JPH061847B2 - Car antenna device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to an antenna device for an automobile, and more particularly to a device for improving reception of TV broadcast radio waves.

[Conventional technology]

2. Description of the Related Art Conventionally, it is known that a rear window glass of a vehicle (inside the vehicle) is provided with a plurality of heater wires for preventing fog and an antenna wire for radio reception. This antenna line is generally tuned so as to obtain a good reception output in the AM and FM bands, and cannot receive TV broadcast waves. Therefore, in order to receive radio broadcasts and TV broadcasts in the car, a dedicated antenna for TV must be attached.

However, it is generally difficult to attach a wideband Yagi-Uda antenna exclusively used for TV reception to a passenger car or the like. Therefore, a TV antenna wire is attached to the vehicle body surface like an AM / FM window glass antenna. You have to think about attaching it. However, most of the body of the automobile is an iron plate, and the rear window glass is occupied by the heater wire and the antenna wire for radio. Since most of the side window glass of a passenger car is a slide glass that can be opened, an antenna wire cannot be attached. Further, it is not preferable in view to attach an antenna wire to the windshield.

Furthermore, even if a TV antenna wire can be attached, the domestic TV broadcasting frequency is in the low band (90 to 1 of the first to third channels).
08MHz) to high band (4th to 12th channel 1)
70 to 222 MHz), it is very difficult to cover all these bands with one antenna line.

[Problems to be solved by the invention]

In view of the above problems, it is an object of the present invention to effectively utilize a limited antenna installation location and to enable good reception in a TV broadcast band.

[Means for solving problems]

The antenna device for an automobile of the present invention is a radio antenna 1 attached to the surface of a rear window glass 10 of the automobile, TV antennas 7 and 8 attached to the rear quarter of the automobile capable of receiving TV broadcast waves. A diversity receiver (diversity controller 9) for deriving a diversity reception output to the TV tuner 5 by using the TV low band reception output of the radio antenna 1 and the reception outputs of the TV antennas 7 and 8 as inputs, and the radio antenna The changeover switch 2 for selectively supplying the reception output of No. 1 to the radio tuner 4 and the diversity receiving device on the TV side;
Alternatively, there is provided control means for switching the changeover switch 2 to the operation tuner side when the operation of the radio tuner is turned on.

With this configuration, good TV broadcast reception is possible even if the location of the antenna is extremely limited.

〔Example〕

FIG. 1 is a system diagram of an antenna device for a vehicle according to the present invention. With respect to TV radio waves, a plurality of antenna lines are used and diversity reception is performed according to the respective received electric field strengths. In FIG. 1, a reception output of a glass antenna wire 1 attached to a rear window glass of an automobile is led to a radio tuner 4 from a changeover switch 2 through a filter 3.
The filter 3 is inserted in order to allow the reception output of the rear window glass antenna wire 1 to pass the upper limit of 90 MHz or less in the FM band and reduce interference with radio reception by TV radio waves.

The rear window glass antenna wire 1 is a low band (first
~ ~ Third channel) is also used. That is, the low band of TV is adjacent to the FM band, and if limited to this low band, a good reception output can be obtained from the AM / FM antenna line 1. If the rear window glass antenna wire 1 is incorporated into the TV diversity receiving system, the function of the other TV antenna wires for diversity can be increased to a high band (4th
~ 12th channel), the design of the antenna line where the installation location is limited becomes easy, and extremely high-sensitivity reception becomes possible as a whole system.

In FIG. 1, when the TV tuner 5 is turned on, the changeover switch 2 is turned on by the control output from this tuner.
And the output of the rear window antenna 1 is led to the switch 6. The switch 6 includes a rear quarter antenna 7 (right) and a rear quarter antenna 8. The reception output of (left) is also supplied. Switch 6
The one reception output selected in 1 is led to the diversity controller 9, where the switching control signal is formed so that the reception intensity is maximized. Therefore, the best one of the plurality of TV reception outputs is always selected and output from the switch 6 and led to the TV tuner 5 through the diversity controller 5.

As the rear window glass antenna wire 1, the one as shown in FIG. 2 can be used as an example. Inside the rear window glass 10 shown in FIG. 2, a plurality of anti-fog heater wires 11 are attached, and a heating current is supplied through the mother ships 12 and 13. The antenna wire 1 is provided with a dipole-like element 1a extending in parallel with the heater wire 11, and a feeding point 14 is provided from substantially the center thereof.
The received output is derived at. In order to enhance the reception output of the medium wave (AM), one end of the element 1a is connected to almost the center of the upper stage of the heater wire 11 via the folded portion 1b.

On the other hand, the above-described rear quarter antennas 7 and 8 are, for example, those in which the antennas are attached to the resin decorative plates 15 and 16 on both side surfaces connected to the rear surface of the automobile shown in FIG. Fourth
A and FIG. 4B are back views of the decorative plates 16 (left side) and 15 (right side), and the antenna element 17 is attached to each by welding, pasting, metal plating, printing or the like. The antenna wire may be embedded when the decorative board is molded. Each antenna element 17 has a shape in which an L-shaped contour is surrounded by an antenna wire, and includes a vertical element 17a and a horizontal element 17b that form an L-shape, and is arranged in a high band (fourth
~ Channel 12) is tuned. The reception output is led to the feeding point 18 from the vicinity of the L-shaped corner.

FIG. 5 is a horizontal cross section of the decorative plate 15. The decorative plate 15 is attached to the body 19 (iron plate) of the automobile through a gap 20. Therefore, the antenna element 17 is attached to the body 19 so as to be separated from the body 19 through the air layer, so that the capacitive coupling to the body is small. In this way, the body 1 is provided on the back side of the decorative plate 15 (or 16).
Since there is 9 (iron plate), the feeding point 18 is a decorative plate 15, 16
Can be provided at any position within the plane of the. In other words, the degree of freedom in designing the signal derivation position is large, and it is highly adaptable to changes in vehicle type. In the case of the window glass antenna as shown in FIG. 2, the position of the feeding point 14 is limited to both sides or the upper end of the window glass.

Further, since the iron plate body 19 is provided on the back side of the decorative plates 15 and 16, the antenna element 17 receives no radio wave from the direction of arrow A in FIG. Therefore, as shown in the antenna directional characteristic diagram of FIG. 6, the respective rear quarter antennas 7 and 8 have sharp directivities facing both sides at right angles to the traveling direction of the automobile.

Further, as shown in FIGS. 4A and 4B, the horizontal elements 17b of each antenna element 17 are arranged in line symmetry so as to be opposite to each other along the traveling direction of the automobile. That is, the horizontal element 17b on the right side of the decorative plate 15 faces rearward, and the horizontal element 17b on the left side of the decorative plate 16 faces 17b. The axis of symmetry in this case is a vertical line passing through the intermediate position between the left and right decorative plates 15 and 16 attached to the automobile. With this configuration, the directional characteristic has components directed to the front and the rear, respectively, as shown in FIG. Therefore, the two rear quarter antennas 7 and 8 can cover all the front, rear, left and right directions, and when incorporated in a diversity receiving system, omnidirectional and very good receiving characteristics can be obtained.

FIG. 7 shows a modification of the glass antenna, in which the high band side output of TV radio waves is also taken out from the rear window glass antenna wire 21 for AM / FM reception and used for diversity reception.
The overall characteristics of TV reception are further improved. The antenna wire 1 in the example of FIG. 7 is a Y-shaped main element 2
A bending element 21b is attached to one open end of 1a, and an auxiliary element 21c closely facing the heater wire 11 is provided at a substantially central position of the bending element 21b. This is intended to enhance (especially AM). Further, in order to tune the FM band, an auxiliary element 21b adjacent to the upper element of the main element 21a is provided. The reception output of AM / FM is derived from the feeding point 14.

By providing the feeding point 22 on the auxiliary element 21d, the TV reception output can be taken out. The auxiliary element 21d is a simple element for phase matching or impedance adjustment when viewed from the feeding point 14 on the radio side.
When viewed from the feeding point 22, the antenna length is half or less of the antenna length on the radio side, and particularly has a good TV reception characteristic for a high band of TV radio waves.

Thus, by adding another TV receiving feed point at an appropriate position of the antenna pattern originally tuned for AM / FM, this antenna pattern can be used also for TV. By incorporating this into a diversity system, the diversity effect can be further improved.

The TV reception output at the feeding point 22 in FIG. 7 is led to the switch 6 as shown in the block diagram of the main part of FIG. 8, and diversity reception is performed together with the other antenna outputs. Also in this case, the reception output obtained from the power feeding point 14 for the radio is transmitted to the TV.
It can be used for low band reception in the broadcast band.

As for the installation position of the TV antenna, if there is a window glass fitted and fixed in the rear quarter portion of a hard top type passenger car, a TV-dedicated antenna wire can be installed inside the window glass. In addition to the above TV antenna wire, a TV antenna wire may be attached to the windshield.

〔The invention's effect〕

As described above, the present invention uses the radio antenna wire attached to the rear window glass of an automobile also for low band reception of TV broadcast radio waves, and combines it with another TV dedicated antenna provided in the rear quarter section for diversity reception. In this way, the reception output of the radio antenna is automatically switched to the operation tuner side when the operation of the radio or TV tuner is turned on. Therefore, according to the present invention, not only is it advantageous in terms of installation space and manufacturing cost of the antenna by sharing the antenna between the radio and the TV, but also as a TV-only antenna, tuning is performed only for a high band of TV radio waves. Therefore, the desired reception characteristics can be relatively easily obtained even if the antenna installation location or installation area is limited. Even if the radio antenna is also used as a TV antenna, it is not necessary to make the band much wider, and it is easy to tune so that the TV low band adjacent to the FM broadcast band can be received.

Also, even if the radio antenna is shared between the radio and TV, the reception output can be automatically switched to the side of the operation tuner, so there is no need for complicated antenna switching operations. Since it operates as, the received power can be effectively used.

[Brief description of drawings]

FIG. 1 is a system diagram of an automobile antenna device according to the present invention, FIG. 2 is a pattern diagram of a heater wire and an antenna wire attached to a rear window glass, and FIG. 3 is a perspective view of a rear quarter portion of an automobile, FIG. 4A and FIG. FIG. 4B is a pattern diagram of a TV rear quarter antenna formed on a decorative plate of the rear quarter portion, FIG. 5 is a horizontal sectional view of a decorative plate mounting portion of an automobile, and FIG. 6 is a directional characteristic diagram of the rear quarter antenna. FIG. 7 is a pattern diagram showing a modified example of a radio antenna wire of a rear window glass, and FIG. 8 is a main part antenna system diagram in the case of FIG. In the reference numerals used in the drawings, 1 ……………… rear window glass antenna wire 2 ……………… change switch 4 ……………… radio tuner 5 ……………… TV tuner 6 …… ………… Switcher 7 ……………… Rear quarter antenna (right) 8 ……………… Rear quarter antenna (left) 9 ……………… Diversity controller 10 ……………… Rear window glass 11: Heater wire 14: Feeding point 15, 16: Decorative plate 17: Antenna element 18: Feeding point.

Claims (1)

[Claims] 1. A radio antenna attached to a surface of a rear window glass of an automobile, a TV antenna attached to a rear quarter of the automobile for receiving TV broadcast waves, and a low-band TV reception of the radio antenna. A diversity receiver that receives the output and the reception output of the TV antenna as input and derives the diversity reception output to the TV tuner, and the reception output of the radio antenna as a radio tuner and T
An antenna device for a vehicle, comprising: a changeover switch for selectively supplying to the V-side diversity receiving / transmitting device; and a control means for changing over the changeover switch to the operation tuner side when the TV or radio tuner is turned on.