Light-transmissive member

Abstract

The present invention improves scratch resistance and peeling resistance while appropriately transmitting light. A light-transmissive member according to the present invention comprises: a base material that transmits far infrared rays; and a functional layer formed on at least one surface of the base material. The functional layer includes an outermost layer and a base layer formed between the outermost layer and the base material. The base layer contains C as a main component. The Ge content in the base layer is 0.1-30 atom%. The outermost layer contains C as a main component. The Ge content in the outermost layer is 15 atom% or less. The Ge content of the base layer is greater than the Ge content of the outermost layer.

Description

Transparent material

[0001] The present invention relates to a transparent member.

[0002] In order to transmit light appropriately, a layer containing germanium (Ge) and carbon (C) may be provided on a substrate. For example, Non-Patent Document 1 describes a method for depositing Ge by a chemical vapor deposition (CVD) method on a zinc sulfide (ZnS) substrate that transmits far infrared rays. １－ｘ C ｘ The document describes a transparent member having a layer formed thereon.

[0003] F. Sousani, A. Eshaghi, R. Mozafarinia, et al. Antireflection properties of germanium-carbon coating on zinc supplied substrate. Opt Quant Electron 49, 324 (2017).

[0004] Ge as shown in Non-Patent Document 1 １－ｘ C ｘ The layer has high adhesion to the substrate and high peeling resistance, but Ge １－ｘ C ｘ When this layer is used as the outermost layer, there is a possibility that sufficient scratch resistance may not be obtained, and therefore there is a demand for improving scratch resistance and peel resistance while still allowing appropriate light transmission.

[0005] An object of the present invention is to provide a transparent member that can appropriately transmit light while improving scratch resistance and peel resistance.

[0006] The transparent member according to the present disclosure comprises a substrate that transmits far-infrared rays and a functional layer formed on at least one surface of the substrate, the functional layer comprising an outermost layer and a base layer formed between the outermost layer and the substrate, the base layer containing C as a main component, the Ge content of the base layer being 0.1 atomic % or more and 30 atomic % or less, the outermost layer containing C as a main component, the Ge content of the outermost layer being 15 atomic % or less, and the Ge content of the base layer being greater than the Ge content of the outermost layer.

[0007] According to the present invention, it is possible to improve scratch resistance and peel resistance while appropriately transmitting light.

[0008] FIG. 1 is a schematic diagram showing a state in which a vehicle glass according to this embodiment is mounted on a vehicle. FIG. 2 is a schematic plan view of the vehicle glass according to this embodiment. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 2. FIG. 5 is a schematic cross-sectional view of a transparent member according to this embodiment. FIG. 6 is a schematic cross-sectional view of a transparent member according to another example of this embodiment. FIG. 7 is a schematic diagram of a manufacturing apparatus for a transparent member according to this embodiment. FIG. 8 is a plan view showing a target used in the manufacturing apparatus according to FIG. 7. FIG. 9 is a schematic diagram of a manufacturing apparatus for a transparent member according to another example of this embodiment.

[0009] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments, and when there are multiple embodiments, the present invention also includes configurations that are made by combining the respective embodiments. Furthermore, numerical values ​​include the range of rounding.

[0010] (Vehicle) Fig. 1 is a schematic diagram showing a state in which a vehicle glass according to this embodiment is mounted on a vehicle. As shown in Fig. 1, the vehicle glass 1 according to this embodiment is mounted on a vehicle V. The vehicle glass 1 is a window member that is applied to the windshield of the vehicle V. That is, the vehicle glass 1 is used as the front window of the vehicle V, in other words, as a windshield. A far-infrared camera CA1 and a visible light camera CA2 are mounted inside (interior of) the vehicle V. Note that the inside (interior of) the vehicle V refers to, for example, the interior of the vehicle where the driver's seat is located.

[0011] The vehicle glass 1, the far-infrared camera CA1, and the visible light camera CA2 constitute a camera unit 100 according to this embodiment. The far-infrared camera CA1 is a camera that detects far-infrared rays and captures a thermal image of the exterior of the vehicle V by detecting far-infrared rays from outside the vehicle V. The visible light camera CA2 is a camera that detects visible light and captures an image of the exterior of the vehicle V by detecting visible light from outside the vehicle V. In addition to the far-infrared camera CA1 and the visible light camera CA2, the camera unit 100 may further include, for example, LiDAR or millimeter-wave radar. Here, far-infrared rays refer to, for example, electromagnetic waves having a wavelength in the range of 8 μm to 13 μm, and visible light refers to, for example, electromagnetic waves having a wavelength in the range of 360 nm to 830 nm. In addition, far-infrared rays may refer to electromagnetic waves having a wavelength in the range of 8 μm to 12 μm.

[0012] (Vehicle Glass) FIG. 2 is a schematic plan view of a vehicle glass according to this embodiment. FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 4 is a cross-sectional view taken along line B-B in FIG. 2. As shown in FIG. 2, hereinafter, the upper edge of the vehicle glass 1 will be referred to as an upper edge portion 1a, the lower edge as a lower edge portion 1b, one side edge as a side edge portion 1c, and the other side edge as a side edge portion 1d. The upper edge portion 1a is an edge portion located on the upper side in the vertical direction when the vehicle glass 1 is installed in a vehicle V. The lower edge portion 1b is an edge portion located on the lower side in the vertical direction when the vehicle glass 1 is installed in a vehicle V. The side edge portion 1c is an edge portion located on one side when the vehicle glass 1 is installed in a vehicle V. The side edge portion 1d is an edge portion located on the other side when the vehicle glass 1 is installed in a vehicle V.

[0013] Hereinafter, among directions parallel to the surface of the vehicle glass 1, the direction from the upper edge 1a to the lower edge 1b is referred to as the Y direction, and the direction from the side edge 1c to the side edge 1d is referred to as the X direction. In this embodiment, the X direction and the Y direction are perpendicular to each other. The direction perpendicular to the surface of the vehicle glass 1, i.e., the thickness direction of the vehicle glass 1, is referred to as the Z direction. For example, when the vehicle glass 1 is installed in a vehicle V, the Z direction is the direction from the exterior side to the interior side of the vehicle V. The X direction and the Y direction run along the surface of the vehicle glass 1. However, if the surface of the vehicle glass 1 is curved, for example, the X direction and the Y direction may be directions tangent to the surface of the vehicle glass 1 at the center point O of the vehicle glass 1. The center point O is the center position of the vehicle glass 1 when the vehicle glass 1 is viewed from the Z direction.

[0014] The vehicle glass 1 is formed with a light-transmitting region A1 and a light-shielding region A2. The light-transmitting region A1 is a region that occupies the central part of the vehicle glass 1 when viewed from the Z direction. The light-transmitting region A1 is a region that ensures the driver's field of vision. The light-transmitting region A1 is a region that transmits visible light. The light-shielding region A2 is a region that is formed around the light-transmitting region A1 when viewed from the Z direction. The light-shielding region A2 is a region that blocks visible light. Within the light-shielding region A2a, which is the portion of the light-shielding region A2 on the upper edge portion 1a side, a far-infrared light-transmitting region B and a visible light-transmitting region C are formed.

[0015] The far-infrared transmitting region B is a region that transmits far-infrared rays and is a region where the far-infrared camera CA1 is provided. That is, the far-infrared camera CA1 is provided at a position that overlaps with the far-infrared transmitting region B when viewed from the optical axis direction of the far-infrared camera CA1. The visible light transmitting region C is a region that transmits visible light and is a region where the visible light camera CA2 is provided. That is, the visible light camera CA2 is provided at a position that overlaps with the visible light transmitting region C when viewed from the optical axis direction of the visible light camera CA2.

[0016] In this way, the light-shielding region A2 has the far-infrared transmitting region B and the visible light transmitting region C formed therein, so that the light-shielding region A2 blocks far-infrared rays except in the region where the far-infrared transmitting region B is formed, and blocks visible light except in the region where the visible light transmitting region C is formed. The far-infrared transmitting region B and the visible light transmitting region C are surrounded by the light-shielding region A2a. Providing the light-shielding region A2a around the periphery in this way is preferable because it protects the various sensors from sunlight. It is also preferable from the viewpoint of design because the wiring of the various sensors is not visible from outside the vehicle.

[0017] 3 , the vehicle glass 1 includes a glass substrate 12 (first glass substrate), a glass substrate 14 (second glass substrate), an intermediate layer 16, and a light-shielding layer 18. The vehicle glass 1 has the glass substrate 12, the intermediate layer 16, the glass substrate 14, and the light-shielding layer 18 laminated in this order in the Z direction. The glass substrate 12 and the glass substrate 14 are fixed (bonded) to each other via the intermediate layer 16.

[0018] The glass substrates 12, 14 may be made of, for example, soda-lime glass, borosilicate glass, aluminosilicate glass, or the like. The intermediate layer 16 is an adhesive layer that bonds the glass substrates 12, 14 together. The intermediate layer 16 may be made of, for example, a modified polyvinyl butyral (hereinafter also referred to as PVB) material, an ethylene-vinyl acetate copolymer (EVA)-based material, a urethane resin material, or a vinyl chloride resin material. More specifically, the glass substrate 12 includes one surface 12A and another surface 12B, and the other surface 12B is in contact with one surface 16A of the intermediate layer 16 and fixed (adhered) to the intermediate layer 16. The glass substrate 14 includes one surface 14A and another surface 14B, and the one surface 14A is in contact with the other surface 16B of the intermediate layer 16 and fixed (adhered) to the intermediate layer 16. As described above, the vehicle glass 1 is a laminated glass in which the glass substrate 12 and the glass substrate 14 are laminated together. However, the vehicle glass 1 is not limited to a laminated glass, and may be configured to include, for example, only one of the glass substrate 12 and the glass substrate 14. In this case, the intermediate layer 16 may not be provided. Hereinafter, when there is no need to distinguish between the glass substrates 12 and 14, they will be referred to as the glass substrate 10.

[0019] The light-shielding layer 18 includes one surface 18A and the other surface 18B, and the one surface 18A is in contact with and fixed to the other surface 14B of the glass substrate 14. The light-shielding layer 18 is a layer that blocks visible light. For example, a ceramic light-shielding layer or a light-shielding film can be used as the light-shielding layer. For example, a ceramic layer made of a conventionally known material, such as a black ceramic layer, can be used as the ceramic light-shielding layer. For example, a light-shielding polyethylene terephthalate (PET) film, a light-shielding polyethylene naphthalate (PEN) film, a light-shielding polymethyl methacrylate (PMMA) film, etc. can be used as the light-shielding film.

[0020] In the present embodiment, the side of the vehicle glass 1 on which the light-shielding layer 18 is provided is the interior side of the vehicle V (inside of the vehicle), and the side on which the glass substrate 12 is provided is the exterior side of the vehicle V (outside of the vehicle), but this is not limiting, and the light-shielding layer 18 may be on the exterior side of the vehicle V. When the vehicle glass 1 is configured as a laminated glass of the glass substrates 12, 14, the light-shielding layer 18 may be formed between the glass substrate 12 and the glass substrate 14.

[0021] (Light-shielding region) The light-shielding region A2 is formed by providing the light-shielding layer 18 on the glass base 10. That is, the light-shielding region A2 is a region in which the glass base 10 is provided with the light-shielding layer 18. That is, the light-shielding region A2 is a region in which the glass base 12, the intermediate layer 16, the glass base 14, and the light-shielding layer 18 are laminated. On the other hand, the light-transmitting region A1 is a region in which the glass base 10 is not provided with the light-shielding layer 18. That is, the light-transmitting region A1 is a region in which the glass base 12, the intermediate layer 16, and the glass base 14 are laminated, and the light-shielding layer 18 is not laminated.

[0022] (Far-infrared ray transmitting region) As shown in FIG. 3 , the vehicle glass 1 has an opening 19 formed therein, penetrating from one surface (here, surface 12A) to the other surface (here, surface 14B) in the Z direction. A transparent member 20 is provided within the opening 19. The region where the opening 19 is formed and the transparent member 20 is provided is the far-infrared ray transmitting region B. That is, the far-infrared ray transmitting region B is a region where the opening 19 and the transparent member 20 disposed within the opening 19 are provided. Because the light-shielding layer 18 does not transmit far-infrared rays, the light-shielding layer 18 is not provided in the far-infrared ray transmitting region B. That is, the glass base 12, the intermediate layer 16, the glass base 14, and the light-shielding layer 18 are not provided in the far-infrared ray transmitting region B, and the transparent member 20 is provided in the formed opening 19. The transparent member 20 will be described later.

[0023] 4, the visible light transmitting region C is, similar to the light-transmitting region A1, a region in the Z direction where the glass base 10 does not include the light-shielding layer 18. In other words, the visible light transmitting region C is a region where the glass base 12, the intermediate layer 16, and the glass base 14 are laminated, and where the light-shielding layer 18 is not laminated.

[0024] As shown in FIG. 2 , the visible light transmission region C is preferably located near the far-infrared transmission region B. Specifically, the center of the far-infrared transmission region B as viewed from the Z direction is defined as center point OB, and the center of the visible light transmission region C as viewed from the Z direction is defined as center point OC. If the shortest distance between the far-infrared transmission region B (opening 19) and the visible light transmission region C as viewed from the Z direction is defined as distance L, distance L is preferably greater than 0 mm and less than 100 mm, and more preferably greater than 10 mm and less than 80 mm. Positioning the visible light transmission region C within this range relative to the far-infrared transmission region B enables the far-infrared camera CA1 and the visible light camera CA2 to capture images at nearby positions, while suppressing the amount of perspective distortion in the visible light transmission region C, allowing the visible light camera CA2 to capture appropriate images. Capturing images at nearby positions with the far-infrared camera CA1 and the visible light camera CA2 reduces the load when processing the data obtained from each camera and also optimizes the routing of power and signal cables.

[0025] As shown in Fig. 2, the visible light transmitting region C and the far-infrared transmitting region B are preferably positioned side by side in the X direction. That is, the visible light transmitting region C is preferably not positioned on the Y direction side of the far-infrared transmitting region B, but is preferably aligned with the far-infrared transmitting region B in the X direction. By arranging the visible light transmitting region C next to the far-infrared transmitting region B in the X direction, the visible light transmitting region C can be positioned near the upper edge portion 1a. Therefore, the driver's field of view in the light transmitting region A1 can be appropriately ensured.

[0026] (Transmitting Member) The transmitting member 20 provided in the far-infrared transmitting region B will now be described in detail. Fig. 5 is a schematic cross-sectional view of the transmitting member according to this embodiment. As shown in Fig. 5, the transmitting member 20 has a substrate 30 and a functional layer 40. The functional layer 40 has a foundation layer 44 formed on the substrate 30 and an outermost layer 42 formed on the foundation layer 44. That is, the transmitting member 20 is configured such that the foundation layer 44 is provided between the substrate 30 and the outermost layer 42 in the Z direction, and the foundation layer 44 bonds the substrate 30 and the outermost layer 42 together.

[0027] In this embodiment, the functional layer 40 is provided on at least one of the main surfaces 30a and 30b of the substrate 30. As shown in Fig. 5 , in this embodiment, the functional layer 40 is formed on the main surface 30a of the substrate 30. The main surface 30a is the surface of the substrate 30 facing away from the direction Z, and faces the exterior side of the vehicle when mounted on the vehicle glass 1. The main surface 30b is the surface of the substrate 30 facing the direction Z, and faces the interior side of the vehicle when mounted on the vehicle glass 1.

[0028] However, the functional layer 40 is not limited to being provided on either the main surface 30a or the main surface 30b of the substrate 30, and may be provided on both the main surface 30a and the main surface 30b. In this case, it is preferable that the functional layer 40 be provided on at least the main surface 30a.

[0029] In this embodiment, the transparent member 20 is provided in the light-blocking area A2 of the vehicle glass 1, which is a window member of the vehicle V, but is not limited thereto and may be provided in any exterior member of the vehicle V, such as an exterior member for a pillar of the vehicle V. Furthermore, the transparent member 20 is not limited to being provided in the vehicle V, and may be used for any purpose.

[0030] (Substrate) The substrate 30 is a member capable of transmitting far-infrared rays. The material of the substrate 30 is not particularly limited, but is preferably composed primarily of at least one selected from the group consisting of silicon (Si), germanium (Ge), zinc sulfide (ZnS), zinc selenide (ZnSe), and chalcogenide glass. That is, the substrate 30 may be composed primarily of Si, Ge, a ZnS compound, or chalcogenide glass. However, it is more preferable that the substrate 30 be composed primarily of Si. Here, the term "main component" refers to a content of the main component relative to the entire substrate 30 of 50 atomic % or more. The content of the main component in the substrate 30 is 50 atomic % to 100 atomic %, preferably 70 atomic % to 100 atomic %, and more preferably 90 atomic % to 100 atomic %. More preferably, the substrate 30 is composed of the main component alone, i.e., the content of the main component, excluding unavoidable impurities, is 100 atomic %. By using such a material for the substrate 30, it is possible to improve scratch resistance and peel resistance while appropriately transmitting far infrared rays. Note that peeling here refers to peeling of the functional layer 40 due to the application of a low-intensity external force that does not cause scratches to the functional layer 40.

[0031] A preferred composition of the chalcogenide glass is, in atomic %, Ge + Ga; 7% to 25%, Sb; 0% to 35%, Bi; 0% to 20%, Zn; 0% to 20%, Sn; 0% to 20%, Si; 0% to 20%, La; 0% to 20%, S + Se + Te; 55% to 80%, Ti; 0.005% to 0.3%, Li + Na + K + Cs; 0% to 20%, and F + Cl + Br + I; 0% to 20%. This glass preferably has a glass transition temperature (Tg) of 140°C to 550°C. Numerical ranges expressed as "to" refer to a range that includes the numbers before and after "to" as the lower and upper limits, respectively. The same meaning is used hereinafter.

[0032] The substrate 30 may contain a secondary component other than the primary component. For example, when the primary component of the substrate 30 is Si, the secondary component may include at least one of Ge, ZnS, ZnSe, and chalcogenide glass. Furthermore, when the primary component of the substrate 30 is Ge, the secondary component may include at least one of Si, ZnS, ZnSe, and chalcogenide glass.

[0033] The substrate 30 is a member capable of transmitting far-infrared rays. The substrate 30 preferably has an internal transmittance of 50% or more for light with a wavelength of 10 μm (far-infrared rays), more preferably 60% or more, and even more preferably 70% or more. Furthermore, the substrate 30 preferably has an average internal transmittance of 50% or more for light with a wavelength of 8 μm to 12 μm (far-infrared rays), more preferably 60% or more, and even more preferably 70% or more. By setting the internal transmittance at 10 μm and the average internal transmittance at 8 μm to 12 μm of the substrate 30 within this numerical range, far-infrared rays can be properly transmitted, thereby fully demonstrating the performance of, for example, the far-infrared camera CA1. The average internal transmittance here refers to the average value of the internal transmittance for light of each wavelength in the wavelength band (here, 8 μm to 12 μm).

[0034] The internal transmittance of the substrate 30 is the transmittance excluding the surface reflection loss on the incident side and the exit side, and is well known in the art, and may be measured by a commonly used method. The measurement is performed, for example, as follows.

[0035] A pair of flat samples (a first sample and a second sample) are prepared, each made of a substrate of the same composition but with different thicknesses. Both surfaces of the flat samples are parallel to each other and optically polished. The external transmittance including surface reflection loss of the first sample is T1, the external transmittance including surface reflection loss of the second sample is T2, the thickness of the first sample is Td1 (mm), and the thickness of the second sample is Td2 (mm), where Td1 < Td2 and ΔTd is the value obtained by subtracting Td1 from Td2. The internal transmittance τ at a thickness Tdx (mm) can be calculated using the following formula (1):

[0036] τ=exp[-Tdx×(lnT1-lnT2) / ΔTd]...(1)

[0037] The external transmittance of infrared light can be measured, for example, by a Fourier transform infrared spectrometer (manufactured by ThermoScientific, trade name: Nicolet iS10).

[0038] The refractive index of the substrate 30 with respect to light having a wavelength of 10 μm is preferably 1.5 to 4.0, more preferably 2.0 to 4.0, and even more preferably 2.2 to 3.5. Furthermore, the average refractive index of the substrate 30 with respect to light having a wavelength of 8 μm to 12 μm is preferably 1.5 to 4.0, more preferably 2.0 to 4.0, and even more preferably 2.2 to 3.5. Having the refractive index and average refractive index of the substrate 30 within this range allows for appropriate transmission of far-infrared light, thereby enabling the performance of, for example, the far-infrared camera CA1 to be fully demonstrated. The average refractive index here refers to the average value of the refractive index for light of each wavelength in the wavelength band (here, 8 μm to 12 μm). The refractive index can be determined, for example, by fitting an optical model using polarization information obtained from an infrared spectroscopic ellipsometer (IR-VASE-UT, manufactured by J.A. Woollam) and a spectral transmission spectrum obtained from a Fourier transform infrared spectrometer.

[0039] The thickness D1 of the substrate 30 is preferably 0.3 mm to 5 mm, more preferably 1 mm to 4 mm, and even more preferably 1.5 mm to 3 mm. When the thickness D1 is within this range, far-infrared rays can be appropriately transmitted while ensuring indentation hardness. The thickness D1 can also be considered as the length in the Z direction from the main surface 30a to the main surface 30b of the substrate 30.

[0040] (Functional Layer) The functional layer 40 is formed on the main surface 30a of the substrate 30. The functional layer 40 is a film composed of two or more layers. The functional layer 40 preferably has a layer structure of 2 to 20 layers, more preferably has a layer structure of 2 to 10 layers, and even more preferably has a layer structure of 2 to 3 layers. Note that the term "layer" as used herein refers to a layer that is continuously composed of the same material.

[0041] The functional layer 40 includes an outermost layer 42. The outermost layer 42 is the layer in the functional layer 40 that is located farthest from the substrate 30, i.e., the layer that is located closest to the vehicle exterior in this embodiment. In other words, the outermost layer 42 is the outermost layer of the transparent member 20 (the layer that is closest to the vehicle exterior in this embodiment) and is exposed to the outside. Details of the outermost layer 42 will be described later.

[0042] The functional layer 40 has an underlayer 44 closer to the substrate 30 than the outermost layer 42, i.e., between the outermost layer 42 and the substrate 30. The underlayer 44 is a layer provided between the outermost layer 42 and the substrate 30. In the example of FIG. 5, the underlayer 44 is in contact with the substrate 30. That is, the underlayer 44 can be said to be a layer provided in contact with the main surface 30a of the substrate 30. The underlayer 44 and the substrate 30 do not need to be in contact with each other, and for example, a layer that transmits far-infrared rays may be provided between the underlayer 44 and the substrate 30. In this case, the layer that transmits far-infrared rays may be made of Ge, ZnS, ZnSe, ZrO ２ It is preferable that the base layer 44 contains at least one selected from the group consisting of Si and Cu as a main component. Details of the base layer 44 will be described later.

[0043] The thickness of the functional layer 40 is preferably 200 nm or more, more preferably 200 nm or more and 3500 nm or less, and even more preferably 200 nm or more and 1500 nm or less. Having a thickness of the functional layer 40 within this range allows for appropriate transmission of far infrared rays, improving peel resistance while also improving scratch resistance. The thickness of the functional layer 40 can also be considered the length in the Z direction from the surface of the functional layer 40 on the Z direction side to the surface opposite the Z direction. In the example of FIG. 5 , the thickness of the functional layer 40 corresponds to the sum of thickness D2 and thickness D3. The thickness of the functional layer 40 can be measured using a scanning electron microscope (SU-70, manufactured by Hitachi High-Technologies Corporation) or a stylus-type step profiler (Dektak XT-S, manufactured by Bruker Japan).

[0044] (Outermost Layer) Next, the outermost layer 42 of the functional layer 40 will be described. The outermost layer 42 is a layer that forms the surface of the functional layer 40 opposite the substrate 30 (the vehicle exterior side in this example), and is a layer that forms the surface on the side exposed to the outside. In the example of Fig. 5, the outermost layer 42 is in contact with a base layer 44 provided on the substrate 30.

[0045] The outermost layer 42 contains C as its main component. The term "main component" here refers to a content of 50 atomic % or more of the outermost layer 42 as a whole. The main component content of the outermost layer 42 is preferably 50 atomic % to 100 atomic %, more preferably 80 atomic % to 100 atomic %, and even more preferably 90 atomic % to 100 atomic % of the outermost layer 42 as a whole. Furthermore, the outermost layer 42 most preferably contains 100 atomic % of the main component alone, i.e., excluding unavoidable impurities. By ensuring that the main component content of the outermost layer 42 falls within this range, the outermost layer 42 can appropriately transmit far infrared rays while improving scratch resistance. Furthermore, the outermost layer 42 is preferably a so-called diamond-like carbon (DLC) layer. This allows the outermost layer 42 to further improve scratch resistance.

[0046] The outermost layer 42 may contain Ge. The Ge content of the outermost layer 42 is from 0 to 15 atomic %, more preferably from 0 to 10 atomic %, and even more preferably from 0 to 7 atomic %, relative to the entire outermost layer 42. When the Ge content of the outermost layer 42 is in this range, it is possible to improve scratch resistance while appropriately transmitting far infrared rays.

[0047] The outermost layer 42 may further contain a secondary component other than the main components C and Ge. The secondary component is preferably an oxide that transmits far infrared rays, such as NiO. ｘ , ZnO, Bi ２ O ３ and CuO ｘ At least one of the following can be mentioned.

[0048] The components and content of the components in the outermost layer 42 can be measured, for example, by an X-ray photoelectron spectroscopy (XPS) device (Versa probe 1, manufactured by ULVAC-PHI, Inc.).

[0049] The thickness D2 of the outermost layer 42 is preferably 200 nm or more and 3500 nm or less, more preferably 200 nm or more and 1500 nm or less, and even more preferably 200 nm or more and 1300 nm or less. The thickness D2 can also be considered as the length in the Z direction from the surface of the outermost layer 42 on the Z direction side to the surface opposite the Z direction. Having the thickness D2 within this range allows for appropriate transmission of far infrared rays while improving peel resistance. The thickness D2 can be measured using a scanning electron microscope (SU-70, manufactured by Hitachi High-Technologies Corporation) or a stylus-type step profiler (Dektak XT-S, manufactured by Bruker Japan).

[0050] The surface of the outermost layer 42 opposite the substrate 30 is referred to as the surface 42a. The surface 42a is the surface exposed to the outside, and in this embodiment, it can be said to be the surface facing the vehicle exterior. In this case, the arithmetic mean roughness Ra (surface roughness) of the surface 42a of the outermost layer 42 is preferably 1.5 nm or less, more preferably 1.0 nm or less, even more preferably 0.8 nm or less, and most preferably 0.6 nm or less. By having the arithmetic mean roughness Ra of the surface 42a within this range, the dynamic friction coefficient and the change in surface roughness before and after abrasion can be reduced, and peel resistance can be further improved. Note that the arithmetic mean roughness Ra refers to the arithmetic mean roughness Ra specified in JIS B 0601:2001.

[0051] The outermost layer 42 is capable of transmitting far-infrared rays. The extinction coefficient of the outermost layer 42 with respect to light having a wavelength of 10 μm is preferably 0.1 or less, more preferably 0.08 or less, and even more preferably 0.05 or less. The extinction coefficient can be determined by fitting an optical model using polarization information obtained by an infrared spectroscopic ellipsometer (IR-VASE-UT, manufactured by J.A. Woollam Co.) and a spectral transmission spectrum obtained by a Fourier transform infrared spectrometer.

[0052] (Undercoat Layer) Next, the undercoat layer 44 will be described. The undercoat layer 44 is provided between the outermost layer 42 and the substrate 30. In the example of Fig. 5, the undercoat layer 44 is a layer that is in contact with both the outermost layer 42 and the substrate 30.

[0053] The base layer 44 contains C as a main component. Here, the term "main component" may refer to a content of C relative to the entire base layer 44 of 50 atomic % or more. The content of the main component relative to the entire base layer 44 is preferably 50 atomic % or more, more preferably 70 atomic % to 95 atomic % or less, and even more preferably 80 atomic % to 90 atomic % or less. By including such a main component, the base layer 44 can appropriately transmit far infrared rays while improving the peel resistance of the outermost layer 42.

[0054] The underlayer 44 contains Ge. The Ge content of the underlayer 44 is 0.1 atomic % or more and 30 atomic % or less, more preferably 5 atomic % or more and 30 atomic % or less, and even more preferably 10 atomic % or more and 20 atomic % or less. The Ge content of the underlayer 44 is preferably higher than the Ge content of the outermost layer 42. When the Ge content of the underlayer 44 satisfies this condition, peeling of the outermost layer 42 can be suppressed.

[0055] The underlayer 44 may contain a secondary component other than the main components C and Ge. The secondary component is preferably an oxide that transmits far infrared rays, such as MgO, CuO, or the like. ｘ , NiO ｘ , ZrO ｘ and B ２ O ３ At least one of the following can be mentioned.

[0056] The components and content of the components of the underlayer 44 can be measured, for example, by an X-ray photoelectron spectroscopy (XPS) device (Versa probe 1, manufactured by ULVAC-PHI, Inc.).

[0057] The thickness D3 of the underlayer 44 is preferably 10 nm or more and 500 nm or less, more preferably 20 nm or more and 500 nm or less, and even more preferably 40 nm or more and 450 nm or less. Having the thickness of the underlayer 44 within this range allows for appropriate adhesion between the substrate 30 and the intermediate layer 34 while appropriately suppressing reflection of far-infrared rays. The thickness D3 of the underlayer 44 can also be considered the length in the Z direction from the surface of the underlayer 44 facing the Z direction to the surface opposite the Z direction. The ratio of the thickness D3 of the underlayer 44 to the thickness D2 of the outermost layer 42 is preferably 5% or more and 300% or less, more preferably 10% or more and 300% or less, and even more preferably 25% or more and 200% or less. Having the thickness D3 within this range allows for appropriate transmission of far-infrared rays and suppresses peeling of the outermost layer 42. The thickness D3 can be measured using a scanning electron microscope (SU-70, manufactured by Hitachi High-Technologies Corporation) or a stylus-type step gauge (Dektak XT-S, manufactured by Bruker Japan).

[0058] The base layer 44 is capable of transmitting far-infrared rays. The base layer 44 preferably has an extinction coefficient for light with a wavelength of 10 μm of 0.1 or less, more preferably 0.05 or less, and even more preferably 0.03 or less. When the extinction coefficient is in this range, far-infrared rays can be transmitted appropriately.

[0059] (Characteristics of the Transmissive Member) The characteristics of the transmissive member 20 configured as above will be described below.

[0060] (Transmittance) The transmittance of the transparent member 20 for light with a wavelength of 10 μm is preferably 50% or more, more preferably 65% ​​or more, and even more preferably 75% or more. Furthermore, the average transmittance of the transparent member 20 for light with a wavelength of 8 μm or more and 12 μm or less is preferably 50% or more, more preferably 60% or more, and even more preferably 65% ​​or more. Having the transmittance and average transmittance within this range allows the transparent member to properly function. Note that the average transmittance is the average value of the transmittance for light of each wavelength in the wavelength band (here, 8 μm or more and 10 μm or less). The transmittance can be measured, for example, using a Fourier transform infrared spectrophotometer (Spectrum 3, manufactured by PerkinElmer).

[0061] (Reflectance) The reflectance of the transparent member 20 for light with a wavelength of 10 μm is preferably 10% or less, more preferably 5% or less. Furthermore, the average reflectance of the transparent member 20 for light with a wavelength of 8 μm or more and 12 μm or less is preferably 10% or less, more preferably 8% or less, and even more preferably 5% or less. Having the reflectance and average reflectance within these ranges allows the transparent member to properly function. Note that the average reflectance is the average value of the reflectance for light of each wavelength in the wavelength band (here, 8 μm or more and 10 μm or less). The reflectance can be measured, for example, using a Fourier transform infrared spectrophotometer (Spectrum 3, manufactured by PerkinElmer).

[0062] (Average Absorbance) The average absorbance of the transparent member 20 in the thickness direction for light having a wavelength of 8 μm or more and 10 μm or less is preferably 35% or less, more preferably 30% or less, and even more preferably 20% or less. The average absorbance of the transparent member 20 can be calculated based on the law of conservation of energy by subtracting the average transmittance and the average reflectance of the transparent member 20 from 100%.

[0063] The indentation hardness of the surface 20A (i.e., the surface 42a of the outermost layer 42) of the transparent member 20 at an indentation depth of 20 nm to 100 nm is preferably 15 GPa or more, more preferably 18 GPa or more, more preferably 19 GPa or more, even more preferably 20 GPa or more, and most preferably 21 GPa or more. Having the indentation hardness of the surface 20A within this range allows for appropriate improvement in scratch resistance. The indentation hardness of the surface 20A refers to the indentation hardness (indentation hardness) measured by a nanoindenter using a nanoindenter at an indentation depth of 20 nm to 100 nm. More specifically, the indentation hardness is a value determined from the displacement-load curve from loading to unloading of the measuring indenter, and is specified in ISO 14577. The indentation hardness can be measured as follows. Specifically, a KLA iMicro nanoindenter is used to continuously measure the indentation depth h (nm) corresponding to the indentation load P (mN) throughout the entire process from the start of loading to unloading at the measurement point, and a P-h curve is created. Then, the indentation hardness H (GPa) is calculated from the created P-h curve using the following equation (2).

[0064] H=P / A...(2)

[0065] In equation (2), P is the indentation load (mN), and A is the projected area of ​​the indenter (μm ２In this embodiment, the indentation hardness H in the indentation depth range of 20 nm to 100 nm is defined as the indentation hardness of the surface 20A. That is, in this embodiment, it is preferable that the indentation hardness H satisfies the above range in the entire indentation depth range of 20 nm to 100 nm.

[0066] (Adhesion) In the transparent member 20, the adhesion of the functional layer 40 to the substrate 30 is preferably 135 mN or more, more preferably 150 mN or more, even more preferably 160 mN or more, particularly preferably 180 mN or more, and most preferably 200 mN or more. Having the adhesion of the functional layer 40 to the substrate 30 within this range can improve peel resistance. The adhesion of the functional layer 40 refers to the peel critical load value (critical damage load) measured by a micro-scratch test using a scratch tester. More specifically, the peel critical load value is a value determined from the relationship between the friction response signal intensity and the load from a load of 0 mN of the measuring indenter, and is specified in JIS R 3255-1997. The peel critical load value can be measured as follows. Specifically, using an ultrathin film nanoindenter (CSR5100, manufactured by RESCA), the load is linearly increased from 0 mN at a measurement point on the surface 20A (i.e., the surface 42a of the outermost layer 42), and the change in frictional force corresponding to the load is continuously measured as a friction response signal (speed signal), creating a friction response signal intensity-load curve. The minute changes in frictional force that occur during peeling are detected as a speed signal, and the point at which the friction response signal intensity first decreases with increasing load, i.e., the load at which peeling first occurs in the coating, can be measured as the critical peel load value. In this embodiment, the microscratch test is performed 10 times, and the average of the measured critical peel load values ​​is calculated as the adhesion strength of the functional layer 40 to the substrate 30.

[0067] (Shape of the Transparent Member) As shown in FIG. 3 , the exterior surface 20A of the transparent member 20 is preferably formed flush (i.e., continuous) with the exterior surface of the light-shielding region A2. In other words, the exterior surface 20A of the transparent member 20 is attached so as to be continuous with the surface 12A of the glass substrate 12. By making the surface 20A of the transparent member 20 continuous with the surface 12A of the glass substrate 12 in this manner, the wiping effect of the wiper can be prevented from being impaired. In addition, the presence of a step can be prevented from impairing the design of the vehicle V, and the risk of sand and dust accumulating on the step can be prevented. Furthermore, the transparent member 20 is preferably shaped to fit the curved surface shape of the vehicle glass 1 to which it is applied. The method for shaping the transparent member 20 is not particularly limited, but polishing or molding can be selected depending on the curved surface shape and the member.

[0068] The shape of the transparent member 20 is not particularly limited, but is preferably a plate-like shape that matches the shape of the opening 19. That is, for example, if the opening 19 is circular, the transparent member 20 is preferably disk-shaped (or cylindrical). From the standpoint of design, the surface shape of the transparent member 20 on the vehicle exterior side may be processed to match the curvature of the outer surface shape of the glass substrate 12. Furthermore, for reasons such as achieving both a wider viewing angle of the far-infrared camera CA1 and improved mechanical properties, the transparent member 20 may be lenticular. This configuration is preferable because far-infrared light can be efficiently collected even if the area of ​​the transparent member 20 is small. When the far-infrared transparent member 20 is lenticular, the number of lens-shaped transparent members 20 is preferably one to three, and typically two. Furthermore, it is particularly preferable that the lens-shaped transparent member 20 is pre-aligned and modularized, and integrated with a housing or bracket that adheres the far-infrared camera CA1 to the vehicle glass 1.

[0069] In the vehicle glass 1 of this embodiment, the area of ​​the opening 19 on the vehicle interior surface may be smaller than the area of ​​the opening 19 on the vehicle exterior surface, and the shape of the transparent member 20 may also be such that the area on the vehicle interior surface is smaller than the area on the vehicle exterior surface accordingly. This configuration improves the resistance and strength against impact when the transparent member 20 is pushed in from the vehicle exterior. Furthermore, if the vehicle glass 1 of this embodiment is a laminated glass including a glass substrate 12 located on the vehicle exterior side and a glass substrate 14 located on the vehicle interior side, the opening 19 is formed by overlapping the opening 12a of the glass substrate 12 and the opening 14a of the glass substrate 14. In this case, the area of ​​the opening 12a of the glass substrate 12 may be larger than the area of ​​the opening 14a of the glass substrate 14, and a transparent member 20 matching the size of the opening 12a of the glass substrate 12 may be disposed within the opening 12a of the glass substrate 12. In another embodiment (not shown), the area of ​​the opening 12a of the glass substrate 12 may be made smaller than the area of ​​the opening 14a of the glass substrate 14, and the transparent member 20 may be disposed within the opening 12a of the glass substrate 12. This configuration allows the accuracy of aligning the opening 19 when the glass substrate 12 (on the vehicle exterior side) and the glass substrate 14 are laminated with the intermediate layer 16, thereby improving the processing yield. In yet another embodiment (not shown), the area of ​​the opening 12a of the glass substrate 12 and the area of ​​the opening 14a of the glass substrate 14 may be made the same, and the transparent member 20 may be disposed within the opening 12a of the glass substrate 12. In this configuration, the glass substrate 12 and the glass substrate 14 are laminated in advance with the intermediate layer 16 interposed therebetween, and the opening 19 is then formed in the laminated glass structure all at once. By forming the opening 19 in the laminated glass structure, the process load for aligning the openings is not imposed and the number of processing steps can be further reduced, thereby lowering manufacturing costs, compared to when an opening is provided in each of the glass substrates 12 (exterior side of the vehicle) and 14 (interior side of the vehicle). The relationship in size between the opening in the glass substrate 12 and the opening in the glass substrate 14 can be appropriately selected taking the above-mentioned advantages into consideration.

[0070] As shown in FIG. 3 , the length d1 of the longest straight line connecting any two points on the exterior surface of the transparent member 20 is preferably 80 mm or less. The length d1 is more preferably 70 mm or less, and even more preferably 65 mm or less. The length d1 is preferably 60 mm or more. As shown in FIG. 3 , the length d2 of the longest straight line connecting any two points on the exterior surface of the opening 19 in the far-infrared transmitting region B is preferably 80 mm or less. The length d2 is more preferably 70 mm or less, and even more preferably 65 mm or less. The length d2 is preferably 60 mm or more. The length d2 can also be considered the length of the longest straight line connecting any two points on the outer periphery of the opening 19 on the exterior surface (surface 12A) of the vehicle glass 1. By setting the length d1 of the transparent member 20 and the length d2 of the opening 19 within this range, a decrease in the strength of the vehicle glass 1 can be suppressed, and the amount of perspective distortion around the opening 19 can also be suppressed. Note that, when the shape of the vehicle exterior surface of the transparent member 20 is circular, the lengths d1 and d2 are lengths corresponding to the diameter of the vehicle exterior surface. Furthermore, the lengths d1 and d2 here refer to the lengths of the vehicle glass 1 in a state in which it is mounted on the vehicle V. For example, when the glass is bent into a shape to be mounted on the vehicle V, the lengths d1 and d2 are the lengths in a state after bending. The same applies to the descriptions of dimensions and positions other than the lengths d1 and d2 unless otherwise specified.

[0071] (Another Example 1) Next, another example of the transparent member 20 will be described. FIG. 6 is a schematic cross-sectional view of a transparent member according to another example of this embodiment. In the above description, as shown in FIG. 5, the functional layer 40 has a two-layer structure in which, from the base material 30 side, the base layer 44 and the outermost layer 42 are laminated, but this is not limited thereto. The functional layer 40 may also have a structure in which intermediate layers 46a to 46d are laminated between the base layer 44 and the outermost layer 42. An example of this layer structure will be specifically described below.

[0072] In this example, the functional layer 40 is stacked in the following order from the substrate 30 toward the outermost layer 42: the base layer 44 and the intermediate layers 46a-46d. The intermediate layers 46a-46d are primarily composed of carbon and have different Ge contents compared to the base layer 44 and the outermost layer 42. The Ge contents of the intermediate layers 46a-46d are preferably higher than the Ge content of the outermost layer 42 and lower than the Ge content of the base layer 44. In this case, the Ge contents of the layers included in the functional layer 40 are preferably lowest in the outermost layer 42 and highest in the base layer 44, with the Ge contents decreasing toward the outermost layer 42 (opposite the direction Z). The characteristics of the intermediate layers 46a-46d are similar to those of the outermost layer 42 described above, except for the Ge content, and therefore will not be described here. The number of intermediate layers between the base layer 44 and the outermost layer 42 is not limited to four as shown in FIG. 6, but may be more or less than four.

[0073] (Other Example 2) In the above description, the underlayer 44 is in contact with the substrate 30, but this is not limiting, and another film may be formed between the substrate 30 and the functional layer 40. For example, one or more other far-infrared-transmitting layers, such as an anti-reflection layer or a hue-adjusting layer, may be provided between the underlayer 44 and the substrate 30.

[0074] (Anti-reflection layer) The anti-reflection layer is a layer that suppresses reflection of far infrared rays. The anti-reflection layer may have any configuration, for example, a configuration in which low refractive index layers and high refractive index layers are alternately stacked. An example of this layer configuration will be specifically described below.

[0075] In this example, the antireflection layer is alternately laminated in the order of low refractive index layer and high refractive index layer from the substrate 30 side toward the underlayer 44. In this case, it is preferable that, of the layers between the substrate 30 and the underlayer 44, the layer closest to the substrate 30 (the layer in contact with the substrate 30) is a low refractive index layer, and the layer closest to the underlayer 44 (the layer in contact with the underlayer 44) is a low refractive index layer. For example, from the substrate 30 side toward the underlayer 44, a low refractive index layer, a high refractive index layer, and a low refractive index layer are laminated in this order. However, the number of low refractive index layers and high refractive index layers between the substrate 30 and the underlayer 44 is not particularly limited.

[0076] (Low Refractive Index Layer) The low refractive index layer will now be described. The refractive index of the low refractive index layer of the antireflection layer for light with a wavelength of 8 μm is preferably lower than the refractive index of the substrate 30 or the high refractive index layer for light with a wavelength of 8 μm. In other words, it can be said that the functional layer 40 functions as part of the low refractive index layer.

[0077] The low refractive index layer is preferably capable of transmitting far infrared rays. The low refractive index layer preferably has an extinction coefficient for light with a wavelength of 8 μm of 0.10 or less, more preferably 0.05 or less, and even more preferably 0.04 or less.

[0078] The low refractive index layer may be made of any material that transmits far infrared rays, but examples thereof include ZnS, ZnSe, C, MgO ｘ or NiO ｘ It is preferable that the main component is either C or NiO. ｘ The low refractive index layer has a content of the main component of 50 atomic % or more and 100 atomic % or less, preferably 70 atomic % or more and 100 atomic % or less, and more preferably 90 atomic % or more and 100 atomic % or less.

[0079] The low refractive index layer may contain a secondary component other than the main component, which is preferably an oxide that transmits far infrared rays, such as at least one of silicon (Si), germanium (Ge), zinc sulfide (ZnS), and zinc selenide (ZnSe).

[0080] (High Refractive Index Layer) The characteristics of the high refractive index layer will be described below. The refractive index of the high refractive index layer for light with a wavelength of 8 μm is higher than the refractive index of the low refractive index layer for light with a wavelength of 8 μm. The ratio of the refractive index of the low refractive index layer for light with a wavelength of 8 μm to the refractive index of the high refractive index layer for light with a wavelength of 8 μm is preferably 30% or more and less than 100%, more preferably 50% or more and 90% or less, and even more preferably 60% or more and 80% or less. The refractive index of the high refractive index layer for light with a wavelength of 8 μm is preferably 2.5 or more, more preferably 2.5 or more and 4.5 or less, and even more preferably 3.0 or more and 4.2 or less. When the refractive index of the high refractive index layer is within this numerical range, far infrared rays can be appropriately transmitted.

[0081] The high refractive index layer is preferably capable of transmitting far infrared rays. The high refractive index layer preferably has an extinction coefficient for light with a wavelength of 8 μm of 0.10 or less, more preferably 0.05 or less, and even more preferably 0.04 or less.

[0082] The high refractive index layer may be composed of any material that transmits far infrared rays, but preferably contains at least one of silicon (Si), germanium (Ge), and silicon oxide as its main component, and more preferably contains Ge as its main component. The high refractive index layer has a main component content of 50 atomic % to 100 atomic %, preferably 70 atomic % to 100 atomic %, and more preferably 90 atomic % to 100 atomic %. Furthermore, the high refractive index layer is preferably composed of a single main component. When the main component content is within this range, the high refractive index layer can adequately transmit far infrared rays.

[0083] The high refractive index layer may contain a secondary component other than the main component. The secondary component is preferably a material that transmits far infrared rays, such as at least one of silicon (Si), germanium (Ge), and silicon oxide.

[0084] (Hue Adjusting Layer) The hue adjusting layer is a layer for ensuring design by reducing the difference in reflectance (reflectance dispersion) for visible light of different wavelengths and suppressing interference colors of the transmissive member 20 .

[0085] The hue-adjusting layer is capable of transmitting far-infrared rays. The hue-adjusting layer preferably has an extinction coefficient of 0.4 or less, more preferably 0.2 or less, and even more preferably 0.1 or less, for light with a wavelength of 10 μm. The extinction coefficient within this range allows the far-infrared rays to be transmitted appropriately.

[0086] The hue adjustment layer may have any structure. It may be a laminate including a first layer and a second layer provided on the outermost layer 42 side of the first layer, or multiple laminates of the first and second layers may be stacked. The hue adjustment layer is preferably a layer in which the first and second layers are alternately stacked in a number of 2n (n is a natural number greater than or equal to 1) layers from the substrate 30 side. The thickness ratio of each layer in the hue adjustment layer is preferably such that the layer with a lower refractive index for light with a wavelength of 550 nm (visible light) has a higher thickness. By setting the stacking order and number of layers in the hue adjustment layer within this range, it is possible to suppress reflection and dispersion of visible light and make the transmissive member 20 less noticeable. The hue adjustment layer may also be a layer whose refractive index for light with a wavelength of 550 nm (visible light) is different from that of both the outermost layer 42 and the underlayer 44. The hue-adjusting layer preferably has a refractive index of 2.2 to 2.5 for light with a wavelength of 550 nm (visible light), and more preferably 2.3 to 2.4 for light with a wavelength of 550 nm. When the refractive index of the hue-adjusting layer for visible light falls within this range, it is possible to suppress the reflection and dispersion of visible light, and make the transparent member 20 less noticeable.

[0087] (Other Example 3) In the above description, no layer is provided on the other main surface 30b side of the substrate 30. However, this is not limiting, and one or more layers that transmit far-infrared rays, such as the functional layer 40, the outermost layer 42, the base layer 44, the anti-reflection layer, and the hue-adjusting layer, as described above, may be provided on the other main surface 30b side of the substrate 30.

[0088] (Method for manufacturing the transparent member) Any method for manufacturing the transparent member 20 may be used, but the following describes one example of a method for manufacturing the transparent member 20. In this embodiment, the transparent member 20 is manufactured by preparing a substrate 30 after plasma cleaning and performing a lamination step in which the underlayer 44 and the outermost layer 42 are laminated in this order.

[0089] In the lamination step, the underlayer 44 and the outermost layer 42 may be laminated by any method, for example, the underlayer 44 and the outermost layer 42 may be laminated by sputtering. In this case, any sputtering method may be used, for example, at least one of magnetron sputtering, reactive sputtering, and post-reactive sputtering methods such as post-nitriding sputtering, post-oxidation sputtering, post-fluoridation sputtering, and post-sulfidation sputtering may be used, and the use of post-reactive sputtering is preferable in that it increases the options for materials that can be laminated.

[0090] 7 is a schematic diagram of a manufacturing apparatus for a transmitting member according to this embodiment. When the underlayer 44 and the outermost layer 42 are laminated by sputtering, a sputtering apparatus 200 shown in FIG.

[0091] Here, a description will be given of the configuration of the sputtering apparatus 200. As shown in Fig. 7, the sputtering apparatus 200 has a power supply 211, a vacuum chamber 215, a substrate holder 220, and a cathode 233.

[0092] The power supply 211 is a power supply for the sputtering apparatus 200. In the example of FIG. 7 , one end of the power supply 211 is connected to a cathode 233 (described later), and the other end is grounded. The power supply 211 is, for example, a DC power supply, an RF (Radio Frequency) power supply, a DC pulse power supply, a high-power impulse magnetron sputtering (HiPIMS) power supply, or an alternating current (AC) power supply. Here, the power supply 211 is preferably a HiPIMS power supply, an AC power supply, or a DC pulse power supply, more preferably a HiPIMS power supply or an AC power supply, and even more preferably a HiPIMS power supply. The HiPIMS power supply can apply a constant power and a temporal pulsed power, enabling sputtering (HiPIMS) in which a large amount of power is applied in a short time. This allows for the deposition of a layer with higher hardness. In this disclosure, the HiPIMS condition is defined as a condition in which the pulsed power is at least 10 times the time average of the applied power.

[0093] The vacuum chamber 215 provides a space for forming a layer on the substrate 30 to be laminated, and the substrate holder 220 and the cathode 233 are housed in the vacuum chamber 215 .

[0094] The substrate holder 220 serves to hold the substrate 30 to be laminated. The substrate holder 220 is configured in a disk shape and has a central axis AX that extends in a direction perpendicular to the disk, that is, in the Z direction in FIG.

[0095] The cathode 233 has a role of holding the targets 231 and 231A for deposition. The cathode 233 is provided so that the targets 231 and 231A face the substrate 30 in the Z direction. The configurations of the targets 231 and 231A will be described later.

[0096] A deposition method using the sputtering apparatus 200 will be described below. First, the substrate 30 is placed at a position perpendicular to the axis AX of the disk of the substrate holder 220. The substrate 30 has a plate-like shape. The substrate 30 is held by the substrate holder 220 so that the main surface 30a, on which a layer is formed, faces the targets 231 and 231A. Next, the vacuum chamber 215 is evacuated, and the substrate holder 220 rotates around the central axis AX as shown by arrow F in FIG. 7 . This causes the substrate 30 to also rotate around the central axis AX. Next, the power source 211 sputters the targets 231 and 231A. This causes the deposition material to be emitted from the targets 231 and 231A. Because the substrate 30 rotates together with the substrate holder 220, it comes into contact with plasma, which is the deposition material emitted from the targets 231 and 231A, with each rotation. Therefore, the lamination material is sequentially deposited on the main surface 30 a of the substrate 30 from the targets 231 and 231A.

[0097] FIG. 8 is a plan view showing a target used in the manufacturing apparatus shown in FIG. 7 . When laminating a layer made of C, a graphite target 231 alone is placed on the cathode 233 for sputtering. On the other hand, when laminating a layer containing C and Ge, a target 231A shown in FIG. 8 can be placed for sputtering. The target 231A is a target in which a plurality of Ge targets 232 are attached to a graphite target 231. When viewed from above in the Z direction, the Ge targets 232 are placed so that their geometric centers 232a overlap the circumference P of a circle (pitch circle) centered on the geometric center 231a of the graphite target 231. Furthermore, for example, three Ge targets 232 are placed so that the distance between their geometric centers 232a is equal. This allows the formation of a layer containing C and Ge. Here, the Ge content of the layer containing C and Ge was adjusted by changing the diameter R2 and pitch circle diameter R3 (PCD: Pitch Circle Diameter) of the Ge target 232. This changes the area of ​​the Ge target 232 in region E (erosion region) where target atoms are emitted intensively, thereby adjusting the Ge concentration in the plasma and the Ge content of the layer containing C and Ge. Region E is shown as a hatched region in FIG. 8.

[0098] In the above description, a layer containing C and Ge is formed by providing a target 232 made of Ge on a graphite target 231 and performing sputtering. However, the method for laminating a layer containing C and Ge using the apparatus shown in Fig. 7 is not limited to this. For example, a layer containing C and Ge may be formed by arranging the graphite target 231 and the target 232 made of Ge in the vacuum chamber 215 facing the substrate 30 and simultaneously sputtering C and Ge onto the substrate 30. Alternatively, the graphite target 231 and the target 232 made of Ge may be arranged in the vacuum chamber 215 facing the surface of the substrate holder 220 so as to be point-symmetric about the central axis AX of the substrate holder 220 when viewed in a plan view in the Z direction, and the substrate holder 220 may be rotated at high speed around the central axis AX to form a layer containing C and Ge. In this case, a layer containing C and Ge can be formed by alternately passing the substrate 30 in front of two types of targets 231, 232 at a speed such that the thickness of the layer deposited on the substrate 30 per rotation is smaller than the size of an atom.

[0099] 9 is a schematic diagram of a manufacturing apparatus for a transmitting member according to another example of this embodiment. When the underlayer 44 and the outermost layer 42 are laminated by sputtering, a sputtering apparatus 200A shown in FIG.

[0100] Here, the configuration of the sputtering apparatus 200A will be described. As shown in Fig. 9, the sputtering apparatus 200A has a vacuum chamber 215, a substrate holder 220A, and a stacking chamber 227. In this example, four stacking chambers 227 are formed, and here, the respective stacking chambers 227 are referred to as a first stacking chamber 227A, a second stacking chamber 227B, a third stacking chamber 227C, and a fourth stacking chamber 227D.

[0101] The vacuum chamber 215 provides a space for forming layers on the substrate 30 to be laminated, and the substrate holder 220A and each lamination chamber 227 are housed within the vacuum chamber 215 .

[0102] The substrate holder 220A serves to hold the substrates 30 to be laminated. The substrate holder 220A is cylindrical and has a central axis AX that extends vertically, i.e., in the Z direction in FIG. 9 . The substrate holder 220A is housed in the vacuum chamber 215 so that this central axis AX is positioned approximately in the center of the vacuum chamber 215. The substrate holder 220A also has an outer circumferential surface 223 that is centered on the central axis AX along the Z direction. A plurality of substrates 30 can be mounted on this outer circumferential surface 223 using fixing means such as bolts.

[0103] The vacuum chamber 215 is partitioned into individual stacking chambers 227. The first stacking chamber 227A is partitioned by two partition plates 229, one end of which is fixed to the side wall of the vacuum chamber 215. The other ends of both partition plates 229 are positioned toward the substrate holder 220A. Each partition plate 229 extends in the direction of the central axis AX of the substrate holder 220A. Therefore, the first stacking chamber 227A also extends in the direction of the central axis AX. A stacking target 230 is disposed on the side wall of the vacuum chamber 215 of the first stacking chamber 227A. An electrode (not shown) or the like is disposed on the back side of the target 230, i.e., on the side wall of the vacuum chamber 215. The second stacking chamber 227B, third stacking chamber 227C, and fourth stacking chamber 227D have the same configuration as the first stacking chamber 227A.

[0104] When performing deposition using the sputtering apparatus 200A, first, the substrate 30 is placed on the outer peripheral surface 223 of the substrate holder 220A. For example, in the example shown in FIG. 9 , ten substrates 30 are placed on the substrate holder 220A. Each substrate 30 has a plate-like shape. The substrate 30 is held by the substrate holder 220A such that the main surface 30a, on which a layer is formed, extends along the central axis AX of the substrate holder 220A. Next, the vacuum chamber 215 is evacuated, and the substrate holder 220A rotates around the central axis AX as indicated by arrow F in FIG. 9 . This causes the substrate 30 to also rotate around the central axis AX. Next, in each deposition chamber 227, sputtering is performed on the target 230. This causes deposition material to be released from the target 230 in each deposition chamber 227. In the first embodiment, the targets 230 are graphite targets and germanium targets. That is, for example, graphite targets are placed on the sidewalls of the vacuum chamber 215 in the first and third lamination chambers 227A and 227C, and germanium targets are placed on the sidewalls of the vacuum chamber 215 in the second and fourth lamination chambers 227B and 227D. Because the substrate 30 rotates together with the substrate holder 220A, it passes through the first to fourth lamination chambers 227A to 227D in sequence. Therefore, the lamination materials produced in each lamination chamber 227 are sequentially deposited on the main surface 30a of the substrate 30. Here, the substrate holder 220A rotates at high speed, and the thickness of the layer deposited per rotation is smaller than the atomic size. By alternately passing the substrate 30 in front of the two types of targets at this speed, a layer containing C and Ge can be deposited. Furthermore, the composition ratio of Ga and C can be adjusted by adjusting the magnitude and timing of the power applied to each target.

[0105] (Effects) As described above, the transparent member 20 according to the first aspect of the present disclosure includes a substrate 30 that transmits far-infrared rays and a functional layer 40 formed on at least one surface of the substrate 30. The functional layer 40 includes an outermost layer 42 and an underlayer 44 formed between the outermost layer 42 and the substrate 30. The underlayer 44 contains C as a main component. The Ge content of the underlayer 44 is 0.1 atomic % or more and 30 atomic % or less. The outermost layer 42 contains C as a main component. The Ge content of the outermost layer 42 is 15 atomic % or less. The Ge content of the underlayer 44 is greater than the Ge content of the outermost layer 42.

[0106] Here, in order to appropriately transmit light such as far-infrared rays, a layer containing Ge and C may be provided on the substrate 30 of the transparent member 20. However, if a layer containing Ge and C is provided as the outermost layer on the substrate 30 in this manner, sufficient scratch resistance may not be obtained. In contrast, in the transparent member 20 according to this embodiment, the substrate 30 and the outermost layer 42 containing C as a main component are further provided on the surface of the underlayer 44 containing C as a main component and further containing Ge. This improves the indentation hardness and the scratch resistance of the surface of the transparent member 20. Furthermore, in order to improve scratch resistance, a layer containing C as a main component may be provided on the substrate 30 of the transparent member 20. However, if a layer containing C as a main component is provided directly on the substrate 30 in this manner, sufficient peel resistance may not be obtained. In contrast, in the transparent member 20 according to this embodiment, the underlayer 44 containing C as a main component and further containing Ge is provided between the substrate 30 and the outermost layer 42 containing C as a main component. This can improve the adhesive strength and the peel resistance of the surface of the transmitting member 20 .

[0107] The transparent member 20 according to the second aspect of the present disclosure is the transparent member 20 according to the first aspect, in which the ratio of the thickness D3 of the base layer 44 to the thickness D2 of the outermost layer 42 is 5% or more and 300% or less. This allows the transparent member 20 to appropriately transmit far infrared rays and suppress peeling of the outermost layer 42.

[0108] The transparent member 20 according to a third aspect of the present disclosure is the transparent member 20 according to the first or second aspect, wherein the arithmetic mean roughness Ra of the surface 42 a of the outermost layer 42 opposite to the substrate 30 is 1.5 nm or less. This reduces the coefficient of dynamic friction and the change in surface roughness before and after scratching, and can further improve the peel resistance of the surface of the transparent member 20.

[0109] The transparent member 20 according to a fourth aspect of the present disclosure is the transparent member 20 according to any one of the first to third aspects, in which the adhesive force of the functional layer 40 to the substrate 30 measured by a micro-scratch test is 135 mN or more. This makes the surface of the transparent member 20 more sufficiently resistant to peeling.

[0110] A transparent member 20 according to a fifth aspect of the present disclosure is the transparent member 20 according to any one of the first to fourth aspects, wherein the indentation hardness of the surface 42 a of the outermost layer 42 is 18 GPa or more. This makes the scratch resistance of the surface of the transparent member 20 more sufficient.

[0111] A transparent member 20 according to a sixth aspect of the present disclosure is the transparent member 20 according to any one of the first to fifth aspects, in which the thickness of the functional layer is 200 nm or more. Even in this case, sufficient adhesive strength can be obtained, and therefore the scratch resistance of the surface of the transparent member 20 can be improved while improving peel resistance.

[0112] The transparent member 20 according to a seventh aspect of the present disclosure is the transparent member 20 according to any one of the first to sixth aspects, in which the average absorptance of light in the thickness direction at wavelengths of 8 μm or more and 10 μm or less is 10% or less, thereby achieving sufficient transmittance for light such as far infrared rays.

[0113] A transparent member 20 according to an eighth aspect of the present disclosure is the transparent member 20 according to any one of the first to seventh aspects, wherein the base material contains at least one material selected from the group consisting of Si, Ge, ZnS, ZnSe, and chalcogenide glass, thereby enabling the appropriate transmission of light while improving scratch resistance and peel resistance.

[0114] A transparent member 20 according to a ninth aspect of the present disclosure is the transparent member 20 according to any one of the first to eighth aspects, wherein the Ge content of the outermost layer is 10 atomic % or less, thereby enabling appropriate light transmission, improved peel resistance, and further improved scratch resistance.

[0115] EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. Table 1 shows the layer structure of the transmitting member of each example and the evaluation results.

[0116]

[0117] Example 1 In Example 1, a layer containing C and Ge (Ge-containing layer) as an underlayer and a layer of C (C layer) as an outermost layer were formed on one surface of a Si (manufactured by Atopical Corp.) substrate under the following deposition conditions: a base layer; and a layer of C (C layer). These were formed in this order using the sputtering apparatus 200 shown in FIG. 7 under the following pulse conditions as HiPIMS conditions, to obtain a transparent member. In Example 1, a layer containing 80 atomic % C and 20 atomic % Ge was formed as the underlayer. Here, in the deposition step of the Ge-containing layer, sputtering was performed using the target 231A shown in FIG. 8. The thicknesses of the substrate, underlayer, and outermost layer were as shown in Table 1. The ratio of the thickness of the underlayer to the thickness of the outermost layer was calculated as the thickness ratio (outermost layer / underlayer). The substrate thickness was measured using a digital caliper (manufactured by Mitutoyo Corporation, CD-15CX). The thickness of each of the underlayer and the outermost layer was measured using a scanning electron microscope (SU-70, manufactured by Hitachi High-Technologies Corporation).

[0118] (Ge-containing layer deposition conditions) Target: Graphite target (diameter: 5.08 cm, thickness: 3 mm) on which Ge target (diameter: 5 mm, thickness: 1 mm) was placed Pitch circle diameter: 40 mm Target-substrate distance: 80 mm Sputtering gas: Ar gas (flow rate: 26 sccm) Applied power: 0.1 kW Pulse conditions: Frequency 1000 Hz Duty ratio 5% Film formation pressure: 1.0 Pa

[0119] (Layer C deposition conditions) Target: graphite target (diameter: 5.08 cm, thickness: 3 mm) Distance between target and substrate: 80 mm Sputtering gas: Ar gas (flow rate: 26 sccm) Applied power: 0.1 kW Pulse conditions: frequency 1000 Hz, duty ratio 5% Film formation pressure: 1.0 Pa

[0120] The average absorption rate, indentation hardness, and adhesive strength of the obtained substrate of the transmitting member were measured by the following methods. The results are shown in Table 1.

[0121] The average absorptance was measured under the following conditions using the method described above. Here, the average absorptance was calculated by subtracting the measured average transmittance at wavelengths of 8 μm to 10 μm and the measured average reflectance at wavelengths of 8 μm to 10 μm from 100%. In other words, the average absorptance in Table 1 is the average absorptance for light with wavelengths of 8 μm to 10 μm. Fourier transform infrared spectrophotometer: Spectrum 3 (manufactured by PerkinElmer) Measurement wavelength band: 2.5 μm to 25 μm

[0122] The indentation hardness was measured under the following conditions using the method described above. Regarding the correlation between the depth method and the indentation hardness, the indentation hardness was averaged at 16 points to create a graph, and the value at which the indentation hardness was maximum at a point between 20 nm and 100 nm was taken as the indentation hardness of the film. Nanoindentation tester: iMicro type nanoindenter (manufactured by KLA Corporation) Indenter: Berkovich indenter Head: High-resolution head (InForce50) Measurement mode: Continuous stiffness measurement Maximum load: 1000 mN Strain rate: 0.2 s －１ Maximum load holding time: 2 seconds Poisson's ratio of sample: 0.25 Number of measurement points: 16 points

[0123] The adhesive strength was measured under the following conditions using the method described above. The adhesive strength was determined as the average of 10 critical loads measured. Ultra-thin film scratch tester: CSR5100 (RESCA) Stylus: Diamond (tip radius: 15 μm) Load increase rate: 5 mN / s Frequency (transverse direction): 45 Hz Amplitude (transverse direction): 50 μm Scratch speed: 10 μm / s Number of tests: 10

[0124] In Example 2, a transmission member was obtained under the same conditions as in Example 1, except that the thickness of the underlayer was set to the value shown in Table 1. The average absorption rate, indentation hardness, and adhesive force of the obtained transmission member were as shown in Table 1.

[0125] In Example 3, a transmission member was obtained under the same conditions as in Example 1, except that the diameter of the Ge target was 5 mm, the pitch circle diameter was 41.25 mm, and a layer containing 85 atomic % C and 15 atomic % Ge was formed as the underlayer. The average absorption coefficient, indentation hardness, and adhesion of the obtained transmission member were as shown in Table 1.

[0126] In Example 4, a transmission member was obtained under the same conditions as in Example 1, except that the diameter of the Ge target was 5 mm, the pitch circle diameter was 42 mm, and a layer containing 89 atomic % C and 11 atomic % Ge was formed as the underlayer. The average absorption coefficient, indentation hardness, and adhesion of the obtained transmission member were as shown in Table 1.

[0127] In Example 5, a transmission member was obtained under the same conditions as in Example 1, except that the diameter of the Ge target was 5 mm, the pitch circle diameter was 44 mm, and a layer containing 93 atomic % C and 7 atomic % Ge was formed as the outermost layer. The average absorption rate, indentation hardness, and adhesion force of the obtained transmission member were as shown in Table 1.

[0128] In Example 6, a transmission member was obtained under the same conditions as in Example 1, except that sputtering was performed using a DC power supply with an applied power of 0.1 kW, rather than using HiPIMS conditions. The average absorptivity, indentation hardness, and adhesive force of the obtained transmission member were as shown in Table 1.

[0129] In Example 7, a transparent member was obtained under the same conditions as in Example 1, except that the thickness of the underlayer was set as shown in Table 1 and sputtering was performed using a DC power supply with an applied power of 0.1 kW without using HiPIMS conditions. The average absorptivity, indentation hardness, and adhesive force of the obtained transparent member were as shown in Table 1.

[0130] In Example 8, a transparent member was obtained under the same conditions as in Example 1, except that no underlayer was formed, the diameter of the Ge target was 5 mm, the pitch circle diameter was 40 mm, and a layer containing 80 atomic % C and 20 atomic % Ge was formed as the outermost layer by sputtering using a DC power supply with an applied power of 0.1 kW without using HiPIMS conditions, and the thickness was set as shown in Table 1. The average absorptivity, indentation hardness, and adhesion of the obtained transparent member were as shown in Table 1.

[0131] In Example 9, a transmission member was obtained under the same conditions as in Example 1, except that no underlayer was formed and the thickness of the outermost layer was set as shown in Table 1. The average absorbance, indentation hardness, and adhesive force of the obtained transmission member were as shown in Table 1.

[0132] In Example 10, a transparent member was obtained under the same conditions as in Example 1, except that no underlayer was formed, no HiPIMS conditions were used, and sputtering was performed using a DC power supply with an applied power of 0.1 kW, to obtain the thickness of the outermost layer shown in Table 1. The average absorptivity, indentation hardness, and adhesive force of the obtained transparent member were as shown in Table 1.

[0133] As shown in Table 1, in Example 8 (Comparative Example), in which the Ge content of the outermost layer is greater than 15 atomic %, the indentation hardness is low and it is not possible to improve the scratch resistance. Also, as shown in Table 1, in Examples 9 and 10 (Comparative Examples), which do not have a Ge-containing underlayer, the adhesion is low and it is not possible to improve the peel resistance. On the other hand, in Examples 1 to 7 (Examples), in which the Ge content of the outermost layer is 15 atomic % or less and which have a Ge-containing underlayer, the indentation hardness is high and the adhesion is high, so it is possible to improve the scratch resistance and further improve the peel resistance.

[0134] As shown in Table 1, in Examples 6 and 7 (Examples) where sputtering was performed without HiPIMS conditions, the average absorptance of light with a wavelength of 8 μm or more and 10 μm or less did not reach 10% or less. On the other hand, in Examples 1 to 5 (Examples) where sputtering was performed under HiPIMS conditions, the average absorptance of light with a wavelength of 8 μm or more and 10 μm or less could reach 10% or less.

[0135] Although the embodiments of the present invention have been described above, the embodiments are not limited to the contents of these embodiments. Furthermore, the above-described components include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the scope of what is called equivalents. Furthermore, the above-described components can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the above-described embodiments.

[0136] DESCRIPTION OF SYMBOLS 1 Vehicle glass 10, 12, 14 Glass substrate 20 Transmitting member 30 Base material 40 Functional layer 42 Outermost layer 44 Base layer 46a to 46d Intermediate layer

Claims

1. A transmissive member comprising a substrate that transmits far-infrared rays and a functional layer formed on at least one surface of the substrate, the functional layer including an outermost layer and an underlayer formed between the outermost layer and the substrate, the underlayer containing C as a main component, the Ge content of the underlayer being 0.1 atomic % or more and 30 atomic % or less, the outermost layer containing C as a main component, the Ge content of the outermost layer being 15 atomic % or less, and the Ge content of the underlayer being greater than the Ge content of the outermost layer.

2. The transmissive member according to claim 1, wherein the ratio of the thickness of the underlayer to the thickness of the outermost layer is 5% or more and 300% or less.

3. The transmissive member according to claim 1 or 2, wherein the arithmetic mean roughness of the surface of the outermost layer on the side opposite to the substrate is 1.5 nm or less.

4. The transmissive member according to claim 1 or 2, wherein the adhesion of the functional layer to the substrate, measured by a micro scratch test, is 135 mN or more.

5. The transmissive member according to claim 1 or 2, wherein the indentation hardness of the surface of the outermost layer is 18 GPa or more.

6. The transmissive member according to claim 1 or 2, wherein the thickness of the functional layer is 200 nm or more.

7. The transmissive member according to claim 1 or 2, wherein the average absorption rate of light having a wavelength of 8 μm or more and 10 μm or less in the thickness direction is 10% or less.

8. The transmissive member according to claim 1 or 2, wherein the substrate contains at least one material selected from the group consisting of Si, Ge, ZnS, ZnSe, and chalcogenide glass.

9. The transmissive member according to claim 1 or 2, wherein the Ge content of the outermost layer is 10 atomic % or less.

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