Sensor system, seat and sensor unit

Abstract

A sensor system has a power feeding device having a power transmission antenna arranged in a vehicle; a cushion body constituting a part of a seat arranged in the vehicle and made of a dielectric material; a sensor provided to the seat; and a power receiving antenna circuit arranged inside the cushion body, receiving power transmission power from the power transmission antenna and outputting power supplied to the sensor.

Description

Technical Field

[0001] This disclosure relates to sensor systems, seats, and sensor units.

[0002] This application claims priority based on Japanese Application No. 2024-047856, filed on March 25, 2024, and incorporates all the contents of the aforementioned Japanese application. Background Technology

[0003] In recent years, in passenger cars and other vehicles, sensors that detect the interior conditions of the vehicle, such as temperature, are sometimes installed to improve the livability of the vehicle interior.

[0004] Powering such sensors via wired connections could complicate wiring and become a major cause of increased cost and weight. Therefore, wireless power supply for the sensors is being considered.

[0005] For example, Patent Document 1 discloses technology related to a wireless power supply system that transmits power via radio waves.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Publication No. 2011-525098 Summary of the Invention

[0009] The sensor system, as an embodiment, includes: a power supply device having a power transmission antenna disposed within a vehicle; a buffer body forming part of a seat disposed within the vehicle and made of a dielectric material; a sensor disposed in the seat; and a power receiving antenna circuit disposed inside the buffer body, receiving power transmitted from the power transmission antenna and outputting power supplied to the sensor. Attached Figure Description

[0010] Figure 1 This is a side view of an example of a vehicle equipped with a sensor system implemented thereon.

[0011] Figure 2 It is a diagram showing the relationship between the sensor system and various parts of the vehicle.

[0012] Figure 3 This is a block diagram representing a structural example of a sensor unit.

[0013] Figure 4 This is a perspective view of the headrest according to the first embodiment.

[0014] Figure 5 This is a cross-sectional view of the headrest.

[0015] Figure 6A This is a cross-sectional view of the sensor unit.

[0016] Figure 6B This is a diagram showing the sensor unit with the cover removed, viewed from the X1 direction.

[0017] Figure 7 This is a cross-sectional view of the sensor unit in a modified example.

[0018] Figure 8 This is a perspective view of the sensor unit in other variations.

[0019] Figure 9 This is a cross-sectional view of the headrest according to the second embodiment.

[0020] Figure 10 This is a diagram used to illustrate the position of the rectifier antenna relative to the headrest.

[0021] Figure 11A It is a graph showing the change in gain of the rectified antenna when the distance L is varied.

[0022] Figure 11B It is a graph showing the change in gain of the rectified antenna when the width W is varied.

[0023] Figure 12 This is a diagram used to illustrate the thickness of the insulating layer within the model of the buffer.

[0024] Figure 13 It is a graph showing the change in gain of the rectified antenna when the thickness of the insulating layer is varied.

[0025] Figure 14A This is a graph representing the pointing characteristics of Comparative Example 1.

[0026] Figure 14B This is a graph representing the pointing characteristics of Example 1.

[0027] Figure 15 This is a cross-sectional view of the headrest of Comparative Example 2.

[0028] Figure 16A This is a graph representing the pointing characteristics of Comparative Example 2.

[0029] Figure 16B This is a graph representing the pointing characteristics of Example 2. Detailed Implementation

[0030] [The problem this disclosure aims to solve]

[0031] In the case of wirelessly powering the sensor, a powered antenna circuit is required to receive the transmitted power and supply power to the sensor.

[0032] The size of the antenna element in this powered antenna circuit depends on the wavelength of the received radio wave. The frequency of the radio wave powered wirelessly ranges from 920 GHz to several GHz. The length of the antenna element used to receive this radio wave is sometimes around 150 mm. In addition, the configuration of the antenna element is sometimes limited by the location of the power transmission antenna.

[0033] Given the limited space inside a vehicle and the constraints on its configuration, it can sometimes be difficult to properly place antenna components within the vehicle.

[0034] This allows for the shortening of antenna elements and the miniaturization of the powered antenna circuit.

[0035] However, in this case, the antenna element becomes omnidirectional, resulting in a reduction in received power.

[0036] Therefore, the purpose of this disclosure is to provide a technique that can improve the received power of a powered antenna circuit.

[0037] [The Effects of This Disclosure]

[0038] According to this disclosure, the receiving power of the powered antenna circuit can be improved.

[0039] [Description of embodiments of this disclosure]

[0040] First, the implementation methods will be described in detail.

[0041] [Summary of Implementation Methods]

[0042] (1) The sensor system of the present disclosure includes: a power supply device having a power transmission antenna disposed in a vehicle; a buffer body constituting part of a seat disposed in the vehicle and made of a dielectric material; a sensor disposed in the seat; and a power receiving antenna circuit disposed inside the buffer body, receiving power from the power transmission antenna and outputting power supplied to the sensor.

[0043] According to the above structure, the receiving antenna circuit is located inside the buffer body. Therefore, the receiving antenna circuit receives radio waves radiated from the transmitting antenna and passing through the buffer body.

[0044] Here, the surface of the cushioning body, which forms part of the seat, is entirely convex, and the cushioning body is made of a dielectric material. Therefore, electromagnetic waves incident on the cushioning body are refracted in a way that concentrates towards the interior of the cushioning body. That is, the cushioning body functions like a dielectric lens.

[0045] Therefore, by appropriately setting the position of the receiving antenna circuit inside the buffer body in a way that increases the gain of the radio waves arriving through the buffer body, the receiving power of the receiving antenna circuit can be improved.

[0046] It should be noted that the sensor system may also include a transmitter for wirelessly transmitting the output of the sensor. With the transmitter, the sensor output can be output to the outside.

[0047] (2) In the sensor system described in (1) above, the buffer may also have: a main body; and an internal space disposed inside the main body to house the powered antenna circuit.

[0048] In this case, the receiving antenna circuit can be easily configured inside the buffer.

[0049] (3) In the sensor system described in (2) above, the internal space may be located near the second surface when the main body has a first surface on the side of the power transmission antenna and a second surface opposite to the first surface.

[0050] In this case, by positioning the internal space closer to the second surface, the thickness of the main body of the buffer between the transmitting antenna and the receiving antenna circuit can be better ensured. As a result, the receiving power of the receiving antenna circuit can be improved more effectively.

[0051] (4) In the sensor system of (2) or (3) above, there may also be an insulating layer between the inner surface of the internal space and the outer surface of the powered antenna circuit, which has a dielectric loss tangent lower than that of the dielectric material.

[0052] In this case, by setting an insulating layer, the power loss caused by the dielectric loss tangent of the buffer can be reduced.

[0053] (5) Alternatively, in the sensor system described in (4) above, when the wavelength of the electromagnetic wave radiated from the transmission antenna is set to λ, the thickness of the insulating layer may be 0.01λ or more and 0.04λ or less.

[0054] When the thickness of the insulating layer is less than 0.02λ, the power loss caused by the buffer becomes relatively large, resulting in a decrease in the received power of the receiving antenna circuit. When the thickness of the insulating layer is greater than 0.05λ, it is found that the effect of the buffer in reducing power loss saturates, and the thickness of the insulating layer becomes unnecessarily large.

[0055] By setting the thickness of the insulation layer to be above 0.02λ and below 0.05λ, the power loss caused by the buffer can be effectively reduced.

[0056] (6) Alternatively, in the sensor system described in (4) or (5) above, the insulating layer may comprise a layer of expanded polystyrene.

[0057] In this case, if expanded polystyrene is placed between the wall of the internal space and the receiving antenna circuit, an insulating layer can be provided.

[0058] (7) Alternatively, in the sensor system described in (4) or (5) above, the insulating layer may include an air layer.

[0059] In this case, if a gap is provided between the inner surface of the internal space and the powered antenna circuit, an insulating layer can be provided.

[0060] (8) Alternatively, in any of the sensor systems described in (4) to (7) above, the sensor system may also include a resin housing that is housed in the internal space, and the insulating layer is defined by housing the powered antenna circuit inside the internal space.

[0061] In this case, by housing the powered antenna circuit in a resin housing, an insulating layer can be easily provided between the inner surface of the internal space and the powered antenna circuit.

[0062] (9) Alternatively, in the sensor system described in (1) above, the antenna substrate may be a flexible substrate when the powered antenna circuit has an antenna element and an antenna substrate on which the antenna element is mounted.

[0063] In this case, the antenna substrate can be deformed according to the shape of the buffer. Therefore, an antenna substrate that deforms in a way that increases the received power of the powered antenna circuit can be placed inside the buffer.

[0064] (10) In any of the sensor systems described in (1) to (9) above, sometimes a portion of the seat includes a headrest.

[0065] In this case, if the power transmission antenna is positioned on the roof side inside the vehicle, the receiving antenna circuit can be positioned close to the power transmission antenna.

[0066] (11) Another implementation from another perspective is a seat disposed within a vehicle. The seat has: a sensor; a buffer body made of a dielectric material; and a receiving antenna circuit disposed inside the buffer body, receiving power from a power transmission antenna disposed within the vehicle and outputting power supplied to the sensor.

[0067] (12) Another implementation from another perspective is a sensor unit disposed in a seat configured in a vehicle. The sensor unit includes: a sensor; a receiving antenna circuit that receives power from a transmitting antenna configured in the vehicle and outputs power supplied to the sensor; and a resin housing having a receiving space inside to house the receiving antenna circuit and disposed inside a buffer body that forms part of the seat and is made of a dielectric material.

[0068] According to the above structure, since it has a resin housing that houses the powered antenna circuit and is disposed inside the buffer body, the powered antenna circuit can be disposed inside the buffer body made of dielectric material.

[0069] This can improve the receiving power of the receiving antenna circuit.

[0070] (13) In the sensor unit of (12) above, if the powered antenna circuit has an antenna substrate, the sensor unit may also have a support member, which is disposed on the inner surface of the receiving space and supports the antenna substrate at a position where a predetermined interval is provided between the antenna substrate and the inner surface.

[0071] In this case, an insulating layer containing an air layer can be provided between the antenna substrate and the resin housing, which can reduce the power loss caused by the buffer.

[0072] (14) In the sensor unit of (13) above, the support member may also include: a circuit board, housed in the housing space; a support column, disposed on the inner surface of the resin housing, supporting the circuit board relative to the inner surface; and a wire, electrically connecting the antenna board to the circuit board.

[0073] In this case, the antenna substrate can be supported by a circuit board, a support column, and wires.

[0074] (15) In the sensor unit of (12) above, the sensor unit may also include a circuit that physically connects the sensor to the resin housing relative to the sensor body and supplies power to the sensor from the resin housing side.

[0075] In this case, the sensor and the resin housing are separated by wiring, so the powered antenna circuit can be placed inside the buffer and the sensor can be placed outside the buffer.

[0076] [Details of the implementation method]

[0077] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings.

[0078] Alternatively, at least some of the embodiments described below can be combined arbitrarily.

[0079] [Regarding the overall structure]

[0080] Figure 1 This is a side view illustrating an example of a vehicle equipped with a sensor system implemented in this way. Figure 1 In the image, a portion of vehicle 1 is cut out to reveal the interior of vehicle compartment 1a.

[0081] exist Figure 1 In this context, vehicle 1 refers to vehicles (passenger cars) including electric vehicles, internal combustion engine vehicles, and hybrid vehicles.

[0082] The sensor system 4 installed in vehicle 1 is a system that detects the state inside vehicle compartment 1a by means of sensors configured inside the compartment 1a.

[0083] The sensor system 4 has a power supply device 6 and multiple sensor units 8. It should be noted that the sensor system 4 sometimes also has only one sensor unit 8. When the sensor system 4 has multiple sensor units 8, the sensor units 8 can be arranged in multiple locations within the vehicle compartment 1a.

[0084] The power supply device 6 is installed on the ceiling surface 1a1 inside the vehicle compartment 1a. The power supply device 6 has a power transmission antenna 6a. The power supply device 6 wirelessly supplies power to multiple sensor units 8 by radiating power supply electromagnetic waves from the power transmission antenna 6a inside the vehicle compartment 1a.

[0085] Multiple sensor units 8 each include sensors for detecting the state inside the vehicle compartment 1a. Each sensor unit 8 has the function of wirelessly transmitting output information representing the sensor's output.

[0086] Furthermore, the sensor unit 8 has the function of receiving electromagnetic waves from the power supply device 6 and converting them into electrical energy. The sensor unit 8 is configured to operate using the power supplied from the power supply device 6. Therefore, the sensor unit 8 can be powered and operated without being wired to other external devices.

[0087] It should be noted that the structure of sensor unit 8 will be described in detail later.

[0088] Multiple sensor units 8 are installed in multiple seats 10 within the cabin 1a.

[0089] Each of the multiple seats 10 has a headrest 12 and a seat portion 11 including a seat and a backrest. In this embodiment, a sensor unit 8 is disposed in the headrest 12. The headrest 12 has the sensor unit 8 built into it. That is, the headrest 12 can also be considered as a sensor in the sensor system 4.

[0090] Vehicle 1 has a power supply 14 and an ECU (Electronic Control Unit) 16.

[0091] Power source 14 is, for example, a secondary battery, which includes lead-acid batteries, lithium-ion batteries, nickel-metal hydride batteries, and capacitors. Power source 14 is the source of power for power supply device 6. Power source 14 is also the source of power supplied to various parts of vehicle 1. In addition, power source 14 can also store electricity generated by alternator or motor.

[0092] ECU16 has the function of performing processing related to the control of various parts of vehicle 1. As described below, the processing includes processing using the output information of sensor unit 8.

[0093] Figure 2 This is a diagram showing the relationship between sensor system 4 and various parts of vehicle 1.

[0094] like Figure 2 As shown, power source 14 is connected to power supply device 6. Power is supplied to power supply device 6 from power source 14. Power supply device 6 generates a power supply signal based on the power supplied from power source 14 and provides it to transmission antenna 6a. Transmission antenna 6a radiates the power supply signal as a power supply electromagnetic wave and transmits it to multiple sensor units 8.

[0095] Multiple sensor units 8 utilize power obtained by receiving electromagnetic waves for power supply to detect the state inside the vehicle compartment 1a and wirelessly transmit output information representing the sensor outputs. The multiple sensor units 8 receive the electromagnetic waves for power supply inside the headrest 12.

[0096] The vehicle 1 also has a receiver 18. The receiver 18 is located inside the vehicle compartment 1a. The receiver 18 receives output information from multiple sensor units 8 and provides the output information to the ECU 16.

[0097] When provided with output information, ECU 16 performs control related to the state within the vehicle compartment 1a based on the output information. For example, ECU 16 controls the air conditioning system installed in vehicle 1 based on the output information.

[0098] Figure 3 This is a block diagram showing a structural example of sensor unit 8.

[0099] like Figure 3 As shown, the sensor unit 8 includes a rectifier antenna 20, a power control circuit 22, a sensor 24, and a transmitter 26.

[0100] The rectifier antenna 20 includes a receiving antenna 20a and a rectifier circuit 20b. The receiving antenna 20a receives electromagnetic waves for power supply from the power supply device 6. The receiving antenna 20a provides an electrical signal based on the received electromagnetic waves to the rectifier circuit 20b. The rectifier circuit 20b rectifies the electrical signal provided from the receiving antenna 20a and converts it into DC power, outputting the converted DC power.

[0101] That is, the rectifier antenna 20 constitutes a power receiving antenna circuit that receives power from the power transmission antenna 6a and outputs power.

[0102] The DC power output from the rectifier circuit 20b is supplied to the power control circuit 22.

[0103] The power control circuit 22 has the function of converting the DC power supplied from the rectifier antenna 20 into a specified voltage and supplying the converted power to the sensor 24 and the transmitter 26. In addition, the power control circuit 22 has the function of storing or discharging the DC power supplied from the rectifier antenna 20 and controlling the power supplied to the sensor 24 and the transmitter 26. The power control circuit 22 can continuously supply power to the sensor 24 and the transmitter 26, or it can periodically supply power to the sensor 24 and the transmitter 26.

[0104] As described above, sensor 24 is a sensor used to detect the state inside the vehicle compartment 1a. More specifically, sensor 24 includes a temperature sensor, a humidity sensor, an acceleration sensor, an illuminance sensor, etc. Sensor 24 has the function of detecting temperature, humidity, acceleration (vibration), illuminance, etc., which are the states inside the vehicle compartment 1a. When sensor 24 is supplied with DC power from the power control circuit 22, it provides an output indicating the detected state inside the vehicle compartment 1a to the transmitter 26.

[0105] The transmitter 26 has a transmitting antenna 26a. The transmitter 26 has the function of wirelessly communicating with the receiver 18 on the vehicle 1 side via the transmitting antenna 26a.

[0106] Transmitter 26 wirelessly transmits the output from sensor 24 as output information. If DC power is supplied from power control circuit 22, transmitter 26 establishes a communication connection with receiver 18 and begins wireless transmission of output information.

[0107] For example, when the main switch of vehicle 1 is turned on, the power supply unit 6 begins to wirelessly supply power to multiple sensor units 8.

[0108] Therefore, multiple sensor units 8 receive power from the power supply unit 6. With power supplied from the power supply unit 6, each sensor unit 8's sensor 24 begins detecting the state within the vehicle compartment 1a and outputting the detection results. Furthermore, the transmitter 26 establishes a communication connection with the receiver 18 and begins wirelessly transmitting information. It should be noted that the transmitter 26 can also begin wirelessly transmitting information while being supplied with DC power, and continue transmitting while power is being supplied.

[0109] The output information sent by transmitter 26 is received by receiver 18 and provided to ECU 16.

[0110] The ECU 16, which is provided with output information, obtains information indicating the state inside the vehicle compartment 1a from the output information. Based on the obtained information indicating the state inside the vehicle compartment 1a, the ECU 16 performs control related to the state inside the vehicle compartment 1a.

[0111] [Regarding the headrest 12 of the first embodiment]

[0112] Figure 4 This is a perspective view of the headrest 12 according to the first embodiment.

[0113] It should be noted that in the following explanation, the three mutually orthogonal directions in each diagram are designated as the X, Y, and Z directions. Additionally, as... Figure 1 As shown, one direction in the X direction is designated as X1, and the opposite direction of X1 is designated as X2. Similarly, one direction in the Y direction is designated as Y1, and the opposite direction of Y1 is designated as Y2. Finally, one direction in the Z direction is designated as Z1, and the opposite direction of Z1 is designated as Z2.

[0114] It should be noted that the X direction is the front-to-back direction, the Y direction is the left-to-right direction, and the Z direction is the up-to-down direction. In addition, the Z1 direction is the up direction, the X1 direction is the direction towards the front of vehicle 1, and the Y1 direction is the direction towards the left when viewed from the front of the vehicle 1.

[0115] The headrest 12 is a pillow-shaped component with rounded corners. The upper surface 12a and lower surface 12b of the headrest 12 are approximately parallel to the Y direction. Furthermore, the upper surface 12a, the front surface 12c on the X1 direction side, the rear surface 12d on the X2 direction side, the left surface 12e on the Y1 direction side, and the right surface 12f on the Y2 direction side of the headrest 12 have convex curved surfaces. It should be noted that the term "convex curved surface" here simply means that the entire object surface is convex; even if the profile of the cross-section between two opposite sides of the object surface is straight, it is sufficient that the profile of the cross-section between the remaining two opposite sides is convex.

[0116] Furthermore, the shape of the headrest 12 is not limited to any particular shape as long as it functions as a headrest. Figure 4 The shape shown.

[0117] Figure 5 This is a cross-sectional view of headrest 12. Figure 5 The image shows a cross-section parallel to the XZ plane.

[0118] The profile of the headrest 12, which is parallel to the XZ plane, has a shape obtained by expanding the sides of the trapezoid outward through a convex curve.

[0119] like Figure 4 and Figure 5 As shown, the headrest 12 includes a sensor unit 8, a frame 28, a buffer body 32, and a cover 34.

[0120] The frame 28 is a component formed from steel tubes or the like into a door shape. The frame 28 has a frame body 28b disposed inside the headrest 12 and a pair of protrusions 28a protruding from the lower surface 12b. The pair of protrusions 28a are inserted into the upper end of the backrest of the seat portion 11 of the seat 10. Thus, the headrest 12 is fixed to the upper end of the backrest.

[0121] The buffer 32 is, for example, a component formed of a dielectric material. In this embodiment, polyurethane is used as the dielectric material. The buffer 32 is elastic. The buffer 32 is a cushioning component when the occupant's head comes into contact with the headrest 12. The buffer 32 forms the overall shape of the headrest 12. Therefore, the buffer 32 is a pillow-shaped component with rounded corners. The upper surface, front surface, rear surface, left surface, and right surface of the buffer 32 have convex curved surfaces.

[0122] Cover 34 covers the outer surface of buffer 32.

[0123] like Figure 5 As shown, the buffer body 32 has a main body 36, a first internal space 38, and a second internal space 40.

[0124] The main body 36 is a component formed of polyurethane, which forms the overall shape of the buffer body 32.

[0125] The interior spaces 38 and 40 are spaces located inside the main body 36.

[0126] The frame body 28b is housed within the first internal space 38. The first internal space 38 is shaped to correspond to the external shape of the frame body 28b. Furthermore, the inner surface of the first internal space 38 abuts against the frame body 28b. Thus, movement of the frame body 28b within the first internal space 38 is restricted. Therefore, the frame body 28b is held inside the buffer body 32. In other words, the buffer body 32 is held within the frame body 28b.

[0127] The sensor unit 8 is housed in the second internal space 40. In this embodiment, the sensor unit 8 has a surface parallel to the YZ plane. This surface is a rectangle with a long side and a short side. Therefore, the sensor unit 8 has a cuboid shape. Consequently, the second internal space 40 is formed into a cuboid shape according to the shape of the sensor unit 8. Furthermore, the inner surface 40a of the second internal space 40 abuts against the sensor unit 8. Thus, the movement of the sensor unit 8 within the second internal space 40 is restricted. As a result, the sensor unit 8 is held inside the buffer body 32.

[0128] It should be noted that, in this embodiment, as Figure 4 As shown, the sensor unit 8 is held inside the buffer body 32 with the short side along the Z direction and the long side along the Y direction.

[0129] In addition, the internal spaces 38 and 40 can be either spaces formed by hollowing out the raw material of the main body 36, or spaces formed by making a cut in the raw material of the main body 36, arranging the frame body 28b and the sensor unit 8 in the cut, and making the cut elastically expand.

[0130] The second internal space 40 is located near the lower surface 36b of the main body 36. Furthermore, the second internal space 40 is located lower than the vertical center of the main body 36.

[0131] Therefore, the sensor unit 8 is held inside the main body 36 at a position close to the lower surface 36b. Furthermore, the sensor unit 8 is held inside the main body 36 at a position lower than the center in the vertical direction.

[0132] [Regarding sensor unit 8]

[0133] Figure 6A This is a cross-sectional view of sensor unit 8. Figure 6A The image shows a cross-section parallel to the XY plane when the sensor unit 8 is positioned on the headrest 12. That is, in... Figure 6A In this section, the various parts of the sensor unit 8 will be described in each direction based on the arrangement of the circuit board 44, bottom surface 46a1, etc. along the YZ plane.

[0134] like Figure 6A As shown, in addition to the rectifier antenna 20, the sensor unit 8 also includes a circuit board 44 and a resin housing 46.

[0135] The resin housing 46 is a cuboid component formed using ABS resin, POM resin, expanded polystyrene, etc. The resin housing 46 includes a housing body 46a and a cover 46b. The resin housing 46 forms the outer shape of the sensor unit 8. Therefore, when the sensor unit 8 is housed in the second internal space 40, the resin housing 46 contacts the inner surface 40a of the second internal space 40.

[0136] The rectifier antenna 20 and the circuit board 44 are housed inside the resin housing 46. That is, the space inside the resin housing 46 is the housing space for accommodating the rectifier antenna 20 and the circuit board 44.

[0137] The circuit board 44 is a rigid substrate for mounting the aforementioned power control circuit 22, sensor 24, and transmitter 26. The circuit board 44 has a rectangular plate shape.

[0138] The circuit board 44 is fixed to the bottom surface 46a1 by the support column 48. The bottom surface 46a1 is the inner surface of the housing body 46a and faces the X1 direction. The bottom surface 46a1 has a rectangular shape. In addition, the bottom surface 46a1 is along the YZ plane.

[0139] The support column 48 is provided so as to protrude from the bottom surface 46a1 of the housing body 46a. The support column 48 supports the circuit board 44 relative to the bottom surface 46a1. At this time, the circuit board 44 is supported along the YZ plane.

[0140] Furthermore, a predetermined interval is provided between the housing body 46a (bottom surface 46a1) and the circuit board 44. Additionally, a predetermined interval is also provided between the cover surface 46b1 of the cover 46b and the circuit board 44. The cover surface 46b1 is the inner surface of the cover 46b and faces the X2 direction. The cover surface 46b1 has a rectangular shape. Furthermore, the cover surface 46b1 is along the YZ plane.

[0141] Figure 6B This is a diagram of sensor unit 8 with cover 46b removed, viewed from the X1 direction.

[0142] like Figure 6B As shown, the rectifier antenna 20 has an antenna substrate 50, a receiving antenna 20a, and a circuit chip 52.

[0143] Circuit chip 52 is a circuit chip that includes rectifier circuit 20b.

[0144] The antenna substrate 50 is a rectangular plate-shaped rigid substrate. The antenna substrate 50 is arranged along the YZ plane.

[0145] The receiving antenna 20a and the circuit chip 52 are mounted on the first surface 50a of the antenna substrate 50. The first surface 50a is the surface on the side of the cover 46b in the antenna substrate 50, and it faces the X1 direction.

[0146] The receiving antenna 20a includes an antenna element 20a1 and a pair of lines 20a2. The antenna element 20a1 and the pair of lines 20a2 are metal foils such as copper foil with patterns formed on the first surface 50a.

[0147] Antenna element 20a1 has a C-shaped loop. Therefore, the receiving antenna 20a of this embodiment constitutes a loop antenna.

[0148] When the sensor unit 8 is disposed inside the headrest 12, the center C of the antenna element 20a1 is located at the center of the headrest 12 in the Y direction. Thus, the antenna element 20a1 is disposed at the center of the headrest 12 in the Y direction.

[0149] A pair of lines 20a2 connect the two ends of the antenna element 20a1 to the circuit chip 52.

[0150] The rectifier antenna 20 of this embodiment has a relatively miniaturized high-impedance loop antenna 20a. The impedance of the receiving antenna 20a is designed to match that of the rectifier circuit 20b.

[0151] Thus, the rectifier antenna 20 of this embodiment is compacted by employing a small, high-impedance loop antenna.

[0152] For example, the diameter of the antenna element 20a1 of the rectifier antenna 20 in this embodiment is several tens of mm. However, since the antenna element 20a1 is small, the rectifier antenna 20 is omnidirectional.

[0153] The circuit chip 52 is connected to the power control circuit 22 mounted on the circuit board 44.

[0154] The antenna substrate 50 and the circuit substrate 44 are electrically connected by a pair of wires 54.

[0155] A pair of wires 54 connect the circuit chip 52 to the power control circuit 22 of the circuit board 44.

[0156] The end of one of the pair of wires 54 on the antenna substrate 50 side is fixed to the end edge on the Y1 direction side of the first surface 50a of the antenna substrate 50. The end of one of the pair of wires 54 on the circuit board 44 side is fixed to the end edge on the Y2 direction side of the substrate surface 44a of the circuit board 44. Thus, the pair of wires 54 connect the end edge of the antenna substrate 50 to the end edge of the circuit board 44.

[0157] Furthermore, a pair of wires 54 support the antenna substrate 50 in such a way that the antenna substrate 50 does not contact the resin housing 46.

[0158] That is, the circuit board 44, the support column 48 and a pair of wires 54 constitute the support member 47. The support member 47 is a member that supports the antenna board 50 in a manner that does not contact the resin housing 46.

[0159] A predetermined interval is provided between the first surface 50a and the cover surface 46b1 of the antenna substrate 50 by means of the support member 47. In addition, a predetermined interval is also provided between the second surface 50b and the bottom surface 46a1 of the antenna substrate 50. The second surface 50b is the surface on the housing body 46a side of the antenna substrate 50, and is the surface facing the X2 direction.

[0160] Therefore, an insulating layer 56 is provided between the rectifier antenna 20 (charge-receiving antenna circuit) and the inner surface 40a of the second internal space 40. Figure 6A The insulating layer 56 is an air layer.

[0161] Thus, the resin housing 46 is housed in the second internal space 40, and the insulating layer 56 is defined by housing the rectifier antenna 20 inside.

[0162] The system 4 of this embodiment includes a resin housing 46. Therefore, if the rectifier antenna 20 is housed in the resin housing 46, an insulating layer 56 can be easily provided between the inner surface 40a of the second internal space 40 and the rectifier antenna 20.

[0163] As described above, the insulating layer 56 is an air layer. Therefore, the dielectric loss tangent of the insulating layer 56 is lower than that of the polyurethane used as the raw material for the buffer 32.

[0164] Therefore, for example, compared to the case where the rectifier antenna 20 and the main body 36 of the buffer 32 are in direct contact, the loss of received power of the rectifier antenna 20 due to the dielectric loss tangent of the buffer 32 can be reduced.

[0165] Furthermore, when the wavelength of the radio wave radiated from the transmission antenna 6a is set to λ, the thickness t of the insulating layer 56 is sometimes set to be greater than 0.02λ and less than 0.05λ. It should be noted that the thickness t includes the thickness t1 of the first surface 50a and the cover surface 46b1, and the thickness t2 of the second surface 50b and the bottom surface 46a1. The insulating layer 56 is present at least on the outer surface of the antenna substrate 50 (the first surface 50a and the second surface 50b).

[0166] When the thickness t is less than 0.02λ, the power loss caused by the buffer 32 becomes relatively large, resulting in a decrease in the received power of the rectifier antenna 20. When the thickness t is greater than 0.05λ, the effect of reducing power loss caused by the buffer 32 is saturated, the thickness of the resin shell 46 becomes unnecessarily large, and it is difficult to properly configure it within the headrest 12.

[0167] By setting the thickness t to be above 0.02λ and below 0.05λ, the power loss caused by the buffer 32 can be effectively reduced. Furthermore, the resin housing 46 can be made more compact, making it easier to properly position it within the headrest 12.

[0168] According to the above structure, the rectifier antenna 20 (receiving antenna circuit) is disposed inside the buffer body 32. Therefore, the rectifier antenna 20 receives radio waves radiated from the transmission antenna 6a and passing through the buffer body 32.

[0169] Here, the surface of the headrest 12's cushion 32 is entirely convex, and the cushion 32 is made of a dielectric material. Therefore, electromagnetic waves incident on the cushion 32 are refracted in a way that concentrates towards the interior of the cushion 32. That is, the cushion 32 functions like a dielectric lens.

[0170] Therefore, by appropriately setting the position of the rectifier antenna 20 inside the buffer 32 in a way that increases the gain of the radio waves arriving through the buffer 32, the receiving power of the rectifier antenna 20 can be improved.

[0171] Furthermore, according to the above structure, the receiving power of the rectifier antenna 20 can be increased, thereby suppressing the transmitted power in the power supply device 6 and improving the power economy of the vehicle 1 equipped with this system 4. Moreover, interference to other wireless communication systems besides this system 4 can be reduced.

[0172] In addition, the buffer body 32 of this embodiment has a main body 36 and a second internal space 40, so the sensor unit 8 containing the rectifier antenna 20 can be easily arranged inside the buffer body 32.

[0173] In addition, in this embodiment, the power transmission antenna 6a is positioned directly above the headrest 12 in the ceiling surface 1a1.

[0174] Therefore, the upper surface 36a (first surface) of the main body 36 is located on the side of the transmission antenna 6a. The lower surface 36b (second surface) of the main body 36 is opposite to the upper surface 36a. The second internal space 40 is located closer to the lower surface 36b than the upper surface 36a.

[0175] This ensures a greater thickness of the main body 36 between the transmission antenna 6a and the rectifier antenna 20. As a result, the receiving power of the rectifier antenna 20 can be improved more effectively.

[0176] In addition, the buffer 32 in this embodiment is configured as a headrest 12 as part of the seat 10, so that the rectifier antenna 20 and the power transmission antenna 6a can be arranged close to each other.

[0177] It should be noted that in this embodiment, the insulating layer 56 is exemplified as an air layer. However, the insulating layer 56 only needs to have a dielectric loss tangent lower than that of the polyurethane used as the raw material for the buffer 32. Therefore, the insulating layer 56 can also be, for example, a expanded polystyrene layer. The dielectric loss tangent of the expanded polystyrene layer is lower than that of the polyurethane. Therefore, when the insulating layer 56 is a expanded polystyrene layer, the power loss of the rectifier antenna 20 caused by the dielectric loss tangent of the buffer 32 can also be reduced.

[0178] Additionally, when the insulating layer 56 is a expanded polystyrene layer, such as Figure 7 As shown, the insulating layer 56 can be composed of a first component 56a and a second component 56b.

[0179] The first component 56a and the second component 56b are components formed of expanded polystyrene. The first component 56a is disposed on the X2 direction side of the rectifier antenna 20 and abuts against the second surface 50b of the antenna substrate 50. The second component 56b is disposed on the X1 direction side of the rectifier antenna 20 and abuts against the first surface 50a of the antenna substrate 50.

[0180] The rectifier antenna 20 and the circuit board 44 are held together by being sandwiched between the first component 56a and the second component 56b.

[0181] In this case, the insulating layer 56 contacts the inner surface 40a of the second internal space 40 and the rectifier antenna 20. Therefore, the sensor unit 8 with the insulating layer 56 can be constructed without using the aforementioned resin housing 46. In this way, by omitting the resin housing 46, the structure of the sensor unit 8 can be simplified.

[0182] Furthermore, the example shown is of a sensor unit 8 in this embodiment where the resin housing 46 houses the rectifier antenna 20 and the sensor 24. However, the sensor 24 may also be disposed outside the resin housing 46.

[0183] For example, such as Figure 8 As shown, the sensor unit 8 may also include a line 60 connecting the sensor 24 to the resin housing 46. The rectifier antenna 20 and the circuit board 44 are housed within the resin housing 46. A power control circuit 22 other than the sensor 24 and a transmitter 26 are mounted on the circuit board 44. The line 60 is used to supply power to the sensor 24 from the resin housing 46 side, or to provide the output of the sensor 24 to the resin housing 46 side.

[0184] In this configuration, the sensor 24 and the resin housing 46 are separate components. The sensor 24 and the resin housing 46 are physically connected via a wire 60. Therefore, the rectifier antenna 20 can be positioned inside the buffer body 32, and the sensor 24 can be positioned outside the buffer body 32. As a result, the sensor 24 can be positioned in a more suitable environment for detecting the state inside the vehicle compartment 1a, thus improving the accuracy of the sensor 24.

[0185] [Regarding the headrest 12 of the second embodiment]

[0186] Figure 9 This is a cross-sectional view of the headrest 12 according to the second embodiment.

[0187] The difference between this embodiment and the first embodiment is that the antenna substrate 50 included in the rectifier antenna 20 is an FPC (Flexible Printed Circuits), and the rectifier antenna 20 is bent. Furthermore, the difference between the sensor unit 8 in this embodiment and the first embodiment is that it includes a resin housing 62 that houses the circuit board 44, and the rectifier antenna 20 and the resin housing 62 containing the circuit board 44 are separate components.

[0188] In this embodiment, the second internal space 40 is located near the upper surface 36a of the main body 36. Furthermore, the second internal space 40 is curved along the shape of the upper surface 36a.

[0189] Therefore, the rectifier antenna 20 is held inside the main body 36 near the upper surface 36a. Furthermore, the rectifier antenna 20 is held above the frame body 28b (frame 28). Further, the antenna substrate 50 of the rectifier antenna 20 is bent along the shape of the upper surface 36a according to the shape of the second internal space 40.

[0190] An insulating layer 56 is disposed between the rectifier antenna 20 and the inner surface 40a of the second internal space 40. The insulating layer 56 is a expanded polystyrene layer. The insulating layer 56 is formed by a first member 56a and a second member 56b made of expanded polystyrene. The rectifier antenna 20 is held between the first member 56a and the second member 56b. The first member 56a and the second member 56b are bent according to the shape of the second internal space 40 in a manner that follows the shape of the upper surface 36a. Therefore, the first member 56a and the second member 56b bend the antenna substrate 50 and hold the antenna substrate 50.

[0191] As described above, the sensor unit 8 of this embodiment includes a resin housing 62 that houses the circuit board 44. The resin housing 62 is housed within a third internal space 41. The third internal space 41 is a space provided on the rear surface 36d side of the main body 36. The third internal space 41 is exposed on the rear surface 36d.

[0192] Therefore, the resin housing 62 housed in the third internal space 41 is also exposed. As a result, the sensor 24 mounted on the circuit board 44 is positioned in a more suitable environment for detecting the state inside the vehicle compartment 1a. Consequently, the accuracy of the sensor 24 can be improved.

[0193] The resin housing 62 and the rectifier antenna 20 are connected by line 64. The DC power output by the rectifier antenna 20 is supplied to various parts mounted on the circuit board 44 via line 64.

[0194] In this embodiment, the antenna substrate 50 is an FPC, so the antenna substrate 50 can be deformed according to the shape of the buffer 32 (main body 36). Therefore, the antenna substrate 50, which can be deformed in a way that increases the received power of the rectifier antenna 20, can be disposed inside the buffer 32.

[0195] In addition, in this embodiment, the rectifier antenna 20 is held near the upper surface 36a of the main body 36, so it can be configured closer to the power transmission antenna 6a.

[0196] 〔other〕

[0197] In the above embodiments, the example is that the sensor unit 8 is provided only in the headrest 12 of the seat 10, but it is sufficient to provide the sensor unit 8 inside the buffer body that constitutes part of the seat 10. More specifically, the sensor unit 8 may also be provided in the seat portion and backrest of the seat portion 11 of the seat 10 that has a buffer body made of dielectric material.

[0198] Furthermore, in the above embodiments, the sensor unit 8 is shown to be located at a higher or lower position on the buffer body 32. However, the sensor unit 8 can be disposed within the main body 36 of the buffer body 32, thereby improving the receiving power of the rectifier antenna 20.

[0199] In addition, in the above embodiments, the main body 36 of the buffer 32 is exemplified as being formed of polyurethane, but dielectric materials other than polyurethane may also be used.

[0200] In the first embodiment described above, the antenna substrate 50 of the rectifier antenna 20 is arranged along the YZ plane, but the antenna substrate 50 can be arranged along either the XY plane or the XZ plane. In this case, similarly to the first embodiment, the received power of the rectifier antenna 20 can be improved.

[0201] Furthermore, in the above embodiments, the case where the receiving antenna 20a of the rectifier antenna 20 is configured as a loop antenna is illustrated, but the receiving antenna 20a may also be a dipole antenna, a planar antenna, or other antennas.

[0202] [Regarding verification experiments]

[0203] Next, the verification test conducted on the effectiveness of System 4 will be explained.

[0204] As an experimental method, models of the headrest 12 and rectifier antenna 20 of this system 4 were constructed, and the numerical values ​​of the evaluation objects were obtained through computer simulation and evaluated. The contents of the four experiments implemented are shown below.

[0205] Experiment 1: Verification of the optimal position of the rectifier antenna 20 relative to the headrest 12

[0206] Experiment 2: Verification of the thickness of insulation layer 56

[0207] Experiment 3: Evaluation of the pointing characteristics of the rectified antenna 20 of the first embodiment

[0208] Experiment 4: Evaluation of the pointing characteristics of the rectified antenna 20 of the second embodiment

[0209] [Regarding Experiment 1]

[0210] In Experiment 1, using a model of the headrest 12 of the first embodiment, the change in gain of the rectifier antenna 20 when its relative position to the headrest 12 changes was determined. In Experiment 1, the gain when powered by radio waves at a frequency of 920 MHz was also determined.

[0211] It should be noted that the power transmission antenna 6a is located directly above the headrest 12 in the Z direction.

[0212] Figure 10 This is a diagram illustrating the position of the rectifier antenna 20 relative to the headrest 12. Figure 10 In this context, distance L is the distance in the Z direction from the upper surface 12a (upper surface 36a) to the center C of antenna element 20a1. Width W is the dimension in the Y direction of headrest 12 (buffer 32). It should be noted that the diameter D of antenna element 20a1 of rectifier antenna 20 is set to 40mm, and the maximum dimension in the X direction of headrest 12 is set to 30mm.

[0213] In Experiment 1, the change in gain of the rectifier antenna 20 when the distance L and width W are varied is determined by simulation.

[0214] With the distance L varying, the width W is set to 150mm.

[0215] Furthermore, the position of the rectifier antenna 20 in the X direction is set as follows: First, the rectifier antenna 20 is positioned at the center of the headrest 12 in the X direction, and the distance L at which the gain of the rectifier antenna 20 is maximized is determined. Then, with the distance L fixed, the position of the rectifier antenna 20 in the X direction at which the gain of the rectifier antenna 20 is maximized is determined. This determined position is used as the reference position of the rectifier antenna 20 in the X direction, and the distance L and width W are varied accordingly.

[0216] With the width W varying, the distance L is set to 130mm.

[0217] Figure 11A This is a graph showing the change in gain of the rectifier antenna 20 as the distance L varies. Figure 11A In the diagram, the horizontal axis represents distance L, and the vertical axis represents gain.

[0218] exist Figure 11A In the diagram, curve g1 represents the change in gain of the Y-direction component in the Z-axis direction. Curve g2 represents the change in gain of the X-direction component in the Z-axis direction. Curve g3 represents the gain of the rectifier antenna 20 when there is no surrounding buffer 32. The position of the rectifier antenna 20 when there is no surrounding buffer 32 is the same as the position of the rectifier antenna 20 disposed within the headrest 12 in the first embodiment.

[0219] like Figure 11A As shown, if the distance L is 80mm or more, the gain in the Y direction is higher than the gain of the rectifier antenna with 20 individual units.

[0220] Additionally, when the distance L is less than 130mm, the gain in the X direction is lower than the gain of a single rectifier antenna (20 units).

[0221] However, when the distance L is greater than 130mm, the gain in the X direction is higher than the gain of the rectifier antenna with 20 individual units.

[0222] Figure 11B This is a graph showing the change in gain of the rectified antenna 20 when the width W is varied. Figure 11B In the diagram, the horizontal axis represents the width W, and the vertical axis represents the gain.

[0223] exist Figure 11B In the diagram, curve g4 represents the gain change in the Y direction. Curve g5 represents the gain change in the X direction. Curve g6 represents the gain when the rectifier antenna 20 is configured in the same position.

[0224] In Experiment 1, such as Figure 11B As shown, if the width W is 100mm or more, the gain in the Y direction is higher than that of a single rectifier antenna (20 units).

[0225] Additionally, when the width W is less than 150mm, the gain in the X direction is lower than the gain of a single rectified antenna (20 units).

[0226] However, when the width W is greater than 150mm, the gain in the X direction is higher than the gain of the rectified antenna with 20 individual units.

[0227] Therefore, if the rectifier antenna 20 is placed inside the headrest 12 (buffer 32), the gain (received power) of the rectifier antenna 20 will be increased.

[0228] Furthermore, it can be seen that if the distance L is greater than 130mm, the gain of the rectifier antenna 20 will be further improved.

[0229] Furthermore, it can be seen that if the width W is greater than 150mm, the gain of the rectifier antenna 20 will be further improved.

[0230] [Regarding Experiment 2]

[0231] In Experiment 2, using a simulated buffer model, the change in gain of the rectifier antenna 20 was determined when the thickness t of the insulating layer 56 was varied. In Experiment 2, the thickness t of the portion of the insulating layer 56 facing the outer surface (first surface 50a and second surface 50b) of the antenna substrate 50 was varied.

[0232] Figure 12 This is a diagram used to illustrate the thickness t of the insulating layer 56 within the model of the buffer.

[0233] The buffer model R has a main body 100 and an internal space 140. The main body 100 corresponds to the main body 36 of the headrest 12. The main body 100 has a cubic shape with one side measuring 200 mm. In addition, the internal space 140 corresponds to the second internal space 40 of the headrest 12. Therefore, the rectifier antenna 20 is housed in the internal space 140.

[0234] An insulating layer 56 is disposed between the rectifier antenna 20 (antenna substrate 50) and the inner surface 140a of the internal space 140.

[0235] In Experiment 2, insulating layer 56 was set as an air layer. Additionally, in Experiment 2, as... Figure 12 As shown, the resin housing 46 is omitted, and only an insulating layer 56 (air layer) exists between the inner surface 140a and the first surface 50a (second surface 50b) of the antenna substrate 50.

[0236] In addition, the frequency of the radio waves used for power supply from the transmission antenna 6a is set to 920 MHz.

[0237] Figure 13 This is a graph showing the change in gain of the rectifier antenna 20 as the thickness t of the insulating layer 56 varies. Figure 13 In the diagram, the horizontal axis represents the thickness t of the insulating layer 56, and the vertical axis represents the gain. Additionally, Figure 13 The dashed line in the diagram represents the gain level of the 20-unit rectifier antenna. The gain of the 20-unit rectifier antenna is 1.21.

[0238] like Figure 13 As shown, when the thickness t is 0 (with the buffer 32 in contact with the rectifier antenna 20), the gain is 0.25 dBi. However, as the thickness t increases, the gain increases, asymptotically approaching the gain of the rectifier antenna 20 as a single unit. With a thickness t of 4 mm, the gain is approximately 1 dBi. Furthermore, if the thickness t exceeds 10 mm, the gain becomes sufficiently close to the gain of the rectifier antenna 20 as a single unit. That is, if the thickness t exceeds 10 mm, the gain saturates.

[0239] Therefore, if the thickness t is 4 mm or more and 10 mm or less, it can be said that the loss of received power of the rectifier antenna 20 caused by the buffer 32 can be reduced.

[0240] Here, if we denote the thickness t as λ, representing the wavelength of the electromagnetic wave used for power supply, then the frequency of the power supply is 920 MHz, and therefore 4 mm is represented as 0.012λ. Similarly, 10 mm is represented as 0.04λ.

[0241] That is, according to the results of Experiment 2, by setting the thickness t to be above 0.01λ and below 0.04λ, the power loss caused by the buffer body 32 can be effectively reduced.

[0242] [Regarding Experiment 3]

[0243] In Experiment 3, using a model of the headrest 12 of the first embodiment, the rectifier antenna 20 (sensor unit 8) with a distance L of 35 mm, a width W of 180 mm, and a thickness t of the insulating layer 56 of 2 mm was used as Example 1, and the rectifier antenna 20 without the surrounding buffer 32 was used as Comparative Example 1. The pointing characteristics of the two were compared. The position of the rectifier antenna 20 without the surrounding buffer 32 was the same as that of the rectifier antenna 20 in Example 1.

[0244] Figure 14A This is a graph representing the pointing characteristics of Comparative Example 1. Figure 14B This is a graph representing the pointing characteristics of Example 1. Figure 14A and Figure 14B In the diagram, arrow Z represents the Z1 direction, and arrow X represents the X1 direction.

[0245] Figure 14A and Figure 14BThis indicates the pointing characteristics of the polarization component along the X direction (hereinafter also referred to as the X-axis component) in the XZ plane, and the pointing characteristics of the polarization component along the Y direction (hereinafter also referred to as the Y-axis component) in the XZ plane.

[0246] exist Figure 14A In the diagram, curve g7 represents the directional characteristics of the Y-axis component, and curve g8 represents the directional characteristics of the X-axis component. Curves g7 and g8 are repeated.

[0247] Figure 14B In the diagram, curve g9 represents the directional characteristics of the Y-axis component, and curve g10 represents the directional characteristics of the X-axis component.

[0248] like Figure 14B As shown, the pointing characteristics of Example 1 are improved in the Z1 direction compared to those of Comparative Example 1. That is, the pointing characteristics of Example 1 are found to be improved in the direction toward the transmission antenna 6a.

[0249] More specifically, in Figure 14B In the example, the gain in the Z1 direction of the X-axis component is compared with the gain in Comparative Example 1. Figure 14A Compared to [previous data], this represents an improvement of approximately 3 dB. Additionally, in [previous data]... Figure 14B In the comparison example 1, the gain in the Z1 direction of the Y-axis component was increased by about 1 dB.

[0250] Based on the above results, it can be seen that the receiving power of the rectifier antenna 20 is improved in Example 1.

[0251] In addition, such as Figure 14B As shown, the rectifier antenna 20 of Embodiment 1 can receive both the X-axis component and the Y-axis component.

[0252] [Regarding Experiment 4]

[0253] In Experiment 4, the rectifier antenna 20 using the headrest 12 model of the second embodiment was designated as Example 2, and the rectifier antenna 20 without a curved shape was designated as Comparative Example 2. The pointing characteristics of the two were compared.

[0254] Figure 15 This is a cross-sectional view of the headrest 12 of Comparative Example 2. Figure 15 The sensor unit 8 shown is... Figure 9 The sensor unit 8 of the second embodiment shown is different only in that the rectifier antenna 20 is planar along the XY plane and does not have a curved shape.

[0255] Figure 16A This is a graph representing the pointing characteristics of Comparative Example 2. Figure 16B This is a graph representing the pointing characteristics of Example 2. Figure 16A and Figure 16B In the diagram, arrow Z represents the Z1 direction, and arrow X represents the X1 direction.

[0256] like Figure 16B As shown, the pointing characteristics of Example 2 are improved in the Z1 direction compared to those of Comparative Example 2. That is, the pointing characteristics of Example 2 are found to be improved in the direction toward the transmission antenna 6a.

[0257] More specifically, in Figure 16B In the comparison, the gain in the Z1 direction is compared with the gain in Comparative Example 2. Figure 16A Compared to the previous version, it improved by about 1 dB.

[0258] In addition, Figure 16B In the range of 60 degrees on both sides centered on the Z1 direction, the gain is compared with that of Comparative Example 2. Figure 16A Compared to Example 2, the gain is improved.

[0259] Based on the above results, it can be seen that in Embodiment 2, the receiving power of the rectifier antenna 20 is greatly improved in the front-to-back direction.

[0260] 〔Summarize〕

[0261] It should be noted that the embodiments disclosed herein are illustrative in all respects, and not restrictive.

[0262] The scope of this invention is not as described above, but is indicated by the scope of the claims, and is intended to include all modifications within the scope of the claims.

[0263] Explanation of reference numerals in the attached figures

[0264] 1 vehicle

[0265] 1a car room

[0266] 1a1 ceiling surface

[0267] 4-sensor system

[0268] 6 Power Supply Units

[0269] 6A transmission antenna

[0270] 8 sensor units

[0271] 10 seats

[0272] 11 Seating Section

[0273] 12 headrests

[0274] 12a upper surface

[0275] 12b lower surface

[0276] 12c front surface

[0277] Surface after 12 days

[0278] 12e left surface

[0279] 12f right surface

[0280] 14 power supplies

[0281] 16 ECU

[0282] 18 receivers

[0283] 20 rectifier antenna (power receiving antenna circuit)

[0284] 20A receiving antenna

[0285] 20a1 antenna element

[0286] 20a2 line

[0287] 20b rectifier circuit

[0288] 22 Power Control Circuit

[0289] 24 sensors

[0290] 26 transmitters

[0291] 26a transmitting antenna

[0292] 28 frames

[0293] 28a protrusion

[0294] 28b main frame

[0295] 32 buffers

[0296] 34 masks

[0297] 36 main body sections

[0298] 36a upper surface

[0299] 36b lower surface

[0300] 36d post-surface

[0301] 38 First Interior Space

[0302] 40 Second interior space

[0303] 40a inner surface

[0304] 41 Third Interior Space

[0305] 44 circuit board

[0306] 44a substrate surface

[0307] 46 Resin Housing

[0308] 46a shell body

[0309] 46a1 bottom surface

[0310] 46b cover

[0311] 46b1 cover

[0312] 47 Supporting components

[0313] 48 pillars

[0314] 50 antenna substrate

[0315] 50a First Page

[0316] 50b second side

[0317] 52 circuit chip

[0318] 54 wire

[0319] 56 insulation layers

[0320] 56a First Component

[0321] 56b Second Component

[0322] Route 60

[0323] 62 Resin Housing

[0324] Route 64

[0325] 100 main body

[0326] 140 interior space

[0327] 140a inner surface

[0328] Center C

[0329] D diameter

[0330] L distance

[0331] W width

[0332] Curves g1, g2, g3, g4, g5, g6, g7, g8, g9, g10

[0333] Thicknesses t, t1, and t2.

Claims

1. A sensor system, comprising: The power supply unit has a power transmission antenna installed inside the vehicle; The buffer body, which forms part of the seat disposed in the vehicle, is made of a dielectric material; Sensors are installed in the seat; and The receiving antenna circuit is disposed inside the buffer body, receives the power transmitted from the transmitting antenna, and outputs the power supplied to the sensor.

2. The sensor system according to claim 1, wherein, The buffer body has: Main body; and An internal space, located inside the main body, houses the powered antenna circuit.

3. The sensor system according to claim 2, wherein, The main body has a first surface on the side of the power transmission antenna and a second surface opposite to the first surface. The internal space is located near the second surface.

4. The sensor system according to claim 2 or 3, wherein, An insulating layer is also provided between the inner surface of the internal space and the outer surface of the powered antenna circuit, the dielectric loss tangent of the insulating layer being lower than that of the dielectric material.

5. The sensor system according to claim 4, wherein, When the wavelength of the radio wave radiated from the transmission antenna is set to λ, the thickness of the insulating layer is 0.01λ or more and 0.04λ or less.

6. The sensor system according to claim 4 or 5, wherein, The insulating layer comprises a layer of expanded polystyrene.

7. The sensor system according to claim 4 or 5, wherein, The insulating layer includes an air layer.

8. The sensor system according to any one of claims 4 to 7, wherein, The sensor system also includes a resin housing housed within the internal space, with the insulating layer defined by housing the powered antenna circuitry within it.

9. The sensor system according to claim 1, wherein, The powered antenna circuit has the following features: Antenna elements; and Antenna substrate, on which the antenna element is mounted. The antenna substrate is a flexible substrate.

10. The sensor system according to any one of claims 1 to 9, wherein, A portion of the seat includes a headrest.

11. A seat, configured in a vehicle, wherein, The seat has: sensor; The buffer is made of dielectric material; and The receiving antenna circuit, disposed inside the buffer body, receives power from the transmitting antenna disposed inside the vehicle and outputs power to the sensor.

12. A sensor unit disposed in a seat configured within a vehicle, wherein, The sensor unit includes: sensor; The receiving antenna circuit receives power from the transmitting antenna configured in the vehicle and outputs power supplied to the sensor. and The resin housing has an internal space for housing the powered antenna circuitry and is disposed inside a buffer body that forms part of the seat and is made of a dielectric material.

13. The sensor unit according to claim 12, wherein, The powered antenna circuit has an antenna substrate. The sensor unit also includes a support member disposed on the inner surface of the receiving space, which supports the antenna substrate at a position where a predetermined interval is provided between the antenna substrate and the inner surface.

14. The sensor unit according to claim 13, wherein, The support member also includes: A circuit board is housed in the housing space; A support column, disposed on the inner surface of the resin housing, supports the circuit board relative to the inner surface; and A wire is used to electrically connect the antenna substrate to the circuit board.

15. The sensor unit according to claim 12, wherein, The sensor unit also includes wiring that physically connects the sensor to the resin housing, which is separate from the sensor, and supplies power to the sensor from the resin housing side.

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