JP4356427B2 - Vehicle antenna device - Google Patents

Description

  The present invention relates to an antenna device mounted on a moving body such as a vehicle, in particular, without being affected by variations in relative permittivity, without obstructing the field of view, and further, the restriction on the operating frequency is relaxed, The present invention relates to a vehicular antenna device that can change directivity according to the traveling angle and position of a vehicle and can further improve transmission and reception performance.

  With the recent development of information communication, various information communication devices such as TVs, car navigation systems, ETCs, etc. are being installed in vehicles in addition to conventional AM / FM radio. In addition, by connecting to the Internet from a vehicle, it has become possible to receive various services such as obtaining various information, distributing music data, e-mail, and electronic payment. In order to use such information communication equipment or services, it is necessary to send and receive radio waves to and from external base stations and the like to exchange information, which requires an antenna.

  Conventionally, a vehicular antenna device has often used an external rod antenna, but there are problems such as lack of aesthetics due to the formation of new protrusions on the exterior of the vehicle, and wind noise during driving, etc. In recent years, its use has been decreasing. Instead of the rod antenna, the vehicle is formed on an antenna (for example, see Patent Document 1), a rearview mirror (room mirror) (for example, see Patent Document 2), a side mirror (door mirror), or the like attached to a rear glass. An antenna device has been proposed (see, for example, Patent Document 3).

  In the antenna described in Patent Document 1, a black frame printed layer is formed on the periphery of a front window glass of a vehicle, and an antenna pattern is disposed on the black frame. According to this antenna, since it does not have to be arranged on the dashboard in front of the room, it is not obstructed and the front view is not obstructed.

  The antenna described in Patent Document 2 uses a room mirror support stay attached to the front side of the ceiling in the passenger compartment as an antenna. According to this antenna, since the components currently mounted on the vehicle are used as the antenna, the aesthetic appearance of the vehicle is not impaired.

In the antenna described in Patent Document 3, a housing of a door mirror is formed of a material that transmits a radio signal, and a VICS radio beacon receiving antenna is provided in the housing. According to this antenna, since the antenna is provided in the housing of the door mirror, the aesthetics of the vehicle is not impaired.
JP 2001-53524 A (FIG. 1) Japanese Patent Laid-Open No. 10-287180 (0005, 0006, FIG. 2) Japanese Patent Laid-Open No. 2001-16016 (FIG. 1)

  However, although the antenna described in Patent Document 1 uses the front window glass of the vehicle, it is easily affected by variations in the relative permittivity of the front window glass, and many antenna patterns are arranged. As a result, there is a problem that the field of view becomes worse and the directivity cannot be adjusted according to the traveling angle and position of the vehicle.

  Further, since the antennas described in Patent Document 2 and Patent Document 3 are arranged in the rearview mirror support stay and the door mirror housing, the size of the antenna is considerably reduced and the operating frequency is limited. Since directivity cannot be adjusted according to the position, there is a high possibility that reception performance will be significantly degraded.

  Therefore, the object of the present invention is not affected by variations in relative permittivity, does not obstruct the field of view, and further limits the frequency of use, and directivity according to the traveling angle and position of the vehicle. It is possible to provide a vehicle antenna device that can change the transmission / reception performance and can further improve transmission / reception performance.

The present invention, in order to achieve the above object, times on the ceiling side and the support shaft rotatably mounted in the passenger compartment, a first rotating shaft formed on the support shaft, by the first rotation axis a sun visor body which can be rotated to the light blocking position of the dynamic position, a vehicular antenna apparatus that includes a radiation element formed on the sun visor body, the sun visor body, the Ri Do from the radio wave transmitting member comprises a first light shielding portion which radiating element is formed and a second light shielding portion which is attached via a second pivot shaft to the first light shielding portion Do Ri from the radio wave reflecting member, to provide a vehicle antenna device angle, wherein Rukoto be adjusted between the second of the second light shielding portion and the first light shielding portion by the rotation shaft.

The second light shielding unit preferably operates as a ground with respect to the radiating element .

  It is preferable that the support shaft includes a hollow portion having a hollow inside, and the radiating element is fed by a power feeding member introduced into the sun visor body through the hollow portion.

  The support shaft or the rotation shaft preferably includes a power feeding member connected to the radiating element at a high frequency.

  The sun visor body preferably includes a circuit board constituting at least one type of electronic circuit among a transceiver circuit and an antenna matching circuit connected to the radiating element.

  The radiating element is provided in each of a plurality of sun visor main bodies, each of the radiating elements includes a receiving unit, and receives radio waves while switching the antenna so that the receiving state at the receiving unit is the best receiving state. It is preferable to include a reception control unit.

  According to the vehicle antenna device of the present invention, the sun visor body can be changed to either the windshield side or the side window glass side by the support shaft, and the attitude of the sun visor can be changed by the rotation shaft. The directivity of the antenna device can be changed according to the reception sensitivity without being affected by the relative dielectric constant.

  According to the vehicle antenna device of the present invention, since the power feeding member is passed through the hollow portion formed in the support shaft, the power feeding member does not come out of the sun visor body, so that the use of the sun visor is not obstructed, and the aesthetics of the vehicle interior Is not impaired.

  According to the vehicle antenna device of the present invention, since the support shaft or the rotation shaft is provided with the power feeding member that is connected to the radiating element in high frequency, the wiring connected to the radiating element can be gathered, and the aesthetic appearance is improved. There is no loss.

  According to the vehicle antenna device of the present invention, since the second light shielding portion made of the radio wave reflecting material is provided, strong directivity can be obtained, and as a result, the gain of the antenna device can be increased.

  According to the vehicle antenna device of the present invention, since the second light shielding unit operates as a ground, the gain of the antenna device can be increased.

  According to the vehicle antenna device of the present invention, the sun visor body includes a circuit board that constitutes at least one type of electronic circuit among a transceiver circuit and an antenna matching circuit connected to the radiating element. Since it is possible to supply the sun visor main body to the vehicle manufacturer after the circuit board constituting the electronic circuit such as the receiver is incorporated in the sun visor main body by the parts manufacturer, it is possible to reduce the number of mounting steps on the vehicle assembly line. .

  According to the vehicle antenna device of the present invention, the radiating element is provided in each of a plurality of sun visor main bodies, and each of the radiating elements includes a receiving unit, and the receiving state at the receiving unit is the best receiving state. Since the reception control unit that receives the radio wave while switching the antenna is provided, the radio wave can always be received in the best reception state, so that high performance of the antenna can be ensured and the gain can be increased.

  According to the vehicle antenna device of the present invention, since it is installed in the vehicle interior, a structure such as waterproofing can be omitted.

  FIG. 1 shows the inside of a vehicle to which a sun visor to which a vehicle antenna device according to a first embodiment of the present invention is applied is attached. The driver's side sun visor 5A and the passenger's side sun visor 5B are formed symmetrically. The sun visor main body 5a and the support shaft 4a for rotatably supporting the sun visor main body 5a with respect to the passenger compartment ceiling 2 are illustrated. And a support bar having a rotating shaft that does not. The sun visors 5A and 5B are attached by a support shaft 4a near the windshield 3 of the passenger compartment ceiling 2 and can be rotated to positions on the windshield 3 side and the side window glass 7 side. The position rotated to the second side and the light shielding position can be rotated by a rotation shaft (not shown). The sun visor body 5a incorporates antenna devices 1A and 1B each including a radiating element and a feed line.

  When not in use, the sun visors 5A and 5B are rotated to the vehicle interior ceiling 2 side by a rotation shaft (not shown), and are rotated to the windshield 3 side when in use. Make sure you can check. At this time, the sun visor body 5a shields sunlight. When the sun visor body 5a can be recognized from the outside through the windshield 3, the antenna devices 1A and 1B incorporated in the sun visor body 5a are less affected by the ceiling 2 of the passenger compartment, and can communicate with the outside. Become. Further, the sun visor body 5 a can be rotated to the side window glass 7 side by the support shaft 4 a, and communication is possible via the side window glass 7.

  FIG. 2 shows a sun visor to which the vehicle antenna device according to the first embodiment is applied. As shown in FIG. 2A, the sun visor 5A includes a sun visor body 5a including the antenna device 1A inside, and a support bar 4. The support bar 4 includes a support shaft 4a that rotatably supports the sun visor body 5a between the windshield 3 side and the side window glass 7 side with respect to the cabin ceiling 2, and the sun visor body 5a on the cabin ceiling 2 side. And a rotation shaft 4b for rotating the light shielding position. The support shaft 4a has a hollow portion 4f, and feeds power to the antenna through a coaxial cable described later in the hollow portion 4f. The sun visor body 5a is made of a material that hardly absorbs or reflects radio waves.

  As illustrated in FIG. 2B, the antenna device 1 </ b> A includes, for example, a radiating element 11 and a coaxial cable 12 as a power feeding member that feeds power to the radiating element 11. An inner conductor 12a of the coaxial cable 12 is connected to the feeding point 11a of the radiating element 11, and an outer conductor 12b that is a braided wire of the coaxial cable is connected to the other feeding point 11b. In the coaxial cable 12, an insulator 12c is interposed between the inner conductor 12a and the outer conductor 12b, and the outer side of the outer conductor 12b is covered with a coating 12d. The coaxial cable 12 is drawn inside the sun visor main body 5a and then drawn into the vehicle interior ceiling 2 through the hollow portion 4f of the support shaft 4a, and is pulled to a place where the communication device accommodated in a predetermined position is mounted. Turned and connected to communication equipment. The radiating element 11 is fixed by an appropriate means at an appropriate location in the sun visor body 5. Similarly, the coaxial cable 12 routed around each part is similarly fixed at appropriate places by appropriate means. Since the antenna device 1B is the same as the antenna device 1A, the description thereof is omitted.

  When using the antenna device 1A, first, the communication device to which the antenna device 1A is connected is turned on. Next, the sun visor body 5a is rotated so as to be positioned on the windshield 3 side while observing the meter indicating the signal intensity of the communication device, and the position of the sun visor is determined. Next, the posture is determined by adjusting the rotation angle so that the meter showing the signal intensity is rotated from the position on the passenger compartment ceiling 2 side to the light shielding position and has the highest strength. If the signal strength indicated by the meter is weak, the sun visor body 5a is rotated so as to be positioned on the side window glass 7 side to change the position of the sun visor 5A, and then is rotated from the position on the passenger compartment ceiling 2 side to the light shielding position. Then, the rotation angle of the sun visor 5A is determined to determine the attitude of the sun visor 5A.

  FIGS. 3A to 3D show the directivity in the horizontal direction of the vehicle antenna device according to the first embodiment. When the antenna device 1A incorporated in the driver's side sun visor and the antenna device 1B incorporated in the passenger's side sun visor are respectively positioned on the windshield 3 side, as shown in FIG. In the direction, the antenna devices 1A and 1B have the combined directivity. As described above, the antenna devices 1A and 1B have directivity in a direction orthogonal to the light shielding portion of the sun visor body 5a, and therefore are positioned on the windshield 3 side or the side window glass 7 side as necessary. That is, as shown in FIGS. 3B to 3D, various directivities can be obtained depending on where the antenna devices 1A and 1B are located.

  According to the vehicle antenna devices 1A and 1B of the first embodiment, the antenna directivity can be changed by rotating the antenna devices 1A and 1B on the driver's seat side or on the passenger seat side. Even can be received.

  FIG. 4 shows a sun visor to which the vehicle antenna device according to the second embodiment of the present invention is applied. The sun visor 5A is attached to the driver's seat side, and includes a sun visor body 5a having an antenna device 1C therein and a support bar 4. The support bar 4 includes a support shaft 4a that rotatably supports the sun visor body 5a between the windshield 3 side and the side window glass 7 side with respect to the cabin ceiling 2, and the sun visor body 5a on the cabin ceiling 2 side. And a first rotation shaft 4c that rotates the light shielding position. The sun visor body 5a includes a ground plate 8 rotatably attached to the lower side of the sun visor body 5a via a second rotation shaft 4d. The ground plate 8 is a flat plate made of a conductive material such as metal or carbon, and serves as a ground for the radiating element. This antenna device 1C is the same as the antenna device 1A shown in FIG.

  When this antenna device 1C is used, the arrangement and posture of the sun visor are determined in the same manner as in the first embodiment. First, the communication device to which the antenna device 1C is connected is turned on. Next, while looking at the meter indicating the signal strength of the communication device, the sun visor main body 5a is rotated so as to be positioned on the windshield 3 side, and is rotated from the position on the ceiling 2 side to the light shielding position. Adjust the rotation angle so that the meter showing the maximum strength. Furthermore, the ground plate 8 is rotated with respect to the sun visor body 5a by the second rotation shaft 4d to adjust the rotation angle so that the meter has the maximum strength. If the signal strength indicated by the meter is weak, the sun visor body 5a is rotated so as to be positioned on the side window glass 7 side to change the position of the sun visor 5A, and then is rotated from the position on the passenger compartment ceiling 2 side to the light shielding position. Then, the rotational position of the sun visor 5A is determined to determine the attitude of the sun visor 5A. Thus, the ground plate 8 adjusts the radio wave transmission direction of the antenna by adjusting the angle formed with the sun visor body 5a. That is, the directivity of the antenna device 1 </ b> C is direct to the light shielding portion of the sun visor body 5 a and has directivity only in the front side direction of the ground plate 8.

  FIGS. 5A to 5H show the directivity in the horizontal direction and the vertical direction of the vehicle antenna device according to the second embodiment. Here, the antenna device 1C is provided on the sun visor 5A on the driver seat side, and the antenna device 1D is provided on the sun visor 5A on the passenger seat side. Since this antenna device 1D is the same as the antenna device 1A shown in FIG.

  When the antenna devices 1C and 1D are used in combination, the position and orientation of the sun visor are determined. First, the communication device to which the antenna devices 1C and 1D are connected is turned on. Next, while looking at the meter indicating the signal strength of the communication device, the sun visor body 5a incorporating the antenna devices 1C and 1D is rotated so as to be positioned on the windshield 3 side, and light is transmitted from the position on the vehicle ceiling 2 side. The rotation angle is adjusted so that the meter indicating the signal intensity by rotating to the shielding position has the maximum strength. Furthermore, the ground plate 8 is rotated with respect to the sun visor body 5a by the second rotation shaft 4d to adjust the rotation angle so that the meter has the maximum strength. If the signal strength indicated by the meter is weak, the sun visor body 5a is rotated so as to be positioned on the side window glass 7 side to change the position of the sun visor 5A, and then is rotated from the position on the passenger compartment ceiling 2 side to the light shielding position. Then, the rotation angle of the sun visor 5A is determined to determine the attitude of the sun visor 5A. When the antenna device 1C on the driver's seat side is turned to the windshield 3 side and the antenna device 1D on the passenger seat side is turned to the side window glass 7 side, the directivity in the horizontal direction as shown in FIG. And has directivity in the vertical direction as shown in FIG. As described above, the antenna devices 1C and 1D have directivity in a direction orthogonal to the light shielding portion of the sun visor body 5a, and therefore are positioned on the windshield 3 side or the side window glass 7 side as necessary. That is, as shown in FIGS. 5B to 5H, various directivities can be obtained depending on where the antenna devices 1C and 1D are positioned.

  According to the vehicular antenna devices 1C and 1D according to the second embodiment of the present invention, the provision of the ground plate 8 can adjust the radio wave transmission direction of the antenna, and therefore the front of the antenna devices 1C and 1D. Since it has directivity on the side, even a weak radio wave can be received without being disturbed by other radio waves. Further, since the antenna directivity can be changed by rotating the antenna devices 1C and 1D, the antenna device 1C and 1D can be received in a better state, so even a weak radio wave can be received.

  FIG. 6 shows a sun visor to which the vehicular antenna apparatus according to the third embodiment of the present invention is applied. This sun visor 5A is attached to the driver's seat side, and is substantially the same as the sun visor 5A of the second embodiment. The difference is that the sun visor 5A rotates in the horizontal direction with the sun visor body 5a having the antenna device 1E inside. This is a point that includes a ground plate 8 that is movably attached and serves as a ground for the radiating element 11. Since the ground plate 8 is the same as that of the second embodiment, description thereof is omitted.

  According to the vehicular antenna apparatus 1E of the third embodiment of the present invention, since the radio wave transmission direction of the antenna can be adjusted by providing the ground plate 8, directivity is provided on the front side of the antenna apparatus 1E. Therefore, even a weak radio wave can be received without being disturbed by other radio waves. In addition, by rotating the antenna device 1E, the directivity of the antenna can be changed, so that the antenna device 1E can be received in a better state. Therefore, even a weak radio wave can be received.

  Although the antenna device is manually adjusted to increase the signal strength, the position and posture of the sun visor may be changed so that the signal strength is increased by an automatic operation. In addition, signals obtained by the antenna devices on the driver's seat side and the passenger seat side may be used in combination, or may be used individually. Moreover, although it demonstrated as what incorporates an antenna apparatus in a sun visor main body, you may form in the surface of a sun visor main body. In addition to the rod-shaped dipole antenna, a planar slot antenna, a linear microstrip antenna, or the like may be used as the antenna. Moreover, you may form antennas, such as a dipole antenna and a microstrip antenna helical antenna, in a support rod, for example.

  In addition, since this antenna device is provided on both the driver's seat side and the passenger seat side, the signal received by each antenna device may be selected as a received signal, and the diversity antenna may be selected. May be used. According to this, transmission and reception of signals in all directions can be covered.

  In addition, a circuit board constituting at least one of a transmitter / receiver, an amplifier, and an antenna matching circuit may be housed in the sun visor body. According to this, it becomes possible to supply the sun visor main body to the vehicle manufacturer after the circuit board constituting the electronic circuit such as the receiver is incorporated in the sun visor main body by the parts manufacturer in advance. Man-hours can be reduced.

  Further, the transceiver can be housed in the sun visor body. This eliminates the need to route a high-frequency signal line from the antenna to the transceiver, so that signal attenuation can be minimized. Further, the vehicle antenna device is used for all radio wave transmission devices related to vehicles such as digital broadcasting and in-vehicle LAN.

  Further, the rotating shaft may ground the ground plate to the circuit board using a conductive material. Further, although the description has been made assuming that a coaxial cable is used as a power supply line for supplying power to the antenna, since the power supply line varies depending on the type of antenna, it is desirable to use a power supply line according to the type of antenna to be used.

1 is a diagram showing the inside of a vehicle to which a vehicle antenna device according to a first embodiment of the present invention is applied. It is a figure which shows the sun visor which applied the vehicle antenna apparatus which concerns on the 1st Embodiment of this invention. (A) is a figure which shows a sun visor, (b) is a figure which shows the antenna apparatus incorporated in a sun visor main body. It is a figure which shows the directivity of the horizontal direction of the vehicle antenna apparatus which concerns on the 1st Embodiment of this invention. (A)-(d) is a figure which shows the change of the directivity by the position of an antenna apparatus. It is a figure which shows the sun visor which applied the vehicle antenna apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the directivity of the horizontal direction and the vertical direction of the vehicle antenna apparatus which concerns on the 2nd Embodiment of this invention. (A)-(h) is a figure which shows the change of the directivity by the position of the vehicle antenna apparatus. It is a figure which shows the sun visor to which the vehicle antenna apparatus which concerns on the 3rd Embodiment of this invention is applied.

Explanation of symbols

1, 1A, 1B, 1C, 1D, 1E Antenna device 2 Cabin ceiling 3 Windshield 4a Support shaft 4b, 4c, 4d Rotating shaft 4f Hollow portion 5A, 5B Sun visor 5a Sun visor body 7 Side window glass 8 Ground plate 11 Radiation Element 11a, 11b Feed point 12 Coaxial cable 12a Inner conductor 12b Outer conductor 12c Insulator 12d Cover 30, 30A, 30B Directivity curve 40 Vehicle

Claims (6)

A support shaft rotatably mounted in the passenger compartment;
A first rotation shaft formed on the support shaft;
A sun visor body capable of rotating from a position rotated to the ceiling side by the first rotation axis to a light shielding position;
A vehicle antenna device comprising a radiating element formed on the sun visor body,
Mounting the sun visor body, through a first light-shielding portion in which the radiating element Ri Do from the radio wave transmitting member is formed, the second rotational shaft to the first light shielding portion Do Ri from the radio wave reflecting member A second light shielding portion provided ,
The second vehicle antenna apparatus angles, wherein Rukoto be adjusted between the second light shielding portion and the first light shielding portion by the rotation shaft.   The vehicle antenna device according to claim 1, wherein the second light shielding unit operates as a ground with respect to the radiating element.   The said support shaft is provided with the hollow part formed in the inside hollowly, The said radiation | emission element is electrically fed by the electric power feeding member introduce | transduced in the said sun visor main body through the said hollow part. The vehicle antenna device described in 1. The vehicle antenna device according to claim 1, wherein the support shaft or the first rotation shaft includes a power feeding member connected to the radiating element at a high frequency.   3. The vehicle antenna according to claim 1, wherein the sun visor body includes a circuit board constituting at least one type of electronic circuit among a transceiver circuit and an antenna matching circuit connected to the radiating element. 4. apparatus.   The radiating element is provided in each of a plurality of sun visor main bodies, each of the radiating elements includes a receiving unit, and receives radio waves while switching the antenna so that the receiving state at the receiving unit is the best receiving state. The vehicle antenna device according to claim 1, further comprising a reception control unit that performs the operation.

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