JPS623503A - Tv antenna system for automobile - Google Patents

Abstract

PURPOSE:To improve remarkably the directivity of an antenna and to attain the reception of a broadcast radio wave in which multi-path noise is reduced by constituting a diversity reception antenna with a ceiling part high frequency pickup and a trunk hinge part high frequency pickup having diferent directivity from each other. CONSTITUTION:Two ceiling part high frequency pickups 32-1, 32-2 and two trunk hinge part high frequency pickups 34-1, 34-2 constituting the diversity antenna are arranged. The ceiling part high frequency pickups can be arranged to the front window side as the ceiling part high frequency pickups 32'-1, 32'-2. The trunk hinge part high frequency pickups 34 consist, e.g., of electromagnetic coupling type pickups and has a structure including a loop antenna to detet the distribution of surface current of the car body similarly as the ceiling part high frequency pickups 32. Thus, a broadcast wave is received with the excellent directivity being the combination of the directivity of both the ceiling part high frequency pickups 32 and the trunk hinge part high frequency pickups 34 as the antennas.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a TV antenna device for automobiles using a high frequency pickup in a TV antenna, and in particular, to switch TV antennas based on reception conditions and select a TV antenna with optimal reception conditions. The present invention relates to an improved automotive TV antenna device that is used to receive TV broadcast radio waves.

[Prior Art] In recent years, the number of cases in which TV receivers are installed in automobiles, etc. has increased, and the automobile TVs used in this way are not only used for receiving public television broadcasts, but also for displaying various data on the vehicle. It is also used for purposes.

In this type of automotive TV, the reception signal of TV broadcasting radio waves is separated into a video signal and an audio signal, and when the vehicle speed is below a certain speed and the vehicle is stopped, both the video signal and the high-pitched audio signal are sent to the TV.
Also, when the vehicle speed is above a certain speed, only the audio signal is output from the TV.

In such a car display device, the reception condition of radio waves changes depending on the driving condition of the vehicle, so deterioration of image quality becomes a problem.

For this reason, conventionally, such automotive TV apparatuses have adopted a diversity reception system in which a plurality of TV antennas are installed and the optimum TV antenna is selected and used depending on the receiving condition of broadcasting radio waves.

As such a system, there is a well-known car TV diversity receiving device in which a plurality of TV antennas are installed in advance in various parts of the car body, and the optimum TV antenna is selected and used based on the reception status of the video signal separated from the received signal. be.

This device performs a selection switching operation in which the video signal level is compared with a reference level and the optimal TV antenna is selected in synchronization with the vertical blanking period of the video signal.

As such a conventional antenna device, it has been proposed to detect surface current induced in the vehicle body itself by broadcast waves.

However, although using the electric current flowing through the car body seems at first glance to be the most reliable and efficient method, conventional experiments have continued to show results that completely contradict these expectations.

In other words, the first reason why it was not possible to use the surface current generated by general car body broadcast waves is that the surface current value is not as large as expected, and the conventional surface current mainly targets the car body ceiling panel. However, even with this, it was not possible to obtain a level of detection output sufficient for full use.

The second reason is that a large proportion of noise is mixed into the surface current, and such noise is mainly generated from the engine's ignition system and battery charging regulator system. As long as the engine was active, these noises leaked into the vehicle body, making it impossible to receive clear broadcast wave reception on the side of the vehicle.

[Problems to be Solved by the Invention] Problems with the Prior Art As mentioned above, in the past, TV antennas for detecting the current induced in the vehicle body by broadcast waves have not always been successful.

The problem here is that the pickup structure to effectively detect the current induced by the broadcast waves flowing through the car body and the pickup placement to obtain a practical S/N ratio have not been properly resolved. That's true. In particular, the high-frequency directivity characteristics of high-frequency pickups used as antennas are poor, and F
There is a problem in that multipath noise tends to occur when receiving M broadcasts.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to effectively detect the current induced in the vehicle body by broadcast waves using a diversity reception system, and to improve the effectiveness of the vehicle-mounted TV receiver. An object of the present invention is to provide an improved automatic heavy-duty TV antenna device capable of transmitting information.

[Means and operations for solving the problems] In order to achieve the above object, the present invention provides a plurality of high-frequency surface currents that are induced in the vehicle body by broadcast waves and flow concentrated at the periphery of the vehicle body. It is equipped with several high-frequency pickups, and can automatically select and switch the high-frequency pickup with a good reception condition among these high-frequency pickups.

In order to improve the directivity characteristics of the high-frequency pickup as an antenna, a ceiling high-frequency pickup and a trunk hinge high-frequency pickup are provided to compensate for the weak sensitivity characteristics of each other.

That is, the ceiling high frequency pickup is fixed separately to either the vehicle body ceiling peripheral plate, for example, the rear side frame of the vehicle body or the header inner panel. The longitudinal length of this retainer is such that the surface current flowing through the periphery of the vehicle body is likely to resonate for frequencies of 50 MH2 or more, that is, the length is approximately equal to the wavelength of the television band.

Further, in order to increase the centrality of the current, the retainer is disposed approximately 2×10−3× wavelength apart from the rear window frame or header inner panel, which serves as a peripheral plate of the vehicle ceiling through which surface current flows. .

The loop antenna of the ceiling high frequency pickup is arranged close to the edge molding retainer along the longitudinal direction.

On the other hand, the trunk hinge high frequency pickup is arranged close to the trunk hinge along the longitudinal direction.

According to the above configuration, in the characteristics of picking up the high frequency surface current induced in the car body by broadcast waves, that is, the directional characteristics as an antenna, the direction of weak sensitivity of both the ceiling high frequency pickup and the trunk hinge high frequency pickup is suppressed. They can complement each other, and by providing a plurality of ceiling high frequency pickups and a plurality of trunk hinge high frequency pickups, reception sensitivity can be increased, and diversity reception with good sensitivity characteristics and good directivity characteristics can be realized.

[Example] Preferred embodiments of the present invention will be described below based on the drawings.

Characteristics of high frequency current in the vehicle body Figures 11 to 16 are explanatory diagrams for determining the most efficient antenna installation position by examining the distribution characteristics of high frequency current.

Figure 11 shows that when an external radio wave W such as a broadcast wave passes through a car body B made of gold IS, a surface current (■) corresponding to the strength of the electromagnetic wave is induced in each part of the body (■). In the present invention, only the frequency bands used for FM waves, television waves, etc. of 50 HI [z or higher, which belong to relatively high frequency bands among these radio waves, are targeted.

In the present invention, the induced current distribution of the vehicle body is measured in such a specific high frequency band, and the pickup is placed in a part where the surface current density is high and there is little noise.
It is characterized by a.

In order to know the surface current distribution, simulations are performed by calculation and the actual current intensity is measured at each point.In the present invention, a probe based on the same principle as a high frequency pickup installed in a desired vehicle body part, which will be described later, is used. was used, and the surface current was measured by moving the probe over the entire surface of the vehicle, changing direction at each point.

FIG. 12 shows a schematic configuration of a probe P created based on almost the same principle as a high frequency pickup described later, and a case 10 made of an electric shock body is shown in FIG. Loop coil 1 inside
2 is fixed, and a part of the case 10 has a frontage 10aI.
fi is provided, and a part of the loop coil 12 is connected to this frontage 10.
A is exposed to the outside, and the exposed portion of the loop coil 12 is brought close to the surface of the vehicle body B so that the loop coil 12 detects the magnetic flux generated from the vehicle body surface current.

A part of the loop coil 12 is connected to case 1 by a shorting wire 14.
0, and the output end 16 is connected to the coaxial cable 1.
8 core wires 20. Also, the loop coil 12
A capacitor 22h is provided in a part of the loop coil 12 to resonate the frequency of the loop coil 12 to the desired frequency to be measured, thereby increasing the pickup efficiency.

As described above, by moving the probe P along the surface of the vehicle body B and rotating its angle at each measurement point, it is possible to accurately determine the surface current distribution and its direction on the vehicle body surface. In FIG. 12, the output of the probe P is amplified by a high frequency voltage amplifier 24, and the output voltage is measured by a high frequency voltage measuring device 26. This coil output voltage is read by the meter indication value of the measuring device 26, and the voltage corresponding to this meter indication value is recorded by the XY recorder 28 as a surface current distribution in each part of the vehicle body. The XY recorder 28 has a potentiometer 3
A signal indicating each position of the vehicle body is input from 0 to 0, making it possible to know the high frequency surface current at each position.

FIG. 13 shows the declination angle θ between the pick-up loop coil 12 of the high-frequency surface current device 110, and as shown in the figure, the magnetic flux φ due to the current 1 is caused by interlinking with the loop coil 12. A detection voltage V is generated in the loop coil 12, and as shown in FIG. By rotating the probe P, it is possible to know the direction of the surface current I when the maximum voltage is obtained.

Figures 15 and 16 show the magnitude and direction of the high-frequency surface current generated in each part of the car body at the frequency of 808IIZ, which was determined from both the measurement results with the probe P mentioned above and the computer simulation 1. ,
As is clear from FIG. 15, the magnitude of the surface current exhibits a distribution in which the density is high along the edges of the flat portion of the vehicle body, and the density is extremely low in the central portion of the flat portion of the vehicle body.

Furthermore, as shown in the direction of the current in FIG. 16, it is understood that each current is concentrated in a direction parallel to the edge of the vehicle body or along a connecting portion of each plane portion.

The characteristic feature of the present invention is that a plurality of high-frequency pickups are installed to effectively pick up the high-frequency surface current induced in the vehicle body using a diversity method, and at this time, the directional characteristics of the antenna are improved. For this purpose, a ceiling high-frequency pickup and a trunk hinge high-frequency pickup are provided. here,
Although a plurality of these mountain bird frequency pickups are provided, in this embodiment, a ceiling high frequency pickup and a trunk hinge high frequency pickup are provided in pairs on the left and right sides. In this case, the ceiling high frequency pickup may be provided on the front window side or may be provided on the rear window side.

Ceiling High Frequency Pickup FIG. 1 shows two ceiling high frequency pickups 31-1.32-2 and two trunk hinge high frequency pickups 34-1.34-2, which constitute a diversity antenna.
The ceiling high frequency pickup may be placed on the 7[] window side like a ceiling high frequency pickup 32--1.32''-2.

Further, FIG. 2 shows a state in which the ceiling high-frequency pickup 32 is disposed on the rear window side, and FIG. 3 shows a cross section of the ceiling high-frequency pickup 32.

In FIG. 2, the ceiling plate 36 is shown in an exposed state, and is connected to the rear glass 40 via a beam 7 and a window frame 38.

In the embodiment, as described above, the ceiling high frequency pickups 32-1, 32-2 are placed on the right and left sides of the edge molding retainer 42. This ceiling high frequency pickup 32, as shown in FIG.
It has a metal case 44 that shields magnetic flux from the outside, and includes a loop antenna 46 inside to form an electromagnetic coupling type pickup, similar to the probe including the loop coil using the surface current distribution of the vehicle body described above. Structure))S
Consisting of

In the figure, the ceiling plate 48 includes a roof panel 50, and the rear window frame 52 is connected to the roof panel 50.
Further, the rear glass 40 is fixed to the roof panel 50 via a fastener 53 and a dam 54, and the fastener 53 and the dam 54 are airtightly attached with an adhesive 56. In this case, there is a molding 58 between the roof panel 50 and the rear glass 40.
is fixed.

A roof garnish 60 is fixed to the roof panel 50 on the inside of the rear window frame 52 (on the inside of the vehicle body) in the ceiling plate 48, and a side pant between the roof garnish 60 and the rear window frame 52 has a Edgemol 62 is fixed. A retainer 42 for attaching the edge molding 62 is disposed between the rear window frame 52 and the roof garnish 60.

This retainer 42 is separated from the rear window frame 52 by spacers 64-1 and 64-2, and is designed to facilitate concentration of surface current.

That is, the change in antenna sensitivity with respect to the distance between the rear window frame 52 and the retainer 42, that is, the change in surface current density, is shown in FIG. 4, and as is clear from this figure, the antenna sensitivity is approximately 2×10 − The maximum value is reached at 3× wavelength. Therefore, by separating the retainer 42 from the rear window frame 52 by the above-mentioned length, it is possible to increase the degree of concentration of the current flowing to the peripheral portion of the vehicle body.

In this embodiment, since the loop antenna 46 of the ceiling high frequency pickup 32 is disposed opposite to the peripheral part of the edge molding retainer 42, the rear window frame 52 is first provided with an opening 52a at one end thereof. A case 44 of the ceiling high frequency pickup 32 is inserted into this opening 52a. In this way, the ceiling high-frequency pickup 32 can pick up the surface Ti flow induced on the vehicle body, but as described above, the retainer 42 is connected to the rear window frame 52.
In particular, the longitudinal length of the retainer 42 is approximately half a wavelength for the LO band of TV transmission, approximately one wavelength for the Hi band, and approximately 1 wavelength for the UHF band. Since the length is approximately 2 to 4 wavelengths, it becomes easier to concentrate in these bands, allowing highly sensitive reception.

Note that a circuit section 47 including a preamplifier and the like is connected to the loop antenna 46.

Furthermore, the ceiling high frequency pickup 32 can also be placed on the front window side, and as shown in FIG.
2 is shown in cross section with the roof plate 48 disposed on the entire vehicle body.

The ceiling high frequency pickup 32- is provided near the peripheral edge of the ceiling plate 48 on the front window side, and is disposed within the service hole 66a of the header inner panel 66.

A windshield 140 is fixed to the roof panel 50 of the ceiling board 48 via a dam 154, and a molding 158 connects the roof panel 50 and the windshield 140.
connecting between. Similarly to the ceiling high frequency pickup 32 on the rear window side, the Edge Mall 16
For attaching the retainer 14 for attaching 2
2 is arranged between the header inner panel 66 and the roof garnish 60.

The edge molding retainer 142 is separated from the header inner panel 66 by subenaces 164 to 1.164-2, and is designed to facilitate concentration of surface current.

Therefore, the magnetic flux induced from the high-frequency surface current flowing to the periphery of the header inner panel 66 inside the case 44 is reliably supplemented by the loop antenna 46, and the electromagnetic waves from the outside are reliably shielded by the case 44. The current induced in the vehicle body can be detected with high sensitivity by the ceiling frequency pickup 32'.

In the embodiment, the portion of the loop antenna 46 exposed from the case 44 extends from the edge of the retainer 42° 142.
．． placed within 5 cm, thereby 50HIIZ
As described above, it is possible to detect the car body surface current induced and flowing in the peripheral part of the retainer 42, 142 by broadcast waves having a frequency in the FM band or TV band in particular, and the direction of the car body surface current at this time can be determined from Fig. 16. As is clear, since the flow is along the peripheral edge of the loop antenna 46, in the embodiment, the longitudinal direction of the loop antenna 46 is aligned with the retainer 42.
, 142.

Trunk hinge high frequency pickup In the present invention, a trunk hinge high frequency pickup is provided to supplement the directional characteristics of the ceiling high frequency pickup 32 as an antenna, and this trunk hinge has a high frequency pickup as shown in FIG. , a high-density surface current that is equal to or higher than the squared part flows, and this tendency becomes more pronounced as the frequency increases, making it possible to detect current from the trunk hinge, which was almost unthinkable in the conventional AM band. do.

Also, the trunk hinge is far away from the engine.
It is less susceptible to noise from the vehicle body and has the advantage of being able to obtain high-quality current detection values with an excellent S/N ratio.

FIG. 6 shows how the trunk hinge high frequency pickup is installed, and FIG. 7 shows its detailed structure. In this embodiment, the trunk hinge high frequency pickup 34 is an electromagnetic coupling type pickup, and like the ceiling high frequency pickup 32, it has a structure including a loop antenna 44 for detecting the surface current distribution of the vehicle body.

In the figure, one end of the trunk hinge 68 is pivotally supported by the main body, and the other end is fixed to the trunk lid 70.
It forms a rotating wheel branch of the trunk lid 70. Additionally, a torsion bar 72 is provided on the shaft support side of the trunk hinge 68.
is provided to perform a positioning function when the trunk lid 70 is opened. As is well known, trunk lid 7
A watertight weather strip 74 is provided between the rear window 40 and the vehicle body to prevent rainwater from entering through the rear window 40.

In the embodiment, the trunk hinge high frequency pickup 3
4 is fixed on the outside along the longitudinal direction of the trunk hinge 68, that is, on the trunk room side, and the loop antenna 76 provided inside is arranged so that its longitudinal direction coincides with the longitudinal direction of the trunk hinge 68. is,
In the present invention, the surface current flowing through the trunk hinge 34 can be reliably captured by the loop antenna 76 with high efficiency.

Like the ceiling high-frequency pickup 32, the trunk hinge high-frequency pickup 34 includes a case 78 made of a conductive material, and a loop antenna 76, a circuit section 47 including a preamplifier, etc. are built in the case 78, and the opening side thereof is connected to the trunk. They face the hinge 68. and,
Fittings 80-1.80 are installed at both ends of the opening of the case 78.
-2 is firmly fixed with screws. Therefore,
Only the magnetic flux induced from the high-frequency surface current flowing through the trunk hinge 68 is captured inside the case 78, and the magnetic flux from the outside is reliably shielded by the case 78.

Here, the loop antenna 76 is connected to the trunk hinge 68.
It is preferable that the trunk hinge 68 be provided along the curvature of the trunk hinge 68 and have a shape that matches the curvature of the trunk hinge 68.

The circuit section 47 is supplied with power and signals for controlling the circuit from a cable 82, and is also supplied with a loop antenna 76.
The high frequency detection signal extracted by the coaxial cable 84
and processed by a circuit similar to that used in the surface current distribution described above.

The loop antenna 76 is made of a single-turn antenna, and has a structure in which an insulating coating is applied to the coil so that it is placed in close contact with the trunk hinge 68 while being electrically insulated, and the coil is pressed against the trunk hinge 68. , the magnetic flux generated from the surface current can be efficiently linked to the loop antenna.

As mentioned above, the trunk hinge high frequency pickup can be placed on the back side of the 1 to rank hinges 68 instead of on the front side. This can prevent damage or damage.

In this way, according to the embodiment, it is possible to detect a surface current from the trunk hinge that is somewhat different from the detected value of the vehicle body surface current, and the surface current can be used as an antenna for both the ceiling high frequency pickup 32 and the trunk 228 frequency pickup 34. Broadcast waves can be received with good directional characteristics that combine the directional characteristics of .

Receiving Broadcast Waves Next, FIG. 8 shows a circuit configuration for receiving broadcast waves, including a ceiling high-frequency pickup 32-1, 32-2, and a trunk hinge high-frequency pickup 34-1, 34-.
2, each received signal is transmitted through coaxial cables 86-1 to 86.
-4 is input to the switching circuit 88.

This switching circuit 88 switches between the ceiling high-frequency pickup 32 and the trunk hinge high-frequency pickup 34 used for receiving TV broadcast radio waves, and switches the received signal from any one of these pickups. The selected signal is output to the tuner 90.

This tuner 90 performs tuning of the received signal, and is comprised of well-known circuits such as a high frequency amplifier 921, a local oscillator 94, and a mixer 96. Then, the received signal tuned by the tuner 90 is transmitted to the video intermediate frequency amplifier 9.
8 and output to the image display circuit 100 and the audio output circuit 102, respectively.

Here, the output of the audio output circuit 102 is supplied to a speaker 104, and audio is output from the speaker 104.

The image display circuit 100 of this embodiment also includes a drive state determination circuit 106 that determines whether the vehicle is stopped or running, and a switch 110 that is provided between the video detection circuit 108 and the video amplifier 112 and that turns on and off the detection signal. The switch 110 is turned on when the drive state determination circuit 106 detects that the vehicle is stopped, and the switch 110 is turned off when the drive state determination circuit 106 detects that the vehicle is running.

As shown in FIG. 9, the circuit configuration of the drive state determination circuit 106 determines whether the vehicle is stopped when both the parking switch and the handbrake are turned on and the vehicle speed falls below a certain reference speed. are doing. Then, a high level signal is output from the AND gate,
This turns on the switch 110, and in cases other than the above conditions, it is determined that the vehicle is in a running state, and a low level signal is output from the AND gate to turn off the switch 110. In this case, the vehicle speed detection section inputs a vehicle speed detection pulse to a comparator via a bypass filter, and the detection is performed by comparing this pulse with a predetermined reference value.

Therefore, in the embodiment device, when the vehicle is stopped,
Since the switch 110 is turned on, an image is displayed on the cathode ray tube 118 and audio is output from the video speaker 104. Furthermore, since the switch 110 is turned off when the vehicle is running, no image is displayed on the cathode ray tube 118, and only audio from the video speaker 104 is output.

In this way, when the vehicle is running, only audio is output from the speaker 104, thereby preventing the driver's attentiveness from decreasing which would be caused by displaying images while the vehicle is running.

In the present invention, while the vehicle is running, the ceiling high frequency signal used for reception follows changes in the reception condition of TV broadcasting radio waves and provides good images and sound every 1 quarter. A diversity reception system is implemented to optimally switch the pickup 32 and the trunk hinge high frequency pickup 34.

In other words, the switching circuit 88 that switches the antenna is the antenna switching circuit 1 that generates the switching signal 120a when the output of the video detection circuit 108 falls below a specific level.
20, there is a movement to switch to the antenna with the best reception condition.

Note that antenna switching can also be performed using audio detection output.

Also, the antenna switching timing is determined by the vertical synchronization signal 116.
A can be set to II and switched in the retrace section of the scanning line.

In this way, the radio waves for TV broadcasting are always received in good condition by selecting the high frequency pickup with the best reception condition.However, in the present invention, the high frequency pickup installed in the ceiling and trunk hinge To make the directional characteristics of antennas mutually complementary and good.

Fig. 10 shows the antenna directivity characteristics in the TV band, Fig. 10(a) shows the characteristics of the ceiling high frequency pickup 32 installed on the rear window frame side, and Fig. 10(b) shows the antenna directivity characteristics in the TV band. The characteristics of the hinge section high frequency pickup 34 are shown.

As is clear from the figure, the ceiling high frequency pickup 32
The characteristic curve 200 of the trunk hinge section high frequency pickup 34 shows a highly sensitive characteristic in the left and right directions of the vehicle, and the characteristic curve 300 of the trunk hinge high frequency pickup 34 shows a highly sensitive characteristic in the front and rear of the vehicle.
If diversity reception is performed based on a plurality of high frequency pickups having both of these characteristics, it is possible to compensate for each other's low sensitivity in the direction (2), and the best TV reception condition can be achieved.

In the above embodiments, an electromagnetic coupling type is used as the trunk hinge high frequency pickup 34, but an electrostatic coupling type high frequency pickup may also be used. In the case of this capacitive coupling type, a detection electrode is arranged along the longitudinal direction of the first to rank hinges 68 via an air layer or an insulating plate, and a static electricity is formed between the surface of the trunk hinge 68 and the detection electrode. It is possible to extract high frequency surface current via capacitance.

[Effects of the Invention] As explained above, according to the present invention, the diversity reception antenna is configured by the ceiling high-frequency pickup and the trunk hinge high-frequency pickup, which have different directional characteristics, so that the directional characteristics of the antenna are significantly improved. Moreover, it is possible to receive broadcasting radio waves with reduced multipath noise.

Furthermore, since broadcast waves can be received from high-frequency surface currents induced in the vehicle body, there is an advantage that there is no need to provide a plurality of externally protruding antennas.

[Brief explanation of drawings]

Figure 1 is an overall view showing the arrangement positions of the ceiling high-frequency pickup and the trunk hinge high-frequency pickup in the present invention, and Figure 2 shows the ceiling high-frequency pickup constituting the diversity antenna attached to the ceiling plate on the rear window side. Figure 3 is a cross-sectional view of Figure 2. Figure 4 is an explanatory diagram showing changes in antenna sensitivity with respect to the distance between the rear wind frame and the retainer. FIG. 6 is an explanatory diagram showing the trunk hinge high-frequency pickup in a fixed state; FIG. 7 is a cross-sectional view of the trunk hinge high-frequency pickup; FIG. 8 is the device of the present invention. 9 is a detailed diagram of the drive state determination circuit in FIG. 6, and FIG. 10 is a diagram showing the antenna directional characteristics in the TV band. (a) is the directional characteristic of the ceiling high frequency pickup;
(b) is an explanatory diagram showing the directivity characteristics of the trunk hinge high-frequency pickup, FIG. 11 is an explanatory diagram showing the surface electric current created on the vehicle body B by the external wave W, and FIG. 12 is similar to the high-frequency pickup used in the present invention. An explanatory diagram of a probe and its processing circuit for determining the distribution of surface current of a heavy body using a probe of FIG. 15 is an explanatory diagram showing the directivity characteristics of the loop antenna in FIG. 12, FIG. 15 is an explanatory diagram showing the distribution characteristics of surface current intensity, and FIG. 16 is an explanatory diagram showing the direction of surface current. 32 ... Ceiling high frequency pickup 34 ...
Trunk hinge high frequency pickup 40...
Rear glass 42.142 ・・・ Retainer 46.76 ・・・ Loop antenna 48 ・・・ Edge mall installation
Ceiling board 52... Rear window frame 66... Header inner panel.

Claims (5)

[Claims] (1) In an automotive TV antenna device that is equipped with a plurality of high-frequency pickups that effectively pick up high-frequency surface currents that are induced in the car body by broadcast waves and flows concentrated around the periphery of the car body, and that automatically selects these high-frequency pickups. , approximately 2 x 10^-^3 x from the car body ceiling peripheral plate through which the surface current flows in order to increase the concentration of current, and to increase the concentration of current. A retainer for attaching to an edge molding that is separated by a wavelength, a high-frequency pickup on the ceiling with a loop antenna placed close to the retainer for attaching to an edge molding along the longitudinal direction of the retainer for attaching to the edge molding, and a trunk that is arranged along the longitudinal direction of the trunk hinge. An automobile TV characterized by being provided with a hinge section high frequency pickup.
antenna device. (2) In the device according to claim (1), the ceiling high frequency pickup is located at a position near the rear window side periphery of the rear window frame at the rear of the vehicle body or at a position near the windshield side periphery of the header inner panel at the front of the vehicle body. A TV antenna device for an automobile, characterized in that it is disposed in any one of the following. (3) In the device according to claim (1), the trunk hinge high-frequency pickup includes a loop antenna fixed along the trunk hinge, and the high-frequency pickup includes a loop antenna fixed along the trunk hinge, and the magnetic field formed by the high-frequency surface current flowing in the trunk hinge is transmitted to the trunk hinge. An automotive TV antenna device characterized by electromagnetic detection using a loop antenna. (4) In the device according to claim (1), the trunk hinge high-frequency pickup has a detection electrode arranged close to the trunk hinge, and generates a high-frequency surface current by capacitive coupling between the trunk hinge and the detection electrode. An automotive antenna TV device characterized by detecting. (5) Claims (1), (2), (3), (4)
A TV antenna device for an automobile as described above, characterized in that a pair of the ceiling high frequency pickup and the trunk hinge high frequency pickup are provided on each side of the vehicle body.