low-frequency signal obtained by passing this potential waveform signal through the filter circuit 36a. Also, Figure 7 shows a potential waveform signal that is an enlarged portion of the potential waveform signal shown in the top part of Figure 6. The filtering process by the filter circuit 36a will be described later.

In the example shown in Fig. 6, when the bather immerses himself in the hot water in the bathtub body 2 at time _t10 , the amplitude of the potential waveform signal becomes larger. Thus, when hot water is stored in the bathtub body 2, the amplitude of the potential waveform signal becomes larger when the bather enters the bathtub body 2 than when the bather is not in the bathtub body 2. Furthermore, as shown in Fig. 7, which is an enlarged view of a portion of the waveform in the upper part of Fig. 6, when a bather is bathing in the bathtub body 2 containing hot water, the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b contains periodic pulses representing the bather's heartbeat.

In this way, in step S3 of FIG. 4, it is determined whether or not a person is bathing in the bathtub body 2 based on whether or not the potential waveform signal contains periodic pulses (electrocardiogram signals) that represent the bather's heartbeat. Specifically, for example, the frequency spectrum of the input potential waveform signal is calculated, and if there is a peak in the frequency band corresponding to the human heartbeat, it can be determined that a person is bathing in the bathtub body 2.

Next, in step S4 of FIG. 4, the input potential waveform signal is passed through the filter circuit 36a, and a low-frequency signal is extracted. That is, the potential waveform signal shown in the upper part of FIG. 6 is converted into the low-frequency signal shown in the lower part of FIG. 6 by passing it through the filter circuit 36a. In this way, by passing the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b through the filter circuit 36a, the components of the electrocardiogram signal representing the bather's heartbeat are attenuated. In the low-frequency signal obtained by passing it through the filter circuit 36a, the components of the electrocardiogram signal are attenuated, and the components representing the bather's body movements are emphasized.

Figure 8 shows an example of a potential waveform signal when a bather makes a body movement, where column (a) shows the potential waveform signal before passing through the filter circuit 36a, and column (b) shows the low-frequency signal after the potential waveform signal has passed through the filter circuit 36a.
As shown in Fig. 8, when the bather moves his/her body in the hot water in the bathtub main body 2, that is, when the bather moves, the potential waveform signal fluctuates in a relatively long period. Therefore, when the bather moves, the amplitude of the low-frequency signal in which the electrocardiogram signal components have been attenuated by the filter circuit 36a also becomes large. In the example shown in Fig. 8, the bather moves near the center of the waveform, and the amplitude of the low-frequency signal after passing through the filter circuit 36a in column (b) is also large. In this way, the bather's body movement can be detected based on the amplitude of the low-frequency signal obtained by passing the potential waveform signal through the filter circuit 36a.

Next, frequency components of a human electrocardiogram signal will be described with reference to FIGS.
Fig. 9 is a diagram showing a typical human electrocardiogram signal waveform, Fig. 10 is a diagram showing frequency bands in which each wave included in the electrocardiogram signal waveform appears, and Fig. 11 is a diagram showing an example of a low-frequency signal obtained when the cutoff frequency of the filter circuit 36a is variously changed.

First, as shown in Figure 9, a human electrocardiogram signal contains an R wave, which is an impulse-like waveform with the largest peak value on the positive side, a Q wave, which has a slight drop in potential just before the R wave, and a P wave, which has a gradual rise in potential before the Q wave. Furthermore, an electrocardiogram signal contains an S wave, which has a slight drop in potential just after the R wave, a T wave, which has a relatively large and gradual rise in potential after the S wave, and a U wave, which has a small rise in potential after the T wave. Here, it is said that the P wave corresponds to excitation of the atria of the heart, the R wave, which is an impulse-like waveform, corresponds to excitation of the ventricles, and the T wave corresponds to the cooling of ventricular excitation.

As shown in FIG. 10, the R, S, and Q waves contained in the electrocardiogram signal are distributed in a frequency band of approximately 10 Hz to 30 Hz, and the T waves are distributed in a frequency band of approximately 1 Hz to 10 Hz. Meanwhile, the inventors' research has found that changes in the potential waveform signal due to the body movements of the bather in the bathtub body 2 appear in a frequency band of approximately 2 Hz or less. The inventors' research has also found that noise generated by the bather's breathing appears in a frequency band of approximately 0.3 Hz or less. Therefore, it is believed that the components of the bather's electrocardiogram signal contained in the potential waveform signal can be attenuated by attenuating signal components in a frequency band of approximately 2 Hz or more using the filter circuit 36a.

Furthermore, as shown in FIG. 11, when the cutoff frequency of the filter circuit 36a, which is a low-pass filter, is changed to 12 Hz, 10 Hz, 8 Hz, etc., the sharp peaks are gradually reduced from the original waveform before passing through the filter circuit 36a, and the signal components representing the body movements of the bather are emphasized. As shown in FIG. 11, when the signal passes through the filter circuit 36a with a cutoff frequency of 10 Hz, the R-wave components of the electrocardiogram signal are attenuated to a certain extent from the potential waveform signal, so that the body movements of the bather can be detected by setting the cutoff frequency of the filter circuit 36a to approximately 10 Hz or less. In addition, in this embodiment, a filter circuit 36a with a cutoff frequency of 2 Hz and attenuation characteristics of -3 dB/oct is used, which sufficiently attenuates the components of the electrocardiogram signal from the potential waveform signal, making it possible to accurately detect the body movements of the bather.

As shown in FIG. 10, the frequency components of the T waves contained in the electrocardiogram signal may extend into a frequency band of 2 Hz or less, and therefore the components of the electrocardiogram signal are not completely removed even when passed through the filter circuit 36a. Also, as shown in FIG. 10, noise components due to the breathing of the bather are present in a frequency band of 0.3 Hz or less. To attenuate or remove these noise components, the present invention can be configured to apply a high-pass filter to the potential waveform signal in addition to the filter circuit 36a, as a modified example. In this case, the cutoff frequency of the high-pass filter is set to approximately 0.3 Hz, which is lower than the cutoff frequency of the filter circuit 36a.

Returning to FIG. 4, in step S5, it is determined whether the low-frequency signal extracted by the filter processing in step S4 exceeds a predetermined judgment criterion threshold. As explained in FIG. 8, when the bather moves, the potential waveform signal fluctuates over a relatively long period, so that the amplitude of the low-frequency signal after passing through the filter circuit 36a also becomes large. In step S5, the judgment circuit 36b built into the remote control 6a determines whether the low-frequency signal exceeds the judgment criterion threshold B (FIG. 8). The setting of the judgment criterion threshold B will be described later. If the low-frequency signal exceeds the judgment criterion threshold B, the process proceeds to step S9, and if it does not exceed the judgment criterion threshold B, the process proceeds to step S6.

Next, in step S6, the value of a timer (not shown) provided in the judgment circuit 36b is incremented. This timer is configured to accumulate the elapsed time after the bather's body movements are no longer detected. Meanwhile, in step S9, the accumulated timer value is reset, and one processing cycle of the flowchart shown in FIG. 4 is completed. That is, when the bather's body movements are detected (steps S5 → S9), the timer value that accumulated the time during which the bather's body movements were not detected is reset.

On the other hand, if the bather's body movement is not detected in step S5 and the timer (not shown) value is incremented in step S6, the process proceeds to step S7, where it is determined whether the elapsed time accumulated by the timer has exceeded a predetermined judgment time τ. If the elapsed time exceeds the judgment time τ, the process proceeds to step S8, and if not, the process returns to step S5. Therefore, if the state in which the bather's body movement is not detected continues, the process of steps S5 → S6 → S7 → S5 is repeated, and the elapsed time after the bather's body movement is no longer detected is accumulated. In this embodiment, the predetermined judgment time τ is set to 60 [Sec] to 180 [Sec]. That is, in this embodiment, the set value of the judgment time τ is changed while the bathtub device 1 is operating. The setting of the judgment time τ will be described later, but the judgment time τ can also be set to a fixed value.

When the elapsed time accumulated by the timer (not shown) exceeds the judgment time τ, the process in the flow chart proceeds from step S7 to S8, and in step S8, the judgment circuit 36b judges that "the bather has no body movement". That is, when the low-frequency signal does not exceed the predetermined judgment criterion threshold B within the predetermined judgment time τ, the judgment circuit 36b judges that "the bather has no body movement". Furthermore, the judgment circuit 36b sends a signal to the display unit 36c and the speaker 36d built into the remote control 6a, and displays "the bather has no body movement" on the display (not shown) of the display unit 36c and generates an alarm sound from the speaker 36d. That is, when the bather in the bathtub body 2 is in a relaxed state, there may be almost no body movement for a short period of time, and body movement may not be detected. However, even if the bather is relaxed, it is extremely rare for the state in which body movement is not detected to continue beyond the predetermined judgment time τ.

In this way, if the state where the bather's body movement is not detected continues beyond the specified judgment time τ, there is a high possibility that the bather is dozing off or has lost consciousness, and it is necessary to issue an alarm to the bather. Also, if the bather is dozing off, an alarm sound can be generated from speaker 36d to wake the bather up and encourage him or her to get out of the bath.

On the other hand, in this embodiment, if it is determined that "the bather is not moving", the determination circuit 36b also notifies a display device (not shown) located outside the bathroom R. Specifically, the display device outside the bathroom R also displays "the bather is not moving" and emits an alarm from the display device's speaker. This notifies family members outside the bathroom R that something is wrong with the bather in the bathtub body 2, so that they can take appropriate measures. In addition, to notify family members that the bather is bathing safely, it is also possible to display on the display device that the bather is moving. For example, when the bather's movement is confirmed, a lamp on the display device can be made to flash, or the number of seconds before the movement occurred can be displayed on the screen of the display device.

Next, the setting of the determination criterion threshold value for the determination circuit 36b to determine the body movement of the bather will be described with reference to FIGS.
Fig. 12 is a diagram showing an example of a change in the potential waveform signal due to a change in the bather's position in the bathtub body. Fig. 13 is a diagram showing an example of a change in the potential waveform signal due to the presence or absence of bath additives in the hot and cold water in the bathtub body. Fig. 14 is a diagram showing an example of a change in the low-frequency signal and its frequency power spectrum when the bather has and has not made any body movements. Fig. 15 is a diagram showing the relationship between the low-frequency signal and the set judgment criterion threshold B.

The amplitude of the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b changes depending on various conditions, so in the bathtub device 1 of this embodiment, the judgment criteria for determining whether or not the bather is moving is changed based on predetermined conditions. That is, the judgment criterion threshold, which is one of the judgment criteria, is changed by the judgment circuit 36b based on the potential waveform signal.

Figure 12 shows an example of the change in the potential waveform signal due to a change in the bather's position in the bathtub body 2. Here, column (a) of Figure 12 shows the potential waveform signal when the bather is away from the negative electrode 4a and positive electrode 4b provided on the bathtub body 2, column (b) shows the low-frequency signal, column (c) shows the potential waveform signal when the bather is close to the electrodes, and column (d) shows the low-frequency signal.

As can be seen from Figure 12, when the bather is away from the negative electrode 4a and the positive electrode 4b of the bathtub body 2, the amplitude of the potential waveform signal becomes smaller, and when the bather is closer to the electrodes, the amplitude of the potential waveform signal becomes larger. For this reason, when the judgment criterion threshold B is set to the same value as shown in the figure, even if the bather's body movements are the same, body movement will be detected when the bather is close to the electrodes (the oval part in column (d) of Figure 12), but will not be detected when the bather is away from the electrodes.

Next, Figure 13 shows an example of the change in the potential waveform signal when bath additives are added to the water in the bathtub body 2. Here, column (a) of Figure 13 shows the potential waveform signal when no bath additives are added, column (b) shows the corresponding low-frequency signal, column (c) shows the potential waveform signal when bath additives are added, and column (d) shows the corresponding low-frequency signal. When bath additives are added to the water in the bathtub body 2, the impedance of the water decreases, and so the amplitude of the potential waveform signal becomes smaller.

As can be seen from Fig. 13, when bath additives are added to the water in the bathtub body 2, the amplitude of the potential waveform signal is small, and when no bath additives are added, the amplitude of the potential waveform signal is large. For this reason, when the judgment criterion threshold value B is set to the same value as shown in the figure, even if the bather's body movements are the same, body movements will be detected when no bath additives are added (the oval part in column (c) of Fig. 13), but will not be detected when bath additives are added.
In this way, since the amplitude of the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b changes depending on various conditions, in the bathtub apparatus 1 of this embodiment, the judgment reference threshold value is changed based on predetermined conditions.

Next, a procedure for setting the judgment threshold value will be described with reference to FIGS.
First, in Fig. 14, (a) shows an example of a low-frequency signal when the bather is moving, (b) shows its frequency power spectrum, and (c) shows an example of a low-frequency signal when the bather is not moving, and (d) shows its frequency power spectrum.

As shown in (a) and (b) of FIG. 14, when the bather is moving, the amplitude and frequency power spectrum of the low-frequency signal obtained by filtering the potential waveform signal are relatively large. In contrast, as shown in (c) and (d) of FIG. 14, when the bather is not moving, the amplitude of the low-frequency signal is small and the value of its frequency power spectrum is also small, but the low-frequency signal is periodic, and small peaks are observed in the frequency power spectrum at approximately 0.5 Hz and approximately 1.35 Hz. The periodic signal components contained in the low-frequency signal are thought to be based on the T waves of the electrocardiogram signal that have passed through the filter circuit 36a (FIG. 10). Based on such periodic signal components contained in the low-frequency signal, the judgment criterion threshold can be set.

That is, as shown in FIG. 15, first, the judgment circuit 36b averages the peak values (circles in FIG. 15) of the low-frequency signal over a predetermined period to calculate the peak average value (dashed line in FIG. 15). Then, a value obtained by adding a predetermined margin α (fixed value) to this peak average value is set as the judgment criterion threshold value B. Furthermore, in this embodiment, the judgment criterion threshold value B is successively updated in the decreasing direction by the judgment circuit 36b based on the low-frequency signal.

For example, in the low-frequency signal shown in the lower part of FIG. 6, after the bather enters the bathtub body 2 at time _t10 , the peak values over the most recent predetermined period are averaged to calculate the peak average value. The initial judgment criterion threshold value _B1 is set by adding a predetermined margin α to this peak average value. In the example of FIG. 6, after the bather enters the bathtub body 2, the body movement of the bather gradually decreases, so the peak average value over the most recent predetermined period also gradually decreases. Therefore, the value of the judgment criterion threshold value B obtained by adding the predetermined margin α to this peak average value also gradually decreases compared to the value of the initial judgment criterion threshold value _B1 . If the newly calculated judgment criterion threshold value B is smaller than the previous judgment criterion threshold value B, the judgment criterion threshold value is updated, and the initial judgment criterion threshold value _B1 is updated to the judgment criterion threshold value _B2 . In this way, in this embodiment, the value of the judgment criterion threshold value B is updated successively over time.

Thereafter, if the bather makes a large body movement (the dashed ellipse in FIG. 6), the newly calculated peak average value also becomes larger, but if the peak average value changes in an increasing direction, the judgment criterion threshold value is not updated, and the previous judgment criterion threshold value _B2 is maintained. In this way, the judgment circuit 36b sequentially updates the judgment criterion threshold value B in a decreasing direction based on the low-frequency signal. As a result, even if bath additives have been added to the hot water in the bathtub body 2, the judgment criterion threshold value B is sequentially updated in a decreasing direction, and the value of the judgment criterion threshold value B converges to an appropriate value.

In this embodiment, the low-frequency signal obtained based on the potential waveform signal is used to sequentially update the judgment criterion threshold B in the decreasing direction, but the present invention can also be configured to change the judgment criterion threshold B based on the potential waveform signal. For example, the judgment criterion threshold B can be changed based on the peak value of the R wave of the electrocardiogram signal component contained in the potential waveform signal. Alternatively, the judgment criterion threshold B can be set to a fixed value without changing it.

Next, a change in the determination time τ, which is one of the criteria used by the determination circuit 36b, will be described with reference to FIG.
FIG. 16 is a diagram showing an example of a potential waveform signal after a bather enters the bathtub body 2.

As shown in Figure 16, after the bather enters the bathtub body 2 at time 0, for the first 350 seconds or so, there is relatively little body movement (the amplitude of the potential waveform signal is small), and then body movement increases from the middle to the end of the bath. This is thought to be because in the beginning of the bath, the bather does not move much as he or she gets used to the temperature of the water in the bathtub body 2, and after getting used to the temperature, the bather's body movement begins to increase. In other words, from the middle to the end of the bath, the body warms up and sweats more, so the bather begins to wipe it off with his or her hands and massage his or her hands to relax, and body movement increases. On the other hand, it is thought that the bather is more likely to fall asleep from the middle to the end of the bath while relaxing in the bathtub body 2.

In this embodiment, based on such a bather's behavior pattern, the judgment time τ is set long in the beginning of bathing, and is changed to a short value from the middle of bathing onwards. That is, since the bather's body movements are small in the beginning of bathing, if the judgment time τ is set short, it is easy to erroneously judge that "the bather has no body movements", and a malfunction occurs in which a warning sound is issued from the remote control 6a even though the bather is bathing normally. On the other hand, since the bather's body movements increase from the middle of bathing onwards, erroneous judgment is unlikely to occur even if the judgment time τ is set short. In addition, by setting the judgment time τ short from the middle of bathing onwards, it is easy to discover that "the bather has no body movements" at a time when the bather is likely to fall asleep, etc., and accidents in the bathroom can be more reliably prevented.

For this reason, in this embodiment, the judgment time τ is set to 180 [sec] until 300 [sec] has elapsed after the bather enters the bathtub body 2, and is changed to 60 [sec] after 300 [sec]. The judgment time τ can also be set as a fixed value. The period of the low-frequency signal is also affected by the period of the bather's body movements. For this reason, as a modified example, the present invention can be configured to change the judgment time τ based on the potential waveform signal. For example, the potential waveform signal during a normal bathing session of a bather can be learned, and the bathing time during normal bathing and the period of body movements can be recorded, and the judgment time τ can be changed based on these. In this way, by changing the judgment time τ based on the potential waveform signal, erroneous judgments based on the period of the bather's body movements can be suppressed.

According to the bathtub device 1 of the embodiment of the present invention, a potential waveform signal is acquired through the hot water stored in the bathtub main body 2, and from the acquired potential waveform signal, the component of the bather's electrocardiogram signal is attenuated by the filter circuit 36a, and a low-frequency signal is extracted. Furthermore, based on the extracted low-frequency signal, the judgment circuit 36b judges whether or not the bather is moving, so that it is possible to determine whether or not the bather is making gentle body movements in the hot water stored in the bathtub main body 2, and to accurately detect the bather's condition.

In addition, according to the bathtub apparatus 1 of this embodiment, the remote control 6a, which is an alarm device, notifies the bather inside the bathroom R that the bather is not moving, allowing the bather who has fallen into a light drowsy state to wake up on his or her own. In addition, by notifying the bather that the bather is not moving using a display device (not shown) outside the bathroom R, if the bather loses consciousness, it is possible to urge people outside the bathroom R to check on the bather's safety, making it possible to prevent drowning in the bathtub.

Furthermore, according to the bathtub device 1 of this embodiment, if the low-frequency signal does not exceed a predetermined judgment criterion threshold B within a predetermined judgment time τ, the judgment circuit 36b judges that the bather is not moving, so that it is possible to effectively distinguish between a relaxed state and a dozing state.

In addition, according to the bathtub device 1 of this embodiment, the criteria for determining whether or not the bather is moving can be changed, making it possible to accurately determine whether or not the bather is moving under various conditions.

Furthermore, according to the bathtub apparatus 1 of this embodiment, the judgment circuit 36b changes the judgment criterion threshold value B based on the potential waveform signal, so that it is possible to accurately determine whether or not the bather is moving even if the amplitude of the potential waveform signal changes overall.

In addition, according to the bathtub apparatus 1 of this embodiment, the judgment criterion threshold B is updated in a decreasing direction based on the low-frequency signal, so that the judgment criterion threshold B can be made to asymptotically correspond to the amplitude of the low-frequency signal when the bather is not moving.

Furthermore, according to the bathtub device 1 of this embodiment, the judgment time τ is changed based on the time that has elapsed since the bather entered the bathtub body 2, so that the presence or absence of the bather's body movement can be appropriately determined according to the behavior pattern.

In addition, according to the bathtub apparatus 1 of this embodiment, if it is difficult to determine whether or not the bather is moving, the remote control 6a or other alarm device will notify the bather of this in and/or outside the bathroom R. Therefore, by notifying the bather of this in the bathroom R, it is possible to alert the bather to change his/her bathing position, and by notifying the bather of this outside the bathroom R, it is possible to alert people outside the bathroom R to pay attention to the bather's condition.

In addition, in order to properly determine the presence or absence of bodily movement of the bather, the bathtub device 1 of this embodiment is equipped with a filter circuit in which the electrodes acquire the bather's electrocardiogram signal via the hot and cold water stored in the bathtub body, attenuate the components of the electrocardiogram signal, and extract a low-frequency signal from the potential waveform signal, and a determination circuit that determines the presence or absence of bodily movement of the bather based on the low-frequency signal, but the device may also be equipped with other means than the means for determining the presence or absence of bodily movement using the acquired electrocardiogram signal of the bather, and may also be equipped with means for detecting the heartbeat from the electrocardiogram signal, body temperature discrimination means for determining whether the bather's body temperature has risen or fallen based on changes in the electrocardiogram signal, etc.

The above describes an embodiment of the present invention, but various modifications can be made to the above-described embodiment.

REFERENCE SIGNS LIST 1 Bathtub device 2 Bathtub body 2a Backrest surface 4a Negative electrode 4b Positive electrode 4c Reference electrode 6 Signal processing device 6a Remote control (alarm device)
6b Housing 10 Electrode portion 10a Disk portion 10b Shaft portion 12a Front packing 12b Rear packing 14 Flange 16 Moisture-proof tube 18 Connection terminal 20 Fixing screw 22 Conductor 24 Sheath 26 Differential amplifier circuit 28 Pre-filter 30 Amplification circuit 32 A/D converter 34 Interface circuit 36a Filter circuit 36b Determination circuit 36c Display unit 36d Speaker

Claims (9)

A bathtub device equipped with a function for detecting the state of a bather,
The bathtub body,
A set of electrodes arranged below the water surface level of the water stored in the bathtub body in order to obtain a potential waveform signal through the water stored in the bathtub body;
a filter circuit for attenuating the components of the bather's electrocardiogram signal contained in the potential waveform signal acquired by the electrodes;
a determination circuit for determining whether or not a person in the bath is moving based on the signal that has passed through the filter circuit;
A bathtub apparatus comprising: The bathtub apparatus according to claim 1 further comprises an alarm device that notifies the presence or absence of body movement of the bather determined by the determination circuit to the inside of the bathroom in which the bathtub body is installed and/or to the outside of the bathroom. A bathtub apparatus as described in claim 1 or 2, wherein the judgment circuit determines that the bather is not moving if the signal after passing through the filter circuit does not exceed a predetermined judgment criterion threshold within a predetermined judgment time. The bathtub device according to claim 3, wherein the determination circuit changes the determination criterion threshold or the determination time for determining whether or not the bather is moving based on a predetermined condition. The bathtub device according to claim 4, wherein the judgment circuit changes the judgment criterion threshold value based on the potential waveform signal. 6. The bathtub apparatus according to claim 5, wherein the determination circuit successively updates the determination reference threshold in a decreasing direction based on the signal that has passed through the filter circuit . The bathtub apparatus according to any one of claims 4 to 6, wherein the judgment circuit changes the judgment time based on the potential waveform signal. The bathtub device according to any one of claims 4 to 7, wherein the determination circuit changes the determination time based on the time that has elapsed since the bather entered the bathtub body. The bathtub apparatus according to claim 2, wherein the notification device notifies the inside and/or outside of the bathroom when the determination circuit determines that it is difficult to determine the presence or absence of body movement of the bather based on the potential waveform signal.

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