JP7548786B2 - Camera equipment - Google Patents

Description

The present invention relates to a camera device that suppresses condensation on optical components.

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

A camera device, which is one type of input device for an external recognition system, must have a clear field of view in order to accurately recognize the outside world. However, if the camera device is installed on the inside of the windshield, the temperature difference between the inside and outside of the car that occurs when it is cold can cause condensation and clouding on the optical components of the camera device.

Patent Document 1 is known as a conventional technique for improving condensation on a camera device. For example, the abstract of Patent Document 1 discloses a camera device that "provides a camera device that can easily remove water droplets and ice that have adhered to the lens while keeping costs down," and that "includes a lens 13 with a hydrophilic coating on its surface 13b, a lens barrel 12 that supports the lens 13, and a substrate 22 to which a heating element 25 is attached. The lens barrel 12 is made of metal or a resin that has thermal conductivity, and the heating element 25 is connected to the lens barrel 12 via an adhesive 26. The heat generated by the heating element 25 is transferred to the lens 13 via the lens barrel 12, and the lens 13 itself is heated."

JP 2018-205606 A

However, as shown in Figures 1 and 3 of Patent Document 1, the camera device uses a lens barrel that has a large surface area and is exposed to the outside air to transfer heat from the heating element to the lens. As a result, a high percentage of the heat from the heating element is dissipated into the outside air as it travels through the lens barrel, and sufficient heat cannot be transferred to the lens, making the structure insufficient for preventing condensation on the lens (optical component).

The present invention was made in consideration of the above problems, and aims to provide a camera device that can improve the heat transfer efficiency from heat-generating components to optical components and suppress condensation on the optical components.

This specification includes multiple means for solving the above problems, and one example is a camera device that includes a camera module having a lens and an image sensor, a housing that holds the camera module so that the lens protrudes from the front of the housing, and a lens cover that covers the lens so that optical components are positioned in the optical axis direction of the lens, the housing having a protrusion that protrudes forward from the periphery of the lens, and the tip of the protrusion is thermally connected to the optical components.

The camera device of the present invention can improve the efficiency of heat transfer from heat-generating components to optical components, and can suppress condensation on the optical components.

FIG. 1 is a perspective external view of a camera device 101 according to a first embodiment. FIG. 2 is a cross-sectional view of the camera device 101 according to the first embodiment. FIG. 1 is a perspective see-through view of a camera device 101 according to a first embodiment. FIG. 2 is a cross-sectional view of a camera device 100 of a comparative example. FIG. 11 is a cross-sectional view of a camera device 102 according to a second embodiment. FIG. 11 is a perspective external view of a camera device 103 according to a third embodiment. FIG. 11 is a cross-sectional view of a camera device 104 according to a fourth embodiment. FIG. 13 is a perspective external view of a camera device 105 according to a fifth embodiment. FIG. 13 is a perspective external view of a camera device 106 according to a sixth embodiment. FIG. 13 is a perspective external view of a camera device 107 according to a seventh embodiment.

Below, an embodiment of the camera device of the present invention will be described with reference to the drawings. Note that, in the following, components with the same reference numerals have the same functions, and unless otherwise specified, duplicated explanations will be omitted. Also, to clarify the explanation of the position and orientation of each part, orthogonal coordinate axes consisting of the x-axis, y-axis, and z-axis are shown in the necessary drawings.

First, a camera device 101 according to a first embodiment of the present invention will be described with reference to Figures 1 to 4. In this embodiment, the front-to-rear direction of the camera device 101 is defined as the x-axis, the up-down direction as the y-axis, and the left-to-right direction as the z-axis, and the camera device 101 is installed on the inner surface of the vehicle's windshield 20 with the positive direction of the x-axis facing forward of the vehicle, the positive direction of the y-axis facing upward of the vehicle, and the positive direction of the z-axis facing to the right of the vehicle.

<Overall Configuration of Camera Device 101 of the Present Embodiment>
FIG. 1 is an external perspective view of a camera device 101 of this embodiment. As shown here, the camera device 101 of this embodiment is a stereo camera in which a pair of left and right lenses 4 protrude from the front side of a housing 1a. The rear side of the housing 1a is covered with a housing cover 11, and an enclosed space for accommodating a camera module 6 and a camera circuit board 10 described later is formed between the housing 1a and the housing cover 11. In addition, on the front side of the housing 1a, a plurality of convex parts 14 protrude forward from the periphery of the left and right lenses 4, and a number of heat dissipation fins are provided in the center part sandwiched between the left and right lenses 4. Furthermore, on the front side of the housing 1a, a pair of left and right lens covers 12 are attached so as to cover each lens 4. Note that FIG. 1 illustrates a structure in which two rectangular column-shaped convex parts 14 are provided near each lens 4, but the number and shape of the convex parts 14 are not limited to this example. For example, a structure in which two cylindrical convex parts 14 are provided near each lens 4, or a structure in which one plate-shaped convex part 14 is provided may be used.

A polarizing plate 13 is fitted into the front surface of each lens cover 12, so that light that passes through the polarizing plate 13 is incident on each lens 4. By using the polarizing plate 13, the camera device 101 of this embodiment can improve visibility regardless of the surrounding optical environment. The polarizing plate 13 may be in the form of a plate or a film, and the lens cover 12 may be fitted with another optical component other than the polarizing plate 13, such as a protective plate.

In addition, in FIG. 1, a stereo camera incorporating a pair of left and right camera modules 6 is illustrated as an example of the camera device 101, but the camera device 101 of this embodiment may be a mono camera incorporating a single camera module 6.

Figure 2 is a cross-sectional view of the camera device 101 taken along line A-A in Figure 1, with the convex portion 14 of the present invention hatched. As shown here, the lens 4, together with the image sensor 2 that converts light into an electrical signal, the image sensor circuit board 3 on which the image sensor 2 is mounted, and the camera holder 5 that holds both the image sensor circuit board 3 and the lens 4, constitute the camera module 6. This camera module 6 is housed in an enclosed space within the housing 1a together with the camera circuit board 10. As shown in the figure, the convex portion 14 that protrudes forward from the housing 1a is in contact with the inner surface of the polarizing plate 13 of the lens cover 12, so that heat generated by the camera module 6 and the camera circuit board 10 is transferred to the polarizing plate 13 via the housing 1a and the convex portion 14 that cover them.

Figure 3 is a perspective view of the camera device 101. As shown here, multiple circuit elements are mounted on the camera circuit board 10. The first circuit element 7 is a microcomputer, signal processing element, FPGA (Field Programmable Gate Array), etc. that processes the image signal output by the imaging element 2, and is a circuit element that generates a large amount of heat and needs to be cooled by dissipating heat to the housing 1a or the housing cover 11. The second circuit element 8 is a memory used to temporarily store data used by the first circuit element 7, and the third circuit element 9 is an element that performs various signal processing, such as an MPU (Micro Processing Unit). Note that the circuit elements mounted on the camera circuit board 10 are not limited to the above-mentioned elements.

In this embodiment, the housing 1a and the housing cover 11 are metal parts such as aluminum die-cast. As a result, the camera module 6 and the camera circuit board 10 are surrounded by metal, ensuring dustproofness and providing measures against electromagnetic fields and heat dissipation. Note that the protrusion 14 in this embodiment is integrally molded with the housing 1a as aluminum die-cast, but it may be a structure in which a separately manufactured metal or resin protrusion 14 with high thermal conductivity is attached to the aluminum die-cast housing 1a after the fact. In addition, the vehicle control device (ECU, etc.) and the camera device 101 are electrically connected by wiring the electrical connectors of both devices through an opening in the housing 1a (not shown).

Here, in a camera device 101 (stereo camera) equipped with a pair of left and right camera modules 6, feature points common to both images are extracted from a pair of image information capturing the forward view, and an integrated circuit performs processing to determine the number of pixels (parallax) by which the positions of the feature points are shifted between the pair of images, and calculates the distance to a preceding vehicle, etc. Therefore, if water droplets or cloudiness occur due to condensation or the like in front of the camera device 101, in other words on the polarizing plate 13, which is an optical component in front of the lens 4, this will interfere with recognition of the outside world and degrade the functionality of the camera device 101.

<Camera device 100 of comparative example>
Before explaining the effect of the protrusions 14 of this embodiment, the reason why condensation is likely to occur in the camera device 100 of the comparative example that does not have the protrusions 14 will be described with reference to the cross-sectional view of FIG.

Figure 4 is a cross-sectional view of a camera device 100 of a comparative example. As shown here, the camera device 100 of the comparative example is installed on the inner surface of the windshield 20 of a vehicle, and a lens cover 12 with a polarizing plate 13 fitted in it is attached in front of the lens 4 (in the imaging direction). In a low-temperature environment, the temperature of the outside air 21 outside the windshield 20 is also low, so when the camera device 100 is driven and the temperature of the housing 1 rises, a temperature difference occurs in front of and behind the polarizing plate 13, and water droplets and clouding occur on the high-temperature side of the polarizing plate 13 due to condensation. This phenomenon does not only occur at low temperatures, but condensation may also occur even at high temperatures due to the relationship between temperature, humidity, and the amount of saturated water vapor. If water droplets or clouding due to condensation occurs in front of the camera device 100, in other words, on the polarizing plate 13, which is an optical component in front of the lens 4, due to any of the phenomena, accurate recognition of the outside world is hindered, and as a result, there is a problem that the function of the driver assistance system using the camera device 100 is deteriorated.

<Effects of the protrusions 14 of this embodiment>
To solve this problem, the camera device 101 of this embodiment is structured so that the heat generated by the camera circuit board 10 and the image pickup element circuit board 3 in the housing 1a is transferred to the polarizing plate 13 through the housing 1a and the protruding portion 14 by bringing the polarizing plate 13 into contact with the protruding portion 14 extending forward from the housing 1a, as shown in Figs. 1 to 3. This structure can reduce the temperature difference between the front and back of the polarizing plate 13, thereby suppressing condensation on the polarizing plate 13. Alternatively, the conditions (environment) under which the polarizing plate 13 does not condense can be strengthened by increasing the temperature of the polarizing plate 13 and increasing the amount of saturated water vapor.

In addition, in the camera device 101 of this embodiment, in order to increase the heat transfer efficiency of the convex portion 14, the lens cover 12 is arranged to cover the periphery and isolate the convex portion 14 from the outside air so as to suppress heat dissipation from the convex portion 14 to the air. Furthermore, in the camera device 101 of this embodiment, in order to increase the heat transfer efficiency of the convex portion 14 by suppressing heat dissipation from the convex portion 14 to anything other than the polarizing plate 13, a gap is provided so that the convex portion 14 does not come into direct contact with the parts of the lens cover 12 other than the polarizing plate 13. With these structures, the convex portion 14 of this embodiment can efficiently transfer heat from the housing 1a, which uses the camera module 6 and the camera circuit board 10 as heat sources, to the polarizing plate 13, and the allowable environmental temperature of the camera device 101 can be expanded.

As described above, the camera device 101 of this embodiment is structured so that heat from the camera module 6 and camera circuit board 10 is transferred to the polarizing plate 13 through the housing 1a and the protrusions 14. This structure makes it possible to suppress condensation on the polarizing plate 13, which is the front optical component, and therefore makes it possible to realize a highly reliable camera device 101 that can accurately recognize the outside world even when there are major changes in the environment, such as temperature and humidity.

Next, a second embodiment of the present invention will be described with reference to FIG. 5. Note that a duplicate description of the points common to the first embodiment will be omitted.

Figure 5 is a cross-sectional view of the camera device 102 according to this embodiment, with the convex portion 14 of the present invention hatched. This embodiment is characterized in that a structure (buffer material 16a or processed surface 16b) for improving heat transfer efficiency is provided between the convex portion 14 and the polarizing plate 13. As explained in Example 1, if the convex portion 14 is molded by aluminum die casting, there is a risk that the contact between the convex portion 14 and the polarizing plate 13 will be point contact, which may deteriorate the heat transfer efficiency at the contact point between the two.

In this embodiment, the protrusions 14 and the polarizing plate 13 are thermally connected through a buffer material 16a, such as an adhesive or a thermally conductive heat dissipation gel, as shown in the left diagram of FIG. 5. In this way, by connecting through a buffer material 16a that has a lower rigidity than the polarizing plate 13, the connection area can be secured regardless of the mounting state, and the heat of the protrusions 14 can be efficiently transferred to the polarizing plate 13. Furthermore, by thermally connecting the protrusions 14 and the polarizing plate 13 through a buffer material 16a, such as an adhesive that has a lower rigidity than the polarizing plate 13 or a member with high thermal conductivity, no extra force is applied from the protrusions 14 to the polarizing plate 13, and deformation of the polarizing plate 13, which is an optical component, can be prevented, so that the optical characteristics are improved compared to the configuration of Example 1.

As shown in the right diagram of FIG. 5, by providing a textured or sawtooth-shaped processed surface 16b at the tip of the protrusion 14, the protrusion 14 can be brought into contact with the polarizing plate 13 so as to bite into it, and by reliably connecting the protrusion 14 and the polarizing plate 13, the heat of the protrusion 14 can be efficiently transferred to the polarizing plate 13. Furthermore, the processed surface 16b at the tip of the protrusion 14 can fix the bite position in the polarizing plate 13, so the polarizing plate can also be held in position. Here, the processed surface 16b at the tip of the protrusion 14 is textured or sawtooth-shaped, but instead of textured or sawtooth-shaped, it may be needle-shaped or another shape that allows the protrusion 14 to bite into the polarizing plate 13.

In addition, if the convex portion 14 and the lens cover 12 are screwed together with the polarizing plate 13 sandwiched between them, the convex portion 14 and the polarizing plate 13 can be more securely connected, and the heat of the convex portion 14 can be more efficiently transferred to the polarizing plate 13.

Next, a third embodiment of the present invention will be described with reference to FIG. 6. Note that a duplicated description of the points common to the first embodiment will be omitted.

Figure 6 is a perspective view of the camera device 103 according to this embodiment. In the first embodiment, as shown in Figure 1, one convex portion 14 is provided at the bottom right and bottom left of each lens 4 (total of two). In contrast, the feature of this embodiment is that one convex portion 14 is provided at each of four locations, the top left, top right, bottom left, and bottom right, for each lens 4. In this way, by thermally connecting the housing 1c and the polarizing plate 13 with the four convex portions 14 centered on each lens 4, the heat of the housing 1c can be evenly transferred to the polarizing plate 13, and the temperature difference within the polarizing plate 13 can be made more uniform. This suppresses thermal deformation of the polarizing plate 13, and the optical characteristics of the camera device 103 are further improved.

In this embodiment, four convex portions 14 are provided for each lens 4, but substantially the same effect can be obtained even when three or five convex portions 14 are provided.

Next, a fourth embodiment of the present invention will be described with reference to FIG. 7. Note that a duplicated description of the points common to the first embodiment will be omitted.

Figure 7 is a cross-sectional view of the camera device 104 according to this embodiment, in which the protrusion 14 and the mounting portion 6a for fixing the camera module 6 are hatched. In the first embodiment, no particular mention was made of the structure for fixing the camera module 6 to the housing 1a. In contrast, the feature of this embodiment is that the mounting portion 6a for fixing the camera module 6 to the housing 1d is structured so as to be arranged in a straight line with the protrusion 14.

The heat from the image sensor circuit board 3, which is equipped with the image sensor 2, a heat-generating component, is transferred to the polarizing plate 13 through the camera holder 5, the mounting portion 6a, and the protruding portion 14. By arranging these three components in a straight line, as in this embodiment, the heat from the image sensor circuit board 3 can be efficiently transferred to the polarizing plate 13, and condensation on the optical components in front of the camera device 104 can be more efficiently suppressed.

Note that in FIG. 7, attention is focused on one protrusion 14, and the mounting portion 6a is illustrated as being arranged in a straight line with the protrusion 14, but if there are multiple protrusions 14, it is desirable to arrange the mounting portions 6a in a straight line also at positions corresponding to each of the protrusions 14. This can further increase the efficiency of heat transfer from the camera module 6 to the polarizing plate 13.

Next, a fifth embodiment of the present invention will be described with reference to FIG. 8. Note that a duplicated description of the points common to the third embodiment will be omitted.

Figure 8 is a perspective external view of the camera device 105 according to this embodiment. In the third embodiment, as shown in Figure 6, four rectangular prism-shaped protrusions 14 are arranged around the lens 4. In contrast, the feature of this embodiment is that four L-shaped protrusions 14a are arranged around the lens 4. This not only increases the rigidity of each of the protrusions 14a, but also increases the rigidity of the housing 1e as a whole in the vertical and horizontal directions.

Here, in a camera device 105 (stereo camera) equipped with a pair of left and right camera modules 6, the front side of the camera device 105 is captured, feature points common to both images are extracted from the pair of image information, and the number of pixels (parallax) at which the positions of the feature points are shifted between the pair of images is calculated by an integrated circuit, and the distance is calculated. Therefore, if there is a shift other than the original parallax between the pair of images, an error will occur in the distance measurement result. In addition, with the improvement in the performance of the camera device 105, such as a wider angle of view, high accuracy, and high speed response, the allowable amount of shift is reduced, and it is necessary to reduce the optical axis shift. Therefore, by improving the rigidity of the housing 1e in the vertical (y direction) and horizontal (z direction), it is possible to reduce the deformation of the housing 1e due to temperature distribution, etc., and to reduce the relative shift of the optical axes of the two camera modules 6. In other words, the camera device 105 has high measurement accuracy and high reliability against temperature changes.

Next, a sixth embodiment of the present invention will be described with reference to FIG. 9. Note that a duplicated description of the points common to the fifth embodiment will be omitted.

Figure 9 is an external view of the camera device 106 according to this embodiment. In the fifth embodiment, as shown in Figure 8, the lens cover 12 is closed on all four sides, making it difficult for outside air to penetrate inside the lens cover 12. In contrast, this embodiment is characterized in that slits 12a, 12b are provided on the top and bottom surfaces of the lens cover 12 to actively create airflow around the back surface of the polarizing plate 13 and the surface of the lens 4. Although only the top slit 12a is visible in Figure 9, a slit 12b is also provided on the bottom, allowing air to flow up and down.

The slits 12a and 12b in this embodiment are arranged to avoid the convex portion 14a, and the structure is such that the high-temperature convex portion 14a is not easily cooled by the air flow between the slits 12a and 12b. Condensation caused by the relationship between temperature, humidity, and saturated water vapor is unlikely to occur where there is air flow, so the air flow between the slits 12a and 12b and the heat transfer effect of the convex portion 14a can further suppress condensation on the polarizing plate 13. In addition, if the slits 12b are arranged below the polarizing plate 13, when condensation occurs on the polarizing plate 13, the water droplets that flow from the polarizing plate 13 to the lower surface can be discharged from the camera device 106, preventing rusting inside the camera device 106 and short circuits in the electrical circuits.

Although the prevention of condensation on the polarizing plate 13 has been described here, condensation on the surface of the lens 4 can also be prevented by the air flow between the slits 12a and 12b. Furthermore, the shape of the slits 12a and 12b is not limited to the shape shown in FIG. 9, and may be any number and shape of holes, for example, as long as they do not impede the air flow in the vertical direction.

Next, a seventh embodiment of the present invention will be described with reference to FIG. 10. Note that a duplicated description of the points common to the sixth embodiment will be omitted.

Figure 10 is an external view of the camera device 107 according to this embodiment. In the sixth embodiment, as shown in Figure 9, four L-shaped convex portions 14a are arranged around the lens 4. In contrast, the feature of this embodiment is that, instead of the convex portions 14a in Figure 9, an upper convex portion 14b connecting the upper pair of convex portions 14a shown in Figure 9 and a lower convex portion 14b connecting the lower pair of convex portions 14a of the lens 4 are used. In this way, in this embodiment, the convex portions 14b extending in the left-right direction (z direction) are used, so that the rigidity of the housing 1g in the left-right direction can be further improved. In addition, upper and lower second slits 15a and 15b corresponding to the upper and lower slits 12a and 12b of the lens cover 12 are provided in the center of the upper and lower convex portions 14b, and the structure does not obstruct the air flow between the slits 12a and 12b of the lens cover 12.

The camera device 107 of this embodiment has a long structure in the left-right direction, so the left-right direction is the direction in which it is most susceptible to deformation. Therefore, the connecting projection 14b is used to improve rigidity in the left-right direction, which reduces deformation of the housing 1g due to temperature distribution and the like, and reduces the misalignment of the optical axes of the pair of left and right camera modules 6. In other words, the camera device 107 has high measurement accuracy and high reliability in the face of temperature changes.

The present invention is not limited to the above-mentioned embodiments, but includes various modifications and combinations that do not deviate from the gist of the invention. Furthermore, the present invention is not limited to those that have all of the configurations described in the above-mentioned embodiments, but also includes those in which some of the configurations have been omitted.

100-107 Camera device 1 Housing 2 Imaging element 3 Imaging element circuit board 4 Lens 5 Camera holder 6 Camera module 6a Mounting portion 7-9 Circuit element 10 Camera circuit board 11 Housing cover 12 Lens cover 12a, 12b Slit 13 Polarizing plate 14, 14a, 14b Convex portion 15a, 15b Slit 16a Cushioning material 16b Processing surface 20 Front glass 21 Outside air

Claims (11)

a camera module having a lens and an image sensor;
a housing that holds the camera module such that the lens protrudes from a front surface of the housing;
a lens cover that covers the lens so as to arrange an optical component in an optical axis direction of the lens;
A camera device comprising:
the housing includes a protrusion protruding forward from a periphery of the lens, and a tip of the protrusion is thermally connected to the optical component ;
A plurality of the protrusions are arranged around the lens,
The housing and the protruding portion are integrally molded by aluminum die casting,
A camera device that is installed on the inner surface of a vehicle windshield . 2. The camera device according to claim 1 , wherein the optical component is a polarizing plate or a protective plate. 2. The camera device according to claim 1 , wherein the convex portion is isolated from the outside air by being covered by the lens cover. 2. The camera device according to claim 1 , wherein the protrusion has a portion other than a tip thereof that does not come into contact with the lens cover. 2. The camera device according to claim 1 , wherein a cushioning material having a lower rigidity than said optical component is disposed on the tip of said convex portion. 2. The camera device according to claim 1 , wherein the tip of the protrusion is provided with a matte or sawtooth processed surface. 2. The camera device according to claim 1 , wherein three or more of said convex portions are arranged around said lens with said lens as a center. 2. The camera device according to claim 1 , wherein the housing has a mounting portion for fixing the camera module disposed in a position that is in line with the protrusion. 2. The camera device according to claim 1 , wherein the convex portion has any one of a rectangular prism shape, a cylindrical shape, a plate shape, and a cylindrical shape with an L-shaped cross section. 2. The camera device according to claim 1 , wherein the lens cover has slits on the top and bottom surfaces. 2. The camera device according to claim 1 , wherein the camera device is a stereo camera having a pair of left and right camera modules built-in.

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