JP2006287500A - Radio wave transmissive cover member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further increase a stereoscopic effect on a surface by enabling to make the surface of a front side transparent layer be a convex surface having a larger curvature while avoiding a problem that a parting line of a decorating layer becomes unclear. <P>SOLUTION: A front grill garnish 1 is arranged on an opening 2a formed on a front grill 2 as an exterior part having a back facing a radar apparatus 3, and is used as a radio wave transmissive cover member capable of transmitting a radio wave transmitted/received by the radar apparatus 3. The garnish 1 is provided with a front side transparent layer 4, a rear side base material layer 5, and a decorating layer, and the layer 4 is formed into a flat convex lens shape protruding on the front side. The convex lens surface of the front side of the layer 4 is made to be largely bent while maintaining the flatness of the front side surface of the layer 4, so that the convex surface has a larger curvature. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radio wave transmitting cover member, and more particularly, a millimeter that is disposed in the opening so as to close an opening formed in an exterior part on which a radar device is disposed behind, and the radar device transmits and receives. The present invention relates to a radio wave permeable cover member capable of transmitting radio waves such as waves and microwaves. The radio wave transmitting cover member of the present invention is suitable for, for example, a front grill garnish disposed in an opening formed in a front grill as an exterior part for a vehicle in which an in-vehicle radar device using millimeter waves is disposed behind. Can be used.

  There are, for example, a laser type using a laser beam and a radio type using a radio wave such as a millimeter wave or a microwave. Among these, the radio wave type radar device is less susceptible to rain, snow, fog, etc. compared to the laser type, and if the radio wave has a short wavelength such as millimeter wave, it is excellent in straightness and directivity. In recent years, it has attracted attention because it can contribute to downsizing.

  Such an on-vehicle radar device transmits a millimeter wave or the like and receives a millimeter wave or the like reflected by an object to detect an obstacle ahead of the vehicle or measure an inter-vehicle distance. used. For this reason, the on-vehicle radar device is disposed, for example, behind the front grille, which is an exterior part on the front surface of the vehicle. However, the front grill itself has many vents for taking air into the engine room and the surface is often metal-plated. It has a structure that makes it difficult to permeate well. If an opening for transmitting radio waves is formed at the front position of the laser device of the front grille, radio waves can be transmitted through the opening, but in this state, an engine such as a radar device can be passed through the opening from the front of the vehicle. Since the inside of the room is visible, the design is impaired. Therefore, by providing a front grill garnish as a radio wave permeable cover member that can transmit radio waves in the radio wave transmission opening formed in the front grill, design and radio wave transmission can be improved. ing.

  As such a radio wave transmissive cover member, a front side transparent layer made of a radio wave transmissive and transparent material disposed on the front side of the exterior part, and a back side base material layer made of a radio wave transmissive material arranged on the back side of the exterior part, What is provided with the decoration layer arrange | positioned between these front side transparent layers and back side base material layers is conventionally known (for example, refer patent document 1).

  This radio wave permeable cover member forms a metal thin film by indium vapor deposition or the like on the inner surface (surface on the back side base material layer side) of the front side transparent layer made of polycarbonate (PC), polymethyl methacrylate (PMMA) or the like, A masking paint is applied to the portion where the metal thin film remains to form a masking coating, and then the metal thin film other than the masking coating is removed by etching, and then the acrylic coating is applied to the entire inner surface of the front transparent layer. To form a black paint film, and finally a back side base material layer made of polyphenylene ether (PPE), acrylonitrile / butadiene / styrene copolymer (ABS), etc. is applied to the inner surface of the front side transparent layer with an adhesive or the like. It is manufactured by pasting. In this radio wave transmitting cover member, in a portion having a metallic luster, a concave portion is provided in advance on the inner surface of the front transparent layer and a convex portion is provided in the back side base material layer. Thus, a decorative layer is constituted by the metal thin film and the masking coating film (the masking coating film itself cannot be seen from the front side of the cover member) remaining in the recess without being etched and the black coating film. For this reason, when the radio wave transmissive cover member is viewed from the front side, the metallic thin film having a metallic luster formed on the convex portion of the back side base material layer is in the front side transparent layer with the dark black coating film as the background. It appears to be three-dimensional.

  Here, in such a radio wave transmitting cover member, the thickness of the radio wave transmitting material affects the radio wave transmission. That is, the radio wave transmission property differs between the thick and thin portions of the radio wave transmitting material. Since the radio wave transmitting cover member has a significantly reduced permeability due to an extreme change in wall thickness, the surface on the front side is preferably a smooth surface or a gently curved surface.

In addition, as another radio wave permeable cover member, instead of leaving the metal thin film as the decoration layer by masking and etching, printing other than the portion that becomes the decoration layer of the metal thin film was subjected to printing called screen printing. Things are also known. If a decorative layer of a predetermined shape is formed by printing in this way, the parting line of the decorative layer having a metallic luster (the boundary line between the decorative layer and the surrounding printed layer) is compared with the case of masking and etching. ) Can be made clearer and the design can be further improved.
JP 2002-135030 A

  By the way, the radio wave transmitting cover member as described above generally has a flat plate-like overall shape and the surface of the front transparent layer is a flat surface, or has a very gently curved whole shape and a front side. In many cases, the surface of the transparent layer is a gentle convex curved surface with a slight convex on the front side. Thus, for the purpose of design to increase the stereoscopic effect on the surface of the front side transparent layer, the surface of the front side transparent layer is made a convex curved surface that is convex on the front side, and the curved surface constituting the convex curved surface is There is a case where it is required to be curved to a curved surface having a large curvature.

  However, in order to meet such a design requirement, when the entire cover member is greatly curved to have a curved shape with a large curvature, the masking coating film is accurately applied as the curvature of the decorative layer portion also increases. It becomes difficult to perform printing for making the parting line of the decorative layer clearer. For this reason, formation and printing of a masking coating film cannot be performed correctly, and there exists a problem that the parting line of a decoration layer becomes unclear.

  The present invention has been made in view of the above circumstances, and in a radio wave transmitting cover member provided with a front side transparent layer, a back side base material layer, and a decorative layer disposed therebetween, a parting line of the decorative layer It is possible to make the surface of the front side transparent layer a convex curved surface with a larger curvature while avoiding the problem of blurring the image, and to solve the design request to enhance the stereoscopic effect on the surface. It is a technical issue.

  The radio wave transmitting cover member of the present invention that solves the above problems is disposed in the opening so as to close the opening formed in the exterior part on which the radar apparatus is disposed behind, and the radar apparatus A radio wave transmissive cover member capable of transmitting received radio waves, a front side transparent layer disposed on the front side of the exterior part, a back side base material layer disposed on the back side of the exterior part, the front side transparent layer, And a decorative layer disposed between the back-side base material layers, and at least a part of the front-side transparent layer has a plano-convex lens shape that is convex on the front side.

  Here, “front side” and “back side” in the specification of the present application mean the front side and the back side in a state where the radio wave transmitting cover member of the present invention is disposed in the opening of the exterior part. That is, the radar device side disposed behind the radio wave transmissive cover member is the back side, and the external side from which radio waves from the radar device are transmitted through the radio wave permeable cover member is the front side.

  Further, the “plano-convex lens shape” in the present specification has a convex lens surface (convex curved surface) on one surface side and a substantially flat surface that is not curved on the other surface side (not necessarily a completely flat surface). This means, for example, that the step includes a stepped surface (uneven surface) for giving a decorative layer a three-dimensional effect on a substantially flat surface on the other surface side.

  In this radio wave transmitting cover member, since at least a part of the front transparent layer has a plano-convex lens shape convex to the front side, the surface on the back side (decorative layer side) of the front transparent layer maintains flatness. The surface is almost flat. That is, if the plano-convex lens shape is used, the convex lens surface on the front side of the front transparent layer can be largely curved to obtain a convex curved surface with a larger curvature while maintaining the flatness of the back surface of the front transparent layer. And if the surface on the back side of the front side transparent layer maintains flatness and is a substantially flat surface, the decorative layer itself can be maintained flat without being curved, and the printing technique and the like can be performed satisfactorily. It becomes possible. Therefore, while avoiding the problem that the parting line of the decorative layer becomes unclear, it is possible to make the surface of the front transparent layer a convex curved surface with a larger curvature, and to enhance the stereoscopic effect on the surface, on the design Can respond to requests.

  In this radio wave transmitting cover member, since at least a part of the front transparent layer has a plano-convex lens shape, the radio wave transmitted through the plano-convex lens portion can be focused by refraction. For this reason, since the radio wave transmitted from the radar device can be focused by the radio wave permeable cover member, the directivity of the radio wave is improved, and an object located in the vicinity of the radio wave permeable cover member is reliably detected. Is possible.

  In a preferred aspect of the radio wave transmitting cover member of the present invention, at least a part of the back side base material layer has a plano-convex lens shape that is convex on the back side.

  In this radio wave transmitting cover member, both the front side transparent layer and the back side base material layer have a plano-convex lens shape, so that the cover member as a whole has a biconvex lens shape, compared with the case of a plano-convex lens shape. This shortens the focal length. For this reason, the directivity of the radio wave transmitted through the radio wave permeable cover member can be further increased, and an object located closer to the radio wave permeable cover member can be reliably detected.

  In a preferred aspect of the radio wave transmitting cover member of the present invention, the back side base material layer is formed of a Fresnel lens surface having a focusing lens function in which at least a part of the back side has a focusing lens function to focus the transmitted radio wave by refraction.

  In this radio wave transmitting cover member, the front side transparent layer has a plano-convex lens shape and the back side base material layer has a Fresnel lens shape having a focusing lens function, so that the cover member as a whole has a biconvex lens shape. Similarly, the focal length is shortened, and it is possible to reliably detect an object located closer to the radio wave transmitting cover member. In addition, since the thickness is not increased in the case of the Fresnel lens shape as in the case of the convex lens shape, it is possible to reduce the thickness of the entire cover member as compared with the case where the back side base material layer is formed into a plano-convex lens shape. .

  Preferably, the exterior component is a front grill as a vehicle exterior component, and the radio wave transmitting cover member of the present invention is a front grill garnish disposed in the opening of the front grill.

  According to this aspect, it is possible to provide a front grill garnish with a clear parting line of the decorative layer and a three-dimensional surface. Further, in the radar performance of the on-vehicle radar device disposed behind the front grill garnish, the directivity of radio waves is increased, and an object located in the vicinity of the vehicle can be reliably detected.

  Hereinafter, embodiments of the radio wave transmitting cover member of the present invention will be described with reference to the drawings. In this embodiment, the radio wave transmitting cover member of the present invention is applied to a front grill garnish of an automobile.

(Embodiment 1)
The front grill garnish 1 of this embodiment shown in FIG. 1 and FIG. 2 is a radio wave transmission opening formed in a front grill 2 which is an exterior part of an automobile, as shown in FIG. It is arranged in the opening 2a by a fixing means such as a bracket or a bolt (not shown) so as to close the portion 2a. Further, behind the front grill garnish 1, a millimeter wave radar device 3 as an in-vehicle radar device is disposed at a position separated from the back surface of the front grill garnish 1 by a predetermined distance. The millimeter wave radar device 3 includes a transmission / reception antenna (not shown) that transmits / receives a millimeter wave having a frequency of 76.5 GHz.

  The front grill garnish 1 can transmit millimeter waves transmitted and received by the millimeter wave radar device 3, and the front transparent layer 4 disposed on the front side of the front grill 2 (on the left side of FIG. 1 outside the automobile). And a back base layer 5 disposed on the back side of the front grill 1, that is, on the millimeter wave radar device 3 side, and a decorative layer 6 disposed between the front transparent layer 4 and the back base layer 5. It has a structure in which the front side transparent layer 4, the decorative layer 6, and the back side base material layer 5 are laminated in this order from the front side of the front grill 2. The front grill garnish 1 has a biconvex lens shape as a whole.

  The front transparent layer 4 is made of PC (polycarbonate) as a transparent radio wave transmitting material (dielectric material). As shown in FIG. 2, an exploded sectional view of the front grill garnish 1, the front transparent layer 4 has a plano-convex lens shape that is convex on the front side, and the entire surface on the front side has a predetermined curvature. A convex lens surface (convex curved surface) 41 having a flat surface 42 is formed on the entire back surface on the back side. A concave portion 42a having a predetermined shape is formed at a predetermined position on the substantially flat surface 42 on the back side.

  The back-side base material layer 5 is made of AES (acrylonitrile / ethylene propylene / styrene polymer) as a radio wave transmitting material (dielectric material). The back-side base material layer 5 has a plano-convex lens-like overall shape that is convex on the back side, the entire back side of the back side is a convex lens surface (convex curved surface) 51 having a predetermined curvature, and the entire surface on the front side is flat. It consists of the substantially flat surface 52 of a shape. A convex portion 52a having a position and shape corresponding to the concave portion 42a is formed on the substantially flat surface 52 on the front side.

  The decorative layer 6 is a printing layer made of a metal thin film 61 formed by indium vapor deposition on the entire surface of the back-side base material layer 5 and a black acrylic paint formed in a predetermined shape on the metal thin film 61 at a predetermined position. 62. The printed layer 62 is formed on a portion other than the convex portion 52 a formed on the substantially flat surface 52 of the back-side base material layer 5. For this reason, when the front grill garnish 1 is viewed from the front side, silver having a metallic luster due to the metal thin film 61 formed on the convex portion 52 a is floated in the front side transparent layer 4 against the black color of the printed layer 62. It looks three-dimensional like going up.

Here, the metal thin film 61 constituting the decorative layer 6 is made of indium having a particularly high radio wave transmittance in metal. The printing layer 62 constituting the decorative layer 6 is made of an acrylic paint as a radio wave transmissive material. Furthermore, the metal thin film 61 and the printed layer 62 are both extremely thin compared to the front side transparent layer 4 and the back side base material layer 5. Therefore, the influence of the decorative layer 6 on the millimeter wave transmittance in the front grill garnish 1 can be almost ignored. And PC which comprises the front side transparent layer 4, and AES which comprises the back side base material layer 5 have a substantially equivalent relative dielectric constant (epsilon) (= 2.6). For this reason, the relative dielectric constant of the entire front grill garnish 1 is also approximately ε, and the transmission speed of the millimeter wave passing through the front grill garnish 1 is approximately ε ^−1/2 .

  The front grill garnish 1 of the present embodiment having the above-described configuration can be manufactured as follows, for example. First, the front side transparent layer 4 and the back side base material layer 5 are each formed into a predetermined shape by injection molding. Then, indium vapor deposition is performed on the entire surface of the back-side base material layer 5 to form a metal thin film 61. Thereafter, the printing layer 62 is formed on the metal thin film 61 by a printing technique called screen printing. Finally, the back side base material layer 5 and the front side transparent layer 4 on which the decorative layer 6 is formed with an adhesive are pasted to complete the front grill garnish 1 of this embodiment.

  Therefore, in the front grill garnish 1, the front side transparent layer 4 has a plano-convex lens shape that is convex on the front side. Therefore, the surface on the back side (decorative layer side) of the front side transparent layer 4 maintains flatness. It is a substantially flat surface 42. According to the front side transparent layer 4 having the plano-convex lens shape as described above, the front side convex lens surface 41 of the front side transparent layer 4 is largely curved while maintaining the flatness of the back side surface of the front side transparent layer 4 to obtain a larger curvature. It can be a convex curved surface. And if the surface of the back side of the front side transparent layer 4 maintains flatness and is a substantially flat surface 42, flatness can be maintained without curving the decorative layer 6 itself, and the printing technique is performed well. Thus, the print layer 62 can be accurately formed. Therefore, while avoiding the problem that the parting line of the decorative layer 6 becomes unclear, the surface of the front transparent layer 4 can be a convex curved surface with a larger curvature, and the design enhances the three-dimensional effect on the surface. It becomes possible to respond to the request.

  Further, in the front grill garnish 1, the front transparent layer 4 has a plano-convex lens shape, and the back-side base material layer 5 has a plano-convex lens shape, and has a biconvex lens shape as a whole. For this reason, the radio wave transmitted through the front grill garnish 1 can be largely refracted and focused with a short focal length. For this reason, since the millimeter wave transmitted from the millimeter wave radar device 3 can be sharply focused by the front grill garnish 1, the directivity of the millimeter wave is improved, and an object located near the front grill garnish 1, that is, It is possible to reliably detect an object in the vicinity of the vehicle front.

  Therefore, according to the present embodiment, it is possible to provide the front grill garnish 1 in which the parting line of the decorative layer 6 is clear and the surface is more three-dimensional. Further, in the radar performance of the millimeter wave radar device 3 disposed behind the front grill garnish 1, the directivity of the millimeter wave is increased so that an object located in the vicinity of the vehicle can be reliably detected. become.

  Further, in the front grill garnish 1 of the present embodiment, the front side transparent layer 4 and the back side base material layer 5 can reliably ensure the rigidity necessary for the cover member. Moreover, since the decoration layer 6 is arrange | positioned between the front side transparent layer 4 and the back side base material layer 5, the designability can be improved by forming this decoration layer 6 in a predetermined shape. Furthermore, the decorative layer 6 can be protected by the front side transparent layer 4 coated on the decorative layer 6, and the stereoscopic effect of the decorative layer 6 can be enhanced.

  The millimeter wave reflected by the object passes through the front grill garnish 1 again and is received by the millimeter wave radar device 3. Also at the time of reception, the millimeter wave that passes through the front grill garnish 1 is focused. For this reason, the receiving surface of the millimeter wave radar device 3 can be reduced, and as a result, the millimeter wave radar device 3 can be reduced in size.

  In this embodiment, the front transparent garnish 1 and the back base material layer 5 constituting the front grill garnish 1 are each formed as a plano-convex lens, and the entire front grill garnish 1 is formed as a biconvex lens. Only a central portion or the like of the front grill garnish may be partially formed in a convex lens shape by providing a uniform thick portion or the like on the peripheral portion or the like of the garnish 1. Further, the number of convex lenses provided partially on the front grill garnish is not limited to one, and a plurality of shapes may be provided.

(Embodiment 2)
In the present embodiment, the shape of the back base material layer 5 is changed in the front grill garnish 1 of the first embodiment.

  That is, as shown in FIG. 3, the back side base material layer 5 has a substantially flat overall shape, and the entire back side of the back side is a flat flat surface 53. Note that the entire surface on the front side of the back-side base material layer 5 is composed of a substantially flat surface 52 as in the first embodiment.

  Therefore, in the front grill garnish 1, only the front transparent layer 4 has a plano-convex lens shape, and has a plano-convex lens shape as a whole.

  Therefore, the front grill garnish 1 of the present embodiment has a longer focal length when the transmitted millimeter waves are converged than the case of the first embodiment in which the entire front grill garnish 1 has a biconvex lens shape. Further, it is possible to reduce the thickness of the front grill garnish 1 particularly in the central portion.

  Other configurations and operational effects are the same as those of the first embodiment.

(Embodiment 3)
In the present embodiment, the shape of the back base material layer 5 is changed in the front grill garnish 1 of the first embodiment.

  That is, as shown in FIG. 4, the back-side base material layer 5 has a substantially flat overall shape, and has a focusing lens function for focusing the millimeter wave transmitted through the entire back side by refraction. It consists of a lens surface 54.

  For this reason, the front grill garnish 1 has a plano-convex lens shape as a whole.

  Accordingly, the front grill garnish 1 has a biconvex lens shape as a whole of the front grill garnish 1 because the front transparent layer 4 has a plano-convex lens shape and the back base layer 5 has a Fresnel lens shape having a focusing lens function. The same lens function as in the first embodiment is provided, the focal length is shortened as in the first embodiment, and an object located closer to the front grill garnish 1 can be reliably detected. It becomes.

  Further, since the Fresnel lens shape does not increase the wall thickness unlike the convex lens shape, the front grill garnish 1 is compared with the case of the first embodiment in which the back-side base material layer 5 is a plano-convex lens shape. It is possible to reduce the thickness especially in the central part.

  Other configurations and operational effects are the same as those of the first embodiment.

(Other aspects)
In the above-described embodiment, the example in which the millimeter wave radar device 3 is separately provided at a position separated from the rear surface of the front grill garnish 1 by a predetermined distance has been described. However, the present invention is not limited thereto. is not. For example, the front opening of a box-like case having a front opening that is open on the front is covered with the back of the front grill garnish 1, or the front is made of a radio wave transmitting material (dielectric material) that can transmit radio waves. The front grill garnish 1 and the case are integrally coupled to each other by pasting the back surface of the front grill garnish 1 to the front surface of the case, and a transmission / reception antenna having a function necessary as a radar device in the case Etc. may be incorporated.

  In the above-described embodiment, an example of millimeter waves as radio waves has been described. However, a radar apparatus using radio waves other than millimeter waves, for example, microwaves may be used.

  Furthermore, in the said embodiment, although synthetic resin was employ | adopted for the front side transparent layer and the back side base material layer, glass can also be used instead of a synthetic resin.

  In addition, as a decorative layer, a metal plating layer or a metal foil may be attached instead of metal deposition. Moreover, metals other than indium may be used.

It is sectional drawing which concerns on Embodiment 1 of this invention, and shows the state which attached the front grille garnish to the vehicle. FIG. 3 is an exploded cross-sectional view illustrating a state in which the front grill garnish is disassembled according to the first embodiment of the present invention. It is sectional drawing which concerns on Embodiment 2 of this invention, and shows the state which attached the front grille garnish to the vehicle. It is sectional drawing which concerns on Embodiment 3 of this invention, and shows the state which attached the front grille garnish to the vehicle.

Explanation of symbols

1 ... Front grille garnish (radio wave permeable cover member)
2. Front grill (exterior parts)
2a ... opening 3 ... millimeter wave radar device 4 ... front side transparent layer 5 ... back side base material layer 6 ... decorative layer 41, 51 ... convex lens surface 42, 52 ... substantially flat surface 54 ... Fresnel lens surface 61 ... metal thin film 62 ... Print layer

Claims (4)

A radio wave transmissive cover member that is disposed in the opening so as to close an opening formed in an exterior part on which a radar device is disposed behind, and is capable of transmitting radio waves transmitted and received by the radar device. ,
A front side transparent layer disposed on the front side of the exterior part, a back side base material layer disposed on the back side of the exterior part, a decorative layer disposed between the front side transparent layer and the back side base material layer, With
The radio wave transmitting cover member, wherein at least a part of the front transparent layer has a plano-convex lens shape convex toward the front side.   2. The radio wave transmitting cover member according to claim 1, wherein at least a part of the back side base material layer has a plano-convex lens shape that is convex on the back side.   2. The radio wave transmissive cover member according to claim 1, wherein at least a part of the back side base material layer is formed of a Fresnel lens surface having a focusing lens function for focusing a radio wave to be transmitted by refraction.   4. The radio wave transmitting device according to claim 1, wherein the exterior component is a front grill as a vehicle exterior component, and is a front grill garnish disposed in the opening of the front grill. Cover member.

Images