JP3326332B2 - Inner mirror - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner rear view mirror (hereinafter, simply referred to as an inner mirror), and more particularly, to an inner rear view mirror provided with an antenna for receiving a radio wave emitted from a transmitter of a remote control device provided in a vehicle. This is related to the inner mirror.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a remote control device for locking and unlocking a door by remote control from a position outside a vehicle. The transmitter of the device stores a preset identification code, and transmits the identification code based on the operation of an operation button provided on a key or the like.

On the other hand, the receiver of the above-mentioned device is provided in an automobile, generally in an instrument panel or under a seat. The receiver has a built-in antenna. The receiver receives the identification code transmitted from the transmitter via the antenna, and compares the identification code with a preset and stored identification code. When the identification code matches the discrimination code, the receiver outputs a signal corresponding to locking / unlocking, and locks / unlocks the door based on each signal.

[0004] However, since the above-mentioned antenna of the receiver is provided in the instrument panel, under the seat, or the like, the radio wave from the transmitter receives the electromagnetic shielding effect of the vehicle body. Therefore, the receiving sensitivity of the antenna is not good.

[0005] Therefore, it is conceivable that the antenna is provided on the roof of the vehicle so that the radio wave from the transmitter is not affected by the electromagnetic shielding effect of the vehicle body. For example, actual Kaihei 7
The antenna disclosed in -9653 is a telescopic rod antenna, and is housed in a mirror supporting portion that supports a mirror main body of an inner mirror provided in a vehicle. In use, the antenna extends downward along the glass surface of the windshield.

The antenna disclosed in Japanese Utility Model Laid-Open No. 3-94816 is formed by bonding a conductive material in a predetermined pattern to a plate provided on the back of an inner mirror in a vehicle.

[0007]

However, the antennas disclosed in Japanese Utility Model Laid-Open No. 7-9653 and Japanese Utility Model Laid-Open No. 3-94816 do not allow the radio waves from the transmitter to receive the electromagnetic shielding effect of the vehicle body. Therefore, the receiving sensitivity of the antenna is improved, but there is a problem in appearance design and the like, which is not preferable. In particular, since the antenna disclosed in Japanese Utility Model Laid-Open No. 7-9653 is a rod antenna,
It has to be expanded and contracted after each use, which is very troublesome.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an antenna which can be configured at a low cost and can secure a wide operating area of a receiver without deteriorating the external design. To provide an inner mirror provided with the same.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, the invention according to claim 1 is directed to a housing having a housing recess formed therein and a reflector for reflecting light disposed in an opening of the housing. An inner mirror provided with a pattern formed on the circuit board supported by the housing recess of the housing, an antenna for receiving a radio wave transmitted from a transmitter, and a pattern formed on the circuit board. A receiving circuit for inputting a received signal from the antenna, the grounded conductor layer formed on the circuit board,
The antenna was used as the ground plane.

According to a second aspect of the present invention, there is provided a reflector provided in a housing having an accommodation recess formed therein and an opening of the housing, wherein the reflectance of the light is changed according to the amount of light from the rear of the vehicle. And an inner mirror having a switching circuit for switching the reflectance of the reflector, an antenna formed in a pattern on a circuit board supported by the housing recess of the housing, and receiving a radio wave transmitted from a transmitter. A receiving circuit for inputting a received signal from the antenna formed in a pattern on the circuit board ,
The conductor layer formed on the circuit board and grounded is connected to the antenna
Ground plate.

[0011] I slave, according to the invention described in claim 1,
The antenna is formed in a pattern on a circuit board supported in the housing recess of the housing, and receives an electric wave transmitted from the transmitter. The reception circuit inputs a reception signal from an antenna formed in a pattern on a circuit board. Also,
The ground plane of the antenna is a grounded conductor formed on the circuit board.
It is composed of layers.

According to the second aspect of the present invention, the antenna is formed in a pattern on the circuit board supported by the housing recess, and receives the radio wave transmitted from the transmitter. The reception circuit inputs a reception signal from an antenna formed in a pattern on a circuit board.

[0013] Also, the base plate of the antenna is constituted by a conductor layer which is formed on the circuit board ground.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 2 shows an electrical configuration of a remote control device 1 for remotely locking and unlocking a door (not shown) of a vehicle. The portable transmitter 2 is provided with an operation switch 2a. The transmitter 2 operates based on the operation of the operation switch 2a.
After reading an identification code stored in a memory (not shown) in advance and modulating the identification code, the modulated identification code is transmitted to a receiver 4 accommodated in an inner mirror 3 described later.

The receiver 4 includes an antenna 5 and a receiving circuit 6. The receiving circuit 6 receives the identification code transmitted from the transmitter 2 via the antenna 5, demodulates the received identification code, performs waveform shaping, that is, digitizes the received identification code, and outputs it to the processing circuit 7.

The processing circuit 7 is provided with a memory (not shown) therein, and stores a discrimination code in advance. Upon input of the identification code from the receiving circuit 6, the processing circuit 7 reads the identification code stored in the memory, and compares the identification code with the identification code. Then, the processing circuit 7 outputs a drive signal to the actuator 8 only when the two codes match. The actuator 8 is driven based on a drive signal from the processing circuit 7, and the drive locks or unlocks each door of the automobile.

Next, the receiver 4 provided on the inner mirror 3
Will be described. FIG. 1 shows an inner mirror 3 having an automatic anti-glare function. This automatic anti-glare function is to detect the dazzling light of the headlights of the vehicle behind the vehicle by a sensor (not shown) of the inner mirror unit at the time of driving at night, etc., and to automatically reduce the reflected light of the inner mirror. is there.

A stay 9 of the inner mirror 3 is fixed to a lower front surface of a roof (not shown) of the automobile. The stay 9 is hollow and has a receiving circuit 6 inside.
A connection cord 10 for connecting the power supply and the processing circuit 7 is accommodated. Further, the mirror body 11 is rotatably supported on the stay 9 within a predetermined range. The driver or the like operates the mirror body 11 to secure the view behind the automobile.
Is rotated and adjusted within the range.

The mirror body 11 includes a housing 12,
It comprises a mirror module 13 as a reflector, a frame 14, a circuit board 15, and optical sensors not shown (that is, an ambient light sensor and a rear light sensor). The housing 12 has a curved shape, and a housing recess for housing the circuit board 15 and the like is formed therein. In the opening 12a on the front side of the housing 12,
A frame 14 for supporting a mirror module 13 having substantially the same shape as the opening 12a is attached. The mirror module 13 has a structure in which an EC function thin film in which an electrode / reflection film, a reduction coloring film, an ion conductive film, and the like are joined is sandwiched by glass. Therefore, when the mirror module 13 is energized, the reflectivity of the mirror surface changes due to electrochemical oxidation and reduction reactions, and the string protection function is automatically exhibited. The circuit board 15 includes an automatic switching circuit 16 including a comparison circuit for comparing the output values of the two types of optical sensors and a drive circuit for switching between string protection and non-string protection based on the detection results. In addition, the receiving circuit 6 is formed. The circuit board 15 is fixed to a mounting portion (not shown) protruding from the inner wall surface of the housing 12 with screws or the like. Also, frame 1
A push switch 17 for manually switching between string protection and non-string protection is provided at the center of the front surface of 4.

In the present embodiment, the circuit board 15 is
As shown in FIG. 3, for example, a two-layer printed wiring board having a copper foil attached thereto,
(Side), a conductor layer 18 is formed. On the surface on which the conductor layer 18 is not formed, a conductor wiring pattern is formed.
Are soldered, for example, various electronic components 19 such as an IC chip, a chip resistor, and a chip capacitor. Further, a pattern having a function as the antenna 5 is formed in a part of the conductor wiring pattern.
The antenna 5 is made of the same material as the conductor wiring patterns of the circuits 6 and 16 and is formed at the same time. The various electronic components 19 are connected to the conductor layer 18 and the connector 20 mounted on the conductor layer 18 through through holes (not shown) formed through the circuit board 15 as appropriate. The connector 20 is connected to a connection cord 10 housed in the hollow portion of the stay 9. And the receiving circuit 6
Is connected to the processing circuit 7 via a connector 20 and a connection cord 10.

The antenna 5 formed in a pattern on the circuit board 15 has a substantially L-shape on the outer periphery of the board 15 as shown in FIG. By the way, antenna 5
It is called a printed monopole antenna because of its shape. On the other hand, the circuit board 1
The conductor layer 18 formed on the ground 5 and grounded via the connector 20 and the connection cord 10 becomes a ground plate (earth plate). Therefore, the grounded conductor layer (ground plate) 18 has a mirror effect, and an image antenna is formed separately from the antenna 5. Therefore, the gain of the antenna 5 is improved. or,
The length of the antenna 5 is determined by the frequency of radio waves used for the remote control device 1 and the like.
For example, when using a radio wave of a frequency of 300 MHz,
The length of the antenna 5 is set to approximately １ ／ of the wavelength λ of the radio wave to be used (in this case, about 1 m), for example, 25 cm
Is set to The antenna 5 receives the transmitted radio wave and supplies the received signal to a receiving circuit 6 including various electronic components 19 from a feeding point N shown in FIG.

In the present embodiment, the radio waves received include, in addition to the radio waves from the transmitter 2 of the remote control device 1, a television broadcast wave, a radio broadcast wave, and the like. It is also possible to receive by the antenna 5 of the form described above. However, since each broadcast wave uses various frequency bands, it is necessary to receive radio waves of each frequency band on average. As a result, depending on a certain frequency band, the receiving sensitivity is lower than the optimum receiving sensitivity. Conversely, in order to obtain a suitable receiving sensitivity, it is necessary to change the length of the antenna 5 depending on the frequency band.

However, since the radio wave from the transmitter 2 of the remote control device 1 uses a single frequency, the length of the antenna 5 only needs to be adjusted to the single frequency. Can be easily determined.

As described above, the features of this embodiment will be described below. (1) Since the antenna 5 of the receiver 4 is provided inside the inner mirror 3, the radio wave from the transmitter 2 does not receive the electromagnetic shielding effect of the vehicle body, and the reception sensitivity of the antenna 5 is very good.

(2) Since the antenna 5 is housed inside the inner mirror 3, the appearance design is not hindered. (3) Since the antenna 5 is formed in a pattern on the circuit board 15 and does not require a component as an antenna, the cost can be reduced. Also, the number of assembling steps can be reduced.

(4) Receiving circuit 6 inside inner mirror 3
Since the antenna 5 is directly connected to the circuit 6, the configuration can be made without using a coaxial cable, and the cost can be reduced.

(5) The antenna 5 can easily cope with the frequency of radio waves used for the remote control device 1 depending on the type of the vehicle or the like only by adjusting its length. (6) Conductive layer 18 formed on circuit board 15 and grounded
Is a ground effect (mirror effect), thereby improving the gain of the antenna 5.

(7) Since the receiving circuit 6 and the automatic switching circuit 16 are formed on the circuit board 15 in common, the number of parts and the number of assembling steps can be reduced. (8) The antenna 5 is formed simultaneously with the conductor wiring patterns of the receiving circuit and the automatic switching circuits 6 and 16. Therefore, the configuration can be simplified and the number of assembling steps can be reduced.
Also, space efficiency is good.

The present invention may be modified as follows, and the same operation and effect can be obtained in such a case. (1) In the above embodiment, the antenna 5 is formed in a pattern on the circuit board 15 formed so as to share the auto switching circuit 16 and the receiving circuit 6, but the auto switching circuit 16 and the receiving circuit 6 are separately supported. Alternatively, the antenna 5 may be formed in a pattern on at least one circuit board. Alternatively, only a receiver may be housed in a general inner mirror, and may be formed in a pattern on a circuit board on which a receiving circuit is formed.

(2) In the above embodiment, the processing circuit 7
Is provided inside the vehicle body separately from the inner mirror 3,
It may be housed in the inner mirror 3. Further, the processing circuit 7 may be integrated with the receiving circuit 6. The processing circuit 7
The antenna 5 may be formed in a pattern on a circuit board on which is formed.

(3) In the above embodiment, the circuit board 15
The conductor layer 18 formed and grounded is grounded (ground plate).
However, it may be constituted by a conductive member separately from the circuit board 15.

(4) In the above embodiment, the antenna 5
Is composed of a printed monopole antenna, but is not limited to this. For example, a printed dipole antenna, a printed inverted F antenna, or the like may be used.

(5) In the above embodiment, the antenna 5
Is used for the receiver 4 of the remote control device 1 that locks and unlocks the door of the automobile, but is not limited to this. For example, it may be used for a receiver of a remote control device that starts and stops the engine.

Although the embodiments of the present invention have been described above, technical ideas other than the claims that can be grasped from the embodiments will be described below together with their effects. (1) The inner mirror according to claim 1 or 2 , wherein the antenna is formed simultaneously with the conductor wiring pattern on the circuit board. By configuring the antenna in this way, the antenna can be simply configured and the number of assembling steps can be reduced. Also, space efficiency is good.

[0035]

According to the first and second aspects of the present invention, it is possible to provide an inner mirror provided with an antenna capable of securing a wide operating area of a receiver without compromising the external design and at a low cost. it can.

Also , the gain of the antenna can be improved without using extra parts.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an inner mirror according to the present embodiment.

FIG. 2 is an electrical configuration diagram of a remote control device.

FIG. 3 is a sectional view of a main part of an inner mirror.

[Explanation of symbols]

2 ... Transmitter, 5 ... Antenna, 6 ... Receiving circuit, 12 ... Housing, 12a ... Opening, 13 ... Mirror module as reflector, 15 ... Circuit board, 16 ... Automatic switching circuit as switching circuit, 18 ... Conductor layer.

Claims (2)

(57) [Claims] A housing (1) having an accommodation recess formed therein.
2) and an inner mirror provided with a reflector (13) for reflecting light disposed in an opening (12a) of the housing (12), on a circuit board supported by a housing recess of the housing (12). An antenna (5) formed in a pattern on (15) and receiving a radio wave transmitted from a transmitter (2); and an antenna (5) formed in a pattern on the circuit board (15). and a receiving circuit for inputting a received signal (6), a conductor layer which is grounded is formed on the circuit board (15)
An inner mirror having (18) as a ground plane of the antenna (5) . 2. A housing (1) having an accommodation recess formed therein.
2) and a reflector (13) which is disposed in the opening (12a) of the housing (12) and changes the reflectance of the light according to the amount of light from behind the vehicle, and the reflector (13) In an inner mirror provided with a switching circuit (16) for switching reflectance, a pattern is formed on a circuit board (15) supported by a housing recess of the housing (12) and transmitted from a transmitter (2). with the antenna (5) for receiving radio waves, said circuit board and a reception circuit for inputting a reception signal from the antenna formed in the pattern (15) (5) (6), said circuit board ( 15) Grounded conductor layer formed on top
An inner mirror having (18) as a ground plane of the antenna (5) .