Seat wet detection device

Abstract

To provide a seat wet detection device capable of simply and accurately detecting wet on a seat part of a seat in a wider range.SOLUTION: A seat wet detection device includes: a sensor 11 that is provided at a height downwardly facing a seat part 3 of a seat 1 and transmits an electromagnetic wave toward a seat surface of the seat part 3 opposing to a front side and receives a reflection wave of the electromagnetic wave on the front side; and a reflection part 31 that is provided so as to overlap with the seat surface in the seat part 3 in plan view and serves as a seat part frame 30 in the seat part 3. Wet of the seat part 3 can be determined on the basis of a degree of attenuation of signal intensity due to a water content of the reflection wave from the reflection part 31.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a seat wetness detection device for detecting wetness of a seat portion. [Background technology]

[0002] The applicant has already proposed a wet seat detection device in Patent Document 1 that can be miniaturized, easily attached to a seat, and can accurately detect wetness of a seat with simple control. This wet seat detection device was equipped with a millimeter wave sensor that transmits and receives millimeter waves to the seat, and a reflector that is placed inside the seat and reflects the millimeter waves from the millimeter wave sensor, and was able to determine whether the seat was wet based on the degree of attenuation of the signal strength of the waves reflected from the reflector due to moisture.

[0003] In a specific embodiment of such a seat wetness detection device, the millimeter-wave sensor is provided in a sleeve portion on the side of the seat portion of the seat, and is positioned so as to irradiate millimeter waves from the side toward the seat surface of the seat portion located immediately below the millimeter-wave sensor. Also, multiple small, approximately rectangular metal plates are arranged at different positions as reflectors under the seat surface of the seat portion, which is within the irradiation range of the millimeter waves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7239647 Summary of the Invention [Problem to be solved by the invention]

[0005] With regard to the specific embodiment of the seat wetness detection device described above, an improvement was desired to solve the following new problem: The millimeter-wave sensor is mounted on the sleeve of the seat, on the side of the seat surface, and emits millimeter waves from a position close to the side of the seat surface. As a result, the millimeter-wave irradiation range on the seat surface is relatively narrow, and even if the metal plate, which serves as the reflector, is shifted even slightly from the front of the millimeter-wave sensor, the reflection intensity decreases drastically, further narrowing the detection area.

[0006] Furthermore, due to the relative positions of the millimeter-wave sensor in the sleeve and the seat, blind spots in the millimeter-wave irradiation range, particularly on both sides of the front edge of the seat, were prone to occur, making it difficult to detect wetness in those areas. Furthermore, because multiple metal plates serving as reflective parts were placed separately from the seat frame, the number of parts and assembly steps increased, resulting in higher costs. Furthermore, even a slight deviation in the angle of each metal plate from the angle directly facing the millimeter-wave sensor significantly weakened the reflected millimeter waves, as mentioned above, making it necessary to adjust the reflective angle of the metal plates, which was troublesome.

[0007] The present invention was made in response to the problems associated with the prior art described above, and aims to provide a seat wetness detection device that can ensure a wide irradiation range of electromagnetic waves, including millimeter waves, covering the entire seat surface of the seat, thereby eliminating blind spots on the seat surface where water leaks cannot be detected, and eliminating the need for the tedious task of adjusting the reflection angle of the reflector, thereby enabling easy and accurate detection of seat wetness over a wider area without incurring higher costs. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one aspect of the present invention is to provide a method for manufacturing a semiconductor device comprising: A seat wetness detection device for detecting wetness of a seat, a sensor that is provided at a height facing downward at the seat portion of the seat, that transmits electromagnetic waves from the front side toward the seat surface of the opposing seat portion, and that receives, from the front side, waves that are reflected back from the electromagnetic waves; A reflective portion is provided in the seat portion so as to overlap the seat surface in a plan view and serves as a seat frame in the seat portion, the reflecting portion is capable of receiving electromagnetic waves transmitted from the sensor over the entire area of ​​its upper surface side and reflecting the waves toward the sensor, The wetness of the seat can be determined based on the degree of attenuation of the signal strength of the reflected wave received by the sensor due to moisture. [Effects of the Invention]

[0009] According to the seat wetness detection device of the present invention, wetness of the seat portion of the seat can be detected easily and accurately over a wider range without increasing costs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a seat to which a seat wetness detection device according to an embodiment of the present invention is applied; [Figure 2] 1 is a perspective view showing the internal structure of a seat to which a seat wetness detection device according to an embodiment of the present invention is applied; [Figure 3] 1 is a front view showing the internal structure of a seat to which a seat wetness detection device according to an embodiment of the present invention is applied. [Figure 4] 1 is a plan view showing the internal structure of a seat to which a seat wetness detection device according to an embodiment of the present invention is applied. [Figure 5] 1 is a side view showing the internal structure of a seat to which a seat wetness detection device according to an embodiment of the present invention is applied. [Figure 6] 1 is a perspective view showing a seat frame that also serves as a reflector of the seat wetness detection device according to the present embodiment. FIG. [Figure 7] 1 is a plan view showing a seat frame that also serves as a reflector of the seat wetness detection device according to the present embodiment. FIG. [Figure 8] 1 is a side view showing a seat frame that also serves as a reflector of the seat wetness detection device according to the present embodiment. FIG. [Figure 9] 1 is a bottom view showing a seat frame that also serves as a reflector of the seat wetness detection device according to the present embodiment. FIG. [Figure 10]3 is a perspective view showing a corner reflector forming a reflecting portion of the seat wetness detection device according to the present embodiment. FIG. [Figure 11] 1 is a perspective view showing a corner reflector unit that forms a reflecting portion of a seat wetness detection device according to an embodiment of the present invention; [Figure 12] 3 is a plan view showing a corner reflector unit that forms a reflecting portion of the seat wetness detection device according to the present embodiment. FIG. [Figure 13] 3 is a side view showing a support bracket for a reflector of the seat wetness detection device according to the embodiment; FIG. [Figure 14] 3 is a plan view showing a support bracket for a reflector of the seat wetness detection device according to the embodiment; FIG. [Figure 15] 3 is a front view showing a support bracket for a reflector of the seat wetness detection device according to the embodiment; FIG. [Figure 16] 1 is a block diagram illustrating a seat wetness detection device according to an embodiment of the present invention; [Figure 17] 1 is an explanatory diagram showing how millimeter waves from a millimeter wave sensor of a wet seat detection device according to this embodiment change depending on whether the seat is in a dry state or a wet state. [Figure 18] 1 is an explanatory diagram showing an example of a method for detecting seat wetness in the seat wetness detection device according to the present embodiment; [Figure 19] 10 is a flowchart showing an example of processing performed after detecting seat wetness in the seat wetness detection device according to the present embodiment. [Figure 20] FIG. 10 is a perspective view showing the internal structure of a seat to which a wet seat detection device according to a first modified example of the present embodiment is applied. [Figure 21] 10 is a plan view showing the internal structure of a seat to which a wet seat detection device according to Modification 1 of the present embodiment is applied. FIG. [Figure 22] 10 is an explanatory diagram showing an example of a graph showing the signal intensity of a reflected wave in a seat wetness detection device according to Modification 1 of the present embodiment. FIG. [Figure 23] FIG. 10 is a perspective view showing the internal structure of a seat to which a wet seat detection device according to a second modified example of the present embodiment is applied. [Figure 24]10 is a plan view showing the internal structure of a seat to which a wet seat detection device according to a second modified example of the present embodiment is applied. FIG. [Figure 25] 10 is an explanatory diagram showing an example of a graph displaying the signal intensity of a wave reflected by a seat wetness detection device according to a second modified example of the present embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a representative embodiment of the present invention will be described with reference to the drawings. 1 to 19 show one embodiment of the present invention. The seat wetness detection device 10 according to this embodiment uses electromagnetic waves, particularly millimeter-wave radar, to detect wetness of a seat 1, particularly the seat portion 3. The seat 1 will be described below as an example of a seat installed in a passenger compartment of a railway vehicle. Note that the components, shapes, values, etc. shown in the embodiment described below are all examples of the present invention and are not intended to limit the present invention.

[0012] <Seat 1 Overview> As shown in Figure 1, seat 1 comprises a seat section 3 attached to a base 2, with a backrest 4 supported on the rear end of seat section 3. Base 2 is a metal base that supports the entire seat 1 on the floor, and includes, for example, a pair of side plates 20, 20 fixed opposite each other on the left and right. The front ends of each side plate 20 are connected via a front shaft 21, the rear ends of each side plate 20 are connected via a rear shaft 22, and the approximate centers of each side plate 20 are connected via an intermediate shaft 23.

[0013] As shown in Figures 1 to 5, the seat 3 is composed of a cushion 3a attached to a seat frame 30, which is a seat frame fixed to the base 2, and a cover covering the surface of the cushion 3a, including the seat surface. The seat frame 30 is made of metal and is formed into a roughly rectangular panel overall, but as shown in Figures 6 to 9, it is configured to also serve as a reflector 31, which will be described later. A mounting portion 30b protrudes from the rear end of the seat frame 30, supporting a backrest frame 40, which will be described below. The seat frame 30 is attached to the upper sides of the front shaft 21 and the rear shaft 22 via mounting brackets 30c. Although not shown, armrests may be provided on both sides of the seat 3, as in Patent Document 1.

[0014] The backrest 4 is made by attaching a cushion 4a to a backrest frame 40, which is a back frame supported at the rear end of the seat frame 30, and covering the surface of the cushion 4a with a cover. The backrest frame 40 is formed into a vertically long, approximately rectangular panel by combining multiple metal materials. Here, the backrest frame 40 is rotatably supported at the rear end of the seat frame 30, and the tilt angle of the backrest 4 is preferably configured to be adjustable via a damper 5 of the reclining mechanism.

[0015] As shown in Fig. 1, the upper side of the backrest 4 is provided with front side portions 4b that protrude forward from both the left and right sides, and a separate headrest 4c is attached between them. One of the front side portions 4b is provided with a reading light 6, and a millimeter-wave sensor 11, which will be described later, is provided inside and beside the reading light 6. As shown in Fig. 2 in more detail, a support bracket 50 for attaching the millimeter-wave sensor 11 is fixed to one side end of the upper end portion 41 of the backrest frame 40. The support bracket 50 will be described in detail below, along with the millimeter-wave sensor 11.

[0016] In such a seat 1, the seat frame 30 (reflecting portion 31) in the seat 3, which is the target of wetness detection, is made of metal and does not transmit electromagnetic waves, but the cushion 3a is generally made of synthetic resin such as urethane foam and therefore transmits electromagnetic waves, and the cover is also generally made of cloth and therefore transmits electromagnetic waves. Note that the millimeter waves transmitted from the millimeter wave sensor 11, which will be described later, are also reflected by the footrest 2 and the like in the seat 1, but such reflected light does not return to the millimeter wave sensor 11 at a reflection angle other than slight diffuse reflection.

[0017] <Outline of Seat Wetness Detection Device 10> Fig. 16 is a block diagram that schematically shows a wet seat detection device 10 according to this embodiment. As shown in Fig. 16, the wet seat detection device 10 includes a millimeter-wave sensor 11, a reflector 31, and a controller 60. The millimeter-wave sensor 11 and the controller 60 are connected wirelessly or via a wire so as to be able to send and receive signals to and from each other. A display unit 65 and an operation unit 66 are also connected to the controller 60. Here, the millimeter-wave sensor 11 corresponds to the "sensor" of the present invention.

[0018] The millimeter wave sensor 11, which will be described in detail later, includes a transmitter 12 that transmits millimeter waves, which are a type of electromagnetic wave, and a receiver 13 that receives the millimeter waves. Fig. 16 also illustrates the state in which millimeter waves transmitted from the millimeter wave sensor 11 toward the seat 3 (hereinafter referred to as "transmitted waves") are reflected by a reflector 31 (described later) and return as millimeter waves (hereinafter referred to as "reflected waves"). Here, millimeter waves are so-called chirp signals that have a constant frequency, and therefore are represented as sine waves whose magnitude (amplitude) is expressed as a function of time.

[0019] <About millimeter waves> The millimeter waves used in this embodiment are electromagnetic waves with a frequency band of 30 to 300 GHz, which corresponds to a wavelength of 1 to 10 mm, hence the name "millimeter wave" (EHF). Millimeter waves generally have the advantages of being highly linear, being able to be used like a laser, having a wide bandwidth, and being able to pass through various materials such as synthetic resins and cloth. However, as a result of extensive research by the inventors, it has been found that the signal strength of millimeter waves is easily attenuated by moisture.

[0020] In an experiment conducted by the inventors, when millimeter waves (designated as F in FIG. 1) were irradiated onto the seat 3 of the seat 1 using a millimeter wave sensor 11 described below, it was confirmed that the millimeter waves were transmitted directly through the cushion 3a of the seat 3 and reflected by the metal seat frame 30 and footrest 2 inside. When the seat 3 was in a normal, dry state, the reflected waves from the seat frame 30 and the like did not differ much in signal strength from when they were transmitted, but when the seat 3 was wet, a clear attenuation in the signal strength of the reflected waves was confirmed. This demonstrates that millimeter waves have the property of being easily absorbed by moisture.

[0021] <Millimeter wave sensor 11> The millimeter wave sensor 11 is generally a module capable of measuring the distance, direction, and speed of a distant target, but in this embodiment, it is used specifically to measure the signal strength of millimeter waves reflected from the reflector 31, which will be described later. Therefore, the use of the millimeter wave sensor 11 in this embodiment does not require any processing to measure the distance, direction, and speed of the reflector 31, which is fixed in a fixed position. The millimeter wave sensor 11 includes a transmitter 12 that transmits the generated millimeter waves toward the seat 3, and a receiver 13 that receives the millimeter wave signals reflected from the reflector 31.

[0022] More specifically, the millimeter-wave sensor 11 is typically composed of transmitting (TX) and receiving (RX) radio frequency components, analog components such as a synthesizer and a clock, and digital components such as an A / D converter, a digital signal processor (DSP), and a microcomputer (MCU). The millimeter-wave sensor 11 transmits millimeter waves generated by the synthesizer from the TX antenna, and receives reflected waves that are reflected when the transmitted waves hit a target (reflector 31) using the RX antenna. Therefore, in this embodiment, the TX antenna corresponds to the "transmitter 12," and the RX antenna corresponds to the "receiver 13."

[0023] The millimeter wave sensor 11 also has the function of mixing the transmitted wave and the reflected wave in a mixer to generate an IF signal (an intermediate frequency used for calculations), and performing various signal processing based on the data obtained from this IF signal to acquire information such as the position of the target (reflector 31). This allows the millimeter wave sensor 11 to distinguish between reflected waves from auxiliary reflectors 31A and 31B (described later) separately from the reflector 31, and generate electrical signals according to the respective signal intensities. The electrical signals generated here are output to a controller 60 (described later).

[0024] Such a millimeter-wave sensor 11 has the following advantages: it is resistant to environmental changes due to the linearity of millimeter waves, has excellent distance resolution due to the wide bandwidth of millimeter waves, and allows for highly accurate detection due to the short wavelength of millimeter waves, while also enabling the miniaturization of circuits and antennas. One of the advantages of the millimeter-wave sensor 11 is that it can be miniaturized, so it can be configured as a board measuring a few centimeters square overall. Therefore, the millimeter-wave sensor 11 of this embodiment can be disposed in the limited space within the front side portion 4b above the backrest 4, as shown in FIG. 1.

[0025] 2 to 5, a support bracket 50 is fixed to one end of the upper side of the backrest frame 40, and a millimeter-wave sensor 11 is attached to the support bracket 50. By providing the millimeter-wave sensor 11 on the upper side of the backrest 4 at a height that faces downward from the seat 3 in this way, millimeter waves can be emitted from the front toward almost the entire seating surface of the seat 3. The seating surface of the seat 3 refers to the upper, approximately horizontal surface of the entire surface of the cushion 3a that is mainly in contact with the seated person, and corresponds to the area that overlaps with the seat frame 30 in a plan view.

[0026] Furthermore, the angle of the front of the millimeter-wave sensor 11 relative to the seat 3, i.e., the angle at which millimeter waves are emitted toward the seat 3, can be adjusted by the support bracket 50. More specifically, as shown in Fig. 2, an angle bar 42 is fixed along the substantially horizontal upper end 41 of the backrest frame 40, and a support bracket 50 is attached to one end of the angle bar 42 facing toward the outside of the seat. Here, the support bracket 50 is attached at an angle toward the inside of the seat so that its vertical back portion 51 faces a perpendicular line passing through the center of the seat surface of the seat 3.

[0027] <Support bracket 50> 13 to 15, the support bracket 50 includes a rear portion 51 forming a vertical surface, a pair of side portions 52, 52 bent forward at right angles from both end portions of the rear portion 51, and a mounting surface portion 53 supported between the side portions 52 while facing the rear portion 51. The mounting surface portion 53 is a portion on the front side of which the millimeter wave sensor 11 is attached, and is supported so that the angle can be adjusted in the vertical direction.

[0028] That is, the lower edge of the mounting surface portion 53 is rotatably supported via a horizontal rotation shaft 54 ​​that is installed between the side surface portions 52. Meanwhile, a horizontal moving shaft 55 is journaled on the upper edge of the mounting surface portion 53. An arc-shaped guide groove 56 is formed in each side surface portion 52, with the rotation shaft 54 ​​as its center, and both ends of the moving shaft 55 are movably fitted into the guide groove 56 of each side surface portion 52.

[0029] The moving shaft 55 is formed in the shape of a bolt, with one end serving as a bolt head 55a that abuts against the periphery of the guide groove 56 in one side surface portion 52, and the other end being threadedly fitted with a nut 55b that abuts against the periphery of the guide groove 56 in the other side surface portion 52. Therefore, by loosening the nut 55b, the mounting surface portion 53 (i.e., the millimeter-wave sensor 11) can be adjusted to any tilt angle around the rotation axis 54, and by tightening the nut 55b at the desired tilt angle, the mounting surface portion 53 can be fixed at that angle. Note that the specific shape of the millimeter-wave sensor 11 itself to be mounted on the mounting surface portion 53 is well known, so a detailed description thereof will be omitted.

[0030] <Reflector 31> 1 and 2, a reflecting section 31 that also serves as the seat frame 30 is provided below the seat surface of the cushion 3a of the seat 3. The reflecting section 31 is configured to receive millimeter waves transmitted from the millimeter-wave sensor 11 over the entire upper surface side thereof and reflect them toward the millimeter-wave sensor 11. More specifically, as shown in FIGS. 6 to 9, the upper surface section 30a of the seat frame 30 has a plurality of corner reflectors 32 that are integrally and continuously provided as the reflecting section 31, with the open surfaces of the corner reflectors 32 closely spaced on the same plane overlapping the upper surface section 30a.

[0031] As shown in Figure 10, the corner reflector 32 is a reflector made of metal plates in the shape of a right isosceles triangle joined together on three sides. With the corner reflector 32, no matter which side a millimeter wave is incident on, it is reflected repeatedly within the three sides, and the reflected wave can be accurately reflected in the direction from which the millimeter wave was incident. In other words, the corner reflector 32 can broaden the directivity of the reflected wave compared to reflectors of other shapes, and can obtain a uniform reflected wave regardless of the angle of incidence of the millimeter wave. Therefore, even if the millimeter wave sensor 11 is installed above the backrest 4 and the distance is increased, weakening the reflected wave, the reflection efficiency can be increased accordingly.

[0032] 6, the edges of the openings of the multiple corner reflectors 32 are joined together by welding or the like, so that the openings are closely spaced on the same plane, forming the reflective section 31. The reflective section 31 is incorporated as an integral part of the seat frame 30 itself so as to occupy as large an area as possible of the upper surface 30a of the seat frame 30. Note that areas of the upper surface 30a of the seat frame 30 that cannot accommodate the reflective section 31 (multiple corner reflectors 32) are left as they are as a horizontal, plate-like upper surface 30a.

[0033] In this embodiment, the area of ​​the upper surface 30a of the seat frame 30 where the reflector 31 is to be incorporated is hollowed out in advance, and the entire reflector 31, which is made up of multiple connected corner reflectors 32, is incorporated into this area by welding or the like. The reflector 31, which also serves as the seat frame 30 in this way, may be constructed as a separate body and then attached later as part of the seat frame 30, or it may be integrally formed together with the seat frame 30 by sheet metal press forming or casting.

[0034] The specific number and arrangement of the multiple corner reflectors 32 that make up the reflecting section 31 are not limited to the example shown in the figures and are design matters that can be determined as appropriate. As shown in Figures 11 and 12, a predetermined number of corner reflectors 32 (five in the example shown) may be combined in advance, for example, in a linear arrangement, to form a unit that makes up the reflecting section 31. The unit formed by combining five corner reflectors 32 linearly shown in Figures 11 and 12 directly constitutes auxiliary reflecting sections 31A and 31B, which will be described later, separate from the reflecting section 31.

[0035] <Controller 60> 16, the controller 60 is made up of, for example, a microcomputer and peripheral electronic devices, and specifically is configured with a circuit whose main components include a processor (CPU), a non-volatile memory (ROM) for storing programs executed by the processor and various fixed data, and a volatile memory (RAM) for storing data temporarily required for executing the programs, etc. Such controller 60 has, as its functions, an input unit 61, a control unit 62, an output unit 63, a storage unit 64, etc.

[0036] The input unit 61 receives input of various information such as the electrical signal from the millimeter wave sensor 11 and various information such as numerical values ​​designated by the operation unit 66 . The control unit 62 controls the transmission of millimeter waves from the transmitter 12 of the millimeter wave sensor 11 and processes the electrical signal from the millimeter wave sensor 11, thereby detecting wetness of the seat 1 based on the degree to which the signal strength is attenuated by moisture as the millimeter waves pass through the interior of the seat 1 (more precisely, the seat portion 3). A specific method for detecting wetness of the seat portion 3 will be described later.

[0037] The control unit 62 controls the transmission of millimeter waves from the transmitter 12 of the millimeter wave sensor 11 so as to be repeated, for example, at a predetermined cycle. More specifically, the control unit 62 may set the transmitter 12 of the millimeter wave sensor 11 to transmit millimeter waves at a predetermined timing. Here, the predetermined timing may be set as appropriate, for example, immediately before arrival at the next stop where passengers will disembark, or when the train arrives at the terminal station.

[0038] The output unit 63 outputs information about the wetness of the seat 1 detected by the control unit 62. Here, the output destination of the signal from the output unit 63 is mainly the display unit 65, but is not limited to the display unit 65. The memory unit 64 stores programs and various data used by the control unit 62 to detect wetness of the seat 1. The various data include, for example, pre-measured values ​​such as the signal strength of the reflected wave when the seat 1 is dry.

[0039] The display unit 65 displays the determination result of the control unit 62 regarding the wetness of the seat 1. The display unit 65 may be, for example, a personal computer monitor, and displays various information including the determination result in a visually recognizable manner using text, images, etc. In addition to the display by the display unit 65, an audio output device such as a speaker may also be used to notify the user by sound such as an artificial voice or an alarm.

[0040] The operation unit 66 is operated by an operator to input numerical data required for various processes by the control unit 62. The operation unit 66 is, for example, a mouse, keyboard, or touch panel of a personal computer. By operating this operation unit 66, a user of the seat wetness detection device 10 can input various data required for processing by the control unit 62 and issue instructions for processing operations.

[0041] <Operation of the Seat Wetness Detection Device 10> Next, detection of wetness of the seat 1 by the seat wetness detection device 10 will be described. In FIG. 16, the millimeter wave sensor 11 generates millimeter waves using a synthesizer at a predetermined timing based on a command from the control unit 62 of the controller 60, and transmits the millimeter waves from the front side thereof toward the seating surface of the seat 3 below.

[0042] 1, millimeter-wave sensor 11 is located above backrest 4, and therefore the distance from millimeter-wave sensor 11 to seat 3 is greater than when millimeter-wave sensor 11 is located, for example, in a sleeve immediately to the side of seat 3, and therefore a wider irradiation range of millimeter waves onto seat 3 can be secured. Also, in this embodiment, millimeter-wave sensor 11 is located on front side 4b away from the center of backrest 4 so that the seated person does not feel a foreign body sensation in their head when sitting on backrest 4, but it is also possible to irradiate millimeter waves onto the front side of seat 3 from an angle that faces as directly as possible.

[0043] The transmitted wave from the millimeter wave sensor 11 passes through the cushion 3a of the seat 3 and is reflected by the reflecting unit 31, which also serves as the seat frame 30. This reflected wave passes through the cushion 3a again, returns to the millimeter wave sensor 11, and is received by the receiving unit 13. As shown in FIG. 6, the reflecting unit 31 also serves as the seat frame 30. Therefore, compared to when a reflecting unit is provided separately from the seat frame 30, the number of parts and assembly steps can be reduced, and the manufacturing cost of the seat 1 can be reduced.

[0044] Furthermore, the reflecting portion 31 is capable of receiving and reflecting millimeter waves over the entire area of ​​its upper surface, making it possible to detect the wetness over a wide area, such as the entire seat surface of the seat 3. Furthermore, for example, if multiple reflecting plates were locally arranged within the seat 3, it would be necessary to adjust the reflection angle of each reflecting portion, but the reflecting portion 31 of this embodiment eliminates this troublesome work.

[0045] In particular, the reflecting unit 31 is formed by integrally connecting a plurality of corner reflectors 32 so that the opening surfaces of the corner reflectors 32 are closely aligned on the same plane overlapping the upper surface 30a of the seat frame 30. Such a reflecting unit 31 makes it possible to increase the reflection efficiency of the individual corner reflectors 32 over the entire area, and even if the distance from the millimeter wave sensor 11 is increased, a strong reflection intensity can be achieved without angle adjustment compared to a flat reflecting plate.

[0046] When the reflected wave from the reflector 31 returns to and is received by the millimeter-wave sensor 11, the millimeter-wave sensor 11 mixes the transmitted wave and the reflected wave using a mixer to generate an IF signal (intermediate frequency), and performs various signal processing operations based on data obtained from this IF signal. The electrical signal generated by the millimeter-wave sensor 11 is output to the controller 60 and stored in a memory unit 64. The electrical signal stored in the memory unit 64 is converted to digital form by an AD conversion circuit or the like and stored in a memory area within the control unit 62. The control unit 62 executes processing to calculate the signal strength of the reflected wave from the reflector 31 based on the electrical signal captured from the millimeter-wave sensor 11.

[0047] 16(b) is an example of a graph showing the signal strength of the reflected wave from the reflector 31, where the horizontal axis represents the optical distance from the millimeter-wave sensor 11 to the reflector 31, and the vertical axis represents the signal strength of the reflected wave. Here, the distance on the horizontal axis is proportional to the time from the output of the transmitted wave to the return of the reflected wave, and is predetermined by the arrangement of the reflector 31. Furthermore, the signal strength on the vertical axis is expressed as a relative value, and its unit is not particularly limited. The peak of the signal strength of the reflected wave from the reflector 31 occurs at a predetermined point on the horizontal axis depending on the distance from the transmitter 12.

[0048] The chirp of the reflected wave from reflector 31 is subjected to, for example, FFT processing to detect the distance to reflector 31, but since the distance to reflector 31 is fixed, the distance FFT corresponding to the chirp will show a peak at the same point (horizontal axis). Based on the results of this graphing process, control unit 62 determines whether seat 1 is wet. Here, wetness of seat 1 is synonymous with moisture contained mainly in cushion 3a of seat portion 3.

[0049] 17 shows how the millimeter waves from millimeter-wave sensor 11 change when seat 3 is in a normal dry state and when seat 3 has become wet for some reason. The transmission waves from millimeter-wave sensor 11 (transmitter 12) to seat 3 have a large difference in the initial signal strength of the transmitted wave and the signal strength of the reflected wave across the entire upper surface side of reflector 31 between a "dry state" where no moisture is present and a "wet state" where moisture is present.

[0050] The [Concept] in Figure 17 schematically shows a state in which a transmitted wave from the millimeter-wave sensor 11 is reflected by the reflecting portion 31 and returns as a reflected wave. As shown in the [Concept] in Figure 17(a), when the seat 3 is dry, the transmitted wave from the millimeter-wave sensor 11 reaches the reflecting portion 31 without being significantly attenuated as it passes through the cushion 3a, and the reflected wave from the reflecting portion 31 also returns to the millimeter-wave sensor 11 without being significantly attenuated. On the other hand, as shown in the [Concept] in Figure 17(b), when the seat 3 is wet, the transmitted wave from the millimeter-wave sensor 11 reaches the reflecting portion 31 after being significantly attenuated by moisture as it passes through the cushion 3a, and the reflected wave from the reflecting portion 31 also returns to the millimeter-wave sensor 11 after being further attenuated.

[0051] As described above, the millimeter waves emitted from the millimeter wave sensor 11 are significantly weaker when they return to the millimeter wave sensor 11 in a wet state than in a dry state. That is, the inventors have confirmed through experiments that the signal strength of the reflected waves when the seat 3 is in a wet state is significantly smaller than the signal strength of the reflected waves when the seat 3 is in a dry state. Therefore, the control unit 62 can detect the wetness of the seat 1 based on the ratio (signal ratio) between the signal strength of the reflected waves when the seat 3 is in a wet state and the signal strength of the reflected waves when the seat 3 is in a dry state.

[0052] The graph in Fig. 17 shows the signal strength of the reflected wave from the reflector 31. As shown in the graph in Fig. 17(a), when the seat 1 is dry, the peak signal strength of the reflected wave is, for example, 5000 in relative value. On the other hand, as shown in the graph in Fig. 17(b), when the seat 1 is wet, the peak signal strength of the reflected wave is, for example, 2800 in relative value. As such, the signal strength of the reflected wave is attenuated more significantly in the wet state than in the dry state. Specifically, in the numerical example described above, the degree of attenuation in the wet state is 0.56 (2800 / 5000) times that of the dry state, or 44%.

[0053] The signal ratio of 0.56 approaches 1.0 as the seat 1 dries and the amount of moisture decreases, and based on this value, a threshold value between 0.56 and 1.0 is set as the allowable wetness of the seat 1. Specifically, for example, if the threshold value is set to 0.8 based on data from a subjective test to sense "wetness," the seat is determined to be wet when the degree of attenuation of the signal strength of the reflected wave is less than 0.8. Of course, the threshold value of 0.8 is merely an example, and it may be set as appropriate, for example to 0.5.

[0054] Such a threshold value can be set appropriately using the operation unit 66. Specifically, for example, the signal strength can be set to be read at a height Hmm on the vertical axis of the graph. Here, the height Hmm can be set and changed as desired. Furthermore, as will be described later, the height Hmm of the signal strength may be set to have a width of ±w on the horizontal axis, and the average value or the like may be used. This width ±w can also be set and changed as desired. It is also desirable that the timing and frequency YHz for reading the signal strength can be set and changed as desired. Note that the comparison of the peak values ​​of the signal strength does not necessarily require graphing processing.

[0055] It is also preferable that the maximum value (Max) and minimum value (Min) of the signal strength to be read can be arbitrarily changed. In any case, as described above, when the degree of attenuation of the signal strength of the reflected wave becomes less than 1 / X (X>1), a flag is set to indicate that the seat is wet. When this flag is set, it is preferable that the word "wet" or the like is displayed on the display unit 65 as a warning that the seat 1 is wet, as shown in [Monitor] in Fig. 17(b). The subsequent processing will be described later.

[0056] As described above, when calculating the signal ratio of the signal strength of the reflected wave in the wet state and the dry state, the calculation may be performed using the peak value or the average value within a predetermined range ±w, but the following calculation is also possible to reduce errors. That is, the peak of the signal strength may be used as the reference, and as described above, whether the seat 3 is wet may be determined based on the area ratio in a graph within a predetermined range that includes the signal strength within the range ±w on the horizontal axis.

[0057] As another method of determination, a predetermined range may be set on the horizontal axis of the graph that includes the peak of the signal strength of the wave reflected from the reflecting part 31 and a predetermined width before and after it, and whether the seat 3 is wet may be determined based on the area ratio in the graph that falls within this predetermined range. That is, as shown in Fig. 18, whether the seat 3 is wet may be determined based on whether the ratio of the area surrounded by the quadratic curve of the signal strength when the seat 3 is dry to the area surrounded by the quadratic curve of the signal strength when the seat 3 is wet exceeds a predetermined threshold.

[0058] The specific threshold setting is the same as in the case of comparing the numerical values ​​of the peaks. The area of ​​the figure enclosed by the curve or line (horizontal axis, etc.) indicating the signal intensity on the graph can be calculated using a well-known formula, and it is advisable to program the calculation in advance. The area of ​​the region on the graph to be compared can be set by the operation unit 66, similar to the setting of the threshold.

[0059] The determination of such threshold values ​​and predetermined ranges in the graph are design matters that can be appropriately determined based on data from various experiments, simulations, etc. Of course, the comparison based on the area ratio in the graph described above does not necessarily depend on graphical processing, and wetness detection processing may be performed by, for example, comparing values ​​obtained by integrating data on signal strength and distance in the dry and wet states.

[0060] <Response after detecting wetness in seat 3> 19 is a flowchart showing an example of processing after the seat wetness detection device 10 detects that the seat 3 is wet. As described above, when the control unit 62 of the controller 60 detects that the seat 3 is wet (step S101), information relating to the seat number of the wet seat is output to, for example, the driver's cab of the vehicle (step S102).

[0061] Based on this, the information is output to the display of seat 1 (step S103), the information is also output to the conductor's tablet (step S104), and further to a monitor on the ground outside the train (step S111). Furthermore, based on the information output to the monitor on the ground, the inventory status of the replacement part (cushion 3a of seat 3) is confirmed (step S112).

[0062] Next, the conductor checks the actual wetness of the seat 3 of the seat 1 output on the tablet (step S105). At this time, the conductor determines whether or not the seat 3 needs to be replaced (step S106). If the conductor determines that the seat 3 needs to be replaced, he or she requests transportation to the next station where the train stops, in accordance with the aforementioned confirmation of the stock status of the replacement part (step S113). The conductor then receives the replacement part at the next station (step S107), removes the wet seat 3, and replaces it with a new seat 3 (step S108).

[0063] Incidentally, in the detection of wetness of the seat 3 described above, a decision is made based on whether the degree of attenuation of the millimeter wave signal strength exceeds a threshold, and then whether or not the seat 3 actually needs to be replaced is decided manually, for example. However, the necessity of replacement may also be determined automatically. Such control can be implemented relatively easily by changing the program in the controller 60, for example.

[0064] 19, the detection of wetness of the seat 3 may be controlled so that the degree of attenuation of the millimeter wave signal strength is determined based on a plurality of ranks, rather than simply determining whether the degree of attenuation is above or below a threshold. This makes it possible to locally dry lightly wet areas of the seat 3 when the wetness rank is low, without having to replace the entire seat 3.

[0065] <Modification 1 of Reflection Section 31> 20 to 22 show a first modification of the reflecting section 31 according to the embodiment. In this first modified example, in addition to the reflecting part 31 forming the upper surface part of the seat frame 30 described above, a front-end auxiliary reflecting part 31A is added along the front end side of the periphery of the seat frame 30. The front-end auxiliary reflecting part 31A is configured to receive electromagnetic waves transmitted from the millimeter-wave sensor 11 and deviated forward from the reflecting part 31, and to reflect them toward the millimeter-wave sensor 11.

[0066] 11 and 12 are connected together along the front end of the seat frame 30. The connection here may be achieved by welding the corner reflectors 32 together via thin, narrow metal plates, or by directly welding the open ends of the corner reflectors 32 that make up the front end auxiliary reflector 31A. The angle at which the front end auxiliary reflector 31A is connected can be adjusted so that it is bent upward toward the millimeter-wave sensor 11 above the backrest 4 from a state in which it is connected horizontally to the upper surface of the reflector 31.

[0067] In this way, the front-end auxiliary reflecting portion 31A is configured as a separate body from the reflecting portion 31 and is later attached to the seat frame 30, or it may be configured to be provided integrally with the seat frame 30 or the reflecting portion 31 in advance. In such a case, the number of parts and assembly man-hours for the entire seat 1 are reduced. In either configuration, it is preferable that the front-end auxiliary reflecting portion 31A be adjustable to an optimal angle toward the millimeter-wave sensor 11. Note that the specific length and size of the front-end auxiliary reflecting portion 31A, i.e., the number and arrangement of the corner reflectors 32, are design matters that can be determined as appropriate.

[0068] 1, the distance from the seat surface of the seat 3 to the reflector 31 below it is equal to the thickness of the cushion 3a. Therefore, parts of the periphery of the seat (front edge and side edges) located above the irradiation angle of the millimeter-wave sensor 11 to the reflector 31 are outside the transmission and reception route of the millimeter waves. Therefore, by providing a front-end auxiliary reflector 31A on the front edge of the seat frame 30 and expanding the transmission and reception route of the millimeter waves, it becomes possible to detect wetness in the part of the periphery of the seat 3 corresponding to this part without omission.

[0069] As described above, the millimeter wave sensor 11 also has the function of acquiring position information of targets (such as the reflecting portion 31), and therefore can distinguish between the reflected waves from the reflecting portion 31 and the front-end auxiliary reflecting portion 31A and generate electrical signals corresponding to the respective signal intensities. Therefore, when the signal intensities of the reflected waves from each reflecting portion 31, 31A are plotted on the same graph, the peaks of the signal intensity for each reflecting portion 31, 31A appear at different positions on the horizontal axis depending on the distance from the millimeter wave sensor 11, as shown in Fig. 22 for example. This makes it possible to thoroughly and precisely determine the wetness of the seat portion 3 all the way to the front end of the seat surface by comparing the peaks of the signal intensity of the reflected waves described above and comparing the area ratios in the graph for each route within the cushion 3a leading to each reflecting portion 31, 31A.

[0070] <Modification 2 of Reflection Section 31> 23 to 25 show another modified example 2 of the reflecting section 31 according to the embodiment. In this second modification, in addition to the reflecting part 31 and the front-end auxiliary reflecting part 31A described above, a pair of side-end auxiliary reflecting parts 31B1 and 31B2 are added along both sides of the periphery of the seat frame 30. The side-end auxiliary reflecting parts 31B1 and 31B2 are configured to receive electromagnetic waves transmitted from the millimeter-wave sensor 11 and deviated to the side of the reflecting part 31, and to reflect them back towards the millimeter-wave sensor 11.

[0071] 11 and 12 are configured as a unit in a linear arrangement, and are integrally connected along the side edges of the seat frame 30. The side edge auxiliary reflectors 31B1 and 31B2 may be configured as separate bodies from the reflector 31 and attached to the seat frame 30 later, or may be configured to be provided integrally with the seat frame 30 or the reflector 31 in advance. The side edge auxiliary reflectors 31B1 and 31B2 may also be configured so that they can be adjusted to an optimal angle toward the millimeter-wave sensor 11.

[0072] Even when such side end auxiliary reflecting portions 31B1 and 31B2 are added, if the signal strength of the reflected waves from each reflecting portion 31, 31A, 31B1, and 31B2 is plotted on the same graph, as shown in Fig. 25, for example, the signal strength peak for each reflecting portion 31, 31A, 31B1, and 31B2 will appear at different points on the horizontal axis depending on the distance from the millimeter wave sensor 11. This makes it possible to thoroughly and precisely determine the wetness of the seat portion 3 up to the front end and both side ends of the seat surface by comparing the peaks of the signal strength of the reflected waves described above and comparing the area ratios in the graph for each route within the cushion 3a leading to each reflecting portion 31, 31A, 31B1, and 31B2.

[0073] <Configuration and effects of the present invention> Although the present embodiment has been described above, the present invention is not limited to the above-described embodiment. The present invention derived from the above-described embodiment will be described below.

[0074] First, the present invention provides a seat wetness detection device 10 for detecting wetness of a seat 1, a sensor 11 that is provided at a height facing downward the seat portion 3 of the seat 1, transmits electromagnetic waves from the front side toward the seat surface of the opposing seat portion 3, and receives reflected waves of the electromagnetic waves from the front side; A reflecting portion 31 is provided in the seat portion 3 so as to overlap the seat surface in a plan view, and also serves as a seat frame 30 in the seat portion 3. The reflecting portion 31 can receive electromagnetic waves transmitted from the sensor 11 over the entire upper surface side thereof and reflect the waves toward the sensor 11, The wetness of the seat 3 can be determined based on the degree of attenuation of the signal strength of the reflected wave received by the sensor 11 due to moisture.

[0075] According to this type of seat wetness detection device 10, the sensor 11 is disposed at a height that faces downward the seat portion 3 of the seat 1, so that electromagnetic waves can be transmitted from the front side toward the entire seat surface of the seat portion 3. Moreover, the distance from the sensor 11 to the seat surface is relatively long, ensuring a wide irradiation range of the electromagnetic waves.

[0076] Furthermore, since the reflecting portion 31 that reflects the electromagnetic waves from the sensor 11 also serves as the seat frame 30, the number of parts and assembly steps can be reduced, and costs can be reduced, compared to when the reflecting portion 31 is provided separately from the frame of the seat 3. Furthermore, the reflecting portion 31 can receive electromagnetic waves over the entire area of ​​its upper surface and reflect them toward the sensor 11. Therefore, there is no need for the troublesome task of adjusting the reflection angle of the reflecting portion 31.

[0077] In the seat wetness detection device 10, the sensor 11, which is located at a high position, transmits a wave, and the reflected wave is reflected from the reflecting part 31, which covers a wide area of ​​the seat 3. The reflected wave passes through the seat 3, and the wetness of the seat 3 is determined based on the degree to which the signal strength is attenuated by moisture. In this determination, the wetness of the seat 3 can be detected easily and accurately over an even wider area.

[0078] In addition, in the present invention, the seat frame 30 is formed in a panel shape, and the upper surface side of the seat frame 30 is characterized in that a plurality of corner reflectors 32 are integrally connected together as the reflective portion 31, with their opening surfaces closely arranged on the same plane.

[0079] With this type of reflecting portion 31 of the seat frame 30, it is possible to increase the reflection efficiency over the entire area by using individual corner reflectors 32, and even if the distance from the sensor 11 is long, a strong reflection intensity can be achieved without fine adjustment of the angle, etc., compared to a flat reflecting plate.

[0080] The present invention is also characterized by the provision of auxiliary reflecting parts 31A, 31B1, 31B2 which are attached to the reflecting part 31 along at least a portion of the periphery of the seat frame 30, and which are capable of receiving electromagnetic waves transmitted from the sensor 11 and escaping from the reflecting part 31, and reflecting them toward the sensor 11.

[0081] Such auxiliary reflecting portions 31A, 31B1, 31B2 extend outward from the periphery of the seat frame 30, and are therefore able to receive and reflect all electromagnetic waves that pass through the seat 3 but miss the reflecting portion 31. This makes it possible to reliably detect wetness in areas continuing to the ends of the seat surface of the seat 3. The auxiliary reflecting portions 31A, 31B1, 31B2 may be configured separately from the reflecting portion 31 and then attached later as needed, or may be configured integrally with the reflecting portion 31 in advance to reduce the number of parts and assembly man-hours.

[0082] In addition, the present invention is characterized in that the sensor 11 is provided above the backrest 4 supported on the rear end side of the seat portion 3.

[0083] By providing sensor 11 above backrest 4 in this way, the distance from sensor 11 to the seat surface of seat portion 3 is greater than when sensor 11 is provided, for example, on the armrest immediately to the side of seat portion 3, and a wider irradiation range of electromagnetic waves onto seat portion 3 can be secured. Here, it is also possible to irradiate electromagnetic waves onto the seat surface of seat portion 3 from an angle as close as possible to the front side thereof. Furthermore, sensor 11 can be assembled and finished as a single component within the scope of a single seat 1 product.

[0084] In addition, the present invention is characterized in that the sensor 11 is attached to the backrest frame 40 within the backrest 4 via a support bracket 50 that is capable of adjusting the angle of irradiation of electromagnetic waves from the front side toward the seat portion 3. This makes it possible to easily adjust the irradiation range of the electromagnetic waves transmitted from the sensor 11 to overlap the entire seat surface of the seat portion 3, which is located below the front, in accordance with various design specifications of the seat 1.

[0085] In addition, in the present invention, the wetness of the seat 3 is determined by determining whether the ratio of the signal strength of the reflected wave reflected from the reflecting portion 31 and received by the sensor 11 between the peak value when the seat 3 is in a dry state and the peak value when the seat 3 is in a wet state exceeds a predetermined threshold value. By making such a judgment based on a comparison of only the numerical values ​​of the peaks of the signal strength, the wetness of the seat 1 can be judged through extremely simple control.

[0086] In addition, in the present invention, the wetness of the seat 3 is determined by whether or not the ratio of the area surrounded by a quadratic curve representing the signal strength when the seat 3 is in a dry state to the area surrounded by a quadratic curve representing the signal strength when the seat 3 is in a wet state in a graph representing the signal strength of the reflected wave reflected from the reflecting portion 31 and received by the sensor 11 exceeds a predetermined threshold value. According to such a determination based on a comparison of the areas of quadratic curves representing signal strength, the variation in measurement accuracy in determining whether the seat 1 is wet can be reduced, and the accuracy of the detection result can be further improved.

[0087] Furthermore, the present invention is characterized by comprising a display unit 65 for displaying the result of the wetness determination of the seat portion 3. This allows the display unit 65 to easily notify information about the result of the determination of whether the seat 1 is wet. Therefore, anyone who sees the display can more easily take measures to prevent the seat 1 from getting wet.

[0088] Although the present embodiment has been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions that do not depart from the gist of the present invention are also included in the present invention. For example, the seat 1 to be detected by the seat wetness detection device 10 is not necessarily limited to seats installed in the passenger compartment of a railway vehicle, but may also be seats for other vehicles such as airplanes, buses, and ships, or the seat portions of seats installed in movie theaters, theaters, etc.

[0089] Furthermore, the placement position of the millimeter wave sensor 11 is not limited to the backrest 4 of the seat 1, but may also be on the back side of the backrest of another seat placed in front of the seat 1, or on the ceiling or hanging shelf of the vehicle. The electromagnetic waves used in the present invention are not necessarily limited to the millimeter waves. Furthermore, the shapes, sizes, specific locations, angles, and numbers of the reflecting unit 31 and auxiliary reflecting units 31A and 31B are not limited to those in the above-described embodiment, as described above. [Industrial Applicability]

[0090] The present invention is not limited to vehicle seats installed in the passenger compartments of various vehicles such as railway cars, airplanes, automobiles, and ships, but can also be widely applied to seats installed in movie theaters, theatres, etc. [Explanation of symbols]

[0091] 1...Seat 2…Step stool 3… Seat part 4...Backrest 10...Seat wetness detection device 11...Millimeter wave sensor 30...Seat frame 31...Reflector 31A…Front end auxiliary reflector 31B…Side end auxiliary reflector 50...Support bracket 60...Controller 61...Input section 62...Control unit 63...Output section 64...Storage section 65...Display section 66…Operation Department

Claims

1. A seat wetness detection device for detecting wetness of a seat, a sensor that is provided at a height facing downward at the seat portion of the seat, that transmits electromagnetic waves from the front side toward the seat surface of the opposing seat portion, and that receives, from the front side, waves that are reflected back from the electromagnetic waves; A reflective portion is provided in the seat portion so as to overlap the seat surface in a plan view and also serves as a seat frame in the seat portion, the reflecting portion is capable of receiving electromagnetic waves transmitted from the sensor over the entire area of ​​its upper surface side and reflecting the waves toward the sensor, A seat wetness detection device characterized in that it is possible to determine whether the seat is wet based on the degree of attenuation of the signal strength of the reflected wave received by the sensor due to moisture.

2. The seat wetness detection device described in claim 1, characterized in that the seat frame is formed in a panel shape, and the upper surface side of the seat frame has a plurality of corner reflectors arranged integrally with each other so that their opening surfaces are closely aligned on the same plane as the reflective portion.

3. The seat wetness detection device as described in claim 1, characterized in that an auxiliary reflective portion is provided which is attached to the reflective portion along at least a portion of the periphery of the seat frame, and which is capable of receiving electromagnetic waves transmitted from the sensor and escaping from the reflective portion, and reflecting them toward the sensor.

4. 2. The seat wetness detection device according to claim 1, wherein the sensor is provided on an upper side of a backrest supported on a rear end side of the seat portion.

5. The seat wetness detection device according to claim 4, characterized in that the sensor is attached to the backrest frame within the backrest via a support bracket that is adjustable in the angle of irradiation of electromagnetic waves from the front side toward the seat.

6. The seat wetness detection device described in claim 1, characterized in that the wetness of the seat is determined by whether the ratio of the peak value when the seat is dry to the peak value when the seat is wet, for the signal strength of the reflected wave reflected from the reflecting portion and received by the sensor, exceeds a predetermined threshold value.

7. The seat wetness detection device described in claim 1, characterized in that the wetness of the seat is determined by whether or not the ratio of the area surrounded by a quadratic curve representing the signal strength when the seat is dry to the area surrounded by a quadratic curve representing the signal strength when the seat is wet exceeds a predetermined threshold in a graph representing the signal strength of the reflected wave reflected from the reflecting portion and received by the sensor.

8. 8. The seat wetness detection device according to claim 1, further comprising a display unit that displays the result of the seat wetness determination.

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