Vehicle Rear Monitoring Device with Antenna

Abstract

An antenna-equipped vehicle rear monitoring device 200 comprises: an image capturing device that captures an image to a rear of a vehicle; a display device that displays an image from the image capturing device in a front of the vehicle; and a dielectric substrate attached to a rear part of the vehicle. A conductor is provided on the dielectric substrate, and the conductor is an antenna that receives radio waves in a predetermined frequency band. A main surface of the dielectric substrate has unheated areas 1a, 1b, 1c, and 1d.

Description

Technical Field

[0001] The present invention relates to a vehicle rear monitoring device with an antenna.

Background Art

[0002] In recent years, instead of door mirrors, rearview mirrors, etc. for a driver to check (visually recognize) the surrounding situation of a vehicle during driving, automobiles equipped with electronic mirrors that allow a driver to visually recognize an outside-vehicle image obtained by an imaging means such as a CCD (charge-coupled device) camera have begun to spread (for example, Patent Document 1). Further, the electronic image thus obtained is useful for ensuring safety during the running of a vehicle. Therefore, there have been developed an electronic mirror device that operates so as to automatically project an image of the rear of the vehicle according to the degree of brightness outside the vehicle (for example, Patent Document 2), an electronic mirror device that detects a following vehicle approaching the vehicle and notifies the driver (for example, Patent Document 3), and the like. Thus, various systems for improving the safety of a vehicle by using an electronic mirror have been disclosed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, on the rear glass of a vehicle, a heating wire called a defroster or a transparent conductive film that can be heated is usually used to reduce fogging of the glass. However, when the technology described above enables the driver to view the situation behind the vehicle, the need for the driver to check the situation behind the vehicle through the rear glass is reduced. That is, even when the rear view of the vehicle through the rear glass is blocked, an external image recognition system that can secure the rear view of the vehicle without using a heating wire or the like can be established. In addition, conventionally, in addition to the defroster, an antenna capable of receiving broadcast waves such as AM, FM, DAB, and DTV is wired to the rear glass. These antennas are arranged in areas other than the area that requires the function of a defroster within the entire rear glass. For this reason, there has been a problem that there is a limit to the area where the antenna can be arranged.

[0005] The present invention has been made in view of the above, and an object thereof is to obtain a vehicle rear monitoring device with an antenna that can expand the arrangement area of the antenna attached to the rear glass in particular.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a vehicle rear monitoring device with an antenna according to the present invention includes an imaging device that images the rear of the vehicle, a display device that displays an image from the imaging device in front of the vehicle, and a dielectric substrate attached to the rear of the vehicle. The dielectric substrate has a conductor thereon, and the conductor is an antenna that receives radio waves in a predetermined frequency band. The main surface of the dielectric substrate is a non-heating region.

Effects of the Invention

[0007] According to the vehicle rear monitoring device with an antenna of the present invention, there is an effect that the arrangement area of the antenna attached to the rear glass in particular can be expanded.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

[0009] Hereinafter, an antenna-equipped vehicle rear monitoring device according to an embodiment of the present invention will be described in detail with reference to the drawings. In each embodiment, a deviation within a range that does not impair the effects of the present invention is allowed in directions such as parallel, perpendicular, horizontal, vertical, up and down, left and right. Also, the X-axis direction and the Y-axis direction represent directions parallel to the X-axis and the Y-axis, respectively. The X-axis direction and the Y-axis direction are perpendicular to each other. The XY plane represents a virtual plane parallel to the X-axis direction and the Y-axis direction. In FIGS. 2 and later, in the X-axis direction, the direction indicated by the arrow is defined as the plus X-axis direction, and the direction opposite to this direction is defined as the minus X-axis direction. In the Y-axis direction, the direction indicated by the arrow is defined as the plus Y-axis direction, and the direction opposite to this direction is defined as the minus Y-axis direction.

[0010] FIG. 1 is a diagram showing a configuration example of an antenna-equipped vehicle rear monitoring device 200 according to an embodiment of the present invention. The antenna-equipped vehicle rear monitoring device 200 includes a plurality of electronic mirrors 10, 11, 30 which are imaging devices for imaging the rear RD of the vehicle 100, a display device 20 for displaying an image from the imaging device in the front FD of the vehicle 100, and a dielectric substrate 102 attached to the rear portion 101 of the vehicle.

[0011] The electronic mirrors 10 and 11 are side mirrors with built-in cameras having imaging elements such as CCD or CMOS (Complementary Metal Oxide - Semiconductor). The electronic mirror 30 is a rearview mirror provided at the center in the vehicle width direction at a position near the rear part 101 of the vehicle 100 and has a built-in camera having an imaging element such as CCD or CMOS. Incidentally, the electronic mirror 30 is preferably attached above or below the dielectric substrate 102. Thereby, it is possible to prevent obstruction of the driver's field of view by the electronic mirror 30. The display device 20 is, for example, a liquid crystal display. Note that the details of the plurality of electronic mirrors 10, 11, 30 and the display device 20 are disclosed in, for example, Patent Document 1, etc., and thus the description is omitted.

[0012] The dielectric substrate 102 is, for example, a transparent or translucent plate-shaped dielectric, but may also be an opaque plate-shaped dielectric. The dielectric substrate 102 is applied to, for example, the rear windshield of an automobile. In the present embodiment, an example in which the dielectric substrate 102 is applied to the rear windshield will be described. Note that the dielectric substrate 102 is not limited to glass and may be, for example, a transparent, translucent or opaque resin.

[0013] Next, the configuration of the dielectric substrate 102 will be described with reference to FIG. 2. FIG. 2 is an enlarged view of the dielectric substrate 102 in a plan view looking from the inside of the vehicle 100 toward the rear RD of the vehicle 100. After FIG. 2, the X-axis direction is equal to the left - right direction (lateral direction) of the vehicle 100, that is, the vehicle width direction of the vehicle 100, or a substantially horizontal direction. The substantially horizontal direction includes a direction parallel to a line segment forming an angle of, for example, 0° to ±15° with respect to a horizontal plane orthogonal to the vertical direction. The Y-axis direction is equal to the up - down direction (longitudinal direction) of the vehicle 100, or a substantially vertical direction. The substantially vertical direction includes a direction parallel to a line segment forming an angle of, for example, 0° to ±15° with respect to a horizontal plane orthogonal to the vertical direction.

[0014] The dielectric substrate 102 is provided in the opening 103 of the vehicle 100. In FIG. 2, the opening 103 of the vehicle 100 is, for example, a space surrounded by the peripheral edge portion 104a of a flange 104 (metal body) provided on the vehicle 100. A part of the upper side portion 103a within the entire opening 103 of the vehicle 100 is equal to the peripheral edge portion 104a of the flange 104 provided on the roof (ceiling) of the vehicle 100.

[0015] Also, the opening 103 of the vehicle 100 is not limited to the space surrounded by the peripheral edge portion 104a of the flange 104 (metal body). For example, the dielectric substrate 102 may be a rear glass for an automobile or a rear glass for a back door. That is, the rear glass for the back door of a hatchback vehicle may, for example, be configured to be sandwiched between a resin inner panel (not shown) and a resin outer panel (not shown). Therefore, not limited to the space surrounded by the peripheral edge portion 104a of the flange 104, including the case of using such a back door, the opening 103 of the vehicle 100 can be defined as a region where the rear glass can be visually recognized in the vehicle 100. Note that the rear glass for an automobile is, for example, the rear glass of a sedan-type vehicle 100, but is not limited thereto, and any vehicle 100 with a metal body frame around the glass is acceptable. Also, the back door is not limited to being for a hatchback vehicle, and as long as it has the above-described configuration, it may be provided on vehicles other than hatchback vehicles.

[0016] The main surface of the dielectric substrate 102 is a non-heating region, and an antenna is provided in the non-heating region (main surface). Details of the non-heating region will be described later.

[0017] Examples of the antenna include an antenna for AM broadcast waves, an antenna for FM broadcast waves, an antenna for DAB (Digital Audio Broadcast) broadcast waves, an antenna for terrestrial digital television (DTV) broadcast waves, an antenna for remote keyless entry (RKE), and the like.

[0018] In the figure, "DAB1" and "DAB2" are, respectively, an antenna for receiving DAB Band III broadcast waves in the frequency band of, for example, 174 MHz to 240 MHz, and an antenna for receiving L-Band broadcast waves in the frequency band of 1452 MHz to 1492 MHz. "DTV1" and "DTV2" are, respectively, an antenna for receiving DTV broadcast waves in the frequency band of, for example, 473 to 803 MHz, and an antenna for receiving DTV broadcast waves in the frequency band of 90 to 770 MHz. "FM1" and "FM2" are antennas for receiving FM broadcast waves in the frequency band of 76 MHz to 108 MHz. "AM" is an antenna for receiving AM broadcast waves. Although seven types of antennas are illustrated in FIG. 2, any one of the antennas may be provided in the non-heating region of the dielectric substrate 102. FIG. 2 illustrates elements (conductors), feeding electrodes, ground electrodes, etc. that constitute these antennas provided in the non-heating region.

[0019] Next, with reference to FIG. 3, a specific example of the non-heating region and the antenna gain will be described. FIG. 3 is a diagram for explaining the antenna and the antenna gain provided in the non-heating region. As shown in FIG. 3, for example, four non-heating regions 1a to 1d are provided on the dielectric substrate 102.

[0020] The non-heating region 1a is a region near the upper side portion 103a and the left side portion 103d inside the opening 103 of the vehicle 100 (that is, near the plus Y-axis direction and the minus X-axis direction inside the peripheral edge portion 104a of the flange 104 shown in FIG. 2). In the non-heating region 1a, at least one of, for example, the "DAB1" antenna and the "DTV1" antenna is provided. Note that an antenna capable of receiving both DAB and DTV bands, a "DAB1 / DTV1" antenna, may be provided in the non-heating region 1a.

[0021] The non-heating area 1b is an area near the upper side portion 103a and the right side portion 103c within the opening 103 of the vehicle 100 (that is, near the plus Y-axis direction and the plus X-axis direction within the peripheral edge portion 104a of the flange 104 shown in FIG. 2). At least one of, for example, the "DAB2" antenna and the "DTV2" antenna is provided in the non-heating area 1b. Note that an antenna capable of receiving both DAB and DTV bands, a "DAB2 / DTV2" antenna, may be provided in the non-heating area 1b.

[0022] The non-heating area 1c is an area near the lower side portion 103b and the left side portion 103d within the opening 103 of the vehicle 100 (that is, near the minus Y-axis direction and the minus X-axis direction within the peripheral edge portion 104a of the flange 104 shown in FIG. 2). At least one of the "AM" antenna and the "FM1" antenna is provided in the non-heating area 1c. Note that an antenna capable of receiving both AM and FM bands, an "AM / FM1" antenna, may be provided in the non-heating area 1c.

[0023] The non-heating area 1d is an area near the lower side portion 103b and the right side portion 103c within the opening 103 of the vehicle 100 (that is, near the minus Y-axis direction and the plus X-axis direction within the peripheral edge portion 104a of the flange 104 shown in FIG. 2). An antenna capable of receiving, for example, the FM band, an "FM2" antenna, is provided in the non-heating area 1d.

[0024] Hereinafter, when the non-heating areas 1a, 1b, 1c, and 1d are not distinguished, they are simply referred to as the "non-heating area 1".

[0025] The results of measuring the gains of these antennas (antenna gains) are as follows. Note that these are data in a state without a defroster (see Table 1).

[0026]

Table 1

[0027] Note that the non-heating area 1 is preferably provided at a position near the peripheral edge 104a of the flange 104 within the opening 103 of the vehicle 100. Thereby, when the dielectric substrate 102 is a transparent rear glass, for example, when driving on a sunny day, even if the rear glass is not fogged, the obstruction of the field of view due to the antenna pattern can be reduced. Next, with reference to FIG. 4, a specific example of the non-heating area 1 provided at a position near the peripheral edge 104a of the flange 104 will be described. FIG. 4 is a diagram for explaining the non-heating area 1 provided at a position near the peripheral edge 104a of the flange 104.

[0028] L1 represents the length in the vertical direction and / or horizontal direction of the opening 103. As shown in FIG. 4, in the area of the flange 104 near the opening 103, the dielectric substrate 102 overlaps, thereby forming an overlapping portion 40 between the flange 104 and the dielectric substrate 102. And inside the overlapping portion 40, from the peripheral edge of the opening 103 (that is, the peripheral edge 104a of the flange 104) towards the inside (the center of the opening), up to a position at a certain distance (length L2) away, a rectangular peripheral area 105 (hatched portion) is formed. The peripheral area 105 is an area near the peripheral edge 104a of the flange 104 within the entire area of the dielectric substrate 102. Specifically, the peripheral area 105 includes an area 105a near the upper side portion 103a, an area 105b near the lower side portion 103b, an area 105c near the right side portion 103c, and an area 105d near the left side portion 103d.

[0029] By providing an antenna in at least any one of the portions of the regions 105a to 105d of the peripheral region 105 in the aforementioned non-heating region 1, compared with the case where the antenna is provided near the center of the opening 103 (i.e., near the center of the dielectric substrate 102), the obstruction of the driver's field of view by the antenna pattern can be suppressed.

[0030] In particular, when the length L1 is set to "1", the ratio of the length L2 to the length L1 is preferably "0.3" (30%) or less, and more preferably "0.2" (20%) or less. Note that the ratio of the length L2 to the length L1 depends on the vehicle type, but in order to arrange a predetermined antenna pattern, it may be "0.03" (3%) or more, and preferably "0.05" (5%) or more. Thereby, while suppressing the obstruction of the driver's field of view by the antenna pattern, when the antenna is arranged in each of the region 105a near the upper side portion 103a and the region 105b near the lower side portion 103b, and / or when the antenna is arranged in each of the region 105c near the right side portion 103c and the region 105d near the left side portion 103d, the distance between the antennas becomes long, and it becomes difficult for the mutual antenna patterns to be capacitively coupled. Therefore, a decrease in antenna gain can be suppressed. Capacitive coupling means that two conductors having a capacitance therebetween function as a capacitor to couple two circuits (antenna patterns).

[0031] In addition, when the region 105a near the upper side portion 103a and the region 105b near the lower side portion 103b are each formed such that the ratio of the length L2 to the length L1 is "0.3" or less, the antenna may be arranged in either one of these regions 105a and 105b. Thereby, in the horizontally long rectangular rear glass, the obstruction of the driver's field of view by the antenna pattern in the vertical direction can be suppressed, and the safety during driving is improved.

[0032] Incidentally, the antenna provided in the peripheral region 105 is preferably arranged at a position as far as possible from the peripheral edge 104a of the flange 104 (metal body). For example, the upper side portion 103a and the antenna pattern provided in the region 105a are less likely to be capacitively coupled to the flange 104 as the shortest distance connecting the closest portions to each other by a virtual straight line becomes larger. The same applies to the antenna patterns provided in each of the regions 105a, 105c, and 105d. The shortest distance is preferably more than 30 mm, and more preferably 75 mm or more. As a result, leakage (attenuation) of the received signal of the antenna to the vehicle 100 is reduced, and noise from the vehicle 100 mixing into the received signal of the antenna is reduced, so that a decrease in antenna gain can be suppressed. Incidentally, when the opening 103 of the vehicle is the above-described back door, if it is sufficiently separated from the metal body, capacitive coupling as described above is less likely to occur, so the antenna may be provided at the outermost end of the peripheral region 105.

[0033] Incidentally, the above antenna may be configured as a diversity antenna that receives at least one type of frequency band among AM broadcast waves, FM broadcast waves, DAB broadcast waves, and DTV broadcast waves on a plurality of channels. For example, if two or more antennas for receiving DTV broadcast waves are provided in the peripheral region 105, these become a diversity antenna. When configuring a diversity antenna, for example, antennas may be provided in each of a portion near the left side portion 103d and a portion near the right side portion 103c within the region 105a near the upper side portion 103a, or antennas may be provided in each of the region 105d near the left side portion 103d and the region 105c near the right side portion 103c. By providing such a diversity antenna, while suppressing interference with the driver's field of view, the degree of freedom in tuning the antenna pattern increases, and the antenna gain can be further increased.

[0034] The configuration shown in the above embodiments is an example of the content of the present invention, and it is possible to combine it with another known technique, and it is also possible to omit or change a part of the configuration without departing from the gist of the present invention.

[0035] This international application claims priority based on Japanese Patent Application No. 2019-237043 filed on December 26, 2019, and incorporates the entire contents of Japanese Patent Application No. 2019-237043 into this international application.

Explanation of Reference Numerals

[0036] 1a, 1b, 1c, 1d: Non-heating region 10, 11, 30: Electronic mirror 20: Display device 100: Vehicle 101: Rear part 102: Dielectric substrate 103: Opening 103a: Upper side part 103b: Lower side part 104: Flange 104a: Peripheral part 105: Peripheral region 105a, 105b, 105c, 105d: Region

Claims

1. An imaging device that images the rear of a vehicle, A display device that displays an image from the imaging device in front of the rear part of the vehicle, A dielectric substrate attached to the rear part of the vehicle, and having, A conductor on the dielectric substrate, The conductor is an antenna that receives radio waves in a predetermined frequency band, The main surface of the dielectric substrate is a non-heating region, When the vertical length of the opening of the vehicle where the dielectric substrate is provided is set to 1, The non-heating region includes a peripheral region that is 0.3 or less from the peripheral edge of the opening toward the inside, The antenna includes a first antenna disposed in a region closer to the upper side of the opening in the peripheral region and a second antenna disposed in a region closer to the lower side of the opening in the peripheral region, The first antenna includes a first antenna pattern, The second antenna includes a second antenna pattern, The first shortest distance between the upper side and the first antenna pattern is more than 30 mm, The second shortest distance between the lower side and the second antenna pattern is more than 30 mm, A vehicle rear monitoring device with an antenna.

2. The first antenna pattern and the second antenna pattern are antenna patterns in which the coupling between each other is lower than when the first antenna and the second antenna are disposed inside the peripheral region, The vehicle rear monitoring device with an antenna according to Claim 1.

3. The first antenna pattern is an antenna pattern in which the coupling with the metal outside the upper side is lower than when the first shortest distance is 30 mm or less and the first antenna is disposed, The second antenna pattern is an antenna pattern in which the coupling with the metal outside the lower side is lower than when the second shortest distance is 30 mm or less and the second antenna is disposed, The vehicle rear monitoring device with an antenna according to Claim 2.

4. An imaging device that images the rear of a vehicle, A display device that displays an image from the imaging device in front of the rear part of the vehicle, A dielectric substrate attached to the rear part of the vehicle, and having, A conductor on the dielectric substrate, The conductor is an antenna that receives radio waves in a predetermined frequency band, The main surface of the dielectric substrate is a non-heating region, When the horizontal length of the opening of the vehicle where the dielectric substrate is provided is set to 1, The non-heating region includes a peripheral region that is 0.3 or less from the peripheral edge of the opening toward the inside, The antenna includes a third antenna disposed in a region closer to the right side of the opening in the peripheral region, and a fourth antenna disposed in a region closer to the left side of the opening in the peripheral region. The third antenna includes a third antenna pattern. The fourth antenna includes a fourth antenna pattern. The third shortest distance between the right side and the third antenna pattern is more than 30 mm. The fourth shortest distance between the left side and the fourth antenna pattern is more than 30 mm. Vehicle rear monitoring device with antenna.

5. The third antenna pattern and the fourth antenna pattern are antenna patterns with lower mutual coupling compared to the case where the third antenna and the fourth antenna are disposed inside the peripheral region. The vehicle rear monitoring device with antenna according to claim 4.

6. The third antenna pattern is an antenna pattern with lower coupling with the metal outside the right side compared to the case where the third antenna is disposed with the third shortest distance being 30 mm or less. The fourth antenna pattern is an antenna pattern with lower coupling with the metal outside the left side compared to the case where the fourth antenna is disposed with the fourth shortest distance being 30 mm or less. The vehicle rear monitoring device with antenna according to claim 5.

7. The dielectric substrate is glass. The vehicle rear monitoring device with antenna according to any one of claims 1 to 6.

8. The antenna receives at least one frequency band of AM broadcast wave, FM broadcast wave, DAB broadcast wave, and DTV broadcast wave. The vehicle rear monitoring device with antenna according to any one of claims 1 to 7.

9. The antenna includes a diversity antenna that receives at least one type of frequency band of AM broadcast wave, FM broadcast wave, DAB broadcast wave, and DTV broadcast wave on a plurality of channels. The vehicle rear monitoring device with antenna according to any one of claims 1 to 8.

10. The imaging device is attached above the dielectric substrate. The vehicle rear monitoring device with antenna according to any one of claims 1 to 9.

11. The imaging device is attached below the dielectric substrate. The vehicle rear monitoring device with antenna according to any one of claims 1 to 9.

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