camera unit

Abstract

A camera unit is provided in which magnification of the size of a polarizing filter and a product due to a widening of the viewing angle is suppressed. To minimize magnification of a product size due to a widening of the viewing angle, a configuration is provided in which a lens, an imaging element that receives light through the lens, and a lens filter arranged on the opposite side of the imaging element with respect to the lens and perpendicular to an optical axis of the lens, and the lens filter is arranged such that the center of the lens filter is displaced from a central axis of the lens in the direction of the widening of the viewing angle.

Description

Technical area

[0001] The present invention relates to an in-vehicle camera unit used in an advanced driving assistance system or the like. State of the art

[0002] Advanced driver assistance systems, such as collision mitigation braking, are effective means of preventing traffic accidents. These systems use an in-vehicle camera, millimeter-wave radar, or the like as an external detection sensor.

[0003] When an in-vehicle camera is mounted on a four-wheeled vehicle as an external detection sensor, a housing of the in-vehicle camera is generally attached to an upper portion of the vehicle interior. In this case, the in-vehicle camera images a scene or object in front of the vehicle through the windshield. At this time, reflection from the windshield causes the vehicle interior, such as the dashboard, to be projected onto the camera's imaging surface, and the object detection performance may deteriorate. PTL 1 and PTL 2 are known as conventional techniques to address this problem.

[0004] For example, in the abstract of PTL 1, "an image recognition device using an in-vehicle stereo camera prevents projection onto an upper portion of an instrument panel due to reflection on an inner side of a windshield to avoid influence on recognition performance" is disclosed as a problem. As a solution, it is disclosed that "a polarizing filter 31 is attached to a front surface of a camera 2a (2b) so that a polarization axis thereof becomes vertical. However, a direction of a glass surface on the front surface of the camera is not necessarily vertical due to a curvature of the windshield 10 in a right-left direction, and thus the polarizing filter 31 of the camera is attached to have an offset angle θ (θ = tan -1(sinα × sinβ / cosα), where α is a vertical component and β is a horizontal component of an angle formed between an optical axis of the camera and the windshield on the optical axis) with respect to the vertical direction.” As described above, the in-vehicle camera in PTL 1 has a structure in which the polarizing filter is arranged in front of a lens.

[0005] Additionally, in the problem column of the abstract of PTL 2, "in a vehicle-mounted camera... projection of a dashboard or the like onto a windshield is prevented." Paragraph 0015 of the specification discloses, "the camera 10 includes a camera body 20 and a housing 22 that houses the camera body 20." Paragraph 0023 discloses, "an opening 22a is formed in the housing 22 on a side facing an arrangement position of a harness coupler housing portion 42." Paragraph 0025 discloses, "the opening of the opening 22a and the position of the lens unit 20c are appropriately determined according to a field of view (required viewing angle) to prevent unnecessary light from entering." Fig. 3 and Fig. 4 of the same document, the housing 22 covers a portion other than the front of the lens unit 20c to prevent unnecessary light from entering. As described above, in the vehicle-mounted camera of PTL 2, by providing a housing having a shape that prevents projection of a dashboard or the like onto the windshield, unnecessary light is prevented from entering the lens unit. Citation listPatent literature PTL 1: JP 2001-94842 A PTL 2: JP 1999-78737 A Summary of the inventionTechnical problem

[0006] In recent years, advanced driver assistance systems have been required to further enhance functions such as handling collision damage reduction braking when turning right or left at an intersection. Accordingly, in-vehicle cameras have been required in recent years to expand a horizontal angle of view. In addition, in an in-vehicle camera for a vehicle (a large truck, a large bus, or the like) with a high camera mounting position and a short length from the camera mounting position to the front end of the vehicle, a wide vertical angle of view is also required so that the bottom of the camera can be monitored. Furthermore, as the mounting rate of in-vehicle cameras on small vehicles, such as light vehicles, is also increasing, in-vehicle cameras have been required in recent years to expand a viewing angle while reducing the size.

[0007] Generally, when the in-vehicle camera has an expanded field of view, unnecessary light projected onto an imaging element also increases. Even in the in-vehicle camera in which the camera's imaging range is expanded in a specific direction (any of up, down, left, and right) with respect to the lens optical axis, considering the handling of the collision damage reduction brake when turning right or left at an intersection and mounting on a large truck or a large bus, the projection of unnecessary light can be suppressed by using the polarizing filter in PTL 1 and the housing (lens hood) in PTL 2.However, if the technical ideas of both PTLs are applied as they are, the polarizing filter and the housing (lens hood) are enlarged according to the widening of the angle of view, which leads to an increase in the product size of the entire camera, and a possibility is considered that the visibility from the vehicle interior is deteriorated depending on the vehicle for mounting or the visibility law is violated at the time of mounting the in-vehicle camera.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide a camera unit in which an increase in a size of a polarizing filter and a product due to a broadening of a view angle is suppressed. Solution to the problem

[0009] In order to solve the above problems, according to the present invention, a lens, an imaging element that receives light through the lens, and a lens filter arranged on an opposite side of the imaging element with respect to the lens and perpendicular to an optical axis of the lens are provided, wherein the lens filter is arranged such that a center of the lens filter is shifted from a central axis of the lens in a direction of broadening a viewing angle. Advantageous effects of the invention

[0010] With the camera unit of the present invention, it is possible to suppress an increase in the size of a lens hood and a product due to a widening of the viewing angle. Problems, configurations, and effects different from those described above will be clarified by the following description of examples. Short description of the drawings Fig. 1 is a plan view of a vehicle on which a camera unit in Example 1 is mounted. Fig. 2 is a perspective view showing a schematic configuration of the camera unit in Example 1. Fig. 3 is a cross-sectional view of a periphery of a left camera in the camera unit of Fig. 2. Fig. 4 is a perspective view showing a schematic configuration of a camera unit in Example 2. Fig. 5 is a cross-sectional view of a periphery of a left camera in the camera unit of Fig. 4. Fig. 6 is a cross-sectional view of a periphery of a left camera in a camera unit in Example 3. Fig. 7A is a perspective view showing a schematic configuration of a camera unit in Example 4. Fig. 7B is a perspective view showing the schematic configuration of the camera unit in Example 4. Fig. 8A is a perspective view showing a schematic configuration of a camera unit in Example 5. Fig. 8B is a perspective view showing the schematic configuration of the camera unit in Example 5. Description of embodiments

[0011] Hereinafter, examples of a camera unit in the present invention will be described with reference to the drawings. Example 1

[0012] First, a camera unit 1 according to Example 1 of the present invention will be described with reference to Fig. 1 to Fig. 3 described. <Installationsform der Kameraeinheit 1 an dem Fahrzeug V>

[0013] Fig. 1 is a plan view of a vehicle V on which a camera unit 1 is mounted, viewed from above in the present example. The camera unit 1 is a stereo camera installed in a vehicle interior of the vehicle V so as to face forward. As shown in the drawing, cameras are configured such that the imaging area (solid fan shape) of a left camera is inclined to the right with respect to an optical axis direction of the lens (solid arrow), and the imaging area (broken fan shape) of a right camera is inclined to the left with respect to the optical axis direction of the lens (broken arrow), that is, the imaging directions of both cameras are not parallel.

[0014] Therefore, a stereo imaging area imaged by the left and right cameras is formed in front of the camera unit 1, an imaging area imaged only by the left camera is formed on the right side of the stereo imaging area, and an imaging area imaged only by the right camera is formed on the left side of the stereo imaging area. By designing the imaging areas of the left and right cameras in this way, the angle of view in the imaging area of ​​the camera unit 1 is expanded in the horizontal direction. <Konfiguration der Kameraeinheit 1>

[0015] Fig. 2 is a perspective view showing a schematic configuration of the camera unit 1 in Example 1. As shown herein, the camera unit 1 includes a housing 11, a pair of right and left lenses 12, a pair of right and left lens filters 13, and a pair of right and left lens hoods 14. Note that in the following description, it is assumed that the respective directions of top, bottom, front, back, left, and right are defined as shown in the drawing.

[0016] The casing 11 is a metal casing that covers an imaging element 15, an image processing circuit, and the like (not shown) necessary for generating image data, and is made, for example, by aluminum die-casting or the like with high mechanical strength and excellent heat dissipation.

[0017] The lens 12 is an optical system for condensing light, which is arranged in front of the imaging element 15. The lens 12 is installed so that it protrudes from the front surface of the housing 11. Note that the lens 12 is not necessarily a single lens and may have a configuration in which a plurality of lenses are combined to obtain desired optical properties.

[0018] The lens filter 13 is a light-transmitting element arranged in front of the lens 12 and is, for example, a polarizing filter. Note that if only the function of protecting the lens 12 is required, the lens filter 13 may comprise a glass plate or a plastic plate without a polarizing function.

[0019] The lens hood 14 has a long side opening closed by the lens filter 13 on a front surface. The lens hood 14 is a light-shielding portion for preventing unnecessary light from outside the imaging areas of the left and right cameras (e.g., the dashboard direction) from entering the lens 12 and deteriorating the quality of image data, and is configured to cover the lens 12. Note that in the present example, the lens hood 14 also has a function of fixing and holding the lens filter 13.

[0020] Fig. 3 is a cross-sectional view of the periphery of the left camera in the camera unit 1 of Fig. 2. It should be noted that if Fig. 2 is horizontally inverted, the inverted figure is equivalent to the cross-sectional view of the circumference of the right camera, and thus the detailed description of the right camera structure is omitted below.

[0021] As mentioned with reference to Fig. 1, in the camera unit 1 in the present example, the imaging range of the left camera is tilted to the right side and the imaging range of the right camera is tilted to the left side, so that the entire camera unit 1 has a wide angle of view in the horizontal direction.

[0022] Therefore, as in Fig. 3, in the right front of the lens 12 of the left camera, it is necessary to expand the lens filter 13 in the right direction to cover the entire wide field of view to the right, and it is necessary to arrange the lens hood 14 far away so as not to block the wide field of view to the right. On the other hand, in the left front of the lens 12 of the left camera, the lens filter 13 may be narrowed as long as the lens filter 13 covers the entire narrow field of view to the left, and the lens hood 14 may be arranged so as to be as close as the lens hood 14 does not block the narrow field of view to the left.

[0023] Thus, in the present example, the horizontal center axes of the lens filter 13 and the lens hood 14 are arranged to be closer than the horizontal center axis of the lens 12 in the rightward direction (i.e., a direction in which the imaging field is wide) by a predetermined offset amount δ. As a result, it is possible to maintain the original functions of the lens filter 13 and the lens hood 14 while reducing the size of the left side of the lens filter 13 and the lens hood 14 compared to the arrangement in which the horizontal center axes coincide with each other. Thus, it is possible to reduce the size of the entire camera unit 1 while expanding the angle of view of the camera unit 1 in the horizontal direction.

[0024] Note that the magnitude of the offset δ in the left camera is approximately proportional to the size of the right field of view of the left camera and inversely proportional to the size of the left field of view. Similarly, the magnitude of the offset δ in the right camera is approximately proportional to the size of the left field of view of the right camera and inversely proportional to the size of the right field of view.

[0025] According to the camera unit described above in the present invention, it is possible to suppress an increase in a size of a lens hood and a product due to a widening of a view angle. Example 2

[0026] Next, a camera unit 1 according to Example 2 of the present invention will be described with reference to Fig. 4 and Fig. 5. Note that the repetitive description of points common to Example 1 is omitted.

[0027] In Example 1, in order to expand the angle of view of the camera unit 1 in the horizontal direction, the imaging areas of the left and right cameras are made different on the left and right sides (horizontal direction) with respect to the optical axis of the lens. In this case, as shown in Fig. 3, since the size of the lens filter 13 and the size of the opening of the lens hood 14 are not optimized for the size of the lens 12, a possibility that a diffuse reflection of a part of the light (for example, light passing through the right side of the lens filter 13 in Fig. 3) that has passed through the lens filter 13 has occurred on the front surface of the housing 11, the side surface of the lens 12, the rear surface of the lens filter 13, the inner surface of the lens hood 14, and the like, and then the light from the front surface of the lens 12 is incident. In such a case, since the quality of the image data is deteriorated by the diffusely reflected light, it is necessary to suppress the diffuse reflection in the lens hood 14.

[0028] Thus, in the present example, as in the perspective view of Fig. 4 and the cross-sectional view of Fig. 5, by providing the light shielding member 16 for reducing the diffuse reflection of ambient light on the inside of the lens hood 14, the diffuse reflection in the lens hood 14 is suppressed.

[0029] The light-shielding member 16 in the present example is formed by a member capable of shielding light in the visible range and having optically opaque black. Furthermore, the light-shielding member 16 is cut into a conical shape according to the imaging range of the lens 12, and the cut surface is subjected to a surface treatment such as embossing so that light is not reflected on the cut surface. As a result, even if the lens filter 13 and the opening of the lens hood 14 do not match the size of the lens 12 (see Fig. 5), it is possible to suppress the diffuse reflection in the lens hood 14 and to suppress deterioration of the quality of image data due to the diffuse reflection (projection of a dashboard onto the imaging element 15 or the like).

[0030] Here, the light shielding member 16 is described with reference to the cross-sectional view of Fig. 5 in more detail. As shown here, the light-shielding member 16 also has a function of securing the lens filter 13 by pressing the lens filter 13 against the lens hood 14 from the inside. As a result, it is not necessary to provide a member (in Fig. 3 not shown) only for attaching the lens filter 13, and thus it is possible to reduce the number of components constituting the camera unit 1.

[0031] Furthermore, as in Fig. 5, the light-shielding member 16 is formed to surround the outer periphery of the lens 12, and its front surface is formed obliquely with respect to the lens filter 13. That is, the light-shielding member 16 has a shape in which the side of the lens 12 is thin and the opposite base side is thick, ensuring the necessary mechanical strength while not shielding the imaging area of ​​the left camera.

[0032] It should be noted that in Fig. 5, when the lens filter 13 is moved in the rightward direction, the width is narrow and the front inclination on the left side (first light-shielding area) of the light-shielding member 16 is steep, whereas the width is wide and the front inclination on the right side (second light-shielding area) of the light-shielding member 16 is gentle. Example 3

[0033] Next, a camera unit 1 according to Example 3 of the present invention will be described with reference to Fig. 6. Note that the repetitive description of points common to the examples described above is omitted.

[0034] In Example 2, the diffuse reflection within the lens hood 14 is suppressed by disposing the light-shielding member 16 within the lens hood 14. However, in the present example, instead of the light-shielding member 16 of Example 2, as shown in the cross-sectional view of Fig. 6, a light-shielding body 17 comprising optically opaque black is provided at a portion exposed inside the lens hood 14 on the front surface of the housing 11. Note that the light-shielding body 17 may be painted or may be bonded to another member.

[0035] Even if the housing 11 has metallic luster, such a black light-shielding body 17 suppresses the diffuse reflection within the lens hood 14. Thus, even if unnecessary light is incident on the inside of the lens hood 14, it is possible to suppress the reflection on the front surface of the housing 11 and reduce the projection of the unnecessary light onto the imaging element 15. Example 4

[0036] Next, a camera unit 1 according to Example 4 of the present invention will be described with reference to Fig. 7A and Fig. 7B. Note that the repetitive description of points common to the examples described above is omitted.

[0037] In Examples 1 to 3, the camera unit 1 in which the horizontal angle of view is expanded to handle the collision damage reduction brake when turning right or left at the intersection was described as an example. However, in a camera unit 1 for a vehicle having a high camera mounting position and a short length from the camera mounting position to the front end of the vehicle, such as a camera unit for a large truck or a large bus, the vertical angle of view must be expanded so that the bottom of the camera can be monitored.

[0038] Therefore, in the camera unit 1 in the present example, as shown in Fig. 7A, the lens filter 13 and the lens hood 14 are formed in a vertically elongated shape, and the vertical center axes of the lens filter 13 and the lens hood 14 are arranged to be biased downward (i.e., in a direction in which the imaging range is wide) from the vertical center axis of the lens 12 by a predetermined offset amount δ. As a result, it is possible to monitor the bottom of the camera unit 1 when it is mounted on a large truck or a large bus, and it is also possible to reduce the size of the camera unit 1.

[0039] It should be noted that even if the configuration of the present example is adopted, the light shielding member 16 in the lens hood 14 (see Fig. 7B) or the light shielding body 17 may be provided on the front surface of the housing 11 to suppress the diffuse reflection in the lens hood 14. Example 5

[0040] Next, a camera unit 1 according to Example 5 of the present invention will be described with reference to Fig. 8A and Fig. 8B. Note that the repetitive description of points common to the examples described above is omitted.

[0041] In Example 4, the field of view of the camera unit 1 is extended downward, assuming that the camera unit 1 is mounted on a large truck or a large bus. On the other hand, in the case of a camera unit mounted on a vehicle with a low vehicle height, a cleaning robot, or the like, a wide viewing angle with an upwardly extended field of view is required so that the top of the camera unit 1 can also be monitored.

[0042] Therefore, in the camera unit 1 in the present example, as shown in Fig. 8A, the lens filter 13 and the lens hood 14 are formed in a vertically elongated shape, and the vertical center axes of the lens filter 13 and the lens hood 14 are arranged to be biased upward (that is, in a direction in which the imaging range is wide) from the vertical center axis of the lens 12 by a predetermined offset amount δ. As a result, it is possible to monitor the top of the camera unit 1 when the camera unit 1 is mounted on a vehicle with a low vehicle height, a cleaning robot, or the like, and to reduce the size of the camera unit 1.

[0043] It should be noted that even if the configuration of the present example is adopted, the light shielding member 16 in the lens hood 14 (see Fig.8B) or the light shielding body 17 may be provided on the front surface of the housing 11 to suppress the diffuse reflection in the lens hood 14. List of reference symbols 1 camera unit 11 housings 12 lenses 13 lens filters 14 Lens hood 15 Illustration element 16 Light shielding element 17 Light shielding bodies QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2001-94842 A

[0005] JP 1999-78737 A

[0005]

Claims

[1] Camera unit, comprising: a lens; an imaging element that receives light through the lens; and a lens filter arranged on an opposite side of the imaging element with respect to the lens and perpendicular to an optical axis of the lens, wherein the lens filter is arranged such that a center of the lens filter is shifted from a center axis of the lens. [2] The camera unit according to claim 1, further comprising a light-shielding element that shields light incident on the lens, wherein the light shielding member is formed such that a front surface thereof is arranged to be oblique with respect to the lens filter. [3] The camera unit according to claim 1, further comprising a light-shielding element that shields light incident on the lens, wherein the light shielding member has a first light shielding area and a second light shielding area wherein the first light-shielding region and the second light-shielding region are arranged with a non-light-shielding region through which light passes to the lens, and which is arranged therebetween, and wherein the first light-shielding region and the second light-shielding region have different front inclinations. [4] The camera unit of claim 1, further comprising a light-shielding element that shields light incident on the lens, wherein a front surface of the light shielding member is arranged along a viewing angle of the lens. [5] The camera unit according to claim 2, wherein the light shielding member is disposed between the lens and the lens filter. [6] Camera unit according to claim 2, further comprising a fastener that secures the lens filter, wherein the light shielding element also serves as the fastening element. [7] Camera unit according to claim 1, wherein the camera unit is a stereo camera comprising a plurality of lenses and a plurality of imaging elements, and The imaging directions of the plurality of lenses are not parallel. [8] The camera unit of claim 1, further comprising a lens hood comprising an opening closed by the lens filter, wherein the lens hood is arranged such that a center of the lens hood is shifted from a center axis of the lens. [9] The camera unit according to claim 1, wherein the lens filter is long in a horizontal direction and a horizontal center of the lens filter is offset from a horizontal center axis of the lens in the horizontal direction. [10] The camera unit according to claim 1, wherein the lens filter is long in a vertical direction and a vertical center of the lens filter is offset from a vertical center axis of the lens in the vertical direction.

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