Toilet seat device and signal processing method

Abstract

To provide a toilet device which can enhance measurement quality of an electrocardiogram signal.SOLUTION: A toilet device 10 includes: an electrocardiogram signal measurement circuit 33 which measures an electrocardiogram signal based on a first signal output from a first preamplifier PA1 electrically connected to a first electrode 26L capacitively coupled with a left thigh part of a person sitting on a toilet seat body 21 and a second signal output from a second preamplifier PA2 electrically connected to a second electrode 26R capacitively coupled with a right thigh part of the person sitting on the toilet seat body 21; a body ground electrode 22 making contact with the person sitting on the toilet seat body 21; and a body ground potential generating circuit 37 which generates a body ground potential by performing processing of inverting polarities of an AC component of the second signal on the second signal and applies the generated body ground potential on the person through the body ground electrode 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a toilet seat device having a function for measuring electrocardiogram signals. [Background technology]

[0002] Various techniques for measuring a person's electrocardiogram signal are known. Patent Document 1 discloses an electrocardiogram measuring device capable of accurately measuring electrocardiograms. Patent Document 2 discloses a technique for detecting the cardiac potential of a seat occupant with high sensitivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-047135 [Patent Document 2] Japanese Patent Application Publication No. 2019-092845 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention provides a toilet seat device and the like that can improve the measurement quality of electrocardiogram signals. [Means for solving the problem]

[0005] A toilet seat device according to one embodiment of the present invention comprises a first electrode arranged on the underside or inside of the toilet seat body, the first electrode being capacitively coupled to the left thigh of a person sitting on the toilet seat body; a first amplifier electrically connected to the first electrode; a second electrode arranged on the underside or inside of the toilet seat body, the second electrode being capacitively coupled to the right thigh of the person sitting on the toilet seat body; a second amplifier electrically connected to the second electrode; an electrocardiogram signal measurement circuit that measures an electrocardiogram signal based on a first signal output from the first amplifier and a second signal output from the second amplifier; a body earth electrode, at least a portion of which is exposed to the outside from the front side of the toilet seat body and comes into contact with the person sitting on the toilet seat body; and a body earth potential generation circuit that generates a body earth potential by processing the second signal to invert the polarity of the AC (Alternating Current) component of the second signal, and applies the generated body earth potential to the person via the body earth electrode.

[0006] A signal processing method according to one aspect of the present invention is a signal processing method executed by an information terminal connected to the toilet seat device, and includes an acquisition step of acquiring the electrocardiogram signal measured by the toilet seat device, an analysis step of analyzing the acquired electrocardiogram signal, and a display step of displaying the results of the analysis.

[0007] A program according to one aspect of the present invention is a program for causing a computer to execute the signal processing method. [Effects of the Invention]

[0008] The toilet seat device etc. of the present invention can improve the measurement quality of electrocardiogram signals. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a measurement system according to an embodiment. [Figure 2] FIG. 2 is an external view of the toilet seat device according to the embodiment. [Figure 3]FIG. 3 is a diagram for explaining capacitive coupling between the left thigh of a person sitting on the toilet seat body and the first electrode. [Figure 4] FIG. 4 is a block diagram showing the functional configuration of the information terminal. [Figure 5] FIG. 5 is a sequence diagram of a first operation example of the measurement system according to the embodiment. [Figure 6] FIG. 6 is a diagram showing an example of the waveform of an electrocardiogram signal acquired at the thigh. [Figure 7] FIG. 7 is a diagram showing an example of display of an electrocardiogram signal and an RR interval (heart rate) on the display unit of an information terminal. [Figure 8] FIG. 8 is a diagram showing the circuit configuration of a toilet seat apparatus according to the first modification. [Figure 9] FIG. 9 is a diagram showing the circuit configuration of a toilet seat apparatus according to the second modification. [Figure 10] FIG. 10 is a diagram showing an example of a waveform of an electrocardiogram signal mixed with voltage noise. [Figure 11] FIG. 11 is a sequence diagram of a second operation example of the measurement system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection forms, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0011] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0012] (Embodiment) [Measurement system configuration] A measurement system according to an embodiment will be described below. FIG. 1 is a diagram showing the configuration of a measurement system according to an embodiment. As shown in FIG. 1, the measurement system 100 includes a toilet seat device 10 and an information terminal 40. The measurement system 100 is a system that measures the electrocardiogram signal (ECG signal) of a person sitting on the toilet seat device 10, and is capable of displaying the measured electrocardiogram signal and an analysis result of the electrocardiogram signal on the information terminal 40. A person using the toilet seat device 10 can have their electrocardiogram signal measured unconsciously just by sitting on the toilet seat 20. Here, the electrocardiogram signal refers to an electrical signal from the heart.

[0013] [Configuration of toilet seat device: toilet seat] First, the toilet seat device 10 will be described with reference to Fig. 2 in addition to Fig. 1. Fig. 2 is an external view of the toilet seat device 10. As shown in Figs. 1 and 2, the toilet seat device 10 includes a toilet seat 20 and an electrocardiogram measurement module 30. The toilet seat device 10 may be a device that is attached to an existing toilet bowl by replacing the toilet seat attached to the existing toilet bowl, or may be a device that is formed integrally with the toilet bowl.

[0014] The toilet seat 20 is the part of the toilet seat device 10 on which a person sits when relieving themselves. The toilet seat 20 includes a toilet seat body 21, a first active electrode 22L, a first connection wiring 23L, a second active electrode 22R, a second connection wiring 23R, a body earth electrode 22, a third connection wiring 23, a seating sensor 24, and a plurality of leg rubbers 25.

[0015] The toilet seat body 21 is a member made of a white resin material, and also functions as a holding member that holds the other components that make up the toilet seat 20. A first active electrode 22L, a second active electrode 22R, a seating sensor 24, and a plurality of leg rubbers 25 are provided on the back surface of the toilet seat body 21. A first connection wire 23L, a second connection wire 23R, a body earth electrode 22, and a third connection wire 23 are provided inside the toilet seat body 21.

[0016] The first active electrode 22L is a substrate module in which a first electrode 26L is provided on one main surface of a first substrate (not shown) and a first preamplifier PA1 is provided on the other main surface of the first substrate. More specifically, the first active electrode 22L includes the first electrode 26L, the first preamplifier PA1, a first wiring 27L, and a first resistor R1.

[0017] The first electrode 26L is a plate-shaped (thin film) electrode provided on the back surface of the toilet seat body 21, and functions as a measurement electrode for measuring electrocardiogram signals. Specifically, the first electrode 26L is formed from a metal material with low resistivity, such as copper foil. The first electrode 26L is an electrode that capacitively couples with the left thigh of a person sitting on the toilet seat body 21 (hereinafter also referred to as the left thigh). In other words, the first electrode 26L functions as a capacitive electrode. Figure 3 is a diagram for explaining the capacitive coupling between the left thigh of a person sitting on the toilet seat body 21 and the first electrode 26L.

[0018] As shown in FIG. 3, the first electrode 26L is provided on the back side of the toilet seat body 21 at a position where the left thigh of a person sitting on the toilet seat body 21 would be located, and forms a capacitance with the left thigh, using a portion of the toilet seat body 21 (the portion surrounded by a dashed line in FIG. 3) as a dielectric. The first electrode 26L is not in direct contact with the left thigh but is electrically capacitively coupled to the left thigh. This capacitance is, for example, 100 pF or more, and the first electrode 26L can pass signals in a frequency band of at least 0.1 Hz to 30 Hz. To maintain this capacitance, the first electrode 26L is formed in close contact with the back side of the toilet seat body 21 so that no air gets between it and the toilet seat body 21. The thickness of the portion of the toilet seat body 21 located between the first electrode 26L and the left thigh is, for example, 2 mm or less (more preferably 1.5 mm).

[0019] The shape of the first electrode 26L in a plan view is, for example, rectangular, but may also be circular or elliptical. The area of ​​the first electrode 26L in a plan view is appropriately set to achieve the above-mentioned capacitance. The area of ​​the first electrode 26L in a plan view is, for example, 10,000 mm 2(10 cm×10 cm) or more. When fixing the first electrode 26L to the toilet seat body 21, one or more holes may be made inside the first electrode 26L.

[0020] The first electrode 26L only needs to be attached to the toilet seat body 21 so that a part (resin material) of the toilet seat body 21 is interposed between the first electrode 26L and the left thigh, and may be provided inside the toilet seat body 21, for example.

[0021] The first preamplifier PA1 is an example of a first amplifier, and is an amplifier to which the first biological signal obtained through the first electrode 26L is input. As the first preamplifier PA1, an operational amplifier is used that has an input impedance of 1 GΩ or more at a frequency of 10 Hz and an input noise of 2 μVp-p or less in the frequency band of 0.1 Hz to 30 Hz.

[0022] The positive input terminal of the first preamplifier PA1 is electrically connected to the first electrode 26L by the first wiring 27L, and the negative input terminal of the first preamplifier PA1 is electrically connected to the output terminal of the first preamplifier PA1. The gain of the first preamplifier PA1 is as close to 1 as possible, and the first preamplifier PA1 performs impedance conversion without voltage amplification. The output impedance at a frequency of 10 Hz is, for example, about 5 kΩ.

[0023] The first preamplifier PA1 may perform voltage amplification. Even in this case, it is desirable that the input-equivalent noise (input noise) in the frequency band of 0.1 Hz to 30 Hz be 2 μVp-p or less. The first preamplifier PA1 may be configured as a chopper amplifier circuit (not shown).

[0024] A chopper amplifier circuit (in other words, a chopper stabilization circuit) reduces the effects of 1 / f noise (flicker noise) that is mixed in during the process of taking and amplifying (differentially amplifying) the difference between the voltage at the positive input terminal and the voltage at the negative input terminal in the input stage of the first preamplifier PA1, and suppresses the input noise to the level of thermal noise (for example, 2 μVp-p or less). The first preamplifier PA1 is configured as a chopper amplifier circuit by providing chopper circuits in both the input stage and output stage of the first preamplifier PA1.

[0025] A chopper circuit provided in the input stage converts (modulates) the signal input to the first preamplifier PA1 to a frequency band of 2 kHz (2000.1 Hz to 2030 Hz) by switching, at a predetermined frequency (e.g., 2 kHz), between the positive and negative input terminals being connected normally (as is) and cross-connected (the positive and negative input terminals are swapped). The modulated signal is differentially amplified in the input stage of the first preamplifier PA1. A chopper circuit provided in the output stage of the first preamplifier PA1 demodulates (returns) the frequency band of the signal output from the first preamplifier PA1 from 2 kHz (2000.1 Hz to 2030 Hz) back to the original frequency band of 0.1 Hz to 30 Hz, and then transmits the signal to the first connection wiring 23L.

[0026] The input impedance of the first preamplifier PA1 configured as a chopper amplifier circuit is defined when the chopper circuits provided in the input and output stages of the first preamplifier PA1 are operated at a predetermined frequency. It is desirable that the first preamplifier PA1 configured as a chopper amplifier circuit have an input impedance of 1 GΩ or more at a frequency of 10 Hz.

[0027] In this specification, the terms "amplifier," "op-amp," "amplifying circuit," or "amplifier" are used not only to refer to amplifiers (amplifiers), operational amplifiers (operational amplifiers), and operational amplifier circuits (amplifying circuits) that have a voltage amplification factor greater than 1, but also to amplifiers, operational amplifiers, and operational amplifier circuits that have a voltage amplification factor of 1 or less.

[0028] The first wiring 27L electrically connects the first electrode 26L and the positive input terminal of the first preamplifier PA1. The first wiring 27L is, for example, a pattern wiring provided on the first substrate, but may also be a lead wire or the like, and its length is preferably 10 mm or less. At least a portion of the first wiring 27L is covered by an electromagnetic shield. The electromagnetic shield serves to block electric field noise, such as wireless noise, propagating through the air. The core wire of the electromagnetic shield is formed by metal wiring electrically connected to earth potential (0 V).

[0029] The first wiring 27L is electrically connected to an analog ground potential (more specifically, an output terminal of an analog ground potential generating circuit 38; the same applies below) via a first resistor element R1. The first resistor element R1 is a resistor element provided on the first substrate and has a resistance value of 10 GΩ or more. The first resistor element R1 is, for example, a chip-type resistor element, but may also be a resistor element with lead wires.

[0030] The first active electrode 22L described above is electrically connected to the electrocardiogram measurement module 30 by the first connection wiring 23L. The first connection wiring 23L is, for example, a lead wire provided inside the toilet seat body 21, and at least a portion of the lead wire is covered by an electromagnetic shield. The core wire of the electromagnetic shield is formed by metal wiring electrically connected to the earth potential.

[0031] The second active electrode 22R is a substrate module in which a second electrode 26R is provided on one main surface of a second substrate (not shown) and a second preamplifier PA2 is provided on the other main surface of the second substrate. More specifically, the second active electrode 22R includes the second electrode 26R, the second preamplifier PA2, a second wiring 27R, and a second resistor element R2.

[0032] The second electrode 26R is a plate-shaped (thin film) electrode provided on the rear surface of the toilet seat body 21, and functions as a reference electrode for measuring electrocardiogram signals. Specifically, the second electrode 26R is formed from a metal material with low resistivity, such as copper foil. The second electrode 26R is an electrode that capacitively couples with the right thigh of a person sitting on the toilet seat body 21 (hereinafter also referred to as the right thigh). In other words, the second electrode 26R functions as a capacitive electrode.

[0033] The second electrode 26R is provided on the back side of the toilet seat body 21 at a portion where the right thigh of a person sitting on the toilet seat body 21 would be located, and forms a capacitance with the right thigh, using part of the toilet seat body 21 as a dielectric. The second electrode 26R is electrically capacitively coupled to the right thigh without directly contacting the right thigh. This capacitance is, for example, 100 pF or more, and the second electrode 26R can pass signals in a frequency band of at least 0.1 Hz to 30 Hz. To maintain this capacitance, the second electrode 26R is formed in close contact with the back side of the toilet seat body 21 so that no air gets between it and the toilet seat body 21. The thickness of the portion of the toilet seat body 21 located between the second electrode 26R and the right thigh is, for example, 2 mm or less (more preferably 1.5 mm).

[0034] The shape of the second electrode 26R in a plan view is, for example, rectangular, but may also be circular or elliptical. The area of ​​the second electrode 26R in a plan view is appropriately set to achieve the above-mentioned capacitance. The area of ​​the second electrode 26R in a plan view is, for example, 10,000 mm 2 (10 cm x 10 cm) or more. When fixing the second electrode 26R to the toilet seat body 21, one or more holes may be made inside the second electrode 26R.

[0035] The second electrode 26R only needs to be attached to the toilet seat body 21 so that a part (resin material) of the toilet seat body 21 is interposed between the second electrode 26R and the right thigh, and may be provided inside the toilet seat body 21, for example.

[0036] The second preamplifier PA2 is an example of a second amplifier, and is an amplifier to which the second biological signal obtained through the second electrode 26R is input. As the second preamplifier PA2, an operational amplifier is used that has an input impedance of 1 GΩ or more at a frequency of 10 Hz and an input noise of 2 μVp-p or less in the frequency band of 0.1 Hz to 30 Hz.

[0037] The positive input terminal of the second preamplifier PA2 is electrically connected to the second electrode 26R by the second wiring 27R, and the negative input terminal of the second preamplifier PA2 is electrically connected to the output terminal of the second preamplifier PA2. The gain of the second preamplifier PA2 is as close to 1 as possible, and the second preamplifier PA2 performs impedance conversion without voltage amplification. The output impedance at a frequency of 10 Hz is, for example, about 5 kΩ.

[0038] The second preamplifier PA2 may perform voltage amplification. Even in this case, it is desirable that the input-equivalent noise (input noise) in the frequency band of 0.1 Hz to 30 Hz be 2 μVp-p or less. The second preamplifier PA2 may be configured as a chopper amplifier circuit (not shown).

[0039] It is desirable that the amplification factors of the first preamplifier PA1 and the second preamplifier PA2 have high accuracy (for example, ±0.1%).

[0040] The second wiring 27R electrically connects the second electrode 26R and the positive input terminal of the second preamplifier PA2. The second wiring 27R is, for example, a pattern wiring provided on the second substrate, but may also be a lead wire, etc., and its length is preferably 10 mm or less. At least a portion of the second wiring 27R is covered by an electromagnetic shield. The electromagnetic shield serves to block electric field noise, such as radio noise, propagating through the air. The core of the electromagnetic shield is formed by metal wiring electrically connected to earth potential.

[0041] The second wiring 27R is electrically connected to the analog ground potential via a second resistor R2. The second resistor R2 is a resistor provided on the second substrate and has a resistance value of 10 GΩ or more. The second resistor R2 is, for example, a chip-type resistor, but may also be a resistor with leads.

[0042] The second active electrode 22R described above is electrically connected to the electrocardiogram measurement module 30 by the second connection wiring 23R. The second connection wiring 23R is, for example, a lead wire provided inside the toilet seat body 21, and at least a portion of the lead wire is covered by an electromagnetic shield. The core wire of the electromagnetic shield is formed by metal wiring electrically connected to the earth potential.

[0043] The body earth electrode 22 is an electrode for applying the body earth potential generated by the body earth potential generating circuit 37 to a person sitting on the toilet seat main body 21. At least a portion of the body earth electrode 22 is exposed from the front side of the toilet seat main body 21 and comes into contact with the right thigh of a person sitting on the toilet seat main body 21. The body earth electrode 22 is formed from a metal material such as copper.

[0044] For example, the body earth electrode 22 is provided in a position where it partially or entirely overlaps the leg rubber 25 in a plan view. This allows the body earth electrode 22 to be pressed against the right thigh of a person sitting on the toilet seat main body 21, utilizing the elasticity of the leg rubber 25. Note that the body earth electrode 22 only needs to be appropriately positioned empirically or experimentally so as to come into contact with the right thigh of a person sitting on the toilet seat main body 21, and it is not essential that at least a portion of the body earth electrode 22 overlaps the leg rubber 25 in a plan view. Furthermore, the body earth electrode 22 only needs to be positioned so as to come into contact with a part of the body (for example, the buttocks) of a person sitting on the toilet seat main body 21, and it is not essential that it be positioned so as to come into contact with the right thigh.

[0045] The body earth electrode 22 is electrically connected to the electrocardiogram measurement module 30 by a third connection wiring 23. The third connection wiring 23 is, for example, a lead wire provided inside the toilet seat body 21. At least a portion of the third connection wiring 23 may be covered by an electromagnetic shield. The electromagnetic shield is made of a metal material electrically connected to the earth.

[0046] The seating sensor 24 detects that a person has sat on the toilet seat body 21 based on the weight (pressure) applied to the leg rubbers 25. When the seating sensor 24 detects that a person has sat on the toilet seat device 10, the toilet seat device 10 transitions from a standby state to preparations for operating normal toilet functions. The seating sensor 24 is provided, for example, inside the leg rubber 25 that overlaps with at least a portion of the body earth electrode 22, but may also be provided inside another leg rubber 25. The seating sensor 24 is realized, for example, by a piezoelectric sensor or a strain gauge sensor that can detect the weight applied to the leg rubbers 25. Although not shown, the detection result of the seating sensor 24 (electrical signal flag) is acquired by the MCU 34 of the electrocardiogram measurement module 30 via connecting wiring, not shown.

[0047] The multiple leg rubbers 25 are elastic members provided on the back surface of the toilet seat body 21 to cushion the movement between the toilet seat body 21 and the toilet bowl. When the toilet seat body 21 is viewed from above, the body earth electrode 22 overlaps one of the leg rubbers 25 (elastic members), improving contact between the right thigh and the body earth electrode 22 when a person sits on the toilet seat body 21. The leg rubber 25 is made of, for example, rubber, but may also be made of other materials such as elastomer. For example, four leg rubbers 25 are provided on the back surface of the toilet seat body 21, but the number of leg rubbers 25 is not particularly limited.

[0048] [Toilet seat device configuration: electrocardiogram measurement module] The electrocardiogram measurement module 30 acquires a first signal output by the first preamplifier PA1 via the first connection wiring 23L and acquires a second signal output by the second preamplifier PA2 via the second connection wiring 23R. The electrocardiogram measurement module 30 measures an electrocardiogram signal based on the acquired first and second signals. The electrocardiogram measurement module 30 includes a first high-pass filter 31, a second high-pass filter 32, an electrocardiogram signal measurement circuit 33, an MCU (Micro Controller Unit) 34, a communication circuit 35, a buffer amplifier 36, a body earth potential generation circuit 37, and an analog ground potential generation circuit 38. Although not shown, the electrocardiogram measurement module 30 operates by using a battery (e.g., a 3.7 V lithium polymer battery) as a power source to supply power to the power supply circuit.

[0049] The first high-pass filter 31 is a filter that reduces unnecessary low-frequency components (baseline fluctuations, etc.) of the acquired first signal. The first high-pass filter 31 is, for example, a first-order passive filter with a cutoff frequency of 0.1 Hz.

[0050] The second high-pass filter 32 is a filter that reduces unnecessary low-frequency components (baseline fluctuations, etc.) of the acquired second signal. The second high-pass filter 32 is, for example, a first-order passive filter with a cutoff frequency of 0.1 Hz.

[0051] It is desirable that the resistance values ​​of the first high-pass filter 31 and the second high-pass filter 32 have high accuracy, and for example, metal film chip resistors with a tolerance of ±0.1% are used as the resistance elements. Similarly, it is desirable that the capacitance values ​​of the first high-pass filter 31 and the second high-pass filter 32 have high accuracy, and for example, multilayer ceramic capacitors with a tolerance of ±10% are used as the capacitance elements.

[0052] The electrocardiogram signal measurement circuit 33 includes a differential amplifier 33a, a low-pass filter 33b, and an AD conversion circuit 33c. A first signal is input to the positive input terminal of the differential amplifier 33a, and a second signal is input to the negative input terminal of the differential amplifier 33a. The differential amplifier 33a amplifies the difference between the first and second signals by approximately 300 times, for example. The common-mode rejection ratio (CMRR) of the differential amplifier 33a is preferably 100 dB or more. Here, the common-mode rejection ratio, also referred to as the common-mode signal rejection ratio, represents the ability to reject a signal (common-mode signal) common to two inputs in a configuration having two inputs, such as a differential amplifier. The common-mode rejection ratio is given by the ratio of the gain (amplification factor) of the differential signal to the gain of the common-mode signal. The amplification factor of the differential amplifier 33a may be determined empirically or experimentally, and is not particularly limited.

[0053] The low-pass filter 33b reduces unnecessary high-frequency components of the signal output from the electrocardiogram signal measurement circuit 33 and outputs it as an electrocardiogram signal. The low-pass filter 33b is, for example, a third-order Sallen-Key active filter with a cutoff frequency of 75 Hz.

[0054] The AD conversion circuit 33c is a converter that samples the electrocardiogram signal (analog signal) output from the low-pass filter 33b and converts it into a digital signal. The AD conversion circuit 33c converts the electrocardiogram signal into a 12-bit digital signal by, for example, 1 kHz sampling.

[0055] The MCU 34 performs information processing for transmitting the electrocardiogram signal to the information terminal 40. For example, the MCU 34 performs downsampling processing on the electrocardiogram signal output from the AD conversion circuit 33c, thereby adjusting the number of samples of the electrocardiogram signal to match the communication standard (bit rate) of the wireless communication used by the communication circuit 35. Although not shown in detail, the MCU 34 includes a processor and a memory, and the functions of the MCU 34 are realized by the processor executing a program stored in the memory.

[0056] The communication circuit 35 is a communication module that enables the toilet seat device 10 to communicate with the information terminal 40. The communication circuit 35 is, for example, a communication module that transmits an electrocardiogram signal to the information terminal 40. The communication circuit 35 communicates with the information terminal 40 by wireless communication that complies with a communication standard such as BLE (Blutooth (registered trademark) Low Energy).

[0057] The second signal is input to the positive input terminal of the buffer amplifier 36, and the negative input terminal of the buffer amplifier 36 is electrically connected to the output terminal of the buffer amplifier 36. The gain of the buffer amplifier 36 is 1, and the buffer amplifier 36 performs impedance conversion without voltage amplification. In other words, the buffer amplifier 36 is provided to prevent the operation of the differential amplifier 33a from being affected by the operation of the body earth potential generating circuit 37. Note that the buffer amplifier 36 may perform voltage amplification.

[0058] The body earth potential generating circuit 37 generates a body earth potential by processing the second signal output from the buffer amplifier 36 to invert the polarity of the AC (Alternating Current) component of the second signal, and applies the generated body earth potential to the person sitting on the toilet seat main body 21 via the body earth electrode 22. The second signal contains environmental noise, and the body earth potential has the opposite polarity to the environmental noise. By applying such a body earth potential to the person sitting on the toilet seat main body 21, the environmental noise component is reduced from the electrocardiogram signal. In a configuration in which the body earth potential is applied to the person sitting on the toilet seat main body 21 via the body earth electrode 22, the influence of environmental noise is reduced on the human body side. Therefore, this configuration is effective in cases where the differential amplifier 33a cannot sufficiently cancel out in-phase environmental noise.

[0059] Note that environmental noise refers to noise that is not caused by a person (living body) sitting on the toilet seat body 21 and that depends on the measurement environment. For example, environmental noise is hum noise caused by AC power supplies, which in Japan is noise of 50 Hz or 60 Hz. Other examples of environmental noise include noise around 1 Hz caused by wind or airflow, noise of 300 Hz or higher caused by voice, and low-frequency noise in the range of 20 to 300 Hz emitted from construction sites or factories.

[0060] Specifically, the body earth potential generating circuit 37 includes an amplifier 37a, resistors R5 and R6, and a capacitor C1. The second signal is input to the negative input terminal of the amplifier 37a via the resistor R5. The positive input terminal of the amplifier 37a is electrically connected to the analog ground potential. The resistor R6 is a feedback resistor. The capacitor C1 is connected in parallel with the resistor R6, thereby providing the body earth potential generating circuit 37 with the function of a low-pass filter.

[0061] The cutoff frequency of the low-pass filter is, for example, 150 Hz, assuming that a third harmonic of 50 Hz hum noise (approximately five times the upper frequency limit of 30 Hz of the electrocardiogram signal) is to pass, but may be approximately 90 Hz, assuming that a signal approximately three times the upper frequency limit of 30 Hz of the electrocardiogram signal is to pass. The order and cutoff frequency of the low-pass filter may be determined theoretically, empirically, or experimentally as appropriate.

[0062] In a configuration that simply inverts and amplifies a signal near the intermediate potential, such as the inverting amplifier circuit of the electrocardiogram measuring device described in Patent Document 1, even if the phase is rotated by 180° or more in an attempt to cancel out high-frequency noise, the loop gain does not become smaller than 1, and the inverting amplifier circuit may unintentionally oscillate. In contrast, in the body earth potential generating circuit 37, the frequency band is limited by a low-pass filter, which prevents the body earth potential generating circuit 37 from unintentionally oscillating.

[0063] The resistor R5 has a resistance of, for example, 5 kΩ, the resistor R6 has a resistance of, for example, 1 MΩ, and the capacitor C1 has a resistance of, for example, 940 pF. The output terminal of the amplifier 37a is electrically connected to the body earth electrode 22 by a third connection wire .

[0064] The analog ground potential generating circuit 38 includes an amplifier 38a, resistors R7 and R8, and generates a power supply voltage of 0.9V from a power supply voltage of 1.8V through voltage division by resistors R7 and R8. The amplifier 38a functions as a buffer amplifier, and the 0.9V power supply voltage is used as the analog ground potential. The amplifier 38a consumes a current of, for example, 1 mA, and can maintain the analog ground potential at the power supply voltage of 0.9V.

[0065] [Information terminal configuration] The information terminal 40 receives the electrocardiogram signal transmitted by the communication circuit 35 of the electrocardiogram measurement module 30 and displays the received electrocardiogram signal and the analysis result of the electrocardiogram signal. The information terminal 40 is, for example, a portable information terminal such as a smartphone or a tablet terminal, but may also be a stationary information terminal such as a personal computer. The information terminal 40 is realized by installing a dedicated application program for the measurement system 100 in a general-purpose device, but may also be a device dedicated to the measurement system 100. FIG. 4 is a block diagram showing the functional configuration of the information terminal 40. As shown in FIG. 4, the information terminal 40 includes a communication unit 41, an information processing unit 42, a storage unit 43, and a display unit 44.

[0066] The communication unit 41 is a communication module (communication circuit) that enables the information terminal 40 to receive electrocardiogram signals transmitted by the communication circuit 35 of the electrocardiogram measurement module 30. The communication performed by the communication unit 41 is, for example, wireless communication.

[0067] The information processing unit 42 performs information processing related to displaying electrocardiogram signals, analyzing electrocardiogram signals, and displaying the analysis results of the electrocardiogram signals. The information processing unit 42 is realized by, for example, a microcomputer, but may also be realized by a processor. The functions of the information processing unit 42 are realized, for example, by the microcomputer or processor constituting the information processing unit 42 executing a computer program stored in the storage unit 43.

[0068] The storage unit 43 is a storage device that stores information necessary for the above information processing, computer programs executed by the information processing unit 42, etc. The storage unit 43 is realized by, for example, a semiconductor memory.

[0069] The display unit 44 displays the electrocardiogram signal and the analysis results of the electrocardiogram signal. The display unit 44 is realized by a display panel such as a liquid crystal panel or an organic EL (Electro Luminescence) panel, for example.

[0070] [Measurement system operation example 1] Next, a description will be given of a first operational example of the measurement system 100. FIG.

[0071] When a person sits on the toilet seat 20 (toilet seat body 21), the seating sensor 24 detects that the person is sitting on the toilet seat body 21 based on the weight applied to the leg rubber 25 (S11). The left thigh of the seated person unconsciously positions itself directly above the first electrode 26L, the right thigh of the seated person unconsciously positions itself directly above the second electrode 26R, and the right thigh of the seated person unconsciously comes into direct contact with the body earth electrode 22. Upon detecting that the person has sat on the toilet seat body 21, the MCU 34 applies a body earth potential (provisional value) to the person via the body earth electrode 22 and activates the first active electrode 22L, the second active electrode 22R, and the electrocardiogram measurement module 30. During this process, the body earth potential generating circuit 37 changes the body earth potential by performing a process on the second signal from the second preamplifier PA2 to invert the polarity of the AC component of the second signal, and applies the generated body earth potential to the person via the body earth electrode 22 to reduce hum noise (S12).

[0072] The electrocardiogram signal measurement circuit 33 measures an electrocardiogram signal based on the first signal from the first preamplifier PA1 and the second signal from the second preamplifier PA2, and the digitally coded electrocardiogram signal is sent to the MCU 34 (S13). FIG. 6 is a diagram showing an example of the waveform of an electrocardiogram signal acquired at the thigh. In FIG. 6, the waveform of the electrocardiogram signal is displayed for 10 seconds. In step S13, a body earth potential having a polarity opposite to that of the AC component of the second signal containing environmental noise is applied to the human body, thereby reducing the influence of environmental noise on the electrocardiogram signal measured in step S13. The communication circuit 35 transmits the acquired electrocardiogram signal to the information terminal 40 (S14).

[0073] The communication unit 41 of the information terminal 40 receives the electrocardiogram signal from the communication circuit 35. The information processing unit 42 analyzes the received electrocardiogram signal (S15). The information processing unit 42 applies an additional digital filter (e.g., a high-pass filter with a cutoff frequency of 2 Hz) to smooth the person's baseline fluctuation, detects R waves in the electrocardiogram signal using a predetermined peak detection algorithm (e.g., a Hamilton algorithm), and calculates R-R intervals based on the detected R waves. In other words, the information processing unit 42 calculates the heart rate. The information processing unit 42 also displays the electrocardiogram signal itself and the calculated R-R intervals (an example of the analysis results) on the display unit 44 (S16). FIG. 7 is a diagram showing an example of display of the electrocardiogram signal and the R-R intervals (instantaneous heart rate) on the display unit 44 of the information terminal 40. Note that in step S16, it is sufficient that at least one of the electrocardiogram signal itself and the analysis results is displayed.

[0074] When the peak detection algorithm is applied, if the reduction of hum noise (50 Hz, 60 Hz) is insufficient, the information processing unit 42 may apply an additional digital filter (for example, a notch filter with a center frequency of 60 Hz and a bandwidth of 4 Hz).

[0075] In this way, the measurement system 100 can measure the electrocardiogram signal of a person sitting on the toilet seat device 10, and display the measured electrocardiogram signal and the analysis results of the electrocardiogram signal on the information terminal 40.

[0076] [Variation 1 of the circuit configuration of the toilet seat device] Next, a description will be given of the circuit configuration of the toilet seat device according to Modification 1. Fig. 8 is a diagram showing the circuit configuration of the toilet seat device according to Modification 1.

[0077] 1, IC chip sets are used as the first preamplifier PA1, the second preamplifier PA2, and the differential amplifier 33a, and therefore the first preamplifier PA1, the second preamplifier PA2, and the differential amplifier 33a all operate by receiving a voltage of 1.8 V. The IC chip set here is, for example, a chip set consisting of two or more types of ASICs (Application Specific Integrated Circuits) for measuring electrocardiogram signals.

[0078] In contrast, in the toilet seat apparatus 10a according to Modification 1 shown in FIG. 8, the first preamplifier PA1a provided in the first active electrode 22La and the second preamplifier PA2a provided in the second active electrode 22Ra each receive a voltage of 3.3V for operation, unlike the differential amplifier 33a. This allows the toilet seat apparatus 10a to use highly versatile operational amplifiers as the first preamplifier PA1a and the second preamplifier PA2a. Furthermore, it becomes possible to input signals with larger amplitudes to the first preamplifier PA1a and the second preamplifier PA2a. The first preamplifier PA1a is another example of a first amplifier, and the second preamplifier PA2a is another example of a second amplifier.

[0079] The first preamplifier PA1a and the second preamplifier PA2a may be, for example, an operational amplifier having an input impedance of 1 GΩ or more at a frequency of 10 Hz and an input noise of 2 μVp-p or less in the frequency band of 0.1 Hz to 30 Hz.

[0080] [Variation 2 of the circuit configuration of the toilet seat device] Next, a description will be given of the circuit configuration of the toilet seat device according to Modification 2. Fig. 9 is a diagram showing the circuit configuration of the toilet seat device according to Modification 2.

[0081] The toilet seat device 10b according to Modification 2 shown in FIG. 9 has a configuration in which the first active electrode 22L in the toilet seat device 10 is replaced with a first active electrode 22Lb, and the second active electrode 22R is replaced with a second active electrode 22Rb.

[0082] The first active electrode 22Lb has a configuration in which a third resistor element R3 and a first switch element S1 are added to the first active electrode 22L.

[0083] The third resistor R3 has a resistance value lower than that of the first resistor R1. The resistance value of the third resistor R3 is, for example, 10 MΩ, which is 1 / 1000 or less of the resistance value (for example, 10 GΩ) of the first resistor R1. The third resistor R3 is, for example, a chip-type resistor element, but may also be a resistor element with leads. One end of the third resistor R3 is electrically connected to the other end of the first switch element S1, and the other end of the third resistor R3 is electrically connected to the analog ground potential.

[0084] One end of the first switch element S1 is electrically connected to the first wiring 27L, and the other end of the first switch element S1 is electrically connected to one end of the third resistor element R3. The first switch element S1 turns on and off the electrical connection between the first wiring 27L and the third resistor element R3 based on a control signal output from the MCU 34. The first switch element S1 is, for example, a semiconductor switching element such as a CMOS MOSFET.

[0085] The second active electrode 22Rb has a configuration in which a fourth resistor element R4 and a second switch element S2 are added to the second active electrode 22R.

[0086] The fourth resistor R4 has a resistance value lower than that of the second resistor R2. The resistance value of the fourth resistor R4 is, for example, 10 MΩ, which is 1 / 1000 or less of the resistance value (for example, 10 GΩ) of the second resistor R2. The fourth resistor R4 is, for example, a chip-type resistor element, but may also be a resistor element with leads. One end of the fourth resistor R4 is electrically connected to the other end of the second switch element S2, and the other end of the fourth resistor R4 is electrically connected to the analog ground potential.

[0087] One end of the second switch element S2 is electrically connected to the second wiring 27R, and the other end of the second switch element S2 is electrically connected to one end of the fourth resistor element R4. The second switch element S2 turns on and off the electrical connection between the second wiring 27R and the fourth resistor element R4 based on a control signal output from the MCU 34. The second switch element S2 is, for example, a semiconductor switching element such as a CMOS MOSFET.

[0088] In this way, in the toilet seat apparatus 10b, the first wiring 27L is electrically connected to the analog ground potential via the third resistor R3, which has a resistance value lower than the first resistor R1, and the first switch element S1, which is connected in series with the third resistor R3. Also, in the toilet seat apparatus 10b, the second wiring 27R is electrically connected to the analog ground potential via the fourth resistor R4, which has a resistance value lower than the second resistor R2, and the second switch element S2, which is connected in series with the fourth resistor R4.

[0089] In Patent Document 2, the first resistor corresponding to the first resistor R1 (second resistor R2) of the present application and the second resistor corresponding to the third resistor R3 (fourth resistor R4) of the present application are electrically connected to earth potential, not analog ground potential (intermediate potential). If the first resistor R1 (second resistor R2) and the third resistor R3 (fourth resistor R4) are electrically connected to analog ground potential (intermediate potential), as in the toilet seat device 10b, voltage noise is absorbed by the buffer operation of the amplifier 38a, and the earth potential (0 V) is less likely to shift during noise removal. Therefore, the first preamplifier PA1 (second preamplifier PA2) continues to operate even when voltage noise is reduced. Therefore, the toilet seat device 10b can more appropriately reduce voltage noise than the electrocardiogram sensor described in Patent Document 2.

[0090] [Example 2] In the toilet seat apparatus 10, friction between the thighs and the toilet seat body 21 causes minute voltage noise to accumulate in the first electrode 26L and the second electrode 26R. Since the first wiring 27L and the second wiring 27R have high impedance and no path exists for the voltage noise to escape, the voltage noise may be mixed into the electrocardiogram signal. FIG. 10 shows an example of the waveform of an electrocardiogram signal mixed with such voltage noise. The toilet seat apparatus 10b has been designed to deal with such voltage noise. Specifically, the toilet seat apparatus 10b can release the voltage noise to the analog ground by turning on the first switch element S1 and the second switch element S2.

[0091] Hereinafter, a second operational example of the measurement system 100 will be described, in which the measurement system 100 includes a toilet seat device 10b instead of the toilet seat device 10. FIG.

[0092] The processing in steps S21 to S24 is similar to the processing in steps S11 to S14, and therefore a detailed description thereof will be omitted.

[0093] In step S24, the communication unit 41 of the information terminal 40 receives the electrocardiogram signal from the communication circuit 35. The information processing unit 42 analyzes the received electrocardiogram signal (S25). Assume that the electrocardiogram signal received in step S24 contains voltage noise and has a waveform as shown in FIG. 10. Such an electrocardiogram signal has a larger amplitude than a normal electrocardiogram signal (FIG. 6). Therefore, in step S25, the information processing unit 42 determines whether the amplitude of the electrocardiogram signal is equal to or greater than a threshold, and if the amplitude of the electrocardiogram signal is equal to or greater than the threshold, determines that the electrocardiogram signal cannot be measured (measurement abnormality). The threshold is, for example, 200 μV, but may be determined empirically or experimentally as appropriate.

[0094] If the information processing unit 42 determines that the electrocardiogram signal has not been measured, it transmits a request to the toilet seat device 10b to measure the electrocardiogram signal again (S26). More specifically, the request to measure the electrocardiogram again is transmitted to the toilet seat device 10b by the communication unit 41.

[0095] The communication circuit 35 of the toilet seat device 10b receives the re-measurement request. The MCU 34 performs a discharge process based on the received re-measurement request (S27). Specifically, the MCU 34 turns on each of the first switch element S1 and the second switch element S2, which are in the off state, for a predetermined period of time, and then returns them to the off state. In this way, the MCU 34 attempts to discharge voltage noise to the analog ground. The predetermined period is, for example, 5 seconds, but may be determined empirically or experimentally as appropriate.

[0096] After the discharge process, the electrocardiogram signal measurement circuit 33 measures the electrocardiogram signal based on the first signal from the first preamplifier PA1 and the second signal from the second preamplifier PA2 (S28). The communication circuit 35 transmits the acquired electrocardiogram signal to the information terminal 40 (S29).

[0097] The communication unit 41 of the information terminal 40 receives the electrocardiogram signal from the communication circuit 35. The information processing unit 42 analyzes the received electrocardiogram signal (S30). In step S30, since the voltage noise has been reduced in step S27, it is determined that the electrocardiogram signal is normal. Then, the information processing unit 42 further detects R waves in the electrocardiogram signal using a predetermined peak detection algorithm and calculates the RR interval based on the detected R waves. In other words, the information processing unit 42 calculates the heart rate.

[0098] Thereafter, the information processing unit 42 displays the electrocardiogram signal itself and the calculated RR intervals on the display unit 44 (S31). As a result, as shown in Fig. 7, the electrocardiogram signal and the RR intervals (heart rate) for two seconds are displayed on the display unit 44 of the information terminal 40. Note that in step S31, it is sufficient that at least one of the electrocardiogram signal itself and the analysis results (such as the heart rate and the transition of the RR intervals over time) is displayed.

[0099] In this way, when it is determined that the electrocardiogram signal cannot be measured, the measurement system 100 equipped with the toilet seat device 10b can perform a discharge process to reduce voltage noise and then measure the electrocardiogram signal again.

[0100] [Effects, etc.] As explained above, the toilet seat device 10 includes a first electrode 26L arranged on the rear surface of or inside the toilet seat body 21, the first electrode 26L being capacitively coupled to the left thigh of a person sitting on the toilet seat body 21, a first preamplifier PA1 electrically connected to the first electrode 26L, a second electrode 26R arranged on the rear surface of or inside the toilet seat body 21, the second electrode 26R being capacitively coupled to the right thigh of a person sitting on the toilet seat body 21, a second preamplifier PA2 electrically connected to the second electrode 26R, and a signal output from the first preamplifier PA1. The toilet seat includes an electrocardiogram signal measurement circuit 33 that measures an electrocardiogram signal based on a first signal input from the toilet seat body 21 and a second signal output from the second preamplifier PA2, a body earth electrode 22 that is at least partially exposed to the outside from the front side of the toilet seat body 21 and that comes into contact with a person sitting on the toilet seat body 21, and a body earth potential generation circuit 37 that generates a body earth potential by processing the second signal to invert the polarity of the AC component of the second signal and applies the generated body earth potential to the person via the body earth electrode 22. The first preamplifier PA1 is an example of a first amplifier, and the second preamplifier PA2 is an example of a second amplifier.

[0101] Such a toilet seat device 10 can reduce the influence of environmental noise on the electrocardiogram signal on the human body side by applying the body earth potential to the person sitting on the toilet seat main body 21. In other words, the toilet seat device 10 can improve the measurement quality of the electrocardiogram signal.

[0102] Furthermore, for example, the toilet seat body 21 is made of a resin material, and the thickness of the portion of the toilet seat body 21 located between the first electrode 26L and the left thigh and the thickness of the portion of the toilet seat body 21 located between the second electrode 26R and the right thigh are each 2 mm or less. The area of ​​the first electrode 26L and the area of ​​the second electrode 26R are each 10,000 mm 2 The first electrode 26L is capacitively coupled to the left thigh with a capacitance of 100 pF or more, and the second electrode 26R is capacitively coupled to the right thigh with a capacitance of 100 pF or more.

[0103] Such a toilet seat device 10 can improve the measurement quality of the electrocardiogram signal by appropriately capacitively coupling the first electrode 26L and the left thigh and appropriately capacitively coupling the second electrode 26R and the right thigh.

[0104] Furthermore, for example, each of the first preamplifier PA1 and the second preamplifier PA2 has an input impedance of 1 GΩ or more at a frequency of 10 Hz, and an input noise of 2 μVp-p or less in the frequency band of 0.1 Hz to 30 Hz.

[0105] In such a toilet seat device 10, by employing amplifiers having performance suitable for measuring electrocardiogram signals as the first preamplifier PA1 and the second preamplifier PA2, it is possible to improve the measurement quality of electrocardiogram signals.

[0106] Furthermore, for example, the toilet seat device 10 further includes a first wiring 27L that electrically connects the first electrode 26L and the first preamplifier PA1, the first wiring 27L having at least a portion covered by an electromagnetic shield, and a second wiring 27R that electrically connects the second electrode 26R and the second preamplifier PA2, the second wiring 27R having at least a portion covered by an electromagnetic shield.

[0107] Such a toilet seat device 10 can improve the measurement quality of the electrocardiogram signal by covering with an electromagnetic shield the first wiring 27L that electrically connects the first electrode 26L and the first preamplifier PA1, and the second wiring 27R that electrically connects the second electrode 26R and the second preamplifier PA2.

[0108] For example, the first wiring 27L is electrically connected to the analog ground potential via a first resistor R1 having a resistance value of 10 GΩ or more, and the second wiring 27R is electrically connected to the analog ground potential via a second resistor R2 having a resistance value of 10 GΩ or more.

[0109] In such a toilet seat device 10, the first wiring 27L and the second wiring 27R are each electrically connected to the analog ground potential via a resistive element having a relatively high resistance value, thereby improving the measurement quality of the electrocardiogram signal.

[0110] In addition, for example, in the toilet seat apparatus 10b, the first wiring 27L is electrically connected to the analog ground potential via a third resistor R3 having a resistance value lower than the first resistor R1 and a first switch element S1 connected in series with the third resistor R3. The second wiring 27R is electrically connected to the analog ground potential via a fourth resistor R4 having a resistance value lower than the second resistor R2 and a second switch element S2 connected in series with the fourth resistor R4.

[0111] When minute voltage noise accumulates in the first electrode 26L and the second electrode 26R, the toilet seat device 10b can release the voltage noise to the analog ground by turning on the first switch element S1 and the second switch element S2. By releasing the voltage noise to the analog ground, the toilet seat device 10b can improve the measurement quality of the electrocardiogram signal.

[0112] Furthermore, for example, leg rubbers 25 are provided on the rear surface of the toilet seat body 21. In a plan view, at least a portion of the body earth electrode 22 overlaps with the leg rubbers 25. The leg rubbers 25 are an example of an elastic member.

[0113] In such a toilet seat device 10, the elasticity of the leg rubber 25 can be used to press the body earth electrode 22 against the body of a person sitting on the toilet seat body 21.

[0114] Furthermore, for example, leg rubbers 25 are provided on the rear surface of the toilet seat body 21. The toilet seat device 10 further includes a seating sensor 24 that detects when a person sits on the toilet seat body based on the weight applied to the leg rubbers 25. The body earth potential generating circuit 37 generates a body earth potential when the seating sensor 24 detects that a person has sat on the toilet seat body 21.

[0115] Such a toilet seat device 10 can generate a body earth potential when a person sits on the toilet seat body 21.

[0116] In addition, the signal processing method executed by the information terminal 40 connected to the toilet seat device includes an acquisition step S14 of acquiring an electrocardiogram signal measured by the toilet seat device 10, an analysis step S15 of analyzing the acquired electrocardiogram signal, and a display step S16 of displaying the results of the analysis.

[0117] Such a signal processing method can display the analysis results of the electrocardiogram signal.

[0118] Also, for example, in the analysis step S15, R waves of the acquired electrocardiogram signal are detected and RR intervals are calculated based on the detected R waves. In the display step S16, the heart rate or RR intervals are displayed.

[0119] Such a signal processing method can display the RR interval.

[0120] (Other embodiments) Although the embodiments have been described above, the present invention is not limited to such embodiments.

[0121] For example, the circuit configurations described in the above embodiments are merely examples, and the present invention is not limited to the above circuit configurations. In other words, circuits that can achieve the characteristic functions of the present invention, similar to the above circuit configurations, are also included in the present invention. For example, the present invention also includes a circuit in which an element such as a switching element (transistor), a resistive element, or a capacitive element is connected in series or parallel to a certain element, as long as the circuit configuration can achieve the same functions as the above circuit configurations.

[0122] In the above-described embodiment, the processing performed by a specific processing unit may be performed by another processing unit. The order of multiple processing operations may be changed, or multiple processing operations may be performed in parallel.

[0123] Furthermore, the general or specific aspects of the present invention may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0124] For example, the present invention may be realized as the measurement system according to the above-described embodiment, or as a measurement method for an electrocardiogram signal executed by the measurement system. Furthermore, the present invention may be realized as a program for causing a computer to execute such a measurement method, or as a computer-readable non-transitory recording medium on which such a program is recorded.

[0125] The present invention may also be realized as a signal processing method executed by a toilet seat device or an information terminal, or as a program for causing a computer to execute such a signal processing method. The present invention may also be realized as a computer-readable non-transitory recording medium on which such a program is recorded.

[0126] Furthermore, the measurement system may be realized as a single device or may be realized by multiple devices. When the measurement system is realized by multiple devices, the components of the measurement system described in the above embodiment may be distributed among the multiple devices in any manner.

[0127] In addition, as long as it does not deviate from the spirit of the present invention, various modifications that a person skilled in the art may make to this embodiment, or forms constructed by combining components from different embodiments, may also be included within the scope of one or more aspects. [Explanation of symbols]

[0128] 10, 10a, 10b Toilet seat device 21 Toilet seat body 22 Body earth electrode 24 Seat sensor 25 Leg rubber (elastic material) 26L 1st electrode 26R 2nd electrode 27L 1st wiring 27R 2nd wiring 33 Electrocardiogram signal measurement circuit 37 Body earth potential generation circuit PA1, PA1a 1st preamplifier (1st amplifier) PA2, PA2a Second preamplifier (second amplifier) R1 First resistor element R2 Second resistor element R3 Third resistor element R4 Fourth resistor element S1 First switch element S2 Second switch element

Claims

1. A toilet seat device, a first electrode disposed on the rear surface or inside of the toilet seat body, the first electrode being capacitively coupled with the left thigh of a person sitting on the toilet seat body; a first amplifier electrically connected to the first electrode; a second electrode disposed on the rear surface or inside of the toilet seat body, the second electrode being capacitively coupled with the right thigh of the person sitting on the toilet seat body; a second amplifier electrically connected to the second electrode; an electrocardiogram signal measurement circuit that measures an electrocardiogram signal based on a first signal output from the first amplifier and a second signal output from the second amplifier; a body earth electrode, at least a portion of which is exposed to the outside from the front side of the toilet seat body and comes into contact with the person sitting on the toilet seat body; a body earth potential generating circuit that generates a body earth potential by performing a process on the second signal to invert the polarity of an AC (Alternating Current) component of the second signal, and applies the generated body earth potential to the person via the body earth electrode; An elastic member is provided on the back surface of the toilet seat body, The toilet seat device further includes a seating sensor that detects when the person sits on the toilet seat body based on the weight applied to the elastic member, The body earth potential generating circuit generates the body earth potential when the seat sensor detects that the person has sat on the toilet seat body. Toilet seat device.

2. The toilet seat body is made of a resin material, the thickness of the portion of the toilet seat body located between the first electrode and the left thigh, and the thickness of the portion of the toilet seat body located between the second electrode and the right thigh are each 2 mm or less; The area of ​​the first electrode and the area of ​​the second electrode are each 10,000 mm ２ That's all, the first electrode is capacitively coupled to the left thigh with a capacitance of 100 pF or more; The second electrode is capacitively coupled to the right thigh with a capacitance of 100 pF or more.

2. The toilet seat apparatus of claim 1.

3. Each of the first amplifier and the second amplifier has an input impedance of 1 GΩ or more at a frequency of 10 Hz, and an input noise of 2 μVp-p or less in a frequency band of 0.1 Hz to 30 Hz.

3. A toilet seat device according to claim 1 or 2.

4. moreover, a first wiring electrically connecting the first electrode and the first amplifier, the first wiring being at least partially covered by an electromagnetic shield; a second wiring that electrically connects the second electrode and the second amplifier, the second wiring being at least partially covered by an electromagnetic shield; The toilet seat device according to any one of claims 1 to 3.

5. the first wiring is electrically connected to an analog ground potential via a first resistor element having a resistance value of 10 GΩ or more; The second wiring is electrically connected to the analog ground potential via a second resistor element having a resistance value of 10 GΩ or more.

5. The toilet seat apparatus of claim 4.

6. the first wiring is electrically connected to the analog ground potential via a third resistor element having a resistance value lower than that of the first resistor element and a first switch element connected in series with the third resistor element; The second wiring is electrically connected to the analog ground potential via a fourth resistor element having a resistance value lower than that of the second resistor element and a second switch element connected in series with the fourth resistor element.

6. The toilet seat apparatus of claim 5.

7. In a plan view, at least a portion of the body earth electrode overlaps with the elastic member. The toilet seat device according to any one of claims 1 to 6.

8. A signal processing method executed by an information terminal connected to the toilet seat device according to any one of claims 1 to 7, an acquiring step of acquiring the electrocardiogram signal measured by the toilet seat device; an analyzing step of analyzing the acquired electrocardiogram signal; and displaying the results of the analysis. Signal processing methods.

9. In the analyzing step, an R wave of the acquired electrocardiogram signal is detected, and an R-R interval is calculated based on the detected R wave. In the display step, the heart rate or the RR interval is displayed.

9. The signal processing method according to claim 8.

10. A program for causing a computer to execute the signal processing method according to claim 8 or 9.

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