JP2024020774A - vehicle antenna - Google Patents

Abstract

To provide a vehicle antenna capable of receiving radio waves in a predetermined frequency band with a desired gain in a glass plate construct that is attached to a frame-shaped resin plate and includes a conductive film.SOLUTION: A vehicle antenna 1 includes: a glass plate construct 20 including a first glass plate having a first main surface and a second main surface and a conductive film 54 disposed on the second main surface side; a frame-shaped resin plate 10 that overlaps a peripheral portion 21 of the glass plate construct 20 in a plan view of the first glass plate; and an antenna 40 having a power feeding unit 41, an element 42, and a grounding portion 43. The glass plate construct 20 has a conductive region 20A including the conductive film 54 in the plan view of the first glass plate, the ground portion 43 is electrically connected to the conductive film 54, and the power feeding unit 41 and the element 42 are arranged outside the conductive region 20A.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle antenna.

In recent years, vehicle openings, especially vehicle window glasses, have been coated with (transparent) conductive films such as Low-E (Low Emissivity) and heat ray reflective films, or have visible light transmittance changed electrically (actively). Thermal/optical added values are provided, such as light control films and the like. For example, the following Patent Document 1 is known as a device that utilizes such a conductive film as an antenna.

The vehicle window assembly disclosed in U.S. Pat. No. 5,300,303 includes a glass ply and an electrically conductive coating positioned on the surface of the glass ply. The conductive coating has an outer periphery adapted to be spaced from an inner metal edge of the vehicle frame to define an antenna slot. The conductive coating includes at least one removed portion adjacent the outer periphery, the removed portion dimensioned to tune the antenna slot to a desired resonant frequency.

Special Publication No. 2013-544045

On the other hand, when a dielectric material such as glass is coated with a conductive film, it becomes possible to create a glass that receives radio waves from predetermined broadcast waves by placing a linear conductor pattern on the vehicle window glass, just like in conventional vehicle window glass. There were cases in which the desired antenna gain could not be obtained as an antenna.
Furthermore, the technique disclosed in Patent Document 1 allows the antenna to be grounded at the inner metal edge of the vehicle frame. However, if the vehicle frame is made of resin, the antenna cannot be grounded from the vehicle frame, and a desired antenna gain may not be stably obtained.

The present invention provides a vehicle antenna capable of receiving radio waves in a predetermined frequency band with a desired gain in a glass plate structure that is attached to a frame-shaped resin plate and includes a conductive film.

In order to solve the above problems, the present invention includes the following configuration.
[1] A glass plate structure including a first glass plate having a first main surface and a second main surface opposite to the first main surface, and a conductive film disposed on the second main surface side. and a frame-shaped resin plate that overlaps a peripheral portion of the glass plate structure when viewed from the top of the first glass plate, an antenna having a power feeding section, an element connected to the power feeding section, and a grounding section. , the glass plate structure has a conductive region including the conductive film in a plan view of the first glass plate, the ground portion is electrically connected to the conductive film, and the power supply portion and the element is a vehicle antenna disposed outside the conductive region.

[2] The glass plate structure has a non-conductive region that does not include the conductive film in a plan view of the first glass plate, and the power feeding section and the element are arranged in the non-conductive region and the resin plate. The vehicle antenna according to [1], which is arranged on at least one side.

[3] The non-conductive region extends in a band shape of a predetermined width along the edge of the glass plate structure when viewed from above of the first glass plate, and the element is disposed in the non-conductive region. The vehicle antenna according to [2].

[4] The vehicle antenna according to [2], wherein the non-conductive region is formed with the predetermined width of 5 mm to 140 mm.

[5] The element extends substantially parallel to the edge of the non-conductive region, and is disposed at least 5 mm from the boundary between the conductive region and the non-conductive region in a plan view of the first glass plate. The vehicle antenna according to [4].

[6] The glass plate structure has an intermediate film containing a resin and a second glass plate in this order on the second main surface side of the first glass plate, and the second glass plate has a resin-containing intermediate film and a second glass plate on the second main surface side of the first glass plate. The vehicle antenna according to any one of [1] to [5], comprising a third main surface on the side of the interlayer film and a fourth main surface on the opposite side to the interlayer film side.

[7] The vehicle antenna according to [6], wherein the conductive film is disposed on at least one of the second main surface and the third main surface.

[8] The vehicle antenna according to [6] or [7], wherein the antenna is arranged on the fourth main surface.

[9] The vehicle antenna according to [6] or [7], wherein the antenna is arranged on the second main surface or the third main surface.

[10] The vehicle antenna according to [9], wherein the conductive film is disposed on a main surface different from the antenna, out of the second main surface or the third main surface.

[11] The intermediate film includes a first intermediate film and a second intermediate film, and the conductive film is disposed between the first intermediate film and the second intermediate film, [6] The vehicle antenna according to any one of [10].

[12] The vehicle antenna according to [11], wherein the conductive film is a conductor included in a light control film.

[13] The length L of the element is 0.70×(where λ is the wavelength in the air at the center frequency of the frequency band received by the antenna, and k is the wavelength shortening rate of the glass plate structure. The vehicle antenna according to any one of [1] to [12], which satisfies 1/4)×λ×k≦L≦1.30×(1/4)×λ×k.

[14] The vehicle antenna according to any one of [1] to [13], wherein the conductive film has a sheet resistance of 5Ω/□ or less.

[15] The vehicle antenna according to [14], wherein the conductive film includes a heat ray reflective film.

[16] The conductive film has a sheet resistance higher than 5Ω/□, and has a conductive frame having a lower resistance than the conductive film around the outer periphery of the conductive region in a plan view of the first glass plate. [1] The vehicle antenna according to any one of [13].

[17] The vehicle antenna according to [16], wherein the conductive film includes a conductor for a low-emission film.

[18] The vehicle antenna according to any one of [2] to [17], wherein the non-conductive region extends in the horizontal direction when the glass plate structure is attached to a vehicle.

[19] The non-conductive region according to any one of [2] to [18] is inclined in a range of 0° to 75° with respect to the vertical direction when the glass plate structure is attached to a vehicle. Vehicle antenna.

[20] The vehicle antenna according to any one of [1] to [19], wherein the antenna receives radio waves of at least one of a VHF band and a UHF band frequency.

[21] The vehicle antenna according to any one of [1] to [20], wherein the glass plate structure is a rear glass.

According to the present invention, radio waves in a predetermined frequency band can be received with a desired gain in a glass plate structure that is attached to a frame-shaped resin plate and includes a conductive film.

FIG. 1 is a plan view of a vehicle antenna according to a first embodiment of the present invention. FIG. 1 is an exploded perspective view of a vehicle antenna according to a first embodiment of the present invention. 2 is a sectional view taken along arrows III-III shown in FIG. 1. FIG. FIG. 3 is an exploded perspective view of a vehicle antenna according to a second embodiment of the present invention. FIG. 3 is a cross-sectional view of a vehicle antenna according to a second embodiment of the present invention. FIG. 3 is an exploded perspective view of a vehicle antenna according to a third embodiment of the present invention. FIG. 3 is a sectional view of a vehicle antenna according to a third embodiment of the present invention. FIG. 7 is an exploded perspective view of a vehicle antenna according to a fourth embodiment of the present invention. FIG. 1 is a plan view of a vehicle antenna according to a first embodiment of the present invention. 2 is a graph showing simulation results of the antenna gain in the frequency band of FM broadcast waves of the vehicle antenna according to the first example. 3 is a graph showing a simulation result of the antenna gain in band III of the DAB standard of the vehicle antenna according to the first example. FIG. 3 is a plan view of a vehicle antenna according to a second embodiment of the present invention. 7 is a graph showing simulation results of the antenna gain in the frequency band of FM broadcast waves of the vehicle antenna according to the second example. It is a graph which shows the simulation result of the antenna gain in Band III of DAB standard of the vehicle antenna 1 by 2nd Example. FIG. 3 is a plan view of a vehicle antenna 1 according to a third embodiment of the present invention. It is a graph which shows the simulation result of the antenna gain of the vertically polarized wave in the frequency band of the FM broadcast wave of the vehicle antenna 1 by 3rd Example. 12 is a graph showing simulation results of vertically polarized antenna gain in band III of the DAB standard of a vehicle antenna according to a third example. It is a graph which shows the simulation result of the vertically polarized antenna gain in the frequency band of the FM broadcast wave of the vehicle antenna by 4th Example. It is a graph which shows the simulation result of the vertically polarized antenna gain in Band III of the DAB standard of the vehicle antenna according to the fourth example.

Hereinafter, a vehicle antenna according to an embodiment of the present invention will be described with reference to the drawings. Note that for ease of understanding, the scale of each part in the drawings may differ from the actual scale. In parallel, perpendicular, perpendicular, horizontal, perpendicular, up and down, left and right directions, deviations are allowed to an extent that does not impair the effects of the embodiment. The shape of the corner portion is not limited to a right angle, but may be rounded in an arcuate shape. Parallel, right angle, perpendicular, horizontal, and perpendicular may include substantially parallel, substantially perpendicular, substantially orthogonal, substantially horizontal, and substantially perpendicular.

For example, "substantially parallel" and "substantially horizontal" may include an angle of ±15° or less with respect to a reference line (parallel line, horizontal line), a range of ±10°, a range of ±5°, an angle of ±3°. It can be a range. For example, when the angle with respect to the reference line (parallel line, horizontal line) approaches 0°, the design of the antenna improves.
Substantially right angle, substantially orthogonal, and substantially perpendicular may include, for example, ±15° or less with respect to 90° of the angle formed by two reference lines or reference planes, or may include a range of ±10° with respect to 90°, It may be in the range of ±5° with respect to 90°, or may be in the range of ±3° with respect to 90°. For example, when the angle between the two reference lines or reference planes approaches 90°, the design of the antenna improves.

Further, below, the positional relationship of each member may be explained while referring to the XYZ coordinates set in the drawings as necessary. In this XYZ coordinate system, the X-axis direction, Y-axis direction, and Z-axis direction represent a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. The XY plane, YZ plane, and ZX plane are, respectively, a virtual plane parallel to the X-axis direction and the Y-axis direction, a virtual plane parallel to the Y-axis direction and the Z-axis direction, and a virtual plane parallel to the Z-axis direction and the X-axis direction. represents.

In the following, the X-axis direction, Y-axis direction, and Z-axis direction respectively refer to the left-right direction (horizontal direction) of the glass plate structure, which will be described later in the vehicle antenna, the vertical direction (vertical direction) of the glass plate structure, and the glass plate structure. Represents the thickness direction of the structure (normal direction to the main surface). Further, "~" indicating a numerical range means that the numerical values written before and after it are included as the lower limit and upper limit.

An example of application of the vehicle antenna in this embodiment is a rear window attached to the rear of a vehicle. However, the vehicle antenna in this embodiment may be a windshield attached to the front of the vehicle, a side glass attached to the side of the vehicle, or a roof glass attached to the ceiling of the vehicle. Note that the vehicle window glass to which the vehicle antenna can be applied is not limited to these examples.

[First embodiment]
FIG. 1 is a plan view of a vehicle antenna 1 according to a first embodiment of the present invention. FIG. 2 is an exploded perspective view of the vehicle antenna 1 according to the first embodiment of the present invention. FIG. 3 is a sectional view taken along arrows III-III shown in FIG.
A vehicle antenna 1 shown in FIG. 1 is applied to a rear window attached to the rear of a vehicle. In addition, in FIG. 1, the vehicle antenna 1 is shown from the viewpoint from inside the vehicle (viewed from inside the vehicle). The vehicle antenna 1 is connected via a transmission line 2 to a signal processing device (amplifier module), not shown, provided on the vehicle body side of the vehicle.

The transmission line 2 is, for example, a coaxial cable, but microstrip lines, strip lines, coplanar lines, slot lines, etc. can also be used. Hereinafter, unless otherwise specified, the transmission line 2 will be described as a coaxial cable. The transmission line 2 includes an inner conductor 2a and an outer conductor 2b that covers the outside of the inner conductor 2a via an insulator. The internal conductor 2a is connected to a power feeding section 41 of an antenna 40, which will be described later. Further, the outer conductor 2b is connected to a grounding portion 43 of an antenna 40, which will be described later, via a connecting wire 2c.

The vehicle antenna 1 includes a resin plate 10, a glass plate structure 20, a defogger 30, and an antenna 40. In addition, when the glass plate structure 20 is a window glass other than a rear glass, the defogger 30 is not essential. The glass plate structure 20 has a substantially rectangular outer shape in plan view. The peripheral portion 21 of the glass plate structure 20 includes an upper edge 22 and a lower edge 23 that face each other in the vertical direction, and a left edge 24 and a right edge 25 that face each other in the horizontal direction.

The resin plate 10 constitutes at least a portion of the rear part of the vehicle. The resin plate 10 has a rectangular opening 11 when viewed from the Z-axis direction, and is formed in a frame shape that overlaps the peripheral portion 21 of the glass plate structure 20 in the thickness direction (Z-axis direction). A housing groove 12 is formed at the periphery of the opening 11 to accommodate the peripheral portion 21 of the glass plate structure 20 .

The accommodation groove 12 is formed on the outer surface 10a side of the resin plate 10, as shown in FIG. The positive side in the Z-axis direction represents the outside of the vehicle, and the negative side in the Z-axis direction represents the inside of the vehicle. The outer surface 10a is a surface facing outside the vehicle, and the inner surface 10b is a surface facing inside the vehicle. The peripheral portion 21 of the glass plate structure 20 is attached to the housing groove 12 of the resin plate 10 via an adhesive 13 such as urethane resin.

As shown in FIG. 1, the defogger 30 has a conductive pattern provided on the glass plate structure 20. The defogger 30 is of an electrical heating type, and includes a first bus bar 31a, a second bus bar 31b, and a plurality of heater wires 32 disposed between the first bus bar 31a and the second bus bar 31b. The heater wire 32 is arranged between the first bus bar 31a and the second bus bar 31b, and a DC current is applied to the heater wire 32 by applying a voltage (DC voltage) via the first bus bar 31a and the second bus bar 31b. flows and heats the glass plate structure 20. By heating the glass plate structure 20 in this manner, dew condensation (fogging) on the glass plate structure 20 is removed.

The first bus bar 31a and the second bus bar 31b are arranged on both left and right sides of the glass plate structure 20. The first bus bar 31a extends vertically along the left edge 24 of the glass plate structure 20. The second bus bar 31b extends in the vertical direction along the right edge 25 of the glass plate structure 20. The first bus bar 31a and the second bus bar 31b feed power to heater wires 32 that extend in the horizontal direction so as to run parallel to each other. Note that the number of heater wires 32 may be greater or less than the seven illustrated.

The antenna 40 is configured to be able to receive radio waves in a predetermined frequency band. The antenna 40 may be formed to be able to receive radio waves in one frequency band, or may be formed to be able to receive radio waves in two or more different frequency bands. The two different frequency bands may be a combination in which some of the frequency bands overlap, or may be a combination in which the frequency bands do not overlap at all. Hereinafter, unless otherwise specified, the antenna 40 will be described as being formed to be able to receive radio waves in two different frequency bands as radio waves in a predetermined frequency band, and resonating at the frequencies in the two different frequency bands. However, the same applies to each antenna in the second embodiment and subsequent embodiments in this specification. For example, the antenna 40 receives at least one of a VHF band (30 MHz to 300 MHz) radio waves and a UHF band (300 MHz to 3 GHz) radio waves.

The antenna 40 of this embodiment receives, for example, FM broadcast waves (76 MHz to 108 MHz) as radio waves in the VHF band. Further, the antenna 40 of the present embodiment receives radio waves of Band III (174 MHz to 240 MHz) of the DAB standard, for example, as radio waves of the VHF band. Note that the antenna 40 may receive radio waves of terrestrial digital television broadcast waves (470 MHz to 710 MHz) in the UHF band, and radio waves of AM broadcast waves (522 kHz to 1710 kHz) in the MF band.

As shown in FIG. 2, the glass plate structure 20 includes a first glass plate 51, a second glass plate 52, an intermediate film 53, and a conductive film 54. In addition, in FIG. 2, the constituent elements of the glass plate structure 20 are shown separated in the Z-axis direction.
The first glass plate 51 has a first main surface 51a facing the positive side in the Z-axis direction, and a second main surface 51b facing the opposite side (negative side in the Z-axis direction) from the first main surface 51a in the Z-axis direction. It is a plate-shaped dielectric material having the following. The first glass plate 51 may be transparent or semitransparent. The first main surface 51a is a surface facing outside the vehicle, and the second main surface 51b is a surface facing inside the vehicle.

The glass plate structure 20 can be exemplified by a laminated glass having a conductive film 54, an intermediate film 53, and a second glass plate 52 in this order on the second main surface 51b side of the first glass plate 51. The second glass plate 52 has a third main surface 52a facing the positive side in the Z-axis direction, and a fourth main surface 52b facing the opposite side (negative side in the Z-axis direction) from the third main surface 52a in the Z-axis direction. It is a plate-shaped dielectric material having the following. The second glass plate 52 may be transparent or semitransparent. The third main surface 52a is a surface facing outside the vehicle, and the fourth main surface 52b is a surface facing inside the vehicle. Note that for the first glass plate 51 and the second glass plate 52, conventionally known inorganic glass or organic glass can be selected. For example, the first glass plate 51 may be made of inorganic glass such as soda lime glass, and the second glass plate 52 may be made of organic glass such as polycarbonate resin. Hereinafter, unless otherwise specified, the first glass plate 51 and the second glass plate 52 will be described as inorganic glass.

A defogger 30, an antenna 40, and a light shielding section 26 are provided on the fourth main surface 52b side of the second glass plate 52. The light shielding part 26 is, for example, a light shielding layer that blocks visible light, and is formed in a frame shape along the periphery of the fourth main surface 52b of the second glass plate 52. In other words, the inner edge of the light shielding part 26 is located inside the inner edge of the opening 11 of the resin plate 10. The light-shielding layer is an opaque colored ceramic layer, and the color is arbitrary, but dark colors such as black, brown, gray, and dark blue, or white are preferable, and black is more preferable.

In a plan view of the glass plate structure 20, the light shielding part 26 overlaps at least a portion of the antenna 40 and the defogger 30. In the example shown in FIG. 1, an antenna 40 and at least a portion of the defogger 30 (first bus bar 31a and second bus bar 31b) are formed on the light shielding part 26. When the glass plate structure 20 is viewed from above, the light blocking portion 26 overlaps at least a portion of the antenna 40 and the defogger 30, making it difficult to see the overlapping portion, improving the appearance of the rear glass and the design of the vehicle. Preferably, it is more preferable that all of them overlap. Note that the light shielding portion 26 may be provided on at least one of the second main surface 51b of the first glass plate 51 and the third main surface 52a of the second glass plate 52.

The intermediate film 53 is a transparent or semi-transparent dielectric material interposed between the first glass plate 51 and the second glass plate 52, as shown in FIG. The first glass plate 51 and the second glass plate 52 are joined by an intermediate film 53. Examples of the intermediate film 53 include thermoplastic polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), and cycloolefin polymer (COP). Note that the dielectric constant of the intermediate film 53 is preferably 2.4 or more and 3.5 or less. The intermediate film 53 may be placed between the conductive film 54 and the second glass plate 52 or between the first glass plate 51 and the conductive film 54. In other words, the conductive film 54 is not limited to the arrangement shown in FIG. 2, but may be arranged on the third main surface 52a side of the second glass plate 52. Furthermore, the intermediate film 53 may be arranged both between the conductive film 54 and the second glass plate 52 and between the first glass plate 51 and the conductive film 54.

In FIG. 2, the conductive film 54 is a planar conductor located on the second main surface 51b side with respect to the first glass plate 51. The conductive film 54 may be a conductor in contact with the second main surface 51b, or may be a conductor placed on the second main surface 51b side via a transparent or semitransparent dielectric (not shown). Furthermore, the conductive film 54 may be transparent or semitransparent. The conductive film 54 includes a conductive film for heat ray reflection (heat ray reflection film), a conductive film for low radiation (Low-E (Low Emissivity) coat), and a light control film that can actively change visible light transmittance. Examples include a conductive film.

The conductive film 54 of this embodiment is a heat ray reflective film that is provided on the second main surface 51b of the first glass plate 51 disposed on the outside of the vehicle, and reflects heat rays contained in sunlight etc. directed from the outside of the vehicle toward the inside of the vehicle. It is. A typical heat ray reflective film is a metal film, and examples of the metal film include a silver (Ag) film. The heat ray reflective film may be a laminate of multiple types of films, or may be a film coated on a resin film such as polyethylene terephthalate (PET) by vapor deposition or the like. The sheet resistance of the conductive film 54 is preferably 5Ω/□ (ohms per square) or less.

The conductive film 54 has a smaller area than the other glass plate structures 20 (first glass plate 51, second glass plate 52, intermediate film 53). For example, the conductive film 54 may have the same dimension in the left-right direction as the other glass plate structures 20, but may have a shorter dimension in the vertical direction than the other glass plate structures 20. Specifically, the conductive film 54 may have its lower edge coincident with the lower edge 23 of the glass plate structure 20 and its upper edge 22 a at a position lower than the upper edge 22 of the glass plate structure 20 . In this way, in the glass plate structure 20, in a plan view of the first glass plate 51, a conductive region 20A including the conductive film 54 and a non-conductive region 20B not including the conductive film 54 are formed. . Note that in a plan view of the glass plate structure 20, each outer edge of the conductive film 54 does not necessarily have to coincide with the left edge 24, right edge 25, and lower edge 23 of the glass plate structure 20; It may be arranged inside at least one of the edges.

In the example shown in FIG. 1, the non-conductive region 20B extends in a band shape of a predetermined width along the upper edge 22 of the glass plate structure 20 when the first glass plate 51 is viewed from above. For example, the non-conductive region 20B is preferably formed with a width of 5 mm to 140 mm, more preferably formed with a width of 5 mm to 120 mm, and even more preferably formed with a width of 5 mm to 100 mm. The width of the non-conductive region 20B means the dimension of the non-conductive region 20B in the vertical direction (the distance in the vertical direction from the upper edge 22 of the glass plate structure 20 to the upper edge 22a of the conductive film 54 shown in FIG. 2). . Note that the non-conductive region 20B is not limited to the upper edge 22 but may be formed on at least one of the lower edge 23, the left edge 24, and the right edge 25 as long as it is an edge of the glass plate structure 20. .

The antenna 40 is a glass antenna provided on the fourth main surface 52b side of the second glass plate 52. The antenna 40 is arranged in a region above the defogger 30 when the glass plate structure 20 is attached to the vehicle. Note that when the glass plate structure 20 is attached to the vehicle, when the resin plate 10 constitutes at least a part of the back door at the rear of the vehicle, it is when the back door is closed. The non-conductive region 20B extends in the horizontal direction when the glass plate structure 20 is attached to the resin plate 10. Further, the non-conductive region 20B is arranged so as to be inclined within a range of 0° to 75° with respect to the vertical direction when the glass plate structure 20 is attached to a vehicle. Note that the inclination angle may be in the range of 0° to 60°, may be in the range of 0° to 45°, or may be in the range of 0° to 30°.

As shown in FIG. 1, the antenna 40 includes a power feeding section 41, an element 42 connected to the power feeding section 41, and a grounding section 43. The power feeding section 41 is a conductor pattern formed in a rectangular shape, and is connected to the internal conductor 2a of the transmission line 2. Note that the shape of the power feeding section 41 may be other shapes such as a circle or another polygon. In FIG. 1, the power supply part 41 is located in the non-conductive region 20B of the glass plate structure 20, near the left edge 24 of the glass plate structure 20. It may be arranged near the right edge 25 of the plate structure 20. Furthermore, the antenna 40 may have a conductive pattern (element) (not shown) connected to the ground portion 43 and extending in an arbitrary direction.

The element 42 is a linear conductor pattern that is bent in an L-shape from the power feeding section 41 along the left edge 24 and the upper edge 22 of the glass plate structure 20 . A portion of the element 42 along the upper edge 22 extends in the left-right direction substantially parallel to the non-conductive region 20B, and is separated from the boundary 20C between the conductive region 20A and the non-conductive region 20B by 5 mm or more in a plan view of the first glass plate 51. They may be spaced apart by 10 mm or more, or may be spaced apart by 15 mm or more. Further, if the distance is too far, the area of the conductive region 20A will be narrowed, so the distance may be 100 mm or less, preferably 90 mm or less, and more preferably 80 mm or less. Note that the boundary 20C is the upper edge 22a portion of the conductive film 54 shown in FIG. 2, and is the boundary line between the conductive region 20A and the non-conductive region 20B.

The length L of the element 42 is determined by the following relational expression (1), where λ is the wavelength in the air at the center frequency of the frequency band received by the antenna 40, and k is the wavelength shortening rate of the glass plate structure 20. It's good to be satisfied. Thereby, the antenna characteristics of the vehicle antenna 1 can be improved. Specifically, the vertical portion of the element 42 functions as a low frequency improving element for antenna characteristics. Furthermore, the horizontal portion of element 42 functions as a peak shifting element for antenna characteristics.
0.70×(1/4)×λ×k≦L≦1.30×(1/4)×λ×k…(1)

Also, the length L is
0.72×(1/4)×λ×k≦L≦1.28×(1/4)×λ×k…(1a)
It is more preferable to satisfy the following.
Also, the length L is
0.74×(1/4)×λ×k ≦ L ≦ 1.26×(1/4)×λ×k…(1b)
It is even more preferable to satisfy the following.

The length L of the element 42 is the sum of the length of the portion of the element 42 extending in the vertical direction and the length of the portion of the element 42 extending in the left-right direction. For example, when the antenna 40 receives FM broadcast waves (76 MHz to 108 MHz), the wavelength λ in the air of the radio waves in the frequency band that the antenna 40 receives is as follows: , approximately 3.26m. The wavelength shortening rate k of the glass plate structure 20 is, for example, 0.64.

Note that the element 42 can form any pattern in the non-conductive region 20B, not only the L-shaped conductor pattern, as long as it can receive radio waves in a predetermined frequency band. For example, the conductor pattern of the element 42 may be a linear element having an open end on an extension line along the left edge 24, or the conductor pattern may be branched to have two or more open ends. Furthermore, at least a portion of the power feeding section 41 and the element 42 may be extended or placed not only on the non-conductive region 20B of the glass plate structure 20 but also on the resin plate 10 which is a dielectric material. Further, when the power feeding unit 41 and the element 42 are arranged on the resin plate 10, it does not matter whether the glass plate structure 20 has a non-conductive region 20B. For example, the glass plate structure 20 has a conductive region 20A and may not include the non-conductive region 20B.

The ground portion 43 is a conductor pattern formed in a rectangular shape, and is connected to the external conductor 2b of the transmission line 2 directly or via the connection line 2c. Note that the shape of the ground portion 43 may be other shapes such as a circle or another polygon. The ground portion 43 is located in the conductive region 20A of the glass plate structure 20, near the left edge 24 of the glass plate structure 20, and below the power feeding portion 41, but the arrangement is not limited thereto.

In a plan view of the first glass plate 51, the ground portion 43 sandwiches the second glass plate 52 and the intermediate film 53, overlaps the conductive film 54, and is capacitively coupled to the conductive film 54. According to this configuration, even if the window frame to which the glass plate structure 20 is attached is the resin plate 10, the ground can be taken from the conductive film 54 of the component of the glass plate structure 20. In the first embodiment, the internal conductor 2a of the transmission line 2 is connected to the power feeding part 41 of the antenna 40, and the external conductor 2b of the transmission line 2 is connected to the ground part 43 of the antenna 40, and capacitive coupling is established with the conductive film 54. By taking the ground from the ground portion 43, the decrease in the gain of the vehicle antenna 1 is suppressed.

As described above, the vehicle antenna 1 of the first embodiment includes the first glass plate 51 having the first main surface 51a and the second main surface 51b, and the conductive film 54 disposed on the second main surface 51b side. a frame-shaped resin plate 10 that overlaps the peripheral portion 21 of the glass plate structure 20 in a plan view of the first glass plate 51, a power supply section 41, and an element 42 connected to the power supply section 41. , and an antenna 40 having a ground portion 43, the glass plate structure 20 has a conductive region 20A including a conductive film 54 and a non-conductive region not including the conductive film 54 in a plan view of the first glass plate 51. 20B, the ground portion 43 is electrically connected to the conductive film 54, and the power feeding portion 41 and the element 42 are connected to at least one of the non-conductive region 20B and the resin plate 10, other than the conductive region 20A. Placed. According to this configuration, in the glass plate structure 20 that is attached to the frame-shaped resin plate 10 and includes the conductive film 54, the antenna 40 can receive radio waves in a predetermined frequency band with a desired gain.

Further, in the first embodiment, the non-conductive region 20B extends in a band shape with a predetermined width along the edge (upper edge 22) of the glass plate structure 20 when the first glass plate 51 is viewed from above. Element 42 is placed in non-conductive region 20B. According to this configuration, while adding a thermal/optical function to substantially the entire glass plate structure 20, the non-conductive By providing the region 20B, a decrease in the gain of the vehicle antenna 1 can be suppressed.

Further, the non-conductive region 20B is preferably formed with a width of 5 mm to 140 mm. Thereby, a sufficient space for arranging the element 42 can be secured. Furthermore, the element 42 extends substantially parallel to the edge of the non-conductive region 20B, and is disposed 5 mm or more from the boundary 20C between the conductive region 20A and the non-conductive region 20B in a plan view of the first glass plate 51. good. According to this configuration, the element 42 is less likely to be influenced by the conductive region 20A.

In the first embodiment, the length L of the element 42 is defined as follows: where λ is the wavelength in the air at the center frequency of the frequency band received by the antenna 40 and k is the wavelength shortening rate of the glass plate structure 20. It is preferable to satisfy 0.70×(1/4)×λ×k≦L≦1.30×(1/4)×λ×k. According to this configuration, the antenna characteristics of the vehicle antenna 1 can be improved.

Further, in the first embodiment, the glass plate structure 20 has an intermediate film 53 containing resin and a second glass plate 52 in this order on the second main surface 51b side of the first glass plate 51, and The plate 52 has a third main surface 52a on the interlayer film 53 side and a fourth main surface 52b on the opposite side to the interlayer film 53 side. The antenna 40 is arranged on the fourth main surface 52b of the second glass plate 52. By disposing the antenna 40 on the fourth main surface 52b (inner surface of the vehicle) of the second glass plate 52, the antenna 40 can be protected from the outside.

Further, in the first embodiment, the conductive film 54 has a sheet resistance of 5Ω/□ or less. According to this configuration, the conductive film 54 can sufficiently function as a ground for the antenna 40. Further, the conductive film 54 may be a heat ray reflective film disposed on the second main surface 51b of the first glass plate 51. According to this configuration, it is possible to effectively reflect heat rays contained in sunlight and the like that enter the inside of the vehicle.

Further, in the first embodiment, the non-conductive region 20B extends in the horizontal direction when the glass plate structure 20 is attached to a vehicle. Further, the non-conductive region 20B is tilted within a range of 0° to 75° with respect to the vertical direction when the glass plate structure 20 is attached to a vehicle. According to this configuration, vertically polarized waves such as FM broadcast waves and band III of the DAB standard can be effectively received.

[Second embodiment]
FIG. 4 is an exploded perspective view of a vehicle antenna 1 according to a second embodiment of the present invention. FIG. 5 is a sectional view of a vehicle antenna 1 according to a second embodiment of the present invention. In addition, in FIG. 4 and FIG. 5, the same reference numerals are attached to the same configurations as those in the above-described embodiment.

As shown in FIGS. 4 and 5, in the vehicle antenna 1 of the second embodiment, the interlayer film 53 includes a first interlayer film 53a and a second interlayer film 53b, and the conductive film 54 includes a first interlayer film 53a and a second interlayer film 53b. This embodiment differs from the embodiment described above in that it is disposed between the intermediate film 53a and the second intermediate film 53b. The conductive film 54 of the second embodiment is, for example, a conductor included in a light control film whose visible light transmittance can be controlled by applying an alternating current voltage. Although not shown in FIGS. 4 and 5, a harness for applying an AC voltage from the outside is arranged on the light control film so as to be connected to the glass plate structure 20. Although a light control film will be exemplified below, a film antenna or the like may be used as the conductive film 54 disposed between the first intermediate film 53a and the second intermediate film 53b.

The light control film consists of a pair of resin substrates, a pair of ITO (Indium Tin Oxide) provided on the main surface of each opposing resin substrate, a transparent conductive polymer, a laminated film of a metal layer and a dielectric layer, and silver. It has nanowires, a conductive film such as a silver or copper metal mesh, and a light control layer sandwiched between a pair of conductive films. The light control layer is a molecular layer of liquid crystal or the like having optical anisotropy. Examples of the molecular layer include polymer dispersed liquid crystal (PDLC), polymer network liquid crystal (PNLC), and guest-host liquid crystal. Alternatively, iodine or the like may be used as the molecule having optical anisotropy. The light management film may have a suspended particle device (SPD) that includes such a molecular layer.

In FIGS. 4 and 5, the conductive film 54 is shown as one layer for convenience, but in the case of a light control film, it refers to a pair of conductive films. Further, the first intermediate film 53a and the second intermediate film 53b are adhesive layers made of, for example, transparent polyvinyl butyral (PVB), ethylene vinyl acetate copolymer (EVA), cycloolefin polymer (COP), etc. It is arranged on the second main surface 51b of the glass plate 51 and the third main surface 52a of the second glass plate 52. The first intermediate film 53a and the second intermediate film 53b bond the first glass plate 51, the conductive film 54, and the second glass plate 52 to form a laminated glass plate structure 20. is forming.

Antenna 40 has a power feeding section 41, an element 42, and a grounding section 43. The power feeding section 41 and the element 42 are arranged in the non-conductive region 20B of the glass plate structure 20. Further, the ground portion 43 is arranged in the conductive region 20A of the glass plate structure 20. Also in the second embodiment, the internal conductor 2a of the transmission line 2 (not shown) is connected to the power feeding part 41 of the antenna 40, and the external conductor 2b of the transmission line 2 is connected to the ground part 43 of the antenna 40. Thereby, a decrease in the gain of the vehicle antenna 1 can be suppressed by connecting the conductive film 54 of the light control film to the ground through capacitive coupling.

As described above, in the vehicle antenna 1 of the second embodiment, the intermediate film 53 has the first intermediate film 53a and the second intermediate film 53b, and the conductive film 54 has the first intermediate film 53a and the second intermediate film 53b. It is arranged between the intermediate film 53b and the intermediate film 53b. The conductive film 54 is a conductor included in the light control film. According to this configuration, the antenna 40 can be grounded using the conductive film 54 included in the light control film while actively changing the visible light transmittance of the glass plate structure 20.

[Third embodiment]
FIG. 6 is an exploded perspective view of a vehicle antenna 1 according to a third embodiment of the present invention. FIG. 7 is a sectional view of a vehicle antenna 1 according to a third embodiment of the present invention. In addition, in FIG. 6 and FIG. 7, the same reference numerals are given to the same configurations as those in the above-described embodiment.

As shown in FIGS. 6 and 7, the vehicle antenna 1 of the third embodiment differs from the above-described embodiment in that the conductive film 54 is disposed on the third main surface 52a of the second glass plate 52. different. The glass plate structure 20 of the third embodiment includes an intermediate film 53, a conductive film 54, and a second glass plate 52 in this order on the second main surface 51b side of the first glass plate 51. The conductive film 54 may be a low-emission conductive film (Low-E (Low Emissivity) coat).

Here, low radiation refers to reducing heat transfer due to radiation. Low-emission films such as Low-E coating ensure heat insulation by suppressing heat transfer due to radiation. The low-emission film may be a general one, for example, a laminated film including a transparent dielectric film, an infrared reflective film, and a transparent dielectric film in this order. Typical transparent dielectric films are metal oxides and metal nitrides. Typical metal oxides include zinc oxide and tin oxide. A typical example of the infrared reflective film is a metal film. Silver (Ag) is typical of the metal film. Here, one or more infrared reflective films may be formed between the transparent dielectric films.

This conductive film 54 often has a sheet resistance higher than 5Ω/□, and has a characteristic that it is difficult to function as a ground for the antenna 40. Therefore, in the third embodiment, it is preferable to provide a conductive frame 54a having a lower resistance than the conductive film 54 on the outer periphery of the conductive region 20A when the first glass plate 51 is viewed from above. The conductive frame 54a is a frame-shaped conductor located on the third main surface 52a side of the second glass plate 52, and is arranged in the same layer as the conductive film 54 on the third main surface 52a side with respect to the second glass plate 52, for example. Alternatively, the conductive film 54 may be placed on the opposite side of the third main surface 52a of the second glass plate 52 (on the intermediate film 53 side).

The conductive frame 54a may be in contact with the third main surface 52a, or may be placed on the third main surface 52a side via a dielectric (not shown), or may be in contact with the conductive film 54. The conductive frame 54a has an inner edge along the outer edge of the conductive film 54 when the first glass plate 51 is viewed from above. The conductive frame 54a is made of, for example, a metal material such as copper or silver, but is not limited to these, and may be made of a transparent or translucent conductive material.

The upper limit of the sheet resistance of the conductive frame 54a should just be lower than the sheet resistance of the conductive film 54, for example, preferably 2Ω/□ or less, more preferably 1Ω/□ or less. In this way, the electrical resistances of the conductive frame 54a and the conductive film 54 can be compared using, for example, sheet resistance as an index. Note that the width of the conductive frame 54a can be designed as appropriate, and may be, for example, 1 mm to 20 mm, 2 mm to 15 mm, 3 mm to 10 mm, or 3 mm to 7 mm.

The antenna 40 has a power feeding part 41, an element 42, and a grounding part 43, and the power feeding part 41 and the element 42 are arranged in the non-conductive region 20B of the glass plate structure 20. Further, the ground portion 43 is the conductive region 20A of the glass plate structure 20, and is arranged to overlap the conductive frame 54a when the first glass plate 51 is viewed from above. Note that a grounding element may be extended from the grounding portion 43, and this grounding element may be arranged to overlap the conductive frame 54a when the first glass plate 51 is viewed from above. Also in the third embodiment, the internal conductor 2a of the transmission line 2 (not shown) is connected to the power feeding part 41 of the antenna 40, and the external conductor 2b of the transmission line 2 is connected to the ground part 43 of the antenna 40. By capacitively coupling the ground portion 43 with the conductive frame 54a and establishing a ground, a decrease in the gain of the vehicle antenna 1 can be suppressed.

As described above, in the vehicle antenna 1 of the third embodiment, the conductive film 54 is a low-emission film such as a Low-E coat with a sheet resistance higher than 5Ω/□, and when the first glass plate 51 is viewed from above, A conductive frame 54a having a lower resistance than the conductive film 54 is provided on the outer periphery of the conductive region 20A. In this way, since the conductive frame 54a has a lower electrical resistance than the conductive film 54, current can easily flow through the conductive frame 54a around the conductive film 54, so that the conductive frame 54a can sufficiently function as a ground. Therefore, even if the conductive film 54 with relatively high electrical resistance is used, the vehicle antenna 1 with high gain can be obtained.
In addition, when the light control film of 2nd Embodiment mentioned above uses the electrically conductive film 54 of high resistance, it may be provided with the electrically conductive frame 54a of low resistance similarly to 3rd Embodiment. In this case, the conductive frame 54a is attached to the second main surface 51b of the first glass plate 51, the third main surface 52a or the fourth main surface 52b of the second glass plate 52, so as not to short-circuit the power supply line of the light control film. Just place it. Note that the conductive frame 54a may be placed on the same surface as the light control film if it can be electrically isolated using an insulating sheet or the like, or if a frame can be provided around the conductive film 54 of the light control film.

[Fourth embodiment]
FIG. 8 is an exploded perspective view of a vehicle antenna 1 according to a fourth embodiment of the present invention. In addition, in FIG. 8, the same reference numerals are attached to the same configurations as those in the above-described embodiment.

As shown in FIG. 8, in the vehicle antenna 1 of the fourth embodiment, the glass plate structure 20 is not a laminated glass using two or more glass plates, but a single first glass plate 51 and a conductive glass plate 51. It differs from the embodiment described above in that it is formed with a film 54. In the fourth embodiment, a conductive film 54 is disposed on the second main surface 51b of the first glass plate 51. Further, in the fourth embodiment, the defogger 30 provided with the plurality of heater wires 32 is not provided in the glass plate structure 20. However, the conductive film 54 itself may form a planar conductive layer that can heat the glass plate structure 20 (without the heater wire 32) and function as a defogger.

In the fourth embodiment, a light shielding section 26, a power feeding section 41, and an element 42 are formed on the second main surface 51b of the first glass plate 51. In the fourth embodiment, the internal conductor 2a of the transmission line 2 is connected to the power feeding part 41 of the antenna 40, and the external conductor 2b of the transmission line 2 is directly connected to the ground part 43 (not shown) provided on the conductive film 54. There is. According to this configuration, by connecting the ground directly to the conductive film 54, a decrease in the gain of the vehicle antenna 1 can be suppressed.

Although the vehicle window glass according to the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and can be freely modified within the scope of the present invention. For example, some or all of the embodiments may be combined.

Hereinafter, the effects of the present invention will be made clearer by way of Examples. It should be noted that the present invention is not limited to the following examples, and can be implemented with appropriate modifications within the scope of the gist.

[First example]
FIG. 9 is a plan view of the vehicle antenna 1 according to the first embodiment of the present invention. In addition, in FIG. 9, the same reference numerals are given to the same configurations as those in the above-described embodiment.

The vehicle antenna 1 of the first embodiment includes a resin plate 10, a glass plate structure 20, and an antenna 40. Further, the glass plate structure 20 is a model of the glass plate structure 20 shown in FIG. 8 described above and includes the first glass plate 51 and the conductive film 54. That is, in the vehicle antenna 1 of the first embodiment, the conductive film 54 and the ground portion 43 of the antenna 40 are directly connected.

This vehicle antenna 1 has the following dimensions. The resin plate 10 has a horizontal dimension of 2,000 mm and a vertical dimension of 2,000 mm. The opening 11 of the resin plate 10 is arranged at the center of the resin plate 10, and its horizontal and vertical dimensions are each 1,000 mm. The width W of the non-conductive region 20B of the glass plate structure 20 was 50 mm, and the sheet resistance of the conductive film 54 was 1 Ω/□.

FIG. 10 is a graph showing simulation results of the antenna gain of the vehicle antenna 1 according to the first embodiment in the frequency band of FM broadcast waves. In FIG. 10 and FIGS. 11, 13 to 14, and 16 to 17, which will be described later, the horizontal axis represents frequency [MHz], and the vertical axis represents antenna gain [dB]. In FIG. 10 and FIGS. 11 and 13 to 14, which will be described later, "H" means "horizontal polarization" antenna gain, "V" means "vertical polarization" antenna gain, and "ABS ” means the total antenna gain of “horizontal polarization” and “vertical polarization.”

"La=550" in FIG. 10 means that in the simulation shown in FIG. 10, the length from the feed section 41 of the element 42 of the antenna 40 to the open end was set to 550 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 10, it was confirmed that the antenna gain of vertically polarized FM broadcast waves is -7.78 dB on average, which is a high value at a practical level. That is, it was confirmed that high sensitivity can be obtained by using the conductive film 54 as a ground for the antenna 40.

FIG. 11 is a graph showing simulation results of the antenna gain in Band III of the DAB standard of the vehicle antenna 1 according to the first embodiment.
"La=170" in FIG. 11 means that in the simulation shown in FIG. 11, the length from the feed section 41 of the element 42 of the antenna 40 to the open end was set to 170 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 11, it was confirmed that the vertically polarized antenna gain of Band III of the DAB standard is -5.65 dB on average, which is a high value at a practical level. That is, it was confirmed that high sensitivity can be obtained by using the conductive film 54 as a ground for the antenna 40.

[Second example]
FIG. 12 is a plan view of a vehicle antenna 1 according to a second embodiment of the present invention. In addition, in FIG. 12, the same reference numerals are given to the same components as in the embodiment described above.

The vehicle antenna 1 of the second embodiment includes a resin plate 10, a glass plate structure 20, and an antenna 40. Further, the glass plate structure 20 is a model of the glass plate structure 20 shown in FIG. 2 described above, which includes a conductive film 54 between the first glass plate 51 and the second glass plate 52. That is, in the vehicle antenna 1 of the second embodiment, the conductive film 54 and the ground portion 43 of the antenna 40 are electrically connected by capacitive coupling. Note that the second embodiment includes a grounding element 43a that extends downward from the grounding portion 43 and is capacitively coupled to the conductive film 54.

This vehicle antenna 1 has the following dimensions. The resin plate 10 has a horizontal dimension of 2,000 mm and a vertical dimension of 2,000 mm. The opening 11 of the resin plate 10 is arranged at the center of the resin plate 10, and its horizontal and vertical dimensions are each 1,000 mm. The width of the non-conductive region 20B of the glass plate structure 20 is 50 mm. The sheet resistance of the conductive film 54 is 1Ω/□.

FIG. 13 is a graph showing simulation results of the antenna gain of the vehicle antenna 1 in the frequency band of FM broadcast waves according to the second embodiment.
"La=550" in FIG. 13 means that in the simulation shown in FIG. 13, the length of the element 42 of the antenna 40 from the feed section 41 to the open end was set to 550 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 13, it was confirmed that the antenna gain of vertically polarized FM broadcast waves is -7.78 dB on average, which is a high value at a practical level. That is, it was confirmed that high antenna sensitivity could be obtained by using the conductive film 54 disposed within the laminated glass as a ground for the antenna 40.

FIG. 14 is a graph showing simulation results of the antenna gain in Band III of the DAB standard of the vehicle antenna 1 according to the second embodiment.
"La=180" in FIG. 14 means that in the simulation shown in FIG. 14, the length of the element 42 of the antenna 40 from the feed section 41 to the open end was set to 180 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 14, it was confirmed that the vertically polarized antenna gain of Band III of the DAB standard is -5.89 dB on average, which is a high value at a practical level. That is, it was confirmed that high antenna sensitivity could be obtained by using the conductive film 54 disposed within the laminated glass as a ground for the antenna 40.

[Third example]
FIG. 15 is a plan view of a vehicle antenna 1 according to a third embodiment of the present invention. In addition, in FIG. 15, the same reference numerals are attached to the same configurations as those in the above-described embodiment.

The vehicle antenna 1 of the third embodiment includes a resin plate 10, a glass plate structure 20, and an antenna 40. Further, the glass plate structure 20 is a model of the glass plate structure 20 shown in FIG. . That is, in the vehicle antenna 1 of the third embodiment, the conductive frame 54a having a lower resistance than the conductive film 54 and the ground portion 43 of the antenna 40 are directly connected.

This vehicle antenna 1 has the following dimensions. The resin plate 10 has a horizontal dimension of 2,000 mm and a vertical dimension of 2,000 mm. The opening 11 of the resin plate 10 is arranged at the center of the resin plate 10, and its horizontal and vertical dimensions are each 1,000 mm. The width of the non-conductive region 20B of the glass plate structure 20 is 50 mm. The sheet resistance of the conductive film 54 is 15Ω/□. The sheet resistance of the conductive frame 54a was 0Ω/□ (PEC: perfect electrical conductor), and the width of the conductive frame 54a was 10 mm.

FIG. 16 is a graph showing simulation results of vertically polarized antenna gain in the frequency band of FM broadcast waves of the vehicle antenna 1 according to the third embodiment. “w/oFrame” in FIG. 16 and FIG. 17 described later means the antenna gain of the comparative example “without the conductive frame 54a”, and “w/Frame” means the antenna of Example 3 “with the conductive frame 54a”. means gain.
"La=550" in FIG. 16 means that in the simulation shown in FIG. 16, the length from the feed section 41 of the element 42 of the antenna 40 to the open end was set to 550 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 16, it was confirmed that the antenna gain of the vertically polarized FM broadcast wave was -6.35 dB on average in the state "with the conductive frame 54a", which is a high value at a practical level. That is, if the high-resistance conductive film 54 is used as it is as a ground for the antenna 40, the sensitivity will decrease, but it was confirmed that the antenna sensitivity can be improved by surrounding the conductive film 54 with a low-resistance conductive frame 54a. .

FIG. 17 is a graph showing simulation results of vertically polarized antenna gain in band III of the DAB standard of the vehicle antenna 1 according to the third embodiment.
"La=170" in FIG. 17 means that in the simulation shown in FIG. 17, the length from the feed section 41 of the element 42 of the antenna 40 to the open end was set to 170 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 17, it was confirmed that the vertically polarized antenna gain of Band III of the DAB standard was -6.41 dB on average in the state "with the conductive frame 54a", which is a high value at a practical level. That is, if the high-resistance conductive film 54 is used as it is as a ground for the antenna 40, the sensitivity will decrease, but it was confirmed that the antenna sensitivity can be improved by surrounding the conductive film 54 with a low-resistance conductive frame 54a. .

The center frequency of the FM broadcast wave is 92 MHz, and the center wavelength (λ) is approximately 3,258 mm. Further, the center frequency of Band III of the DAB standard is 207 MHz, and the center wavelength (λ) is 1,448 mm. Further, assuming that the wavelength shortening rate (k) of the glass plate structure 20 is 0.64, the length L of the element 42 of the antenna 40 of the first to third embodiments is determined by the above-mentioned relational expression (1). and the range is set to a preferred length.
In this way, according to the first to third embodiments, it was possible to provide the vehicle antenna 1 that can receive radio waves in a predetermined frequency band with a desired gain.

[Fourth example]
In the fourth example, the antenna gain was measured when the sheet resistance of the conductive film 54 was changed in the model shown in FIG. 15 described above. Note that the sheet resistance of the conductive frame 54a is constant.

FIG. 18 is a graph showing simulation results of vertically polarized antenna gain in the frequency band of FM broadcast waves of the vehicle antenna 1 according to the fourth embodiment. In FIG. 18 and FIG. 19 described later, the horizontal axis represents the sheet resistance [Ω/□], and the vertical axis represents the average gain of vertical polarization [dB].
"La=550" in FIG. 18 means that in the simulation shown in FIG. 18, the length from the feed section 41 of the element 42 of the antenna 40 to the open end was set to 550 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 18, it was confirmed that the sheet resistance value at which the antenna gain of vertically polarized FM broadcast waves is reduced by 3 dB is 100 Ω/□. Therefore, when receiving radio waves in the frequency band of FM broadcast waves, it was confirmed that the sheet resistance of the conductive film 54 having the above-mentioned conductive frame 54a is preferably 100Ω/□ or less.

FIG. 19 is a graph showing simulation results of vertically polarized antenna gain in band III of the DAB standard of the vehicle antenna 1 according to the fourth example.
"La=170" in FIG. 19 means that in the simulation shown in FIG. 19, the length of the element 42 of the antenna 40 from the feed section 41 to the open end was set to 170 mm. La is adjusted according to the vertical polarization characteristics of the antenna 40. Referring to FIG. 19, it was confirmed that the sheet resistance value at which the vertically polarized antenna gain of band III of the DAB standard was reduced by 3 dB was 60 Ω/□. Therefore, it was confirmed that when receiving radio waves in band III of the DAB standard, the sheet resistance of the conductive film 54 having the conductive frame 54a described above is preferably 60Ω/□ or less.

In addition, it is possible to appropriately replace the components in the embodiments with well-known components without departing from the spirit of the present invention.

For example, as the conductive film 54, although a Low-E film, a heat ray reflective film, and a light control film are exemplified, a film heater may be used. A film heater includes, for example, a pair of bus bars that are placed between laminated glasses and supply current to both sides of a film-like conductive film.
Further, for example, in the third embodiment, the ground portion 43 is capacitively coupled to the conductive frame 54a surrounding the conductive film 54, but the ground portion 43 and the conductive frame 54a may be capacitively coupled.

1 Vehicle antenna 2 Transmission line 2a Inner conductor 2b Outer conductor 2c Connection line 10 Resin plate 10a Outer surface 10b Inner surface 11 Opening 12 Accommodation groove 13 Adhesive 20 Glass plate structure 20A Conductive area 20B Non-conductive area 20C Boundary 21 Peripheral area 22 Upper edge 22a Upper edge 23 Lower edge 24 Left edge 25 Right edge 26 Light shielding section 30 Defogger 31a First bus bar 31b Second bus bar 32 Heater wire 40 Antenna 41 Power feeding section 42 Element 43 Earth section 43a Grounding element 51 First glass plate 51a First main surface 51b Second main surface 52 Second glass plate 52a Third main surface 52b Fourth main surface 53 Intermediate film 53a First interlayer film 53b Second interlayer film 54 Conductive film 54a Conductive frame

Claims (21)

a first glass plate having a first main surface and a second main surface opposite to the first main surface, and a glass plate structure including a conductive film disposed on the second main surface side;
in a plan view of the first glass plate, a frame-shaped resin plate that overlaps with a peripheral portion of the glass plate structure;
comprising a power feeding section, an element connected to the power feeding section, and an antenna having a grounding section,
The glass plate structure has a conductive region including the conductive film in a plan view of the first glass plate,
The ground portion is electrically connected to the conductive film,
A vehicle antenna, wherein the power feeding section and the element are arranged outside the conductive region. The glass plate structure has a non-conductive region that does not include the conductive film in a plan view of the first glass plate,
The vehicle antenna according to claim 1, wherein the power feeding section and the element are arranged in at least one of the non-conductive region and the resin plate. The non-conductive region extends in a band shape of a predetermined width along the edge of the glass plate structure in a plan view of the first glass plate,
The vehicle antenna according to claim 2, wherein the element is arranged in the non-conductive region. The vehicle antenna according to claim 3, wherein the non-conductive region is formed with the predetermined width of 5 mm to 140 mm. 4 . The element extends substantially parallel to an edge of the non-conductive region, and is disposed at a distance of 5 mm or more from a boundary between the conductive region and the non-conductive region in a plan view of the first glass plate. The vehicle antenna described in . The glass plate structure has an intermediate film containing a resin and a second glass plate in this order on the second main surface side of the first glass plate,
The vehicle antenna according to claim 1, wherein the second glass plate has a third main surface on the interlayer film side and a fourth main surface on the opposite side to the interlayer film side. The vehicle antenna according to claim 6, wherein the conductive film is arranged on at least one of the second main surface and the third main surface. The vehicle antenna according to claim 6, wherein the antenna is arranged on the fourth main surface. The vehicle antenna according to claim 6, wherein the antenna is arranged on the second main surface or the third main surface. The vehicle antenna according to claim 9, wherein the conductive film is arranged on a main surface different from the antenna, out of the second main surface or the third main surface. The intermediate film includes a first intermediate film and a second intermediate film,
The vehicle antenna according to claim 6, wherein the conductive film is arranged between the first intermediate film and the second intermediate film. The vehicle antenna according to claim 11, wherein the conductive film is a conductor included in a light control film. The length L of the element is defined as λ is the wavelength in the air at the center frequency of the frequency band received by the antenna, and k is the wavelength shortening rate of the glass plate structure.
0.70×(1/4)×λ×k ≦ L ≦ 1.30×(1/4)×λ×k
The vehicle antenna according to any one of claims 1 to 12, which satisfies the following. The vehicle antenna according to any one of claims 1 to 12, wherein the conductive film has a sheet resistance of 5Ω/□ or less. The vehicle antenna according to claim 14, wherein the conductive film includes a heat ray reflective film. The conductive film has a sheet resistance higher than 5Ω/□,
The vehicle antenna according to any one of claims 1 to 12, further comprising a conductive frame having a lower resistance than the conductive film on the outer periphery of the conductive region in a plan view of the first glass plate. The vehicle antenna according to claim 16, wherein the conductive film includes a conductor for a low-emission film. The vehicle antenna according to any one of claims 2 to 5, wherein the non-conductive region extends horizontally when the glass plate structure is attached to a vehicle. The vehicle antenna according to any one of claims 2 to 5, wherein the non-conductive region is inclined in a range of 0° to 75° with respect to the vertical direction when the glass plate structure is attached to a vehicle. . The vehicle antenna according to any one of claims 1 to 12, wherein the antenna receives radio waves of at least one of a VHF band and a UHF band frequency. The vehicle antenna according to any one of claims 1 to 12, wherein the glass plate structure is a rear glass.

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