JPH08181535A - Radio wave reflecting body and vehicle provided with same - Google Patents

Abstract

PURPOSE: To improve probability of sensing an object by a radar by forming a triangle cone with material reflecting a high frequency, connecting the cones at their open bottom sides to form a sawtooth wave cross section in side view. CONSTITUTION: Triangle cones made of material reflecting a high frequency are connected consecutively to form a radio wave reflecting body 10 of a sawtooth wave in side view. Then the reflecting body 10 is provided inside a mold 14 fitted for decoration, protection against hand and finger, prevention of deformation by collision along the surrounding (door and bumper mold or the like) around a vehicle 13. When a radio wave from a radar at the front part of a succeeding vehicle is sent while scanning horizontally by providing the reflecting body 10 to this position, the radio wave is efficiently reflected by the reflecting body 10 and a front object vehicle with the reflecting body 10 is surely identified from an opposite vehicle or a guard rail or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio wave reflector used in a preceding vehicle identification device and a vehicle equipped with the same.

[0002]

2. Description of the Related Art A radar is provided in the front of a vehicle to emit a radio wave toward a target vehicle ahead, and the distance from the target vehicle can be calculated from the time difference between the time when the radio wave is transmitted and the time when the radio wave reflected by the target vehicle is received. Although a method of calculating is known, it malfunctions by detecting reflected waves from road incidental equipment such as oncoming vehicles and guardrails. Japanese Unexamined Patent Publication (Kokai) No. 61-40579 discloses an identification device which eliminates this drawback and allows a vehicle ahead to be identified as an oncoming vehicle.

In this identification device, a radio wave absorbing paint in which a radio wave absorbing material such as ferrite is mixed with a paint and a radio wave reflecting paint in which the radio wave absorbing material is not mixed are separately applied to the rear portion of a vehicle having a specific pattern, Radio waves from a radar placed in front of the following vehicle are horizontally scanned and transmitted, and a unique reflection pattern such as absorption and reflection is generated by the pattern so that the vehicle in front is distinguished from an oncoming vehicle or a guardrail. ing.

[0004]

However, a high frequency wave, for example, a millimeter wave has an extremely strong straightness similar to that of light, and the incident direction of the radio wave emitted from the radar is perpendicular to the plane portion of the target. If not, the reflected wave has a property of traveling in a direction different from the incident direction. For this reason, in a radar system in which the transmitting and receiving antennas are close to each other, the ability to detect a target object such as a vehicle having many curved portions is deteriorated.

The present application has been made in order to solve the above problems, and its purpose is to dispose a radio wave reflector capable of reflecting a radio wave incident from any direction in a radio wave arrival direction on a target object. , To increase the detection probability of radar.

[0006]

[Means for Solving the Problems] By the way, when a high frequency wave, for example, a millimeter wave, has an opening at the bottom of a triangular pyramid and the opening is oriented in the direction of arrival of radio waves, the incoming radio waves return to the direction of arrival. Is known.

In view of this point, in order to solve the above-mentioned problems, the radio wave reflector according to the present invention is formed by forming a triangular pyramid with a material that reflects high frequency waves, and continuously connecting the triangular pyramids so that the bottom surface of the triangular pyramid has a sawtooth shape in a side view. It was a cross section.

At this time, it is preferable that the length of the base of the triangular pyramid is at least twice the wavelength of the high frequency wave, and a protective member made of a radio wave transmitting material is provided on the opening surface.

Further, a vehicle equipped with the radio wave reflector according to the present invention is arranged inside a mall in which the radio wave reflector is mounted around the vehicle.

[0010]

[Function] A triangular pyramid made of a material that reflects high frequencies is connected to form a sawtooth-shaped radio wave reflector in a side view, and the radio wave transmitted from a following vehicle is attached to the molding part to form a triangle side surface of the triangle pyramid. It is reflected by and returned to the direction of arrival of radio waves.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a development view of a triangular pyramid constituting a radio wave reflector according to the present invention and a perspective view showing an assembled state.

The triangular pyramid 1 is a square plate made of a metal that reflects radio waves (for example, light weight and easy to process aluminum), and four right triangles 2 to 5 are formed by connecting the vertices of the square. One of the two (here, right-angled triangle 5
After cutting (see FIG. 1 (a)), the triangles 2 and 4 are bent in the same direction (for example, inside) through the sides 6 and 7, and the sides 8 and 9 are bonded by welding or the like. It is formed with 1a, 1b, 1c as the base (see FIG. 1B).

The triangular pyramid 1 thus formed has sides 1
The bottom surface composed of a, 1b, and 1c is to be opened, and when the opening 1d is arranged so as to be oriented in the direction of arrival of radio waves, the radio waves coming from the direction of the arrow a have a right triangle 2 to 2.
The light beam is mirror-reflected 3 times on the side surface of 4 and returns in the same direction as the arrow a (radio wave arrival direction) as shown by the arrow b.

Here, when the frequency of the radio wave used is, for example, 60 GHz, the wavelength is 5 mm, so the lengths of the bottom sides 1a, 1b, 1c are twice or more the length of 10 mm or more. Is preferred.

FIG. 2 is a plan view of a radio wave reflector according to the present invention formed by connecting the triangular pyramids in series. The same parts as those in FIG. 1 are designated by the same reference numerals. 2A shows eight triangular pyramids arranged side by side, FIG. 2B shows eight triangular pyramids arranged side by side, and FIG. 2C shows 18 triangular pyramids arranged side by side. The case where they are arranged is shown. Then, it is desirable to form a plurality of triangular pyramids by pressing an aluminum flat plate. This method is easier to manufacture than welding.

FIG. 3 is a sectional view taken along the line AA of FIG. 2B, and the same parts as those in FIG. 2B are designated by the same reference numerals.
The radio wave reflector 10 has a sawtooth shape in a side view, and the triangular pyramid 1 ... Is formed on the upper surface of the opening 1d of the triangular pyramid 1 ...
Member for protecting the side surface of the substrate from damage due to contact, for example, a protective film 11 made of polypropylene (PP) resin
To a thickness of about 3 to 4 mm.

This polypropylene (PP) resin protective film 1
No. 1 has a property of sufficiently transmitting radio waves and having a level of about -3 to 4 dB as compared with the case without the protective film 11. At this time, the intermediate layer 1 formed between the side surfaces of the triangular pyramids 1 ... And the protective film 11.
2 is filled with air or a dielectric.

Since the radio wave reflector 10 has such a structure, in any of the triangular pyramids 1, ..., Radio waves coming from the direction of the arrow a and transmitted through the protective film 11 form the triangular pyramids 1. The side surface composed of 2 to 4 is specularly reflected three times, and the desired radio wave reversely passes through the protective film 11 and returns in the direction indicated by the arrow b (radio wave arrival direction).

FIG. 4 is a side view of a vehicle equipped with a molding provided with the radio wave reflector according to the present invention. The same parts as those in FIG. 3 are designated by the same reference numerals. In this embodiment, the radio wave reflector 10 is provided along the periphery of the vehicle 13 (door, bumper molding, etc.) inside the molding 14 which is attached in a belt shape for decoration, protection of hands and fingers, and deformation prevention by collision. I am trying to provide it.

By providing the radio wave reflector 10 at this position, when the radio wave from the radar arranged in the front part of the following vehicle (not shown) is horizontally scanned and transmitted, the radio wave reflector 10 can efficiently transmit the radio wave. This radio wave reflector 1
The target vehicle in front of which 0 is attached can be reliably identified as an oncoming vehicle or a guardrail.

FIG. 5 is a sectional view taken along the line BB in FIG. 4, and the same parts as those in FIG. 4 are designated by the same reference numerals. Radio wave reflector 1
The bottom surface 10a of 0 is a groove 15 formed around the vehicle 13.
It is affixed using an adhesive such as glue 16 and the protective film 1
1 (protective member) is provided with a plurality of hooks 18 corresponding to holes 17 provided at predetermined intervals along the concave groove 15, as in the case of attaching a molding 14 made of, for example, conventional resin. By engaging the hook 18 with the hole 17, the molding 14 having the radio wave reflector 10 therein is attached around the vehicle 13.

Next, another embodiment of the mall will be described.
FIG. 6 is a plan view of a main part of a molding provided with a radio wave reflector according to the present invention. As shown in this figure, by mounting a sensor unit 19 on a discontinuous portion of the radio wave reflector 10,
It is possible to build a sensor system that is completely unaware of its appearance.

In each of the above-mentioned embodiments, an example in which the radio wave reflector is attached to the vehicle is shown.
It may be attached to a structure on the road such as a wall or a fence, or a roadside tree.

[0024]

EFFECTS OF THE INVENTION The present invention having the above-mentioned structure exhibits the following effects. According to the first aspect, since the triangular pyramid is formed of a material that reflects high frequencies and the bottom surface of the triangular pyramid is continuously formed to have a sawtooth-shaped cross section in a side view, the radio wave is transmitted in a triangular shape even when it is not perpendicular to the plane portion. It can be reflected by the side surface of the eggplant and returned to the direction of arrival of the radio wave, which increases the probability of detection of the target object by the radar.

Since the length of the base of the triangular pyramid is not less than twice the wavelength of the high frequency wave, the incoming radio wave is efficiently reflected in the incoming direction.

According to the third aspect, since the protective member made of the radio wave transmitting material is provided at the bottom opening of the triangular pyramid, the side surface of the triangular pyramid can be surely protected from the influence of disturbance such as collision.

According to the present invention, since the radio wave reflector is arranged inside the mall mounted around the vehicle, it is possible to reliably detect the target vehicle, which is conventionally reflected on the surface of the vehicle body and difficult to detect, by the radar provided on the following vehicle. As a result, the target vehicle can be reliably identified as the oncoming vehicle or the guardrail.

[Brief description of drawings]

FIG. 1 is a development view of a triangular pyramid forming a radio wave reflector according to the present invention and a perspective view showing an assembled state thereof.

FIG. 2 is a plan view of a radio wave reflector according to the present invention.

FIG. 3 is a sectional view taken along the line AA of FIG. 2;

FIG. 4 is a side view of a vehicle equipped with a molding provided with a radio wave reflector according to the present invention.

FIG. 5 is a sectional view taken along line BB of FIG. 4;

FIG. 6 is a plan view of a main part of a molding provided with a radio wave reflector according to the present invention.

[Explanation of symbols]

1 ... Triangular pyramid, 2-5 ... Right triangle, 10 ... Radio wave reflector,
11 ... Protective film, 12 ... Intermediate layer, 13 ... Vehicle, 14 ... Mole, 15 ... Concave groove, 16 ... Glue, 17 ... Hole, 18 ... Hook, 19 ... Sensor unit.

Claims (4)

[Claims] 1. A radio wave reflector characterized in that a triangular pyramid is formed of a material that reflects high frequencies, and the bottom surface of the triangular pyramid is opened so that the triangular pyramid has a sawtooth cross section in a side view. 2. The radio wave reflector according to claim 1, wherein the base length of the triangular pyramid is at least twice the wavelength of the high frequency wave. 3. The radio wave reflector according to claim 1, wherein a protective member made of a radio wave transmitting material is provided on the bottom opening of the triangular pyramid. 4. A vehicle provided with a radio wave reflector, wherein the radio wave reflector is arranged inside a mall mounted around the vehicle.