Bathtub equipment

Abstract

To provide a bathtub device in which a state of a bather can be detected precisely.SOLUTION: A bathtub device (1) of the present invention includes a function for detecting a state of a bather. The bathtub device has: a bathtub body (2); a pair of electrodes (4a, 4b) for acquiring a potential waveform signal through the hot water received in this bathtub body; a filter circuit (36a) for attenuating a component of an electrocardiogram signal of the bather contained in the potential waveform signal acquired by this electrode, and taking out a low frequency signal from the potential waveform signal; and a determination circuit (36b) for determining presence or absence of the body motion of the bather on the basis of the low frequency signal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bathtub apparatus, and more particularly to a bathtub apparatus having a function for detecting the state of a bather. [Background technology]

[0002] In recent years, the number of people who have drowned 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.

[0003] 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, etc., which are exposed above the water surface of the bathtub, and the bather's body movements are detected based on the received reflected waves. If the bather does not make any body movements, it is assumed that the bather is dozing, and an alarm is sounded to prevent the bather from dozing.

[0004] Patent Document 2 (JP Patent Publication 2002-288755) describes a water heater. In this water heater, a human body sensor is attached to the wall of a bathroom, and an imaging device using an artificial retina provided in the human body sensor images human body movement in the bathroom and performs image processing. The human body sensor also includes an infrared sensor that detects the human body by detecting heat using infrared rays. When the human body sensor detects the cessation of human body movement, an alarm is issued by an alarm means.

[0005] 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 in a detection area, and determines whether a person is moving while bathing based on the detection result of the human presence sensor. If the state in which the human presence sensor determines that the person is not moving exceeds a predetermined time, a notification is issued to encourage movement. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2005-224299 A [Patent Document 2] Patent Publication No. 2002-288755 [Patent Document 3] Patent Publication No. 2020-112850 Summary of the Invention [Problem to be solved by the invention]

[0007] Thus, conventional devices for detecting the state of a bather mainly detect the body movements of the bather above the water surface, and based on this, detect whether the bather is dozing off, etc. However, the present inventors conducted extensive research into body movements during bathing and found that when the body 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 hands and feet 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.

[0008] 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.

[0009] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a bathtub apparatus that can accurately detect the condition of a person taking a bath. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems, the present invention provides a bathtub apparatus with a function for detecting the condition of a bather, and is 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 judgment circuit for determining whether or not the bather is moving based on the low-frequency signal.

[0011] 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 component 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.

[0012] As described above, when a bather is in a relaxed state (relaxed), the bather's body movements become less, making it difficult to distinguish between a state where the bather is dozing off or has a mental disorder. 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 a mental disorder, when the bather is relaxed, gentle body movements (shaking of the hands and feet) occur in the water of the bathtub. Furthermore, the gentle body movements described above are not large enough to ruffle the water in the bathtub, and it is difficult to detect them by measuring the movement of the water surface from outside the bathtub.

[0013] The inventors of the present invention discovered that the movement of a bather under the water surface of the bathtub appears as a change in the impedance of the hot and cold water stored in the bathtub body, and that this change in impedance can be detected by acquiring a potential waveform signal using a pair of electrodes. However, when the potential waveform signal is acquired via the hot and cold 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 gentle body movements.

[0014] 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 component of the bather's electrocardiogram signal from the acquired potential waveform signal is 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 to accurately detect the bather's condition. In addition, the acquired electrocardiogram signal can be used to detect the bather's heart rate from the electrocardiogram signal.

[0015] In the present invention, it is preferable that the device further comprises an alarm device which notifies the presence or absence of body movement of the bather as determined by the judgment circuit, both inside the bathroom in which the bathtub body is installed and / or outside the bathroom.

[0016] According to the present invention configured in this way, by notifying the bather inside the bathroom that there is no body movement, the bather who has fallen into a light drowsy state can be woken up by himself. In addition, by notifying the outside of the bathroom that there is no body movement, 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 the bather inside the bathroom that there is body movement, the bather can be aware that he or she is bathing safely. In addition, by notifying the outside of the bathroom that there is body movement, people outside the bathroom can be aware that the bather is bathing safely.

[0017] In the present invention, the determination circuit preferably determines that the bather is not making any body movement when the low frequency signal does not exceed a predetermined determination criterion threshold within a predetermined determination time.

[0018] A relaxed bather may continue to have no body movement detected for a short period of time even if the bather is awake. According to the present invention configured as described above, the determination circuit determines that the bather has no body movement when the low-frequency signal does not exceed a predetermined determination criterion threshold within a predetermined determination time, so that a relaxed state and a dozing state can be effectively distinguished.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] In the present invention, when the judgment 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 alarm device preferably issues a notification to that effect inside and / or outside the bathroom.

[0025] The potential waveform signal may not be able to be adequately detected, for example, when the position or posture of the bather 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. According to the present invention configured as described above, when it is difficult to determine whether the bather is moving, the bather can be alerted to this fact within the bathroom, for example by encouraging the bather to change his / her bathing position, and the bather can be alerted to this fact outside the bathroom, for example by encouraging people outside the bathroom to pay attention to the bather's condition. Effect of the Invention

[0026] According to the bathtub apparatus of the present invention, the condition of a bather can be detected accurately. [Brief description of the drawings]

[0027] [Figure 1] 1 is a perspective view showing an entire bathroom in which a bathtub apparatus according to an embodiment of the present invention is installed. [Diagram 2] 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. [Diagram 3] 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. [Figure 4] 4 is a flowchart showing the operation of a bathtub apparatus according to an embodiment of the present invention. [Diagram 5] 11 is a potential waveform signal showing an example of a state in which the body movement of a bather cannot be detected normally. [Figure 6] 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. [Figure 7] 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. [Figure 8] FIG. 13 is a diagram showing an example of a potential waveform signal when a bather makes a body movement. [Figure 9] FIG. 1 is a diagram showing a typical human electrocardiogram signal waveform. [Figure 10]FIG. 2 is a diagram showing frequency bands in which each wave included in an electrocardiogram signal waveform appears. [Figure 11] 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. [Figure 12] 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. [Figure 13] 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. [Figure 14] 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. [Figure 15] FIG. 11 is a diagram showing the relationship between a low-frequency signal and a set judgment criterion threshold value. [Figure 16] 13 is a diagram showing an example of a potential waveform signal after a bather enters the bathtub body. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 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 a 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 a bathtub apparatus according to an embodiment of the present invention.

[0029] As shown in Figure 1, a bathtub apparatus 1 according to an embodiment of the present invention comprises a bathtub main body 2, a negative electrode 4a, a positive electrode 4b, and a reference electrode 4c attached to the bathtub main 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.

[0030] 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 constituting 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 detachably attached to the long side of the bathtub body 2 that is not in contact with the inner wall surface of the bathroom R.

[0031] 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 the negative electrode 4a and the 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. In this way, in the bathtub device 1 of this embodiment, all of the electrodes for obtaining an electrocardiogram signal are arranged on one backrest surface 2a.

[0032] The negative electrode 4a and the positive electrode 4b are arranged on the left and right of the center line in the horizontal direction (width direction) of the backrest surface 2a, at 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, spaced apart from each other in the left and right direction from the center line. 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 the negative electrode 4a and the positive electrode 4b may be arranged.

[0033] 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.

[0034] 2, the negative electrode 4a has an electrode part 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.

[0035] The electrode unit 10 is a conductive metal part, and is composed of a disk part 10a formed in a disk shape and a shaft part 10b protruding perpendicularly from the back of the disk part 10a. The disk part 10a is a thin disk-shaped part, and the front surface of the disk part 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 part 10a is formed to have a diameter of about 15 mm and a thickness of about 2.5 mm, and the entire disk part 10a is disposed on the surface of the backrest surface 2a. The shaft part 10b is a round bar-shaped part extending at a right angle from the center of the back of the disk part 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 part 10b, and a fixing part for fixing the connection terminal 18 is formed at the tip part.

[0036] 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. 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.

[0037] 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. 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 disposed 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.

[0038] The flange 14 is a stepped cylindrical member consisting of a large diameter portion and a small diameter portion, and has a female screw thread formed in the center for passing the shaft portion 10b of the electrode portion 10 through it. 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 screw thread formed to pass through the flange 14 and the male screw thread formed on the shaft portion 10b of the electrode portion 10, the end face of the flange 14 on the large diameter portion side presses the back gasket 12b against the back of the backrest surface 2a, ensuring watertightness.

[0039] The moisture-proof tube 16 is a long, thin tube made of rubber, and 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.

[0040] The connection terminal 18 is a component made of conductive metal, and is crimped and connected to the tip of the conductor 22. A hole for passing a fixing screw 20 is provided at the tip of the connection terminal 18, and the fixing screw 20 passing through this hole can be screwed into a female screw provided at the tip of the shaft portion 10b of the electrode portion 10, thereby fixing the connection terminal 18 to the electrode portion 10. This allows the electrode portion 10 and the conductor 22 to be electrically connected in a detachable manner.

[0041] The conductor 22 is a conductive wire for electrically connecting the electrode unit 10 and a signal processing device 6 (FIG. 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 an electrocardiogram signal is input to the signal processing device 6.

[0042] 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 informing device that informs the bather that there is no body movement.

[0043] 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.

[0044] 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 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.

[0045] The remote controller 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 equipment 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 configured by a microprocessor and memory built into the remote controller 6a, and software for operating them. As a modified example, the present invention can also be configured so that the filter circuit and the judgment circuit are configured by hardware circuits and the low-frequency signal is extracted by an analog filter to perform judgment.

[0046] 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 determination circuit 36b determines whether the bather is moving based on the low-frequency signal, and if it is determined that the bather is not moving, a message indicating that the bather is not moving is displayed on the display unit 36c and a warning sound is generated from the speaker 36d. The communication unit 36e also transmits a control signal to a display device (not shown) arranged outside the bathroom R, which displays a message indicating that the bather is not moving and generates 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 determination circuit 36b are built into a display device (not shown) outside the bathroom R. The communication unit 36e is also configured to transmit 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 a signal to a smartphone of the person taking a bath or a family member to notify them of the condition of the person taking a bath.

[0047] 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, maintenance such as adjustment and repair of each electrode and the signal processing device 6 can be easily performed simply by removing the apron 2b of the bathtub body 2. In other words, by collectively arranging the negative electrode 4a, the positive electrode 4b, the reference electrode 4c, and the signal processing device 6 in an easily accessible space, maintainability can be improved.

[0048] 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 flowchart showing the operation of the bathtub apparatus 1 according to the embodiment of the present invention. Figs. 5 to 16 are diagrams for explaining the processing in the flowchart of Fig. 4.

[0049] The flowchart shown in FIG. 4 is repeatedly executed at predetermined time intervals by a microprocessor built into the remote control 6a while the bathtub apparatus 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.

[0050] Next, in step S2, it is determined whether the bather's body movement can be detected normally. If the body movement can be detected normally, the process proceeds to step S3. If the body movement cannot be detected normally, the process proceeds to step S10. That is, the body movement of the bather is detected based on a 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 movement of the bather cannot be detected, so in step S10, a notice to that effect is given, 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.

[0051] FIG. 5 is 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) becomes 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.

[0052] Next, in step S3 in FIG. 4, it is determined whether or not 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 one round of processing in 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. That is, when the bather is bathing near the backrest surface 2a of the bathtub body 2, the component of the bather's electrocardiogram signal is 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.

[0053] In step S3, it is determined whether or not a bather is in the bathtub body 2 depending 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 round of processing in the flowchart shown in Figure 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.

[0054] Fig. 6 is a diagram showing an example of a potential waveform signal before and after a bather is immersed in the hot water in the bathtub main body 2. The upper part of Fig. 6 shows the potential waveform signal input to the remote control 6a, and the lower part shows a low-frequency signal obtained by passing this potential waveform signal through the filter circuit 36a. Fig. 7 is a diagram showing an enlarged potential waveform signal of a part of the potential waveform signal shown in the upper part of Fig. 6. The filtering process by the filter circuit 36a will be described later.

[0055] In the example shown in FIG. 10In FIG. 6, when a bather is immersed in the hot water in the bathtub body 2, the amplitude of the potential waveform signal becomes larger. Thus, when hot water is stored in the bathtub body 2, when a bather enters the bathtub body 2, the amplitude of the potential waveform signal becomes larger 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.

[0056] 4, whether or not a person is bathing in bathtub main body 2 is determined based on whether or not the potential waveform signal contains periodic pulses (electrocardiogram signals) representing 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 bathtub main body 2.

[0057] 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 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 component of the electrocardiogram signal representing the bather's pulsation is attenuated. In the low-frequency signal obtained by passing through the filter circuit 36a, the component of the electrocardiogram signal is attenuated, and the component representing the bather's body movement is emphasized.

[0058] 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.

[0059] Next, the 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 waves included in an electrocardiogram signal waveform appear. 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.

[0060] First, as shown in Figure 9, a human electrocardiogram signal includes 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 includes 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 the excitation of the atrium of the heart, the R wave, which is an impulse-like waveform, corresponds to the excitation of the ventricles, and the T wave corresponds to the cooling of the excitation of the ventricles.

[0061] As shown in Fig. 10, the R-wave, S-wave, and Q-wave contained in the electrocardiogram signal are distributed in a frequency band of about 10 Hz to 30 Hz, and the T-wave is distributed in a frequency band of about 1 Hz to 10 Hz. Meanwhile, the inventors have found through their research that the change in the potential waveform signal caused by the body movement of the bather in the bathtub body 2 appears in a frequency band of about 2 Hz or less. The inventors have also found through their research that the noise generated by the bather's breathing appears in a frequency band of about 0.3 Hz or less. Therefore, it is considered that the components of the bather's electrocardiogram signal contained in the potential waveform signal can be attenuated by attenuating the signal components in a frequency band of about 2 Hz or more using the filter circuit 36a.

[0062] 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, ..., 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 about 10 Hz or less. In addition, in this embodiment, a filter circuit 36a with a cutoff frequency of 2 Hz and attenuation characteristic 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.

[0063] As shown in Fig. 10, the frequency components of the T waves contained in the electrocardiogram signal may extend to a frequency band of 2 Hz or less, so that the components of the electrocardiogram signal are not completely removed even when the signal passes 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. In order to attenuate or remove these noise components, the present invention can be modified so that a high-pass filter is applied to the potential waveform signal in addition to the filter circuit 36a. In this case, the cutoff frequency of the high-pass filter is set to about 0.3 Hz, which is lower than the cutoff frequency of the filter circuit 36a.

[0064] Returning to FIG. 4, in step S5, it is determined whether or not 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 in a relatively long cycle, 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 in the remote control 6a determines whether or not 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.

[0065] 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.

[0066] On the other hand, if the body movement of the bather is not detected in step S5 and the value of the timer (not shown) is incremented in step S6, the process proceeds to step S7, where it is determined whether the elapsed time accumulated by the timer exceeds 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 body movement of the bather is not detected continues, the process of steps S5 → S6 → S7 → S5 is repeated, and the elapsed time after the body movement of the bather 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 during the operation of the bathtub equipment 1. The setting of the judgment time τ will be described later, but the judgment time τ can also be set as a fixed value.

[0067] 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 main 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 that the state in which body movement is not detected continues beyond the predetermined judgment time τ.

[0068] In this way, if the state where the body movement of the bather is not detected continues beyond the predetermined judgment time τ, it is highly likely that the bather is dozing off or has lost consciousness, and it is necessary to issue an alarm to the bather, etc. Also, if the bather is dozing off, an alarm sound can be generated from the speaker 36d to wake the bather up and encourage him or her to get out of the bath.

[0069] On the other hand, in this embodiment, when it is determined that "the bather has no body movement," the determination circuit 36b also notifies a display device (not shown) arranged outside the bathroom R. Specifically, the display device outside the bathroom R also displays "the bather has no body movement" on its display, and an alarm sound is emitted from the speaker of the display device. This notifies family members outside the bathroom R that something is wrong with the bather in the bathtub body 2, so that the family members can take appropriate measures. In addition, to notify that the bather is bathing safely, it is also possible to display on the display device that the bather has body movement. For example, when the bather's body movement is confirmed, the lamp of the display device can be made to flash, or the number of seconds before the body movement was made can be displayed on the screen of the display device.

[0070] 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 is and is not moving. Fig. 15 is a diagram showing the relationship between the low-frequency signal and the set judgment criterion threshold B.

[0071] Since the amplitude of the potential waveform signal acquired by the negative electrode 4a and the positive electrode 4b varies depending on various conditions, the criterion for determining the presence or absence of body movement of the bather is changed based on predetermined conditions in the bathtub apparatus 1 of this embodiment. That is, the criterion threshold, which is one of the criteria, is changed by the judgment circuit 36b based on the potential waveform signal.

[0072] Fig. 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, in Fig. 12, column (a) 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 corresponding low-frequency signal, column (c) shows the potential waveform signal when the bather is close to the electrodes, and column (d) shows the corresponding low-frequency signal.

[0073] As can be seen from Fig. 12, the amplitude of the potential waveform signal is smaller when the bather is far from the negative electrode 4a and the positive electrode 4b of the bathtub body 2, and the amplitude of the potential waveform signal is larger when the bather is close to the electrodes. 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 of the same magnitude, body movement will be detected when the bather is close to the electrodes (the oval part in column (d) of Fig. 12), but will not be detected when the bather is far from the electrodes.

[0074] Next, Fig. 13 shows an example of the change in the potential waveform signal when bath additives are added to the water in the bathtub main body 2. Here, in Fig. 13, column (a) 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 main body 2, the impedance of the water decreases, and so the amplitude of the potential waveform signal becomes smaller.

[0075] 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 B value is set to the same as shown in the figure, even if the bather's body movements are about the same, body movement will be detected when no bath additives are added (the oval 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 the present embodiment, the determination reference threshold value is changed based on predetermined conditions.

[0076] Next, a procedure for setting the judgment criterion threshold will be described with reference to FIGS. First, Fig. 14 (a) shows an example of a low-frequency signal when the bather is moving, and (b) shows its frequency power spectrum. Fig. 14 (c) shows an example of a low-frequency signal when the bather is not moving, and (d) shows its frequency power spectrum.

[0077] 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 considered 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.

[0078] 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.

[0079] For example, in the low-frequency signal shown in the lower part of FIG. 10 After the bather enters the bathtub body 2, 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.

[0080] 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 salts have been added to the 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.

[0081] 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 included in the potential waveform signal. Alternatively, the judgment criterion threshold B can be set to a fixed value without being changed.

[0082] 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 bathtub body 2. In FIG.

[0083] As shown in Fig. 16, after the bather enters the bathtub body 2 at time 0, for the first 350 seconds or so, the bather's body movements are relatively small (the amplitude of the potential waveform signal is small), and then the body movements increase 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 to get used to the temperature of the water in the bathtub body 2, and after getting used to the temperature, the bather's body movements start to increase. That is, 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 hands and massage his hands to relax, and body movements increase. 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.

[0084] In this embodiment, based on such a behavior pattern of the bather, 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 movement is 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 movement", 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 movement increases 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 movement" at a time when the bather is likely to fall asleep, etc., and accidents in the bathroom can be more reliably prevented.

[0085] 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 movement. 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 of a bather can be learned, and the bathing time during normal bathing and the period of body movement 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 judgment based on the period of the bather's body movement can be suppressed.

[0086] According to the bathtub apparatus 1 of the embodiment of the present invention, a potential waveform signal is acquired through the hot and cold 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 to extract a low-frequency signal. Furthermore, based on the extracted low-frequency signal, the determination circuit 36b 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 and cold water stored in the bathtub main body 2, and to accurately detect the bather's condition.

[0087] Furthermore, according to the bathtub apparatus 1 of this embodiment, the remote control 6a, which serves as an alarm device, notifies the bather inside the bathroom R that there is no body movement, allowing a bather who has fallen into a light drowsy state to wake up on his or her own. Also, by notifying the bather that there is no body movement 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.

[0088] Furthermore, according to the bathtub apparatus 1 of this embodiment, the judgment circuit 36b judges that the bather is not moving if the low-frequency signal does not exceed a predetermined judgment criterion threshold B within a predetermined judgment time τ, thereby making it possible to effectively distinguish between a relaxed state and a dozing state.

[0089] Furthermore, according to the bathtub apparatus 1 of this embodiment, the criteria for determining 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 determined under various conditions.

[0090] Furthermore, according to the bathtub apparatus 1 of this embodiment, the judgment circuit 36b changes the judgment criterion threshold 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.

[0091] 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.

[0092] Furthermore, according to the bathtub apparatus 1 of this embodiment, the judgment time τ is changed based on the elapsed time after the bather enters the bathtub body 2, so that the presence or absence of body movement of the bather can be appropriately determined according to the behavior pattern.

[0093] Furthermore, according to the bathtub apparatus 1 of this embodiment, when it is difficult to determine whether or not the bather is moving, the remote control 6a or the like, which serves as an alarm device, will notify the user of this fact inside and / or outside the bathroom R. Therefore, by notifying the user of this fact inside the bathroom R, it is possible to alert the bather to change his / her bathing position, for example, and by notifying the user of this fact outside the bathroom R, it is possible to alert people outside the bathroom R to pay attention to the bather's condition.

[0094] In addition, in order to properly determine the presence or absence of bodily movement of the bathtub user, the bathtub apparatus 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 which determines the presence or absence of bodily movement of the bather based on the low-frequency signal; however, the bathtub apparatus 1 may 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 a means for detecting the heart rate from the electrocardiogram signal, or a body temperature discrimination means for determining whether the bather's body temperature has risen or fallen based on changes in the electrocardiogram signal.

[0095] Although the embodiment of the present invention has been described above, various modifications can be made to the above-described embodiment. [Explanation of symbols]

[0096] 1 Bathtub equipment 2 Bathtub body 2a Backrest 4a negative electrode 4b Positive electrode 4c reference electrode 6 Signal Processing Device 6a Remote control (alarm device) 6b Case 10 Electrode section 10a Disc section 10b Shaft 12a Front gasket 12b Rear gasket 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 Judgment circuit 36c Display section 36d Speaker

Claims

1. 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:

2. The bathtub apparatus of claim 1 further comprises an alarm device which notifies the presence or absence of body movement of the bather determined by the judgment circuit to the bathroom in which the bathtub body is installed and / or outside the bathroom.

3. 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.

4. 4. The bathtub apparatus according to claim 3, wherein the determination circuit changes the determination criterion threshold value or the determination time for determining whether or not the bather is moving, based on a predetermined condition.

5. 5. The bathtub apparatus according to claim 4, wherein the determination circuit changes the determination reference threshold value based on the potential waveform signal.

6. 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.

7. 7. The bathtub apparatus according to claim 4, wherein the determination circuit changes the determination time based on the potential waveform signal.

8. 8. The bathtub apparatus according to claim 4, wherein the determination circuit changes the determination time based on the elapsed time after the bather enters the bathtub body.

9. The bathtub apparatus of claim 2, wherein the alarm device notifies people inside and / or outside the bathroom when the judgment circuit determines that it is difficult to determine the presence or absence of bodily movement of the bather based on the potential waveform signal.

Images