Cover for Sensor and Sensor Module

Abstract

To provide a technique for suppressing a short circuit between a conductor and a heat generation film constituting a sensor cover.SOLUTION: A sensor cover 2 is provided in an opening of a housing 3 that accommodates a sensor 5. The sensor cover 2 includes a conductor 22 and a heat generation film 24 in a desired order from the outside of the housing 3 toward the inside of the housing 3. The conductor 22 is a conductive oxide. The conductor 22 and the heat generation film 24 are insulated from each other. The conductor 22 is electrically connected to the ground. The shortest distance Lmin between the conductor 22 and the heat generation film 24 is 2.0 μm or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a sensor cover and a sensor module.

Background Art

[0002] A sensor cover is provided at an opening of a housing that houses a sensor such as a LiDAR (Light Detection and Ranging) sensor. The sensor cover is, for example, a band-pass filter that transmits near-infrared rays and shields visible light. Patent Document 1 discloses a band-pass filter using a dielectric multilayer film.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The sensor cover may have a heating film to prevent snow accumulation, icing, or condensation. The heating film is electrically connected to a power source. The sensor cover may also have a conductive film separately from the heating film. The conductive film is provided, for example, for EMC (Electromagnetic Compatibility) measures and is electrically connected to the ground.

[0005] One aspect of the present disclosure provides a technique for suppressing a short circuit between a conductor and a heating film that constitute a sensor cover.

Means for Solving the Problems

[0006] A cover for a sensor according to one aspect of the present disclosure is provided at an opening of a housing that houses the sensor. The sensor cover includes a conductor and a heating film in a desired order from the outside of the housing toward the inside of the housing. The conductor is a conductive oxide. The conductor and the heating film are insulated from each other. The conductor is electrically connected to ground. The shortest distance between the conductor and the heating film is 2.0 μm or more.

Advantages of the Invention

[0007] According to one aspect of the present disclosure, since the shortest distance between the conductor and the heating film, which are insulated from each other, is 2.0 μm or more, it is possible to suppress a short circuit between the conductor and the heating film.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and the description thereof may be omitted. In the specification, "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value.

[0010] First, referring to FIG. 1, a sensor module 1 according to an embodiment will be described. The sensor module 1 includes a sensor cover 2, a housing 3, and a sensor 5. The housing 3 houses the sensor 5. The housing 3 may function as a frame ground and is formed of a conductive material such as metal in that case. The sensor 5 is not particularly limited, but is, for example, an in-vehicle sensor. The in-vehicle sensor is, for example, a LiDAR (Light Detection and Ranging) sensor.

[0011] The LiDAR sensor irradiates an object with near-infrared light and receives the near-infrared light reflected by the object to detect the distance to the object and the direction of the object. Although not shown, the LiDAR sensor includes, for example, a laser light source, an irradiation optical system that irradiates the object with near-infrared light from the laser light source, a light receiving optical system that guides the near-infrared light reflected by the object to a light receiver, and the light receiver. Note that the in-vehicle sensor is not limited to the LiDAR sensor and may be an imaging sensor such as a CCD image sensor or a CMOS image sensor.

[0012] The light detected by the sensor 5 is preferably near-infrared light. Near-infrared light is an electromagnetic wave having a wavelength of 700 nm to 2500 nm. Currently, near-infrared light having a wavelength of 1530 nm to 1570 nm is being studied as the near-infrared light for the LiDAR sensor. Note that the light detected by the sensor 5 is near-infrared light in the present embodiment, but is not limited to near-infrared light and may be, for example, visible light or ultraviolet light. The sensor 5 is not limited to the in-vehicle sensor and may be any optical sensor.

[0013] Next, referring to FIGS. 1 and 2, a sensor cover 2 according to an embodiment will be described. The sensor cover 2 is provided at the opening of the housing 3 to prevent snow, rain, dust, etc. from entering the inside of the housing 3 and protect the sensor 5. The sensor cover 2 is, for example, an infrared pass filter that transmits near-infrared light and shields visible light. When the light detected by the sensor 5 is near-infrared light, the sensitivity of the sensor 5 is good. Also, by shielding visible light, the sensor 5 can be made invisible from the outside of the housing 3.

[0014] The cover 2 for the sensor includes a base material 21, a conductive film 22, a dielectric multilayer film 23, and a heating film 24 in a desired order from the outside of the housing 3 toward the inside of the housing 3. For example, the cover 2 for the sensor includes the base material 21, the conductive film 22, the dielectric multilayer film 23, and the heating film 24 in this order from the outside of the housing 3 toward the inside of the housing 3.

[0015] The base material 21 is for forming the conductive film 22 and the dielectric multilayer film 23. The base material 21 is, for example, plate-shaped. The thickness of the base material 21 is preferably 0.1 mm or more and 5 mm or less, more preferably 2 mm to 4 mm, from the viewpoints of (A) reducing warpage generated when forming the conductive film 22 and the dielectric multilayer film 23, etc., (B) thinning, and (C) crack suppression. Note that the shape of the base material 21 is not particularly limited.

[0016] The material of the base material 21 may be an organic material or an inorganic material as long as it is a material that transmits the light detected by the sensor 5, and is not particularly limited. The base material 21 may be a composite of a plurality of different materials. The base material 21 may have a single-layer structure or a multilayer structure. As the inorganic material of the base material 21, glass or a crystal material is preferably used.

[0017] The glass is soda-lime glass, borosilicate glass, alkali-free glass, fused silica glass, or aluminosilicate glass. The glass may be chemically strengthened glass. Chemically strengthened glass is formed by forming a compressive stress layer on the glass surface by ion exchange at a temperature below the glass transition point. The compressive stress layer is formed by exchanging alkali metal ions with a small ionic radius contained in the glass for alkali ions with a larger ionic radius.

[0018] The crystal material may be a birefringent crystal, for example, silicon dioxide, lithium niobate, or sapphire.

[0019] Note that the base material 21 may be formed of a conductive material and may have the function of the conductive film 22 described later.

[0020] The conductive film 22 is provided, for example, for electromagnetic compatibility (EMC) measures and is electrically connected to the ground. The ground is, for example, the housing 3, and the housing 3 and the conductive film 22 are adhered with a conductive adhesive 29. The conductive adhesive 29 may be a common one. The conductive adhesive 29 is provided, for example, at the periphery of the conductive film 22. When the sensor 5 is an in-vehicle sensor, the vehicle body may be used as the ground.

[0021] The conductive film 22 may be made of any material that can transmit the light detected by the sensor 5 and is not particularly limited. The conductive film 22 may be a composite of a plurality of different materials. The conductive film 22 may have a single-layer structure or a multi-layer structure. The conductive film 22 is preferably formed of a conductive oxide. The conductive oxide is, for example, indium tin oxide (ITO), indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), or fluorine-doped tin oxide (FTO).

[0022] The dielectric multilayer film 23 is, for example, an infrared pass filter that transmits near-infrared light and shields visible light. The dielectric multilayer film 23 may also serve as an antireflection film to prevent reflection of near-infrared light in order to improve the transmittance of near-infrared light. The antireflection film is in contact with air and prevents reflection of near-infrared light at the interface between the air and the sensor cover 2. The dielectric multilayer film 23 prevents reflection of light propagating from the inside to the outside of the housing 3, for example.

[0023] The dielectric multilayer film 23 includes a high refractive index film and a low refractive index film alternately, and the reflectance can be increased or decreased by utilizing the interference effect of light. The higher the reflectance, the lower the transmittance. The transmittance also depends on the attenuation coefficient. The attenuation coefficient is determined by the type of material. The larger the attenuation coefficient, the higher the absorption rate and the lower the transmittance.

[0024] Either the high refractive index film or the low refractive index film (preferably the high refractive index film) preferably satisfies the following (1) and (2). (1) The attenuation coefficient k at a wavelength of 600 nm 600 is 0.12 or more. (2) The minimum value k of the attenuation coefficient in the wavelength range of 1530 nm to 1570 nm 1530-1570MIN is 0.01 or less.

[0025] (1) Since k 600 is 0.12 or more, red light near 600 nm can be blocked by absorption. An optical filter with a reflection color less likely to exhibit red can be obtained compared to the case where red light near 600 nm is blocked by reflection. k 600 is preferably 0.18 or more and is preferably 1.00 or less. As a material where k 600 is within the above range, for example, amorphous silicon with a hydrogen doping amount of 20 sccm or less can be mentioned.

[0026] (2) Since k 1530-1570MIN is 0.01 or less, near-infrared light near a wavelength of 1530 nm to 1570 nm can be sufficiently transmitted. k 1530-1570MIN is preferably 0.002 or less.

[0027] Either the high refractive index film or the low refractive index film (preferably the high refractive index film) preferably further satisfies the following optical property (3). (3) The minimum value k of the attenuation coefficient in the wavelength range of 800 nm to 1000 nm 800-1000MIN is 0.0005 or more.

[0028] (3) Since k 800-1000MIN is 0.0005 or more, the value of k 600 is moderately increased, and red light near 600 nm can be blocked by absorption. k 800-1000MIN is preferably 0.001 or more. k 800-1000MIN is preferably 0.1 or less.

[0029] From the viewpoint of design freedom, the film satisfying the above (1) and (2) is preferably a high refractive index film. In this case, the attenuation coefficient k of the low refractive index film 600is preferably 0.015 or more, and k 1530-1570MIN is preferably 0.

[0030] The refractive index of the high refractive index film is preferably 3.5 or more, more preferably 4.0 or more. The material of the high refractive index film is, for example, silicon, Ta2O5, TiO2, Nb2O5, or SiN. Among these, from the viewpoints of the above (1) and (2), silicon is preferable, particularly amorphous silicon is preferable, and amorphous silicon with a hydrogen doping amount of 20 sccm or less is more preferable.

[0031] The refractive index of the low refractive index film is preferably 2.5 or less, more preferably 1.5 or less. Examples of the material of the low refractive index film include SiO2, SiO x N y , Ta2O5, TiO2, SiO, etc. Among these, from the viewpoint of productivity, SiO2 is preferable.

[0032] The total number of stacked layers of the high refractive index film and the low refractive index film is preferably 10 or more, more preferably 15 or more, and even more preferably 20 or more so as to efficiently block visible light. However, when the total number of stacked layers increases, warping or the like may occur, or the film thickness may increase. Therefore, the total number of stacked layers is preferably 70 or less, more preferably 60 or less, and even more preferably 50 or less.

[0033] From the viewpoint of productivity, the film thickness of the dielectric multilayer film 23 is preferably 1.5 μm or less, more preferably 2.0 μm or less.

[0034] The dielectric multilayer film 23 preferably further satisfies the following optical characteristics. The maximum value T of the transmittance in the wavelength range of 400 nm to 680 nm is 6% or less and the maximum value R of the reflectance in the wavelength range of 400 nm to 680 nm is 10% or less so that both the transmitted color and the reflected color of visible light become black. The minimum value of the transmittance in the wavelength range of 1530 nm to 1570 nm is T so as to increase the sensitivity of the sensor 5 400-680MAX is 400-680MAX and the maximum value R of the reflectance in the wavelength range of 400 nm to 680 nm is 10% or less. The minimum value of the transmittance in the wavelength range of 1530 nm to 1570 nm is T so as to increase the sensitivity of the sensor 5 1530-1570MINis 90% or more.

[0035] The method of forming the dielectric multilayer film 23 may be either a dry method or a wet method. Examples of the dry film-forming method include a CVD method, a sputtering method, or a vacuum evaporation method. Examples of the wet film-forming method include a spray method or a dip method.

[0036] Although not shown, a dielectric multilayer film different from the dielectric multilayer film 23 may be provided. The other dielectric multilayer film has optical characteristics different from those of the dielectric multilayer film 23. For example, while the dielectric multilayer film 23 transmits near-infrared rays and shields visible light, the other dielectric multilayer film may transmit both near-infrared rays and visible light.

[0037] In this embodiment, the dielectric multilayer film 23 also serves as an antireflection film for preventing reflection of near-infrared rays, but it does not have to serve as an antireflection film. In the latter case, an antireflection film may be provided on the dielectric multilayer film 23. The antireflection film may have, for example, a moth-eye structure that continuously changes the effective refractive index from air toward the dielectric multilayer film 23, or may have a refractive index intermediate between air and the dielectric multilayer film 23.

[0038] In this embodiment, the dielectric multilayer film 23 transmits near-infrared rays, but it only needs to transmit light of the wavelength detected by the sensor 5, and may transmit visible light or the like. In this embodiment, the dielectric multilayer film 23 shields visible light, but it does not have to shield visible light.

[0039] The heating film 24 heats the outer surface of the sensor cover 2 by generating heat, thereby preventing snow accumulation, ice formation, or dew condensation on the outer surface. The heating film 24 is arranged so as not to interfere with the light irradiated from the sensor 5 and the light detected by the sensor 5, and is formed, for example, in a linear shape. The heating film 24 is electrically connected to the power supply 6. The power supply 6 supplies a current to the heating film 24 by applying a voltage to the heating film 24. The heating film 24 generates heat by Joule heat.

[0040] The heating film 24 is preferably a metal film. The metal film is formed of a pure metal or an alloy containing at least one element selected from the group consisting of, for example, silver (Ag), gold (Au), copper (Cu), aluminum (Al), tin (Sn), iron (Fe), nickel (Ni), chromium (Cr), and tungsten (W). The heating film 24 may be a carbon film.

[0041] The heating film 24 may be formed by baking a conductive paste, or may be formed by processing a metal foil or a metal wire. The heating film 24 is provided, for example, inside the housing 3 rather than the base material 21. The base material 21 protects the heating film 24 and suppresses, for example, disconnection of the heating film 24. The heating film 24 is provided, for example, on a part of the surface of the dielectric multilayer film 23 in contact with air.

[0042] The sensor cover 2 may include a second dielectric multilayer film 25 on the side opposite to the dielectric multilayer film 23 with respect to the base material 21. The sensor cover 2 includes, in this order from the outside of the housing 3 toward the inside of the housing 3, the second dielectric multilayer film 25, the base material 21, the conductive film 22, the dielectric multilayer film 23, and the heating film 24. Note that the second dielectric multilayer film 25 may be omitted, and the dielectric multilayer film 23 may be provided at the position of the second dielectric multilayer film 25.

[0043] Similar to the dielectric multilayer film 23, the second dielectric multilayer film 25 is, for example, an infrared pass filter that transmits near-infrared rays and shields visible light. The second dielectric multilayer film 25 may also serve as an antireflection film that prevents reflection of near-infrared rays in order to improve the transmittance of near-infrared rays. The second dielectric multilayer film 25 prevents reflection of light propagating from the outside of the housing 3 toward the inside of the housing 3.

[0044] Since the configuration of the second dielectric multilayer film 25 is the same as that of the dielectric multilayer film 23, the description thereof is omitted.

[0045] Incidentally, the conductive film 22 and the heating film 24 are insulated to prevent leakage of electricity from the heating film 24 to the conductive film 22. Current can be efficiently supplied to the heating film 24, and the heating film 24 can efficiently generate heat. Further, when the conductive film 22 is electrically connected to the ground, the potential of the conductive film 22 can be maintained at the reference potential. Unlike the heating film 24, the conductive film 22 does not apply a voltage and does not generate heat. The conductive film 22 is maintained at an equipotential as a whole, unlike the heating film 24.

[0046] The shortest distance L between the conductive film 22 and the heating film 24 min is 2.0 μm or more. L min If L is 2.0 μm or more, the electrical resistance between the heating film 24 and the conductive film 22 is high, and leakage of electricity from the heating film 24 to the conductive film 22 can be suppressed. L min is preferably 5 μm or more. L min From the viewpoint of productivity, it is 0.3 mm or less.

[0047] The current value I when a voltage of 12 V is applied to the shortest path between the conductive film 22 and the heating film 24 12V is preferably 1.0 mA (1.0×10 -3 A) or less. The current value I 12V If the current value I is 1.0 mA or less, the electrical resistance between the heating film 24 and the conductive film 22 is high, and leakage of electricity from the heating film 24 to the conductive film 22 can be suppressed. The current value I 12V is preferably 0.1 mA or less. The current value I 12V may be 0 mA.

[0048] The resistance value of the shortest path between the conductive film 22 and the heating film 24 is preferably 1.2×10 4 Ω or more, more preferably 1.2×10 5 Ω or more.

[0049] Note that the shortest path between the conductive film 22 and the heating film 24 is parallel to the thickness direction (the left - right direction in FIG. 1) of the conductive film 22 in the present embodiment, but may be inclined as described later. The thickness direction of the conductive film 22 is the lamination direction of the conductive film 22 and the heating film 24.

[0050] Between the conductive film 22 and the heating film 24, for example, a dielectric multilayer film 23 is provided. The dielectric multilayer film 23 is an insulating film. From the viewpoint of productivity, the film thickness of the dielectric multilayer film 23 is preferably 1.5 μm or less, more preferably 1.0 μm or less. Only the thickness of the dielectric multilayer film 23 makes L min It is difficult to make it 2.0 μm or more.

[0051] Therefore, the sensor cover 2 may include an insulating film 26 between the dielectric multilayer film 23 and the heating film 24. The film thickness of the insulating film 26 is preferably 0.5 μm or more, more preferably 1.0 μm or more. The total film thickness of the dielectric multilayer film 23 and the insulating film 26 may be 2.0 μm or more.

[0052] The larger the film thickness of the insulating film 26, the more leakage current from the heating film 24 to the conductive film 22 can be suppressed. The film thickness of the insulating film 26 is preferably larger than the film thickness of the dielectric multilayer film 23. From the viewpoint of the productivity of the sensor cover 2, the film thickness of the insulating film 26 is preferably 0.3 mm or less.

[0053] The insulating film 26 may be provided in a strip shape along the linear heating film 24 so as not to interfere with the light detected by the sensor 5, for example, as shown in FIG. 2. The insulating film 26 may be ring-shaped or C-shaped. The width of the insulating film 26 may be wider than the width of the heating film 24, and the heating film 24 is disposed on the insulating film 26 so as not to protrude from the insulating film 26, for example.

[0054] Electrodes 27 are provided at both ends of the heating film 24. The pair of electrodes 27 electrically connect the heating film 24 to the power supply 6. The pair of electrodes 27 is also disposed on the insulating film 26 so as not to protrude from the insulating film 26, similar to the heating film 24.

[0055] The material of the insulating film 26 may be an organic material or an inorganic material, and is not particularly limited. The insulating film 26 may be a composite of a plurality of different materials. The insulating film 26 may have a single-layer structure or a multi-layer structure. The material of the insulating film 26 may be either an organic material or an inorganic material, or a mixture thereof. Examples of the organic material include epoxy resin, phenolic resin, silicone resin, urethane resin, polyester resin, or polyimide resin. The inorganic material may be any of glass, ceramic, or silicon. Examples of the glass include soda-lime glass, alumina silicate glass, or borosilicate glass. Examples of the ceramic include silicon dioxide (SiO2) or titanium dioxide (TiO2). When the heating film 24 is a film heater, the material of the insulating film 26 is preferably an organic material, and particularly preferably polyethylene terephthalate resin (PET resin), polycarbonate resin, acrylic resin, polyethylene resin, polyvinyl chloride resin (PVC resin), or polyimide resin.

[0056] In addition, the second dielectric multilayer film 25 may be absent, and a dielectric multilayer film 23 may be provided at the position of the second dielectric multilayer film 25, and only the insulating film 26 may exist between the conductive film 22 and the heating film 24. In this case, if the thickness of the insulating film 26 is 2.0 μm or more, L min is 2.0 μm or more, so that leakage from the heating film 24 to the conductive film 22 can be suppressed.

[0057] Next, with reference to FIG. 3, the sensor cover 2 according to the first modified example will be described. Hereinafter, mainly the differences will be described. As shown in FIG. 3, the sensor cover 2 may include a second dielectric multilayer film 25, a conductive film 22, a base material 21, a dielectric multilayer film 23, and a heating film 24 in this order from the outside of the housing 3 toward the inside of the housing 3. Note that the second dielectric multilayer film 25 may be absent.

[0058] The base material 21 has insulating properties and insulates the conductive film 22 and the heating film 24. The thickness of the base material 21 is greater than the thickness of the dielectric multilayer film 23. Therefore, by disposing the insulating base material 21 between the conductive film 22 and the heating film 24, the shortest distance L between the conductive film 22 and the heating film 24min can be made long enough to suppress leakage current from the heating film 24 to the conductive film 22.

[0059] Note that there is no insulating film 26 shown in Fig. 3 between the dielectric multilayer film 23 and the heating film 24, but there may be an insulating film 26. Also, the second dielectric multilayer film 25 may be absent, and the dielectric multilayer film 23 may be provided at the position of the second dielectric multilayer film 25. Only the insulating base material 21 may exist between the conductive film 22 and the heating film 24. If the thickness of the base material 21 is 2.0 μm or more, since L min is 2.0 μm or more, leakage current from the heating film 24 to the conductive film 22 can be suppressed.

[0060] Next, with reference to Figs. 4 and 5, the sensor cover 2 according to the second modification will be described. Below, mainly the differences will be described. As shown in Fig. 4, the sensor cover 2 may include, in this order from the outside to the inside of the housing 3, a second dielectric multilayer film 25, a base material 21, a conductive film 22, a dielectric multilayer film 23, and a heating film 24. Note that the second dielectric multilayer film 25 may be absent.

[0061] As shown in Fig. 4, the conductive film 22 has an opening pattern 22a. The opening pattern 22a may be filled with an insulating material instead of air. As shown in Fig. 5, when viewed from the thickness direction of the conductive film 22, the heating film 24 is disposed inside the contour line (e.g., the broken line in Fig. 5) of the opening pattern 22a.

[0062] As shown in Fig. 4, the opening pattern 22a inclines the shortest path between the conductive film 22 and the heating film 24 with respect to the thickness direction (the left - right direction in Fig. 4) of the conductive film 22. Thereby, the shortest distance L min can be made long, and leakage current from the heating film 24 to the conductive film 22 can be suppressed.

[0063] As shown in Fig. 5, when viewed in the thickness direction of the conductive film 22, the opening pattern 22a may be provided in a strip shape along the linear heating film 24. The opening pattern 22a is formed such that the center of the conductive film 22 and the periphery of the conductive film 22 are electrically connected, and is formed, for example, in a C shape. Note that the shape of the opening pattern 22a is not particularly limited. If both ends of the strip-shaped opening pattern 22a are not connected and are separated, the center of the conductive film 22 and the periphery of the conductive film 22 are electrically connected, and the center of the conductive film 22 is also electrically connected to the housing 3.

[0064] Note that there is no insulating film 26 between the dielectric multilayer film 23 and the heating film 24 shown in Fig. 4, but there may be an insulating film 26. When there is an insulating film 26, the second dielectric multilayer film 25 may be absent, and the dielectric multilayer film 23 may be provided at the position of the second dielectric multilayer film 25. That is, only the insulating film 26 may exist between the conductive film 22 and the heating film 24.

[0065] Also, as shown in Fig. 4, the base material 21, the conductive film 22, the dielectric multilayer film 23, and the heating film 24 are arranged in this order. However, similar to the first modification example, the conductive film 22, the base material 21, the dielectric multilayer film 23, and the heating film 24 may be arranged in this order. In the latter case, that is, when the base material 21 exists between the conductive film 22 and the heating film 24 and the base material 21 has insulating properties, the second dielectric multilayer film 25 may be absent, and the dielectric multilayer film 23 may be provided at the position of the second dielectric multilayer film 25. Only the insulating base material 21 may exist between the conductive film 22 and the heating film 24.

Example

[0066] Hereinafter, the experimental data will be described. Examples 1 to 5 and 7 below are examples, and Example 6 below is a comparative example.

[0067] In Example 1, as shown in FIG. 6, a sensor cover 2 including a base material 21, a conductive film 22, a dielectric multilayer film 23, an insulating film 26, and a heating film 24 in this order was fabricated. The base material 21 was a glass substrate, the conductive film 22 was an ITO film, and the dielectric multilayer film 23 was a multilayer film having an aSi film (amorphous silicon film) and a SiO2 film alternately. The insulating film 26 was a mixture containing a resin and silicon dioxide (SiO2). Specifically, an insulating paste (product name: Ohm Coat 1057K) manufactured by Namics was applied onto the dielectric multilayer film 23 and fired at 200°C for 30 minutes to form it. The film thickness of the insulating film 26 was 1 μm. The heating film 24 was an Ag film. Specifically, an Ag paste was applied onto the insulating film 26 and fired at 150°C for 30 minutes to form it. The film thickness of the heating film 24 was 20 μm. As shown in FIG. 6, for the leakage test, a DC voltage of 12 V was applied between the conductive film 22 and the heating film 24, and the presence or absence of current was measured with an ammeter 7 to examine the presence or absence of leakage. As a result of the leakage test, no leakage was observed.

[0068] In Example 2, a sensor cover 2 was fabricated in the same manner as in Example 1 except that the film thickness of the insulating film 26 was changed to 10 μm. As a result of the leakage test, no leakage was observed.

[0069] In Example 3, a sensor cover 2 was fabricated in the same manner as in Example 1 except that the film thickness of the insulating film 26 was changed to 20 μm. As a result of the leakage test, no leakage was observed.

[0070] In Example 4, a sensor cover 2 was fabricated in the same manner as in Example 1 except that the film thickness of the insulating film 26 was changed to 40 μm. As a result of the leakage test, no leakage was observed.

[0071] In Example 5, a sensor cover 2 was fabricated in the same manner as in Example 1, except that the material of the insulating film 26 was changed and the film thickness of the insulating film 26 was changed to 20 μm. In Example 5, the insulating film 26 is a mixture containing bismuth trioxide (Bi2O3), zinc oxide (ZnO), and boron oxide (B2O3). Specifically, an insulating paste (product name: US6F-TAX9B) manufactured by AGC Inc. was applied onto the dielectric multilayer film 23 and formed by baking at 450 °C for 10 minutes. As a result of the leakage test, no leakage was observed.

[0072] In Example 6, a sensor cover 2 was fabricated in the same manner as in Example 1, except that the heating film 24 was formed directly on the dielectric multilayer film 23 without forming the insulating film 26. As a result of the leakage test, leakage was observed.

[0073] In Example 7, a sensor cover 2 was fabricated in the same manner as in Example 6, except that the total number of stacked layers of the aSi film and the SiO2 film constituting the dielectric multilayer film 23 was increased and the film thickness of the dielectric multilayer film 23 was changed to 3.3 μm. As a result of the leakage test, no leakage was observed.

[0074] The test results of Examples 1 to 7 are shown in Table 1.

[0075]

Table 1

[0076] As is clear from Table 1, in Examples 1 to 5 and Example 7, the shortest distance L min between the conductive film 22 and the heating film 24 is 2.0 μm or more, and the current value I 12V when a voltage of 12 V is applied to the shortest path between the conductive film 22 and the heating film 24 is 1 mA or less, and no leakage was observed.

[0077] On the other hand, in Example 8, since the shortest distance L min between the conductive film 22 and the heating film 24 was less than 2.0 μm, the current value I 12VIt exceeded 1 mA, and leakage current was observed.

[0078] As described above, the cover for a sensor and the sensor module according to the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments and the like. Within the scope described in the claims, various changes, modifications, substitutions, additions, deletions, and combinations are possible. Naturally, those also belong to the technical scope of the present disclosure.

[0079] Regarding the above-described embodiments and the like, the following supplementary notes are disclosed. [Supplementary Note 1] A cover for a sensor provided at an opening of a housing that houses the sensor, comprising a conductor, a dielectric multilayer film, and a heating film in a desired order from the outside of the housing toward the inside of the housing, wherein the conductor and the heating film are insulated from each other, and a cover for a sensor, wherein a shortest distance between the conductor and the heating film is 2.0 μm or more. [Supplementary Note 2] The cover for a sensor according to Supplementary Note 1, wherein the conductor is electrically connected to the ground. [Supplementary Note 3] The cover for a sensor according to Supplementary Note 2, wherein the conductor is electrically connected to the housing as the ground. [Supplementary Note 4] The cover for a sensor according to any one of Supplementary Notes 1 to 3, wherein the heating film is electrically connected to a power source. [Supplementary Note 5] The cover for a sensor according to any one of Supplementary Notes 1 to 4, wherein the heating film is formed linearly. [Supplementary Note 6] The cover for a sensor according to any one of Supplementary Notes 1 to 5, wherein a current value when a voltage of 12 V is applied to a shortest path between the conductor and the heating film is 1 mA or less. [Supplementary Note 7] Comprising the conductor, the dielectric multilayer film, and the heating film in this order from the outside of the housing toward the inside of the housing, The sensor cover according to any one of Appendices 1 to 6, comprising an insulating film between the dielectric multilayer film and the heating film. [Appendix 8] From the outside to the inside of the housing, the conductor, the base material, the dielectric multilayer film, and the heating film are provided in this order. The sensor cover according to any one of Appendices 1 to 6, wherein the base material has insulation properties. [Appendix 9] From the outside to the inside of the housing, the conductor, the dielectric multilayer film, and the heating film are provided in this order. The conductor is a film having an opening pattern, and the heating film is disposed inside the contour line of the opening pattern when viewed from the thickness direction of the conductor. The sensor cover according to any one of Appendices 1 to 6. [Appendix 10] The sensor cover according to any one of Appendices 1 to 9, comprising a second dielectric multilayer film on the side opposite to the dielectric multilayer film with respect to the conductor. [Appendix 11] The sensor cover according to any one of Appendices 1 to 10, which is an infrared pass filter that transmits near-infrared rays and blocks visible light. [Appendix 12] The sensor cover according to any one of Appendices 1 to 11, wherein the sensor is a LiDAR (Light Detection and Ranging) sensor. [Appendix 13] A sensor module comprising the sensor cover according to any one of Appendices 1 to 12, the housing, and the sensor.

[0080] This application claims priority based on Japanese Patent Application No. 2021-173364 filed with the Japan Patent Office on October 22, 2021, and incorporates the entire contents of Japanese Patent Application No. 2021-173364 into this application.

Explanation of Reference Numerals

[0081] 2 Sensor cover 21 Base material 22 Conductive film (conductor) 23 Dielectric multilayer film 24 Heating film L min Shortest distance

Claims

1. A sensor cover provided at an opening of a housing that houses a sensor, A conductor and a heating film are provided in a desired order from the outside of the housing toward the inside of the housing, the conductor is a conductive oxide including at least one of ITO, IZO, IGZO, AZO, GZO, and FTO, The conductor and the heating film are insulated from each other, The conductor is electrically connected to ground; A sensor cover, wherein the shortest distance between the conductor and the heating film is 2.0 μm or more.

2. The housing is made of a conductive material, The sensor cover according to claim 1 , wherein the conductor is electrically connected to the housing that serves as the ground.

3. The sensor cover according to claim 1 , wherein the heat generating film is electrically connected to a power source.

4. The sensor cover according to any one of claims 1 to 3, wherein the heat generating film is formed in a linear shape.

5. The sensor cover according to any one of claims 1 to 3, wherein a current value when a voltage of 12 V is applied to the shortest path between the conductor and the heating film is 1 mA or less.

6. the conductor, the dielectric multilayer film, and the heat generating film are provided in this order from the outside of the housing toward the inside of the housing, The sensor cover according to any one of claims 1 to 3, further comprising an insulating film between the dielectric multilayer film and the heat generating film.

7. the conductor, the dielectric multilayer film, and the heat generating film are provided in this order from the outside of the housing toward the inside of the housing, an insulating film is provided between the dielectric multilayer film and the heat generating film; The sensor cover according to claim 4 , wherein the insulating film is provided in a strip shape along the linear heating film.

8. the conductor, the base material, the dielectric multilayer film, and the heat generating film are provided in this order from the outside of the housing toward the inside of the housing, The sensor cover according to any one of claims 1 to 3, wherein the base material has insulating properties.

9. The electric conductor and the heating film are provided in this order from the outside of the housing toward the inside of the housing, The sensor cover of any one of claims 1 to 3, wherein the conductor is a film having an opening pattern, and the heating film is positioned inside the contour line of the opening pattern when viewed in the thickness direction of the conductor.

10. the conductor, the dielectric multilayer film, and the heat generating film are provided in this order from the outside of the housing toward the inside of the housing, 4. The sensor cover according to claim 1, further comprising a second dielectric multilayer film on the opposite side of the dielectric multilayer film with respect to the conductor.

11. The sensor cover according to any one of claims 1 to 3, wherein the sensor cover is an infrared pass filter that transmits near-infrared rays and blocks visible light.

12. The sensor cover according to any one of claims 1 to 3, wherein the sensor is a LiDAR (Light Detection and Ranging) sensor.

13. A sensor module comprising: the sensor cover according to any one of claims 1 to 3; the housing; and the sensor.

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