JP2004032644A - Film antenna - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film antenna capable of receiving various broadcast waves with a high gain, even when it is stuck within a range stipulated by the safety standards etc on a windshield 24 of a car. <P>SOLUTION: The film antenna is longitudinally stuck on an edge portion near the windshield 24 of the car. A narrow conductive film is longitudinally disposed on a longitudinally long transparent film 10 having an adhesive layer on its rear surface, and a longitudinally long closed rectangle is disposed on the lower part using an extended line of the conductive film as a side, thereby forming an antenna element 12, and a feeder section 14 is provided on the upper part of the antenna element 12. The film 10 is stuck on the windshield 24 with the adhesive layer on the rear surface so that the rectangle is positioned at a car body frame 30 side at the position where the longitudinal conductive film and a side of the rectangle are spaced some 25 mm from the frame 30 as a conductor. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a film antenna used by being attached to glass of a car.
[0002]
[Prior art]
2. Description of the Related Art As one type of antenna for a vehicle-mounted radio receiver, a film antenna used by being attached to a rear glass or the like is known. However, in recent years, not only the in-vehicle radio receiver, but also the TV receiver and the TV tuner of the car navigation unit are often installed on the front console together with the image monitor. Therefore, it has been proposed to attach a film antenna to a windshield in order to improve problems such as routing of cables and the like.
[0003]
However, if anything that obstructs the driver's view, such as a film antenna, is stuck on the windshield in a dark manner, it may hinder safe driving. Therefore, in the security standards, Article 29, Paragraph 4, Item 7, a range where the film antenna can be attached to the windshield is specified. One example of a range permitted by this security standard is that the lateral edge of the windshield is within 25 mm of the vehicle frame. In addition, an inspection seal or the like is stuck on the upper side of the windshield, and the range in which the film antenna can be arranged is extremely limited.
[0004]
For this reason, the conventional film antenna to be attached to the lateral edge of the windshield requires a single linear antenna element to be vertically disposed along the lateral edge of the windshield. I can't do it.
[0005]
[Problems to be solved by the invention]
In the above-described film antenna, the length in the vertical direction of the windshield is not sufficient, and the length of a range that can be used for an inspection seal having a conductive thin film is narrowed. At most, it can only be set to about 400 mm. For this reason, AM / FM broadcast waves cannot be received at a high gain, and TV broadcast waves cannot be sufficiently received. Furthermore, FM multiplex broadcast waves including traffic information broadcasts such as VICS cannot be received well.
[0006]
The present invention has been made to improve the disadvantages of the conventional film antenna as described above, and is capable of receiving various broadcast waves with a high gain even when the antenna is attached within a range specified by security standards. It is an object to provide a film antenna that can be used.
[0007]
[Means for Solving the Problems]
In order to achieve this object, a film antenna according to the present invention is a film antenna which is vertically attached to a lateral edge portion of a car glass, and has a vertically arranged adhesive layer on one side. On a long transparent film, a narrow conductive film or a thin conductive line is disposed in the vertical direction, and a vertically long closed rectangle is disposed in the lower part with an extension thereof as one side as an antenna element, and A feeder is provided at the upper end of the antenna element, and one side of the rectangular conductive film or conductive line and the rectangle is positioned about 25 mm away from a vehicle frame as a conductor so that the rectangle is on the vehicle frame side. Then, the transparent film can be attached to the glass.
[0008]
In addition, a film antenna which is vertically stuck to a lateral edge portion of a car glass, wherein a narrow conductive film or a thin conductive film is formed on a vertically long transparent film having an adhesive layer disposed on one side. The wire is arranged vertically in the shape of a crank and an extended line is set as one side, and a vertically long closed rectangle is arranged in the lower part to form an antenna element, and a feeder is provided on the crank-shaped upper end of the antenna element. The longitudinal crank-shaped part and one side of the rectangle are arranged such that the rectangle is on the vehicle frame side at a position about 25 mm away from a vehicle frame as a conductor, and the glass is transparent. You may comprise so that a film may be stuck.
[0009]
Then, the total length of the antenna element in the vertical direction may be set to about 400 mm, and the length and width of the rectangle may be set to 70 mm and 20 mm, respectively.
[0010]
Further, the upper end of the antenna element is bent toward the vehicle frame, and the feeder is provided at the tip of the antenna element, and the transparent feeder is attached to the glass. It is also possible to configure so as to face the masking portion of the section.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view of a first embodiment of the film antenna of the present invention. FIG. 2 is an enlarged cross-sectional view taken along the line AA of FIG. FIG. 3 is an enlarged view taken along a line BB in FIG. 1. FIG. 4 is an enlarged partial view of a feeder of the film antenna of the present invention in FIG. FIG. 5 is a view showing a state in which the film antenna according to the first embodiment of the present invention shown in FIG. 1 is attached to a lateral edge of a windshield of a car. FIG. 6 is an antenna characteristic diagram of the film antenna of the present invention shown in FIG. FIG. 7 is an antenna characteristic diagram of the film antenna in which the length in the length direction of the rectangle is changed from 70 mm to 140 mm. FIG. 8 is an antenna characteristic diagram of the film antenna in which the dimension in the width direction of the rectangle is changed from 20 mm to 25 mm.
[0012]
On the surface of the vertically long transparent film 10 made of an insulating material, a narrow conductive film having a width of 0.25 mm or less is disposed in the longitudinal direction, and a lower portion of the transparent film 10 with its extension line as one side. The antenna element 12 is formed by disposing a closed rectangle that is long in the vertical direction. The upper end of the conductive film is bent toward the side where the rectangle is provided, and a power supply unit 14 is formed at the end. The conductive film forming the antenna element 12 and the power supply unit 14 is appropriately formed by printing conductive ink or the like. In addition, a transparent resist 16 is provided on the conductive film except for the power supply unit 14, as shown in FIGS. 2 to 4, to protect the conductive film. An adhesive layer 18 is provided on the back surface of the transparent film 10, and a release sheet 20 is provided so as to cover the adhesive layer 18.
[0013]
Here, the adhesive layer 18 is transparent and may be made of a transparent double-sided tape. The release sheet 20 may be transparent or opaque. Further, the conductive film forming the antenna element 12 is opaque in the above embodiment, but may be transparent. Moreover, instead of the conductive film, a thin conductive wire may be appropriately fixed to the transparent film 10.
[0014]
The dimensions of the first embodiment of the film antenna of the present invention are as follows: the total length in the vertical direction of the antenna element 12 is about 400 mm at 381 mm, and the vertical and horizontal dimensions of the rectangle are 70 mm and 20 mm. The bending length up to the power supply section 14 at the upper end is 27 mm.
[0015]
As shown in FIG. 5, the film antenna of the present invention having such a structure is formed by peeling off the release sheet 20 and attaching the adhesive layer 18 to the lateral edge of the inner surface of the windshield 24. From the vehicle frame 30 as a conductor, the longitudinal conductive film and one side of the rectangle are positioned so that the rectangle is on the side of the vehicle frame 30 so as to be attached at a distance of about 25 mm within the specified range of the safety standards. Will be arranged. The power supply unit 14 is attached to a masking (commonly referred to as black ceramic) portion 32 provided on a peripheral portion of the windshield 24. Further, a power supply connector 34 is disposed so as to elastically contact the power supply section 14 with a spring connector, and the antenna element 12 is appropriately electrically connected to a receiver or a tuner.
[0016]
FIG. 6 shows antenna characteristics measured by attaching the film antenna of the present invention to the windshield 24 as shown in FIG. As is clear from FIG. 6, the film antenna of the present invention has a band centered at 82 MHz, and can be used as a receiving antenna in the FM broadcast wave, the FM multiplex information wave, and the VHF-LOW band of TV.
[0017]
FIGS. 7 and 8 show how the antenna characteristics change depending on the rectangular dimensions of the lower part of the antenna element 12. FIG. In FIG. 7, the length of the rectangular shape of the antenna element 12 in the vertical direction is changed from 70 mm to 140 mm. The center frequency is slightly reduced to about 90 MHz. This is presumed to be due to the fact that by increasing the length of the rectangle in the vertical direction, the distance attached to the vehicle frame 30 was increased, and the coupling capacity with the vehicle frame 30 was increased. You. Thus, if the length of the rectangle in the vertical direction is reduced, the center frequency is expected to increase. In FIG. 8, the width of the rectangle of the antenna element 12 is changed from 20 mm to 25 mm. The center frequency is greatly reduced to about 70 MHz. This is presumably due to the fact that one side of the rectangle is close to the vehicle frame 30 and the coupling capacity with the vehicle frame 30 is increased. Thus, it is predicted that if the width of the rectangle is reduced and the distance between the rectangle and the vehicle frame 30 is increased, the coupling capacity decreases and the center frequency increases. Furthermore, from general knowledge of antenna technology, it is conceivable that the rectangle in the lower part of the antenna element 12 contributes to an increase in bandwidth. Therefore, like the film antenna of the present invention, the rectangular and vertical dimensions of the rectangle are appropriately set even if the rectangle is attached to the windshield 24 and the range and length of the attachment are restricted. It is possible to obtain antenna characteristics in a band of a desired center frequency.
[0018]
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 9 is a front view of a second embodiment of the film antenna of the present invention. FIG. 10 is a view showing a state where the film antenna according to the second embodiment of the present invention shown in FIG. 9 is attached to a lateral edge of a windshield of a car. 9 and 10, the same or equivalent members as those in FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description will be omitted.
[0019]
The second embodiment is different from the first embodiment in that a conductive film is vertically arranged in a crank shape on the surface of a transparent film 10 which is long in the vertical direction, and a rectangle is formed with an extension of one side. That is, the antenna element 42 is formed. The crank-shaped upper part is on the side where the rectangle is arranged, and the power supply part 14 is provided at the crank-shaped upper end part.
[0020]
Then, as shown in FIG. 10, the windshield 24 is disposed on the lateral edge of the windshield 24 so as to be spaced apart from the vehicle frame 30 by about 25 mm. Here, the crank-shaped upper portion and the power supply portion 14 are attached to face the masking portion 32. In the state where the broadcast wave is received, the upper portion of the antenna element 42 does not become a large voltage, and even in a state in which the antenna element 42 is close to the vehicle frame 30, there is no large capacitive coupling, and the antenna characteristics do not change significantly. Antenna characteristics similar to those of the first embodiment can be obtained.
[0021]
In the above-described embodiment, the description has been given of attaching the film antenna of the present invention to the lateral edge of the windshield 24. However, the present invention is not limited thereto, and the film antenna may be attached to the lateral edge of the rear glass. Of course, it is also possible to use it. Furthermore, it is also possible to stick on the side glass of the car. Further, in the above embodiment, the antenna element 12 is provided on the front surface of the transparent film 10 and the adhesive layer 18 is provided on the back surface. However, the antenna element may be provided on any surface of the transparent film 10. Then, the adhesive layer 18 may be provided on one surface of the transparent film 10. Further, the antenna element 12 may be disposed so as to be sandwiched between two transparent films.
[0022]
【The invention's effect】
As described above, since the film antenna of the present invention is constituted, the following special effects can be obtained.
[0023]
The film antenna according to claim 1 or 2 is attached to a lateral edge of a windshield within a range regulated by a vehicle windshield security standard, so that an FM broadcast wave and an FM multiplex information wave are provided. Have good antenna characteristics.
[0024]
The film antenna according to claim 3 has a vertical direction of 400 mm, and can be used for a light vehicle having a short vertical size of a windshield.
[0025]
In the film antenna according to claim 4, since the power supply portion is attached to the masking portion on the peripheral portion of the glass, the power supply portion and the power supply connector electrically connected to the power supply portion are hidden from the outside of the car by the masking portion, Excellent aesthetics.
[Brief description of the drawings]
FIG. 1 is a front view of a first embodiment of a film antenna of the present invention.
FIG. 2 is an enlarged view taken along the line AA of FIG. 1;
FIG. 3 is an enlarged view taken along a line BB in FIG. 1;
FIG. 4 is an enlarged partial view of a feeder of the film antenna of the present invention in FIG. 1;
FIG. 5 is a view showing a state in which the film antenna of the first embodiment of the present invention shown in FIG. 1 is attached to a lateral edge of a windshield of a vehicle.
6 is an antenna characteristic diagram of the film antenna of the present invention in FIG.
FIG. 7 is an antenna characteristic diagram of a film antenna in which a length dimension of a rectangle is changed from 70 mm to 140 mm.
FIG. 8 is an antenna characteristic diagram of a film antenna in which a dimension in a width direction of a rectangle is changed from 20 mm to 25 mm.
FIG. 9 is a front view of a second embodiment of the film antenna of the present invention.
FIG. 10 is a view showing a state in which the film antenna according to the second embodiment of the present invention shown in FIG. 9 is attached to a lateral edge of a windshield of a vehicle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Transparent film 12, 42 Antenna element 14 Power supply part 16 Resist 18 Adhesive layer 20 Release sheet 24 Windshield 30 Vehicle frame 32 Masking part 34 Power supply connector

Claims (4)

A film antenna that is stuck vertically on the lateral edge of car glass, and has a long conductive film with an adhesive layer on one side, a narrow conductive film or a thin conductive wire. A vertically long closed rectangle is disposed in the lower part with the extension of the side as one side and an antenna element is provided, and a feeder is provided at the upper end of the antenna element, The transparent film can be attached to the glass such that the rectangle is on the vehicle frame side at a position about 25 mm away from the vehicle frame as a conductor, with one side of the conductive film or the conductive wire and the rectangle. A film antenna characterized in that: A film antenna that is stuck vertically on the lateral edge of car glass, and a narrow conductive film or a thin conductive wire is applied to a vertically long transparent film having an adhesive layer disposed on one side. The antenna element is arranged vertically in a crank shape and an extended line is set as one side, and a vertically long closed rectangle is arranged in a lower portion as an antenna element, and a feeder is provided at a crank-shaped upper end of the antenna element. The vertical crank-shaped part and one side of the rectangle are arranged such that the rectangle is on the vehicle frame side at a position about 25 mm away from a vehicle frame as a conductor, and the transparent film is formed on the glass. A film antenna characterized in that it can be attached. 3. The film antenna according to claim 1, wherein a length of the antenna element in the vertical direction is set to about 400 mm, and a length and a width of the rectangle are set to 70 mm and 20 mm, respectively. . 2. The film antenna according to claim 1, wherein an upper end of the antenna element is bent toward the vehicle frame, the feeder is provided at an end of the antenna element, and the transparent film is attached to the glass. 3. A film antenna, wherein a power supply unit is configured to face a masking portion of a peripheral portion of the glass.

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