JPH0134411Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass antenna for automobiles that can be optimally used in a diversity antenna system in which a plurality of antennas are switched as desired.

Glass antennas, in which antenna wires are provided on the surface or inside of the window glass of a car, are widely used as antennas for on-vehicle radio receivers of cars. Such glass antennas have excellent omnidirectionality, receiving sensitivity, and S/N ratio by improving the antenna wire pattern, improving the amplifier, chiyoke coil, capacitor, etc. attached to the antenna. For example, an antenna 23 with a feed point 22 on the side of a glass plate 21, a busbar 24, 24' that is divided into two upper and lower parts, and a plurality of heater wires, have an asymmetrical pattern as shown in Fig. 1. Electric heating heater 2 for fogging removal having 25
6 provided on the glass plate 21.
When receiving horizontally polarized radio waves in the FM broadcast band, there is little directivity in the horizontal plane.
It is used in automobiles as an antenna with excellent reception performance for broadcast waves.

However, even in such glass antennas, when receiving radio waves emitted from a transmitting antenna of a radio broadcasting station under certain conditions, sharp directivity often appears. For example, when receiving in a valley between buildings or in a place where the influence of reflected waves is large, omnidirectionality and sensitivity decrease.

In particular, ultra-short waves such as FM broadcast waves propagate in a straight line, so under certain conditions, the radio waves transmitted from the broadcasting station are not directly incident on the receiving antenna, but are In some cases, more signals reach the receiving antenna after being reflected by obstacles such as objects. It is thought that the plane of polarization of radio waves propagated through such a complicated path becomes twisted even if the plane of polarization that is transmitted is horizontal. In other words, it is thought that it will be biased towards the V component (vertical component).

However, from a practical point of view, the above-mentioned glass antenna is designed with a focus on horizontal polarization, which has the strongest effect on improving the omnidirectionality of FM broadcast waves. For example, the horizontally polarized wave component is weak,
For radio waves with a high vertical component, directivity appears and sensitivity decreases.

In order to improve reception performance when receiving radio waves with different polarization plane components, multiple antennas with different directivity are installed to improve reception performance when receiving radio waves with several polarization plane components. A diversity antenna system is known in which an antenna with superior sensitivity and directivity is selectively selected and used accordingly.

The present invention was devised as a result of studies with the aim of providing a glass antenna that is optimal for such a diversity antenna system and can thereby improve directivity. A first antenna is installed in the upper margin of the defogging current heating heater of a glass plate for a rear window of an automobile, which is equipped with a defogging current heating heater having a main heater wire and a bus bar for feeding power to the heater wire. , in a glass antenna for an automobile in which a second antenna is provided in the lower margin, the first
Either one of the above antenna and the second antenna has a left-right asymmetric antenna pattern with respect to the longitudinal center line of the vehicle, and the other has a left-right symmetric antenna pattern with respect to the same center line,
and a switching circuit is connected to the first antenna and the second antenna, so that a received signal from either the first antenna or the second antenna selected by the switching circuit is input to the radio receiver. The present invention relates to an improved automotive glass antenna characterized by the following.

According to the present invention, a glass plate having a comparatively wide margin at the top and bottom of the defogging current heating heater is used in a glass plate on which a defogging current heating heater is formed on a rear window glass plate of an automobile. hand,
It is possible to provide a glass antenna used in a diversity antenna system that has excellent omnidirectionality and high gain.

Hereinafter, the present invention will be explained in more detail with reference to the drawings.

In the figure, 1 is a glass plate for automobile windows, 2 is an energizing heater for defogging provided on this glass plate, and this energizing heater 2 for defogging is connected to a large number of heater wires 3 and the heater. It is composed of a bus bar 4 that supplies electricity to the line 3. Reference numeral 5 denotes a first antenna provided in the upper margin of the glass plate 1 where the energizing heater 2 for defogging is provided, and 6 is a first antenna provided at the lower part of the glass plate 1 where the energizing heater 2 for defogging is provided. This is a second antenna provided in the blank space.

The antenna conductors constituting the first antenna 5 and the second antenna 6, which are provided in the relatively wide margins at the top and bottom of the energizing heater 2 for removing fogging from the glass plate 1, are limited by wiring in large numbers. In order to effectively utilize the upper or lower blank space for improving antenna characteristics such as increasing gain and improving omnidirectionality, the horizontal antenna conductor is mainly used to extend in the horizontal direction within this blank space, that is, in the horizontal direction of the glass plate. It is preferable to do so.

The first antenna 5 and the second antenna 6 are designed to have different directivity characteristics so that they function as antennas that are selectively selected and used in the diversity antenna system. It is designed to complement the That is, in a portion where the directivity of either the first antenna or the second antenna is reduced and the gain is reduced, the other antenna is made to have a high gain, so that each antenna can prevent the performance of the other antenna from deteriorating. The patterns of the first and second antennas are designed to have complementary directivity characteristics, for example, patterns with characteristics such that dip points are shown in different directions.

In particular, the patterns of the first antenna 5 and the second antenna 6 in the present invention include a predetermined number of horizontal antenna conductors so that one of them is symmetrical with respect to the longitudinal center line of the vehicle. If necessary, the antenna pattern is symmetrical in combination with a vertical antenna conductor, and the other is asymmetrical with respect to the longitudinal center line of the vehicle.
A horizontally asymmetric antenna pattern is selected, which is a combination of a predetermined number of horizontal antenna conductors and, if necessary, a vertical antenna conductor.

In this way, one of the first and second antennas provided in the upper and lower margins of the electric heating heater for defogging a glass plate has a bilaterally symmetrical antenna pattern, and the other has a bilaterally asymmetrical antenna pattern. By forming a pattern, it becomes easy to make the directivity characteristics of each antenna different.

The specific patterns of the first antenna and the second antenna include the shape of the automobile, the dimensions and shape of the glass plate, the size and shape of the upper and lower margins of the electric heating heater for defogging the glass plate, etc. Accordingly, an appropriate pattern is selected so as to obtain the optimum gain and omnidirectionality as an antenna. The antenna conductors constituting the first and second antennas may be designed in a pattern that has high gain for both FM and AM broadcast waves and cooperates with both FM and AM broadcast waves. , and the antenna conductor
FM and AM are divided into a part that mainly receives AM broadcast waves and a part that mainly receives FM broadcast waves.
It may be designed to have a pattern that receives both broadcast waves, or it may be divided into a part that receives AM and FM broadcast waves and a part that mainly receives AM broadcast waves.
It may be designed to have a pattern that receives both FM and AM broadcast waves, or it may act as a reactance element or reactance element between the part that mainly receives FM broadcast waves and the part that receives AM broadcast waves. A conductive wire pattern is provided, and when receiving FM broadcasts, the part that receives AM broadcast waves is cut off.
The pattern is designed so that only the part that mainly receives FM broadcast waves works as an antenna, and when receiving AM broadcasts, both the part that receives AM broadcast waves and the part that mainly receives FM broadcast waves work as antennas. Good too.

Feed points 7 and 8 for connecting the antenna feeder lines of the first and second antennas 5 and 6
of the first and second antennas depending on their positions.
Since the directivity characteristics for FM broadcast waves change, depending on the desired directivity characteristics or considering the position on the installation wiring, set the center part of the top or bottom side of the glass plate 1, Alternatively, it may be provided on the upper or lower side, or on either the left or right side of the glass plate 1.

For example, as shown in Figures 3, 4, 9, 11, 15, and 17, the feed points 7 and 8 of both the first antenna 5 and the second antenna 6 may be provided at the center of the upper and lower sides of the glass plate. , 2nd, 5th, 8th, 10th, 14th, 1st
6 As shown in Figure 6, the first antenna 5 and the second antenna 6
Either one of the power feeding points 7 and 8 is provided at the center of the upper or lower side of the glass plate, and the other is provided at the side of the upper or lower side of the glass plate, or the sixth, twelfth,
As shown in Fig. 17, the feeding points 7 and 8 of the first antenna 5 and the second antenna 6 may be provided at the upper and lower parts of the same side of the glass plate, or alternatively, as shown in Figs. 7, 13, and 18. One of the feeding points 7 and 8 of the first antenna 5 and the second antenna 6 is provided at the upper or lower part of the right side of the glass plate, and the other one is provided at the upper or lower part of the left side of the glass plate.

Note that if the feeding points 7 and 8 of the first antenna 5 and the second antenna 6 are arranged on the same side of the glass plate 1,
Taking out the antenna feeder wire (by simplifying the structure, wiring work and installation work can be made easier, thereby reducing costs and also reducing the incidence of failure) Also, if the feeding points of the first and second antennas are arranged on opposite sides of the glass plate, the directivity characteristics of the first and second antennas can be made different so that they can be mutually controlled. In order to complement the directivity and improve omnidirectionality, it becomes easier to design the pattern of each antenna.

In addition, in the case of automobile antennas, the higher the ground clearance, the higher the gain can be obtained, and the more noise tends to be reduced. It is also possible to make the first antenna provided in the main antenna function as a main antenna, and the second antenna to function as a sub antenna. For example, the total length of the antenna conductors constituting the first antenna may be made longer than the total length of the antenna conductors constituting the second antenna, or the antenna occupation area of the first antenna may be made longer than the total length of the antenna conductors constituting the second antenna. The area occupied by the antenna may be larger than that of the antenna, so that the first antenna and the second antenna effectively function as selection antennas of a diversity antenna system.

As the left-right asymmetric antenna barn used for the first or second antenna,
The first antenna 5 shown in the figure, or the fifth, seventh,
The antenna pattern of the second antenna 6 shown in FIGS. 10 and 18 is recommended as a pattern that has excellent omnidirectionality for FM broadcast waves and a high gain for FM and AM broadcast waves. This antenna pattern has excellent omnidirectionality for FM broadcast waves, so it has the advantage of making it easy to design another antenna pattern to complement it.This antenna pattern is shown in Figures 19 and 20. Similarly, a main antenna line 30 having a feeding point 7 is provided near the side of the glass plate 1.
extending in the horizontal direction of the glass plate 1 near the upper window frame,
At the same time, an auxiliary antenna line 31 is provided at a predetermined interval from the main antenna line 30, and a phase adjustment antenna line 32 connecting the main antenna line 30 and the auxiliary antenna line 31 is further provided as a basic pattern. In addition, an additional antenna wire 33 is provided to improve the characteristics if necessary.

In the present invention, the first antenna 5 and the second antenna 6 provided in the upper and lower margins of the electrical heating heater 2 for defogging the glass plate 1 are as follows:
The first and second antennas may be provided at a distance of 2 cm or more from the defogging energizing heater 2 so that the first and second antennas are not adversely affected by the energizing heater 2 for defogging, such as generation of noise and reduction in gain. death,
Alternatively, use FM heating heater 2 for defogging.
The first antenna or
Alternatively, place either one of the second antennas close to the defogging current heating heater, for example, by 0.1 cm.
They may be spaced apart by ~1.0cm and not connected in terms of direct current, but connected in terms of high frequency.Alternatively, the first antenna or the second antenna may be Either one may be provided so as to be directly connected to a part of the defogging current-carrying heater 2. In addition, especially in the latter two cases, in order to prevent the high frequency current induced in the first or second antenna from flowing to the ground in at least one of the power supply lead wires of the energizing heater 2 for defogging. Or, in order to prevent the direct current of the battery, which causes noise, from flowing into the radio receiver side, a high frequency choke coil,
Alternatively, it is necessary to insert a capacitor and float the defogging energizing heater 2 using high frequency.

For example, the examples shown in Figs. 2 to 7 are glass antennas of the type in which the first and second antennas and the de-fogging energizing heater are placed 2 cm to 5 cm apart, and are shown in Figs. 14 to 18. In this example, one of the first and second antennas and the defrosting energizing heater are placed close to each other at a distance of 0.1 cm to 0.5 cm so that they are not connected in a direct current manner but are connected in a high frequency manner. It is a type of glass antenna installed with
The examples shown in FIGS. 8 to 13 are glass antennas in which one of the first and second antennas is directly connected to an energizing heater for defogging.

First and second glass antennas in the present invention
The antenna is provided within a single glass plate, but the directivity characteristics of the first and second antennas are determined by the difference in the position within the glass plate occupied by the first and second antennas, Also, various planes of polarization may be generated due to differences in the antenna pattern of the second antenna, differences in the position of the feeding point, and the influence of reflected waves from the car body, metal objects around windows, and energized heaters for defogging. The probability that they will be the same is extremely low considering the radio waves that we have.

In the present invention, as shown in each figure, the electric heating heaters 2 for defogging provided on the glass plate 1 are formed in parallel lines with a width of 0.5 mm at intervals of 2 cm to 4 cm in the lateral direction of the glass plate. The most common type is one having a large number of heater wires 3 of about 2 mm in diameter and a bus bar 4 connected to the heater wires for supplying current to the heater wires 3, but of course it is not limited to these. It's not a thing.

In addition, in the above-mentioned type of electricity heating heater 2 for defogging, in order to improve the omnidirectionality of the antenna, for example, the 3rd, 7th, 9th, 13th, 15th,
As shown in Figures 18 and 20, the pattern of the power supply circuit of the energizing heater 2 for defogging is U-shaped, that is, one of the opposing busbars 4 is divided into two vertically, and a lead wire 9 is connected to each of the busbars 4a and 4b. , 10 may be connected so that the supplied current flows from the bus bar 4a or 4b through the bus bar 4 to the bus bar 4b or 4a in a U-shape.

The antenna conductors constituting the first antenna and the second antenna in the present invention are made of a conductive paste made by mixing and suspending a conductive metal powder (for example, silver powder), a low melting point glass frit, a vehicle, and other desired components. The most typical type is the wire type, which is printed in a predetermined pattern on the surface of a glass plate, fired, and then plated if necessary, but conductive metal thin wires such as copper wire, tungsten wire, nichrome wire, etc. Of course it's fine. When using this thin metal wire, it is wired to a plastic interlayer film for laminated glass, and is sandwiched between two glass plates to form a laminated glass type.

In the above description of the present invention, two antennas, a first antenna and a second antenna, are installed in the upper and lower margins of an energized heater for defogging a glass plate for a rear window of an automobile.
This study was carried out on a glass antenna that was equipped with two antennas and selectively used the one with higher reception signal sensitivity among the two antennas. Install one or two more antennas in the blank space,
It is also possible to alternatively select and use the one of these antennas with a higher gain of the received signal.

When the glass antenna of the present invention is used in a diversity antenna system, one of a plurality of antenna outputs from a plurality of antennas, for example, two antenna outputs from a first antenna and a second antenna. A switching circuit for selectively selecting the antenna is provided between the feeding point of each constituent antenna of the glass antenna and the radio receiver, or within the radio receiver, so that one of the received signals of the alternatively selected antenna is It is made to be input to a radio receiver.

In addition, when using a glass antenna, the present invention provides a high frequency amplification circuit that is installed in the glass in order to increase the reception sensitivity of AM and FM broadcast waves, or to increase the reception sensitivity of AM broadcast waves or FM broadcast waves. It can be connected to any one or all of the constituent antennas of the antenna, for example the first antenna and the second antenna. This high frequency amplification circuit may be provided between the feeding point of the antenna and the switching circuit, or alternatively may be provided between the switching circuit and the antenna signal input terminal of the radio receiver. The high frequency amplification circuit may be of a tuned type or a non-tuned type.

Also, if necessary, feed points of each component antenna of the glass antenna, for example, the first antenna and the second antenna,
An attenuator for gain adjustment may be provided between either or both of the feeding points of the antenna and the switching circuit.

Note that the switching circuit does not need to be provided before the input of the radio receiver; it is installed in the radio receiver's high frequency amplification stage (RF stage) or low frequency amplification stage (AF stage).
or at any other convenient location in the circuitry of the radio receiver.

In addition, a high-frequency choke coil or a capacitor may be inserted on the power supply side of the energizing heater for defogging to prevent direct current that causes noise from flowing into the radio receiver, or the energizing heater for defogging may be It is also possible to connect high-frequency choke coils to both sides of the lead wire to float the defogging current-carrying heater at high frequency to prevent a decrease in antenna gain.

FIG. 19 is a schematic diagram of a diversity antenna system using a glass antenna of the present invention, in which a high-frequency chiyoke coil 11 is connected between the power supply lead wires 9 and 10 of the defogging current heating heater 2 and the ground. When inserted, the energizing heating heater 2 for defogging is floated at high frequency, the current induced in the heater 2 flows to the radio receiver without leakage, and the noise contained in the heating DC power supply of the energizing heating heater 2 for defogging is eliminated. The components are prevented from flowing to the radio receiver 12. This high frequency chiyoke coil 1
1, a small in-phase winding York coil capable of obtaining high impedance is used, and one winding of this coil is connected in series to the bus bar 4a, and the other winding to the bus bar 4b.

Moreover, a high frequency amplification circuit 13 is inserted between the feeding point of the first antenna 5 and the second antenna 6 and the input terminal of the radio receiver, and a high frequency amplification circuit 13 is inserted between the feeding point of the first antenna 5 and the second antenna 6 and the input terminal of the radio receiver.
The gain of the received broadcast wave signal is increased. Moreover, the first antenna 5 and the second antenna 6
A switching circuit 14 which inputs two signals and selects the signal with higher gain is connected to the first antenna 5.
and a second antenna 6, and the reception signal of the first antenna or the second antenna selected by the switching circuit 14 is inputted to the radio receiver 12.

In addition, in this invention, in order to improve omnidirectionality when receiving FM broadcast waves, multiple antennas are provided, and the reception of FM broadcasts received by the multiple antennas is adjusted according to the radio wave conditions that change from time to time. Since it uses a diversity antenna system that selectively selects and utilizes the signal with a higher gain, the above-mentioned switching circuit is capable of controlling reception in the FM broadcast wave band received by multiple antennas. The gain of the signals is compared and the signal with the higher gain is selectively selected and sent to the radio receiver. Of course, for AM broadcast waves as well as FM broadcast waves, the larger AM signal is alternatively selected and sent to the radio receiver.

Next, embodiments of the present invention will be described.

Example 1 A silver paste containing silver powder and glass frit is applied to the surface of a glass plate for a rear window of an automobile as shown in FIG. A glass antenna was manufactured by printing a pattern using a silk screen printing method, drying it, and then placing it in a heating oven and baking it at 650°C. The dimensions of each part of this glass antenna were as follows.

A=300mm, B=120mm, C=420mm, D=545mm,
E=550mm, F=555mm, G=25mm, H=40mm, I
= 350mm, J = 450mm, K = 20mm, L = 80mm α (here α is 0°, 45°,
The transmitting antenna was tilted at an angle of 90°), and the directivity characteristics of the first and second antennas of the glass antenna were measured at each angle. The results are shown in FIGS. 21 and 22. Note that this measurement is
60dB uniform field strength, frequency 80MHz and 85MHz
This was done for radio waves. In addition, Fig. 21 shows the frequency
This is the directivity characteristic at 80MHz, and Figure 22 shows the frequency.
Directional characteristics at 85MHz, as shown in Figures 21 and 22.
In the figure, a shows the directional characteristics at α=0°, b shows the directional characteristics at α=45°, and c shows the directional characteristics at α=90°. In the figure, A shows the directivity curve of the first antenna, and B shows the directivity curve of the second antenna. It is something.

As can be seen from this directional characteristic curve, even when the glass antenna of the present invention receives radio waves having various polarization plane components, the first and second antennas mutually compensate for the low gain portion. Therefore, if you select the stronger signal from the two received signals of the first antenna and the second antenna,
Even when receiving radio waves having various polarization plane components, good omnidirectionality can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a front view of a conventional glass antenna for an automobile, FIGS. 2 to 18 are front views of a glass antenna for an automobile according to a specific example of the present invention, and FIG. 19 is a front view of a glass antenna for an automobile according to a specific example of the present invention. Schematic diagram of the integrated diversity antenna system, No. 20
2 is a front view of the glass antenna for an automobile according to the first embodiment, and FIGS. 21 and 22 are directional characteristics diagrams of the glass antenna for the automobile according to the first embodiment. 1; glass plate, 2; energizing heater for defogging, 3; heater wire, 4, 4a, 4b; bus bar, 5; first antenna, 6; second antenna,
7; Feeding point of the first antenna, 8; Feeding point of the second antenna, 11; High-frequency chiyoke coil, 1
2; Radio receiver, 13; High frequency amplification circuit, 1
4; switching circuit; 15; power supply.

Claims (1)

[Scope of utility model registration request] In a glass plate for a rear window of an automobile equipped with an energizing heater for defogging, which has a large number of heater wires and a busbar for feeding power to the heater wires, a first energizing heater is installed in the upper margin of the energizing heater for defogging. In a glass antenna for an automobile in which a second antenna is provided in the lower margin, either one of the first antenna and the second antenna has an antenna pattern that is asymmetrical with respect to the longitudinal center line of the automobile. At the same time, the other antenna has a left-right symmetrical antenna pattern with respect to the center line, and a switching circuit is connected to the first antenna and the second antenna, so that the reception signal of either the first antenna or the second antenna is A glass antenna for an automobile, characterized in that the larger received signal is selected by the switching circuit and inputted to a radio receiver.