Imaging device

Abstract

To provide an imaging device capable of reducing vibration to a sensor such as imaging element.SOLUTION: An imaging device includes: a housing having an open surface; a substrate fixed to the housing by a substrate support part; a cover covering the open surface of the housing; and an attenuation member connecting the cover and the housing and damping vibrations of the cover by elastic deformation. The attenuation member has a structure in which a part from the substrate to a cover side connection part is elastically deformed more easily than a part from the substrate to a housing side connection part.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an imaging device that is mounted on a vehicle and captures an image of an area ahead of the vehicle. [Background technology]

[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 decelerate before colliding with an obstacle, automatic vehicle distance control systems that automatically follow the vehicle in front while maintaining a roughly constant distance, lane departure prevention systems, and sign recognition systems. To realize such driver assistance systems, external recognition systems that can recognize vehicles, pedestrians, road surfaces, etc. and measure the distance to objects are required.

[0003] Here, we will explain a conventional imaging device (stereo camera), which is one type of input device for an external environment recognition system. Fig. 1A is an external perspective view of the conventional imaging device from above, and Fig. 1B is an external perspective view of the conventional imaging device from below. Note that this imaging device is attached to a vehicle so that the positive x-axis direction of the imaging device corresponds to the vehicle's traveling direction, the positive y-axis direction corresponds to the upward direction of the vehicle, and the positive z-axis direction corresponds to the rightward direction of the vehicle.

[0004] This imaging device includes a metal (e.g., aluminum die-cast) housing 1 having fins on the top surface and a space inside, a metal (e.g., aluminum plate) cover 10 covering the open surfaces (back and bottom) of the housing 1, and left and right imaging modules 2 (2L, 2R) that capture stereo images of the area in front of the vehicle. The cover 10 is fastened with a plurality of screws 10a to seal the housing 1, ensuring dustproofness, heat dissipation, and noise resistance for the imaging modules 2 and board 7 inside the housing. Although not shown, a connector for communication with a vehicle control device (ECU, etc.) is exposed from a part of the cover 10 (e.g., the back).

[0005] 2 is an enlarged cross-sectional view illustrating a method for fixing the substrate 7 inside the housing 1. As shown here, the substrate 7 is connected to the housing 1 with screws 8, but is not in contact with the cover 10. Summary of the Invention [Problem to be solved by the invention]

[0006] For an external environment recognition device to accurately recognize the external environment, it is necessary to ensure a clear field of view for the imaging device. However, if an imaging device with the above-described configuration is subjected to severe vibrations, such as when traveling on rough terrain, the imaging module 2 will vibrate significantly, degrading the quality of the captured image and potentially degrading the external environment recognition performance. Furthermore, if the circuit elements on the board 7 are repeatedly strained by the vibrations, this may cause breaks in the solder joints on the board 7. Furthermore, when the cover 10 is subjected to vibrations while traveling, vibration modes such as the cover primary bending vibration mode M1 (FIG. 3A) and the cover secondary bending vibration mode M2 ​​(FIG. 3B) occur. However, if the cover 10 is made thinner to reduce weight and cost, these vibration modes tend to occur at low frequencies, causing the cover 10 to vibrate like a speaker and generate noise. Additionally, low-frequency vibration modes of the cover 10 also pose a problem of increased resonance with the vibration modes of the housing 1.

[0007] As described above, conventional imaging devices require measures to reduce vibrations in the imaging module, the circuit board, and the cover to broaden the vibration mode frequency band, as well as measures to prevent resonance between the housing and the cover.

[0008] The present invention has been made in view of the above problems, and has an object to provide an imaging device that can reduce vibrations of the imaging module, the board, and the cover. [Means for solving the problem]

[0009] The present application includes multiple means for solving the above problem, and one example thereof is a structure comprising a housing having an open surface, a substrate fixed to the housing by a substrate support portion, a cover covering the open surface of the housing, and a damping member connecting the cover and the housing and damping vibration of the cover by elastic deformation, wherein the damping member is a structure in which the portion from the substrate to the cover-side connection portion is more susceptible to elastic deformation than the portion from the substrate to the housing-side connection portion. [Effects of the Invention]

[0010] According to the imaging device of the present invention, it is possible to reduce vibrations of the imaging device (particularly the cover, the board, and the imaging module). [Brief explanation of the drawings]

[0011] [Figure 1A] FIG. 10 is an external perspective view of a conventional imaging device viewed from above. [Figure 1B] FIG. 10 is a perspective view of the exterior of a conventional imaging device, seen from below. [Figure 2] 10A and 10B are enlarged cross-sectional views illustrating a conventional method for fixing a substrate of an imaging device. [Figure 3A] A diagram showing the primary bending vibration mode of the cover of a conventional imaging device. [Figure 3B] 10 is a diagram illustrating the secondary bending vibration mode of the cover of a conventional imaging device. [Figure 4] FIG. 1 is a perspective view of an imaging device according to a first embodiment. [Figure 5A] FIG. 2 is a cross-sectional view of the damping member of the first embodiment. [Figure 5B] FIG. 2 is a perspective view of a damping member according to the first embodiment. [Figure 5C] 10 is a modified example of the damping member of the first embodiment. [Figure 6] FIG. 3 is an explanatory diagram of a method for attaching the damping member according to the first embodiment. [Figure 7] FIG. 3 is an explanatory diagram of the arrangement of the damping member according to the first embodiment. [Figure 8A] FIG. 10 is a cross-sectional view of a damping member according to a second embodiment. [Figure 8B] FIG. 10 is a perspective view of a damping member according to a second embodiment. [Figure 9A]FIG. 10 is a perspective view of a damping member according to a second embodiment. [Figure 9B] FIG. 10 is a perspective view of a damping member according to a second embodiment. [Figure 9C] FIG. 10 is a cross-sectional view of a damping member according to a second embodiment. [Figure 10] FIG. 11 is a perspective view of a damping member according to a third embodiment. [Figure 11] FIG. 11 is a perspective view of a damping member according to a third embodiment. [Figure 12] FIG. 10 is a perspective view of a damping member according to a fourth embodiment. [Figure 13A] FIG. 10 is a cross-sectional view of a damping member according to a fifth embodiment. [Figure 13B] FIG. 10 is a perspective view of a damping member according to a fifth embodiment. [Figure 14A] FIG. 13 is a cross-sectional view of a damping member according to a sixth embodiment. [Figure 14B] FIG. 13 is a perspective view of a damping member according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the imaging device of the present invention will be described with reference to the drawings. Note that a duplicated description of points common to the above-mentioned conventional imaging device (FIGS. 1A and 1B) will be omitted. [Example]

[0013] First, an imaging device 100 according to a first embodiment of the present invention will be described with reference to Figures 4 to 7. Note that, although an example in which the imaging device 100 is a stereo camera will be described below, the imaging device 100 may also be a monocular camera.

[0014] As shown in the perspective view of Figure 4, the imaging device 100 of this embodiment includes a housing 1, a left imaging module 2L, a right imaging module 2R, a substrate 7 on which multiple circuit elements 6 are mounted, a damping member 12 that supports the substrate 7, and a cover 10 (not shown).

[0015] The left imaging module 2L includes a left imaging element 3L that captures images in front, a left imaging board 4L that has the left imaging element 3L mounted thereon, and a left lens 5L that is disposed in front of the left imaging element 3L. Similarly, the right imaging module 2R includes a right imaging element 3R that captures images in front, a right imaging board 4R that has the right imaging element 3R mounted thereon, and a right lens 5R that is disposed in front of the right imaging element 3R.

[0016] Circuit elements 6 (6a to 6c) are mounted on the substrate 7. The first circuit element 6a is a microcomputer or signal processing element that processes image signals, an FPGA (Field Programmable Gate Array), or the like, and is a circuit element that generates a large amount of heat and requires heat conduction to the housing 1, cover 10, or the like. The second circuit element 6b is a memory used for temporary data storage, and the third circuit element 6c is an element that performs various types of signal processing, such as an MPU (Micro Processing Unit). Note that the circuit elements 6 are not limited to the above elements.

[0017] In this type of imaging device (stereo camera), a pair of left and right imaging modules 2 captures stereo images of the area ahead of the vehicle. The image information from the pair of images is extracted, and the integrated circuit performs processing to determine the number of pixels where the feature points are displaced between the pair of images (parallax), thereby calculating distance. Therefore, when vibrations from the housing 1 or cover 10 of the imaging device are transmitted to the left and right imaging elements 3, differences in the vibrations occur in the images, resulting in differences in distance and speed, and thus reduced measurement accuracy. Furthermore, as imaging devices become more powerful, with wider angles of view, higher accuracy, and higher speeds, the tolerance for vibrational deviations has decreased, creating a need to reduce the vibration amplitude of the imaging device. Furthermore, when vibrations are transmitted to the circuit board 7, repeated strain is applied to the circuit elements 6 mounted on the board 7, potentially causing breaks in the solder joints. In particular, improving the performance of sensors to handle various environments, such as rough terrain, is expected to require increased external disturbances and a wider frequency band, increasing the need to reduce vibration amplitude.

[0018] Taking these issues into consideration, the imaging device 100 of this embodiment uses a damping member 12 instead of the screw 8 shown in Figure 2 that was used in conventional imaging devices, thereby making it possible to reduce the vibration amplitude of the housing 1, board 7, and cover 10.

[0019] <Structure of the damping member 12 of this embodiment> In the imaging device 100 of this embodiment, as shown in Fig. 4, four damping members 12 that perform both the function of supporting the board and the function of reducing vibrations are disposed between the housing 1 and the cover 10. The vibrations of the cover 10 are absorbed and damped by the elastic deformation of these damping members 12, and as a result, the vibration amplitude of the imaging module 2, board 7, and cover 10 is reduced. The structure and function of the damping members 12 will be described in detail below.

[0020] In this embodiment, the damping member 12 is made of an elastic material such as silicone rubber, with high rigidity at the portion connecting the substrate 7 to the housing 1 and low rigidity at the portion connecting the substrate 7 to the cover 10. Therefore, the elastic deformation of the damping member 12 is small on the housing side and large on the cover side. These characteristics allow the substrate 7 to be rigidly attached to the highly rigid housing 1 to prevent wire breakage on the substrate 7 due to vibration, thereby increasing the frequency of the vibration mode of the substrate 7. In contrast, the vibration mode of the cover 10 is likely to occur at low frequencies, so the elastic deformation of the damping member 12 reduces the vibration amplitude.

[0021] Fig. 5A is a cross-sectional view of the damping member 12 in the imaging device 100, and Fig. 5B is a perspective view of the damping member 12. As shown in these figures, the damping member 12 of this embodiment has a substrate support portion 12a, an insertion portion 12b, a deformation portion 12c, and a hollow portion 12d.

[0022] The board support portion 12a is a portion for supporting the board 7, and is, for example, a double flange provided so as to sandwich the board 7 from above and below. A possible method for attaching such a board support portion 12a to the board 7 is the method shown in Figure 6. That is, if the board 7 has a configuration in which a notch 7a is provided at the end, the damping member 12 can be attached to the board 7 by inserting the board support portion 12a from the side of the notch 7a.

[0023] The insertion portion 12b is a portion for fixing the damping member 12 to the housing 1, and is, for example, a bush that is inserted while elastically deforming into the through-hole 1b of the substrate fixing portion 1a of the housing 1. As shown in Fig. 5A, the tip of the insertion portion 12b has a structure that expands in the radial direction so as to prevent dust and the like from entering the imaging device 100.

[0024] FIG. 5C is a perspective view illustrating another tip shape of the insertion portion 12b. The insertion portion 12b in FIG. 5B has a truncated cone-shaped tip. However, a slit may be formed in the side of the truncated cone-shaped tip, as in insertion portion 12b1, or multiple notches may be formed in the side of the truncated cone-shaped tip, as in insertion portion 12b2. In either case, the insertion portion 12b is more easily deformed than the insertion portion 12b in FIG. 5B, thereby improving the ease of assembly for fixing the damping member 12 to the housing 1. When using the insertion portion 12b2, it is desirable to provide a recess (indicated by a dashed line in the lower right drawing of FIG. 5C) on the outer surface of the housing 1 that matches the shape of the insertion portion 12b2 in a top view. By doing so, the insertion portion 12b2 can be fitted into the recess by rotating it in the direction of the arrow, preventing the damping member 12 from rotating.

[0025] The deforming portion 12c connects the substrate 7 and the cover 10 and is a portion that elastically deforms due to vibrations transmitted to the imaging device 100 during travel. The deforming portion 12c has a hollow portion 12d formed therein to reduce its rigidity and facilitate elastic deformation. As shown in FIGS. 5A and 5B, the deforming portion 12c also has a stepped structure in which annular flat plate portions and perfect cylinders are alternately stacked, thereby reducing its rigidity and promoting elastic deformation. While FIG. 5A illustrates the deforming portion 12c with a stepped structure in which two perfect cylinders are stacked one on top of the other, a stepped structure in which more perfect cylinders are stacked may be used if it is desired to further promote elastic deformation.

[0026] Furthermore, in order to make the rigidity of deformation portion 12c lower than that of insertion portion 12b, the dimensions of damping member 12 are designed as follows: That is, the plate thickness ta of deformation portion 12c is made thinner than the plate thickness tb of insertion portion 12b, and the distance la between substrate 7 and cover 10 is made longer than the distance lb between substrate 7 and housing 1. Due to these dimensional features, in damping member 12, the elastic deformation between substrate 7 and cover 10 is greater than the elastic deformation between housing 1 and substrate 7.

[0027] 5B, the damping member 12 of this embodiment has a shape that is point-symmetrical with respect to the central axis (the dashed-dotted line in the figure), and therefore has a structure that is easy to assemble because there is no need to consider the circumferential orientation when attaching the damping member 12 to the housing 1. Furthermore, a protrusion may be provided on the inner surface of the cover 10 and used for positioning when contacting the damping member 12.

[0028] <Installation position of damping member 12> Here, the arrangement of the damping member 12 relative to the cover 10 will be described with reference to Fig. 7. As shown in Fig. 7, considering the multiple vibration modes of the cover 10 (primary bending vibration mode, secondary bending vibration mode, tertiary bending vibration mode, etc.), it is desirable to arrange the damping member 12 in a location where the mode amplitude is large so that the vibration amplitude can be reduced in each vibration mode.

[0029] Therefore, in this embodiment, when the length of the cover 10 in the longitudinal direction (z-axis direction) is L, the damping member 12 is disposed at a position between L / 6 and L / 3 from the longitudinal end face of the cover 10. By disposing the damping member 12 in this manner, the vibration amplitude of the cover 10 can be effectively reduced.

[0030] <Effects of this Example> As described above, connecting the housing 1 and the cover 10 with the damping member 12 and making the cover side of the damping member 12 less rigid than the housing side reduces the vibration amplitude of the cover 10. This also blocks vibration between the cover 10 and the housing 1, preventing resonance and reducing the vibration amplitude of the left and right image sensors 3. Reducing the vibration amplitude also suppresses vibration in the captured image, allowing for highly accurate measurement of the object's position and velocity. This also reduces repeated strain on the circuit board 7, preventing breaks in the solder joints on the circuit board 7. Furthermore, reducing the vibration amplitude of the cover 10 also reduces noise generated by the cover 10 acting as a vibrator. Furthermore, since the damping member 12 also serves as a circuit board support, the number of screws previously required to secure the circuit board 7 can be reduced, thereby reducing the number of parts in the imaging device. As a result, a high-performance, highly reliable imaging device 100 can be manufactured at low cost. [Example]

[0031] An imaging device according to a second embodiment of the present invention will be described with reference to Figures 8A and 8B and 9A to 9C. In this embodiment, the shape of the deforming portion of the damping member is different from that of the deforming portion 12c (Figures 5A and 5B) of the first embodiment, which has a stepped structure in which circular annular flat plate portions and circular cylinders are alternately stacked, but other structures are the same as those of the first embodiment, and therefore a duplicated description of the commonalities with the first embodiment will be omitted.

[0032] The damping member 13 of this embodiment, shown in the cross-sectional view of Figure 8A and the oblique view of Figure 8B, has a deforming portion 13a with a sloped structure in which a true annular flat plate portion and a true truncated cone side surface are laminated, instead of the deforming portion 12c of Example 1, and this sloped structure promotes elastic deformation.

[0033] 9A shows a perspective view of a damping member 14 of this embodiment, which has a stepped structure in which a regular polygonal annular flat plate and a regular polygonal cylinder are stacked instead of the deforming portion 12c of Example 1. This stepped structure promotes elastic deformation. Similarly, the perspective view of FIG. 9B shows a perspective view of a damping member 15 of this embodiment, which has a sloped structure in which a regular polygonal annular flat plate and a regular polygonal truncated pyramid side are stacked instead of the deforming portion 12c of Example 1. This sloped structure promotes elastic deformation.

[0034] Furthermore, the deforming portion 16a of the damping member 16 shown in the cross-sectional view of Figure 9C replaces the deforming portion 12c of Example 1, and has a part of the step structure (for example, a flat portion approximately parallel to the cover 10) made thinner than other parts, thereby promoting elastic deformation in the thinner part.

[0035] As described above, the imaging device 100 of this embodiment can achieve the following effect in addition to the effect of embodiment 1. That is, according to this embodiment, in which the deforming portion has a rectangular shape when viewed from above, or in which the deforming portion is intentionally provided with a portion that is weaker in rigidity than other portions, the deformation direction of the damping member is limited compared to embodiment 1, in which the deforming portion is annular when viewed from above and has a uniform thickness, and therefore it is possible to more easily design a damping member shaped to damp vibrations of the cover 10. [Example]

[0036] An imaging device according to a third embodiment of the present invention will be described with reference to Figures 10 and 11. Note that a duplicated description of points common to the above-mentioned embodiments will be omitted.

[0037] The damping member 17 of this embodiment shown in the perspective view of Fig. 10 has a deforming portion 17a with a stepped structure in which a polygonal ring-shaped (e.g., rectangular ring) flat plate with a different aspect ratio and a polygonal cylinder are overlapped, instead of the deforming portion 12c of Example 1. This stepped structure promotes elastic deformation. Similarly, the damping member 18 of this embodiment shown in the perspective view of Fig. 11 has a deforming portion 18a with a sloped structure in which a circular ring-shaped (e.g., elliptical ring) flat plate with a different aspect ratio and a truncated cone side are overlapped, instead of the deforming portion 12c of Example 1. This sloped structure promotes elastic deformation.

[0038] As shown in both figures, when the aspect ratios of the damping members 17, 18 are different, if the damping members are installed so that their longitudinal direction coincides with the longitudinal direction of the cover, even if the installation position of the damping members is slightly deviated from the reference position, the damping members will largely include an area (positions L / 6 to L / 3 from the longitudinal end face of the cover (see Figure 7)) where vibration amplitude can be reduced in multiple vibration modes of the cover 10, and therefore the vibration of the cover 10 can be appropriately reduced even if there are manufacturing variations or assembly variations in each damping member. [Example]

[0039] An imaging device according to a fourth embodiment of the present invention will be described with reference to Fig. 12. Note that a duplicated description of points common to the above embodiments will be omitted.

[0040] The damping member 19 of this embodiment, shown in the perspective view of Figure 12, is a further improvement over the deforming portion 17a of Example 3 (Figure 10), and is provided with deforming portions 19a that are divided circumferentially by slits (notches) extending in the longitudinal direction of the deforming portion. By dividing the deforming portion 19a in this way, a direction in which the deforming portion 19a is less likely to bend (the slit direction) and a direction in which it is more likely to bend (the direction perpendicular to the slits) are created, resulting in a structure that makes it easy to control elastic deformation by managing the shape, such as the plate thickness. Note that the position and number of slits are not limited to those exemplified in Figure 12, and any slits may be provided depending on the required specifications. [Example]

[0041] An imaging device according to a fifth embodiment of the present invention will be described with reference to Figures 13A and 13B. Note that a duplicated description of points common to the above embodiments will be omitted.

[0042] 13A and 13B, the damping member 20 of this embodiment is provided with an attachment structure 20a at the cover-side end of the deforming portion 12c for attaching the damping member 20 to the opening of the cover 10A. This attachment structure 20a allows the damping member 20 to be securely connected to the cover 10A, and can more effectively reduce vibration of the cover 10A. If the attachment structure 20a of the damping member 20 is a double-flange structure, making the diameter of the flange on the outer surface of the cover smaller than the diameter of the flange on the inner surface of the cover makes it easier to attach the damping member 20 to the cover 10A. [Example]

[0043] An imaging device according to a sixth embodiment of the present invention will be described with reference to Figures 14A and 14B. Note that a duplicated description of points common to the fifth embodiment will be omitted.

[0044] The damping member 21 of this embodiment shown in Figures 14A and 14B is a further improvement of the mounting structure 20a of Example 5, in which a two-part mounting structure 21a is inserted and fixed into holes 11 provided in two places on the cover 10B, thereby sealing the hollow portion 12d.

[0045] According to this embodiment, not only can the same effects as those of the fifth embodiment be obtained, but also the hollow portion 12d in a sealed state functions as an air damper, thereby further reducing the vibration amplitude of the cover 10B.

[0046] The present invention is not limited to the above-described embodiments, and includes various modifications and combinations within the scope of the gist of the present invention. Furthermore, the present invention is not limited to those having all of the configurations described in the above-described embodiments, and includes those in which some of the configurations are omitted. [Explanation of symbols]

[0047] 100...imaging device 1...Housing 1a...Board fixing part 1b...Through hole 2...Image capture module 3...Image sensor 4...Image board 5...Lens 6...Circuit element 6a...First circuit element 6b...Second circuit element 6c...Third circuit element 7...Substrate 7a…Notch part 8...Screw 10, 10A, 10B...Cover 11...hole 12...Damping member of Example 1 12a...Board support part 12b...insertion part 12c...Deformed section 12d...Hollow part 13 to 16...Damping member of Example 2 17, 18...Damping member of Example 3 19...Damping member of Example 4 13a to 19a...Elastic deformation portion 20...Damping member of Example 5 20a...Installation structure 21...Damping member of Example 6 21a...Mounting structure

Claims

1. a housing having an open surface, a substrate fixed to the housing by a substrate support part, a cover covering the open surface of the housing, and a damping member which is an elastic body having high rigidity at a portion connecting the substrate to the housing and low rigidity at a portion connecting the substrate to the cover, and which damps vibration of the cover by elastic deformation; The imaging device, wherein the damping member has a structure in which a portion from the substrate to the cover-side connection portion is more likely to elastically deform than a portion from the substrate to the case-side connection portion.

2. 2. The imaging device according to claim 1, The imaging device is characterized in that the attenuation member is provided at a location where the substrate is fixed by the substrate support portion.

3. 2. The imaging device according to claim 1, The imaging device, wherein the attenuation member is integral with the substrate support portion.

4. 2. The imaging device according to claim 1, The imaging device, wherein the attenuation member has a hollow structure in a region from the substrate to the cover-side connecting portion.

5. 2. The imaging device according to claim 1, 10. The imaging device according to claim 9, wherein the distance from the substrate to the cover of the attenuation member is longer than the distance from the substrate to the housing.

6. 2. The imaging device according to claim 1, The imaging device is characterized in that the attenuation member has a structure in which cylindrical bodies of different diameters are stacked on the cover-side connecting portion.

7. 2. The imaging device according to claim 1, The imaging device, wherein the attenuation member has a cover-side connecting portion that is long in the longitudinal direction of the cover.

8. 2. The imaging device according to claim 1, The imaging device is characterized in that the damping member is attached to the housing with a bushing structure.

9. 9. The imaging device according to claim 8, The imaging device is characterized in that the damping member is attached to the cover with a double flange structure.

10. a housing having an open surface, a substrate fixed to the housing by a substrate support part, a cover covering the open surface of the housing, and a damping member which is an elastic body having high rigidity at a portion connecting the substrate to the housing and low rigidity at a portion connecting the substrate to the cover, and which damps vibration of the cover by elastic deformation; The imaging device, wherein the damping member has a lower rigidity in a portion from the substrate to the cover-side connecting portion than in a portion from the substrate to the case-side connecting portion.

Images