JP2007150823A - Vehicle-mounted radio receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise by forming easily a vehicle-mounted radio receiver even if the receive frequency varies and by adding a shield function. <P>SOLUTION: A vehicle-mounted radio receiver 10 for receiving a signal by radio from an external device has a receive module 20 on a main printed board 11. The receive module 20 includes: a receive module board 21; a side wall 22a projecting from at least one side edge of the receive module board 21; and a plate antenna 22 having an upper wall 22b as function of shield plate for covering the upper part of the receive module board 21. A power feeding pattern 24 connected to the side wall 22a of the plate antenna 22 and a radio receive circuit IC26 are provided on the receive module board 21. The receive module 20 is mounted on the main printed board 11. The lower edge of the side wall 22a of the plate antenna 22 is connected to a ground pattern 14 of the main printed board 11, and the radio receiver circuit IC26 is connected to a radio receive pattern 15 of the main printed board 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an in-vehicle wireless receiver and is preferably used for wireless communication of a remote keyless entry system or a tire pressure monitoring system.

Recently, there has been provided a remote keyless entry system for locking and unlocking a car door without inserting a key into the keyhole and operating the system. This system receives a radio signal from a portable device owned by a user. It is received by an antenna of a radio device on the automobile side, and doors are locked / unlocked remotely.
Further, a large number of wireless devices such as a wireless device in a tire air pressure monitoring system that includes a tire sensor mounted on a tire and a sensor receiver mounted on the vehicle body side are mounted. For example, Japanese Patent Application Laid-Open No. 2001-352587 (Patent Document 1) has been proposed as an antenna structure necessary for this type of wireless device.

As shown in FIG. 6, the wireless receiver disclosed in Patent Document 1 has antennas 4a and 4b projecting from left and right ends of a printed circuit board 3 housed in a main body case 2, and these antennas 4a and 4b. Is connected to a predetermined circuit on the printed circuit board 3 by soldering.
As described above, the antennas 4a and 4b are integrated with the printed circuit board 3 by soldering to the circuit.
Since it is most desirable that the total length of the dipole antenna is about λ / 2 of the wavelength λ of the received radio wave, the received radio wave intended for the total length of the antennas 4a and 4b (for example, a remote keyless entry system) The length of each of the antennas 4a and 4b is set to about λ / 4.

By the way, the frequency received by the wireless receiver is different between Japan and overseas. For example, the frequency used for remote control operation in the remote keyless entry system is 300 MHz in Japan and 430 MHz in Europe. .
When receiving a radio wave with a frequency of 300 MHz, the antenna length with the best reception efficiency is 20 cm to 25 cm for each antenna element in the case of a dipole antenna.

As described above, when the frequency bands to be received are different, it is necessary to change the length of the antenna, and it is also necessary to change the matching circuit provided for matching the matching between the length of the antenna and the frequency.
Therefore, as in Patent Document 1, if the antenna and the printed board are integrated by soldering, it is necessary to newly form both the printed board and the antenna to provide a wireless receiver. In other words, it is necessary to provide a dedicated product for each frequency to be received, and each time the entire radio receiving apparatus must be redesigned and manufactured, resulting in a high cost.

Furthermore, Japanese Patent Laying-Open No. 2005-45625 (Patent Document 2) proposes a wireless receiver having a printed circuit board and an antenna electrically connected to the printed circuit board in a case. Since the antenna is integrally formed on the wall surface of the case, the physique of the keyless entry receiver is reduced in size while maintaining a high antenna gain.
However, since the receiving circuit generates noise, there is a problem in that separate shielding must be performed in order to reduce the influence of noise on the peripheral circuit. As in the case of Patent Document 1, when the reception frequency band is different, it is necessary to change the length of the antenna and the matching circuit.

JP 2001-352587 A Japanese Patent Laid-Open No. 2005-45625

  The present invention has been made in view of the above problems. When the frequency to be received changes, only the module having the antenna corresponding to the frequency is replaced, and the main printed circuit board connected to the vehicle side by electric wire is shared. It is an object of the present invention to reduce the cost and reduce the number of parts of the entire apparatus by eliminating the need to separately provide a means for reducing noise generated in the receiving circuit.

In order to solve the above problems, the present invention provides:
An in-vehicle wireless receiver that wirelessly receives a signal from an external device,
It has a receiving module mounted on the main printed circuit board,
The receiving module is a plate-like antenna that combines the functions of a receiving module substrate, a side wall portion protruding from at least one side edge of the receiving module substrate, and a shield plate having an upper wall portion covering the upper portion of the receiving module substrate. With
On the receiving module substrate, a power feeding pattern to be connected to the side wall portion of the plate antenna, and a wireless receiving circuit to be connected to the power feeding pattern are provided,
With the receiving module mounted on the main printed board, the lower end of the side wall portion of the plate antenna is connected to the ground circuit of the main printed board, and the wireless receiving circuit is connected to the receiving circuit of the main printed board. An in-vehicle wireless receiver characterized by being configured as described above is provided.

  It is preferable to form a matching circuit between the power feeding pattern and the wireless receiving circuit on the receiving module substrate, and to achieve matching when the received frequency and the plate antenna do not match somewhat.

As described above, when the receiving module board provided with the antenna is formed separately from the main printed circuit board and attached to the main printed circuit board, when the receiving frequency is different, the receiving module including the corresponding antenna is provided. It can be mounted on a common main printed circuit board.
That is, as a receiving module board, a plurality of types corresponding to the frequency provided with a plate-shaped antenna corresponding to different frequencies and the matching circuit corresponding to the plate-shaped antenna are prepared. By selecting a required receiving module board from among them and attaching it to a mounting portion formed on the shared main printed board, a frequency-compatible radio receiving apparatus can be easily manufactured. Specifically, only the receiving module substrate may be different between domestic and overseas. In addition, since the receiving module includes the radio receiving circuit and the antenna, both the radio receiving circuit and the antenna can be exchanged only by exchanging the receiving module.
Furthermore, since the plate-like antenna provided in the receiving module has a shape that covers the side and the upper part of the receiving module substrate, it can also function as a shield plate for the receiving module substrate.

The plate-like antenna is a plate-like shape comprising a rectangular upper wall portion formed by bending a metal plate into an L shape, and the side wall portion formed by cutting a side portion from one end side and leaving the other end. It is preferable that the antenna has an inverted F shape, and the length of one side of the upper wall portion of the rectangular shape is about λ / 8 or an integral multiple of the reception wavelength.
As described above, when the plate-like inverted F-shaped antenna is used, the length of one side of the rectangular upper wall portion can be reduced to about λ / 8 of the reception frequency, and therefore the reception module substrate covered with the upper wall portion. If the size of the receiver module is also made smaller, the overall size of the receiving module can be reduced.

In the case where the shielding function is regarded as important, the plate-like antenna may be formed in a reverse concave shape with opposing side walls, or may be formed in a box shape erected from the four sides of the entire outer periphery of the receiving module substrate. When the shape is different from such a plate-like inverted F-shaped antenna, a gap may be formed between the lower end of the side wall except the side wall portion connected to the ground circuit of the main printed circuit board and the main printed circuit board. And you may fix to the part in which the conductor of the main printed circuit board is not formed. When the area surrounding the receiving module substrate with the plate antenna is increased in this way, the shielding function can be further enhanced, and noise generated in the receiving module can be reduced.
In addition to forming the plate antenna by bending the metal plate as described above, the plate antenna may be formed by forming a metal layer on the surface of the resin molded product by plating, vapor deposition, or the like.

The radio reception circuit provided on the reception module substrate of the reception module is formed in the radio reception IC mounted on the reception module substrate, and the pattern connected to the radio reception IC is connected to the reception circuit of the main printed circuit board. Is preferred. It is preferable that the receiving circuit on the main printed circuit board side is also formed in the mounted receiving IC.
With the above configuration, since the wireless reception circuit can be integrated with an IC, the reception module substrate and the main printed circuit board can be reduced in size.

The receiving circuit on the receiving module substrate of the receiving module may be connected to the main printed circuit board by soldering via a terminal pin or by connector connection.
The receiving circuit of the main printed circuit board electrically connected to the module side wireless receiving circuit is connected to the wire harness through a connector mounted on the main printed circuit board.

The above-described in-vehicle wireless receiver of the present invention receives, for example, a wireless signal from a remote keyless entry portable device possessed by a user or a wireless signal from a transmitter for monitoring air pressure of tires mounted on a vehicle. It can use suitably for what.
Furthermore, the vehicle-mounted antenna structure of the present invention is also suitably used as a receiver for GPS, VICS, ETC, and the like.

  In the case of receiving a radio signal from a portable device for remote keyless entry, it is preferable that the wireless device is accommodated in a keyless receiver unit mounted in a body-side instrument panel or the like. In this case, the keyless receiver unit can be made larger than the keyless receiver unit when it is mounted on the door side, and even if the receiving module board is protruded vertically from the main printed board, it can be accommodated in the keyless receiver unit. it can.

As described above, in the present invention, the receiving module in which the plate-like antenna is attached to the receiving module board is formed separately from the main main printed board and is attached to the main printed board. While it can be shared, by manufacturing the receiving module according to the frequency of the received radio wave, only the receiving module board corresponding to the received radio wave can be selected and attached to the main printed board to manufacture the in-vehicle wireless receiver Can do. As a result, costs can be reduced and manufacturing speed can be increased.
In addition, since the receiving module has a plate antenna attached thereto, the plate antenna can function as a shield plate, and noise generation from the receiving module to the peripheral circuit can be prevented or reduced.
Further, when the plate-like antenna is a plate-like inverted F-shaped antenna, the length of one side of the square of the upper wall portion of the plate-like antenna is set to about λ / 8 with respect to the wavelength λ of the frequency of the received radio wave. Therefore, the plate antenna can be downsized.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B show a first embodiment.
The in-vehicle wireless reception device 10 that wirelessly receives a signal from an external device includes a reception module 20 mounted on a main printed circuit board 11, and the reception module 20 includes a reception module substrate 21 and the reception module substrate 21. A plate-like antenna 22 having a function of a shield plate having a side wall portion 22a protruding from at least one side edge of the first and the upper wall portion 22b covering the entire upper portion of the receiving module substrate 21 is provided.

The plate-like antenna 22 of the receiving module 20 is formed by bending a metal plate into an L shape as shown in FIGS. 1 and 2, cutting the side portion from one end side and leaving the other end as shown in FIG. 2. It is set as the shape of the antenna of the reverse F shape which consists of the side wall part 22a and the square upper wall part 22b.
That is, the plate-shaped antenna 22 is provided with a side wall portion 22a having an inverted L-shaped cross section, and is formed of a portion having only the upper wall portion 22a without the side wall portion 22a. The length of one side of the upper wall portion 22b is about λ / 8 of the reception wavelength.

  The reception module substrate 21 of the reception module 20 is formed in a rectangular shape that is substantially the same shape as the upper wall portion 22b of the plate-like antenna 22, and the upper wall portion 22b covers the entire upper area of the reception module substrate 21. An opening 21a that penetrates and fixes the side wall portion 22a of the plate antenna 22 is provided on one side of the receiving module substrate 21, and a power feeding pattern 24 that reaches the tip of the opening 21a is formed on the upper surface of the substrate. The plate-like antenna side wall 22a and the power supply pattern 24 are soldered to the plate-like antenna 21a and fixed to the plate-like antenna 22 and the receiving module substrate 21.

A matching circuit 23 and a wireless reception circuit IC 26 are mounted on the reception module substrate 21, and the matching circuit 23 is connected to the power feeding pattern 24, and the matching circuit 23 is connected to the wireless reception circuit IC 26 via the power feeding pattern 25. is doing.
The wireless reception circuit IC 26 includes a wireless reception circuit that performs reception processing such as filter processing and demodulation processing on a wireless signal received by the plate antenna 22, and the matching circuit 23 has a frequency for receiving the length of the plate antenna 22. A matching circuit for matching is provided.

  As shown in FIG. 1, the main printed circuit board 11 to which the receiving module 20 having the above-mentioned configuration is mounted is mounted with a connector 12 connected to a vehicle side wire harness (not shown) on one side and inserted into the connector 12. Terminal pins 13 that stop and are electrically connected to the wire harness side are projected on the main printed circuit board 11. On the other side of the main printed circuit board 11, the receiving module 20 having a plate antenna 22 having a required reception frequency is mounted.

In the area of the main printed circuit board 11 on which the receiving module 20 is mounted, a mounting hole 11a for fitting the side wall 22a of the plate antenna 22 is provided, and the side wall 22a inserted into the mounting hole 11a is formed in the main printed circuit board 11. The plate-like antenna 22 is fixed to the main printed circuit board 11 while being electrically connected to the formed ground pattern 14 by soldering.
In addition, a radio reception pattern 15 is provided in the lower surface area of the mounting portion of the reception module substrate 21, and a terminal pin 26 a of the radio reception circuit IC 26 on the reception module 20 side is inserted into a pin hole formed in the radio reception pattern 15. Soldered and conductive.

The wireless reception pattern 15 provided on the main printed circuit board 11 constitutes a reception circuit of the main printed circuit board 11 and a part of the terminal pins 13 connected to the connector 12 via the microcomputer 18 mounted on the main printed circuit board 11. Connected.
In this way, the radio reception IC 26 of the reception module 20 and the radio reception pattern 15 of the main printed circuit board 11 are electrically connected, and the plate antenna 22 is electrically connected to the ground pattern 14 of the main printed circuit board 11.
Alternatively, a LAN transceiver (not shown) may be used in place of the wireless reception IC 26, and the LAN transceiver may be interposed between the microcomputer 18 and the terminal pin 13 connected to the connector 12, so that the microcomputer 18 and the LAN transceiver are connected via the LAN. Good.

  In the radio receiving apparatus having the above-described configuration, the receiving module 20 is mounted on the main printed circuit board 11. Therefore, the main printed circuit board 11 can be shared, while the receiving module board 21 has a plate shape corresponding to the frequency to be received. When a plurality of types of reception modules 20 including the antenna 22 and the matching circuit 23 suitable for the antenna 22 are prepared, the reception module including the plate antenna 22 suitable for the frequency received by the wireless reception device 10 is prepared. 20 can be attached to the main printed circuit board 11.

  In addition, the antenna of the receiving module 20 is a plate-like inverted F-type antenna 22 and the upper wall portion 22b covers the entire upper area of the receiving module substrate 21, so that the function of a shield plate can be given. . As a result, noise from the receiving module 20 to the peripheral device can be reduced, and noise from the peripheral device to the receiving module 20 can also be reduced.

  Further, since the upper wall portion 22b of the plate-like inverted F-shaped antenna 22 has a rectangular shape, the length of one side thereof can be formed to be about λ / 8 with respect to the wavelength λ of the frequency of the received radio wave. The size of the inverted F-shaped antenna can be reduced.

Note that the plate-like inverted F-shaped antenna 22 is not limited to the above-described embodiment, and as shown in FIG. 3A, the opposite side of the upper wall portion 22b that contacts the side wall portion 22a is bent and opposed. It is good also as a structure which provided the side wall part 22c. The side wall portion 22 c has a size having a gap with the surface of the receiving module substrate 21. With this shape, the shielding function can be enhanced.
Further, as shown in FIG. 3B, a box-shaped resin molded product is provided, and the surface of the resin molded product is plated to form a metal layer 22 ′ indicated by cross diagonal lines in the figure. In the side wall portion, only a part of the metal layer is provided to the lower end, while the remaining portion is the metal layer 22 ′ up to the region not reaching the receiving module substrate 21.

FIG. 4 shows a second embodiment. In the second embodiment, the wireless reception device 10 of the first embodiment is applied to a remote keyless entry system (RKE).
Specifically, a keyless receiver unit 51 including a receiving antenna that receives a radio signal from a portable device 52 possessed by a user is mounted in an instrument panel of the automobile 50.
The keyless receiver unit 51 accommodates a wireless receiver 10 in which a receiver module 20 is incorporated in the main printed board 11 shown in FIGS.

  Since the keyless receiver unit 51 is mounted in the instrument panel, the keyless receiver unit 51 can be made larger than a conventional keyless receiver unit mounted on a door. Therefore, the radio receiving device 10 accommodated in the keyless receiver unit 51 can be accommodated as a configuration in which the receiving module 20 is erected from the main printed circuit board 11, and the receiving module 20 and the main printed circuit board 11 can be accommodated. It can be accommodated even if the area is relatively large. Therefore, the length of the plate-like inverted F-shaped antenna 22 provided in the receiving module 20 is increased, and the length is about λ / 8 with respect to the wavelength (λ) transmitted from the user's portable device 52. Thus, reception performance can be improved.

FIG. 5 shows a third embodiment. In the third embodiment, the wireless receiver 10 of the first embodiment is used for reception from a tire pressure sensor (TPMS sensor) mounted on a vehicle tire.
More specifically, TPMS sensors 56A to 56D for detecting tire air pressure are attached to the front and rear, left and right four tires 55 attached to the vehicle 50, and detection signals from these TPMS sensors 56A to 56D are received. Receiver units 57A to 57D are mounted in a tire house near the tire. Each of the receiver units 57A to 57D accommodates the main printed circuit board 11 on which the receiving module 20 having the plate-like inverted F-shaped antenna 22 of the first embodiment is mounted. The detected values of the TPMS sensors received by the receiver units 57A to 57D are connected to the air pressure monitoring ECU 59 via harnesses 58A to 58B arranged in the vehicle.

1 shows a first embodiment of the present invention, in which (A) is a schematic perspective view, and (B) is a schematic front view. FIG. The plate-shaped inverted-F antenna of the receiving module of 1st Embodiment is shown, (A) is a perspective view, (B) is a front view of (A), (C) is a right view of (A). . (A) (B) is drawing which shows the modification of a plate-shaped antenna. It is a perspective view which shows 2nd Embodiment. It is a perspective view which shows 3rd Embodiment. It is drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 In-vehicle wireless receiver 11 Main printed circuit board 12 Connector 14 Ground pattern 20 Receiving module 21 Receiving module board 22 Plate-shaped inverted F-shaped antenna 22a Side wall 22b Upper wall 23 Matching circuit 26 Wireless receiving IC

Claims (7)

An in-vehicle wireless receiver that wirelessly receives a signal from an external device,
It has a receiving module mounted on the main printed circuit board,
The receiving module is a plate-like antenna that combines the functions of a receiving module substrate, a side wall portion protruding from at least one side edge of the receiving module substrate, and a shield plate having an upper wall portion covering the upper portion of the receiving module substrate. With
On the receiving module substrate, a power feeding pattern to be connected to the side wall portion of the plate antenna, and a wireless receiving circuit to be connected to the power feeding pattern are provided,
With the receiving module mounted on the main printed board, the lower end of the side wall portion of the plate antenna is connected to the ground circuit of the main printed board, and the wireless receiving circuit is connected to the receiving circuit of the main printed board. An in-vehicle wireless receiver characterized by being configured as described above.   While a matching circuit is formed between the power feeding pattern formed on the receiving module substrate and the wireless receiving circuit, the receiving circuit of the main printed circuit board is connected to a wire harness via a connector mounted on the main printed circuit board. The in-vehicle wireless receiver according to claim 1.   The plate-like antenna is a plate-like shape comprising a rectangular upper wall portion formed by bending a metal plate into an L shape, and the side wall portion formed by cutting a side portion from one end side and leaving the other end. The in-vehicle wireless receiver according to claim 1, wherein the antenna is an inverted F-shaped antenna, and the length of one side of the upper wall portion of the rectangular shape is about λ / 8 or an integral multiple of the reception wavelength. As the receiving module substrate, a plurality of types corresponding to the frequency provided with the plate antenna corresponding to different frequencies and the matching circuit corresponding to the plate antenna are prepared,
4. The in-vehicle wireless reception device according to claim 1, wherein the plurality of types of reception module substrates are selected and attached to an attachment portion formed on the main printed circuit board. 5.   The wireless reception circuit provided on the reception module substrate is formed in a wireless IC mounted on the reception module substrate, and a circuit connected to the wireless IC is connected to the reception circuit of the main printed circuit board. The in-vehicle wireless receiver according to any one of claims 1 to 4.   6. The external device comprises a remote keyless entry portable device possessed by a user or a tire sensor attached to a tire, and receives a radio signal from the portable device or sensor. The in-vehicle wireless receiver according to claim 1.   A keyless receiver unit that receives a radio signal from the portable device for remote keyless entry is mounted on a body side of a vehicle, and a main printed board including the receiving module substrate is accommodated in the keyless receiver unit. 6. The on-vehicle wireless reception device according to 6.

Images