WO2023067907A1 - Radome for on-board radar - Google Patents

Radome for on-board radar Download PDF

Info

Publication number
WO2023067907A1
WO2023067907A1 PCT/JP2022/032880 JP2022032880W WO2023067907A1 WO 2023067907 A1 WO2023067907 A1 WO 2023067907A1 JP 2022032880 W JP2022032880 W JP 2022032880W WO 2023067907 A1 WO2023067907 A1 WO 2023067907A1
Authority
WO
WIPO (PCT)
Prior art keywords
radome
island
shaped metal
base material
metal regions
Prior art date
Application number
PCT/JP2022/032880
Other languages
French (fr)
Japanese (ja)
Inventor
加藤卓
古林宏之
山本真平
Original Assignee
三恵技研工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三恵技研工業株式会社 filed Critical 三恵技研工業株式会社
Publication of WO2023067907A1 publication Critical patent/WO2023067907A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
    • C23C18/16—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating by reduction or substitution, e.g. electroless plating
    • C23C18/31—Coating with metals
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/14—Reflecting surfaces; Equivalent structures

Definitions

  • the present invention relates to a radome for an in-vehicle radar device provided on the front side of the in-vehicle radar device.
  • a radome provided on the front side of an in-vehicle radar device
  • a radome in which a discontinuous metal film, which is an aggregate of island-shaped metal regions divided by cracks, is provided on the surface of an insulating resin base material.
  • the discontinuous metal film composed of island-shaped metal regions divided by cracks and the insulating resin base material can provide the electromagnetic wave permeability required for the radome, and the island-shaped Visibility of metallic luster can be obtained by a discontinuous metal film of aggregates of metal regions (see Patent Documents 1 and 2).
  • each island-shaped metal region (fine metal region) constituting the discontinuous metal film has substantially the same size and shape. It is preferred to
  • the island-shaped metal regions (fine metal regions) have approximately the same size and shape, the respective island-shaped metal regions (fine metal regions) It is not clear to what degree of uniformity the radome for a vehicle-mounted radar device can be manufactured and practical electromagnetic wave permeability can be obtained.
  • the present invention is proposed in view of the above problems, and is capable of reliably producing a radome having a discontinuous metal film, which is an aggregate of island-shaped metal regions, and reliably exhibiting practical electromagnetic wave permeability. It is an object of the present invention to provide a radome for an in-vehicle radar device capable of
  • a radome for an in-vehicle radar device is provided on the front side of an in-vehicle radar device by laminating and fixing a discontinuous metal film, which is an aggregate of island-shaped metal regions separated from each other, on one surface of an insulating base material. wherein the island-shaped metal regions have an average area of 10,000 nm 2 to 80,000,000 nm 2 and a coefficient of variation of the area of the island-shaped metal regions is 0.5. ⁇ 1.5. According to this, by setting the average area of the island-shaped metal region to 80,000,000 nm2 or less, the size of the island-shaped metal region is made sufficiently smaller than the wavelength of the electromagnetic wave of the on-vehicle radar device, and the required electromagnetic wave transmission is achieved.
  • the coefficient of variation of the area of the island-like metal region can be 1.5 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -3.0 dB (approximately 50%), which is practical. electromagnetic wave permeability can be reliably exhibited. Also, by setting the coefficient of variation of the area of the island-shaped metal regions to 0.5 or more, it is possible to reliably manufacture a radome having a discontinuous metal film that is an aggregate of the island-shaped metal regions.
  • the radome for a vehicle-mounted radar device of the present invention is characterized in that the island-shaped metal regions have a coefficient of variation of area within a range of 0.5 to 1.0. According to this, by setting the coefficient of variation of the area of the island-like metal region to 1.0 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -1.0 dB (approximately 80%). , the practical electromagnetic wave permeability can be exhibited more reliably.
  • the radome for a vehicle-mounted radar device of the present invention is characterized in that the average area of the island-shaped metal regions is in the range of 20,000 nm 2 to 80,000,000 nm 2 .
  • the difference between the maximum value and the minimum value of the b* value that indicates the strength of the color in the L*a*b* color system is 1 If the value is 0.5 or more, the difference in color of the discontinuous metal film depending on the individual is likely to be visually recognized during mass production .
  • the difference between the value and the minimum value can be less than 1.5, and the difference in color of the discontinuous metal film depending on the individual can be suppressed to an invisible level.
  • the radome for a vehicle-mounted radar device of the present invention can be reliably manufactured as a radome having a discontinuous metal film, which is an aggregate of island-shaped metal regions, and can reliably exhibit practical electromagnetic wave permeability. .
  • FIG. 2 is an explanatory diagram showing the positional relationship between the radome for the vehicle-mounted radar device of the embodiment and the vehicle-mounted radar device.
  • Explanatory drawing of the measuring apparatus which measured the electromagnetic wave transmittance
  • 7 is a graph showing the relationship between the coefficient of variation, the electromagnetic wave transmittance, and the electrical conductivity of the discontinuous metal film of the radome for an in-vehicle radar device of the experimental example.
  • FIG. 2 is an explanatory diagram showing the positional relationship between the radome for the vehicle-mounted radar device of the embodiment and the vehicle-mounted radar device.
  • Explanatory drawing of the measuring apparatus which measured the electromagnetic wave transmittance
  • 7 is a graph showing the relationship between the coefficient of variation, the electromagnetic wave transmit
  • 2 is a diagram showing an example of a radome for an in-vehicle radar device that is visually recognized from the measurement unit of the color tone measurement device; 7 is a graph showing the relationship between the area of the island-shaped metal region and the b* value in the radome for an in-vehicle radar device of the experimental example.
  • a radome 1 for a vehicle-mounted radar device constitutes, for example, a bumper.
  • the electromagnetic waves EW of the in-vehicle radar device 10, which is configured by laminating and fixing discontinuous metal films 3, which are aggregates of divided and mutually separated island-shaped metal regions 31, for example, irradiating electromagnetic waves of 76 to 77 GHz. is provided on the front side, which is the irradiation side of the Furthermore, in the radome 1 of the illustrated example, another insulating base 4 is provided on one side of the insulating base 2 so as to cover the discontinuous metal film 3, in other words, to cover each island-shaped metal region 31. Another insulating substrate 4 is attached to the insulating substrate 2 at the cracks 32 and to the island-shaped metal regions 31 .
  • the insulating base material 2 and another insulating base material 4 are insulative and have electromagnetic wave permeability.
  • the insulating base material 2 and another insulating base material 4 are made of the same material, for example, so that the refractive index n defined based on the complex dielectric constant matches each other, or the refractive indices n are substantially the same or close to each other. From the viewpoint of improving the transmission performance of electromagnetic waves, it is preferable to use a material that does.
  • the difference in refractive index between the insulating base material 2 and another insulating base material 4 is within a range of 0 to 10%. is.
  • the refractive index n is a quantity defined by Equation 1 from the real part of relative permittivity ⁇ r′ and the imaginary part of relative permittivity ⁇ r′′.
  • the loss tangent tan ⁇ defined as 2 is preferably 0.1 or less, and the real part of the relative permittivity is preferably 3 or less.Dielectric loss tangent and relative permittivity By setting the real part size to these values or less, it is possible to ensure the reflectivity and internal loss reduction required for the radome.
  • the insulating base material 2 and another insulating base material 4 can be made of suitable materials within the scope of the present invention, such as synthetic resin, glass, ceramics, etc., but preferably insulating synthetic resin.
  • At least one of the insulating base material 2 and another insulating base material 4 on the visible side is formed of a transparent or translucent material in order to ensure visibility with respect to the discontinuous metal film 2.
  • the transparent or translucent material is preferably a colorless or colored material having a visible light transmittance of 50% or more in order to ensure good visibility.
  • Both the insulating base material 2 and the separate insulating base material 4 may be made of a transparent or translucent material.
  • the material is appropriate within the applicable range, such as polycarbonate.
  • PC polycarbonate
  • acrylic resins such as polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), acrylonitrile-styrene copolymer (AS), polystyrene (PS), cycloolefin polymer (COP), etc.
  • PC polycarbonate.
  • acrylic resins such as polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), acrylonitrile-styrene copolymer (AS), polystyrene (PS), cycloolefin polymer (COP), etc.
  • the material is appropriate within the applicable range,
  • acrylonitrile-ethylene propyl rubber-styrene copolymer AES
  • acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene-acrylate copolymer Polymerization (ASA)
  • PMMA polymethyl methacrylate
  • PC polycarbonate
  • ABS acrylonitrile-butadiene-styrene copolymer
  • ASA acrylonitrile-styrene-acrylate copolymer Polymerization
  • an insulating base material 2 is made of transparent and insulating synthetic resin such as polycarbonate, and another insulating base material 4 is made of non-translucent and insulating synthetic resin such as AES resin. ing. It should be noted that the radome for a vehicle-mounted radar device of the present invention can also be composed only of the insulating base material 2 and the discontinuous metal film 2 without providing a separate insulating base material 4 .
  • the discontinuous metal film 3 laminated and fixed to one surface of the insulating base material 2 is made up of aggregates of island-shaped metal regions 31 divided by fine cracks 32, so that it has electromagnetic wave permeability and is bright. It has an integral metallic luster and is formed on one surface of the insulating base material 2 by electroless plating, vapor deposition, sputtering, or the like.
  • This discontinuous metal film 2 or island-like metal region 31 is made of, for example, indium or an indium alloy, nickel or a nickel alloy, chromium or a chromium alloy, cobalt or a cobalt alloy, tin or a tin alloy, copper or a copper alloy, silver or a silver alloy, Palladium or palladium alloys, platinum or platinum alloys, rhodium or rhodium alloys, gold or gold alloys, aluminum or aluminum alloys, germanium or germanium alloys, zinc or zinc alloys, iron or iron alloys, or the like can be used.
  • the average area of the island-like metal regions 31 of the discontinuous metal film 3 in the radome 1 of the present embodiment is in the range of 10,000 nm 2 to 80,000,000 nm 2 , preferably 20,000 nm 2 to 80,000 nm 2 . 000,000 nm2 range.
  • the area variation coefficient of the island-like metal regions 31 of the discontinuous metal film 3 is set in the range of 0.5 to 1.5, preferably in the range of 0.5 to 1.0.
  • the island-shaped metal regions 31 are larger than the wavelength of the electromagnetic wave EW of the vehicle-mounted radar device 10 . It is possible to sufficiently reduce the size and ensure the required electromagnetic wave permeability. Furthermore, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 1.5 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -3.0 dB (approximately 50%). It is possible to reliably exhibit the appropriate electromagnetic wave permeability. Further, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 0.5 or more, the radome 1 having the discontinuous metal film 3 as an aggregate of the island-shaped metal regions 31 can be reliably manufactured.
  • the radome 1 has an electromagnetic wave transmittance of -1.0 dB (approximately 80%) for millimeter waves of 76 to 77 GHz, for example, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 1.0 or less. It is possible to more reliably exhibit practical electromagnetic wave permeability.
  • the difference between the maximum and minimum values of the b* value which indicates the intensity of the color tone (the intensity of yellowness at a positive b* value, is the intensity of yellowness)
  • the difference in color of the film 3 is easily visible, in the radome 1, by setting the average area of the island-shaped metal regions 31 to 20,000 nm2 or more, the difference between the maximum and minimum b* values can be reduced. It can be less than 1.5, and the difference in color of the discontinuous metal film 3 depending on the individual can be suppressed to an unrecognizable level.
  • a bumper was exemplified as a vehicle-mounted component to which the on-vehicle radar device radome 1 is applied.
  • it is suitable for decorative parts such as automobile emblems, front grilles, and the like.
  • a further electromagnetic wave-transmitting base material or film is laminated and fixed to the outside of the insulating base material 2, or another insulating base in the radome 1 for a vehicle-mounted radar device of the embodiment.
  • a configuration in which a further electromagnetic wave transparent base material or film is laminated and fixed on the outside of the material 4 is also included in the radome for a vehicle-mounted radar device of the present invention.
  • a transparent clear coat layer may be laminated and fixed as a protective layer on the outer side of the insulating base material 2 made of a transparent insulating resin.
  • the conductivity of the discontinuous metal film 3 is strongly affected by the size and amount of cracks between the island-like metal regions 31 . This is because the electrical conductivity of the cracks is significantly lower than that of the island-like metal regions 31, so that the electrical conductivity of the entire film depends on the electrical conductivity of the cracks rather than the material. Since the electromagnetic wave transmittance depends on the electrical conductivity, it is strongly affected by the structure of the discontinuous metal film 3. If the structure is the same, the transmittance will be the same even if the materials are different. In other words, the relationship between the coefficient of variation and the millimeter wave transmittance holds regardless of the material of the discontinuous metal film 3 .
  • the radome 1a shown in FIG. 3 was prepared as a sample of the radome for the vehicle-mounted radar device of the embodiment of the present invention and the radome for the vehicle-mounted radar device of the comparative example, and the electromagnetic wave transmittance was measured using the radome 1a. did In the radome 1a, a discontinuous metal film 3a, which is an aggregate of island-shaped metal regions 31a divided by fine cracks 32a, is adhered to one surface of an insulating base material 2a having electromagnetic wave permeability so as to be laminated. formed.
  • the insulating base material 2a of the radome 1a is made of transparent synthetic resin polycarbonate, and is a rectangular flat plate measuring 70 mm long, 150 mm wide, and 3 mm thick.
  • the polycarbonate insulating base material 2a has a complex dielectric constant ⁇ r' of 2.8 and a dielectric loss tangent tan ⁇ of 0.01 with respect to electromagnetic waves (millimeter waves) in the 76/77 GHz band at room temperature (approximately 25° C.).
  • the island-shaped metal regions 31a of the discontinuous metal film 3a in the radome 1a are made of indium and formed by sputtering on one surface of the insulating substrate 2a.
  • the film thickness of the discontinuous metal film 3a in the radome 1a of each sample is in the range of 20 nm to 60 nm.
  • the number of island-shaped metal regions 31a is set to be in the range of 12,500 to 200,000,000, and the average area of the island-shaped metal regions 31a is set to be 5,000 nm 2 to 80,000,000 nm 2 . It was confirmed by image analysis processing (image analysis software used: Image J (manufactured by National Institutes of Health)).
  • the electromagnetic wave transmittance of the radome 1a was measured using a Quality Automobile Radome Tester (QAR) manufactured by ROHDE & SCHWARZ as a measuring device.
  • QAR Quality Automobile Radome Tester
  • 101 is an electromagnetic wave transmitter
  • 102 is a receiver
  • 103 is an evaluation device for calculating and obtaining the measurement result of the electromagnetic wave transmittance.
  • the electromagnetic wave EW transmitted from the electromagnetic wave transmission unit 101 used for the measurement is a millimeter wave in the 76/77 GHz band, and is transmitted from the discontinuous metal film 3a side of the radome 1a to the insulating base material 2a in the propagation direction indicated by the dotted arrow in the figure. , the electromagnetic wave EW was applied to the radome 1a.
  • the electromagnetic wave transmittance of the radome 1a for millimeter waves of 76/77 GHz is ⁇ 3.0 dB (approximately 50%). I know what I can do. Furthermore, it can be seen that the electromagnetic wave transmittance of the radome 1a for millimeter waves of 76/77 GHz can be reduced to -1.0 dB (approximately 80%) by setting the area variation coefficient of the island-like metal regions 31a to 1.0 or less.
  • the coefficient of variation of the area of the island-like metal regions 31a, which are aggregates of the discontinuous metal films 3a to 1.5 or less, preferably 1.0 or less. It is possible to obtain a radome 1a that exhibits. Further, from the measurement results of FIG. 4, as the coefficient of variation increases, the conductivity increases and the transmittance decreases. It can be seen that the electromagnetic wave transmittance changes as the conductivity changes. Therefore, it can be said that the relationship between the variation coefficient and the millimeter wave transmittance holds regardless of the material of the discontinuous metal film 3a.
  • a radome 1b shown in FIG. 5 was prepared as a sample of the radome for the vehicle-mounted radar system of the embodiment of the present invention and the radome for the vehicle-mounted radar system of the comparative example, and a measurement test was conducted to measure the color tone of the radome 1b.
  • a discontinuous metal film 3b which is an aggregate of island-shaped metal regions 31b divided by fine cracks 32b, is laminated on one surface of an insulating base material 2b having electromagnetic wave permeability.
  • another insulating base material 4b is provided so as to cover each island-shaped metal region 31b of the discontinuous metal film 3b on one surface side of the insulating base material 2b, and the another insulating base material 4 is provided with cracks 32b. It is fixed to the insulating base material 2b at the point , and is also fixed to the island-shaped metal region 31b.
  • the insulating base material 2b of the radome 1b is made of transparent synthetic resin polycarbonate, and is a rectangular flat plate measuring 70 mm long, 150 mm wide and 3 mm thick.
  • the visible light transmittance in the thickness direction of the radome 1b made of transparent polycarbonate is 89%.
  • Another insulating base material 4b of the radome 1b is made of a non-translucent AES resin, and is a rectangular flat plate measuring 70 mm long, 150 mm wide and 3 mm thick.
  • the island-shaped metal regions 31b of the discontinuous metal film 3b in the radome 1b are made of indium, and are formed by sputtering on one surface of the insulating substrate 2b.
  • the film thickness of the discontinuous metal film 3b in the radome 1b of each sample is in the range of 20 nm to 60 nm.
  • the number of 31b is in the range of 12,500 to 200,000,000, and the area variation coefficient of the island-like metal regions 31b of the discontinuous metal film 3b is in the range of 0.5 to 1.5. This state was confirmed by image analysis processing for the radome 1b (image analysis software used: Image J (manufactured by National Institutes of Health)).
  • the color tone of the radome 1b was measured using a spectrophotometer (CM-3700d) manufactured by Konica Minolta as the color tone measuring device 200 .
  • Reference numeral 201 in the color tone measuring apparatus 200 of FIG. 5 is a measuring section, which is an opening for the sample.
  • FIG. 6 is an example of the radome 1b viewed from the opening measuring part 201.
  • the average areas of the island-shaped metal regions 31b are set to about 10,000 nm 2 , about 20,000 nm 2 , about 30,000 nm 2 , about 40,000 nm 2 , and about 85,000 nm 2 .
  • the difference between the maximum and minimum b* values is 1.87 .
  • the difference between the maximum and minimum b* values is 1.31 .
  • the difference between the maximum and minimum b* values when the average area of the island-shaped metal regions 31b is about 40,000 nm2 is 1.08, and when the average area of the island-shaped metal regions 31b is about 85,000 nm2 , b
  • the difference between the maximum value and the minimum value of * is about 0.13, and the larger the average area of the island-like metal regions 31b, the smaller the variation in the b* value.
  • the difference between the maximum and minimum values of b* is 1.5 or more, the difference in color of the discontinuous metal film 3b depending on the individual is likely to be visually recognized during mass production.
  • the difference between the maximum and minimum b* values can be less than 1.5, and the difference in color of the discontinuous metal film 3b depending on the individual can be visually recognized. It can be seen that it can be suppressed to an impossible level.
  • the present invention can be used as a radome for an in-vehicle radar device.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Chemical & Material Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electromagnetism (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Details Of Aerials (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

This radome 1 for an on-board radar has a discontinuous metal film 3, i.e. a collective body of island-shaped metal regions 31 divided by cracks 32, laminated and fixed to one surface of an insulating substrate 2, and is disposed on the front side of an on-board radar 10, wherein the area of the island-shaped metal regions 31 is in a range of 10,000 nm2 to 80,000,000 nm2, and the area of the island-shaped metal regions 31 has a variation coefficient in a range of 0.5 to 1.5. The radome having the discontinuous metal film formed from the collective body of the island-shaped metal regions can be reliably manufactured, and practical electromagnetic wave permeability can be reliably exerted.

Description

車載レーダー装置用レドームRadome for in-vehicle radar equipment
　本発明は、車載レーダー装置の前側に設けられる車載レーダー装置用レドームに関する。 The present invention relates to a radome for an in-vehicle radar device provided on the front side of the in-vehicle radar device.
　従来、車載レーダー装置の前側に設けられるレドームとして、クラックで分割された島状金属領域の集合体である不連続金属膜が絶縁性の樹脂基材の表面に設けられるレドームが知られている。このようなレドームでは、クラックで分割された島状金属領域で構成される不連続金属膜、絶縁性の樹脂基材により、レドームとして必要とされる電磁波透過性を得ることができると共に、島状金属領域の集合体の不連続金属膜により、金属光沢の視認性を得ることができる（特許文献１、２参照）。 Conventionally, as a radome provided on the front side of an in-vehicle radar device, a radome is known in which a discontinuous metal film, which is an aggregate of island-shaped metal regions divided by cracks, is provided on the surface of an insulating resin base material. In such a radome, the discontinuous metal film composed of island-shaped metal regions divided by cracks and the insulating resin base material can provide the electromagnetic wave permeability required for the radome, and the island-shaped Visibility of metallic luster can be obtained by a discontinuous metal film of aggregates of metal regions (see Patent Documents 1 and 2).
　そして、特許文献１、２では、より良好な電磁波透過性を得る観点から、不連続金属膜を構成する各々の島状金属領域（微細金属領域）は、略同じ大きさで、略同じ形状とすることが好ましいとされている。 In Patent Documents 1 and 2, from the viewpoint of obtaining better electromagnetic wave permeability, each island-shaped metal region (fine metal region) constituting the discontinuous metal film has substantially the same size and shape. It is preferred to
特開２０１５－３８２５４号公報JP 2015-38254 A 特開２０１５－１１０８３６号公報JP 2015-110836 A
　ところで、特許文献１、２では、島状金属領域（微細金属領域）を略同じ大きさで、略同じ形状とすることが好ましいとされているものの、それぞれの島状金属領域（微細金属領域）が具体的にどの程度の均一性を有する場合に、車載レーダー装置用レドームとして製造可能であり、且つ実用的な電磁波透過性が得られるのかが定かではない。 By the way, in Patent Documents 1 and 2, although it is preferable that the island-shaped metal regions (fine metal regions) have approximately the same size and shape, the respective island-shaped metal regions (fine metal regions) It is not clear to what degree of uniformity the radome for a vehicle-mounted radar device can be manufactured and practical electromagnetic wave permeability can be obtained.
　本発明は上記課題に鑑み提案するものであって、島状金属領域の集合体である不連続金属膜を有するレドームとして確実に製造することができると共に、実用的な電磁波透過性を確実に発揮することができる車載レーダー装置用レドームを提供することを目的とする。 The present invention is proposed in view of the above problems, and is capable of reliably producing a radome having a discontinuous metal film, which is an aggregate of island-shaped metal regions, and reliably exhibiting practical electromagnetic wave permeability. It is an object of the present invention to provide a radome for an in-vehicle radar device capable of
　本発明の車載レーダー装置用レドームは、絶縁基材の一方の面に相互に分離された島状金属領域の集合体である不連続金属膜が積層して固着され、車載レーダー装置の前側に設けられる車載レーダー装置用レドームであって、前記島状金属領域の平均面積が１０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲にあると共に、前記島状金属領域の面積の変動係数が０．５～１．５の範囲にあることを特徴とする。
　これによれば、島状金属領域の平均面積を８０，０００，０００ｎｍ２以下とすることにより、車載レーダー装置の電磁波の波長よりも島状金属領域のサイズを十分に小さくし、所要の電磁波透過性を確保することが可能となる。更に、島状金属領域の面積の変動係数を１．５以下とすることにより、例えば７６～７７ＧＨｚのミリ波に対する電磁波透過率を－３．０ｄＢ（約５０％）とすることができ、実用的な電磁波透過性を確実に発揮することができる。また、島状金属領域の面積の変動係数を０．５以上とすることにより、島状金属領域の集合体である不連続金属膜を有するレドームを確実に製造することができる。 A radome for an in-vehicle radar device according to the present invention is provided on the front side of an in-vehicle radar device by laminating and fixing a discontinuous metal film, which is an aggregate of island-shaped metal regions separated from each other, on one surface of an insulating base material. wherein the island-shaped metal regions have an average area of 10,000 nm 2 to 80,000,000 nm 2 and a coefficient of variation of the area of the island-shaped metal regions is 0.5. ∼1.5.
According to this, by setting the average area of the island-shaped metal region to 80,000,000 nm2 or less, the size of the island-shaped metal region is made sufficiently smaller than the wavelength of the electromagnetic wave of the on-vehicle radar device, and the required electromagnetic wave transmission is achieved. It becomes possible to ensure the reliability. Furthermore, by setting the coefficient of variation of the area of the island-like metal region to 1.5 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -3.0 dB (approximately 50%), which is practical. electromagnetic wave permeability can be reliably exhibited. Also, by setting the coefficient of variation of the area of the island-shaped metal regions to 0.5 or more, it is possible to reliably manufacture a radome having a discontinuous metal film that is an aggregate of the island-shaped metal regions.
　本発明の車載レーダー装置用レドームは、前記島状金属領域の面積の変動係数が０．５～１．０の範囲にあることを特徴とする。
　これによれば、島状金属領域の面積の変動係数を１．０以下とすることにより、例えば７６～７７ＧＨｚのミリ波に対する電磁波透過率を－１．０ｄＢ（約８０％）とすることができ、実用的な電磁波透過性をより確実に発揮することができる。 The radome for a vehicle-mounted radar device of the present invention is characterized in that the island-shaped metal regions have a coefficient of variation of area within a range of 0.5 to 1.0.
According to this, by setting the coefficient of variation of the area of the island-like metal region to 1.0 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -1.0 dB (approximately 80%). , the practical electromagnetic wave permeability can be exhibited more reliably.
　本発明の車載レーダー装置用レドームは、前記島状金属領域の平均面積が２０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲にあることを特徴とする。
　これによれば、Ｌ*ａ*ｂ*表色系において色味の強弱を示すｂ*値（ｂ*値のプラス値での強弱は黄色味の強弱）の最大値と最小値の差が１．５以上になると、量産時に個体による不連続金属膜の色の違いが視認され易くなってしまうが、島状金属領域の平均面積を２０，０００ｎｍ２以上とすることにより、ｂ*値の最大値と最小値の差を１．５未満とすることができ、個体による不連続金属膜の色の違いを視認できないレベルに抑えることができる。 The radome for a vehicle-mounted radar device of the present invention is characterized in that the average area of the island-shaped metal regions is in the range of 20,000 nm 2 to 80,000,000 nm 2 .
According to this, the difference between the maximum value and the minimum value of the b* value that indicates the strength of the color in the L*a*b* color system (the strength of the b* value with a positive value is the strength of yellowness) is 1 If the value is 0.5 or more, the difference in color of the discontinuous metal film depending on the individual is likely to be visually recognized during mass production . The difference between the value and the minimum value can be less than 1.5, and the difference in color of the discontinuous metal film depending on the individual can be suppressed to an invisible level.
　本発明の車載レーダー装置用レドームは、島状金属領域の集合体である不連続金属膜を有するレドームとして確実に製造することができると共に、実用的な電磁波透過性を確実に発揮することができる。 INDUSTRIAL APPLICABILITY The radome for a vehicle-mounted radar device of the present invention can be reliably manufactured as a radome having a discontinuous metal film, which is an aggregate of island-shaped metal regions, and can reliably exhibit practical electromagnetic wave permeability. .
本発明による実施形態の車載レーダー装置用レドームを示す断面図。BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the radome for vehicle-mounted radar apparatus of embodiment by this invention. 実施形態の車載レーダー装置用レドームと車載レーダー装置の配置関係を示す説明図。FIG. 2 is an explanatory diagram showing the positional relationship between the radome for the vehicle-mounted radar device of the embodiment and the vehicle-mounted radar device. 実験例の車載レーダー装置用レドームの電磁波透過率を測定した測定装置の説明図。Explanatory drawing of the measuring apparatus which measured the electromagnetic wave transmittance|permeability of the radome for the vehicle-mounted radar apparatus of the experimental example. 実験例の車載レーダー装置用レドームの変動係数と電磁波透過率と不連続金属膜の導電率との関係を示すグラフ。7 is a graph showing the relationship between the coefficient of variation, the electromagnetic wave transmittance, and the electrical conductivity of the discontinuous metal film of the radome for an in-vehicle radar device of the experimental example. 実験例の車載レーダー装置用レドームの色調測定装置の説明図。Explanatory drawing of the color tone measuring apparatus of the radome for the vehicle-mounted radar apparatus of the experimental example. 色調測定装置の測定部から視認される車載レーダー装置用レドームの例を示す図。FIG. 2 is a diagram showing an example of a radome for an in-vehicle radar device that is visually recognized from the measurement unit of the color tone measurement device; 実験例の車載レーダー装置用レドームにおける島状金属領域の面積とｂ*値の関係を示すグラフ。7 is a graph showing the relationship between the area of the island-shaped metal region and the b* value in the radome for an in-vehicle radar device of the experimental example.
　〔実施形態の車載レーダー装置用レドーム〕
　本発明による実施形態の車載レーダー装置用レドーム１は、例えばバンパー等を構成するものであり、図１及び図２に示すように、絶縁基材２の一方の面に、例えば微細なクラック３２で分割されて相互に分離された島状金属領域３１の集合体である不連続金属膜３を積層するように固着して構成され、例えば７６～７７ＧＨｚの電磁波を照射する車載レーダー装置１０の電磁波ＥＷの照射側である前側に設けられる。更に、図示例のレドーム１では、絶縁基材２の一方の面側において不連続金属膜３を覆うように、換言すれば各々の島状金属領域３１を覆うように別の絶縁基材４が設けられており、別の絶縁基材４が、クラック３２の箇所で絶縁基材２に固着されていると共に、島状金属領域３１に固着されている。 [Radiome for in-vehicle radar device of embodiment]
A radome 1 for a vehicle-mounted radar device according to an embodiment of the present invention constitutes, for example, a bumper. As shown in FIGS. The electromagnetic waves EW of the in-vehicle radar device 10, which is configured by laminating and fixing discontinuous metal films 3, which are aggregates of divided and mutually separated island-shaped metal regions 31, for example, irradiating electromagnetic waves of 76 to 77 GHz. is provided on the front side, which is the irradiation side of the Furthermore, in the radome 1 of the illustrated example, another insulating base 4 is provided on one side of the insulating base 2 so as to cover the discontinuous metal film 3, in other words, to cover each island-shaped metal region 31. Another insulating substrate 4 is attached to the insulating substrate 2 at the cracks 32 and to the island-shaped metal regions 31 .
　絶縁基材２と、別の絶縁基材４は絶縁性で電磁波透過性を有する。絶縁基材２と、別の絶縁基材４には、例えば同一材料で形成する等、複素誘電率に基づき定義される屈折率ｎが相互に整合する、又は、屈折率ｎが略同一或いは近接するものを用いると電磁波の透過性能向上の観点から好適である。絶縁基材２と別の絶縁基材４の近接する屈折率ｎの数値範囲としては、絶縁基材２と別の絶縁基材４の屈折率の相違が０～１０％の範囲内とすると良好である。 The insulating base material 2 and another insulating base material 4 are insulative and have electromagnetic wave permeability. The insulating base material 2 and another insulating base material 4 are made of the same material, for example, so that the refractive index n defined based on the complex dielectric constant matches each other, or the refractive indices n are substantially the same or close to each other. From the viewpoint of improving the transmission performance of electromagnetic waves, it is preferable to use a material that does. As for the numerical range of the refractive index n in which the insulating base material 2 and another insulating base material 4 are adjacent to each other, it is preferable that the difference in refractive index between the insulating base material 2 and another insulating base material 4 is within a range of 0 to 10%. is.
　ここでの屈折率ｎは比誘電率実数部εr'と比誘電率虚数部εr"から数式１として定義される量である。 透過性の観点から適用周波数における虚数部と実数部の比から数式２として定義される誘電正接（ロスタンジェント）tanδの大きさは０．１以下とすると好適である。また比誘電率実部の大きさは３以下とすると好適である。誘電正接と比誘電率実部の大きさをこれらの数値以下とすることにより、レドームに必要とされる反射率と内部損失の低減を確実にすることが可能となる。 Here, the refractive index n is a quantity defined by Equation 1 from the real part of relative permittivity εr′ and the imaginary part of relative permittivity εr″. The loss tangent tan δ defined as 2 is preferably 0.1 or less, and the real part of the relative permittivity is preferably 3 or less.Dielectric loss tangent and relative permittivity By setting the real part size to these values or less, it is possible to ensure the reflectivity and internal loss reduction required for the radome.
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　絶縁基材２と、別の絶縁基材４は、合成樹脂、ガラス、セラミックス等の本発明の趣旨の範囲内で適宜の材料を用いることが可能であるが、好適には絶縁性の合成樹脂とするとよい。また、絶縁基材２と別の絶縁基材４の少なくとも視認される側の何れか一方は、不連続金属膜２に対する視認性を確保するために、透明或いは透光性の材料で形成するが、この透明或いは透光性の材料は、良好な視認性を確保するため可視光線透過率５０％以上の無色材料又は有色材料とすることが好ましい。尚、絶縁基材２と別の絶縁基材４の双方とも、透明或いは透光性の材料で形成してもよい。 The insulating base material 2 and another insulating base material 4 can be made of suitable materials within the scope of the present invention, such as synthetic resin, glass, ceramics, etc., but preferably insulating synthetic resin. should be At least one of the insulating base material 2 and another insulating base material 4 on the visible side is formed of a transparent or translucent material in order to ensure visibility with respect to the discontinuous metal film 2. The transparent or translucent material is preferably a colorless or colored material having a visible light transmittance of 50% or more in order to ensure good visibility. Both the insulating base material 2 and the separate insulating base material 4 may be made of a transparent or translucent material.
　絶縁基材２と別の絶縁基材４の視認される側の一方或いは双方を絶縁性の透明或いは透光性の合成樹脂とする場合の材料は、適用可能な範囲で適宜であり、例えばポリカーボネート（ＰＣ）、ポリメチルメタクリレート（ＰＭＭＡ）等のアクリル系樹脂、アクリロニトリル－ブタジエン－スチレン共重合体（ＡＢＳ）、ポリエチレンテレフタレート（ＰＥＴ）、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）、アクリロニトリル－スチレン共重合体（ＡＳ）、ポリスチレン（ＰＳ）、シクロオレフィンポリマー（ＣＯＰ）等の１種を単独でまたは２種以上を組み合わせて用いることができ、又、添加剤を含有させてもよい。 When one or both of the insulating base material 2 and the other insulating base material 4 are made of an insulating transparent or translucent synthetic resin, the material is appropriate within the applicable range, such as polycarbonate. (PC), acrylic resins such as polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene copolymer (ABS), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), acrylonitrile-styrene copolymer (AS), polystyrene (PS), cycloolefin polymer (COP), etc., may be used singly or in combination of two or more, and additives may be contained.
　絶縁基材２と別の絶縁基材４の視認される側と逆側の他方を不透明或いは非透光性で絶縁性の合成樹脂とする場合の材料は、適用可能な範囲で適宜であり、例えばアクリロニトリル－エチレンプロピルラバー－スチレン共重合体（ＡＥＳ）、ポリメチルメタクリレート（ＰＭＭＡ）等のアクリル系樹脂、ポリカーボネート（ＰＣ）、アクリロニトリル－ブタジエン－スチレン共重合体（ＡＢＳ）、アクリロニトリル－スチレン－アクリレート共重合（ＡＳＡ）等の１種を単独でまたは２種以上を組み合わせて用いることができ、又、添加剤を含有させてもよい。 When the other side of the insulating base material 2 and the other insulating base material 4 opposite to the visible side is made of an opaque or non-translucent insulating synthetic resin, the material is appropriate within the applicable range, For example, acrylonitrile-ethylene propyl rubber-styrene copolymer (AES), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene-acrylate copolymer Polymerization (ASA) can be used singly or in combination of two or more, and additives may be contained.
　図示例のレドーム１では、絶縁基材２がポリカーボネート等の透明で絶縁性の合成樹脂で形成され、別の絶縁基材４がＡＥＳ樹脂等の非透光性で絶縁性の合成樹脂で形成されている。尚、本発明の車載レーダー装置用レドームは、別の絶縁基材４を設けずに、絶縁基材２と、不連続金属膜２だけで構成することも可能である。 In the illustrated radome 1, an insulating base material 2 is made of transparent and insulating synthetic resin such as polycarbonate, and another insulating base material 4 is made of non-translucent and insulating synthetic resin such as AES resin. ing. It should be noted that the radome for a vehicle-mounted radar device of the present invention can also be composed only of the insulating base material 2 and the discontinuous metal film 2 without providing a separate insulating base material 4 .
　絶縁基材２の一方の面に積層固着された不連続金属膜３は、微細なクラック３２で分割された島状金属領域３１の集合体からなることにより、電磁波透過性を有すると共に光輝性で一体的な金属光沢の視認性を有し、絶縁基材２の一方の面に無電解めっき、蒸着又はスパッタ等で形成されている。この不連続金属膜２或いは島状金属領域３１は、例えばインジウム若しくはインジウム合金、ニッケル若しくはニッケル合金、クロム若しくはクロム合金、コバルト若しくはコバルト合金、錫若しくは錫合金、銅若しくは銅合金、銀若しくは銀合金、パラジウム若しくはパラジウム合金、白金若しくは白金合金、ロジウム若しくはロジウム合金、金若しくは金合金、アルミニウム若しくはアルミニウム合金、ゲルマニウム若しくはゲルマニウム合金、亜鉛若しくは亜鉛合金、鉄若しくは鉄合金等から構成することが可能である。 The discontinuous metal film 3 laminated and fixed to one surface of the insulating base material 2 is made up of aggregates of island-shaped metal regions 31 divided by fine cracks 32, so that it has electromagnetic wave permeability and is bright. It has an integral metallic luster and is formed on one surface of the insulating base material 2 by electroless plating, vapor deposition, sputtering, or the like. This discontinuous metal film 2 or island-like metal region 31 is made of, for example, indium or an indium alloy, nickel or a nickel alloy, chromium or a chromium alloy, cobalt or a cobalt alloy, tin or a tin alloy, copper or a copper alloy, silver or a silver alloy, Palladium or palladium alloys, platinum or platinum alloys, rhodium or rhodium alloys, gold or gold alloys, aluminum or aluminum alloys, germanium or germanium alloys, zinc or zinc alloys, iron or iron alloys, or the like can be used.
　そして、本実施形態のレドーム１における不連続金属膜３の島状金属領域３１の平均面積は、１０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲とし、好適には２０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲とする。また、不連続金属膜３の島状金属領域３１の面積の変動係数は、０．５～１．５の範囲とし、好適には０．５～１．０の範囲とする。 The average area of the island-like metal regions 31 of the discontinuous metal film 3 in the radome 1 of the present embodiment is in the range of 10,000 nm 2 to 80,000,000 nm 2 , preferably 20,000 nm 2 to 80,000 nm 2 . 000,000 nm2 range. The area variation coefficient of the island-like metal regions 31 of the discontinuous metal film 3 is set in the range of 0.5 to 1.5, preferably in the range of 0.5 to 1.0.
　本実施形態の車載レーダー装置用レドーム１は、島状金属領域３１の平均面積を８０，０００，０００ｎｍ２以下とすることにより、車載レーダー装置１０の電磁波ＥＷの波長よりも島状金属領域３１のサイズを十分に小さくし、所要の電磁波透過性を確保することが可能となる。更に、島状金属領域３１の面積の変動係数を１．５以下とすることにより、例えば７６～７７ＧＨｚのミリ波に対する電磁波透過率を－３．０ｄＢ（約５０％）とすることができ、実用的な電磁波透過性を確実に発揮することができる。また、島状金属領域３１の面積の変動係数を０．５以上とすることにより、島状金属領域３１の集合体である不連続金属膜３を有するレドーム１を確実に製造することができる。 In the vehicle-mounted radar device radome 1 of the present embodiment, by setting the average area of the island-shaped metal regions 31 to 80,000,000 nm 2 or less, the island-shaped metal regions 31 are larger than the wavelength of the electromagnetic wave EW of the vehicle-mounted radar device 10 . It is possible to sufficiently reduce the size and ensure the required electromagnetic wave permeability. Furthermore, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 1.5 or less, the electromagnetic wave transmittance for millimeter waves of 76 to 77 GHz, for example, can be reduced to -3.0 dB (approximately 50%). It is possible to reliably exhibit the appropriate electromagnetic wave permeability. Further, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 0.5 or more, the radome 1 having the discontinuous metal film 3 as an aggregate of the island-shaped metal regions 31 can be reliably manufactured.
　更に、レドーム１は、島状金属領域３１の面積の変動係数を１．０以下とすることにより、例えば７６～７７ＧＨｚのミリ波に対する電磁波透過率を－１．０ｄＢ（約８０％）とすることができ、実用的な電磁波透過性をより確実に発揮することができる。 Furthermore, the radome 1 has an electromagnetic wave transmittance of -1.0 dB (approximately 80%) for millimeter waves of 76 to 77 GHz, for example, by setting the coefficient of variation of the area of the island-shaped metal regions 31 to 1.0 or less. It is possible to more reliably exhibit practical electromagnetic wave permeability.
　また、色味の強弱を示すｂ*値（ｂ*値のプラス値での強弱は黄色味の強弱）の最大値と最小値の差が１．５以上になると、量産時に個体による不連続金属膜３の色の違いが視認され易くなってしまうが、レドーム１では、島状金属領域３１の平均面積を２０，０００ｎｍ２以上とすることにより、ｂ*値の最大値と最小値の差を１．５未満とすることができ、個体による不連続金属膜３の色の違いを視認できないレベルに抑えることができる。 In addition, if the difference between the maximum and minimum values of the b* value, which indicates the intensity of the color tone (the intensity of yellowness at a positive b* value, is the intensity of yellowness), is 1.5 or more, discontinuous metal Although the difference in color of the film 3 is easily visible, in the radome 1, by setting the average area of the island-shaped metal regions 31 to 20,000 nm2 or more, the difference between the maximum and minimum b* values can be reduced. It can be less than 1.5, and the difference in color of the discontinuous metal film 3 depending on the individual can be suppressed to an unrecognizable level.
　〔本明細書開示発明の包含範囲〕
　本明細書開示の発明は、発明として列記した各発明、実施形態の他に、適用可能な範囲で、これらの部分的な内容を本明細書開示の他の内容に変更して特定したもの、或いはこれらの内容に本明細書開示の他の内容を付加して特定したもの、或いはこれらの部分的な内容を部分的な作用効果が得られる限度で削除して上位概念化して特定したものを包含する。そして、本明細書開示の発明には下記変形例や追記した内容も含まれる。 [Scope of invention disclosed in this specification]
In addition to each invention and embodiment listed as an invention, the invention disclosed in this specification is specified by changing these partial contents to other contents disclosed in this specification within the applicable range, Alternatively, what is specified by adding other contents disclosed in this specification to these contents, or what is specified by deleting these partial contents to the extent that partial effects can be obtained and making them a broader concept contain. The invention disclosed in this specification also includes the following modifications and additional contents.
　例えば上記実施形態では、車載レーダー装置用レドーム１が適用される車両実装部品としてバンパーを例示したが、本発明の車載レーダー装置用レドームは、適宜の車両実装部品で構成することが可能であり、例えば自動車のエンブレムのような装飾部品、フロントグリル等としても良好である。 For example, in the above-described embodiment, a bumper was exemplified as a vehicle-mounted component to which the on-vehicle radar device radome 1 is applied. For example, it is suitable for decorative parts such as automobile emblems, front grilles, and the like.
　また、実施形態の車載レーダー装置用レドーム１における絶縁基材２の外側に更なる電磁波透過性の基材或いは膜を積層固着した構成や、実施形態の車載レーダー装置用レドーム１における別の絶縁基材４の外側に更なる電磁波透過性の基材或いは膜を積層固着した構成も、本発明の車載レーダー装置用レドームに包含される。例えば透明の絶縁樹脂で形成された絶縁基材２の外側に、保護層として透明なクリアコート層を積層固着しても良好である。 Further, in the radome 1 for a vehicle-mounted radar device of the embodiment, a further electromagnetic wave-transmitting base material or film is laminated and fixed to the outside of the insulating base material 2, or another insulating base in the radome 1 for a vehicle-mounted radar device of the embodiment. A configuration in which a further electromagnetic wave transparent base material or film is laminated and fixed on the outside of the material 4 is also included in the radome for a vehicle-mounted radar device of the present invention. For example, a transparent clear coat layer may be laminated and fixed as a protective layer on the outer side of the insulating base material 2 made of a transparent insulating resin.
　尚、不連続金属膜３の導電率は島状金属領域３１の間のクラックの大きさ、量の影響を強く受ける。これはクラックの導電率が島状金属領域３１の導電率よりも著しく低いため、膜全体の導電率は材料ではなくクラックの導電率に依存するためである。電磁波透過率は導電率に依存することから不連続金属膜３の構造の影響を強く受け、構造が同様であれば材料が異なる場合においても透過率は同等になる。つまり、不連続金属膜３の材料にかかわらず変動係数とミリ波透過率の関係は成立する。 The conductivity of the discontinuous metal film 3 is strongly affected by the size and amount of cracks between the island-like metal regions 31 . This is because the electrical conductivity of the cracks is significantly lower than that of the island-like metal regions 31, so that the electrical conductivity of the entire film depends on the electrical conductivity of the cracks rather than the material. Since the electromagnetic wave transmittance depends on the electrical conductivity, it is strongly affected by the structure of the discontinuous metal film 3. If the structure is the same, the transmittance will be the same even if the materials are different. In other words, the relationship between the coefficient of variation and the millimeter wave transmittance holds regardless of the material of the discontinuous metal film 3 .
　〔レドームの電磁波透過性の測定試験〕
　次に、本発明の実施例の車載レーダー装置用レドーム及び比較例の車載レーダー装置用レドームのサンプルとして、図３に示すレドーム１ａを作成し、レドーム１ａを用いて電磁波透過率を測定する測定試験を行った。レドーム１ａは、電磁波透過性を有する絶縁基材２ａの一方の面に、微細なクラック３２ａで分割された島状金属領域３１ａの集合体である不連続金属膜３ａを積層するように固着して形成した。 [Measurement test of electromagnetic wave permeability of radome]
Next, the radome 1a shown in FIG. 3 was prepared as a sample of the radome for the vehicle-mounted radar device of the embodiment of the present invention and the radome for the vehicle-mounted radar device of the comparative example, and the electromagnetic wave transmittance was measured using the radome 1a. did In the radome 1a, a discontinuous metal film 3a, which is an aggregate of island-shaped metal regions 31a divided by fine cracks 32a, is adhered to one surface of an insulating base material 2a having electromagnetic wave permeability so as to be laminated. formed.
　レドーム１ａの絶縁基材２ａは、透明合成樹脂のポリカーボネートで形成されており、縦７０ｍｍ、横１５０ｍｍ、厚さ３ｍｍの長方形の平板になっている。このポリカーボネートの絶縁基材２ａにおける室温（約２５℃）での７６／７７ＧＨｚ帯の電磁波（ミリ波）に対する複素比誘電率εr'は２．８、誘電正接tanδは０．０１である。 The insulating base material 2a of the radome 1a is made of transparent synthetic resin polycarbonate, and is a rectangular flat plate measuring 70 mm long, 150 mm wide, and 3 mm thick. The polycarbonate insulating base material 2a has a complex dielectric constant εr' of 2.8 and a dielectric loss tangent tan δ of 0.01 with respect to electromagnetic waves (millimeter waves) in the 76/77 GHz band at room temperature (approximately 25° C.).
　レドーム１ａにおける不連続金属膜３ａの島状金属領域３１ａはインジウムで形成されており、絶縁基材２ａの一方の面にスパッタリングで形成されている。各サンプルのレドーム１ａにおける不連続金属膜３ａの膜厚は２０ｎｍ～６０ｎｍの範囲にあるものとし、又、レドーム１ａの不連続金属膜３ａにおける単位面積（１ｍｍ２）当たりの微細な島状金属領域３１ａの個数は１２，５００個～２００，０００，０００個の範囲にあるものとし、島状金属領域３１ａの平均面積は５，０００ｎｍ２～８０，０００，０００ｎｍ２とし、この状態をレドーム１ａに対する画像解析処理（使用画像解析ソフトウェア：Image J(National Institutes of Health製)）で確認した。 The island-shaped metal regions 31a of the discontinuous metal film 3a in the radome 1a are made of indium and formed by sputtering on one surface of the insulating substrate 2a. The film thickness of the discontinuous metal film 3a in the radome 1a of each sample is in the range of 20 nm to 60 nm. The number of island-shaped metal regions 31a is set to be in the range of 12,500 to 200,000,000, and the average area of the island-shaped metal regions 31a is set to be 5,000 nm 2 to 80,000,000 nm 2 . It was confirmed by image analysis processing (image analysis software used: Image J (manufactured by National Institutes of Health)).
　レドーム１ａの電磁波透過率の測定は、ROHDE&SCHWARZ社製Quality Automobile Radome Tester(QAR)を測定装置として用いて実施した。この測定装置の図３において、１０１は電磁波発信部、１０２は受信部、１０３は電磁波透過率の測定結果を算出、取得する評価装置である。測定に利用した電磁波発信部１０１から送信する電磁波ＥＷは７６／７７ＧＨｚ帯のミリ波であり、図示の点線矢印の伝搬方向に、レドーム１ａの不連続金属膜３ａ側から絶縁基材２ａに抜けるように電磁波ＥＷをレドーム１ａに照射した。そして、サンプルのレドーム１ａのそれぞれにおいて、不連続金属膜３ａの島状金属領域３１ａの面積の変動係数を所定範囲で変更し、各変動係数を有するレドーム１ａの電磁波透過率を測定した。その測定結果を図４に示す。 The electromagnetic wave transmittance of the radome 1a was measured using a Quality Automobile Radome Tester (QAR) manufactured by ROHDE & SCHWARZ as a measuring device. In FIG. 3 of this measuring apparatus, 101 is an electromagnetic wave transmitter, 102 is a receiver, and 103 is an evaluation device for calculating and obtaining the measurement result of the electromagnetic wave transmittance. The electromagnetic wave EW transmitted from the electromagnetic wave transmission unit 101 used for the measurement is a millimeter wave in the 76/77 GHz band, and is transmitted from the discontinuous metal film 3a side of the radome 1a to the insulating base material 2a in the propagation direction indicated by the dotted arrow in the figure. , the electromagnetic wave EW was applied to the radome 1a. Then, in each of the sample radomes 1a, the variation coefficient of the area of the island-like metal regions 31a of the discontinuous metal film 3a was changed within a predetermined range, and the electromagnetic wave transmittance of the radome 1a having each variation coefficient was measured. The measurement results are shown in FIG.
　図４の測定結果から、島状金属領域３１ａの面積の変動係数を１．５以下とすることにより、レドーム１ａの７６／７７ＧＨｚのミリ波に対する電磁波透過率を－３．０ｄＢ（約５０％）にできることが分かる。更に、島状金属領域３１ａの面積の変動係数を１．０以下とすることにより、レドーム１ａの７６／７７ＧＨｚのミリ波に対する電磁波透過率を－１．０ｄＢ（約８０％）にできることが分かる。即ち、不連続金属膜３ａを集合体で構成する島状金属領域３１ａの面積の変動係数を１．５以下、好適には１．０以下とすることにより、実用的に十分な電磁波透過性を発揮するレドーム１ａを得ることができる。また、図４の測定結果から、変動係数の増大に伴い導電率が高くなり、透過率が低くなる、即ち不連続金属膜３ａの導電率が不連続金属膜３ａの構造に依存しており、導電率の変化に伴い電磁波透過率も変化することが分かる。従って、この変動係数とミリ波透過率の関係は不連続金属膜３ａの材料にかかわらず成立すると言える。 From the measurement results of FIG. 4, by setting the coefficient of variation of the area of the island-shaped metal region 31a to 1.5 or less, the electromagnetic wave transmittance of the radome 1a for millimeter waves of 76/77 GHz is −3.0 dB (approximately 50%). I know what I can do. Furthermore, it can be seen that the electromagnetic wave transmittance of the radome 1a for millimeter waves of 76/77 GHz can be reduced to -1.0 dB (approximately 80%) by setting the area variation coefficient of the island-like metal regions 31a to 1.0 or less. That is, by setting the coefficient of variation of the area of the island-like metal regions 31a, which are aggregates of the discontinuous metal films 3a, to 1.5 or less, preferably 1.0 or less, practically sufficient electromagnetic wave permeability can be achieved. It is possible to obtain a radome 1a that exhibits. Further, from the measurement results of FIG. 4, as the coefficient of variation increases, the conductivity increases and the transmittance decreases. It can be seen that the electromagnetic wave transmittance changes as the conductivity changes. Therefore, it can be said that the relationship between the variation coefficient and the millimeter wave transmittance holds regardless of the material of the discontinuous metal film 3a.
　〔レドームの色調の測定試験〕
　次に、本発明の実施例の車載レーダー装置用レドーム及び比較例の車載レーダー装置用レドームのサンプルとして、図５に示すレドーム１ｂを作成し、レドーム１ｂの色調を測定する測定試験を行った。レドーム１ｂは、電磁波透過性を有する絶縁基材２ｂの一方の面に、微細なクラック３２ｂで分割された島状金属領域３１ｂの集合体である不連続金属膜３ｂを積層するように固着されていると共に、絶縁基材２ｂの一方の面側において不連続金属膜３ｂの各々の島状金属領域３１ｂを覆うように別の絶縁基材４ｂが設けられ、別の絶縁基材４が、クラック３２ｂの箇所で絶縁基材２ｂに固着されていると共に、島状金属領域３１ｂに固着されている。 [Measurement test of color tone of radome]
Next, a radome 1b shown in FIG. 5 was prepared as a sample of the radome for the vehicle-mounted radar system of the embodiment of the present invention and the radome for the vehicle-mounted radar system of the comparative example, and a measurement test was conducted to measure the color tone of the radome 1b. In the radome 1b, a discontinuous metal film 3b, which is an aggregate of island-shaped metal regions 31b divided by fine cracks 32b, is laminated on one surface of an insulating base material 2b having electromagnetic wave permeability. In addition, another insulating base material 4b is provided so as to cover each island-shaped metal region 31b of the discontinuous metal film 3b on one surface side of the insulating base material 2b, and the another insulating base material 4 is provided with cracks 32b. It is fixed to the insulating base material 2b at the point , and is also fixed to the island-shaped metal region 31b.
　レドーム１ｂの絶縁基材２ｂは、レドーム１ａの絶縁基材２ａと同様に、透明合成樹脂のポリカーボネートで形成されており、縦７０ｍｍ、横１５０ｍｍ、厚さ３ｍｍの長方形の平板になっている。透明のポリカーボネートで形成されたレドーム１ｂの厚さ方向における可視光透過率は８９％である。また、レドーム１ｂの別の絶縁基材４ｂは、非透光性のＡＥＳ樹脂で形成されており、縦７０ｍｍ、横１５０ｍｍ、厚さ３ｍｍの長方形の平板になっている。 Like the insulating base material 2a of the radome 1a, the insulating base material 2b of the radome 1b is made of transparent synthetic resin polycarbonate, and is a rectangular flat plate measuring 70 mm long, 150 mm wide and 3 mm thick. The visible light transmittance in the thickness direction of the radome 1b made of transparent polycarbonate is 89%. Another insulating base material 4b of the radome 1b is made of a non-translucent AES resin, and is a rectangular flat plate measuring 70 mm long, 150 mm wide and 3 mm thick.
　レドーム１ｂにおける不連続金属膜３ｂの島状金属領域３１ｂはインジウムで形成されており、絶縁基材２ｂの一方の面にスパッタリングで形成されている。各サンプルのレドーム１ｂにおける不連続金属膜３ｂの膜厚は２０ｎｍ～６０ｎｍの範囲にあるものとし、又、レドーム１ｂの不連続金属膜３ｂにおける単位面積（１ｍｍ２）当たりの微細な島状金属領域３１ｂの個数は１２，５００個～２００，０００，０００個の範囲にあるものとし、不連続金属膜３ｂの島状金属領域３１ｂの面積の変動係数が０．５～１．５の範囲にあるものとし、この状態をレドーム１ｂに対する画像解析処理（使用画像解析ソフトウェア：Image J(National Institutes of Health製)）で確認した。 The island-shaped metal regions 31b of the discontinuous metal film 3b in the radome 1b are made of indium, and are formed by sputtering on one surface of the insulating substrate 2b. The film thickness of the discontinuous metal film 3b in the radome 1b of each sample is in the range of 20 nm to 60 nm. The number of 31b is in the range of 12,500 to 200,000,000, and the area variation coefficient of the island-like metal regions 31b of the discontinuous metal film 3b is in the range of 0.5 to 1.5. This state was confirmed by image analysis processing for the radome 1b (image analysis software used: Image J (manufactured by National Institutes of Health)).
　レドーム１ｂの色調の測定は、コニカミノルタ社製の分光測色計（CM-3700d）を色調測定装置２００として用いて実施した。図５の色調測定装置２００における符号２０１は測定部であり、試料に対する開口部になっている。また、図６は開口の測定部２０１から視認されるレドーム１ｂの例である。そして、サンプルのレドーム１ｂのそれぞれにおいて、島状金属領域３１ｂの平均面積を約１０，０００ｎｍ２、約２０，０００ｎｍ２、約３０，０００ｎｍ２、約４０，０００ｎｍ２、約８５，０００ｎｍ２に設定し、各サンプルのレドーム１ｂの黄色味の強弱を示すｂ*値（プラスで絶対値が大きいほど黄色味が強く、マイナスで絶対値が大きいほど青色味が強くなる）を測定した。その測定結果を図７に示す。 The color tone of the radome 1b was measured using a spectrophotometer (CM-3700d) manufactured by Konica Minolta as the color tone measuring device 200 . Reference numeral 201 in the color tone measuring apparatus 200 of FIG. 5 is a measuring section, which is an opening for the sample. Also, FIG. 6 is an example of the radome 1b viewed from the opening measuring part 201. In FIG. Then, in each of the sample radomes 1b, the average areas of the island-shaped metal regions 31b are set to about 10,000 nm 2 , about 20,000 nm 2 , about 30,000 nm 2 , about 40,000 nm 2 , and about 85,000 nm 2 . Then, the b* value indicating the degree of yellowness of the radome 1b of each sample was measured (the larger the positive absolute value, the stronger the yellowishness, and the larger the negative absolute value, the stronger the bluishness). The measurement results are shown in FIG.
　島状金属領域３１ｂの平均面積が約１０，０００ｎｍ２の場合におけるｂ*値の最大値と最小値の差は１．８７、島状金属領域３１ｂの平均面積が約２０，０００ｎｍ２の場合におけるｂ*値の最大値と最小値の差は１．３１、島状金属領域３１ｂの平均面積が約３０，０００ｎｍ２の場合におけるｂ*値の最大値と最小値の差は１．０８、島状金属領域３１ｂの平均面積が約４０，０００ｎｍ２の場合におけるｂ*値の最大値と最小値の差は１．０８、島状金属領域３１ｂの平均面積が約８５，０００ｎｍ２の場合におけるｂ*値の最大値と最小値の差は０．１３程度となり、島状金属領域３１ｂの平均面積が大きいほどｂ*値のバラツキは小さくなる。 When the average area of the island-shaped metal regions 31b is about 10,000 nm2 , the difference between the maximum and minimum b* values is 1.87 . The difference between the maximum and minimum b* values is 1.31 . The difference between the maximum and minimum b* values when the average area of the island-shaped metal regions 31b is about 40,000 nm2 is 1.08, and when the average area of the island-shaped metal regions 31b is about 85,000 nm2 , b The difference between the maximum value and the minimum value of * is about 0.13, and the larger the average area of the island-like metal regions 31b, the smaller the variation in the b* value.
　そして、ｂ*値の最大値と最小値の差が１．５以上になると、量産時に個体による不連続金属膜３ｂの色の違いが視認され易くなってしまうが、レドーム１ｂの島状金属領域３１ｂの平均面積を２０，０００ｎｍ２以上とすることにより、ｂ*値の最大値と最小値の差を１．５未満とすることができ、個体による不連続金属膜３ｂの色の違いを視認できないレベルに抑えられることが分かる。 When the difference between the maximum and minimum values of b* is 1.5 or more, the difference in color of the discontinuous metal film 3b depending on the individual is likely to be visually recognized during mass production. By setting the average area of 31b to 20,000 nm 2 or more, the difference between the maximum and minimum b* values can be less than 1.5, and the difference in color of the discontinuous metal film 3b depending on the individual can be visually recognized. It can be seen that it can be suppressed to an impossible level.
　本発明は、車載レーダー装置用レドームとして利用することができる。 The present invention can be used as a radome for an in-vehicle radar device.
１、１ａ、１ｂ…車載レーダー装置用レドーム　２、２ａ、２ｂ…絶縁基材　３、３ａ、３ｂ…不連続金属膜　３１、３１ａ、３１ｂ…島状金属領域　３２、３２ａ、３２ｂ…クラック　４、４ｂ…別の絶縁基材　１０…車載レーダー装置　１０１…電磁波発信部　１０２…受信部　１０３…評価装置　２００…色調測定装置　２０１…測定部　ＥＷ…電磁波
  Reference Signs List 1, 1a, 1b... Radome for in- vehicle radar device 2, 2a, 2b... Insulating base material 3, 3a, 3b... Discontinuous metal film 31, 31a, 31b... Island- like metal region 32, 32a, 32b... Crack 4, 4b ... Another insulating base material 10 ... In-vehicle radar device 101 ... Electromagnetic wave transmitter 102 ... Receiver 103 ... Evaluation device 200 ... Color tone measuring device 201 ... Measurement unit EW... Electromagnetic wave

Claims (3)

  1. 　絶縁基材の一方の面に相互に分離された島状金属領域の集合体である不連続金属膜が積層して固着され、車載レーダー装置の前側に設けられる車載レーダー装置用レドームであって、
    　前記島状金属領域の平均面積が１０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲にあると共に、
    　前記島状金属領域の面積の変動係数が０．５～１．５の範囲にあることを特徴とする車載レーダー装置用レドーム。     A radome for an in-vehicle radar device provided on the front side of the in-vehicle radar device, wherein a discontinuous metal film, which is an aggregate of island-shaped metal regions separated from each other, is laminated and fixed to one surface of an insulating base material,
    The average area of the island-shaped metal regions is in the range of 10,000 nm 2 to 80,000,000 nm 2 , and
    A radome for an in-vehicle radar device, wherein the coefficient of variation of the area of the island-shaped metal region is in the range of 0.5 to 1.5.
  2. 　前記島状金属領域の面積の変動係数が０．５～１．０の範囲にあることを特徴とする請求項１記載の車載レーダー装置用レドーム。 The radome for a vehicle-mounted radar device according to claim 1, characterized in that the coefficient of variation of the area of said island-shaped metal regions is in the range of 0.5 to 1.0.
  3. 　前記島状金属領域の平均面積が２０，０００ｎｍ２～８０，０００，０００ｎｍ２の範囲にあることを特徴とする請求項１又は２記載の車載レーダー装置用レドーム。
          3. The radome for vehicle-mounted radar equipment according to claim 1, wherein the average area of said island-shaped metal regions is in the range of 20,000 nm 2 to 80,000,000 nm 2 .
PCT/JP2022/032880 2021-10-20 2022-08-31 Radome for on-board radar WO2023067907A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2021172047A JP7242151B1 (en) 2021-10-20 2021-10-20 Radome for in-vehicle radar equipment
JP2021-172047 2021-10-20

Publications (1)

Publication Number Publication Date
WO2023067907A1 true WO2023067907A1 (en) 2023-04-27

Family

ID=85641219

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2022/032880 WO2023067907A1 (en) 2021-10-20 2022-08-31 Radome for on-board radar

Country Status (2)

Country Link
JP (1) JP7242151B1 (en)
WO (1) WO2023067907A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010251899A (en) * 2009-04-13 2010-11-04 Sankei Giken Kogyo Co Ltd Metal composite material of electromagnetic wave transparency and method for manufacturing the same
WO2019208504A1 (en) * 2018-04-23 2019-10-31 日東電工株式会社 Electromagnetic wave transparent metallic luster article, and metal thin film

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010251899A (en) * 2009-04-13 2010-11-04 Sankei Giken Kogyo Co Ltd Metal composite material of electromagnetic wave transparency and method for manufacturing the same
WO2019208504A1 (en) * 2018-04-23 2019-10-31 日東電工株式会社 Electromagnetic wave transparent metallic luster article, and metal thin film

Also Published As

Publication number Publication date
JP7242151B1 (en) 2023-03-20
JP2023061854A (en) 2023-05-02

Similar Documents

Publication Publication Date Title
CN106908884B (en) Radio wave-transparent layer having metallic luster
CN111758043B (en) Electromagnetic wave penetrable cover and method for manufacturing same
JP5237713B2 (en) Electromagnetic wave transmitting brightly painted resin product and manufacturing method
CN109983620B (en) Multi-piece vehicle radome with non-uniform back piece and method of making same
US12032093B2 (en) Radome for on-board radar device
US10794757B2 (en) Near-infrared sensor cover
JP3720039B2 (en) How to make a radome for distance warning radar
JP7313106B2 (en) Radome for in-vehicle radar equipment
JP4872886B2 (en) Resin molded product placed in the beam path of radio radar equipment
KR101745053B1 (en) Surface treatment of the metallic member using on transmission path of the radar and a method of manufacturing it
EP2848474A1 (en) Vehicular exterior member
JP2010188987A (en) Exterior member for vehicle, and front grille
WO2023067907A1 (en) Radome for on-board radar
CN111712397B (en) Decoration composite body
CN112020423B (en) Electromagnetic wave-transparent metallic glossy article and metallic film
CN113544529A (en) Radar cover
JP2019123819A (en) Millimeter wave transparent gloss coated film and resin product
CN112004664A (en) Electromagnetic wave transmitting metallic luster article
CN213043058U (en) Motor vehicle radome with decorative pattern
KR101918351B1 (en) Cover having metallic luster
CN112004663A (en) Electromagnetic wave-permeable metallic luster article and metallic thin film
JP2021028621A (en) On-vehicle sensor cover
CN112004666A (en) Electromagnetic wave transmitting metallic luster article
JP7494796B2 (en) Millimeter wave transmission garnish
JP2018188145A (en) Vehicular ornament

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22883219

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE