JP2018117236A - vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology capable of achieving both heat insulation properties and antenna performance, in a vehicle where a roof panel transmitting light and an antenna device provided to a rear window are provided.SOLUTION: In a vehicle 1, a roof panel 10 transmits light. A heat insulating sheet 12 is provided to the roof panel 10 and has conductivity. An antenna device is provided to a rear window 14. The length of the heat insulating sheet 12 in a vehicle width direction is longer than the length of the antenna device in the vehicle width direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle provided with a roof panel that transmits light and an antenna device for a rear window.

  A technology is known in which a roof panel of a vehicle is configured to allow light to pass through and a heat shield sheet is provided on the roof panel in order to suppress heat transfer from the outside of the vehicle to the vehicle interior (see, for example, Patent Document 1). .

JP 2009-090832 A

  In the said technique, in order to improve heat-shielding property, providing a conductive layer in a heat-shielding sheet | seat is considered. However, when the rear window is provided with an antenna, the heat-shielding sheet having conductivity may adversely affect the antenna and reduce the antenna performance.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique capable of achieving both heat shielding and antenna performance in a vehicle provided with a roof panel that transmits light and an antenna device for a rear window. There is to do.

  In order to solve the above-described problems, a vehicle according to an aspect of the present invention includes a roof panel that transmits light, a heat-shielding sheet having conductivity provided in the roof panel, and an antenna device provided in a rear window. . The length of the heat shield sheet in the vehicle width direction is longer than the length of the antenna device in the vehicle width direction.

  According to this aspect, since the length of the heat shield sheet in the vehicle width direction is longer than the length of the antenna device in the vehicle width direction, the resonance frequency of the heat shield sheet can be removed from the frequency band of the radio wave received by the antenna device. Thereby, the bad influence to the antenna apparatus by the heat shield sheet which has electroconductivity can be suppressed. Therefore, in a vehicle provided with a roof panel that transmits light and an antenna device for a rear window, both heat shielding properties and antenna performance can be achieved.

  The antenna device may include a plurality of linear antenna elements extending in the vehicle width direction and receive radio waves in the frequency band of FM radio.

  ADVANTAGE OF THE INVENTION According to this invention, in the vehicle provided with the roof panel which permeate | transmits light, and the antenna apparatus of a rear window, heat insulation and antenna performance can be made compatible.

1 is a side view of a vehicle according to an embodiment. It is a top view which shows the roof panel of FIG. It is a top view which shows the rear window of FIG. It is a figure which shows the relationship between the length W1 of the vehicle width direction of a heat shield sheet, and the resonance frequency of a heat shield sheet. It is a figure which shows the relationship between the length L1 of the heat shield sheet in the vehicle front-back direction and the resonance frequency of the heat shield sheet.

  FIG. 1 is a side view of a vehicle 1 according to an embodiment. FIG. 2 is a plan view showing the roof panel 10 of FIG. FIG. 3 is a plan view showing the rear window 14 of FIG. 2 and 3 are views from the outside of the vehicle. As shown in FIGS. 1 to 3, the vehicle 1 includes a roof panel 10, a heat shield sheet 12, a rear window 14, and an antenna device 20.

  The roof panel 10 is made of glass and transmits light. The roof panel 10 is also referred to as a glass roof. The heat shield sheet 12 is a sheet that suppresses the transfer of heat from the outside of the vehicle to the vehicle interior, and includes a conductive layer made of a conductive material such as a metal for enhancing the heat shield property, and has conductivity. The heat shield sheet 12 has a substantially rectangular shape having two sides substantially parallel to the vehicle front-rear direction d1 and two sides substantially parallel to the vehicle width direction d2, and is provided on the roof panel 10. Specifically, the heat shield sheet 12 is affixed to the surface of the roof panel 10 on the vehicle interior side or the vehicle exterior surface. The roof panel 10 may be made of laminated glass. In this case, the heat shield sheet 12 may be provided in the laminated glass.

  The rear window 14 is made of glass. The antenna device 20 is a glass antenna and is provided in the rear window 14. The antenna device 20 receives radio waves in the frequency band of FM radio and radio waves in the frequency band of AM radio.

  The length W1 of the heat shield sheet 12 in the vehicle width direction d2 is longer than the length W2 of the antenna device 20 in the vehicle width direction d2. The length W2 of the antenna device 20 represents the length of the longest portion of the antenna device 20 in the vehicle width direction d2. The length W2 is determined based on the lowest frequency of the frequency band of the FM radio to be received, and is set to be slightly longer than ¼ of the wavelength of the radio wave having the lowest frequency.

  As shown in FIG. 3, the antenna device 20 includes a first feeding unit 21, a second feeding unit 22, a third feeding unit 23, an AM antenna 30, an FM main antenna 50, an FM sub antenna 60, Have The AM antenna 30 and the FM main antenna 50 are provided in an elongated area in the vehicle width direction d2 above the rear window 14. The FM sub-antenna 60 is provided in a region other than the region where the AM antenna 30 and the FM main antenna 50 are provided in the rear window 14. The FM main antenna 50 and the FM sub-antenna 60 constitute a diversity antenna.

  The AM antenna 30 has a plurality of linear antenna elements 31 to 43. The FM main antenna 50 includes a plurality of linear antenna elements 51 to 53. The FM sub-antenna 60 has a plurality of linear antenna elements 61 to 71. The plurality of antenna elements 31 to 43, 51 to 53, and 61 to 71 are made of a conductive material such as metal and are attached to the vehicle interior side of the rear window 14.

  In the following, the right is the direction R in FIG. 3, the left is the direction L, the upper is the direction U, and the lower is the direction D. The direction R and the direction L are the same direction as the vehicle width direction d2.

  The first power feeding unit 21 is a feeding point for AM radio for connecting the AM antenna 30 to a signal processing circuit (not shown). The first power feeding unit 21 is attached above the right end of the rear window 14.

  The right end of the antenna element 31 is connected to the first power feeding unit 21. The antenna element 31 extends substantially parallel to the upper end of the rear window 14 from the vicinity of the right end of the rear window 14 to the vicinity of the left end. That is, the antenna element 31 extends substantially in the vehicle width direction d2.

  The antenna element 32 crosses the antenna element 31 and extends vertically on the left side of the center of the rear window 14 in the vehicle width direction d2. The antenna element 32 extends from the upper end of the rear window 14 to the vicinity of a position that is approximately 1/4 of the vertical length of the rear window 14.

  The antenna element 33 extends substantially parallel to the upper end of the rear window 14 from the upper end of the antenna element 32 to the left and right sides. The antenna element 33 is shorter than the antenna element 31. The antenna element 34 intersects the antenna element 32 and extends to the left and right sides of the antenna element 32 below the antenna element 33 and substantially parallel to the antenna element 33. The antenna element 34 is longer than the antenna element 33.

  The antenna element 35 crosses the antenna element 32 and extends to the left and right sides of the antenna element 32 below the antenna element 34 and substantially parallel to the antenna element 34. The antenna element 36 intersects the antenna element 32 and extends to the left and right sides of the antenna element 32 below the antenna element 35 and substantially parallel to the antenna element 35.

  The lengths of the antenna elements 34 to 36 are substantially equal, and the right ends of the antenna elements 34 to 36 are connected by an antenna element 37, respectively. The left ends of the antenna elements 34 to 36 are connected to each other by an antenna element 38. The antenna element 38 extends downward until it exceeds the antenna element 31, bends to the right, and extends in front of the antenna element 32 substantially parallel to the antenna element 31.

  The antenna element 39 intersects the antenna element 32 and extends to the left and right sides of the antenna element 32 between the antenna element 31 and the antenna element 36 so as to be substantially parallel to the antenna element 31. The antenna element 39 is longer than the antenna element 33 and shorter than the antenna element 34.

  The antenna element 40 extends to the left from the antenna element 32 below the antenna element 38 and substantially parallel to the antenna element 38. The antenna element 41 intersects the antenna element 32 and extends to the left and right sides of the antenna element 32 below the antenna element 40 and substantially parallel to the antenna element 40. The antenna element 42 extends substantially parallel to the antenna element 41 from the lower end of the antenna element 32 to the left and right sides.

  In the upper right region of the rear window 14, the antenna element 43 extends upward from the first power feeding portion 21, then extends to the left, then extends downward, and then extends to the right.

  The second feeding unit 22 is a feeding point for FM radio for connecting the FM main antenna 50 to a signal processing circuit (not shown). The second power feeding unit 22 is attached below the first power feeding unit 21 in the vicinity of the right end of the rear window 14.

  The antenna element 51 extends upward from the second power feeding part 22 to the front of the first power feeding part 21, and then bends to the left, between the antenna element 31 and the antenna element 41, to the front of the center of the rear window 14, The antenna element 31 extends substantially in parallel. The antenna element 51 extends on a virtual extension line of the antenna element 38.

  The right end of the antenna element 52 is connected to the second power feeding unit 22. The antenna element 52 extends substantially parallel to the antenna element 51 between the antenna element 51 and the antenna element 41 from the vicinity of the right end of the rear window 14 to the front of the antenna element 32. The antenna element 52 extends on a virtual extension line of the antenna element 40.

  The antenna element 53 extends in the vertical direction from the antenna element 51 toward the antenna element 52 near the center of the antenna element 51 in the vehicle width direction d2, and connects the antenna elements 51 and 52.

  Although the AM antenna 30 and the FM main antenna 50 are not connected to each other, the AM antenna 30 functions to widen the frequency band of the FM main antenna 50. That is, the frequency band of the FM main antenna 50 is determined by the AM antenna 30 and the FM main antenna 50 as a whole.

  The 3rd electric power feeding part 23 is an electric power feeding point for FM radio for connecting FM subantenna 60 to the signal processing circuit which is not illustrated. The third power feeding unit 23 is attached under the second power feeding unit 22 in the vicinity of the right end of the rear window 14.

  The antenna element 61 extends from between the second power feeding part 22 and the third power feeding part 23 along the right end of the rear window 14 to the front of the lower end of the rear window 14 and is connected to the third power feeding part 23. The antenna element 62 extends substantially parallel to the antenna element 42 from the upper end of the antenna element 61 to the vicinity of the left end of the rear window 14 below the antenna element 42.

  The antenna element 63 extends along the left end of the rear window 14 from the left end of the antenna element 62 to the front of the lower end of the rear window 14. The antenna element 64 extends substantially parallel to the lower end of the rear window 14 from the lower end of the antenna element 63 to the lower end of the antenna element 61 near the right end of the rear window 14. The antenna elements 61 to 64 form a slender loop in the vehicle width direction d2, and the length of the loop in the vehicle width direction d2 is the length W2.

  The antenna element 65 extends upward from the vicinity of the right end of the antenna element 62, then bends to the left, and extends below the antenna element 42 to the vicinity of a virtual extension line of the antenna element 53 substantially parallel to the antenna element 42.

  The antenna elements 66 and 67 extend from the antenna element 62 to the front of the antenna element 64 substantially symmetrically with respect to the virtual center line of the rear window 14 in the vehicle width direction d2. The antenna element 67 is located on a virtual extension line of the antenna element 32.

  The antenna element 68 extends from the vicinity of the left end of the antenna element 62 upward to the left side of the antenna element 38, and then bends to the right in a curved shape.

  The antenna element 69 extends downward from the vicinity of the left end of the antenna element 64, and then bends to the right and extends to the right along the lower end of the rear window 14 to the center of the rear window 14 in the vehicle width direction d2. The antenna element 70 extends to the right from the antenna element 64 side of the portion extending below the antenna element 69 to the center of the rear window 14 in the vehicle width direction d2 substantially parallel to the antenna element 64. The antenna element 71 extends downward from the antenna element 64 at the center of the rear window 14 in the vehicle width direction d2, and then bends to the left and extends to the left between the antenna elements 69 and 70, close to the antenna element 70.

  Next, operations and effects of the vehicle 1 will be described with reference to FIGS. Here, it is assumed that the frequency band FB of FM radio is 76 to 108 [MHz] as an example. As an example, the length W2 of the antenna device 20 in the vehicle width direction d2 is about 1100 [mm] so that radio waves in the frequency band FB can be received.

  FIG. 4 is a diagram showing the relationship between the length W1 of the heat shield sheet 12 in the vehicle width direction d2 and the resonance frequency of the heat shield sheet 12. As shown in FIG. In FIG. 4, the length L1 of the heat shield sheet 12 in the vehicle front-rear direction d1 is a constant 415 [mm].

  The theoretical value 100 of the resonance frequency in FIG. 4 is calculated using W1 = λ / 4. The measured value 102 of the resonance frequency is measured as follows. First, in the vehicle 1 shown in FIGS. 1 to 3, the heat shield sheet 12 and the network analyzer are connected by a coaxial cable. The ground of the coaxial cable is connected to the body of the vehicle 1. In this state, at each length W1, the S parameter (S11) is measured by the network analyzer, and the resonance frequency is obtained from the measurement result.

  As shown in FIG. 4, the theoretical value 100 and the actual measurement value 102 of the resonance frequency of the heat shield sheet 12 become smaller as the length W1 becomes longer. Therefore, the resonance frequency has a correlation with the length W1. Further, the theoretical value 100 and the actual measurement value 102 of the resonance frequency are relatively coincident. Since the measured value 102 of the resonance frequency is within the frequency band FB of the FM radio when the length W1 is around 900 [mm], the resonance of the heat shield sheet 12 affects the radio waves in the frequency band FB of the FM radio. Therefore, under this condition, antenna performance such as directivity in the antenna device 20 is lowered, and FM radio reception performance is lowered.

  On the other hand, when the length W1 of the heat shield sheet 12 in the vehicle width direction d2 is longer than 1100 [mm], which is the length W2 of the antenna device 20 in the vehicle width direction d2, the resonance frequency is 76 [MHz]. ] Is lower. Therefore, the resonance of the heat shield sheet 12 does not affect the radio waves in the frequency band FB of the FM radio. Therefore, under this condition, a decrease in antenna performance of the antenna device 20 can be suppressed, and a decrease in reception performance of FM radio can be suppressed.

  In addition, when the length W1 of the heat shield sheet 12 in the vehicle width direction d2 is shorter than about 700 [mm], the resonance frequency is higher than 108 [MHz]. In this case as well, a decrease in antenna performance can be suppressed, but since the area of the heat shield sheet 12 is limited, the heat shield performance is lowered.

  FIG. 5 is a diagram illustrating a relationship between the length L1 of the heat shield sheet 12 in the vehicle front-rear direction d1 and the resonance frequency of the heat shield sheet 12. In FIG. 5, the length W1 of the heat shield sheet 12 in the vehicle width direction d2 is a constant 792 [mm]. The theoretical value 104 of the resonance frequency is calculated using L1 = λ / 4. The measured value 106 of the resonance frequency is measured in the same manner as in FIG.

  As shown in FIG. 5, the theoretical value 104 of the resonance frequency of the heat shield sheet 12 decreases as the length L1 increases. However, the actual measurement value 106 hardly changes regardless of the length L1. Accordingly, the actually measured resonance frequency has no correlation with the length L1. Therefore, even if the length L1 is adjusted, the antenna performance hardly changes. Therefore, the length L1 can be set so as to obtain a desired heat shielding property.

  In the heat shield sheet 12, the alternating current mainly flows in the vicinity of the end faces of the heat shield sheet 12 in the vehicle front-rear direction d1 and the vehicle width direction d2. Therefore, the alternating current flowing in the vehicle width direction d2 (that is, the direction of the length W1) in the vicinity of the end face of the heat shield sheet 12 is parallel to the electric field vector of the antenna device 20 facing the vehicle width direction d2. On the other hand, the alternating current flowing in the vehicle front-rear direction d1 (that is, the length L1 direction) on the end surface of the heat shield sheet 12 is orthogonal to the electric field vector of the antenna device 20. These are considered to be a cause of the fact that the resonance frequency has a correlation with the length W1 and has no correlation with the length L1.

  Thus, according to this embodiment, since the length W1 of the heat shield sheet 12 in the vehicle width direction d2 is longer than the length W2 of the antenna device 20 in the vehicle width direction d2, the resonance frequency of the heat shield sheet 12 is set to the antenna. The frequency band FB of the radio waves of the FM radio received by the device 20 can be removed. Thereby, the bad influence to the antenna apparatus 20 by the heat shield sheet 12 which has electroconductivity can be suppressed. The heat shield sheet 12 having conductivity exhibits a heat shield property superior to that of a heat shield sheet not having conductivity. Therefore, in the vehicle 1 in which the roof panel 10 that transmits light and the antenna device 20 of the rear window 14 are provided, both heat shielding properties and antenna performance can be achieved.

  The present invention has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications can be made to the combination of each component and each processing process, and such modifications are within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 10 ... Roof panel, 12 ... Thermal insulation sheet, 14 ... Rear window, 20 ... Antenna apparatus, 31-43, 51-53, 61-71 ... Antenna element.

Claims (2)

A roof panel that transmits light;
A heat-shielding sheet having conductivity provided on the roof panel;
An antenna device provided in the rear window,
The length of the heat shield sheet in the vehicle width direction is longer than the length of the antenna device in the vehicle width direction.   The vehicle according to claim 1, wherein the antenna device includes a plurality of linear antenna elements extending in a vehicle width direction, and receives radio waves in an FM radio frequency band.

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