WO2020100450A1

WO2020100450A1 - Infrared transmission cover

Info

Publication number: WO2020100450A1
Application number: PCT/JP2019/038282
Authority: WO
Inventors: 竹内　康人; 英登前田; 晃司奥村; 達也大庭; 新太朗大川; 宏明安藤; 功徳吉澤
Original assignee: 豊田合成株式会社
Priority date: 2018-11-14
Filing date: 2019-09-27
Publication date: 2020-05-22
Also published as: JP2020079053A; JP7242261B2

Abstract

An infrared transmission cover (30) is applied to an infrared sensor (20) mounted on a vehicle. The infrared sensor (20) is provided with a transmitter (24) for transmitting infrared rays (IR) in the wavelength range of 900 nm to 1600 nm toward the outside of the vehicle and a receiver (25) for receiving the infrared rays (IR) impinging on and reflected by an object outside the vehicle. An infrared transmission cover (30) is provided with a cover body (32) for covering the transmitter (24) and the receiver (25). The cover body (32) includes a base material (33) and a film layer (36). The base material (33) is formed from a transparent resin material through which infrared rays (IR) can be transmitted and has grains (34) at a portion of the rear surface in the transmission direction of the infrared rays (IR). The film layer (36) covers the base material (33) from behind in the transmission direction while filling around the irregular portions of the grains (34), and reflects visible light while allowing the infrared rays (IR) to pass therethrough. The transmissivity of the cover body (32) for the infrared rays (IR) is greater than or equal to 50%.

Description

Infrared transparent cover

The present disclosure is applied to an infrared sensor mounted on a vehicle as a sensor for detecting a situation around the vehicle, and relates to an infrared transparent cover that covers an infrared transmitter and a receiver of the infrared sensor.

Infrared sensors or radio wave radar devices tend to be mounted on the vehicle to detect the situation around the vehicle. The infrared sensor transmits infrared rays to the outside of the vehicle, and receives infrared rays reflected by hitting objects outside the vehicle, including preceding vehicles and pedestrians. The radio wave radar device transmits radio waves such as millimeter waves to the outside of the vehicle and receives the radio waves reflected by an object outside the vehicle. These infrared rays and radio waves are used for recognizing the object, and for detecting the distance between the vehicle and the object, the relative speed, and the like.

If the above infrared sensors or radio wave radar devices are placed in exposed states, they will be visible from outside the vehicle. Due to this, not only the infrared sensor itself or the radio wave radar device itself, but also the appearance around the infrared sensor or the radio wave radar device in the vehicle is impaired. Therefore, an infrared transparent cover that covers the infrared transmitter and receiver of the infrared sensor and has infrared transparency is disposed in front of the infrared sensor in the infrared transmission direction. Further, a radio wave transmission cover that hides the radio wave radar device and has radio wave transparency is disposed in front of the radio wave radar device in the radio wave transmission direction.

When the infrared transparent cover or the radio wave transparent cover is attached, if the color of the infrared transparent cover or the radio wave transparent cover is different from the color of the surrounding design parts, a sense of unity with the design parts cannot be obtained, and the designability deteriorates. Therefore, various radio wave transmission covers have been studied that can enhance the design by giving a sense of unity with the design component by matching colors and the like with the design component. For example, Patent Document 1 describes a radio wave transmission cover including a base material made of a transparent resin material. A fine concavo-convex portion is provided on the rear surface of the base material in the radio wave transmission direction. According to this radio wave transmission cover, the visible light is reflected and diffused in the fine irregularities, so that a sense of unity with peripheral design components can be provided and the designability can be improved. In addition, the depth of the uneven portion is set to 1/4 to 1/10 or less of the wavelength of the radio wave, so that the radio wave transmission in the radio wave transmission cover is ensured.

Japanese Patent No. 5610344

The improvement in design mentioned above is required not only for the radio wave transmission cover but also for the infrared transmission cover. Therefore, it is possible to apply the fine uneven | corrugated part described in the said patent document 1 to an infrared transmission cover. In this case, the infrared transparent cover includes a base material made of a transparent resin material, and fine irregularities are provided on the rear surface of the base material in the infrared transmission direction.

However, when the infrared transmittance of the infrared transmissive cover provided with fine irregularities on the rear surface of the base material was measured, it was found to be lower than 50%. It is considered that this is because a large amount of infrared light is reflected by the uneven portion. Therefore, merely providing a fine concave-convex portion on the rear surface of the base material in the transmission direction can provide a sense of unity with the peripheral design component. It is difficult for infrared rays to sufficiently pass through the infrared transparent cover, and it is difficult for the infrared sensor to sufficiently exhibit the function of recognizing an object outside the vehicle and the function of detecting the distance between the vehicle and the object, the relative speed, and the like.

It should be noted that, as another measure for enhancing the designability by giving a feeling of unity with the design component, it is conceivable to provide a concave portion larger than the fine uneven portion on a part of the rear surface of the base material in the transmission direction. Since infrared rays are largely refracted when passing through the recesses, the transmittance is low. Further, as another measure, it is conceivable to form a coating layer made of a metallic material on a part of the rear surface of the base material in the transmission direction, but since infrared rays are reflected by the coating layer, the transmittance is Low. As described above, none of the above measures has a problem in that the infrared detecting function of the infrared sensor cannot be secured.

An object of the present disclosure is to provide an infrared transmissive cover that can improve the design while ensuring the detection function of the infrared sensor.

The infrared transparent cover according to the first aspect for solving the above-mentioned problems is mounted on the vehicle as a sensor for detecting a situation around the vehicle, and a transmitting section for transmitting infrared rays in a wavelength range of 900 nm to 1600 nm to the outside of the vehicle. And an infrared transmissive cover that is applied to an infrared sensor that includes a receiver that receives infrared rays reflected by an object outside the vehicle, and that is an infrared transmissive cover that includes a cover body that covers the transmitter and the receiver, wherein the cover body is A base material formed of a transparent resin material having infrared transparency and having a back surface in the infrared transmission direction as a target surface and a wrinkle formed on the target surface, and filling the uneven portion of the wrinkle. In the above state, the base material is covered from the rear side in the transmission direction, and a coating layer that reflects visible light and has infrared transparency is provided, and the infrared transmittance of the cover body is 50. % Or more.

The term "transparency" here includes not only colorless transparency but also colored transparency (colored transparency).
According to the above configuration, when the cover body is irradiated with visible light from the front in the infrared transmission direction, the visible light passes through the base material. Some of the visible light that has passed through the substrate strikes the grain and is reflected at various angles. On the rear surface of the base material and the coating layer in the transmission direction, there are a spot (shade) where the visible light does not hit and a spot (shadow) where the light is blocked by the texture. Therefore, from the front of the infrared transmission cover in the transmission direction, a portion corresponding to the grain can be seen in a shaded state. Due to this shadow, a sense of unity with the design parts around the infrared transmission cover is obtained in the vehicle, and the designability is enhanced.

Also, part of the visible light that has passed through the base material is reflected by the coating layer. The reflectance of visible light is 1% or more. The color of the visible light reflected can be seen from the front of the infrared transmission cover in the transmission direction.

Therefore, the coating layer suppresses (shields) the parts that are located behind the cover body in the transmission direction, especially the transmission and reception parts of the infrared sensor, to be seen through. The coating layer has infrared transparency.

Here, in addition to exhibiting the above-mentioned shielding effect, the coating layer is provided by coating the base material from the rear side in the transmission direction in a state where the uneven portions of the texture are filled. Compared to the case without it, it also exerts the function of increasing the infrared transmittance in the grain. This is because if there is only a grain and no coating layer, infrared rays will be reflected (refracted) at various angles due to the irregularities of the grain. However, when the uneven portion of the grain is filled with the coating layer, the unevenness disappears or becomes gentle and the reflection amount decreases.

When infrared rays are transmitted from the transmitter of the infrared sensor, the infrared rays sequentially pass through the coating layer and the base material in the cover body. At this time, part of the infrared rays passes through the grain. The infrared light transmitted through the cover main body hits an object outside the vehicle including a preceding vehicle and a pedestrian and is reflected, and then again passes through the base material and the coating layer in the cover main body in order. At this time, part of the infrared rays passes through the grain. The infrared light transmitted through the cover body is received by the receiver. The infrared sensor recognizes an object or detects the distance between the vehicle and the object, the relative speed, and the like based on the infrared rays transmitted and received.

Since the infrared transmittance of the cover body is 50% or more, the cover body does not easily interfere with the infrared transmission. Therefore, the infrared sensor is likely to exhibit the function of recognizing the object, the function of detecting the distance between the vehicle and the object, the relative speed, and the like. The infrared rays are reflected by the grain.

In the infrared transparent cover, it is preferable that the grain has a depth of 5 μm to 50 μm.
As the depth of the texture becomes deeper, the uneven portion of the texture becomes more visible, so that the designability is improved, but infrared rays are more likely to be reflected and the transmittance is reduced. On the contrary, as the depth of the texture becomes shallower, the infrared rays are less likely to be reflected and the transmittance is higher, but the uneven portion of the texture becomes less visible and the design is deteriorated.

In this respect, when the wrinkles are formed to a depth of 5 μm to 50 μm as in the above configuration, it is possible to improve both the design and the transmittance.
An infrared transmitting cover according to a second aspect for solving the above-mentioned problems is mounted on the vehicle as a sensor for detecting a situation around the vehicle, and a transmitting section for transmitting infrared rays in a wavelength range of 900 nm to 1600 nm to the outside of the vehicle. And an infrared transmissive cover that is applied to an infrared sensor that includes a receiver that receives infrared rays reflected by an object outside the vehicle, and that is an infrared transmissive cover that includes a cover body that covers the transmitter and the receiver, wherein the cover body is A base material formed of a transparent resin material having infrared transparency, and a bright layer formed on the target surface with a part of the rear surface of the base material in the infrared transmission direction as a target surface; While covering the base material and the glitter layer from the rear side in the transmission direction, the coating layer that reflects visible light and has infrared transparency, the glitter layer, the core, and the core It is formed of a coating film formed of materials having different refractive indexes, and a filler including a shell that covers the core is dispersed therein, and the infrared transmittance of the cover main body is 50% or more.

The term "transparency" here includes not only colorless transparency but also colored transparency (colored transparency).
According to the above configuration, when the cover body is irradiated with visible light from the front in the infrared transmission direction, the visible light passes through the base material. After passing through the base material, part of the visible light that has entered the glitter layer strikes the surface of the shell and is reflected. Another part of the visible light is refracted at the surface of the shell, enters the shell, is reflected at the boundary between the shell and the core, and goes out of the shell again. These two types of visible light interfere with each other when their phases are aligned, and only the visible light of that color is intensified. Which color of visible light is enhanced depends on the thickness of the shell. Therefore, by adjusting the thickness of the shell, it is possible to enhance visible light of a specific color having a wavelength corresponding to the thickness. From the front of the infrared transmission cover in the transmission direction, the reflected visible light looks like a metal with a specific color. That is, a color with metallic luster can be seen from the front of the infrared transmission cover in the transmission direction.

Further, the color of the visible light reflected and enhanced by the shell and the core is matched with the color of the design component around the infrared transmission cover in the vehicle, so that a sense of unity with the design component is obtained and the design is improved. ..

When the design component has a metallic luster, the metallic luster portion of the glitter layer further enhances the feeling of unity with the design component and further improves the designability.
Further, a part of visible light transmitted through the base material is reflected by the coating layer. The reflectance of visible light is 1% or more. The color of the visible light reflected can be seen from the front of the infrared transmission cover in the transmission direction.

Therefore, it is possible to suppress (shield) the parts that are located behind the cover main body portion in the transmission direction, particularly the transmission portion and the reception portion of the infrared sensor, to be seen through.
When infrared rays are transmitted from the transmitter of the infrared sensor, the infrared rays penetrate the coating layer and the base material in the cover body. At this time, part of the infrared rays passes through the bright layer and another part passes through the coating layer. The infrared light that has passed through the cover main body hits an object outside the vehicle including a preceding vehicle, a pedestrian, etc., and is reflected, and then again passes through the base material and the coating layer in the cover main body. At this time, part of the infrared rays passes through the bright layer and another part passes through the coating layer. The infrared light transmitted through the cover body is received by the receiver. The infrared sensor recognizes an object or detects the distance between the vehicle and the object, the relative speed, and the like based on the infrared rays transmitted and received.

Since the infrared transmittance of the cover body is 50% or more, it is unlikely that the cover body will interfere with infrared transmission. Therefore, the infrared sensor is likely to exhibit the function of recognizing the object, the function of detecting the distance between the vehicle and the object, the relative speed, and the like.

In the infrared transparent cover, the filler may be one in which the core is made of aluminum oxide or titanium oxide, and the shell is made of pearl mica having tin oxide or zirconium oxide. Further, the filler may be one in which the core is made of silicon dioxide and the shell is made of a glass filler made of titanium oxide.

The infrared transmission cover is an infrared transmission cover having the radiator grill as a peripheral design component by being arranged in a window portion formed in the radiator grill of the vehicle, and the radiator grill has a lattice portion. Therefore, it is preferable that the target surface is set at a position adjacent to the lattice portion.

According to the above configuration, from the front of the infrared ray transmitting cover in the infrared ray transmitting direction, the shaded portion due to grain or the metallic luster portion due to the glitter layer appear to be continuous with the lattice portion. Therefore, as compared with the case where the shaded portion or the metallic luster portion is distant from the lattice portion, the feeling of unity with the design component of the infrared transmission cover is further enhanced, and the designability is further improved.

In the infrared transparent cover, the lattice portion has a horizontal lattice portion extending in the vehicle width direction, the horizontal lattice portion is divided into a pair of horizontal lattice constituent portions by the formation of the window portion, It is preferable that the target surface is set on the same line as both the horizontal lattice constituent parts.

According to the above configuration, the shaded portion due to the grain or the metallic luster portion due to the glitter layer is located between both horizontal lattice constituent portions of the horizontal lattice portion. From the front side of the infrared transmission cover in the transmission direction, it appears that both horizontal lattice constituent parts are connected in a straight line via the shaded portion or the metallic gloss portion. Therefore, the sense of unity between the infrared transparent cover and the surrounding design parts is further enhanced, and the designability is further improved.

With the infrared transparent cover, it is possible to improve the design while ensuring the detection function of the infrared sensor.

It is a figure showing a 1st embodiment, and is a sectional side view showing an infrared sensor and an infrared transparent cover which is provided separately from the infrared sensor and which is arranged in front of the infrared sensor in an infrared transmission direction. FIG. 2 is an enlarged side sectional view of a grain and its peripheral portion in the infrared transmission cover of FIG. 1. FIG. 3A is a front view of a vehicle to which the infrared transmissive cover of the first embodiment is applied, and FIG. 3B is a partial front view showing a part of FIG. It is a figure explaining the effect of 1st Embodiment, and is a graph which shows the result of having measured the relationship between the depth of a wrinkle and the transmittance | permeability of infrared rays about Example 1 and the comparative example 1. It is a figure explaining the effect of 1st Embodiment, and is a graph which shows the result of having measured the transmittance | permeability of the infrared ray in the infrared rays transmission cover of the comparative example 2 in which the wrinkle and the coating layer are not formed. It is a figure explaining the effect of 1st Embodiment, and is a graph which shows the result of having measured the transmittance | permeability of the infrared rays in the infrared transmission cover of Example 2 in which the wrinkle and the coating film layer were formed for every wavelength. The partial sectional side view of the cover body part in the infrared penetration cover of a 2nd embodiment. (A) is sectional drawing which shows schematic structure of the filler in 2nd Embodiment, (b) is a partial expanded sectional view of Fig.8 (a). The sectional side view of the infrared sensor of the modification in which the cover also served as the infrared transparent cover.

(First embodiment)
Hereinafter, a first embodiment in which the infrared transparent cover is embodied will be described with reference to FIGS. 1 to 6.

Note that, in the following description, the forward direction of the vehicle is the front and the reverse direction is the rear. Further, the up-down direction means the up-down direction of the vehicle, the left-right direction is the vehicle width direction, and coincides with the left-right direction when the vehicle is moving forward. In addition, in FIGS. 1 and 2, in order to make each part of the infrared transmission cover 30 recognizable, the scale is appropriately changed to show each part. This point is the same as in FIG. 7 and FIGS. 8A and 8B showing the second embodiment, and also in FIG. 9 showing a modified example.

As shown in FIG. 3 (a), a radiator grill 14 is arranged at the front of the vehicle 10, between the hood 11 and the front bumper 12, and between the pair of headlamps 13.

The radiator grille 14 has a function of guiding outside air such as traveling wind to a radiator (not shown) to cool the radiator. The radiator grille 14 includes a horizontally long rectangular frame portion 15 and a lattice portion 16 provided in a region surrounded by the frame portion 15. The lattice portion 16 has a plurality of horizontal lattice portions 17. These horizontal lattice portions 17 extend in the vehicle width direction and are bridged between both side wall portions of the frame portion 15. The radiator grill 14 having such a structure corresponds to a peripheral design part for the infrared ray transmitting covers 30, 40, 50 described later.

Further, as shown in FIG. 3B, a rectangular frame-shaped window portion 19 is formed in the center portion of the radiator grill 14 in the vehicle width direction. Due to the formation of the window portions 19, some of the horizontal lattice portions 17 are divided at the central portion in the vehicle width direction. Here, the portions of the horizontal lattice portion 17 on both sides of the window portion 19 in the vehicle width direction are referred to as horizontal lattice forming portions 18. As shown in FIG. 3B, the two horizontal lattice forming portions 18 corresponding to one horizontal lattice portion 17 are separated from each other in the vehicle width direction with the window portion 19 interposed therebetween so as to form a pair.

In the space between the window 19 and the radiator, an infrared sensor 20 shown in FIG. 1 is mounted as a sensor for detecting the situation around the vehicle 10.
The infrared sensor 20 transmits the infrared IR toward the front of the vehicle 10 and receives the infrared IR reflected by hitting an object outside the vehicle such as a preceding vehicle or a pedestrian. Infrared IR is a type of electromagnetic wave, and has a wavelength longer than that of visible light and shorter than that of radio waves. The infrared sensor 20 recognizes the object outside the vehicle based on the transmitted infrared IR and the received infrared IR, and also detects the distance between the vehicle 10 and the object, the relative speed, and the like.

As described above, since the infrared sensor 20 transmits the infrared IR toward the front of the vehicle 10, the infrared sensor 20 transmits the infrared IR from the rear to the front of the vehicle 10. The front in the transmission direction of the infrared IR substantially matches the front of the vehicle 10, and the rear in the same transmission direction substantially matches the rear of the vehicle 10. Therefore, in the following description, the front in the infrared IR transmission direction is simply referred to as “front”, “front”, and the rear in the same transmission direction is simply referred to as “rear”, “rear”, and the like.

As shown in FIG. 1, the latter half of the outer shell of the infrared sensor 20 is composed of the case 21, and the first half is composed of the cover 26. The infrared sensor 20 is fixed to the vehicle body or the like.

The case 21 includes a cylindrical peripheral wall portion 22 and a bottom wall portion 23 formed at the rear end of the peripheral wall portion 22. That is, the case 21 has a bottomed cylindrical shape with an open front surface. The entire case 21 is made of a resin material such as polybutylene terephthalate resin (PBT). On the front side of the bottom wall portion 23, a transmitting portion 24 for transmitting the infrared IR and a receiving portion 25 for receiving the infrared IR are arranged.

The cover 26 is made of a resin material containing a visible light cut pigment. Examples of applicable resin materials include polycarbonate resin (PC), polymethylmethacrylate resin (PMMA), cycloolefin polymer (COP), resin glass, and the like. The cover 26 is arranged on the front side of the case 21 and covers the transmitter 24 and the receiver 25 from the front.

As shown in FIGS. 1 and 3A and 3B, an infrared transmission cover 30 provided separately from the infrared sensor 20 is arranged in the window portion 19. The infrared transparent cover 30 includes a plate-shaped cover body portion 32 and a mounting portion 31 that projects rearward from the rear surface of the cover body portion 32. The cover body 32 is located in front of the cover 26, and indirectly covers the transmitter 24 and the receiver 25 from the front via the cover 26. The infrared transparent cover 30 is fixed to the vehicle body or the like at the mounting portion 31.

The infrared transparent cover 30 has a function as a cover of the infrared sensor 20 and also has a function as a garnish for decorating the front portion of the vehicle 10.
As shown in FIG. 1, the cover body 32 includes a base material 33, a coating layer 36, and a hard coat layer 37.

The base material 33 is formed of a transparent resin material having infrared IR transparency, for example, PC, PMMA, COP, or the like. The transparency here includes colorless transparency as well as colored transparency (colored transparency).

As shown in FIGS. 2 and 3B, the target surface 29 is set on a part of the rear surface of the base material 33. The target surface 29 is set in a region of the horizontal lattice portion 17 divided by the formation of the window portion 19, that is, a strip-shaped region extending in the vehicle width direction. The target surface 29 is located at the same or substantially the same height as each pair of the horizontal lattice forming portions 18, and has the same or substantially the same vertical width as the vertical width of the horizontal lattice forming portions 18. Both ends of the target surface 29 in the vehicle width direction are adjacent to the pair of horizontal lattice constituent parts 18. In other words, the target surface 29 is set on the same line as the pair of horizontal lattice constituent parts 18.

As shown in FIGS. 1 and 2, the target surface 29 is provided with a wrinkle 34 having a fine uneven pattern (wrinkle pattern). The wrinkles 34 may be wrinkle patterns called convex wrinkles formed by a regular pattern, or wrinkle patterns called pearskin wrinkles formed by an irregular pattern. In the first embodiment, a satin texture is formed as the texture 34. The concavo-convex portion 35 of the embossment 34 has a depth of 5 μm to 50 μm.

The coating layer 36 is formed by applying an infrared transparent ink (IR ink), which is known as a material having a high infrared IR transmittance and a low visible light transmittance, to the rear surface of the base material 33 including the embosses 34. Is formed by. The coating film layer 36 covers the base material 33 from the rear side in a state where the concave and convex portions 35 of the grain 34 are filled. As the IR ink, one having a refractive index closer to that of the base material 33 is desirable. In the first embodiment, the coating layer 36 is made of a coating material containing a black pigment.

The hard coat layer 37 is formed on the front surface of the base material 33 and has infrared IR transparency and hardness higher than that of the base material 33. The hard coat layer 37 is formed by applying a known surface treatment agent to the front surface of the base material 33. Examples of the surface treatment agent include acrylate-based, oxetane-based, and silicone-based organic hard coating agents, inorganic hard coating agents, organic-inorganic hybrid hard coating agents, and the like.

The required value of the infrared IR transmittance of the cover body 32 is 50%, and the cover body 32 of the first embodiment has a transmittance of 50% or more.
FIG. 4 shows the result of measurement of the relationship between the depth of the uneven portion in the texture and the infrared transmittance of the cover body. In FIG. 4, the solid line indicates the measurement result of the infrared transmission cover of Example 1 in which the rear surface of the textured substrate was covered with the coating layer. In FIG. 4, the alternate long and two short dashes line shows the measurement result of the infrared transmission cover of Comparative Example 1 in which the coating layer is not formed and the wrinkles are exposed.

In either case, the transmittance decreases as the depth of the emboss becomes deeper.
In Comparative Example 1, it can be seen that the transmittance is below the required value of 50% regardless of the depth of the texture. Further, in Example 1, it can be seen that the transmittance is 50% or more in the region where the depth of the wrinkles is 5 μm to 50 μm. In Example 1, the transmittance is less than 50% in the region where the depth of the wrinkles is larger than 50 μm.

Further, FIG. 5 shows the results of measuring the infrared transmittance for each wavelength in the infrared transparent cover of Comparative Example 2 in which the texture and the coating layer are not formed. It can be seen from FIG. 5 that the transmittance is 50% or more in the wavelength range of 900 nm to 1600 nm.

Further, FIG. 6 shows the results of measuring the infrared transmittance for each wavelength in the infrared transparent cover of Example 2 in which the texture and the coating layer are formed. It can be seen from FIG. 6 that the transmittance is 50% or more in the wavelength range of 900 nm to 1600 nm.

Next, the operation and effect of the infrared transmission cover 30 of the first embodiment will be described.
As shown in FIGS. 2 and 3B, when visible light is applied to the cover body 32 from the front of the vehicle 10, the visible light is transmitted through the hard coat layer 37 and the base material 33 in order. A part of the visible light transmitted through the base material 33 strikes the embossed surface 34 and is reflected at various angles. On the rear surface of the base material 33 and the coating layer 36, there are a portion (shade) where the visible light does not hit in the grain 34 and a portion where the light is blocked by the grain 34 and becomes dark (shadow). Therefore, from the front of the vehicle 10, a portion corresponding to the grain 34 can be seen as a shaded shaded portion 38. The shaded portion 38 provides a sense of unity with the radiator grille 14, which is a design component around the infrared transmission cover 30 in the vehicle 10, and enhances the design.

Here, as the depth of the grain 34 becomes deeper, the uneven portion 35 becomes more visible, so that the designability is improved, but the infrared IR is easily reflected and the transmittance is reduced. On the contrary, as the depth of the grain 34 becomes shallower, the infrared IR is less likely to be reflected and the transmittance is higher, but the uneven portion 35 is less visible and the designability is deteriorated. In this respect, in the first embodiment, since the embosses 34 are formed to have a depth of 5 μm to 50 μm, both improvement in design and improvement in transmittance are achieved.

Also, from the front of the vehicle 10, the shaded portion 38 due to the grain 34 appears to be continuous with the lattice portion 16. Therefore, compared with the case where the shaded portion 38 is away from the lattice portion 16, the infrared transmission cover 30 has a greater sense of unity with the radiator grille 14, and the designability is further improved.

In particular, in the first embodiment, the shaded portion 38 is located between each pair of horizontal lattice constituent parts 18. From the front of the vehicle 10, it appears that the pair of horizontal lattice constituent parts 18 are connected in a straight line with the shaded part 38 in between. Therefore, the infrared transmission cover 30 and the radiator grille 14 have a greater sense of unity, and the design is further improved.

In addition, a part of the visible light transmitted through the base material 33 is reflected by the coating layer 36. The reflectance of visible light is 1% or more. From the front of the vehicle 10, the color of the visible light reflected can be seen.
The coating film layer 36 formed of the coating material containing the black pigment exhibits a function of hiding (shielding) a member arranged behind the infrared transmission cover 30, particularly the infrared sensor 20. Therefore, when the infrared transmissive cover 30 is viewed from the front of the vehicle 10, the infrared sensor 20 located behind it is difficult to see. Therefore, the design is improved as compared with the case where the infrared sensor 20 can be seen through the infrared transparent cover 30.

In addition to the above-described shielding effect, the coating layer 36 is not provided by coating the base material 33 from the rear side in a state in which the uneven portions 35 of the embosses 34 are filled. In comparison with the above, it also exhibits the function of increasing the infrared IR transmissivity in the grain 34. This is because if the wrinkles 34 are only present and the coating layer 36 is not present, the infrared rays IR will be reflected or refracted at various angles due to the unevenness of the wrinkles 34. However, when the uneven portion 35 of the grain 34 is filled with the coating layer 36, the unevenness disappears or becomes gentle, and the reflection amount and the refraction angle decrease.

As shown in FIG. 1, when the infrared ray IR is transmitted from the transmitting section 24 of the infrared sensor 20, the infrared ray IR is sequentially transmitted through the coating layer 36, the base material 33 and the hard coat layer 37 in the cover body 32. .. At this time, since the depth of the uneven portion 35 of the wrinkle 34 is as shallow as 5 μm to 50 μm, part of the infrared IR is transmitted through the wrinkle 34 and part of it is reflected by the wrinkle 34. Further, the infrared ray IR transmitted through the cover body 32 hits an object outside the vehicle including a preceding vehicle, a pedestrian, etc., and is reflected, and then, again, the hard coat layer 37, the base material 33 and the coating layer 36 in the cover body 32. Through in order. At this time, a part of the infrared ray IR passes through the grain 34 as described above. The infrared IR transmitted through the cover body 32 is received by the receiver 25. The infrared sensor 20 recognizes an object and detects a distance between the vehicle 10 and the object, a relative speed, and the like based on the infrared IR transmitted and received.

Since the infrared transmittance of the cover body 32 is 50% or more, which is the required value, the cover body 32 does not easily hinder the transmission of infrared IR. The amount of the infrared IR that is attenuated by the cover body 32 can be kept within an allowable range. Therefore, the infrared sensor 20 easily exhibits the function of recognizing the object and the function of detecting the distance between the vehicle 10 and the object, the relative speed, and the like.

Further, in the infrared transparent cover 30, the hard coat layer 37 formed on the front surface of the base material 33 enhances the impact resistance of the infrared transparent cover 30. Therefore, the hard coat layer 37 can prevent the front surface of the infrared transparent cover 30 from being damaged by flying stones or the like. Further, the hard coat layer 37 enhances the weather resistance of the infrared transparent cover 30. Therefore, the hard coat layer 37 can prevent the infrared transparent cover 30 from being deteriorated or deteriorated due to sunlight, wind and rain, temperature change, or the like.

(Second embodiment)
Next, a second embodiment of the infrared transparent cover will be described with reference to FIGS. 7 and 8A and 8B.

In the infrared transmissive cover 40 of the second embodiment, a glitter layer 41 for producing a metallic luster (glossy appearance) is formed on the base material 33 at a position corresponding to the grain 34 instead of the grain 34. This is different from the infrared transparent cover 30 of the first embodiment in that it is present.

In order to obtain a bright appearance, it is necessary to reflect and scatter a large amount of visible light, and in that respect, it is suitable to include a filler of a metal such as aluminum in the bright layer 41. However, when the glitter layer 41 contains a metal, not only visible light but also infrared IR is reflected. That is, when the glitter layer 41 contains a metal, the infrared rays IR do not pass through the glitter layer 41. Therefore, in the second embodiment, the glitter layer 41 is formed of a coating film in which the filler 42 is dispersed in order to provide a glitter appearance without using a metal material. The filler 42 has a property of transmitting infrared IR, which reflects part of visible light, transmits part of infrared IR, and reflects part thereof.

Each filler 42 is composed of a core 43 and a shell (coating) 44 that covers the entire core 43. The shell 44 has a refractive index different from that of the core 43. Both the core 43 and the shell 44 are formed of a material having infrared IR transparency. In the second embodiment, each of the fillers 42 is composed of a core 43 made of a low refractive index material and a shell 44 made of a high refractive index material having a higher refractive index than the core 43. There is.

As each filler 42, for example, pearl mica in which the core 43 is formed of aluminum oxide or titanium oxide and the shell 44 is formed of metal oxide such as tin oxide or zirconium oxide can be used. Further, as each filler 42, a glass filler in which the core 43 is formed of silica (silicon dioxide) and the shell 44 is formed of a metal oxide such as titanium oxide can be used.

As the material forming the core 43 and the shell 44, it is desirable to select a material having a large difference in refractive index. This is because more visible light is reflected as the difference in refractive index increases.

The infrared IR is reflected by the filler 42 as the content of the filler 42 in the glitter layer 41 increases (the concentration increases), and the transmittance of the infrared IR decreases. From the viewpoint of making the infrared IR transmittance 50% or more, it is desirable that the concentration of the filler 42 be kept to about 2 weight percent (wt%).

When the concentration of the filler 42 in the glitter layer 41 is constant, the infrared IR transmittance varies depending on the type of the filler 42. When a glass filler is used as the filler 42, the transmittance of infrared IR tends to be higher than that when pearl mica is used.

The coating layer 36 is formed by applying the infrared transmitting ink (IR ink) similar to that of the first embodiment to the rear surface of the base material 33 and the rear surface of the glitter layer 41. In the second embodiment, the coating layer 36 is formed of a coating material containing a black pigment. The coating layer 36 covers the base 33 and the glitter layer 41 from the rear side.

The hard coat layer 37 is formed on the front surface of the substrate 33, and the infrared IR transmittance of the cover body 32 is 50% or more, which is the same as in the first embodiment.
Next, the operation and effect of the second embodiment configured as described above will be described.

When the cover body 32 is irradiated with visible light from the front of the vehicle 10, the visible light sequentially passes through the hard coat layer 37 and the base material 33. A part of the visible light transmitted through the base material 33 enters the glitter layer 41. In the bright layer 41, so-called thin film interference occurs. That is, part of the visible light that has entered the glitter layer 41 strikes the surface of the shell 44 and is reflected, as indicated by the arrow in FIG.

Further, another part of the visible light incident on the glitter layer 41 is refracted at the surface of the shell 44 and then enters the shell 44, is reflected at the boundary between the shell 44 and the core 43, and is again reflected by the shell 44. Go out. These two types of visible light interfere with each other when their phases are aligned. This interference enhances only visible light of a particular color. Which color of visible light is enhanced depends on the thickness of the shell 44. Therefore, by adjusting the thickness of the shell 44, it is possible to enhance visible light of a specific color having a wavelength corresponding to the thickness. From the front of the vehicle 10, visible light having a color enhanced by the glitter layer 41 as described above and having a shine like metal can be seen. That is, a color with metallic luster can be seen from the front of the vehicle 10.

Furthermore, the color of the visible light reflected and enhanced by the shell 44 and the core 43 of the glitter layer 41 is matched with the color of the radiator grille 14, so that a sense of unity with the radiator grille 14 can be obtained, and the design is improved. Be done.

Further, as shown in FIGS. 3B and 7, from the front of the vehicle 10, the metallic luster portion 45 of the glitter layer 41 seems to be continuous with the lattice portion 16. Therefore, compared with the case where the metallic luster portion 45 is separated from the lattice portion 16, the feeling of unity with the radiator grille 14 is further enhanced, and the designability is further improved.

In particular, in the second embodiment, the metallic luster portion 45 is located between each pair of the horizontal lattice forming portions 18. From the front of the vehicle 10, it appears that the pair of horizontal lattice forming portions 18 are connected in a straight line with the metallic luster portion 45 interposed therebetween. As a result, the infrared transmission cover 40 and the radiator grille 14 have a greater sense of unity, and the designability is further improved.

Further, when the radiator grille 14 has a metallic luster, the metallic luster portion 45 of the glitter layer 41 further enhances the sense of unity with the radiator grille 14 and further improves the design.

The coating layer 36 and the hard coat layer 37 have the same actions and effects as those of the first embodiment.
By the way, when the infrared ray IR is transmitted from the transmitting section 24 of the infrared sensor 20, the infrared ray IR passes through the coating layer 36, the base material 33 and the hard coat layer 37 in the cover main body section 32 in order as shown in FIG. To Penetrate. At this time, a part of the infrared IR is transmitted through the bright layer 41 and another part is transmitted through the coating layer 36. The infrared light IR transmitted through the cover body 32 is reflected by hitting an object outside the vehicle including a preceding vehicle and a pedestrian, and then again transmitted through the hard coat layer 37, the base material 33 and the coating layer 36 in the cover body 32 in order. To do. At this time, a part of the infrared IR is transmitted through the bright layer 41 and another part is transmitted through the coating layer 36. The infrared ray IR transmitted through the cover body 32 is received by the receiver 25. The infrared sensor 20 recognizes an object or detects a distance between the vehicle 10 and the object, a relative speed, and the like based on the infrared IR transmitted and received.

Since the transmittance of infrared IR in the cover body 32 is 50% or more, as in the first embodiment, the cover body 32 is unlikely to interfere with the transmission of infrared IR. Therefore, the infrared sensor 20 is likely to exhibit the function of recognizing the object, the function of detecting the distance between the vehicle 10 and the object, the relative speed, and the like, as in the first embodiment.

In addition, each of the above-described embodiments may be implemented as a modified example in which the following modifications are made.
In the first embodiment, the grain 34 may be changed to a grain different from the satin grain, for example, a line grain.

In the first and second embodiments described above, the coating layer 36 having infrared IR transmission is made of a coating material containing a black pigment or pearl mica, but the coating layer 36 is white. Alternatively, a coating material containing a chromatic pigment may be used. Further, the coating layer 36 may be formed by using a dye-based paint.

As the filler 42, contrary to the second embodiment, a filler 43 including a core 43 made of a high refractive index material and a shell 44 made of a low refractive index material having a lower refractive index than the core 43 is used. It may be used.

In the first and second embodiments, the infrared

transparent covers

30 and 40 are provided separately from the infrared sensor 20, but the infrared transparent cover constitutes a part of the infrared sensor 20. Good.

More specifically, as shown in FIG. 9, the cover forming the first half of the outer shell of the infrared sensor 20 may be formed by the infrared transparent cover 50. That is, the cover 26 in FIG. 1 may be changed to the infrared transparent cover 50. The infrared transparent cover 50 shown in FIG. 9 includes a cylindrical peripheral wall portion 51 and a plate-shaped cover main body portion 52 formed at the front end of the peripheral wall portion 51. The peripheral wall portion 51 is adjacent to the front side of the peripheral wall portion 22 of the case 21 in the infrared sensor 20. The peripheral portion of the cover main body 52 is expanded outward from the peripheral wall 51, but may not be expanded. Most of the cover body 52 is located in front of the bottom wall 23 of the infrared sensor 20, and covers the transmitter 24 and the receiver 25 from the front.

In this modification as well, the infrared transparent cover 50 has a function as a cover of the infrared sensor 20 and also has a function as a garnish for decorating the front portion of the vehicle 10.
The layer structure of the cover body 52 is the same as the layer structure of the cover body 32 in the first or second embodiment. Therefore, also in this modification, the same operation and effect as those of the first or second embodiment can be obtained.

The infrared

transparent covers

30, 40, 50 may be arranged in the window portion 19 formed in the lattice portion 16 having a shape different from those of the above-described embodiments.
The infrared

transparent covers

30, 40, 50 may be arranged in the window portion 19 having a shape different from that of each of the above embodiments. In this case, the shape of the cover

main body portions

32 and 52 is changed to the shape corresponding to the shape of the lattice portion 16.

The infrared

transparent covers

30, 40, 50 may be arranged in the front portion of the vehicle 10 in the window portion 19 formed in a design component different from the radiator grille 14.
The infrared

transparent covers

30, 40, 50 are also applicable to the case where the infrared sensor 20 is mounted at a position different from the front part of the vehicle 10, for example, at the rear part. In this case, the infrared sensor 20 transmits the infrared IR toward the rear of the vehicle 10. The infrared

transparent covers

30, 40, 50 are arranged in the front in the transmission direction, that is, behind the vehicle 10 with respect to each infrared sensor 20.

The infrared

transparent covers

30, 40, 50 are also applicable when the infrared sensor 20 is mounted on both sides of the front or rear of the vehicle 10, that is, the diagonal front side or the diagonal rear side.

DESCRIPTION OF SYMBOLS 10 ... Vehicle, 14 ... Radiator grille (design part), 16 ... Lattice part, 17 ... Horizontal lattice part, 18 ... Horizontal lattice forming part, 19 ... Window part, 20 ... Infrared sensor, 24 ... Transmitting part, 25 ... Receiving part , 29 ... Target surface, 30, 40, 50 ... Infrared transmitting cover, 32, 52 ... Cover body part, 33 ... Base material, 34 ... Texture, 35 ... Uneven portion, 36 ... Coating layer, 41 ... Bright layer, 42 ... Filler, 43 ... Core, 44 ... Shell, IR ... Infrared.

Claims

A transmitter mounted on the vehicle as a sensor for detecting the condition around the vehicle and transmitting infrared rays in the wavelength range of 900 nm to 1600 nm to the outside of the vehicle, and a receiver receiving infrared rays reflected by an object outside the vehicle. Which is applied to an infrared sensor comprising: an infrared transparent cover having a cover body that covers the transmitter and the receiver,
The cover body is
Formed of a transparent resin material having infrared transparency, and a part of the rear surface in the infrared transmission direction as the target surface, a base material having a wrinkle formed on the target surface,
In a state where the uneven portion of the grain is filled, while covering the base material from the rear side in the transmission direction, the visible light is reflected, and a coating layer having infrared transparency is provided,
An infrared transparent cover having an infrared transmittance of 50% or more in the cover body.
The infrared transparent cover according to claim 1, wherein the grain has a depth of 5 μm to 50 μm.
A transmitter mounted on the vehicle as a sensor for detecting the condition around the vehicle and transmitting infrared rays in the wavelength range of 900 nm to 1600 nm to the outside of the vehicle, and a receiver receiving infrared rays reflected by an object outside the vehicle. Which is applied to an infrared sensor comprising: an infrared transparent cover having a cover body that covers the transmitter and the receiver,
The cover body is
A base material formed of a transparent resin material having infrared transparency,
As a target surface a part of the rear surface of the substrate in the infrared transmission direction, and a glitter layer formed on the target surface,
While coating the base material and the glitter layer from the rear side in the transmission direction, the visible light is reflected, and a coating film layer having infrared transparency is provided,
The glitter layer is formed of a coating film in which a filler composed of a core and a shell having a refractive index different from that of the core and covering the core is dispersed,
An infrared transparent cover having an infrared transmittance of 50% or more in the cover body.
The infrared transparent cover according to claim 3, wherein the filler has a core made of aluminum oxide or titanium oxide and a shell made of pearl mica formed of tin oxide or zirconium oxide.
The infrared transparent cover according to claim 3, wherein the filler is composed of a glass filler in which the core is made of silicon dioxide and the shell is made of titanium oxide.
The infrared transmissive cover is an infrared transmissive cover in which the radiator grill is arranged in a window portion formed in the radiator grill of the vehicle, and the radiator grill is used as a peripheral design component.
The infrared transparent cover according to any one of claims 1 to 5, wherein the radiator grill has a lattice portion, and the target surface is set at a position adjacent to the lattice portion.
The lattice portion has a horizontal lattice portion extending in the vehicle width direction,
The horizontal lattice portion is divided into a pair of horizontal lattice constituent portions by forming the window portion,
The infrared transparent cover according to claim 6, wherein the target surface is set on the same line as both of the horizontal lattice constituent parts.