JPS6237476A - Keyless entry apparatus for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

3. Correction of the invention [Industrial field of application] The present invention relates to a keyless entry device for a vehicle, particularly a vehicle that automatically locks and unlocks the door by receiving a radio signal from a transmitter. The present invention relates to a keyless entry device for use in the United States. [Prior Art] In recent years, a keyless vehicle 1 has been developed that automatically locks and unlocks doors by receiving a code signal using weak radio waves from a transmitter instead of a door lock device that uses a general key.
The entry device is mainly mentioned in luxury cars. Such a keyless engine for a vehicle does not only function to open or open the door, but also perform functions such as opening/closing a compartment, opening a window, or preventing theft. Various additional functions such as an alarm function can also be performed, and many conveniences can be provided to the vehicle user name. By the way, such a 21-less soil removal device for vehicles from iY is also shown in FIG. Jζ', radio waves from the transmitting antenna 12 of the transmitter 10 (6 in the illustrated example)
The T1-do signal wing by 0HIIz) is attached to the ball ann 7s16C'' for receiving radio broadcast waves provided on the surface of the Φ body 14.
The received signal is input to the distributor 20 via the feeder line 18 (1). This distributor 20 has a radius 7j-
The received signal is distributed and output to a keyless engine 22 and a keyless engine signal receiver 24. As a result, the RPH is output from the speaker 2G of the radio 22, and the control signal 28 for locking and unlocking the door is output from the keyless entry signal receiver 24. However, conventional vehicle keyless systems like this one
Since this device divides the reception signal of the radio A broadcast wave reception antenna into two parts, the sensitivity of the radio broadcast wave band is approximately 3.
This results in a dB drop. In addition, since the antenna for receiving radio broadcast waves is adjusted to center on the radio broadcast wave band, especially the 1M band (1G/90Htlz), a typical vehicle keyless entry device propagates the ]-code signal. The carrier frequency of the radio waves used for (
60811Z), it may not be possible to obtain 41-light sensitivity. Furthermore, in areas with strong electric fields, such as near transmitting stations for FM broadcasting or TVrli transmission, there is strong input interference, so keyless 1
Filtering or
There were problems such as the need to take measures such as wrapping. Therefore, it is possible to receive the second-order signal by radio waves from the transmitter (
) for vehicles that automatically lock doors, etc.: Keyless 1
It is necessary to install a dedicated antenna for the steering device, and although the ball antenna protruding from the car body shows favorable reception characteristics, it is destined to always be treated as a nuisance when it comes to car body design. Ta. In addition, even in actual use, such ball antennas are susceptible to damage such as bending and bending.

[Ball antennas have had various problems such as being easily stolen, being the target of mischief or theft, and generating unpleasant wind noise when driving at high speeds. It is unrealistic to install a new crosspiece. Therefore, some conventional killless entry devices for vehicles are characterized in that the reception loop antenna is provided around the actuator handle of the door as a molding (Japanese Utility Model Publication No. 59-44861). Such a keyless entry device for a vehicle has the advantage of being able to reliably catch radio waves from a transmitter without changing the shape of the vehicle body, etc. [Problems to be Solved by the Invention J] Prior Art Problems However, such conventional improved keyless entry devices for vehicles have relatively low sensitivity, and furthermore, due to their directional characteristics, it is difficult to use the transmitting loop antenna as the receiving loop antenna from very close distances (approximately 10 cm). Therefore, it is possible to take advantage of the feature of this type of vehicle keyless entry device that it can automatically lock and unlock the door from a certain distance from the vehicle body. Purpose of the Invention The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide a keyless keyless for a vehicle that does not impair the appearance of the vehicle body and has excellent directional characteristics. [Means for Solving the Problems] In order to achieve the above object, the keyless entry device for a vehicle according to the present invention includes at least a surface current detecting device on the vehicle body. t) Two pickups are provided, and the radio wave reception from the transmitter is characterized in that the surface current induced in the vehicle body by the radio waves is detected by the pickups. [Function] As is clear from the above-mentioned configuration. Furthermore, according to the vehicle keyless entry device according to the present invention, since radio wave reception is performed by a pickup that detects surface current induced in the vehicle body, the pickup can be built into a 4.1 width body, and the aesthetic appearance of the vehicle body is improved. In addition, two or more pickups are installed on the vehicle body.
Since the directional characteristics of the vehicle are complemented, it is possible to use a non-directional vehicle keyless entry system in one place.Furthermore, it is possible to install a dedicated pickup for the vehicle keyless entry system. By setting the receivable frequency of the pickup to a narrow band, it is possible to reliably eliminate interference radio waves from broadcasting stations or power transmission lines. An example will be explained.Pickup installation position Figures 21 and 26 show the process of determining the most efficient pickup installation position by investigating the surface current distribution characteristics of the vehicle body. indicates that when the radio wave W from the transmitter passes through the car body B made of metal conductors, a surface current I centered on the intensity of the electromagnetic waves is induced in each part of the car body. The present invention targets radio waves around 5QHIIz, which belong to a relatively high frequency band among these radio waves and are used for transmitting the []-code signal of a vehicle key locking device. This method measures the induced current distribution of the vehicle body in the high frequency band of The current intensity was measured at each point.That is, using a probe based on the same principle as the pickup installed on the desired vehicle body part, which will be described later,
] - The surface current was measured by moving the probe over the entire surface of the car body, changing direction at each point. FIG. 22 shows a block [-1-b[
] is shown, in which a loop coil 42 is fixed inside a case/10 made of a conductor to avoid mixing of radio waves from the outside. And the case 4
A part of the loop coil 42 is exposed to the outside through the opening 40a, and the exposed portion of the loop coil 12 is brought close to the surface of the vehicle body to attach the loop coil 42 to the outside. The magnetic flux generated from the surface current is transferred to the loop coil 4.
It consists of a detection configuration. A portion of the loop coil 42 is connected to the case 40 by a shorting wire 44, and an output end 46 is connected to a core wire 50 of a coaxial cable 48. In addition, a capacitor 52 is installed in a part of the loop coil 42.
The frequency of the loop coil 42 can be made to resonate at the desired frequency to be measured (in the example shown, 60M!17) to improve the pickup efficiency. In this way, the probe P can be moved along the surface of the vehicle body B. By moving the probe P and rotating its angle at each measurement point, it is possible to accurately determine the surface mainstream distribution and its direction on the vehicle body surface. In FIG. is amplified,
The output claw pressure is measured by the high frequency voltage amplifier 56. This oil output pressure is read by the meter indication value of the measuring device 56, and the voltage corresponding to this meter indication value is recorded by the XY recorder 58 as a surface current distribution in each part of the vehicle body. A signal indicating each position of the vehicle body is inputted to the XY recorder 58 from a potentiometer 60, and it is possible to know the high frequency pickup current at each position. FIG. 23 shows the deviation angle θ between the high-frequency surface current I and the loop coil 42 of the pickup, and as shown in the figure, the current
The magnetic flux φ in the loop coil 71:? By interlinking, an output voltage V is generated in the loop coil 42, and the maximum voltage is ( By rotating Bu [] - Bu F) at six measurement points, the direction of the surface current I when the maximum voltage is increased by 1!1 can be determined. Figures 25 and 26 show the magnitude of the high-frequency surface current generated in each part of the car body by adding 3) to the frequency of 60 and 17 obtained from the measurement results with the probe P mentioned above and the ti calculator from both Simil and Shicon. The ripples indicate the direction,
As is clear from Fig. 25, the surface current has a high density at the edges of the car body surface area, and shows an extremely low density distribution at the center of the flat plate area.
'. Furthermore, as shown in the current directions in FIG. 26, it is understood that each current number is concentrated in a direction parallel to the end edge of the vehicle body or in the direction of the connecting portion of each flat plate portion. 8 J3, considering the range of current reduction under 6 dB LS that can be reduced due to the separation distance from the edge of the metal tP plate of the car body (the surface current is low and the sensitivity is actually good), each In terms of characteristics, if the distance is 6.0 cm or less from the edge, it is possible to achieve extremely good sensitivity of 1q.The present invention was made based on the following findings,
In particular, two pairs of high-frequency pickups are placed in areas where surface current flows in a high density and concentration. FIG. 1 shows a first embodiment of a keyless entry device for a vehicle according to the present invention. The characteristic feature of this embodiment is that the front 1 on both sides of the vehicle body
Pick-ups 102a and 102b having the same configuration as the above-mentioned probes are arranged on the Hebilar 100a and 100b to detect the surface current flowing concentratedly in the front pillar. Here, the pickup 102 has a reception band center of 60M.
By adjusting the Hz and using an impedance matching circuit to receive only a narrow band of high-frequency surface current, the influence of interfering radio waves such as FM broadcast waves or TV broadcast waves is reduced. In this embodiment, the vehicle keyless entry device includes a transmitter 104 that is operated by the user and a receiver 106 provided on the vehicle body, and picks up surface current induced in the vehicle body by radio waves from the transmitter 104. It is detected at 102 and electrically processed by a receiver 106. The oscillator 104 includes a crystal oscillation circuit 108 having an oscillation frequency of 60 Htlz, and an RF amplifier 112 that amplifies this oscillation signal and supplies it to a transmitting antenna 110. keyless en 1
It is controlled by -ri operation. That is, the transmitter 1071 includes a key-operated switch 114 that can be turned on and off by the user, and the code setting circuit 116 receives a desired electrical input signal according to the operating procedure or timing of the switch 114. Attach. The output of the code setting circuit 116 is converted into a desired electrical signal by a coding circuit 118, and this coded signal is sent to the RF amplifier 11 via a modulator 20.
Controls the output of 2. Therefore, according to the illustrated transmission 5104, a desired modulated keyless entry signal is wirelessly propagated from the transmission antenna 110 by the user's keyless entry operation, that is, the operation of the switch 114. On the other hand, a high frequency surface current is induced in the vehicle body by the radio waves from the transmitter 104, and the pickups 102a and 102b
receives the radio-propagated keyless entry signal from this surface current, and in the receiver 106, the received signal of the pickup 102a is received as is, and the signal received by the pickup 102a is
After the received signal of 2b is corrected in phase by a phase difference correction circuit 122, it is input to a mixer 123, and the received signal mixed by the erroneous mixer 123 is supplied to an RF amplifier 124, where it is subjected to a desired amplification effect. Ru. Then, the amplified signal is sent to the H,4 combiner 126 and mixed with a local oscillation frequency signal of, for example, 59.545 MIIz from the local oscillation circuit 128, and further amplified by the intermediate frequency amplification circuit 130. This amplified signal is demodulated and detected by the detection circuit 132, and then the code set by the I/Mig path 1311 is restored. From the receiver 10G, 11. It was restored with 1,
Control signal 13 where the signal is used for other purposes such as locking or unlocking the door.
It is rolled out as a 6. FIG. 2 shows the vehicle key 1 according to this embodiment. 6 (1M117 circumference fractional band) shows the directivity characteristic of the No. 6 (1M117) circumferential fraction band.
(B) shows the characteristic curve after combining the directional characteristics of both LL picks 7'. In the same figure (△) it is clear <r, pickup 102
A has a good sensitivity characteristic on the right side of the vehicle body, and has a weak sensitivity characteristic in the longitudinal direction of the vehicle body. , 2t1.1. On the other hand, the pickup 102b has a directivity characteristic completely opposite to that of the pickup 102a, and the relationship between both pickups is that they match each other.
Two things are solved by Pv. Therefore, by combining the directional characteristics of both pickups 1020, it is possible to obtain a non-directional 141 antenna as shown in the same figure (B), which is good from any direction with respect to the car body. It becomes possible to perform the operation A=-tnosenj-. FIG. 3 shows the antenna directivity characteristics of a second embodiment of the present invention (such as this vehicle key/scanning device). In this case, the pickups are installed at both ends of the rear edge of the small rear roof.As is clear from FIG. By complementing each other's weakly sensitive parts, the directional characteristics of the vehicle keyless key 1 edge device are improved as in the first embodiment.Furthermore, FIG. A special example of the antenna orientation of such a vehicle keyless entry device is shown.What is distinctive about this embodiment is that the pickup is provided at the center of the front edge of the front roots and the center of the rear edge of the rear roof. As is clear from Figure 4, the pickup 406 provided at the center of the rear edge of the Real-7 has good directivity toward the front of the vehicle, and the pickup 500 provided at the center of the front edge of the front root has good directivity toward the rear of the vehicle. Therefore, both pickups complement each other's weakly sensitive parts to achieve good antenna directional characteristics. Fig. 5 shows a vehicle keyless system according to a fourth embodiment of the present invention. The antenna directivity characteristics of the entry device are shown.What is distinctive about this embodiment is that pickups are provided at the center of the front pillar and the rear edge of the rear roof.As is clear from Fig. 5, the front The pickup installed in the pillar has good ear directivity in the left and right direction,
Also, the pickup 4 installed in the center of the rear edge of Real-7
06 has good directivity in the front direction of the vehicle. Therefore, it is understood that both pickups complement each other's directivity. FIG. 6 shows a pickup according to the fifth embodiment of the present invention. The antenna directivity characteristics of the vehicle keyless engine system are shown.What is distinctive about the J3 in this example is that a pickup is provided on the right front pillar of the vehicle body and on the right end of the rear roof edge. As shown in Figure 6, the directional characteristics of the pickup 102b installed on the right side front 1 heavy mirror and the directional characteristics of the pickup 406b installed on the right end of the rear roof of the rear roof complement each other, and both pickups provide good antenna directional characteristics. Fig. 7 shows the AN5-I directional characteristics of the vehicle keyless entry device according to the sixth embodiment of the present invention. This is because a pickup is provided at the right end of the front edge of the front roof of the vehicle and the right side 1-rank hinge of the vehicle.As is clear from FIG. The pickup 20 provided on the hinge compensates for the directivity characteristics, and both pickups realize good antenna directivity characteristics for a vehicle keyless engine system. In the above, the case where two pickups (41) are provided on the vehicle body has been described, but the invention is not limited to this, and it is also suitable to provide three or more pickups on the vehicle body. Furthermore, the installation position of the pickup is not limited to the above embodiments, but any position n that can detect the high frequency surface current induced in the vehicle body by the radio waves from the transmitter can be used.
There may be one. Next, the structure of mounting the pickup to each part of the pickup will be explained. First, the details of the fS construction will be explained based on FIGS. 8 to 10. FIG. 8 schematically shows how the pickup according to the present invention is installed, and the high frequency pickup 102 is mounted on the ceiling.
(Supports the board) [It is built into the 1-in-1 pillar 100, and in this installation example, the high-frequency pickup 102
It affects electromagnetic pickups containing loop coils. As is clear from the cross-sectional view of FIG.
Contains 0. A windshield molding 152 is fixed to the outer surface of the vehicle body of this pillar leg plate 150.
A windshield 154 is held by this molding 152. Further, the pillar leg plate 150 is provided with weather protection on the rear side of the vehicle body.
A strip rubber 156 is fixed.
This ensures watertightness between the side glass 158 and the side glass 158. Further, a front pillar garnish 160 is attached to the pillar leg plate 150 on the side facing the vehicle.
It hides the surface and maintains the aesthetic appearance. The characteristic feature of the A3 in this installation is that the front pillar io
The high frequency pickup o is arranged in the longitudinal direction of the pillar, and in the illustrated example, the pillar leg plate 1
An electromagnetic coupling type high frequency pickup 102 is installed in the hollow interior of 50.
is inserted. As is clear from FIGS. 9 and 10, the high-frequency pickup 102 has a structure in which a loop coil 164 forming an antenna element is installed inside a case 162 made of a conductor. Although it shields magnetic flux, it has an opening 162a on the right side thereof, and the loop coil 164 is exposed from this opening 162a and is placed close to the pillar, particularly the pillar leg plate 150, where high frequency surface current flows in a concentrated manner. In the illustrated example, in order to insert the high frequency pickup 102 into the hollow rectangular column of the pillar leg plate 150, a frontage portion 150a is provided in a part of the pillar leg plate 150, and the high frequency pickup 102 is The pickup 102 is inserted into the pillar.In order to fix the case 162 of the high-frequency pickup 102 to the pillar leg plate 150, brackets 166 and 168 are fixed to both ends of the case 162 by spot welding or the like. Securely fix both brackets 166 and 168 to the pillar leg plate 150 with screws as shown.
Ru. Therefore, a3 is placed on this fixed plate, and the loop coil 1
64 is disposed at a position close to the space 11 portion 150a of the pillar leg plate 150, so that the magnetic flux caused by the high frequency surface current flowing intensively through the pillar leg plate 150 effectively interlinks with the loop coil 164. A circuit section 170 including a preamplifier and the like is built into the case 162 on the back side of the loop coil 164 described above, and power and signals for controlling the circuit are supplied to this circuit section 170 from a cable 172. Further, the high frequency detection signal detected by the loop coil 164 is taken out from the coaxial cable 174 and processed by a circuit similar to that used in the surface current distribution described above. In the illustrated example, the loop coil 164 is made of a single-turn coil, and the loop coil 164 is coated with an insulating coating so that it is placed in close contact with the pillar leg plate 150 in an electrically insulated state. A structure in which it is pressed against the edge is suitable, and the magnetic flux generated by the high-frequency surface current that flows intensively in the pillar can be efficiently linked to the loop coil 164. After the high frequency pickup 102 is installed in the front 1-pillar 100 as described above, the front 1 heavy roller garnish 160 is attached to the pillar 100, creating a structure that is no different in appearance from a normal pillar structure. Obtainable. As a result, in the illustrated example, the high-frequency surface current that flows intensively from the fluorocarbon 1 to the pillar of the automobile can be effectively detected by the loop coil arranged in the longitudinal direction of the pillar, and the amplifier can be completely removed from the outside. It is possible to reliably receive high frequency signals without being exposed to In the above installation example, an m1ifl combined type pickup is used for the high frequency pickup, but the present invention is a keyless en1 helicopter device that detects the surface current of the pillar and receives radio waves from the transmitter. () As for high frequency pickups, not only the above-mentioned electromagnetic coupling type but also the electrostatic coupling type can be used. In the case of a capacitively coupled pickup, a detection electrode is arranged along the longitudinal direction of the pillar in each of the figures described above with an air layer or an insulating layer interposed therebetween, and the electrostatic capacitance ω formed between the pillar surface and the detection electrode is A high-frequency surface current is extracted to the detection side through the signal, thereby making it possible to extract a high-frequency signal at a carrier frequency of 60 MH2f, which is normally used by a keyless entry device for signal propagation. Next, the details of the structure for attaching the pickup to the trunk lid will be explained based on FIGS. 11 to 13. In FIG. 11, the trunk hinge 200 has one end pivotally supported by the main body, and the other end fixed to the trunk lid 202, forming a pivot support for the trunk lid 202. A feature of this installation example is that a pickup 204 is provided on the trunk hinge. In this installation example, a torsion bar 206 is provided on the pivot side of the 1-rank hinge 200, and performs a moderation function to position the trunk lid 202 at the same date and time. As is well known, a watertight weather strip rubber 208 is provided between the trunk lid 202 and the vehicle body to prevent rainwater from entering through the rear glass 210. In this installation example, the pickup 204 is fixed to the outside along the longitudinal direction of the trunk hinge 200, that is, to the trunk room side, and the loop coil 212 provided inside the pickup 204 is fixed to the trunk hinge 200 in the longitudinal direction.
In this installation example, the surface current flowing through the trunk hinge 200 can be reliably and highly efficiently supplemented by the loop coil 212. The pickup 204 includes a case 2141 and a circuit section 216, as in the installation example from the front 1 to the pillar.
The opening side of 4 faces the trunk hinge 200. Then, brackets J3 (~218, 220) are fixed to both ends of the opening of the case 214, and both brackets 218.
One end of the trunk hinge 220 is firmly fixed to the trunk hinge 200 with a screw. Therefore, there is a 1-rank hinge 20 inside the case 214.
It is understood that only the magnetic flux induced from the surface current flowing in the case 214 is captured, and the magnetic flux from the outside is reliably shielded by the case 214. The Le-Broil 212 is i-Rintahi:Nji 200
It is preferable that the hinge 200 be provided along the curvature of the hinge 200 and have a shape that matches the curvature of the hinge 200. As mentioned above, the circuit unit 216 is supplied with power and signals for controlling the circuit from the loop 222, and the loop
- The high frequency detection signal taken out by the broil 212 is taken out from the coaxial cable 224 and processed by the same circuit as described above. As described above, according to this installation example, it is possible to detect the car body surface current (from the unrelated 1-rank hinge to the pickup), and to
) Therefore, it is impossible to reliably receive radio waves from the transmitter by exposing the cover of the vehicle key 1 or person 1 to the outside. FIG. 13 shows several other examples of pickups to the trunk hinge, and the same parts as in FIG. 12 are given the same reference numerals and explanations are omitted. What is distinctive about this installation @ is the trunk hinge 20
The pickup 300 is placed on the back side of the 0.
The inside of the case 302 includes a loop coil 304 and a circuit section 30 (5), including a bracket +, 3os, 31o.
It is firmly fixed to the 1-rank 200 (r) 1 side (7a). In this installation example, if the pickup 300 protrudes from the i-rank hinge 200 toward the 1-rank room side, it will not come into contact with the baggage (i!!) stored in the trunk.
It has the advantage of being ugly when it comes to frogs and scratches. Next, Figures 14 to 17 explain the details of the rent. In the figure, the ceiling board 400 is shown exposed.
T J3 (Second metal ceiling plate 4001J) Wind room 402 is connected to its peripheral edge and 1-2C to the rear glass 4011. 1
A high frequency pickup 40G is provided in an area within 6.0 cm from the edge of the gnome 402. @Similar to the installation example, pickup 406 beam 40
8. Loop coil 4101 circuit section 412° cable 41
4. Coaxial cable 416. Brackets (to 418,420
including. FIG. 16 shows a cross-sectional view of the pickup 406 fixed to the large moon plate, and the ceiling plate is connected to the roof panel 422.
The above-mentioned rear window frame 402 is fixed to one end of this roof panel 422, and the rear glass 404 is fixed to the roof panel 422 via a fastener 424 and a dam 426. 426 is uniformly attached with adhesive 428. In addition, the roof panel 422 and the rear glass 4
04, a molding 430 is fixed. In this installation example, in order to arrange the loop coil 410 of the pickup 406 to face the peripheral edge of the rear window frame 402, an opening 402a is provided in a part of the rear window frame 402, and the case 402a of the pickup 406 Insert and place. An opening 408a is provided in the resource 408 so that the longitudinal side of the loop coil 410 is exposed.
In this way, a portion of the loop 410 exposed from the case 408 made of a conductive material is exposed to the rear window frame 4.
02 and is arranged close to and opposite to the opening edge. After the pickup 406 is assembled into the exposed ceiling panel, especially the rear window frame 402, as described above,
A roof garnish 432 is fixed to the top plate, and an edge 434 is fixed to the ends of the roof plate 432 and the rear windshield gnome 402. Next, the details of the front roof installation structure of the pickup will be explained based on FIGS. 18 and 19. In this installation example, the pickup 500 is attached to the ceiling plate 400.
It is arranged in a service hole 502a of a header inner panel 502 provided at the tip of the header. As is clear from FIG. ．． 1, the freon 1-glass '154 is fixed, and as is well known, the freon 1-glass '154 is fixed.
Tsuba 50G with 1 no [-ru 508 roots panel 42
2 and ) [J-1 glass 154 are connected. The big 7 tubes 500 in this installation example have a configuration similar to that of the first embodiment, and the case has a 510° loop.
1'le 512. A circuit section 514 is included. And, the loop coil 512 of the pickup 500 is 6.0cm inward from the periphery of the inner panel 5020.
The distance range 'C' of m is fixed and the surface current of the header inner panel 5502, which is concentrated in a high density area, can be reliably detected. [Effects of the Invention ψ1 As explained below-1-, the vehicle keyless entry device according to the present invention can
Vehicle key 1 Pick up exclusively for no-entry device 2
This makes it possible to provide more than one antenna, and it becomes possible to obtain good directivity characteristics. Moreover, it is possible to avoid a decrease in radio A-broadcast receiving sensitivity due to the conventional method of dividing the radio broadcast wave receiving antenna into two parts, and also to narrow the receiving band of the pickup to reduce the influence of interfering radio waves.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a vehicle keyless entry device according to the first embodiment of the present invention, FIG. 2 is a directional characteristic diagram of a pickup used in the vehicle keyless entry device according to the first embodiment, FIG. 3 is a directional characteristic diagram of a vehicle keyless entry device according to a second embodiment of the present invention, FIG. 4 is a directional characteristic diagram of a vehicle keyless entry device according to a third embodiment of the present invention, 5 is a directional characteristic diagram of a vehicle keyless entry device according to a fourth embodiment of the present invention, FIG. 6 is a directional characteristic diagram of a vehicle keyless entry device according to a fifth embodiment of the present invention, and FIG. 7 is a directional characteristic diagram of a vehicle keyless entry device according to a fifth embodiment of the present invention. A directional characteristic diagram of a vehicle keyless entry device according to a sixth embodiment of the invention, FIGS. 8 to 10 are explanatory diagrams of a front pillar mounting structure of a pickup used in a vehicle keyless entry device according to the present invention FIGS. 11 to 13 are explanatory views of the structure of the pickup used in the vehicle keyless entry device according to the present invention and how it is attached to the trunk hinge, and FIGS. 14 to 17 are the vehicle keyless entry device according to the present invention. 18 and 19 are explanatory diagrams of the structure for attaching the rear roof of a pickup used in the vehicle keyless entry device according to the present invention, and FIG. 20 is a conventional 21 is an explanatory diagram showing the surface current I generated on the vehicle body B by the radio wave W from the transmitter, and FIG. 22 is a configuration similar to the pickup used in the present invention. Figure 23 is an explanatory diagram of a probe and its processing circuit for determining the distribution of vehicle surface current.
Fig. 24 is a characteristic diagram showing the directivity characteristics of the loop antenna in Fig. 23, and Fig. 25 is an explanatory diagram showing the surface current intensity distribution characteristics. , FIG. 26 is a diagram showing and explaining the direction of surface current. 100...Front pillar 102.204,300,406,500...Pickup 104...Transmitter 106...Receiver 200...1-rank hinge 400...Ceiling board

Claims (5)

[Claims] (1) In a vehicle keyless entry device that automatically locks and unlocks doors by receiving a code signal using radio waves from a transmitter, the vehicle body is provided with at least two pickups that detect surface current; A keyless entry device for a vehicle, wherein the radio wave reception is performed by detecting, with the pickup, a surface current induced in the vehicle body by the radio waves. (2) A keyless entry device for a vehicle according to claim (1), characterized in that the pickups are arranged along the longitudinal direction of the front pillars on both sides of the vehicle body. (3) The keyless entry device for a vehicle according to claim (1), wherein the pickup is arranged along the periphery of the vehicle roof. (4) A keyless entry device for a vehicle according to claim (1), wherein the pickup is disposed at the center of the front pillar and the rear edge of the rear roof. (5) The keyless entry device for a vehicle according to claim (1), wherein the pickup is disposed at the front roof side end and at the trunk hinge on the same side.