Imaging device

Abstract

An imaging device (1) is provided with a housing (2) that houses an imaging element (3) and a main circuit board (6). A top plate (20) of the housing (2) is provided with a recess (200) having a recess outer wall surface (203a) that is recessed and a recess inner wall surface (203b) that protrudes to the inside of the housing (2), and a groove (201) that is formed on the outer wall surface of a top plate (20) and that communicates with the rear-side region of the recess (200). A heat-generating component (8) disposed on the main circuit board (6) is in thermal contact with the recess inner wall surface (203b), and the groove (201) extends from the rear-side region of the recess (200) to the side or rear of the housing (2), with the end of the groove in the extension direction being open.

Description

Imaging device

[0001] The present invention relates to an in-vehicle imaging device.

[0002] In recent years, with the aim of realizing a safe and comfortable motorized society, driver assistance systems have been increasingly installed in actual vehicles. Among these, development is progressing on systems that pursue safety, convenience, and comfort for drivers and passengers, such as collision mitigation braking systems that automatically stop the vehicle before a collision, automatic distance control systems that automatically track the vehicle ahead, lane departure prevention systems, and sign recognition. One such system is an external recognition system that recognizes vehicles, pedestrians, etc. and measures the distance to the target object.

[0003] Some electronic components installed inside an imaging device generate a large amount of heat. To improve the heat dissipation of these electronic components, a known configuration is to place the electronic components in thermal contact with the inner wall surface of the housing (see, for example, Patent Document 1). The housing area that is in thermal contact with the electronic components needs to be located close to the low-profile electronic components while maintaining a constant housing thickness to ensure dimensional accuracy. Therefore, the housing area is deformed toward the inside of the housing to be located close to the electronic components, and the outer wall surface of the housing becomes recessed relative to the surrounding outer wall surface of the housing.

[0004] JP 2008-193108 A

[0005] Incidentally, an imaging device, which is one type of input device for an external environment recognition system, must have a clear field of view in order to accurately recognize the external environment. In particular, in the case of a motorcycle or other vehicle that has an imaging device mounted on the exterior, raindrops are blown onto the imaging device from the front of the vehicle (the direction of travel) when traveling in the rain. As a result, raindrops tend to accumulate in the recesses of the imaging device's housing, causing corrosion and deterioration of the housing, leading to, for example, holes in the housing. In such cases, water droplets may enter the housing, potentially causing malfunctions in the circuit components.

[0006] An imaging device according to one aspect of the present invention is an in-vehicle imaging device that includes a housing that houses an imaging element and a circuit board, and at least the front side of the housing is exposed to the outside of the vehicle with the imaging direction being the forward side, and the top plate of the housing is provided with a recess having a recessed outer wall surface and a recess inner wall surface that protrudes inward of the housing, and a groove formed on the outer wall surface of the top plate that communicates with a rear side area of ​​the recess, and a heat-generating component arranged on the circuit board is in thermal contact with the inner wall surface of the recess, and the groove extends from the rear side area of ​​the recess to the side or rear of the housing, with the end of the groove in the extension direction being open.

[0007] According to the present invention, it is possible to improve the heat dissipation performance of an imaging device while preventing water droplets from accumulating, which can cause deterioration of the housing.

[0008] FIG. 1 is a perspective view showing an overview of an imaging device according to a first embodiment. FIG. 2 is a plan view showing the exterior of the imaging device. FIG. 3 is a diagram showing an example of mounting an imaging device on a motorcycle. FIG. 4 is a cross-sectional view taken along the line A1-A1 in FIG. 2. FIG. 5 is a diagram showing the exterior of an imaging device according to a comparative example. FIG. 6 is a cross-sectional view of an imaging device according to a comparative example. FIG. 7 is a diagram showing the exterior of an imaging device according to a first modified example. FIG. 8A is a cross-sectional view of the imaging device according to the first modified example, showing the A2-A2 cross-section of the imaging device taken along a plane S perpendicular to the x-axis shown in FIG. 7. FIG. 8B is a cross-sectional view of the imaging device according to the first modified example, showing the A3-A3 cross-section in FIG. 8A. FIG. 9 is a perspective view showing the exterior of an imaging device according to a second modified example. FIG. 10 is a cross-sectional view of the imaging device according to the second modified example. FIG. 11 is a diagram showing an imaging device according to a second embodiment of the present invention. FIG. 12 is a diagram showing a third modified example of an imaging device. FIG. 13 is a diagram showing a fourth modified example of an imaging device. FIG. 14 is a diagram showing another example of a heat dissipation fin. FIG. 15 is a diagram showing a fifth modified example of an imaging device. FIG. 16 is a diagram showing a sixth modification of the imaging device.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. Furthermore, in the following description, identical or similar elements and processes are given the same reference numerals, and duplicate explanations may be omitted. Note that the content described below merely shows an example of an embodiment of the present invention, and the present invention is not limited to the following embodiment, and can be implemented in various other forms.

[0010] First Embodiment An imaging device according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 6. FIGS. 1 and 2 are diagrams illustrating the exterior of imaging device 1. FIG. 1 is a perspective view of imaging device 1, and FIG. 2 is a plan view. Imaging device 1 is an on-vehicle imaging device that is installed on the body of a saddle-ride type vehicle such as a motorcycle, or on the exterior of a vehicle with a cabin (e.g., construction machinery, tractors, etc.). FIG. 3 is a diagram illustrating an example of imaging device 1 mounted on motorcycle 100. An opening 101 is formed on the front side of motorcycle 100, and imaging device 1 is mounted so as to capture an image of the area in front of the vehicle through opening 101 provided in the body. In FIG. 3, the fore-and-aft direction of the vehicle is defined as the x-axis, the lateral direction of the vehicle is defined as the y-axis, and the vertical direction of the vehicle is defined as the z-axis. The front of the vehicle is defined as the positive direction of the x-axis, the left side of the vehicle is defined as the positive direction of the y-axis, and the upward direction of the vehicle (vertically upward) is defined as the positive direction of the z-axis.

[0011] As shown in FIG. 1 , the imaging element, circuit components, and the like provided in the imaging device 1 are housed in a housing 2 composed of an upper cover 2 a, a lower cover 2 b, and a hood 2 c. As shown in FIG. 3 , the housing 2 is mounted on the motorcycle 100 so that the front-to-rear direction of the housing coincides with the front-to-rear direction of the vehicle. That is, the imaging device 1 is disposed on the vehicle so as to capture images of the area in front of the vehicle. Furthermore, if the imaging direction of the imaging device 1 is defined as the forward side, at least the front side of the housing 2 is exposed to the outside of the vehicle. Hereinafter, the positive x-axis side of the housing 2 will be referred to as the front side of the housing, the negative x-axis side as the rear side of the housing, the positive y-axis side as the left side of the housing, and the negative y-axis side as the right side of the housing.

[0012] An imaging window 21 made of a transparent material is fitted watertightly into an opening 210 formed on the front side of the housing of the hood 2c. A recess 200 recessed toward the inside of the housing is formed in the top plate 20 of the upper cover 2a. A groove 201 is formed on the left side of the housing of the recess 200. One end of the groove 201 communicates with the rear region of the recess 200. The groove 201 extends to the left side of the housing, and an end of the groove is open at the side surface of the upper cover 1a. In other words, the outlet of the groove 201 is exposed at the side surface of the upper cover 1a.

[0013] FIG. 4 is a cross-sectional view taken along the line A1-A1 in FIG. 2. The housing 2 of the imaging device 1 contains an imaging circuit board 4 with an imaging element 3 mounted thereon, a lens 5, a main circuit board 6, and other components. The imaging circuit board 4 is equipped with an imaging element such as a CCD sensor or a CMOS sensor, as well as electronic components (circuits) that drive the imaging element and perform predetermined processing on the electrical signals output from the imaging element. The main circuit board 6 is equipped with components that generate a large amount of heat during operation (hereinafter referred to as heat-generating components 8), such as a microcomputer that performs image processing and system control, and a signal processing element such as an FPGA (Field Programmable Gate Array) and an ASIC (Application Specific Integrated Circuit). In addition to the heat-generating components 8, other electronic components, such as a memory used for temporary data storage, are also mounted. A connector 7 is provided on the rear side of the housing of the main circuit board 6 to connect wiring to the vehicle. By housing the electronic components of the imaging device 1 within the housing 2 in this way, waterproofing is improved.

[0014] The upper cover 2a is made of a metal such as aluminum die-cast. The recess 200 has a bottom surface 203a, which is the outer wall surface of the recess formed by recessing the outer wall surface, and an inner wall surface 203b of the recess that protrudes into the housing 2. A heat-generating component 8 on the main circuit board 6 is in thermal contact with the inner wall surface 203b of the recess that protrudes into the housing via a thermally conductive member 9 such as a heat-dissipating gel. By thermally contacting the heat-generating component 8 with the metal upper cover 2a via the thermally conductive member 9, the heat dissipation of the heat-generating component 8 is improved. Furthermore, by making the plate thickness of the upper cover 2a constant, moldability is improved, the dimensional accuracy of the housing 2 is increased, and waterproofing is also improved.

[0015] 5 and 6 are diagrams showing a comparative example of this embodiment. Fig. 5 is a perspective view showing the appearance of an image pickup device 1A in the comparative example, and Fig. 6 is a cross-sectional view of the image pickup device 1A. The cross-sectional view of Fig. 6 shows the A1-A1 cross section of the image pickup device 1A, similar to Fig. 4. Below, we will explain the features of the image pickup device 1 of this embodiment in comparison with the image pickup device 1A.

[0016] In the imaging device 1A of the comparative example, the shape of the upper cover 2aA constituting the housing 2 is different from the shape of the above-described upper cover 2a. The recess 200A formed in the top plate 20 of the upper cover 2aA is an isolated recess, and the above-described groove 201 is not formed in the top plate 20. The function of the recess 200A is the same as the above-described recess 200, and heat-generating components 8 are in thermal contact with the inner wall surface of the recess 200A via the heat-conducting member 9, thereby improving heat dissipation performance.

[0017] Similar to the imaging device 1 described above, the imaging device 1A is an on-board imaging device that is installed on the body of a saddle-ride type vehicle such as a motorcycle, or on the exterior of a vehicle having a passenger compartment. For example, the imaging device 1A is installed on a motorcycle 100 in the configuration shown in FIG. 3 . Therefore, when traveling in the rain, rain blows from the front of the vehicle onto the front side of the housing of the imaging device 1A, and as shown in FIG. 6 , for example, water droplets 110 adhere to the hood 2c that is exposed from the vehicle. Some of the water droplets 110 that adhere to the hood 2c move on the upper cover 2aA toward the rear of the housing (the negative x-axis direction) due to wind caused by traveling, as shown by the dashed line, and accumulate in the rear end region of the recess 200A.

[0018] Water droplets 110 accumulated in the recess 200A can cause corrosion and deterioration of the upper cover 2aA, resulting in changes in the external dimensions. Such dimensional changes can cause gaps to form between the upper cover 2aA and the lower cover 2b and hood 2c, resulting in a decrease in waterproof performance. Furthermore, if the corrosion and deterioration of the upper cover 2aA due to water droplets progresses further, holes may form in the recess 200A. As a result, water droplets may enter the interior of the housing 2, causing malfunctions in electronic components and reducing reliability.

[0019] On the other hand, in the imaging device 1 of this embodiment, a groove 201 is formed in the top plate 20 as shown in FIG. 2 . The groove 201 is connected to the rear region of the recess 200 and extends from the rear region of the recess 200 toward the left side of the housing of the upper cover 2a, with the groove end (exhaust port) on the extended side open so as to be exposed on the side surface of the upper cover 2a. When the vehicle is traveling, wind blows from the front to the rear of the housing 2. A portion of the wind flowing along the top surface of the housing 2 hits the rear end side of the recess 200, changes direction left and right, and flows within the groove in the groove extension direction. As a result, water droplets 110 in the recess 200 are collected in the rear region of the recess 200 due to the influence of the wind, and the water droplets 110 that have accumulated in the rear region (see FIG. 2 ) pass through the groove 201 and fall from the top plate 20 as indicated by the dashed arrow. In this manner, in this embodiment, water droplets that have accumulated in the recess 200 are easily discharged from the recess 200 via the groove 201.

[0020] 1 and 2, the groove 201 extends from the rear region of the recess 200 to the left side of the housing, but it may also extend rearward as shown by the two-dot chain line. The end of the groove is open on the rear side surface of the housing 2, from which water droplets fall.

[0021] Furthermore, in motorcycles such as saddle-ride vehicles, a side stand is often used when the vehicle is stopped. As shown in Figures 1 and 2, by extending groove 201 from recess 200 toward the left side of the housing, the direction of tilt caused by the side stand (left side of the vehicle) and the extension direction of groove 201 are aligned. As a result, when the vehicle is stopped and the side stand is used, water droplets in recess 200 are reliably discharged through groove 201, preventing corrosion and deterioration due to water droplets remaining in recess 200.

[0022] In this embodiment, the top plate area facing the heat-generating component 8 is recessed toward the microcomputer to form a recess 200, and the recess inner wall surface 203b protruding into the inside of the housing is in thermal contact with the heat-generating component 8 via the thermally conductive member 9. Furthermore, the groove 201 for draining water droplets from the recess 200 is configured to communicate with a portion (rear region) of the recess 200, minimizing the extent to which the inner wall surface in the top plate area other than the recess 200 protrudes into the inside of the housing. Therefore, a sufficient height of space is formed between the main circuit board 6 and the top plate 20 in areas other than the recess 200 and the groove 201, making it easy to secure space for arranging tall electronic components, such as capacitors. This increases the degree of freedom in arranging electronic components on the main circuit board 6, enabling circuit design optimization and miniaturization.

[0023] It is preferable to form the corner region where the bottom surface of groove 201 intersects with the side surface of upper cover 2a and the region where the side surface of recess 200 intersects with bottom surface 203a into a rounded shape without any corners, or to form the groove cross section into a U-shape. By using such shapes, the surface tension of water droplets 110 is reduced, making it difficult for water droplets 110 to accumulate in the corner regions of recess 200 and groove 201. Furthermore, a rounded shape or a U-shape is preferable in terms of moldability when molding housing 2.

[0024] (Variation 1) FIGS. 7, 8A, and 8B are diagrams illustrating Variation 1 of the first embodiment. FIG. 7 is a perspective view showing the appearance of an image pickup device 1B in Variation 1. FIG. 8A is a diagram illustrating an A2-A2 cross section of the image pickup device 1B cut along a plane S (see FIG. 7) perpendicular to the x-axis, and FIG. 8B is a diagram illustrating an A3-A3 cross section of FIG. 8A. In Variation 1, the configuration of the recess 200B and groove 201B formed in the upper cover 2a differs from that of the first embodiment described above, but the other configurations are the same as those of the first embodiment. The different configurations will be described below.

[0025] In Figures 7, 8A, and 8B, the bottom surface 203a of the recess 200B (i.e., the outer wall surface of the recess) is inclined so that it is lower toward the rear and left sides of the housing. The bottom surface of the groove 201B is also inclined downward in the extension direction. Although not shown, the bottom surface 203a of the recess 200B may be inclined so that it is lower only toward the rear side of the housing, or the bottom surface of the groove 201B may also be inclined downward toward the rear side of the housing. In this way, by inclining the bottom surface 203a of the recess 200B and the bottom surface of the groove 201B downward toward the rear and left sides of the housing, water droplets within the recess 200B can be discharged by utilizing the effects of gravity in addition to the effect of wind while the vehicle is running. As a result, water droplets are more reliably prevented from accumulating in the recess 200B, preventing corrosion and deterioration of the housing 2.

[0026] (Modification 2) FIGS. 9 and 10 are diagrams illustrating Modification 2 of the first embodiment. In Modification 1 described above, groove 201B is provided on the left side of recess 200B, but in imaging device 1C of Modification 2, grooves 201C1 and 201C2 are provided on the left and right sides of recess 200B. FIG. 9 is a perspective view showing the appearance of imaging device 1C of Modification 2. FIG. 10 is an A4-A4 cross-sectional view of imaging device 1C taken along plane S (see FIG. 9) perpendicular to the x-axis. Image pickup device 1C of Modification 2 differs from Modification 1 in that two grooves 201C1 and 201C2 are provided, but the rest of the configuration is the same as that of Modification 1 described above. The different configurations are described below.

[0027] In Modification 2, groove 201C1 is provided on the left side of recess 200B, and groove 201C2 is provided on the right side of recess 200B. Groove 201C1 is connected to the rear region of recess 200B and extends from the rear region of recess 200B to the left side of the housing, with the end of the groove in the extension direction opening on the left side surface of upper cover 2a. In other words, the cross section of the groove is exposed on the left side surface of the housing of upper cover 2a, forming an outlet. The bottom surface 204a of groove 201C1 is a downwardly inclined surface inclined at an inclination angle θ1 in the extension direction (toward the left side of the housing). Meanwhile, groove 201C2 is connected to the rear region of recess 200B and extends from the rear region of recess 200B to the right side of the housing, with the end of the groove in the extension direction opening on the right side surface of upper cover 2a. The bottom surface 204b of the groove 201C2 is a downwardly inclined surface inclined at an inclination angle θ2 in the extension direction (toward the right side of the housing).

[0028] The tilt angles θ1 and θ2 are set such that θ2 > θ1. Furthermore, if the tilt angle θ3 is the angle of the vehicle's leftward tilt when the side stand is used while the vehicle is parked, it is preferable to set the tilt angle θ2 so that θ2 > θ3. For example, the tilt angle θ2 is set such that θ2 ≥ 10 degrees. The two-dot chain line in FIG. 10 indicates the orientation of the housing 2 when parked, with the housing 2 tilted to the left (left side of the housing) by an angle θ3. By setting the tilt angle θ2 so that θ2 > θ3, the bottom surface 204b of the groove 201C2 is inclined downward in the extension direction (to the right in the figure) relative to the horizontal plane even when the side stand is used. Therefore, even when the vehicle is parked in a tilted position due to the side stand, water droplets can be drained from the recess 200B by the groove 201C2.

[0029] On the other hand, the inclination angle θ1 of the groove 201C1 is such that the direction of tilt caused by the side stand and the extension direction of the groove 201C1 are the same. Therefore, as long as the side stand is tilted, water droplets can be discharged from the recess 200B regardless of the inclination angle. Therefore, by making the inclination angles θ1 and θ2 different and setting the inclination angle θ1 of the groove 201C1 smaller than the inclination angle θ2 of the groove 201C2 as described above, the height from the main circuit board 6 to the top panel 20 on the left side of the recess 200 can be ensured. As a result, the height restrictions on the board components that can be mounted on the main circuit board 6 can be alleviated, increasing the degree of freedom in circuit design and enabling optimization and miniaturization of the circuit, thereby reducing costs.

[0030] 1, when groove 201 is provided only on the left side of the housing of recess 200, if the vehicle is tilted to the right while traveling, the bottom surface of groove 201 is inclined upward with respect to the extension direction, and water droplets in recess 200 are not drained through groove 201. In Modification 2, even in such a case, water can be drained through groove 201C2 on the right side of the housing of recess 200B.

[0031] 10, the areas R1, R2, and R3 surrounded by dashed lines have sharp edges where two surfaces intersect, but it is preferable to make them smoothly rounded as described in the first embodiment. This reduces the surface tension of water droplets at the intersections of the two surfaces, preventing water droplets from easily accumulating.

[0032] Second Embodiment FIG. 11 is a diagram showing an imaging device 1D according to a second embodiment of the present invention. In the second embodiment, water droplets are effectively discharged from the recess by utilizing the flow of wind generated by traveling. The imaging device 1D differs from the imaging device 1 of the first embodiment described above in the configuration of the groove 201D, but the other configurations are the same as those of the first embodiment. The following describes the different configurations. FIG. 11 is a plan view of the imaging device 1D, with the left-right direction in the figure representing the front-rear direction of the housing. The top plate 20 of the upper cover 2a is formed with a recess 200 and a groove 201D that communicates with the rear region of the recess 200. The groove 201D extends from the rear region of the recess 200 diagonally rearward to the left of the upper cover 2a and opens onto the left side surface of the upper cover 2a.

[0033] By extending the groove 201D diagonally rearward from the recess 200 in this manner, the wind generated by the vehicle traveling is guided as indicated by the arrow 300. Therefore, the water droplets 110 in the recess 200 are guided into the groove 201D by the wind, and the water droplets 110 in the groove 201D are also guided in the extending direction, thereby more effectively discharging the water droplets 110. As a result, the accumulation of the water droplets 110 in the recess 200 can be more reliably prevented. In the example shown in FIG. 11 , the bottom surfaces of the recess 200 and the groove 201D are not inclined, but it is more preferable to make them inclined as in the first modification. Furthermore, as in the second modification, the grooves 201D may be formed on both the left and right sides of the recess 200.

[0034] (Variation 3) Fig. 12 is a diagram showing Variation 3 of the second embodiment. Fig. 12 is a plan view of an image pickup device 1E in Variation 3. The image pickup device 1E of Variation 3 differs from the first embodiment described above in the configuration of the recess 200E and grooves 201E1 and 201E2, but the other configurations are the same as those of the first embodiment. The different configurations will be described below. A convex portion 211 that protrudes toward the front side of the housing is formed near the center of the rear end of the recess 200E. In addition, a groove 201E1 is provided on the left side of the rear region of the recess 200E, and a groove 201E2 is provided on the right side of the rear region.

[0035] When the vehicle is traveling, the wind generated by the convex portion 211 is guided by the wind to the grooves 201E1 and 201E2, respectively, as indicated by arrows 301 and 302. As a result, water droplets accumulated in the rear region of the recess 200E are guided by the wind to the grooves 201E1 and 201E2, respectively, thereby improving the raindrop drainage function. In the example shown in FIG. 12, the planar shape of the convex portion 211 is a triangle with its apex at the front of the housing, but it may also be a convex portion with a flared shape with an R-shaped tip. Furthermore, the bottom surfaces of the recess 200E and the grooves 201E1 and 201E2 may be inclined as in the first modification described above, further improving the drainage effect.

[0036] (Variation 4) FIG. 13 is a diagram showing a variation of the imaging device 1E shown in FIG. 12 and is a perspective view showing the exterior of the imaging device 1F. The imaging device 1F of Variation 4 differs from the recess 200E of the imaging device 1E in the structure of the recess 200F, but is otherwise similar to the imaging device 1E. The following describes the different configuration. The recess 200F is provided with multiple heat dissipation fins 220 instead of the above-mentioned protrusion 211. The heat dissipation fins 220 erected on the bottom surface of the recess 200F are plate-shaped members extending in the front-to-rear direction of the housing. Note that a gap is provided between the rear end of the heat dissipation fin 220 and the rear-end side surface of the recess 200F, and grooves 201F1 and 201F2 communicate with this gap area.

[0037] When the vehicle is traveling, the airflow flows around the heat dissipation fins 220 in the recess 200F, improving the heat dissipation efficiency of the recess 200F, whose inner wall surface is in thermal contact with the heat-generating component 8. The improved heat dissipation efficiency enables the imaging device to be made more compact and have higher performance. Furthermore, water droplets that accumulate in the recess 200F are guided to the rear end region by the airflow flowing between the heat dissipation fins 220 and are then discharged via the grooves 201F1 and 201F2.

[0038] The heat dissipation fins 220 shown in FIG. 13 extend in the front-to-rear direction of the housing along the x-axis, but may have a shape as shown in FIG. 14 . In FIG. 14 , five heat dissipation fins 220a, 220b, and 220c are arranged in the recess 200F. The heat dissipation fin 220a has the same shape as the heat dissipation fin 220 shown in FIG. 12 and extends linearly in the front-to-rear direction of the housing along the x-axis. The heat dissipation fin 220b has the same shape as the heat dissipation fin 220a, but is tilted with respect to the x-axis so that its rear end is biased to the left or right. The heat dissipation fin 220c has a curved fin shape so that its rear end is biased to the left or right.

[0039] The airflow flowing rearward around the heat dissipation fins 220a, 220b, and 220c is influenced by the shape of the fins 220a, 220b, and 220c and flows as indicated by the dashed arrows. That is, the airflow flowing to the left of the fin 220a is guided toward the groove 201E1 on the left side of the housing, and the airflow flowing to the right of the fin 220a is guided toward the groove 201E2 on the right side of the housing. As a result, water droplets in the recess 200F are effectively guided by the airflow toward the groove 201E1 or 201E2.

[0040] The heat radiation effect from the heat radiation fins 220 due to the wind generated when the image pickup device 1F is running can be similarly achieved even if the image pickup device 1F is mounted upside down on the vehicle.

[0041] (Variation 5) Fig. 15 is a diagram showing Variation 5 of the second embodiment. Fig. 15 is a perspective view showing the appearance of an image pickup device 1G in Variation 5. In the image pickup device 1G of Variation 5, grooves 201E1 and 201E2 are arranged on both the left and right sides of the recess 200 in the upper cover 2a, and protrusions 230 are arranged on the side surfaces of the upper cover 2a where the cross sections of the groove end portions of the grooves 201E1 and 201E2 are exposed. The configuration other than the grooves 201E1 and 201E2 and the protrusions 230 is the same as that of the image pickup device 1 shown in Fig. 1, and the different configurations will be described below.

[0042] Each protrusion 230 is disposed on the front side of the housing at a position where the cross section of the groove end of grooves 201E1, 201E2 is exposed. Therefore, when wind generated while the vehicle is traveling splits into two flows above and below protrusion 230, a low-pressure region is formed behind protrusion 230. That is, the groove end portions, which are the outlets of grooves 201E1, 201E2, are disposed to face the low-pressure region behind protrusion 230. Therefore, water droplets in grooves 201E1, 201E2 are discharged to the side of the housing due to the pressure difference, thereby further improving the discharge effect of water droplets from grooves 201E1, 201E2.

[0043] 15, the grooves 201E1 and 201E2 and the protrusion 230 are disposed on both the left and right sides of the recess 200, but they may be disposed on only one side. In that case, it is preferable to provide them on the left side of the housing for the same reasons as in the case of FIG.

[0044] (Variation 6) Fig. 16 is a diagram showing Variation 6 of the second embodiment. Fig. 16 is a perspective view showing the appearance of an image pickup device 1H in Variation 6. In the image pickup device 1H of Variation 6, air guide passages 240 are provided instead of the protruding portion 230 of the image pickup device 1G shown in Fig. 15. The air guide passages 240 are provided on the left and right sides of the housing 2. The rest of the configuration is the same as that of the image pickup device 1G, and the following describes the different configurations.

[0045] Each groove 201E1, 201E2 extends from the rear region of the recess 200 toward the side of the housing 2, with the groove end in the extension direction being open on the side surface of the housing 2. In other words, the cross section of the groove end is exposed on the side surface of the housing 2. These cross sections are exposed inside the left and right air guide passages 240, respectively. The air guide passage 240 has an inlet 241 formed on the front side of the housing and an outlet 242 formed on the rear side of the housing. As shown in FIG. 3 , an opening 101 is formed on the front side of the motorcycle 100. The inlets 241 of the air guide passages 240 provided on the left and right sides of the image capture device 1H are positioned to face the opening 101.

[0046] When the vehicle is traveling, wind flows from the front of the vehicle into the inlets 241 of each air guide passage 240, flows through the air guide passages 240 toward the rear of the housing, and is discharged from the outlets 242. When the wind flows along the side of the housing in the air guide passages 240, the pressure on the side of the housing where the cross sections of the grooves 201E1 and 201E2 are exposed becomes lower than the pressure on the top surface of the upper cover 2a. As a result, water droplets in the grooves 201E1 and 201E2 are discharged into the air guide passages 240 from the cross sections of the groove ends due to the pressure difference, and are ultimately discharged to the outside of the air guide passages 240 from the outlets 242 by the wind.

[0047] In this way, in Modification 6, by providing the air guide passage 240 in which the groove ends are connected to the passage, it is possible to promote the discharge of water droplets from the grooves 201E1 and 201E2 by utilizing the pressure difference caused by the wind caused by running. The pressure drop at the side of the housing where the cross sections of the groove ends of the grooves 201E1 and 201E2 are exposed increases as the flow velocity of the wind flowing along the side of the housing. Therefore, in the air guide passage 240 shown in FIG. 16 , the flow path cross-sectional area of ​​the air guide passage 240 at the locations where the cross sections of the groove ends of the grooves 201E1 and 201E2 are exposed is made smaller than the area of ​​the inlet 241, so that the flow velocity of the wind caused by running is increased at the locations where the cross sections of the groove ends are exposed.

[0048] The above-described embodiment and modified examples provide the following advantageous effects. (1) As shown in Figures 1, 2, 4, etc., an in-vehicle imaging device 1 includes a housing 2 that houses an imaging element 3 and a main circuit board 6 (circuit board), and at least the front side of the housing 2 is exposed to the outside of the vehicle, with the imaging direction being the forward side. A top plate 20 of the housing 2 is provided with a recess 200 having a recessed bottom surface (outer wall surface of the recess) 203a and an inner wall surface 203b of the recess that protrudes inward from the housing 2, and a groove 201 formed in the outer wall surface of the top plate 20 and communicating with a rear region of the recess 200. A heat-generating component 8 arranged on the main circuit board 6 is in thermal contact with the inner wall surface 203b of the recess. The groove 201 extends from the rear region of the recess 200 to the side or rear of the housing 2, and an end of the groove in the extension direction is open. The groove 201 may extend from the end region of the recess 200 on the vehicle rear side toward the vehicle rear side of the housing 2, with the groove end in the extending direction being open.

[0049] Water droplets 110 that accumulate in the recess 200 collect in a rear region of the recess 200 due to the influence of wind while the vehicle is traveling. Because the groove 201 is connected to this rear region, water droplets 110 that collect in the rear region of the recess 200 flow from the recess 200 into the groove 201 due to the influence of wind while the vehicle is traveling or when the housing tilts to the left, and are then discharged from the open end of the groove. In this way, water droplets 110 that accumulate in the recess 200 are easily drained through the groove 201, thereby preventing corrosion and deterioration of the housing 2 due to the influence of accumulated water droplets. As a result, the heat dissipation performance of the imaging device 1 is improved, and the reliability of the imaging device 1 is improved by preventing water droplets from entering the interior of the housing 2 due to corrosion and deterioration.

[0050] (2) In (1) above, as shown in Figures 1 and 4, the recess 200 is preferably formed in the area of ​​the top plate 20 facing the heat-generating component 8. The recess 200 is formed so that the outer wall surface of the top plate 20 is recessed into the inside of the housing and the inner wall surface protrudes into the housing 2. Therefore, by forming the recess 200 in the area facing the heat-generating component 8, the extent to which the inner wall surface protrudes into the inside of the housing can be minimized. As a result, in the top plate area where the recess 200 is not formed, a storage space of sufficient height is secured, making it possible to easily secure space for arranging tall electronic components, such as capacitors.

[0051] (3) In (1) above, as shown in Fig. 1 and other figures, the groove 201 extends from the rear region of the recess 200 toward the left side of the housing 2. For example, in a two-wheeled vehicle such as a saddle-ride type vehicle, a side stand is used when the vehicle is stopped, and when the side stand is used and the vehicle leans to the left, the imaging device 1 also leans to the left. As a result, water droplets 110 that have accumulated in the recess 200 are drained through the groove 201, preventing corrosion and deterioration of the housing 2 due to water droplets 110 remaining in the recess 200.

[0052] (4) In (1) above, as shown in Figures 8A and 8B, the bottom surface 203a of the recess 200B (i.e., the outer wall surface of the recess) forms an inclined surface that slopes downward toward the rear of the housing 2 (i.e., downward toward the negative x-axis direction). By making the bottom surface 203a of the recess 200B an inclined surface that slopes downward toward the rear of the housing 2 in this way, water droplets in the recess 200B can be discharged by utilizing the effect of gravity in addition to the effect of wind caused by running. As a result, water droplets are more reliably prevented from accumulating in the recess 200B, and corrosion and deterioration of the housing 2 can be prevented.

[0053] (5) In the above (1), as shown in Figures 8A and 8B, the bottom surface 204a of the groove 201B forms an inclined surface that slopes downward in the extension direction of the groove 201B (i.e., downward in the positive y-axis direction). By sloping the bottom surface 204a of the groove 201B downward in the extension direction of the groove (toward the left side of the housing), water droplets in the groove 201B can be more effectively discharged by utilizing the effect of gravity.

[0054] (6) In (1) above, as shown in Figure 10, etc., the grooves provided in the top plate 20 have a first groove 201C1 whose bottom surface 204a (groove bottom surface) extends at a downward slope from the rear region of the recess 200B toward the left side of the housing 2, and a second groove 201C2 whose bottom surface 204b (groove bottom surface) extends at a downward slope from the rear region of the recess 200B toward the right side of the housing 2, and the inclination angle θ1 of the bottom surface 204a of groove 201C1 is different from the inclination angle θ2 of the bottom surface 204b of groove 201C2.

[0055] In this way, by making the bottom surfaces 204a, 204b of the left and right grooves 201C1, 201C2 inclined surfaces that slope downward toward the sides of the housing, the drainage effect of the grooves 201C1, 201C2 can be further enhanced. Furthermore, by varying the inclination angles θ1, θ2 so that the inclination angle of the groove extending in the direction of the housing tilt is larger depending on the tilt direction of the housing 2 when the vehicle is stopped, drainage is possible even when the vehicle is stopped. In this case, by setting the inclination angle θ1 of the groove 201C1 provided on the side of the vehicle tilted when stopped to be smaller than the inclination angle θ2 in consideration of the vehicle tilt angle θ3, it is possible to minimize the reduction in height space within the housing due to the provision of the groove 201C1.

[0056] (7) In (1) above, as shown in Fig. 15, the grooves 201E1 and 201E2 extend from the rear region of the recess 200 toward the side of the housing 2, with the groove ends in the extension direction opening to the side surface of the housing 2, and include a protruding portion 230 that protrudes from the side surface of the housing 2 forward of the groove ends on the side surface. Therefore, a low-pressure region is formed behind the protruding portion 230 by wind generated when the vehicle is traveling, and the effectiveness of discharging water droplets from the grooves 201E1 and 201E2 is further improved.

[0057] (8) In the above (1), as shown in Fig. 16, the grooves 201E1 and 201E2 extend from the rear region of the recess 200 toward the side of the housing 2, with the groove ends in the extension direction opening on the side surface of the housing 2, and include an air guide passage 240 that extends from the front side of the housing to the rear side of the housing 2 along the side surface of the housing 2 and with the groove ends communicating with each other. When the airflow from the vehicle flows along the side surface of the housing in the air guide passage 240, the pressure difference between the outside of the air guide passage in which the grooves 201E1 and 201E2 are provided and the inside of the air guide passage causes water droplets in the grooves 201E1 and 201E2 to be drawn into the air guide passage 240, thereby improving the drainage effect of the grooves 201E1 and 201E2.

[0058] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and the technical scope of the present invention is not intended to be limited to the specific configurations of the above embodiments. Furthermore, it is also possible to combine the configurations of the above-described embodiments with the configurations of the modified examples, or to combine the configurations of the modified examples with each other.

[0059] 1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H...imaging device, 2...housing, 2a...upper cover, 2b...lower cover, 2c...hood, 3...imaging element, 4...imaging circuit board, 5...lens, 6...main circuit board, 7...connector, 8...microcomputer (heat-generating component), 9...heat-conducting member, 20...top plate, 21...imaging window, 200, 200A, 200B, 200E, 20 0F...recess, 201, 201B, 201C1, 201C2, 201D, 201E1, 201E2, 201F1, 201F2...groove, 203a...bottom surface (outer wall surface of recess), 204a, 204b...bottom surfaces, 203b...inner wall surface of recess, 210...opening, 211...convex portion, 220, 220a, 220b, 220c...heat dissipation fins, 230...protrusion, 240...air guide passage

Claims

1. An in-vehicle imaging device comprising a housing that houses an imaging element and a circuit board, with at least the front side of the housing exposed to the outside of the vehicle with the imaging direction being the forward side, wherein the top plate of the housing is provided with a recess having a recessed outer wall surface and a recess inner wall surface that protrudes inward of the housing, and a groove formed on the outer wall surface of the top plate that communicates with a rear side area of ​​the recess, a heat-generating component arranged on the circuit board is in thermal contact with the recess inner wall surface, and the groove extends from the rear side area of ​​the recess to the side or rear of the housing, with the groove end in the extension direction being open.

2. An imaging device according to claim 1, wherein the recess is formed in an area of ​​the top plate facing the heat-generating component.

3. An imaging device according to claim 1, wherein the groove extends from the rear region of the recess toward the left side of the housing.

4. An imaging device according to claim 1, wherein the outer wall surface of the recess forms a sloped surface that slopes downward toward the rear of the housing.

5. An imaging device according to claim 1, wherein the bottom surface of the groove forms a sloped surface that slopes downward in the extension direction of the groove.

6. An imaging device according to claim 1, wherein the grooves comprise a first groove whose bottom surface extends from the rear region of the recess toward the left side of the housing at a downward slope, and a second groove whose bottom surface extends from the rear region of the recess toward the right side of the housing at a downward slope, and wherein the inclination angle of the groove bottom surface of the first groove is different from the inclination angle of the groove bottom surface of the second groove.

7. An imaging device according to claim 1, wherein the groove extends from the rear region of the recess toward the side of the housing, the groove end in the extension direction is open on the side surface of the housing, and the imaging device is provided with a protrusion that protrudes from the side surface of the housing further forward than the groove end on the side surface.

8. An imaging device according to claim 1, wherein the groove extends from the rear region of the recess toward the side of the housing, with the groove end in the extension direction being open on the side surface of the housing, and the imaging device is provided with an air guide passage that extends from the front side to the rear side of the housing along the side surface of the housing and with which the groove end is connected.

Images