Distance measuring device

Abstract

A ranging device (1) comprises a transmission part (11), a reception part (12), a housing (100), a penetration part (200), and a heating part (50). The transmission part transmits a transmission wave. The reception part receives a reflected wave formed by the transmission wave reflecting off an object. The housing accommodates the transmission part and the reception part inside, and an opening (100a) for passage of the transmission wave and reception wave is formed therein. The penetration part is formed from a material through which the transmission wave and the reflected wave penetrate, and covers the opening. The heating part is formed from a metal in a mesh shape and is thereby provided with a plurality mesh openings (52), is arranged so as to at least partially cover the opening, and generates heat as a result of energizing of the metal and heats the penetration part.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This international application claims priority based on Japanese Patent Application No. 2022-64529, filed with the Japan Patent Office on April 8, 2022, the entire contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a distance measuring device that measures the distance to an object. [Background technology]

[0003] Patent document 1 describes a distance measuring device that measures the distance to an object by transmitting a transmission wave and receiving a reflected wave generated when the transmission wave is reflected by the object, in which an electric heating conductor is arranged excluding the transmission window, out of the transmission window through which the transmission wave passes and the reception window through which the reflected wave passes. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2015-506459 Summary of the Invention

[0005] After detailed investigation by the inventors, it was found that the technology described in Patent Document 1 has the problem that, because the electric heating conductor is arranged excluding the transmitting window, snow, water droplets, etc. adhering to the ranging device cannot be sufficiently removed, which makes it impossible to pass the transmitting wave through the transmitting window, and may result in a decrease in the ranging performance of the ranging device.

[0006] The present disclosure improves the ranging performance of a ranging device.

[0007] One aspect of the present disclosure is a distance measuring device including a transmitter, a receiver, a housing, a transmission unit, and a heating unit.

[0008] The transmitter is configured to transmit a transmission wave.

[0009] The receiving section is configured to receive a reflected wave generated when the transmitted wave is reflected by an object.

[0010] The housing accommodates the transmitting unit and the receiving unit therein, and has openings formed therein for passing the transmitted wave and the reflected wave.

[0011] The transmitting portion is formed of a material that transmits the transmitted wave and the reflected wave, and covers the opening.

[0012] The heating section is formed in a mesh shape from metal and has a plurality of mesh openings, is positioned to cover at least a portion of the openings, and is configured to generate heat by passing electricity through the metal, thereby heating the transmission section.

[0013] In the distance measuring device of the present disclosure configured as above, the heating unit is positioned to cover at least a portion of the opening. This allows the distance measuring device of the present disclosure to improve the ability of the heating unit to heat the transmission unit. This makes it possible to prevent the transmission wave and the reflected wave from being unable to pass through the transmission unit due to insufficient removal of snow, water droplets, etc., adhering to the distance measuring device.

[0014] Furthermore, in the distance measuring device of the present disclosure, the heating unit is formed in a metal mesh shape and has multiple mesh openings, so that even if the heating unit is arranged to cover part of the openings, the distance measuring device of the present disclosure can prevent the heating unit from blocking the transmitted wave and the reflected wave.

[0015] As described above, the distance measuring device of the present disclosure can improve the distance measuring performance of the distance measuring device. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing the appearance of a distance measuring device according to first to fifth embodiments. [Figure 2] FIG. 1 is an exploded perspective view of a distance measuring device according to first to fifth embodiments. [Figure 3] FIG. 2 is a perspective view of a detection module. [Figure 4] FIG. 1 is a plan view of a metal mesh heater according to a first embodiment. [Figure 5] FIG. 10 is a diagram showing the intensity distribution of a transmission wave. [Figure 6] FIG. 10 is a plan view of a metal mesh heater according to a second embodiment. [Figure 7] FIG. 10 is a plan view of a metal mesh heater according to a third embodiment. [Figure 8] FIG. 10 is a plan view of a metal mesh heater according to a fourth embodiment. [Figure 9] FIG. 10 is a side view of a metal mesh heater and an optical window according to a fifth embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing a schematic configuration of a distance measuring device according to a sixth embodiment. [Figure 11] FIG. 13 is a cross-sectional view showing a schematic configuration of a distance measuring device according to a seventh embodiment. [Figure 12] FIG. 10 is a plan view of a metal mesh heater according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] [First embodiment] A first embodiment of the present disclosure will be described below with reference to the drawings.

[0018] The distance measuring device 1 of this embodiment is mounted on a vehicle and used to measure the distance and direction to various objects around the vehicle.

[0019] As shown in FIG. 1, the distance measuring device 1 includes a housing 100, an optical window 200, and a heat sink 300.

[0020] The housing 100 is a rectangular parallelepiped box made of resin or metal and having an opening 100a on one of its six faces.

[0021] The optical window 200 is a resin or glass cover fixed to the housing 100 so as to cover the opening 100a of the housing 100. The laser light transmitted from the detection module 2 installed inside the housing 100 passes through the inside of the optical window 200.

[0022] Hereinafter, the direction along the longitudinal direction of the opening 100a, which is formed in a substantially rectangular shape, will be referred to as the X-axis direction, the direction along the short side of the opening 100a will be referred to as the Y-axis direction, and the direction perpendicular to the X-axis and Y-axis directions will be referred to as the Z-axis direction. Note that left and right in the X-axis direction and up and down in the Y-axis direction are defined as viewed from the opening 100a side of the housing 100. Furthermore, regarding front and back in the Z-axis direction, the opening 100a side of the housing 100 is defined as the front, and the depth side as the rear.

[0023] The heat sink 300 is installed on the outer surface of the housing 100 to dissipate heat generated inside the housing 100. In this embodiment, the heat sink 300 is installed on the top surface of the housing 100.

[0024] 2, the distance measuring device 1 further includes a detection module 2 and a control board 3 that controls the detection module 2. The detection module 2 and the control board 3 are housed inside a housing 100.

[0025] The detection module 2 includes a transmitting / receiving unit 10, an oscillating scanner 20, a polygon scanner 30, and a folding mirror 40.

[0026] 3, the transmitting / receiving unit 10 includes a transmitting section 11 and a receiving section 12. The transmitting section 11 and the receiving section 12 are housed inside the transmitting / receiving unit 10.

[0027] The transmitter 11 generates a laser beam and transmits the generated laser beam as a transmission wave. In this embodiment, the wavelength of the transmission wave is 1550 nm.

[0028] The receiver 12 receives, as a received wave, a reflected wave that is generated when the transmitted wave is reflected by an object.

[0029] The oscillating scanner 20 includes an oscillating mirror 21 and an oscillating motor 22 .

[0030] The oscillating mirror 21 is a flat plate-shaped member having a reflective surface that reflects laser light. The oscillating motor 22 has an output shaft 22a for outputting its rotational driving force. The oscillating mirror 21 is connected to the output shaft 22a so that its reflective surface rotates around the output shaft 22a, as shown by arrow L1. In this embodiment, the output shaft 22a is parallel to the Z-axis direction.

[0031] The polygon scanner 30 includes a polygon mirror 31 and a rotary motor 32 .

[0032] The polygon mirror 31 is a rotating polygonal mirror having a plurality of reflecting surfaces that reflect the laser light.

[0033] The rotary motor 32 has an output shaft 32a for outputting the rotational driving force. The polygon mirror 31 is connected to the output shaft 32a so that its reflective surface rotates around the output shaft 32a, as shown by arrow L2. In this embodiment, the output shaft 32a is parallel to the Y-axis direction.

[0034] The folding mirror 40 is a flat member having a reflective surface that reflects the laser light. The folding mirror 40 is installed so as to reflect, toward the oscillating mirror 21, the transmission wave that is transmitted from the transmitter 11 and reaches the folding mirror 40, and to reflect, toward the receiver 12, the reflected wave that is reflected by the oscillating mirror 21 and reaches the folding mirror 40.

[0035] Therefore, the distance measuring device 1 scans the transmission wave transmitted from the transmitter 11 in the horizontal direction along the X-axis direction by rotating the polygon mirror 31. Furthermore, the distance measuring device 1 scans the transmission wave transmitted from the transmitter 11 in the vertical direction along the Y-axis direction by oscillating the oscillating mirror 21.

[0036] In addition, the distance measuring device 1 receives reflected light that has passed through the optical window 200 from outside the housing 100 and entered the inside of the housing 100 at the receiving unit 12 by reflecting it in this order from the polygon mirror 31, the oscillating mirror 21, and the folding mirror 40.

[0037] A control unit (not shown) is mounted on the control board 3. The control unit controls the timing at which the transmitter 11 transmits a transmission wave in synchronization with the rotation of the oscillating mirror 21 and the polygon mirror 31.

[0038] The control unit then measures the distance to the object that reflected the transmitted wave based on the difference between the time when the transmitting unit 11 transmitted the transmitted wave and the time when the receiving unit 12 received the received wave. The control unit also measures the azimuth angle of the object that reflected the transmitted wave based on the scanning angles of the oscillating mirror 21 and the polygon mirror 31 when the transmitted wave was transmitted.

[0039] As shown in FIG. 4, the distance measuring device 1 includes a metal mesh heater 50.

[0040] The metal mesh heater 50 is formed by weaving a plurality of metal wires 51 made of, for example, silver or copper into a mesh shape, and is installed so as to cover the back surface of the optical window 200 (i.e., the inner surface of the optical window 200). Note that the metal mesh heater 50 may also be installed so as to cover the front surface of the optical window 200.

[0041] The metal mesh heater 50 heats the optical window 200 by passing electricity through the metal wires 51 to cause the metal wires 51 to generate heat.

[0042] The metal mesh heater 50 is formed in a mesh shape by a plurality of metal wires 51, and has a plurality of mesh openings 52 separated by the plurality of metal wires 51 into rectangular shapes.

[0043] The metal mesh heater 50 may be formed directly on the optical window 200 by printing, photolithography, etching, or the like. Alternatively, the metal mesh heater 50 formed in a film form may be attached to the optical window 200. Alternatively, the metal mesh heater 50 may be embedded in the optical window 200 by insert molding.

[0044] The opening width of the mesh opening 52 is set to be longer than the wavelength of the transmission wave that passes through the optical window 200 and shorter than the wavelength (for example, 3 mm in this embodiment) of the electromagnetic wave that becomes noise in the distance measuring device 1. In this embodiment, the opening width of the mesh opening 52 is 1 mm.

[0045] The metal mesh heater 50 is formed so that the ratio of the area of ​​the metal wires 51 that block the transmission wave to the area of ​​the transmission wave that passes through the optical window 200 is 10% or less.

[0046] The intensity distribution of laser light usually has a Gaussian shape, as shown in Fig. 5. In this embodiment, the area of ​​the transmitted wave is the area of ​​a circle whose diameter is the half-width in the intensity distribution of the transmitted wave.

[0047] The distance measuring device 1 configured in this manner includes a transmitting unit 11, a receiving unit 12, a housing 100, an optical window 200, and a metal mesh heater 50.

[0048] The transmitter 11 transmits a transmission wave. The receiver 12 receives a reflected wave that is generated when the transmission wave is reflected by an object.

[0049] The housing 100 accommodates the transmitting unit 11 and the receiving unit 12 therein, and has an opening 100a formed therein for passing the transmitted wave and the reflected wave.

[0050] The optical window 200 is made of a material that transmits the transmitted wave and the reflected wave, and covers the opening 100a.

[0051] The metal mesh heater 50 is formed in a mesh shape from metal and has multiple mesh openings 52, is positioned so as to cover at least a portion of the opening 100a, and generates heat by passing electricity through the metal, thereby heating the optical window 200.

[0052] In such a distance measuring device 1, the metal mesh heater 50 is arranged so as to cover at least a part of the opening 100a. Therefore, the distance measuring device 1 can improve the ability to heat the optical window 200 by the metal mesh heater 50. This makes it possible for the distance measuring device 1 to prevent a situation in which snow, water droplets, etc. adhering to the distance measuring device 1 cannot be sufficiently removed, preventing the transmitted wave and reflected wave from passing through the optical window 200.

[0053] Furthermore, in the distance measuring device 1, the metal mesh heater 50 is formed in a metal mesh shape and has a plurality of mesh openings 52. Therefore, even if the metal mesh heater 50 is arranged so as to cover part of the opening 100a, the distance measuring device 1 can prevent the transmitted wave and the reflected wave from being blocked by the metal mesh heater 50.

[0054] As a result, the distance measuring device 1 can improve the distance measuring performance of the distance measuring device 1.

[0055] Furthermore, in the distance measuring device 1, the metal mesh heater 50 is arranged so as to cover at least a part of the opening 100a, and the metal mesh heater 50 is formed in a mesh shape from metal. Therefore, the distance measuring device 1 can prevent electromagnetic waves that cause noise from passing through the optical window 200 and entering the housing 100.

[0056] In the embodiment described above, the optical window 200 corresponds to the transmitting portion, and the metal mesh heater 50 corresponds to the heating portion.

[0057] [Second embodiment] A second embodiment of the present disclosure will be described below with reference to the drawings. In the second embodiment, only the parts that are different from the first embodiment will be described. The same reference numerals will be used to designate common components.

[0058] The distance measuring device 1 of the second embodiment differs from the first embodiment in that the configuration of the metal mesh heater 50 is changed.

[0059] As shown in FIG. 6, the metal mesh heater 50 of the second embodiment is formed so that the metal mesh in the light-transmitting region R1 of the optical window 200, through which the transmitted wave passes, is denser than the metal mesh in the light-non-transmitting region R2 of the optical window 200, through which the transmitted wave does not pass.

[0060] The light-transmitting region R1 is formed in a rectangular shape in the center of the surface of the optical window 200. The light-non-transmitting region R2 is a region on the surface of the optical window 200 other than the light-transmitting region R1, and is formed to surround the periphery of the light-transmitting region R1.

[0061] Specifically, the opening width of the mesh openings 52 in the light-transmitting region R1 (hereinafter referred to as the mesh opening width) is longer than the mesh opening width in the non-light-transmitting region R2. Note that the mesh opening width in part of the non-light-transmitting region R2 may be shorter than the mesh opening width in the light-transmitting region R1.

[0062] In the distance measuring device 1 configured in this manner, the metal mesh heater 50 is formed so that the mesh opening width changes depending on the position that covers the opening 100a.

[0063] Specifically, the metal mesh heater 50 is formed so that a passing opening width setting condition is met in which the mesh opening width in the light-transmitting region R1, which is the region through which the transmitted wave and the reflected wave pass at the opening 100a, is set to be longer than the mesh opening width in at least a portion of the region other than the light-transmitting region R1 at the opening 100a (in this embodiment, the light-non-transmitting region R2).

[0064] In such a distance measuring device 1, the metal mesh heater 50 can be arranged more densely in the non-light-transmitting region R2 than in the light-transmitting region R1, thereby further improving the ability of the metal mesh heater 50 to heat the optical window 200 and further improving the ability of the metal mesh heater 50 to block noise.

[0065] In the above-described embodiment, the light-transmitting region R1 corresponds to the wave-passing region.

[0066] [Third embodiment] A third embodiment of the present disclosure will be described below with reference to the drawings. In the third embodiment, differences from the second embodiment will be described. The same reference numerals will be used to designate common components.

[0067] The distance measuring device 1 of the third embodiment differs from the second embodiment in that the configuration of the metal mesh heater 50 is changed.

[0068] 7, the metal mesh heater 50 of the third embodiment is formed so that the metal mesh in the lower region R3 of the optical window 200 is denser than the metal mesh in regions other than the lower region R3 of the optical window 200. The lower region R3 is a lower region on the surface of the optical window 200. Note that a portion of the lower region R3 may overlap with the light-transmitting region R1.

[0069] Specifically, the opening width of the mesh openings 52 in the lower region R3 is shorter than the opening width of the mesh openings 52 in regions other than the lower region R3.

[0070] In the distance measuring device 1 configured in this manner, the metal mesh heater 50 is formed so that a lower opening width setting condition is met, in which the mesh opening width in the lower region R3 corresponding to the lower region of the opening 100a is set to be shorter than the mesh opening width in the region corresponding to the region above the lower region R3 of the opening 100a.

[0071] When the distance measuring device 1 mounted on a vehicle transmits a transmission wave toward the front of the vehicle, most of the transmission wave transmitted downward from the direction of travel of the vehicle is reflected by the road surface. Therefore, the required detection distance for the transmission wave transmitted downward (i.e., the transmission wave that penetrates the lower region R3) is short.

[0072] Therefore, even if the optical performance of the distance measuring device 1 is reduced by densely arranging the metal mesh in the lower region R3, the effect on distance detection performance is small.

[0073] The distance measuring device 1 can improve the temperature rise performance in the lower region R3 of the optical window 200. Since the optical window 200 is disposed almost perpendicular to the road surface, even if snow adheres to the surface of the optical window 200, the snow adhering to the lower region R3 melts, making it easier for all of the snow adhering to the surface of the optical window 200 to fall off.

[0074] Therefore, the distance measuring device 1 of the third embodiment can further improve the ability to remove snow adhering to the distance measuring device 1.

[0075] In the embodiment described above, the lower region R3 corresponds to the region below the opening, and the region of the optical window 200 other than the lower region R3 corresponds to the region above the opening.

[0076] [Fourth embodiment] A fourth embodiment of the present disclosure will be described below with reference to the drawings. In the fourth embodiment, differences from the second embodiment will be described. The same reference numerals will be used to designate common components.

[0077] The distance measuring device 1 of the fourth embodiment differs from the second embodiment in that the configuration of the metal mesh heater 50 is changed.

[0078] 8, the metal mesh heater 50 of the third embodiment is formed so that the metal mesh in the left region R4 and the right region R5 of the optical window 200 is denser than the metal mesh in regions other than the left region R4 and the right region R5 of the optical window 200. The left region R4 is the region on the left side of the surface of the optical window 200. The right region R5 is the region on the right side of the surface of the optical window 200. Note that the left region R4 and the right region R5 may partially overlap with the light-transmitting region R1.

[0079] Specifically, the opening width of the mesh openings 52 in the left region R4 and the right region R5 is shorter than the opening width of the mesh openings 52 in regions other than the left region R4 and the right region R5.

[0080] In the distance measuring device 1 configured in this manner, the metal mesh heater 50 is formed so that the left and right side opening width setting conditions are met, in which the mesh opening width in the right region R5 and left region R4 corresponding to the right and left regions of the opening 100a is set to be shorter than the mesh opening width in regions corresponding to regions other than the right region R5 and left region R4 of the opening 100a.

[0081] When the distance measuring device 1 mounted on a vehicle transmits a transmission wave toward the front of the vehicle, the transmission wave transmitted to the left or right of the vehicle's traveling direction is reflected by a wall or vehicle on the right or left side of the vehicle mounting the distance measuring device 1. Therefore, the required detection distance is shorter for transmission waves transmitted to the left or right (i.e., transmission waves that pass through the left region R4 or the right region R5).

[0082] Therefore, even if the optical performance of the distance measuring device 1 is reduced by densely arranging the metal mesh in the left region R4 and the right region R5, the effect on the distance detection performance is small.

[0083] The distance measuring device 1 can improve the temperature rise performance in the left region R4 and the right region R5 of the optical window 200. Because the optical window 200 is disposed substantially perpendicular to the road surface, even if snow adheres to the surface of the optical window 200, the snow adhering to the left region R4 and the right region R5 melts, making it easier for all of the snow adhering to the surface of the optical window 200 to fall off.

[0084] Therefore, the distance measuring device 1 of the fourth embodiment can further improve the ability to remove snow adhering to the distance measuring device 1.

[0085] In the embodiment described above, the left region R4 and the right region R5 correspond to the left and right side regions of the opening, and the region of the optical window 200 other than the left region R4 and the right region R5 corresponds to the central region of the opening.

[0086] [Fifth embodiment] A fifth embodiment of the present disclosure will be described below with reference to the drawings. In the fifth embodiment, only the parts that are different from the first embodiment will be described. The same reference numerals will be used to designate common components.

[0087] The distance measuring device 1 of the fifth embodiment differs from the first embodiment in that the configuration of the metal mesh heater 50 is changed.

[0088] As shown in FIG. 9, the metal mesh heater 50 of the fifth embodiment differs from the first embodiment in that it includes a blackening treatment layer 53, an overcoat layer 54, and an AR coating layer 55.

[0089] The metal mesh heater 50 has a structure in which a plurality of metal wires 51, a blackening treatment layer 53, an overcoat layer 54, and an AR coating layer 55 are sequentially stacked on the rear surface of the optical window 200 in order from the side closest to the optical window 200.

[0090] The blackening layer 53 is formed by performing a surface treatment on the metal wires 51 that has the effect of reducing the reflectance with respect to the wavelength of the transmission wave.

[0091] The overcoat layer 54 is a film or resin formed on the blackened layer 53 to protect the metal wires 51 .

[0092] The AR coating layer 55 is a film, resin, or metal that has the effect of reducing the reflectance for the wavelength of the transmission wave.

[0093] In the distance measuring device 1 configured in this manner, the metal mesh heater 50 includes a blackening layer 53, an overcoat layer 54, and an AR coating layer 55 on the metal wire 51 that separates adjacent mesh openings 52. The blackening layer 53 is a layer that has been subjected to a reflectance reduction process to reduce reflection of the transmitted wave and the reflected wave on the metal wire 51. The overcoat layer 54 is a layer that protects the surface of the metal wire 51. The AR coating layer 55 is a layer that reduces reflection of the transmitted wave and the reflected wave.

[0094] Such a distance measuring device 1 can reduce the reflection of the transmitted wave and the reflected wave, and can prevent the metal mesh heater 50 from being damaged.

[0095] In the embodiment described above, the blackening treatment layer 53 corresponds to a reflectance reducing treatment layer, the overcoat layer 54 corresponds to a protective layer, and the AR coating layer 55 corresponds to a reflection suppressing layer.

[0096] [Sixth embodiment] A sixth embodiment of the present disclosure will be described below with reference to the drawings. In the sixth embodiment, differences from the first embodiment will be described. The same reference numerals will be used to designate common components.

[0097] As shown in FIG. 10, the distance measuring device 1 of the sixth embodiment differs from the first embodiment in that the detection module 2 and the control board 3 are omitted and a detection board 6 is added.

[0098] The detection board 6 is housed inside the housing 100. The detection board 6 employs an electronic scanning system and includes a control unit, a transmitting array antenna, and a receiving array antenna, none of which are shown.

[0099] The transmitting array antenna has a plurality of transmitting antenna elements arranged at regular intervals on the detection substrate 6. The control unit changes the transmission direction of the transmission waves transmitted from the transmitting array antenna by changing the phase of the transmission signal supplied to each of the plurality of transmitting antenna elements.

[0100] The receiving array antenna has a plurality of receiving antenna elements arranged at regular intervals on the detection substrate 6. When the transmission waves transmitted from the transmitting array antenna are reflected by an object, each receiving antenna element of the receiving array antenna receives the reflected waves and outputs the received reflected waves as a received signal.

[0101] The control unit determines the direction from which the reflected wave is incident based on the phase of the received signal output by each receiving antenna element.

[0102] The detection board 6 is disposed inside the housing 100 on the rear side of the housing 100 (that is, on the depth side of the housing 100) so that the transmitting array antenna and the receiving array antenna face the optical window 200.

[0103] Specifically, the detection board 6 is installed inside the housing 100 so that a portion 100b of the outer wall that constitutes the housing 100 and that faces the optical window 200 is closer than the optical window 200.

[0104] [Seventh embodiment] A seventh embodiment of the present disclosure will be described below with reference to the drawings. In the seventh embodiment, only the parts that are different from the sixth embodiment will be described. The same reference numerals will be used to designate common components.

[0105] The distance measuring device 1 of the seventh embodiment differs from the sixth embodiment in that the arrangement of the detection board 6 is changed.

[0106] As shown in FIG. 11, the detection board 6 is arranged inside the housing 100 on the front side of the housing 100 (i.e., on the opening side of the housing 100) so that the transmitting array antenna and the receiving array antenna face the optical window 200.

[0107] Specifically, the detection board 6 is installed inside the housing 100 so that the detection board 6 is closer to the optical window 200 than a portion 100b of the outer wall that constitutes the housing 100 that faces the optical window 200.

[0108] In the distance measuring device 1 configured as above, the detection board 6 is installed near the optical window 200. Therefore, heat generated from the detection board 6 is easily transferred to the housing 100 on the optical window 200 side, and the transferred heat is easily cooled by receiving the wind generated by the vehicle traveling. Furthermore, since the optical window 200 is made of resin or glass, heat is not normally easily transferred thereto, but the provision of the metal mesh heater 50 makes it easier for heat to be transferred thereto. Therefore, the area that receives the wind is increased, and the heat generated from the detection board 6 is easily diffused. As a result, the distance measuring device 1 of the seventh embodiment can improve the heat dissipation efficiency of the detection board 6.

[0109] Although one embodiment of the present disclosure has been described above, the present disclosure is not limited to the above embodiment and can be implemented in various modifications.

[0110] [Variation 1] For example, in the second, third, and fourth embodiments, the metal mesh heater 50 is formed so that the mesh opening width changes depending on the position covering the opening 100a. However, the metal mesh heater 50 may be formed so that the line width of the metal wire 51 (hereinafter, metal width) changes depending on the position covering the opening 100a.

[0111] Specifically, the metal mesh heater 50 may be formed so that a passing metal width setting condition is met, in which the metal width in the light-transmitting region R1, which is the region in the opening 100a through which the transmitted wave and the reflected wave pass, is set to be shorter than the metal width in at least a portion of the region other than the light-transmitting region R1 in the opening 100a (i.e., the light-non-transmitting region R2).

[0112] The metal mesh heater 50 may also be formed so as to satisfy a lower metal width setting condition in which the metal width in the lower region R3 corresponding to the lower region of the opening 100a is set to be longer than the metal width in the region corresponding to the region above the lower region R3 of the opening 100a.

[0113] The metal mesh heater 50 may also be formed so that a left and right side metal width setting condition is met, in which the metal width in the right region R5 and left region R4 corresponding to the right and left regions of the opening 100a is set to be longer than the metal width in regions corresponding to regions other than the right region R5 and left region R4 of the opening 100a.

[0114] [Variation 2] In the above embodiment, the plurality of metal wires 51 are arranged diagonally to form the plurality of mesh openings 52. However, the arrangement of the plurality of metal wires 51 may be any arrangement that allows the formation of the plurality of mesh openings 52. For example, as shown in FIG. 12 , the plurality of metal wires 51 may be arranged horizontally and vertically.

[0115] In the above embodiments, multiple functions of one component may be realized by multiple components, or one function of one component may be realized by multiple components. Furthermore, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, part of the configuration of the above embodiments may be omitted. Furthermore, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments. [Technical idea disclosed in this specification] [Item 1] a transmitting unit (11) configured to transmit a transmission wave; a receiving unit (12) configured to receive a reflected wave generated when the transmitted wave is reflected by an object; a housing (100) that accommodates the transmitting unit and the receiving unit therein and has an opening (100a) formed therein for passing the transmitted wave and the reflected wave; a transmitting portion (200) formed of a material that transmits the transmitted wave and the reflected wave and that covers the opening; a heating section (50) that is formed in a mesh shape from metal and has a plurality of mesh openings (52), that is arranged to cover at least a part of the openings, and that generates heat by passing electricity through the metal to heat the transmission section; A distance measuring device (1) comprising:

[0116] [Item 2] The distance measuring device according to item 1, The width of the mesh opening is defined as the mesh opening width, A distance measuring device in which the mesh opening width of the plurality of mesh openings is longer than the wavelength of the transmission wave and shorter than the wavelength of an electromagnetic wave that becomes noise in the distance measuring device.

[0117] [Item 3] The distance measuring device according to item 1 or 2, A distance measuring device in which the heating section is formed so that the ratio of the area of ​​the metal that blocks the transmission wave to the area of ​​the transmission wave that passes through the transmission section is 10% or less.

[0118] [Item 4] The distance measuring device according to any one of items 1 to 3, The width of the mesh opening is defined as a mesh opening width, The width of the metal separating the adjacent mesh openings is defined as a metal width, The heating unit is formed so that at least one of the mesh opening width and the metal width changes depending on the position where the heating unit covers the opening.

[0119] [Item 5] Item 4. The distance measuring device according to item 4, The distance measuring device is mounted on a vehicle, The heating unit is a lower opening width setting condition that is set so that the mesh opening width in an opening lower region, which is a region below the opening, is shorter than the mesh opening width in an opening upper region, which is a region above the opening lower region; a lower metal width setting condition that is set so that the metal width in the lower region of the opening is longer than the metal width in the upper region of the opening; A distance measuring device configured to satisfy at least one of the above.

[0120] [Item 6] Item 4. The distance measuring device according to item 4, The distance measuring device is mounted on a vehicle, The heating unit is a left and right side opening width setting condition that is set so that the mesh opening width in left and right opening side regions, which are regions on the right and left sides of the opening, is shorter than the mesh opening width in a central opening region, which is a region of the opening other than the left and right opening side regions; left and right side metal width setting conditions are set so that the metal width in the left and right side regions of the opening is longer than the metal width in the central region of the opening; A distance measuring device configured to satisfy at least one of the above.

[0121] [Item 7] Item 4. The distance measuring device according to item 4, The heating unit is a pass-through opening width setting condition that is set so that the mesh opening width in a wave-passing region, which is a region in the opening through which the transmitted wave and the reflected wave pass, is longer than the mesh opening width in at least a part of the region of the opening other than the wave-passing region; a passing metal width setting condition that is set so that the metal width in the wave passing region is shorter than the metal width in at least a part of the region other than the wave passing region in the opening; A distance measuring device configured to satisfy at least one of the above.

[0122] [Item 8] The distance measuring device according to any one of items 1 to 7, The heating unit is on the metal separating adjacent mesh openings; a reflectance reduction treatment layer (53) that has been subjected to a reflectance reduction treatment for reducing reflection of the transmission wave and the reflected wave on the metal; a protective layer (54) for protecting the surface of the metal; a reflection suppression layer (55) for reducing reflection of the transmitted wave and the reflected wave; A distance measuring device comprising at least one of the above.

[0123] [Item 9] The distance measuring device according to any one of items 1 to 8, a detection board (6) on which the transmitting unit and the receiving unit are mounted, The detection board is installed inside the housing so that the transmission section is closer than a portion of an outer wall that constitutes the housing that faces the transmission section.

Claims

1. A distance measuring device, a transmitting unit (11) configured to transmit a transmission wave; a receiving unit (12) configured to receive a reflected wave generated when the transmitted wave is reflected by an object; a housing (100) that accommodates the transmitting unit and the receiving unit therein and has an opening (100a) formed therein for passing the transmitted wave and the reflected wave; a transmitting portion (200) formed of a material that transmits the transmitted wave and the reflected wave and that covers the opening; a heating section (50) that is provided with a plurality of mesh openings (52) formed in a mesh shape by a plurality of metal wires that block the transmission wave, that is arranged so as to cover at least a part of the openings, and that generates heat by passing current through the metal wires to heat the transmission section; Equipped with The width of the mesh opening is defined as the mesh opening width, the mesh opening width of the plurality of mesh openings is longer than the wavelength of the transmission wave and shorter than the wavelength of an electromagnetic wave that becomes noise in the distance measuring device; The width of the metal line separating the adjacent mesh openings is defined as a metal width, the heating unit is formed so that at least one of the mesh opening width and the metal width changes depending on the position where the heating unit covers the opening, The distance measuring device is mounted on a vehicle, The heating unit is a lower opening width setting condition that is set so that the mesh opening width in an opening lower region, which is a region below the opening, is shorter than the mesh opening width in an opening upper region, which is a region above the opening lower region; a lower metal width setting condition that is set so that the metal width in the lower region of the opening is longer than the metal width in the upper region of the opening; and The area below the opening is a distance measuring device (1) that is used to transmit the transmission wave downward from the direction of travel of the vehicle.

2. 2. The distance measuring device according to claim 1, A distance measuring device in which the heating portion is formed so that the ratio of the area of ​​the metal wire that blocks the transmission wave to the area of ​​the transmission wave that passes through the transmission portion is 10% or less.

3. 2. The distance measuring device according to claim 1, The heating unit is On the metal line separating the mesh openings adjacent to each other, a reflectance reduction treatment layer (53) on which a reflectance reduction treatment is performed to reduce reflection of the transmission wave and the reflected wave on the metal wire; a protective layer (54) for protecting the surface of the metal wire; a reflection suppression layer (55) for reducing reflection of the transmitted wave and the reflected wave; A distance measuring device comprising at least one of the above.

4. 2. The distance measuring device according to claim 1, a detection board (6) on which the transmitting unit and the receiving unit are mounted, The detection board is installed inside the housing so that the transmission section is closer than a portion of an outer wall that constitutes the housing that faces the transmission section.

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