Roof structure for vehicle and conductor plate

Abstract

The invention relates to a roof structure of a vehicle and a conductor plate. A vehicle roof structure in which a space in which a second antenna and a communication module having a first antenna and a base substrate are disposed is formed between a roof panel and a roof liner, and a non-conductive roof panel cover is disposed above the space. A conductor plate on which the communication module and the second antenna can be mounted is disposed below the space, and an opening is provided in at least a portion of a portion of the conductor plate facing the base substrate.

Description

TECHNICAL FIELD

[0001] The present application relates to wireless communication. BACKGROUND

[0002] A system in which a computer mounted on a vehicle performs wireless communication is becoming widespread. In association therewith, for example, in Japanese Patent Application Publication No. 2022-157613, a technique related to a configuration position of a communication antenna mounted on a vehicle is disclosed. SUMMARY

[0003] An object of the present disclosure is to improve the transmission efficiency of a wireless signal.

[0004] An aspect of an embodiment of the present disclosure is a roof structure of a vehicle in which a space in which a communication module having a first antenna and a base substrate, and a second antenna are arranged is formed between a roof panel and a roof liner, wherein

[0005] A roof panel cover of a non-conductive body is arranged above the space, a conductive body plate in which the communication module and the second antenna can be mounted is arranged below the space, and an opening portion is provided in at least a portion of a portion of the conductive body plate that faces the base substrate.

[0006] An aspect of an embodiment of the present disclosure is a conductive body plate in which a communication module having a first antenna and a base substrate, and a second antenna can be respectively mounted, the conductive body plate being arranged between a roof panel and a roof liner of a vehicle, wherein

[0007] An opening portion is provided in at least a portion of a portion that faces the base substrate.

[0008] According to the present disclosure, it is possible to improve the transmission efficiency of a wireless signal. BRIEF DESCRIPTION OF DRAWINGS

[0009] Features, advantages, and technical and industrial significance of exemplary embodiments of the application will be described below with reference to the accompanying drawings, in which like numerals denote like elements, and wherein:

[0010] Figure 1 is a schematic diagram showing one example of the structure of a vehicle system in an embodiment.

[0011] Figure 2 is a schematic diagram showing one example of the structure of the DCM 10 and the in-vehicle device 20.

[0012] Figure 3 is a block diagram schematically showing one example of the functional structure of the DCM 10.

[0013] Figure 4 is a hardware appearance diagram of the DCM 10.

[0014] Figure 5 is a perspective view illustrating a configuration of the DCM 10.

[0015] Figure 6 is a sectional view illustrating a configuration of the DCM 10.

[0016] Figure 7 is a sectional view illustrating a configuration of the DCM 10. DETAILED DESCRIPTION

[0017] Vehicles equipped with communication terminals are increasing. In addition, in recent years, along with an increase in performance of vehicles, there is a tendency for an increase in the amount of communication data, and it is required to maximize the efficiency of communication.

[0018] In a communication module that utilizes a high-frequency band wave having high directivity, in order to secure a ground height, it is common to arrange an antenna to an upper portion (for example, a vicinity of a roof) of a vehicle.

[0019] A roof structure according to an embodiment of the present disclosure forms a space in which a communication module having a first antenna and a substrate board, and a second antenna are arranged, between a roof panel and a roof lining.

[0020] The roof panel refers to a member that constitutes an upper surface of a roof of a vehicle. In addition, the roof lining refers to an interior trim member arranged to a lower surface of the roof of the vehicle.

[0021] The communication module mounted on the vehicle performs input and output of wireless signals via the first antenna. By providing a space between the roof panel and the roof lining, and arranging the communication module and the antenna in the space, a high gain can be obtained.

[0022] The second antenna refers to an antenna for use other than data communication, such as a broadcast receiving antenna, a GPS antenna, and the like.

[0023] In such a roof structure, it is common to cover an upper surface of the space with a non-conductive body (for example, a resin plate), and to cover other surfaces (side surfaces, a bottom surface) with a conductive body (for example, a metal plate). Thereby, the antenna can be protected from electromagnetic noise occurring in the vehicle, and a decrease in gain due to noise can be suppressed.

[0024] However, if the space provided in the roof lining is covered with a conductive body, hollow resonance can occur due to electromagnetic waves occurring inside and outside. In a case where the resonance frequency is close to a frequency at which communication is intended, it can be possible to hinder communication.

[0025] Furthermore, if the substrate board and the conductive body plate of the communication module are close to each other, high-frequency currents of opposite phases can flow between the substrate board and the conductive body plate. The high-frequency currents act like noise, and sometimes the radiation performance of the first antenna can decrease.

[0026] Therefore, in the roof structure disclosed herein, a non-conductive roof panel cover is disposed above the space. Additionally, a conductive plate capable of mounting the communication module and the second antenna is disposed below the space, and at least a portion of the conductive plate facing the substrate has an opening.

[0027] That is, a conductive plate is used to cover the space inside the vehicle roof, and an opening (cut, etc.) is provided in the part of the conductive plate close to the substrate. This serves to shield electromagnetic waves generated inside the vehicle while suppressing the aforementioned reverse-phase current, thereby increasing the radioactivity of the electromagnetic waves. Furthermore, by adjusting the size of the opening, resonance can be suppressed or the resonant frequency can be controlled.

[0028] Furthermore, the conductive plate may also have upright portions surrounding the sides of the space. That is, the conductive plate can also be used to cover the four sides and the bottom surface.

[0029] Alternatively, the first antenna can be a cellular communication antenna, and the second antenna can be a broadcast reception antenna. For example, the second antenna can be a television reception antenna, a radio reception antenna, etc. Broadcasting operates on a lower frequency band than cellular communication and is more susceptible to noise, thus offering the practical advantage of using a conductive plate for shielding.

[0030] The maximum length of the opening (e.g., diagonal length) can be determined based on the frequency of the noise to be suppressed.

[0031] With the size of the opening set as X, according to the working principle of the slot antenna, the upper limit wavelength λ of the radio wave transmitted through the opening is represented by X = λ / 2.

[0032] For example, by setting the maximum length of the opening to 200 mm or less, it is possible to shield radio waves with frequencies below 750 MHz while allowing radio waves with frequencies above 750 MHz to pass through. In other words, it is possible to reduce resonance occurring at frequencies above 750 MHz. The maximum length of the opening can be appropriately set based on the frequency of the noise to be suppressed, as described above, and the spacing of the screw holes used to fix the communication module, etc.

[0033] Hereinafter, specific embodiments of the present disclosure will be described with reference to the accompanying drawings. Unless otherwise specified, the hardware structures, module structures, functional structures, etc., described in each embodiment are not intended to limit the scope of the disclosed technology to these.

[0034] First Implementation Method

[0035] Reference Figure 1This section describes the overview of the vehicle system according to the first embodiment. The vehicle system according to this embodiment is configured to include a vehicle 1.

[0036] Vehicle 1 is a networked vehicle with communication capabilities with external devices. Vehicle 1 is configured to include a DCM (Data Communication Module) 10 and an on-board unit 20.

[0037] External devices refer to devices located outside of vehicle 1. External devices can be, for example, servers connected to the Internet, or terminals or roadside devices located near vehicle 1 that can communicate directly with DCM10 (mounted in other vehicles).

[0038] DCM10 is a device that enables wireless communication with other devices (or external networks) via a network. DCM10 functions as a gateway for connecting components of vehicle 1 (hereinafter referred to as vehicle components) to networks or external devices outside the vehicle.

[0039] DCM10 can provide communication (cellular communication) to a mobile communication network. The mobile communication network is connected to wide area networks such as the Internet, thereby enabling various components of vehicle 1 to communicate with any external device.

[0040] The in-vehicle device 20 is installed in vehicle 1 and provides information to the occupants of vehicle 1. The in-vehicle device 20 is also referred to as a vehicle navigation device, infotainment device, or in-vehicle multimedia head unit. It can provide navigation and entertainment to the occupants of the vehicle. The in-vehicle device 20 may also have the function of receiving television and radio broadcasts. Furthermore, the in-vehicle device 20 may also be a device that can cooperate with smartphones, etc.

[0041] It is believed that the amount of communication data processed by the vehicle's DCM will gradually increase with the improvement of vehicle performance. Therefore, it is necessary to improve the communication efficiency of the DCM.

[0042] Therefore, in this embodiment, the DCM10 houses both the antenna and the communication module inside the roof of the vehicle 1. This ensures a good field of vision while minimizing the length of the cable connecting the antenna and the communication module. Specific configuration methods will be described later.

[0043] Furthermore, in this embodiment, an antenna for broadcast reception used by the vehicle-mounted device 20 is disposed inside the roof of the vehicle 1. That is, both a cellular communication antenna (first antenna) and a broadcast reception antenna (second antenna) are disposed inside the roof of the vehicle 1.

[0044] To improve noise immunity, a conductive material is used to shield the interior of the vehicle roof. This improves the reception sensitivity of television and radio broadcasts.

[0045] On the other hand, if the interior of the vehicle roof is shielded using a conductor, void resonance may occur within the roof, hindering communication. Furthermore, if the DCM10 substrate and the conductor are positioned close to each other, high-frequency currents in reverse phase will flow, generating noise and potentially reducing the antenna's performance. Therefore, in this embodiment, this problem is addressed by shaping the conductor disposed inside the vehicle roof. Details will be described later.

[0046] Figure 2 This diagram illustrates the constituent elements of the DCM 10 and the vehicle-mounted device 20 according to this embodiment. The DCM 10 according to this embodiment is configured to include a control device 11, a storage device 12, a cellular antenna 13, a cellular communication module 14, and an auxiliary battery 15.

[0047] The vehicle-mounted device 20 is configured to include a control device 21, a storage device 22, a broadcast receiving antenna 24, and a broadcast receiving module 25.

[0048] First, let's explain DCM10.

[0049] The control device 11 is a computing unit that implements various functions of the DCM 10 by executing a predetermined program.

[0050] The control device 11 performs the function of relaying communication between external devices and components (vehicle components) of the vehicle 1. A vehicle component refers to, for example, one or more on-board devices mounted on the vehicle 1. An external device refers to, for example, a server device that provides information.

[0051] For example, when a vehicle component needs to communicate with an external device, the control device 11 performs the function of relaying data sent from the vehicle component to the external device (or external network). Additionally, it performs the function of receiving data sent from the external device (or external network) and transmitting that data to the appropriate vehicle component.

[0052] Furthermore, the control device 11 can perform the inherent functions of the device. For example, the control device 11 is configured to perform the monitoring function and communication function of the safety system, and to issue safety notifications and emergency notifications based on triggers occurring inside the vehicle.

[0053] Storage device 12 is a memory device that includes a main storage device and an auxiliary storage device. The auxiliary storage device stores the operating system (OS), various programs, various tables, etc. Furthermore, by loading the programs stored therein into the main storage device and executing them, various functions that meet predetermined purposes can be achieved, as described later.

[0054] The cellular antenna 13 is an antenna element that inputs and outputs wireless signals. In this embodiment, the cellular antenna 13 is suitable for cellular communication (e.g., mobile communication such as 3G, LTE, and 5G). Furthermore, the cellular antenna 13 can also be configured to include multiple physical antennas. For example, in the case of mobile communication via high frequency, multiple antennas can be distributed to stabilize the communication.

[0055] Cellular communication module 14 is a communication module used for mobile communication.

[0056] The auxiliary battery 15 is used to supply backup power to the DCM 10. The DCM 10 operates using power supplied from the vehicle 1, but the power supply is sometimes interrupted due to traffic accidents, illegal activities, etc. In such cases, the auxiliary battery 15 supplies power to the DCM 10. Therefore, the DCM 10 can continue to operate even in emergencies. Furthermore, the auxiliary battery 15 can also be charged while receiving power from the vehicle 1.

[0057] Next, the functions performed by the control device 11 will be explained. Figure 3 This diagram illustrates the functional modules of the control device 11. The functional modules shown in the diagram can be implemented by the control device 11 executing a program stored in a storage unit such as ROM.

[0058] The data relay unit 111 relays the transmission and reception of data between vehicle components. For example, it performs the following processing: receiving a message sent by a first device connected to the vehicle network, and forwarding the message to a second device connected to the vehicle network as needed.

[0059] Furthermore, when the data relay unit 111 receives a message from the vehicle component indicating that an external device is the destination, it relays the message to the external network. Additionally, it receives data sent from the external network and forwards the data to the appropriate vehicle component.

[0060] In the event of an abnormal situation occurring inside vehicle 1, the emergency notification unit 112 issues an emergency notification to the operator outside the vehicle. Examples of abnormal situations include traffic accidents and vehicle malfunctions. For instance, upon a predetermined trigger such as the pressing of a call button located inside the vehicle or the deployment of airbags, the emergency notification unit 112 initiates a connection with the operator, enabling communication between the vehicle occupants and the operator. Furthermore, during an emergency notification, the emergency notification unit 112 can also send the vehicle's location information to the operator. In this case, the emergency notification unit 112 can also obtain location information from the GPS module 26.

[0061] The safety management unit 113 performs safety monitoring. For example, based on data received from the ECU of the electronic lock controlling the vehicle, the safety management unit 113 detects that the vehicle has been unlocked without proper procedures and sends a safety notification to a predetermined device. Furthermore, the safety notification may include the vehicle's location information. In this case, the safety management unit 113 may also obtain location information from the GPS module 26. The safety management unit 113 may also periodically send the obtained location information to a pre-designated external device if it determines that a safety issue has arisen with the vehicle.

[0062] Next, the vehicle-mounted device 20 will be explained.

[0063] The on-board device 20 is a device that provides information to the occupants of the vehicle.

[0064] The control device 21 is a computing unit that executes a predetermined program to realize various functions of the vehicle-mounted device 20.

[0065] The control device 21 is configured, for example, to provide the following functions.

[0066] Navigation function: The function of searching for the vehicle's driving route and guiding passengers.

[0067] Terminal link function: Connects to the terminals (smartphones, etc.) of vehicle occupants to play music and animations, mirror images, etc.

[0068] Audio function: The function of playing music saved on the storage device.

[0069] Television / Radio Function: Function to receive radio broadcasts and digital television broadcasts.

[0070] These functions can be provided, for example, via the input / output unit 23 (e.g., a touch panel display) described later.

[0071] Storage device 22 is a memory device that includes a main storage device and an auxiliary storage device. The auxiliary storage device stores the operating system (OS), various programs, various tables, etc. By loading the programs stored therein into the main storage device and executing them, various functions that meet the predetermined purpose can be achieved, as described later.

[0072] The input / output unit 23 is a unit that accepts input operations from the user and provides prompts to the user. Specifically, the input / output unit 23 consists of a touch panel and its control unit, and a liquid crystal display and its control unit. In this embodiment, the touch panel and the liquid crystal display are configured as a single touch panel display. The input / output unit 23 may also include a unit for outputting sound (amplifier, speaker) and a unit for inputting sound (microphone), etc.

[0073] The broadcast receiving antenna 24 is an antenna element for receiving radio waves from television broadcasts and radio broadcasts. Furthermore, the broadcast receiving antenna 24 can also be configured to include multiple physical antennas. For example, multiple antennas pointing in different directions can be used as the broadcast receiving antenna 24.

[0074] Furthermore, the broadcast receiving antenna 24 can be either built into the vehicle-mounted device 20 or located outside the vehicle-mounted device 20. In this case, the broadcast receiving antenna 24 can also be connected to the vehicle-mounted device 20 via a cable or the like.

[0075] The broadcast receiver module 25 is used to receive television broadcasts and radio broadcasts.

[0076] Like DCM10, vehicle-mounted device 20 can be configured as a computer having a processor such as CPU or GPU, a main storage device such as RAM or ROM, an auxiliary storage device such as EPROM or disk drive, and a removable medium.

[0077] In addition, the DCM10 and the vehicle-mounted device 20 have interface units for connecting to the vehicle network.

[0078] Furthermore, in this embodiment, multiple vehicle components, including DCM10 and vehicle-mounted device 20, are interconnected via network bus 30. CAN (Controller Area Network) can be cited as an example of a vehicle-mounted network standard. Additionally, when multiple standards are used in the vehicle-mounted network, the communication interface may have multiple interface devices that match the standard of the communication destination. Ethernet (registered trademark) can be cited as an example of a communication standard other than CAN.

[0079] Network bus 30 is the communication bus that constitutes the in-vehicle network. Furthermore, while one bus is illustrated in this example, vehicle 1 may also have two or more communication buses. Multiple communication buses can also be interconnected using DCM 10 or a gateway that aggregates multiple communication buses.

[0080] Figure 4 This is a diagram showing the appearance of the DCM10 hardware.

[0081] The hardware configuration of DCM10 includes a main board (base board) and various components mounted on the main board.

[0082] The main substrate is a substrate on which the control device 11, storage device 12, cellular antenna 13, cellular communication module 14, and auxiliary battery 15 are mounted. In addition, in this example, the cellular antenna 13 is mounted on the main substrate, but the cellular antenna 13 can also be connected to the main substrate via an external port.

[0083] Furthermore, the DCM10 may also include multiple connectors for external connections. One of these connectors may be a connector corresponding to an in-vehicle network bus such as CAN or Ethernet. The other connector may be an expansion connector. Examples of such connectors include a port for connecting an external antenna to the DCM10, and a USB port for connecting external devices (such as maintenance terminals) to the DCM10.

[0084] The hardware shown in the diagram is located inside the roof of vehicle 1. Figure 5 This means to explain Figure 4 The diagram shows the DCM10 embedded in vehicle 1.

[0085] As shown in the figure, an opening is provided in the roof panel 2 of vehicle 1. At the bottom of the opening, a roof liner 3 (interior trim) is provided.

[0086] The DCM10 is first mounted to the mounting plate 5. In this embodiment, the mounting plate 5 is a metal plate (conductive). The mounting plate 5 has a connecting portion (e.g., screw holes) for connecting to the main substrate of the DCM10, and the DCM10 is connected to the main substrate by means of this connecting portion. In addition, the mounting plate 5 is provided with an opening of a predetermined size so that the DCM10 is mounted across the opening (described later).

[0087] Alternatively, components other than DCM10 can be mounted on mounting plate 5. For example, vehicle-mounted device 20, broadcast receiving antenna 24 connected to vehicle-mounted device 20, etc., can also be connected to mounting plate 5. In the illustrated example, broadcast receiving antenna 24 is connected to mounting plate 5 together with DCM10.

[0088] A mounting plate 5, on which the DCM 10 and the broadcast receiving antenna 24 are installed, is inserted through an opening in the roof panel 2 and fixed to the space between the roof panel 2 and the roof lining 3 (hereinafter referred to as the storage space). The mounting plate 5 can also be fixed to the roof panel 2 via conductive components such as screws. This allows the mounting plate 5 to be grounded.

[0089] Finally, the opening of the roof panel is sealed with the roof panel cover 4. The roof panel cover 4 is formed from a non-conductive raw material (such as resin).

[0090] Next, refer to Figure 6 This describes the detailed shape of the fixing plate 5. Figure 6 This is a cross-sectional view (VI-VI section) showing the fixed plate 5 installed on the vehicle 1.

[0091] like Figure 5 As shown, the mounting plate 5 has an opening for mounting the DCM10 across the opening. When the DCM10 is connected to the mounting plate 5 using multiple screws, the length of one side of the opening is designed to be shorter than the spacing between the screws.

[0092] The fixing plate 5 consists of a surface that contacts the roof liner 3, i.e., the surface located at the bottom of the storage space, and four vertically erected surfaces ("erected portions" in this disclosure). Figure 6 It is composed of (dashed line diagram). The storage space is surrounded by vertical sections.

[0093] Previously, it was known to house the DCM 10 and the broadcast receiving antenna 24 within a storage space surrounded by the roof panel and roof lining. In this configuration, the cross-sectional view is as follows: Figure 7 As shown.

[0094] However, in this case, five of the six sides forming the storage space are surrounded by conductors, so void resonance can sometimes occur due to electromagnetic waves generated inside and outside the storage space. The resonant frequency may vary depending on the storage space, the size of the mounting plate, etc., but when the resonant frequency is close to the frequency used by the DCM10 in communication, it may hinder the communication. Furthermore, since the base plate and the mounting plate (i.e., the conductors) of the communication module are close together, a high-frequency current in opposite phase will occur between the base plate and the mounting plate, which becomes noise and may also hinder communication.

[0095] On the other hand, in this embodiment, such as Figure 6 As shown, an opening is provided in the fixing plate 5, and the DCM10 is arranged across this opening. According to this structure, the substrate and the fixing plate can be separated, thus suppressing the occurrence of reverse-phase current. That is, antenna performance can be improved. Furthermore, by adjusting the size of the opening, the frequency of the transmitted electromagnetic waves can be controlled, thus suppressing resonance occurring in the storage space.

[0096] For example, it is known that when the long side of the storage space is less than 2 meters, the resonant frequency falls within the UHF band (around 1 GHz). This band can affect cellular communications and GNSS signals. Furthermore, if high-order resonances occur in the SHF band (e.g., several GHz), they may affect communications such as Wi-Fi. Therefore, to suppress these resonances and ensure that electromagnetic waves in this band are transmitted from the inside of the storage space to the outside, the size of the opening can be adjusted.

[0097] When the maximum length of the opening (e.g., the length of the diagonal) is set to X, according to the working principle of the slot antenna, the upper limit wavelength λ of the electromagnetic wave transmitted through the opening is represented by X = λ / 2. Here, for example, when the frequency of the noise (resonant frequency) is 1150MHz, its wavelength is 260mm. Therefore, if the maximum length of the opening is set to 130mm or more, electromagnetic waves of that frequency can be transmitted, and resonance can be reduced.

[0098] Variations

[0099] The above-described embodiments are merely examples, and the present invention can be implemented with appropriate modifications without departing from its spirit.

[0100] For example, in one embodiment, an antenna for cellular communication (first antenna) and an antenna for broadcast reception (second antenna) are arranged in the storage space, but the second antenna is not limited to the antenna for broadcast reception.

[0101] Furthermore, the storage space can also be used to configure antennas for receiving positioning signals transmitted from positioning satellites (also known as GNSS satellites). This antenna is also an example of a second antenna. By providing openings in the mounting plate, resonance can be reduced, thus improving the reception performance of these antennas.

[0102] Furthermore, vehicle 1 can also be equipped with a terminal (V2X terminal) that communicates with other vehicles and roadside devices located near vehicle 1. The V2X terminal uses centimeter wave radio waves and millimeter wave radio waves for communication.

[0103] Functions provided by V2X terminals include, for example, exchanging data with other vehicles via vehicle-to-vehicle communication to prevent collisions, and obtaining traffic signal-related data via road-to-road communication. Furthermore, V2X functionality can also be included as part of autonomous driving capabilities.

[0104] The V2X terminal performs functions such as generating prescribed messages and periodically broadcasting them outside the vehicle, and obtaining messages sent by other V2X terminals and controlling the vehicle's movement based on those messages.

[0105] In this case, an antenna for V2X communication can also be configured in the storage space.

[0106] Furthermore, for example, the description of the implementation shows a communication module and antenna utilizing cellular communication, but the DCM10 may also be equipped with multiple sets of communication modules and antennas corresponding to other communication standards. Examples of such communication methods include Wi-Fi (registered trademark) and Bluetooth (registered trademark).

Claims

1. A roof structure of a vehicle, in which a space in which a communication module having a first antenna and a substrate board and a second antenna are arranged is formed between a roof panel and a roof liner, wherein a roof panel cover of a non-conductive body is arranged above the space, a conductive plate in which the communication module and the second antenna can be installed is arranged below the space, and an opening portion is provided in at least a portion of a portion of the conductive plate that faces the substrate board.

2. The roof structure of a vehicle according to claim 1, wherein the conductive plate has a standing portion that surrounds a lateral side of the space.

3. The roof structure of a vehicle according to claim 1, wherein the first antenna is an antenna for cellular communication.

4. The roof structure of a vehicle according to claim 1, wherein the second antenna is an antenna for broadcast reception.

5. A conductive plate in which a communication module having a first antenna and a substrate board and a second antenna can be installed, the conductive plate being arranged between a roof panel and a roof liner of a vehicle, wherein an opening portion is provided in at least a portion of a portion of the conductive plate that faces the substrate board. ​ ​ ​ ​ ​ ​ ​

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