Automotive glass antenna

Abstract

To provide an antenna which secures an antenna length in a horizontal direction and a vertical direction without expanding an existing light shielding film and blocking a driver's visual field.SOLUTION: A glass antenna is provided at a windshield 3 of a vehicle and includes: a first element 12 connected to a first power supply terminal 11; and a second element 14 connected to a second power supply terminal 13 and at least partially extending in a vehicle width direction. The first element 12 includes: a first portion 12B which extends in the vehicle width direction at least partially overlapping with a first protruding part 42 of a light shielding film; and a second portion 12C connected to the first portion 12B and extending downward along a right side 42B of the first protruding part 42.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an antenna that is disposed on the window glass of an automobile and receives broadcasts, that is, a so-called glass antenna. [Background technology]

[0002] Glass antennas are often installed on the rear window, particularly above the rear defogger heating wire. With the recent spread of rearview cameras, the area of rear windows has tended to become smaller. Accordingly, the placement of the heating wire and glass antenna has been reconsidered, but because it is impossible to eliminate the rear defogger heating wire, the space available for installing the glass antenna has become smaller. Therefore, glass antennas are sometimes installed on the front window (see, for example, Patent Document 1).

[0003] When a glass antenna is installed on the front windshield, it needs to be positioned so as not to obstruct the driver's field of view. The glass antenna described in Patent Document 1 is expected to not obstruct the driver's field of view by overlapping the antenna with the light-shielding film as much as possible and by locating the portion of the antenna outside the light-shielding film as close to the film as possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2020-123922 Summary of the Invention [Problem to be solved by the invention]

[0005] From the perspective of antenna reception sensitivity, radio waves are waves (polarized waves) with a fixed direction in which the electric field oscillates as they propagate through space, and in order to receive radio waves stably, it is necessary to extend the glass antenna as far as possible in line with the direction of polarization.

[0006] The glass antenna of Patent Document 1 has a vertically extending portion and a horizontally extending portion, and is intended to receive the vertical polarization DAB (Digital Audio Broadcasting) band (170 - 240 MHz) and the horizontal polarization DTV (Digital Television) band (470 - 710 MHz). However, since the antenna is overlapped with a light-shielding film having a small vertical width and the exposed part is also arranged as close to the light-shielding film as possible, it is difficult to secure the vertical length, and the reception sensitivity for vertical polarization is not good. To stably receive vertical polarization, it is necessary to extend the glass antenna as much as possible in the vertical direction.

[0007] When the antenna is lengthened, a part of the antenna will be located outside the light-shielding film, increasing the possibility of entering the driver's field of view and being unfavorable in terms of appearance. Expanding the light-shielding film to hide this antenna will narrow the forward field of view. Therefore, there is room for consideration in the arrangement method of the glass antenna in order to secure the length in both the horizontal and vertical directions without expanding the light-shielding film and without disturbing the driver's field of view.

Means for Solving the Problem

[0008] Regarding the above problem, the inventor of the present case first focused on the left and right sides of the convex portion that is generally located in front of the rearview mirror and protrudes downward from the periphery of the light-shielding film at the upper center of the front window. Through intensive research, it was found that by arranging the antenna along the left and right sides of this convex portion, the vertical length can be secured and the antenna can be made inconspicuous.

[0009] Define the shape and elongation limit of the antenna placement location The present invention embodying this finding has a front window of an automobile with a light-shielding film, and the light-shielding film is composed of a peripheral portion along the periphery of the front window and a convex portion that continuously protrudes downward and forward from the peripheral portion, and a first power supply terminal provided on the peripheral portion or the convex portion, the first power supply terminal is composed of a convex-shaped convex portion that continuously protrudes downward and forward from the peripheral portion, and a first power supply terminal provided on the peripheral portion or the convex portion, the first power supply terminal a first element connected to the child, a second power supply terminal provided at the peripheral portion or the convex portion, and a second element that is connected to the second power supply terminal and at least a part of which extends in the vehicle width direction at the peripheral portion is an automotive glass antenna. At least a part of the first element of this glass antenna overlaps the convex portion and extends in the vehicle width direction, a first part, and is connected to the first part, and has a second part that extends downward along the convex portion and has a third part that is connected to the second part of the first element and extends in the vehicle width direction along the convex portion. According to the present invention configured as described above, the first element ensures a vertical length without being conspicuous by the second part extending downward along the convex portion. On the other hand, the second element

[0010] ensures a horizontal length without being conspicuous by extending in the vehicle width direction at the peripheral portion. Thereby, without expanding the existing light-shielding film and without obstructing the driver's field of view, the length of the glass antenna is ensured in both the vertical direction and the horizontal direction, and the reception sensitivities of both vertical polarization and horizontal polarization can be improved. Without making the glass antenna conspicuous, the horizontal length can be extended, and the reception sensitivity of the horizontal polarization can be further improved. Furthermore, preferably in the present invention, the second power supply terminal is disposed on the convex portion, the second element is connected to the second power supply terminal, has a fourth part that extends upward, and is connected to the fourth part and disposed on the peripheral portion and extends in the vehicle width direction. By configuring in this way, the fifth part can be brought closer to the peripheral edge of the front window, the width of the peripheral edge of the light-shielding film can be shortened, and a wider forward field of view of the driver can be ensured. Furthermore, preferably in the present invention, the second power supply terminal is disposed on the convex portion, the second element is connected to the second power supply terminal, has a fourth part that extends upward, and is connected to the fourth part and disposed on the peripheral portion and extends in the vehicle width direction. By configuring in this way, the fifth part can be brought closer to the peripheral edge of the front window, the width of the peripheral edge of the light-shielding film can be shortened, and a wider forward field of view of the driver can be ensured. Thereby, without expanding the existing light-shielding film and without obstructing the driver's field of view, the length of the glass antenna is ensured in both the vertical direction and the horizontal direction, and the reception sensitivities of both vertical polarization and horizontal polarization can be improved. Without making the glass antenna conspicuous, the horizontal length can be extended, and the reception sensitivity of the horizontal polarization can be further improved. Thereby, without expanding the existing light-shielding film and without obstructing the driver's field of view, the length of the glass antenna is ensured in both the vertical direction and the horizontal direction, and the reception sensitivities of both vertical polarization and horizontal polarization can be improved. Without making the glass antenna conspicuous, the horizontal length can be extended, and the reception sensitivity of the horizontal polarization can be further improved. Furthermore, preferably in the present invention, the second power supply terminal is disposed on the convex portion, the second element is connected to the second power supply terminal, has a fourth part that extends upward, and is connected to the fourth part and disposed on the peripheral portion and extends in the vehicle width direction. By configuring in this way, the fifth part can be brought closer to the peripheral edge of the front window, the width of the peripheral edge of the light-shielding film can be shortened, and a wider forward field of view of the driver can be ensured.

[0012] Furthermore, preferably in the present invention, the second power supply terminal is disposed on the convex portion, the second element is connected to the second power supply terminal, has a fourth part that extends upward, and is connected to the fourth part and disposed on the peripheral portion and extends in the vehicle width direction. By configuring in this way, the fifth part can be brought closer to the peripheral edge of the front window, the width of the peripheral edge of the light-shielding film can be shortened, and a wider forward field of view of the driver can be ensured.

Effects of the Invention

[0013] As described above, according to the glass antenna for automobiles of the present invention, without expanding the existing light-shielding film and without obstructing the driver's view, the length of the glass antenna can be ensured in both the vertical direction and the horizontal direction, and the reception sensitivities for both vertical polarization and horizontal polarization can be improved.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0015] As shown in FIG. 1, the glass antenna 1 is provided at the upper part of the front window 3 of the automobile 2. The glass antenna 1 partially overlaps with a light-shielding film described later, and the overlapping part is difficult to see. The front window 3 is attached to the vehicle body opening of the automobile 2 with an adhesive. The glass antenna 1 is provided at the upper center of the front window 3 so as to receive radio waves in the DAB band of 170 - 240 MHz and the DTV band of 470 - 710 MHz among digital broadcasts.

[0016] The following will be described with reference to FIG. 2, which is a view extracted from the perspective view of the vehicle 2 to show the front window. A light-shielding film 4 is provided around the front window 3. The light-shielding film 4 is formed by dot-like application of a paint containing ceramic on the inside of the vehicle. The light-shielding film 4 is composed of a peripheral edge portion 41, a first convex portion 42, and a second convex portion 43. The first convex portion 42 is continuous with the peripheral edge portion 41 at the upper center of the front window and is located downward and forward of the vehicle 2 from it. The second convex portion 43 is continuous with the first convex portion 42 and is located downward and forward of the vehicle 2 from it.

[0017] The peripheral portion 41 of the light-shielding film 4 is disposed at the peripheral portion of the front window 3. And the peripheral portion 41 includes an upper edge portion 41A extending from the upper edge of the front window to its left and right ends along the upper edge, a lower edge portion 41B extending along the lower edge of the front window, a right edge portion 41C connecting the upper edge portion 41A and the lower edge portion 41B along the right edge of the front window, and a left edge portion 41D along the left edge.

[0018] As shown in FIG. 2, the first convex portion 42 is symmetric with respect to the center line in the vehicle width direction of the front window 3, is continuous from the upper edge portion 41A of the peripheral portion 41, and is located in front of the vehicle with respect to the upper edge portion 41A. In FIG. 3, it is located downward on the paper surface. And as shown in FIG. 3, the first convex portion 42 is composed of an upper side 42A, a right side 42B, and a lower side 42C. The upper side 42A is an imaginary line obtained by extending the lower side 41A1 of the upper edge portion 41A toward the center in the vehicle width direction. The right side 42B obliquely extends from the end point of the lower side 41A1 of the upper edge portion 41A toward the center and downward in the vehicle width direction. The lower side 42C extends in the vehicle width direction from the lower end of the right side 42B.

[0019] As shown in FIG. 2, the second convex portion 43 is symmetric with respect to the center line in the vehicle width direction of the front window 3, is continuous from the first convex portion 42, and is located in front of the first convex portion 42. In FIG. 3, it is located downward on the paper surface. And as shown in FIG. 3, the second convex portion 43 is composed of an upper side 43A, a right side 43B, and a lower side 43C. The upper side 43A is an imaginary line obtained by extending the lower side 42C of the first convex portion toward the center in the vehicle width direction. The right side 43B obliquely extends from the end point of the lower side 42C of the first convex portion toward the center and downward in the vehicle width direction. The lower side 43C extends in the vehicle width direction from the lower end of the right side 43B.

[0020] As shown in FIG. 3, a part of the glass antenna 1 overlaps with the upper edge portion 41A of the peripheral portion 41 and the first convex portion 42. And the glass antenna 1 is composed of a first power supply terminal 11, a first element 12 extending from it, a second power supply terminal 13, and a second element 14 extending from it.

[0021] The first power supply terminal 11 and the second power supply terminal 13 are connected to a receiver via a power supply terminal with an amplifier (not shown) and a coaxial cable. Radio waves propagating in the atmosphere induce an alternating current inside the first element and the second element, and the current is amplified by the power supply terminal with an amplifier and transmitted from the power supply terminals 11 and 13. These power supply terminals are arranged in the first convex portion 42 so as not to be conspicuous.

[0022] The first element 12 and the second element 14 are set to lengths that are increased or decreased within a predetermined range with respect to a length obtained by multiplying the shortening rate α of glass by 1 / 4 of the first wavelength, which is the wavelength of the center frequency (205 MHz) of the DAB band lower than the DTV band. The predetermined range is set so that predetermined reception sensitivities in the DAB band and the DTV band can obtain an average reception sensitivity of -10 dB or more, for example, in comparison with a dipole antenna. Specifically, the first element may be in the range of 250 to 270 mm, and 255 mm is most desirable. The second element may be in the range of 230 to 290 mm, and 260 mm is most desirable.

[0023] As shown in FIG. 3, the first element 12 is composed of a first power supply terminal connection portion 12A extending downward from the first power supply terminal 11, a first portion 12B extending from the lower end of the first power supply terminal connection portion 12A to the right side in the vehicle width direction, a second portion 12C extending downward from the right end of the first portion 12B, and a third portion 12D extending from the lower end of the second portion 12C to the left side in the vehicle width direction, forming a substantially U-shaped shape. The length of the first power supply terminal connection portion 12A is 15 mm. The length of the first portion 12B is set to 60 to 65 mm, and 63 mm is most desirable. The length of the second portion 12C may be in the range of 95 to 105 mm, and 98 mm is most desirable. The length of the third portion 12D may be in the range of 75 to 85 mm, and 79 mm is most desirable.

[0024] The first element 12 is positioned such that a part of it overlaps with the first convex portion 42 of the light-shielding film 4. The first power supply terminal connection portion 12A of the first element 12 is positioned overlapping the first convex portion 42. A part of the first portion 12B overlaps with the first convex portion 42, and its right end is positioned outside the first convex portion. It is desirable that the distance between the right end of the first portion 12B and the right side 42B of the first convex portion 42 is 5 mm or less. The second portion 12C is positioned outside the first convex portion 42 and along its right side 42B. It is desirable that the distance between the second portion 12C and the right side 42B of the first convex portion 42 is 5 mm or less. The third portion 12D is positioned outside the first convex portion 42 and along its lower side 42C. It is desirable that the distance between the third portion 12D and the lower side 42C of the first convex portion 42 is 5 mm or less.

[0025] The second element 14 is composed of a fourth portion 14A extending upward from the second power supply terminal 13 and a fifth portion 14B extending from the upper end of the fourth portion 14A along both sides in the vehicle width direction along the upper edge of the front window 3, forming a T-shaped configuration. The length of the fourth portion 14A of the second element 14 may be 25 mm or less, and 20 mm is most desirable. The length of the fifth portion 14B may be in the range of 230 to 270 mm, and 240 mm is most desirable. The second element 14 is positioned overlapping the upper edge portion 41A of the light-shielding film 4. The fourth portion 14A of the second element 14 is positioned at a distance of 5 to 10 mm from the flange 5 of the vehicle 2.

[0026] Thus, according to the automotive glass antenna of the embodiment of the present invention, the first portion 12B of the first element 12 of the glass antenna 1 can improve the reception sensitivity of DTV radio waves with horizontal polarization without making the glass antenna 1 conspicuous by overlapping most of it with the first convex portion 42 of the light-shielding film 4. The second portion 12C is near the right side 42B of the first convex portion 42 and extends along the right side 42B, so that the reception sensitivity of DAB radio waves with vertical polarization can be improved without making the glass antenna 1 conspicuous. The third portion 12D is near the lower side 42C of the first convex portion 42 and extends along the lower side 42C, so that the reception sensitivity of DTV radio waves with horizontal polarization can be improved without making the glass antenna 1 conspicuous. Further, the fifth portion 14B of the second element 14 overlaps the upper edge portion 41A of the light-shielding film 4 and extends along the upper edge of the front window 3, so that the antenna length required for receiving DAB radio waves can be ensured without making the glass antenna 1 conspicuous. As described above, the automotive glass antenna of the embodiment can secure the antenna length both in the horizontal direction and in the vertical direction without expanding the existing light-shielding film and without obstructing the driver's view.

[0027] Thus, since a part of the automotive glass antenna 1 of the embodiment is overlapped with the light-shielding film 4 and arranged at a position that does not obstruct the driver's view, the glass antenna 1 can also be used in a right-hand drive vehicle. In the case of a right-hand drive vehicle, the glass antenna 1 may be arranged in a position symmetric about the center in the vehicle width direction of the front window 3 and reversed left and right so as not to obstruct the driver's view even more.

Explanation of Reference Numerals

[0028] 1 Glass antenna 2 Vehicle 3 Front window 4 Light-shielding film 11 First power supply terminal 12 First element 12B First portion 12C Second portion 12D Third portion 13 Second power supply terminal 14 Second element 14A Fourth part 14B Fifth part 41A Upper edge 41B Lower edge 41C Right edge 41B Left edge 42 First convex part 43 Second convex part

Claims

1. A glass antenna provided on the front window of an automobile, wherein the front window has a light-shielding film, and the light-shielding film is composed of an upper edge portion, a right edge portion, a lower edge portion, a left edge portion extending along the periphery of the front window, and a convex portion that continuously protrudes downward and forward from the upper edge portion at the upper central part of the front window. The glass antenna has a first power supply terminal provided on the upper edge portion or the convex portion, a first element connected to the first power supply terminal, a second power supply terminal provided on the upper edge portion or the convex portion, and a second element connected to the second power supply terminal and at least a part of which extends in the vehicle width direction at the upper edge portion. The first element has a first part that at least partially overlaps the convex portion and extends in the vehicle width direction, and a second part connected to the first part and extending downward along the periphery of the convex portion. The first element is connected to the second part and has a third part extending in the vehicle width direction along the convex portion. The glass antenna is characterized by this.

2. The glass antenna according to claim 1, wherein the second power supply terminal is disposed on the convex portion, the second element is connected to the second power supply terminal, has a fourth part extending upward, and a fifth part connected to the fourth part and disposed on the upper edge portion and extending in the vehicle width direction.

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