Optical sensor cover and optical sensor

Abstract

This optical sensor cover comprises a light transmissive substrate and a linear heat generation body that is provided on the substrate. The heat generation body is formed from a plurality of wire segments (331) demarcated using a plurality of imaginary square lattices (35) of which one side is 10 mm and which are arranged in the in-plane direction of the substrate. The plurality of wire segments (331) include first wire segments (331F1-331F16) and second wire segments (331S1-331S2, or 331S3). The average resistance value Rn / Ln of 50% or more first wire segments from among all of the first wire segments is lower than the average resistance value Rm / Lm of the second wire segments when Ln is the length of the first wire segments as measured at a coarse graining level of 10 mm, Lm is the length of the second wire segments as measured at a coarse graining level of 10 mm, Rn is the resistance value of the first wire segments, and Rm is the resistance value of the second wire segments.

Description

Optical sensor cover and optical sensor

[0001] The present disclosure relates to a cover for an optical sensor and an optical sensor.

[0002] There is known an optical sensor such as a distance measuring sensor that measures the distance to an object and includes optical elements such as a light projecting unit that projects near-infrared light onto an object and a light receiving unit that receives light reflected by the object. The optical sensor includes an optical sensor cover that protects the internal optical elements. Patent Document 1 discloses a heating system that removes condensation that has adhered to the optical sensor cover (see, for example, Patent Document 1).

[0003] U.S. Pat. No. 1,058,8178

[0004] The heating system disclosed in Patent Document 1 heats the surface of the optical sensor cover by passing a current through a transparent conductive film extending between a pair of bus bar electrodes provided on the optical sensor cover. However, the transparent conductive film covers the light-transmitting area of ​​the optical sensor cover and absorbs near-infrared light. This reduces the light transmittance of the optical sensor cover.

[0005] The present disclosure provides an optical sensor cover and an optical sensor that suppress a decrease in light transmittance.

[0006] The optical sensor cover of a first aspect comprises: a substrate having optical transparency; and a linear heating element provided on the substrate, wherein the heating element is composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of divided wirings including a first divided wiring and a second divided wiring, wherein the first divided wiring is a divided wiring in which L'n is an actual length of the first divided wiring and Ln is a length of the first divided wiring measured at a roughness of 10 mm, L'n / Ln is less than 1.2, and the first divided wiring includes a position at a distance of 20 mm or less from an edge of the substrate, The second divided wiring is a divided wiring among the divided wirings excluding the first divided wiring, in which L'm is the actual length of the second divided wiring and Lm is the length of the second divided wiring measured at a roughness of 10 mm, and L'm / Lm is less than 1.2 and does not include a position 20 mm or less from the edge of the substrate, or, when there is no divided wiring among the divided wirings excluding the first divided wiring that does not include a position 20 mm or less from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position among the divided wirings excluding the first divided wiring that is the farthest from the edge of the substrate, when a resistance value of the first divided wiring is Rn, an average resistance value of the first divided wiring is Rn / Ln, a resistance value of the second divided wiring is Rm, and an average resistance value of the second divided wiring is Rm / Lm, The average resistance value Rn / Ln of 50% or more of all the first divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

[0007] The optical sensor cover of the second aspect comprises: a substrate having optical transparency; and a linear heating element provided on the substrate, wherein the heating element is composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of divided wirings including a third divided wiring and a second divided wiring, wherein the third divided wiring is a divided wiring in which the actual length of the third divided wiring is L'k and the length of the third divided wiring measured at a coarseness of 10 mm is Lk, and L'k / Lk is 1.2 or more, The second divided wiring is a divided wiring among the divided wirings excluding the third divided wiring, in which the actual length of the second divided wiring is L'm and the length of the second divided wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position 20 mm or less from the edge of the substrate, or, when there is no divided wiring among the divided wirings excluding the third divided wiring that does not include a position 20 mm or less from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position among the divided wirings excluding the third divided wiring that is the farthest from the edge of the substrate, when a resistance value of the third divided wiring is Rk, an average resistance value of the third divided wiring is Rk / L'k, a resistance value of the second divided wiring is Rm, and an average resistance value of the second divided wiring is Rm / Lm, The average resistance value Rk / L'k of 50% or more of all the third divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

[0008] The optical sensor cover of the third aspect may be the same as the first aspect, wherein the first divided wiring has at least one curved portion.

[0009] The optical sensor cover of a fourth aspect may be the same as the second aspect, in which the third divided wiring has at least one bent portion.

[0010] The optical sensor cover of the fifth aspect may be the first or third aspect, wherein the average resistance value Rn / Ln of the first divided wiring is 0.3 to 0.95 times the average resistance value Rm / Lm of the second divided wiring.

[0011] The sixth aspect of the optical sensor cover may be such that, in the second or fourth aspect, the average resistance value Rk / L'k of the third divided wiring is 0.3 to 0.95 times the average resistance value Rm / L'm of the second divided wiring.

[0012] The seventh aspect of the optical sensor cover is any one of the first, third, or fifth aspects, wherein the first divided wiring may include an area having a line width wider than the average line width of the heating element.

[0013] The optical sensor cover of the eighth aspect is any one of the second, fourth, or sixth aspects, wherein the third divided wiring may include an area having a line width wider than the average line width of the heating element.

[0014] The optical sensor cover of a ninth aspect is any one of the first to eighth aspects, wherein the heating element may include at least one of gold, silver, copper, tin, aluminum, and an alloy using any of these.

[0015] An optical sensor of a tenth aspect comprises: a housing; an optical element housed in the housing; and an optical sensor cover attached to the housing so as to cover the optical element, wherein the optical sensor cover comprises: a light-transmitting substrate; and a linear heating element provided on the substrate, wherein the heating element is composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, wherein the plurality of divided wirings include a first divided wiring and a second divided wiring, wherein the first divided wiring is a divided wiring having an actual length L'n and a length of the first divided wiring measured at a coarseness of 10 mm, L'n / Ln being less than 1.2, and including a position at a distance of 20 mm or less from an edge of the substrate, The second divided wiring is a divided wiring among the divided wirings excluding the first divided wiring, in which L'm is the actual length of the second divided wiring and Lm is the length of the second divided wiring measured at a roughness of 10 mm, and L'm / Lm is less than 1.2 and does not include a position 20 mm or less from the edge of the substrate, or, when there is no divided wiring among the divided wirings excluding the first divided wiring that does not include a position 20 mm or less from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position among the divided wirings excluding the first divided wiring that is the farthest from the edge of the substrate, when a resistance value of the first divided wiring is Rn, an average resistance value of the first divided wiring is Rn / Ln, a resistance value of the second divided wiring is Rm, and an average resistance value of the second divided wiring is Rm / Lm, The average resistance value Rn / Ln of 50% or more of all the first divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

[0016] An optical sensor of an eleventh aspect comprises: a housing; an optical element housed in the housing; and an optical sensor cover attached to the housing so as to cover the optical element, wherein the optical sensor cover comprises: a light-transmitting substrate; and a linear heating element provided on the substrate, wherein the heating element is composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, wherein the plurality of divided wirings include a third divided wiring and a second divided wiring, wherein the third divided wiring is a divided wiring such that L'k is an actual length of the third divided wiring and Lk is a length of the third divided wiring measured at a coarseness of 10 mm, and L'k / Lk is 1.2 or more, The second divided wiring is a divided wiring among the divided wirings excluding the third divided wiring, in which the actual length of the second divided wiring is L'm and the length of the second divided wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position 20 mm or less from the edge of the substrate, or, when there is no divided wiring among the divided wirings excluding the third divided wiring that does not include a position 20 mm or less from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position among the divided wirings excluding the third divided wiring that is the farthest from the edge of the substrate, when a resistance value of the third divided wiring is Rk, an average resistance value of the third divided wiring is Rk / L'k, a resistance value of the second divided wiring is Rm, and an average resistance value of the second divided wiring is Rm / Lm, The average resistance value Rk / L'k of 50% or more of all the third divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

[0017] A twelfth aspect of the optical sensor is the tenth or eleventh aspect, wherein the housing is made of resin or metal, and when the housing is made of metal, a heat insulating material may be provided between the housing and the substrate.

[0018] The optical sensor of the thirteenth aspect is a distance measuring sensor in any one of the tenth to twelfth aspects, and the optical element may include a light-projecting unit and a light-receiving unit that receives reflected light that is light projected from the light-projecting unit and reflected by an object.

[0019] According to the present disclosure, it is possible to provide an optical sensor cover and an optical sensor that suppress a decrease in light transmittance.

[0020] FIG. 1 is a perspective view schematically showing an example of the configuration of an optical sensor according to a first embodiment. FIG. 2 is a cross-sectional view of the optical sensor cover of the optical sensor according to the first embodiment, taken along line A-A shown in FIG. 1. FIG. 3 is a front view of the optical sensor cover in the optical sensor according to the first embodiment. FIG. 4 is a schematic view for explaining a specific example of length measured at a roughness of 10 mm. FIG. 5 is a front view of the optical sensor cover in the optical sensor according to a second embodiment. FIG. 6 is a diagram showing an example of divided wiring provided in the heating element in the optical sensor cover of the optical sensor according to the second embodiment. FIG. 7 is a diagram showing the results of a temperature distribution simulation of the substrate of the optical sensor cover in the optical sensors according to the first and second embodiments. FIG. 8 is a front view of the optical sensor cover in the optical sensor according to the third embodiment. FIG. 9 is a diagram showing the results of a temperature distribution simulation of the substrate of the optical sensor cover in the optical sensor according to the third embodiment.

[0021] Hereinafter, embodiments will be described with reference to the drawings. Note that for ease of understanding, the scale of each component in the drawings may differ from the actual scale. Directions such as parallel, right-angled, orthogonal, horizontal, vertical, up, down, left, and right are permitted to have deviations to the extent that they do not impair the functions and effects of the embodiments. The shape of corners is not limited to right angles and may be rounded. Parallel, right-angled, orthogonal, horizontal, and vertical may include approximately parallel, approximately right-angled, approximately orthogonal, approximately horizontal, and approximately vertical.

[0022] In this specification, a three-dimensional Cartesian coordinate system of three axes (X-axis, Y-axis, and Z-axis) is used, with the width or horizontal direction of the optical sensor cover being the X-axis direction, the height or vertical direction of the optical sensor cover being the Y-axis direction, and the thickness direction of the optical sensor cover being the Z-axis direction. The side toward which the arrow in the X-axis direction points is the +X-axis direction, and the opposite side is the -X-axis direction. The side toward which the arrow in the Y-axis direction points is the +Y-axis direction, and the opposite side is the -Y-axis direction. The side toward which the arrow in the Z-axis direction points is the +Z-axis direction, and the opposite side is the -Z-axis direction.

[0023] The X-axis direction, Y-axis direction, and Z-axis direction represent directions parallel to the X-axis, Y-axis, and Z-axis, respectively. The X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. A direction parallel to the X-axis direction or a direction parallel to the Y-axis direction may be referred to as an in-plane direction. A direction parallel to the Z-axis direction may be referred to as a perpendicular-to-plane direction. The XY plane, YZ plane, and ZX plane represent imaginary planes parallel to the X-axis direction and Y-axis direction, imaginary planes parallel to the Y-axis direction and Z-axis direction, and imaginary planes parallel to the Z-axis direction and X-axis direction, respectively.

[0024] [First embodiment] An optical sensor 1 according to the first embodiment will be described. FIG. 1 is a perspective view schematically illustrating an example of an optical sensor 1 according to the first embodiment. The optical sensor 1 is a distance measurement sensor that measures the distance to an object. However, the optical sensor 1 is not limited to a distance measurement sensor, and may be another optical sensor. Examples of other optical sensors include an imaging device such as a camera that is installed in a moving body such as a vehicle and captures images of objects outside the moving body. Note that in this specification, the symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0025] 1 , the optical sensor 1 includes a housing 10, an optical element including a light-emitting unit 21 and a light-receiving unit 22, and an optical sensor cover 30. The optical sensor 1 also includes optical members such as an optical filter 41, lenses 42a and 42b, and a diffuser 43. The optical sensor 1 also includes electronic circuits such as a distance measuring circuit that measures the distance to an object based on a light reception signal from the light-receiving unit 22.

[0026] <Housing 10> The housing 10 has a top surface 11 located on the +Y axis direction side, a bottom surface 12 located on the -Y axis direction side, and three side surfaces 13a, 13b, and 13c connecting the top surface 11 and the bottom surface 12. The housing 10 has an outer shape of a rectangular parallelepiped, but is not limited to this. The housing 10 may have other shapes such as a cube, a sphere, or an ellipsoid.

[0027] The housing 10 accommodates the light projecting unit 21, the light receiving unit 22, the optical filter 41, the lenses 42a and 42b, and the diffuser plate 43. The housing 10 of this embodiment also includes an opening region on the −Z axis direction side for holding the optical sensor cover 30.

[0028] The material constituting the housing 10 is not limited. Examples of materials constituting the housing 10 include resin and metal. The optical sensor cover 30 heats its surface by generating heat from a linear heating element 33 (see FIG. 3 ) provided on the optical sensor cover 30 to remove condensation, frost, snow, etc. (hereinafter referred to as “condensation, etc.”) adhering to the surface of the optical sensor cover 30. If the housing 10 is made of a material with high thermal conductivity, such as metal, directly fitting the optical sensor cover 30 into the opening region of the housing 10 may cause heat from the optical sensor cover 30 to dissipate into the housing 10, hindering the removal function of condensation, etc. To prevent this, the housing 10 preferably further includes a heat insulating material 15. The position of the heat insulating material 15 is optional, but it is preferably provided between the edge of the opening region of the housing 10 and the optical sensor cover 30.

[0029] <Optical Element> The light projecting unit 21 in this embodiment is a light emitting element such as a semiconductor laser or an LED (Light Emitting Diode) that projects near-infrared light. The light projecting unit 21 projects near-infrared light. The near-infrared light passes through the lens 42a, the diffuser 43, and the optical sensor cover 30, and is projected onto an external object. However, depending on the type of optical sensor 1, the light projecting unit 21 may project light belonging to another wavelength range, such as visible light. In this specification, "near-infrared light" refers to light belonging to a wavelength range of 800 nm to 2500 nm.

[0030] The light receiving unit 22 in this embodiment is a light receiving element such as a photodiode, a charge coupled device (CCD), or a complementary metal oxide semiconductor (CMOS). The near-infrared light projected from the light projecting unit 21 is reflected by an object and then returns to the optical sensor 1. The light receiving unit 22 receives reflected light (near-infrared light) that has passed through the optical sensor cover 30, the lens 42b, and the optical filter 41. The light receiving unit 22 outputs a light receiving signal derived from the reflected light to a signal processing unit such as a distance measuring circuit.

[0031] <Optical sensor cover 30> The configuration of the optical sensor cover 30 will be described with reference to Figures 2 and 3. Figure 2 is a cross-sectional view of the optical sensor cover 30 taken along line A-A shown in Figure 1. Figure 3 is a view of the optical sensor cover 30 as seen from the +Z axis direction. Note that viewing an object such as the optical sensor cover 30 from the +Z direction side is referred to as a "front view."

[0032] 2, the optical sensor cover 30 includes a light-transmitting substrate 31. In this embodiment, the substrate 31 is a glass substrate that transmits near-infrared light. Examples of the glass include alkali-free borosilicate glass, borosilicate glass, soda-lime glass, high-silica glass, and other oxide-based glasses containing silicon oxide as a main component.

[0033] The substrate 31 preferably blocks visible light to prevent the inside of the housing 10 from being viewed. However, depending on the type of optical sensor 1, the substrate 31 may be transparent to visible light. The substrate 31 in this embodiment is a flat plate-like member parallel to the XY plane. However, the substrate 31 may also have a curved surface.

[0034] The optical sensor cover 30 further includes a plurality of optical thin films 32a, 32b bonded to a principal surface 31a (hereinafter referred to as the "outer surface 31a") on the -Z axis direction side of the substrate 31 and a principal surface 31b (hereinafter referred to as the "inner surface 31b") on the +Z axis direction side of the substrate 31. Each of the optical thin films 32a, 32b in this embodiment is an anti-reflection film that prevents reflection of near-infrared light. However, the type of the optical thin films 32a, 32b is not limited to an anti-reflection film.

[0035] The optical sensor cover 30 is required to have high light transmittance. However, if condensation or the like adheres to the outer surface 31a of the substrate 31 or the optical thin film 32a, the light transmittance decreases. Therefore, the optical sensor cover 30 includes a linear heating element 33 (hereinafter simply referred to as the "heating element 33") that heats the substrate 31 to remove condensation or the like. The optical sensor cover 30 also includes a pair of electrodes 34a and 34b that pass current to the heating element 33. In this embodiment, the heating element 33 is a substantially circumferential member extending from the electrode 34a to the electrode 34b. However, the heating element 33 is not limited to having a substantially circumferential shape. The heating element 33 may have, for example, a folded structure. The folded structure will be described separately with reference to FIG. 8. Regardless of the shape, however, the overlapping area between the heating element 33 and the substrate 31 in a front view is 3% or less of the total area of ​​the substrate 31. If this overlapping area is 3% or less, the effect of the heating element 33 on transmitted light can be virtually ignored.

[0036] The pair of electrodes 34a, 34b are connected to both ends of the heating element 33. For example, if the electrode 34a is a positive electrode and the electrode 34b is a negative electrode, current flows from the electrode 34a to the electrode 34b through the heating element 33. On the other hand, if the electrode 34a is a negative electrode and the electrode 34b is a positive electrode, current flows from the electrode 34b to the electrode 34a through the heating element 33. When current flows through the heating element 33, the heating element 33 generates heat. As a result, the substrate 31 is heated.

[0037] In this embodiment, the heating element 33 and the electrodes 34a, 34b are provided on the inner surface 31b of the substrate 31. However, the positions of the heating element 33 and the electrodes 34a, 34b are not limited to this. The material constituting the heating element 33 is a conductive material such as a metal. Examples of materials constituting the heating element 33 include gold, silver, copper, tin, aluminum, and alloys using these.

[0038] Because the heating element 33 is linear, the overlapping area between the heating element 33 and the substrate 31 can be reduced compared to a planar heating element such as a transparent conductive film. That is, the heating element 33 ensures a wide area on the substrate 31 through which near-infrared light passes. As a result, a decrease in the light transmittance of the optical sensor cover 30 is suppressed. Furthermore, in order to widen the area through which near-infrared light passes on the substrate 31, the heating element 33 is positioned close to the edge 37 of the substrate 31.

[0039] The heating element 33 is composed of a plurality of divided wirings 331. Each of the plurality of divided wirings 331 is defined by a plurality of virtual square lattices 35 arranged in the in-plane direction of the substrate 31. For example, each of the plurality of virtual square lattices 35 is arranged in a matrix in each of the X-axis direction and the Y-axis direction. In Fig. 3, the reference numeral 35 is attached only to the four outer sides of the substrate 31, but the lattices inside thereof indicated by dashed lines are also virtual square lattices 35.

[0040] The multiple virtual square lattices 35 are not square lattices that actually appear on the substrate 31, but are virtually set square lattices. Each of the multiple virtual square lattices 35 is a virtual square lattice with a side length of 10 mm. In this embodiment, one side of the virtual square lattice 35 along the X-axis direction is 10 mm, and one side along the Y-axis direction is 10 mm. However, the reference point (e.g., the origin of the XY coordinate system) for determining the position of each virtual square lattice 35 (e.g., the center position of each virtual square lattice 35) is arbitrary. Furthermore, the angle between one side of the virtual square lattice 35 and the X-axis direction or the Y-axis direction is arbitrary.

[0041] Each of the multiple divided wirings 331 is continuous with another adjacent divided wiring 331. That is, each of the multiple divided wirings 331 is connected in series with the other divided wirings 331. The boundary of each of the multiple divided wirings 331 is defined by one side of the virtual square lattice 35. Therefore, the boundary of each of the multiple divided wirings 331 is not visible from the outside, but is virtual.

[0042] The multiple split wirings 331 include split wirings 331 arranged at a distance of 20 mm or less from the edge 37 of the substrate 31. Among these, the following split wirings 331 are referred to as "first split wirings." That is, the first split wirings 331 are split wirings 331 in which the actual length of the first split wiring is L'n, the length of the first split wiring measured at a roughness of 10 mm is Ln, and L'n / Ln is less than 1.2. In the case of FIG. 3 , of the multiple split wirings 331, split wirings 331F1, 331F2, 331F3, ..., 331F16 correspond to the first split wirings. The split wirings 331 corresponding to the first split wirings are collectively referred to as "first split wirings 331F." The "length measured at a roughness of 10 mm" will be described separately with reference to FIG. 4 . "L'n / Ln" means the value obtained by dividing the actual length L'n by the length Ln of the first divided wiring measured at a coarseness of 10 mm. In other words, in this specification, a term including " / " means a value obtained by dividing any number by another number. For example, when written as "A / B", it means the value obtained by dividing number A by number B. The same applies to the following terms including " / ".

[0043] The split wiring 331 includes not only the "first split wiring" described above but also a "second split wiring." The second split wiring is a split wiring 331 of the split wiring 331 excluding the first split wiring 331F, where L'm is the actual length of the second split wiring and Lm is the length of the second split wiring measured at a roughness of 10 mm, and L'm / Lm is less than 1.2, and the split wiring 331 does not include a position that is 20 mm or less away from the edge 37 of the substrate 31. In the case of FIG. 3 , the split wirings 331S1 and 331S2 correspond to the second split wiring. Furthermore, if there is no split wiring 331 other than the first split wiring 331F that does not include a position that is 20 mm or less from the edge 37 of the substrate 31 (for example, if the heating element 33 is wired so that the split wirings 331S1 and 331S2 shown in FIG. 3 do not exist), the split wiring 331 in which L'm / Lm is less than 1.2 and that includes the position farthest from the edge 37 of the substrate 31 among the split wirings 331 other than the first split wiring 331F is defined as the second split wiring. Here, "the split wiring 331 that includes the position farthest from the edge 37 of the substrate 31" refers to the split wiring 331 with the longest distance when measuring the distance from each split wiring 331 to the nearest edge 37 for each split wiring 331 other than the first split wiring 331F. The same applies to other embodiments. For example, the split wiring 331S3 shown in FIG. 3 corresponds to the second split wiring.

[0044] The edge 37 of the substrate 31 may be an upper edge 37a located on the +Y-axis direction side of the substrate 31, or a lower edge 37b located on the −Y-axis direction side of the substrate 31. The edge 37 of the substrate 31 may also be a right edge 37c located on the −X-axis direction side of the substrate 31, or a left edge 37d located on the +X-axis direction side of the substrate 31.

[0045] <Average resistance value of split wiring 331> If no special consideration is given to the shape or line width of each split wiring 331 in the heating element 33, differences in the position and wiring density of each split wiring 331 (the length of the split wiring 331 included in the virtual square lattice 35 when viewed from the front) may cause the heat generation density within the substrate 31 to be uneven, resulting in temperature unevenness in the substrate 31.

[0046] In particular, the peripheral region of the first divided wiring 331F arranged near the edge 37 may become a hot spot where the temperature locally rises because the movement of heat flow diffusing from the first divided wiring 331F is hindered by the edge 37. Furthermore, since the optical sensor cover 30 is a member facing the outside, it is undesirable for hot spots to occur on the outside of the substrate 31. Therefore, it is desirable to suppress the occurrence of hot spots on the outside of the substrate 31. Note that a heating element 33 in which no special innovations are made in the shape or line width of each divided wiring 331 is referred to as a "conventional heating element."

[0047] The first divided wirings 331F having the following configuration can suppress the occurrence of hot spots on the substrate 31. Specifically, the average resistance value Rn / Ln of 50% or more of all the first divided wirings 331F is lower than the average resistance value Rm / Lm of the second divided wirings. Furthermore, the average resistance value Rn / Ln of 90% or less of all the first divided wirings 331F may be lower than the average resistance value Rm / Lm of the second divided wirings. The shape and line width of the corresponding first divided wirings 331F are adjusted so that the average resistance value Rn / Ln of 50% or more of the first divided wirings 331F is lower than the average resistance value Rm / Lm of the second divided wirings. The average resistance value Rn / Ln of the first divided wirings 331F and the average resistance value Rm / Lm of the second divided wirings will be described separately. Any method can be used to adjust the shape and line width of each first divided wiring 331F, but examples include reducing the number of curved portions of the first divided wiring 331F, or reducing the wiring density by making the curvature of the curved portions gentler, or making the line width of the first divided wiring 331F wider than the average line width of the heating element 33.

[0048] A specific example of the "length measured at a rough luminance of 10 mm" in the divided wiring 331 will be described with reference to Fig. 4. Fig. 4 is a schematic diagram for explaining a specific example of the length measured at a rough luminance of 10 mm. Hereinafter, the "length measured at a rough luminance of 10 mm" will be referred to as the "coarse luminance length."

[0049] To measure the coarse visibility length of the divided wiring 331, multiple virtual square lattices with sides of 10 mm are arranged on the XY plane. These virtual square lattices are referred to as "virtual square lattices for measuring the coarse visibility length." The virtual square lattices for measuring the coarse visibility length are the same as the virtual square lattice 35 that defines the divided wiring 331. Hereinafter, the virtual square lattice for measuring the coarse visibility length will be described as the virtual square lattice 35.

[0050] FIG. 4A shows one virtual square lattice 35 and one divided wiring 331 (first divided wiring 331F or second divided wiring) included in this virtual square lattice 35. First, the length of a straight line L1 connecting intersections 35A and 35B between the virtual square lattice 35 and the divided wiring 331 is measured. Intersections 35A and 35B correspond to both end points of the divided wiring 331. The straight line L1 corresponds to the line segment connecting both end points of the divided wiring 331. The length of the straight line L1 corresponds to the coarse grain length of the divided wiring 331. Note that the virtual square lattice 35 shown in FIG. 4 is a virtual square lattice 35 that includes one side (base) that overlaps with a portion of the edge 37 of the substrate 31. However, the coarse grain lengths of the divided wirings 331 defined by other virtual square lattices 35 are also measured in a similar manner. Furthermore, the intersections 35A and 35B between the virtual square lattice 35 and the divided wiring 331 may intersect with any two sides of the virtual square lattice 35, respectively.

[0051] As shown in Figure 4 (b), if there is only one intersection between the split wiring 331 and the virtual square lattice 35, for example, the straight line L2 connecting the intersection 35A between the split wiring 331 and the virtual square lattice 35 and the end 331E1 of the split wiring 331 that does not intersect with the virtual square lattice 35 may be the coarse grain length.

[0052] In this embodiment, the average resistance of each first divided wiring 331F is a resistance value defined as "Rn / Ln" using the resistance value Rn of the first divided wiring 331F and the coarse length Ln of the first divided wiring 331F. The resistance value Rn of the first divided wiring 331F is determined from the potential difference between both ends of the first divided wiring 331F and the current value of the current flowing through the first divided wiring 331F, measured at a wiring temperature of 20°C to 30°C, for example. The potential difference and current value between both ends of the first divided wiring 331F can be obtained by identifying locations corresponding to the positions of both ends of the first divided wiring 331F based on coordinate information such as the X-axis coordinate and the Y-axis coordinate, and then measuring the potential difference and current value between the two locations.

[0053] In this embodiment, when the resistance of the second divided wiring is Rm, the coarse-grain length of the second divided wiring is Lm, and the average resistance of the second divided wiring is Rm / Lm (m is a natural number), the average resistance Rn / Ln of the first divided wiring 331F at 50% or more is smaller than the average resistance Rm / Lm of the second divided wiring. Furthermore, the average resistance Rn / Ln of the first divided wiring 331F at 50% or more is preferably 0.01 to 0.99 times, and more preferably 0.3 to 0.95 times, the average resistance Rn / Ln of the second divided wiring. By setting the relative value of the average resistance Rn / Ln to Rm / Lm within this range, the occurrence of hot spots on the substrate 31 can be more effectively suppressed. When there are multiple second divided wirings, the above holds true for each m.

[0054] On the other hand, if the average resistance value Rn / Ln of 50% or more of the first divided wirings 331F is less than 0.01 times Rm / Lm, the average resistance value Rn / Ln of the first divided wirings 331F is too small, and as a result, the temperature in the peripheral region of the first divided wirings 331F may become relatively low compared to the average temperature of the substrate 31. Furthermore, if the average resistance value Rn / Ln of 50% or more of the first divided wirings 331F exceeds 0.99 times the average resistance value Rm / Lm of the heating element 33, the occurrence of hot spots may not be sufficiently suppressed.

[0055] Second Embodiment An optical sensor 1A according to a second embodiment will be described. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0056] The optical sensor 1A according to the second embodiment, like the first embodiment, includes a housing 10 and an optical element including a light-emitting unit 21 and a light-receiving unit 22 (see FIG. 1). The optical sensor 1A according to the second embodiment also includes an optical sensor cover 30A. Like the optical sensor cover 30 according to the first embodiment, the optical sensor cover 30A is a member that protects the optical element housed in the housing 10. A linear heating element 33A (hereinafter simply referred to as "heating element 33A") in the optical sensor cover 30A differs from that of the first embodiment.

[0057] The configuration of the optical sensor cover 30A will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a front view of the optical sensor cover 30A. Fig. 6 is a diagram showing an example of divided wiring 331 provided on the heating element 33A of the optical sensor cover 30A.

[0058] 5, the optical sensor cover 30A includes a substrate 31, a heating element 33A, and electrodes 34a and 34b. The heating element 33A is a substantially circumferential member extending from the electrode 34a to the electrode 34b. The heating element 33A and the electrodes 34a and 34b are provided on the inner surface 31b of the substrate 31.

[0059] Electrodes 34a and 34b are disposed on both ends of the heating element 33A. When the electrode 34a is a positive electrode and the electrode 34b is a negative electrode, current flows from the electrode 34a through the heating element 33A to the electrode 34b. On the other hand, when the electrode 34a is a negative electrode and the electrode 34b is a positive electrode, current flows from the electrode 34b through the heating element 33A to the electrode 34a. The heating element 33A generates heat when a current flows through it. This heats the substrate 31. The heating element 33A is made of a conductive material such as gold, silver, copper, tin, aluminum, or an alloy using any of these.

[0060] As in the first embodiment, the heating element 33A is composed of a plurality of divided wirings 331. As in the first embodiment, each of the plurality of divided wirings 331 is defined by a plurality of virtual square lattices 35, each 10 mm on a side, arranged in the in-plane direction of the substrate 31.

[0061] For example, the split wiring 331 arranged at the corners of the circumferentially formed heating element 33A has a relatively high wiring density compared to the other split wirings 331. As the wiring density increases, heat flows diffusing from various parts of the split wiring 331 overlap with each other, increasing the heat density in the area surrounding the split wiring 331. In other words, the area surrounding the split wiring 331, which has a geometrically high wiring density, can become a hot spot.

[0062] As an example of a split wiring 331 with a high wiring density, a split wiring 331 having the following configuration is referred to as a "third split wiring 331G." The third split wiring 331G is a split wiring 331 in which L'k is the actual length of the third split wiring 331G and Lk is the coarse-grained length of the third split wiring, and L'k / Lk is 1.2 or greater. In the example shown in FIG. 5 , split wirings 331G1, 331G2, 331G3, 331G4, and 331G5 are examples of the third split wiring 331G. Examples of the third split wiring 331G include split wirings having at least one curved portion. For example, the third split wiring 331G may be a split wiring 331 curved in an arc as shown in FIG. 6( a) or a split wiring 331 having multiple curved portions and meandering as shown in FIG. 6( b). The L'k / Lk of the third split wiring 331G may be 10 or less.

[0063] Furthermore, the split wiring 331 includes a "second split wiring" in addition to the third split wiring 331G. The second split wiring is a split wiring 331 among the split wirings 331 excluding the third split wiring 331G, in which the actual length of the second split wiring is L'm and the coarseness length of the second split wiring is Lm, where L'm / Lm is less than 1.2, and which does not include a position that is 20 mm or less away from the edge 37 of the substrate 31. In the case of FIG. 5 , the split wirings 331T1 and 331T2 correspond to the second split wiring. Furthermore, if there is no split wiring 331 other than the third split wiring 331G that does not include a position that is 20 mm or less from the edge 37 of the substrate 31 (assuming that the heating element 33 is wired so that the split wirings 331T1 and 331T2 shown in FIG. 5 do not exist), the split wiring 331 for which L'm / Lm is less than 1.2 and that includes a position that is farthest from the edge 37 of the substrate 31 among the split wirings 331 other than the third split wiring 331G is defined as the second split wiring. In this case, for example, the split wiring 331T3 shown in FIG. 5 corresponds to the second split wiring.

[0064] In this embodiment, the average resistance of the third divided wiring 331G is a resistance value defined by "Rk / L'k" using the resistance value Rk of the third divided wiring 331G and the actual length L'k of the third divided wiring 331G. The average resistance of the second divided wiring is a resistance value defined by "Rm / Lm" using the resistance value Rm of the second divided wiring 331G and the coarse length Lm of the second divided wiring. The resistance value Rk of the third divided wiring 331G is calculated from the potential difference between both ends of the third divided wiring 331G and the current value of the current flowing through the third divided wiring 331G, measured at a wiring temperature of 20°C to 30°C, for example. The potential difference and current value between both ends of the third divided wiring 331G are obtained by identifying locations corresponding to the positions of both ends of the third divided wiring 331G based on coordinate information such as the X-axis coordinate and the Y-axis coordinate, and then measuring the potential difference and current value between the two locations.

[0065] In this embodiment, the average resistance value Rk / L'k of 50% or more of all the third divided wirings 331G is lower than the average resistance value Rm / Lm of the second divided wirings. That is, the shape and line width of the third divided wirings 331G are adjusted so that the average resistance value of 50% or more of the third divided wirings 331G is lower than the average resistance value Rm / Lm of the second divided wirings. Any method can be used to adjust the shape and line width of the third divided wirings 331G. Examples of such methods include reducing the number of curved portions of the third divided wirings 331G or reducing the curvature of the curved portions to reduce the wiring density, or making the line width of the third divided wirings 331G wider than the average line width of the heating elements 33A.

[0066] The average resistance Rk / L'k of the third divided wirings 331G that is 50% or more is preferably 0.01 to 0.99 times, and more preferably 0.3 to 0.95 times, the average resistance Rm / Lm. By setting the relative value of the average resistance Rk / L'k to the average resistance Rm / Lm in this range, the occurrence of hot spots on the substrate 31 can be more effectively suppressed.

[0067] The divided wiring 331 constituting the heating element 33A of the second embodiment may include the first divided wiring 331F of the first embodiment in addition to the third divided wiring 331G. Similarly, the divided wiring 331 constituting the heating element 33 of the first embodiment may include the third divided wiring 331G of the second embodiment in addition to the first divided wiring 331F.

[0068] [Temperature Distribution Simulation] Fig. 7(a) shows the results of a temperature distribution simulation on the outer surface 31a of the substrate 31 in the first and second embodiments. For comparison, Fig. 7(b) shows the results of a temperature distribution simulation on the outer surface 31a of a substrate 31 including a conventional heating element.

[0069] Region 38a shown by the dashed line in Figure 7(a) is a region that includes heating elements 33 and 33A. The temperature of outer surface 31a of substrate 31 decreases with increasing distance from region 38a. Region 38b shown by the dashed line in Figure 7(b) is a region that includes a conventional heating element. The temperature of outer surface 31a of substrate 31 decreases with increasing distance from region 38b.

[0070] In the substrate 31 including the conventional heating element shown in Figure 7(b), the temperature of region 39m and its vicinity rises within region 38b, creating hot spots where the temperature rises locally. In contrast, in the substrate 31 of the first and second embodiments shown in Figure 7(a), multiple approximately annular regions 39a-39k, each with a uniform temperature, are formed within region 38a, eliminating temperature unevenness. Furthermore, in the substrate 31 shown in Figure 7(a), high-temperature regions are widely distributed, which can prevent condensation and other problems from forming in the effective area through which near-infrared light emitted from the light-emitting unit 21 and near-infrared light received by the light-receiving unit 22 passes.

[0071] Third Embodiment An optical sensor 1B according to a third embodiment will be described. In the third embodiment, the same components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0072] Similar to the previously described embodiments, the optical sensor 1B according to the third embodiment includes a housing 10 and an optical element including a light-emitting unit 21 and a light-receiving unit 22 (see FIG. 1). Similar to the optical sensor covers 30 and 30A, the optical sensor cover 30B is a member that protects the optical element housed in the housing 10. A linear heating element 33B (hereinafter simply referred to as "heating element 33B") in the optical sensor cover 30B differs from the previously described embodiments.

[0073] The configuration of the optical sensor cover 30B will be described with reference to Figure 8. Figure 8 is a front view of the optical sensor cover 30B. As shown in Figure 8, the optical sensor cover 30B includes a substrate 31, a heating element 33B, and electrodes 34a and 34b. The heating element 33B is a member having a folded structure that includes folded portions at multiple locations from the electrode 34a to the electrode 34b. The heating element 33B and the electrodes 34a and 34b are provided on, for example, the inner surface 31b of the substrate 31.

[0074] Electrodes 34a and 34b are disposed on both ends of the heating element 33B. When the electrode 34a is a positive electrode and the electrode 34b is a negative electrode, current flows from the electrode 34a through the heating element 33B to the electrode 34b. On the other hand, when the electrode 34a is a negative electrode and the electrode 34b is a positive electrode, current flows from the electrode 34b through the heating element 33B to the electrode 34a. The heating element 33B generates heat when a current flows through it. This heats the substrate 31. The heating element 33B is made of a conductive material such as gold, silver, copper, tin, aluminum, or an alloy using any of these.

[0075] As in the previous embodiment, the heating element 33B is composed of a plurality of divided wirings 331. Each of the divided wirings 331 is defined by a plurality of virtual square lattices 35, each 10 mm on a side, arranged in the in-plane direction of the substrate 31.

[0076] In this embodiment, the multiple split wirings 331 include split wirings 331 arranged at a distance of 20 mm or less from the edge 37 of the substrate 31 and split wirings 331 having a relatively high wiring density compared to the other split wirings 331. The heating element 33B of this embodiment includes, for example, the following three types of split wirings 331. The first type of split wiring 331 corresponds to the first split wiring 331F of the first embodiment. That is, this split wiring 331 has an actual length L'n, a coarse grain length Ln, L'n / Ln is less than 1.2, and includes a position at a distance of 20 mm or less from the edge 37 of the substrate 31. The second type of split wiring 331 corresponds to the third split wiring 331G of the second embodiment. This split wiring 331 has an actual length L'k, a coarse grain length Lk, and L'k / Lk is 1.2 or more. These split wirings are collectively referred to as "split wirings 331H." In the example shown in FIG. 8, divided wirings 331H1 to 331H26 correspond to divided wiring 331H.

[0077] The third type of split wiring 331 corresponds to the second split wiring in the first and second embodiments. That is, the second split wiring in this embodiment is a split wiring 331 among the split wirings 331 excluding split wiring 331H, in which the actual length of the second split wiring is L'm and the coarseness length of the second split wiring is Lm, where L'm / Lm is less than 1.2, and which does not include a position 20 mm or less from the edge 37 of the substrate 31. Furthermore, if there is no split wiring 331 among the split wirings 331 excluding split wiring 331H that does not include a position 20 mm or less from the edge 37 of the substrate 31, the split wiring 331 in which L'm / Lm is less than 1.2 and which includes the position farthest from the edge 37 of the substrate 31 among the split wirings 331 excluding split wiring 331H is defined as the second split wiring.

[0078] In this embodiment, the average resistance of each of the split wirings 331H corresponding to the first split wiring (e.g., split wirings 331H1 to 331H6, 331H8, 331H10, 331H11, 331H13, 331H15 to 331H26) is defined as "Rp / Lp" using the resistance Rp of the split wiring 331H and the coarse-grain length Lp of the split wiring 331H. Also, the average resistance of each of the split wirings 331H corresponding to the third split wiring (e.g., split wirings 331H7, 331H9, 331H12, 331H14) is defined as "Rp / L'p" using the resistance Rp of the split wiring 331H and the actual length L'p of the split wiring 331H. The divided wirings 331H in which the average resistance value Rp / Lp or the average resistance value Rp / L'p of each divided wiring 331H is lower than the average resistance value Rm / Lm of the second divided wirings account for 50% or more of all divided wirings 331H. Note that the resistance value Rp is an example of a "resistance value Rn" or a "resistance value Rk." The actual length L'p is an example of an "actual length L'n" or an "actual length L'k." The average resistance value Rp / Lp is an example of an "average resistance value Rn / Ln." The average resistance value Rp / L'p is an example of an "average resistance value Rk / L'k."

[0079] The average resistance Rp / Lp of split wiring 331H (split wiring 331H corresponding to the first split wiring), which is lower than the average resistance Rm / Lm of the second split wiring, is preferably 0.01 to 0.99 times, and more preferably 0.3 to 0.95 times, the average resistance Rm / Lm of the second split wiring. The average resistance Rp / L'p of split wiring 331H (split wiring 331H corresponding to the third split wiring), which is lower than the average resistance Rm / Lm of the second split wiring, is preferably 0.01 to 0.99 times, and more preferably 0.3 to 0.95 times, the average resistance Rm / Lm of the second split wiring.

[0080] [Temperature Distribution Simulation] Fig. 9(a) shows the results of a temperature distribution simulation on the outer surface 31a of the substrate 31 in the third embodiment. For comparison, Fig. 9(b) shows the results of a temperature distribution simulation on the outer surface 31a of a substrate 31 including a conventional heating element.

[0081] Region 48a indicated by a dashed line in FIG. 9(a) is the region including heating element 33B. Region 48b indicated by a dashed line in FIG. 9(b) is the region including the conventional heating element. As shown in FIG. 9(a), a high-temperature region is formed along heating element 33B. Furthermore, no hot spots where the temperature rises locally are formed. On the other hand, as shown in FIG. 9(b), in the conventional heating element, the temperature is locally high in regions 49b1 and 49b2 near the edge 37 of substrate 31, which include the bending portion of the heating element. Furthermore, in substrate 31 shown in FIG. 9(a), high-temperature regions are widely distributed, which can prevent condensation and the like from forming in the effective area through which near-infrared light projected from light-projecting unit 21 and near-infrared light received by light-receiving unit 22 passes.

[0082] The above describes in detail preferred embodiments, but the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0083] This application claims priority based on Japanese Patent Application No. 2023-193052 filed with the Japan Patent Office on November 13, 2023, the entire contents of which are incorporated herein by reference.

[0084] REFERENCE SIGNS LIST 1, 1A, 1B Optical sensor 10 Housing 21 Light-emitting section 22 Light-receiving section 30, 30A, 30B Optical sensor cover 31 Substrate 33, 33A, 33B Linear heating element 331, 331H Divided wiring 331F First divided wiring 331G Third divided wiring 35 Virtual square lattice 37 Edge of substrate

Claims

1. A light-transmitting substrate; and a linear heating element provided on the substrate, the heating element being composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of divided wirings including a first divided wiring and a second divided wiring, the first divided wiring being a divided wiring including a position at a distance of 20 mm or less from an edge of the substrate, the actual length of the first divided wiring being L'n and the length of the first divided wiring being Ln, the ratio L'n / Ln being less than 1.2, and the position being partitioned using a virtual square lattice with sides of 10 mm arranged in an in-plane direction of the substrate, The second split wiring is a split wiring in which, among the split wirings excluding the first split wiring, an actual length of the second split wiring is L'm and a length of the second split wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position that is 20 mm or less away from the edge of the substrate, or, when there is no split wiring in the split wirings excluding the first split wiring that does not include a position that is 20 mm or less away from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position that is the farthest from the edge of the substrate among the split wirings excluding the first split wiring; when a resistance value of the first split wiring is Rn, an average resistance value of the first split wiring is Rn / Ln, a resistance value of the second split wiring is Rm, and an average resistance value of the second split wiring is Rm / Lm, The average resistance value Rn / Ln of 50% or more of all the first divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

2. A light-transmitting substrate; and a linear heating element provided on the substrate, the heating element being composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of divided wirings including a third divided wiring and a second divided wiring, the third divided wiring being a divided wiring in which L'k is an actual length of the third divided wiring and Lk is a length of the third divided wiring measured at a roughness of 10 mm, and L'k / Lk is 1.2 or more, The second split wiring is a split wiring in which, among the split wirings excluding the third split wiring, an actual length of the second split wiring is L'm and a length of the second split wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position that is 20 mm or less away from the edge of the substrate, or, when there is no split wiring in the split wirings excluding the third split wiring that does not include a position that is 20 mm or less away from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position that is the farthest from the edge of the substrate among the split wirings excluding the third split wiring; when a resistance value of the third split wiring is Rk, an average resistance value of the third split wiring is Rk / L'k, a resistance value of the second split wiring is Rm, and an average resistance value of the second split wiring is Rm / Lm, the average resistance value Rk / L'k of 50% or more of all the third divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

3. The optical sensor cover according to claim 1, wherein the first divided wiring has at least one bent portion.

4. The optical sensor cover according to claim 2, wherein the third divided wiring has at least one bent portion.

5. The optical sensor cover according to claim 1, wherein the average resistance value Rn / Ln of the first divided wiring is 0.3 to 0.95 times the average resistance value Rm / Lm of the second divided wiring.

6. The optical sensor cover according to claim 2, wherein the average resistance value Rk / L'k of the third divided wiring is 0.3 to 0.95 times the average resistance value Rm / Lm of the second divided wiring.

7. The optical sensor cover according to claim 1, wherein the first divided wiring includes an area having a line width wider than an average line width of the heating element.

8. The optical sensor cover according to claim 2, wherein the third divided wiring includes an area having a line width wider than an average line width of the heating element.

9. The optical sensor cover according to claim 1 or 2, wherein the heating element contains at least one of gold, silver, copper, tin, aluminum, and alloys using these metals.

10. A housing, an optical element housed in the housing, and an optical sensor cover attached to the housing so as to cover the optical element, the optical sensor cover comprising: a light-transmitting substrate; and a linear heating element provided on the substrate, the heating element being composed of a plurality of divided wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of divided wirings including a first divided wiring and a second divided wiring, the first divided wiring being a divided wiring having an actual length L'n and a length of the first divided wiring measured at a roughness of 10 mm, L'n / Ln being less than 1.2, and including a position at a distance of 20 mm or less from an edge of the substrate, The second split wiring is a split wiring in which, among the split wirings excluding the first split wiring, an actual length of the second split wiring is L'm and a length of the second split wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position that is 20 mm or less away from the edge of the substrate, or, when there is no split wiring in the split wirings excluding the first split wiring that does not include a position that is 20 mm or less away from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position that is the farthest from the edge of the substrate among the split wirings excluding the first split wiring; when a resistance value of the first split wiring is Rn, an average resistance value of the first split wiring is Rn / Ln, a resistance value of the second split wiring is Rm, and an average resistance value of the second split wiring is Rm / Lm, the average resistance value Rn / Ln of 50% or more of all the first divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

11. A housing, an optical element housed in the housing, and an optical sensor cover attached to the housing so as to cover the optical element, the optical sensor cover comprising: a light-transmitting substrate; and a linear heating element provided on the substrate, the heating element being composed of a plurality of split wirings partitioned using a plurality of virtual square lattices with sides of 10 mm arranged in an in-plane direction of the substrate, the plurality of split wirings including a third split wiring and a second split wiring, the third split wiring being a split wiring in which the actual length of the third split wiring is L'k and the length of the third split wiring measured at a roughness of 10 mm is Lk, and L'k / Lk is 1.2 or more, The second split wiring is a split wiring in which, among the split wirings excluding the third split wiring, an actual length of the second split wiring is L'm and a length of the second split wiring measured at a roughness of 10 mm is Lm, and L'm / Lm is less than 1.2 and does not include a position that is 20 mm or less away from the edge of the substrate, or, when there is no split wiring in the split wirings excluding the third split wiring that does not include a position that is 20 mm or less away from the edge of the substrate, L'm / Lm is less than 1.2 and includes a position that is the farthest from the edge of the substrate among the split wirings excluding the third split wiring; when a resistance value of the third split wiring is Rk, an average resistance value of the third split wiring is Rk / L'k, a resistance value of the second split wiring is Rm, and an average resistance value of the second split wiring is Rm / Lm, the average resistance value Rk / L'k of 50% or more of all the third divided wirings is lower than the average resistance value Rm / Lm of the second divided wirings.

12. The optical sensor according to claim 10 or 11, wherein the housing is made of resin or metal, and when the housing is made of metal, a heat insulating material is provided between the housing and the substrate.

13. The optical sensor of claim 10 or 11, wherein the optical sensor is a distance measuring sensor, and the optical element includes a light-projecting section and a light-receiving section that receives light reflected from an object after light projected from the light-projecting section.

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