JPH0349446Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to glass antennas, and in particular to a heating conductive wire that removes fogging that occurs on window glass.
It is suitable for use in glass antennas used as VHF band and UHF band antennas.

[Summary of the idea]

By attaching an auxiliary element with one end open in the heating area of the group of heating conductive wires for removing fogging generated on window glass, the heating conductive wires are tuned to a frequency in the receiving frequency band, This is a glass antenna with improved reception efficiency when a group of heating conductive wires is used as an antenna.

[Conventional technology]

Conventionally, AM radio or
A glass antenna with an antenna strip for receiving FM radio is known.

Such a glass antenna has the excellent advantage that it can be easily formed together with a heating conductive wire by printing and firing, and that tuning can be easily performed by selecting a conductor pattern.

By the way, recently, like television and car phones,
Many devices that use radio waves in the VHF and UHF bands are now being installed in automobiles. For this reason, it is conceivable to attach antennas for these devices on the rear window glass, but since conductive wires for heating are provided in most of the rear window glass, the blank space is not very wide. For this purpose, a new VHF band and
In many cases, it is not possible to secure space on the rear window glass to install a UHF band antenna.

Therefore, the heating conductive wire may be used as an antenna, so that the heating conductive wire has both an anti-fog function and an antenna function.

[Problem that the invention attempts to solve]

Conductive wires for heating are normally used only in the medium wave band, and should not be used in the VHF or UHF bands, because it is difficult to properly select the conductor pattern and tune it as an antenna. I couldn't do it.

Various proposals have been made in which an auxiliary conductor is extended from the heating conductive wire and coupled directly or capacitively to the antenna pattern above the conductor, thereby improving the reception characteristics and reception efficiency of the antenna pattern. (For example, patent application 1986-11275)
issue). However, since such an auxiliary conductor does not contribute anything to the function of the heating conductive wire as an antenna, it is still necessary to separately attach an antenna for the VHF and UHF bands.

In view of the above-mentioned problems, the present invention aims to enable efficient use of a group of heating conductive wires as an antenna for the VHF band or UHF band.

[Means for solving problems]

The glass antenna of the present invention consists of a plurality of heating conductive wires 20 attached to the surface of an automobile window glass.
and an auxiliary element 21 attached to the heating area 6 of the heating conductive wire group 2 and connected to the heating conductive wire 20 so that at least one end becomes an open end.

[Effect]

The open-ended auxiliary element 21 connected to the heating conductive wire group 20 changes the way the received waves ride on the heating conductive wire group 2. By attaching the auxiliary element 21 within the heating zone 6 of the heating conductive wire group 2 and setting the overall length C and the manner of attachment of this auxiliary element 21 in accordance with the target frequency band, the heating conductive wire Group 2 is tuned to the frequency of the receiving and transmitting frequency band.

〔Example〕

FIG. 1 is a front view and an electric circuit diagram of a glass antenna showing an embodiment of the present invention. As shown in FIG. 1, a heating conductive wire group 2 for preventing fogging is provided on the rear window glass 1 of an automobile, and these wires are heated by a battery 13 through busbars 7, 8, 9 and power supply lines 11, 12. A current is applied. An antenna wire group 4 is provided in the upper margin 3 of the heating conductive wire group 2 and is coupled to a feeding point 14 for receiving output and led out to a preamplifier 16 via a coaxial cable 15 . Preamplifier 16 supports AM wave band and
The received signal in the FM wave band is divided into each band and amplified before being sent to the tuner.

The heating conductive wire group 2 is also used, for example, as a VHF band antenna. The received signal is led out from bus bar 7 via coaxial cable 19 to preamplifier 16 .

In order to improve the reception efficiency of the heating conductive wire group 2, the feeder lines 11 and 12 between the heating conductive wire group 2, the battery 13, and the ground point (vehicle body) are provided with extremely high resistance in the radio frequency band. A high-frequency chiyoke coil 17 with a high frequency is inserted. Further, a decoupling capacitor 18 is coupled between the line and the ground point to prevent noise on the power line from being mixed into the received signal.

The heating conductive wire group 2, the bus bars 7, 8, 9, each antenna wire group 4, and the feeding point 14 are made of fine silver particles,
It is obtained by screen printing a conductive paste made by making a paste of low-melting point glass powder or the like with an organic solvent onto the window glass 1, and then firing it.

In order to improve the performance of the heating conductive wire group 2 as an antenna, a heating area 6 is provided as shown in FIG.
An auxiliary element 21 is provided inside. As shown in the enlarged view of FIG.
They are attached parallel to each other. The midpoint of this auxiliary element 21 and the heating conductive wire 20 are connected via a connecting wire 22. Therefore, the auxiliary element 21 is open at both ends.

The length c of the auxiliary element 21, the distance b between the auxiliary element 21 and the heating conductive wire 20, etc. are determined by tuning the heating conductive wire group 2 to a frequency in the VHF band. For example, when the spacing a of the heating conductive wires 20 is set to 30 mm, the spacing b is 5 mm, and the total length c of the auxiliary element 21 is 600 mm (the length d from the midpoint to the left and right open ends is 300 mm). ) as,
When receiving a frequency in the VHF band of 76-92MHz,
The antenna gain was significantly improved as shown in C of FIG. Note that FIG. 3A shows the gain of only the heating conductive wire group 2 without the auxiliary element 21, and FIG. 3B
As shown in the reference example in Fig. 4, an auxiliary element 23 with a length l = 400 mm is placed above the heating conductive wire group 2 at an interval t = 25.
This is the gain when one end is connected to the bus bar 9 by extending it horizontally with an opening of mm. In case B above, some increase in gain was observed, but heating conductive wire group 2
There is no tuning effect regarding the conductor distribution, and it is considered that the change in reception gain is simply due to the addition of the auxiliary element 23.

The auxiliary element 21 in the embodiment shown in FIG. 1 is characterized in that it is provided in the heating area 6 of the group of heating conductive wires 2, that is, in the area between the heating conductive wires 20 from the top to the bottom. This has the effect of changing the conductor distribution of the heating conductive wire group 2, adjusting the distribution of received waves riding on the conductive wire 20, and changing the effective length of the antenna as a result. Therefore, the heating conductive wire 2
It is necessary to optimally tune the pattern and dimensions of the auxiliary element 21 in the reception frequency band according to the length, interval, and number of zeros. In addition, in order to obtain the effect of changing the effective length of the antenna, it is preferable that the auxiliary element 21 be connected to the heating conductive wire 20 or the busbars 7, 8, and 9 directly or via the connecting wire 22, and that one end be left open. . Further, a plurality of auxiliary elements 21 may be used.

FIG. 5 shows another example of the auxiliary element 21, in which the auxiliary element 21 extends in parallel along the uppermost heating conductive wire 20, one end of which is directly connected to the bus bar 7, and the other end of the auxiliary element 21 extended in parallel. is left open. Even with this configuration, a desired tuning effect can be obtained for the group of heating conductive wires 2.

Note that the heating conductive wire group 2 may be of a both-side power supply type in which busbars are provided on both side edges of the rear window glass 1 and the heating current is passed only from one side to the other.

[Effect of idea]

As mentioned above, the present invention connects an auxiliary element with at least one open end to the heating area of a group of heating conductive wires for removing fog from the surface of automobile window glass. By changing the conductor distribution on the glass surface of the group of heating conductive wires, it is possible to tune well to frequencies in the VHF band or UHF band, for example. Therefore, the antenna efficiency of the heating conductive wire group can be improved without impairing the defogging function, and the heating conductive wire group can be effectively used as an antenna.

[Brief explanation of the drawing]

Fig. 1 is a front view and electrical circuit diagram of a rear window glass of an automobile showing an embodiment of the present invention, and Fig. 2 is an enlarged view showing details of the length and arrangement of the auxiliary elements shown in Fig. 1. Figure 3 shows a group of heating conductive wires.
A graph showing the reception sensitivity when used as a VHF band antenna, Figure 4 is a conductor pattern diagram of a group of heating conductive wires with auxiliary elements corresponding to characteristic B in Figure 3,
FIG. 5 is a front view and an electric circuit diagram similar to FIG. 1 showing another embodiment. In addition, in the symbols used in the drawings, 1... Rear window glass, 2... Heating conductive wire group, 4... Antenna wire group, 6... Heating area, 20... Heating conductive wire, 21... It is an auxiliary element.

Claims (1)

[Scope of utility model registration request] A plurality of heating conductive wires attached to the surface of an automobile window glass and a group of heating conductive wires attached within the heating area and connected to the heating conductive wire so that at least one end is an open end. A glass antenna comprising a auxiliary element.