Imaging apparatus

Abstract

To provide an imaging apparatus that can reduce the effect of a windshield on an imaging result.SOLUTION: An imaging apparatus that is placed on the inside of a windshield of a moving object and that photographs the outside of the moving object through the windshield has a lens unit for forming an optical image of a subject on a light-receiving surface of an image pickup device, and is characterized in that a distance from an optical axis to an edge closest to the windshield in a first optical system on the side closest to the subject of the lens unit is shorter than the maximum diameter of the first optical system.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an imaging device disposed on a moving object. [Background technology]

[0002] A distance measuring camera system that uses the principle of triangulation to measure the distance to an object is installed in a vehicle and is used to measure the distance to an obstacle around the vehicle. Examples of distance measuring camera systems include a stereo camera system and an imaging plane phase difference distance measuring camera system.

[0003] A stereo camera system has two cameras positioned parallel to each other at a specified distance, detects the shift caused by parallax of the subject in the images captured by each camera, and uses this to estimate the distance to the subject.

[0004] An image plane phase difference ranging camera system takes images using a single camera equipped with an image sensor called an image plane phase difference sensor. Light that passes through an imaging optical system is incident on multiple pixels formed on the image sensor, and the system detects the shift in the image signals generated, and uses this as a basis to estimate the distance to the subject.

[0005] These distance measuring camera systems are mounted on the inside of the windshield of a vehicle and used as imaging devices to capture images of the outside of the vehicle. The imaging devices have a lens unit including a wide-angle lens with a wide angle of view, enabling image recognition of a wide area around the vehicle.

[0006] In order to ensure the brightness and resolution of a wide-angle lens, it is unavoidable to increase the size of the lens. However, for example, in Patent Document 1, the size of the lens unit can be reduced by making the bottom of the wide-angle lens smaller, thereby achieving a reduction in the size of the entire imaging device. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2022-009118 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the above-mentioned conventional example, when the imaging device is mounted on the inside of the windshield of the vehicle, it is affected by the windshield.

[0009] The windshield is curved and attached at an angle, and the degree of curvature and the angle of inclination vary depending on the position, and there is also variation in thickness. Therefore, the larger the area of ​​the windshield within the angle of view, the more distortion is affected during shooting, which leads to distortion of the captured image. In addition, if the projection area is large, there is an increased possibility that dirt on the windshield will enter the angle of view, which will interfere with shooting.

[0010] Therefore, an object of the present invention is to provide an imaging device capable of reducing the influence of the windshield on the imaging results. [Means for solving the problem]

[0011] In order to solve the problem, the present invention provides a method for producing a liquid crystal display comprising: An imaging device that is disposed inside a windshield of a moving body and captures an image of the outside of the moving body through the windshield, a lens unit for forming an optical image of a subject on a light receiving surface of an image sensor; The lens unit is characterized in that in a first optical system closest to the subject, the distance from the optical axis to the end closest to the windshield is shorter than the maximum diameter of the first optical system. Effect of the Invention

[0012] According to the present invention, it is possible to provide an imaging device capable of reducing the influence of the windshield on the imaging result. [Brief description of the drawings]

[0013] [Figure 1] 1A to 1C are diagrams illustrating an example of an arrangement of an imaging device according to an embodiment of the present invention when the imaging device is arranged on a vehicle. [Diagram 2] 1 is a diagram showing a specific example in which an imaging device according to an embodiment is disposed near an upper portion of a windshield of a vehicle. [Diagram 3] 1 is a functional block diagram showing an example of the configuration of an imaging device according to an embodiment of the present invention. [Figure 4] FIG. 1A is an external perspective view of an imaging device 1 according to an embodiment of the present invention, and FIG. 1B is an exploded perspective view of the imaging device according to the embodiment of the present invention. [Diagram 5] 1 is a cross-sectional view of an imaging device 1 according to an embodiment of the present invention, taken along an X-axis direction including an optical axis. [Figure 6] 2 is a cross-sectional view of the image sensor unit 5 according to the embodiment of the present invention, taken along the X-axis direction including the optical axis. [Figure 7] 13A to 13F are external views and perspective views, respectively, as viewed from the optical axis direction, for explaining examples of various shapes of wide-angle lens 84. FIG. [Figure 8] FIG. 1A is a diagram showing an example of placing an imaging device according to an embodiment of the present invention near the upper part of a vehicle's windshield (front windshield 103), and FIG. 1B is a diagram showing an example of placing a general imaging device equipped with a circular wide-angle lens. [Figure 9] 9A and 9B are diagrams showing examples of the angles of view and the contact points with the windshield when viewed from the optical axis direction. [Figure 10] 1A to 1C are diagrams for explaining the relationship between an image size 91 and an image circle 92 of an imaging device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiment. In each drawing, the same members or elements are given the same reference numbers, and duplicated descriptions are omitted or simplified. Note that the drawings used in the following description are simplified schematic drawings, and the dimensional ratios and the like in the drawings do not match the actual ones.

[0015] 1(A) to 1(C) are diagrams showing examples of the arrangement of an imaging device 1 according to an embodiment of the present invention when it is arranged on a vehicle. The imaging device 1 of the present invention is an on-board camera arranged on a vehicle 100, which is a moving body. Note that the moving body is not limited to vehicles such as automobiles, and may be any type of device that is capable of moving, such as a motorcycle, bicycle, ship, or airplane.

[0016] 1(A) is a diagram showing an example in which an imaging device 1 is disposed near the upper part of a windshield (front windshield). The imaging device 1 is disposed inside the windshield of a moving object, and by capturing an image of the outside of the moving object through the windshield, it is possible to monitor the area ahead when the vehicle 100 is traveling. Here, the windshield refers to a window in front of a moving object such as a vehicle, through which the view ahead can be seen.

[0017] The imaging device 1 can be installed in various locations on the vehicle 100. For example, Fig. 1(B) is a diagram showing an example in which the imaging device 1b is installed on the top of the dashboard, and Fig. 1(C) is a diagram showing an example in which the imaging device 1c is installed near the top of the rear window (rear windshield) at the rear. The imaging device 1c is installed at the rear of the vehicle 100 for monitoring the rear of the vehicle 100. Note that the vehicle-mounted camera 1 is not limited to these locations, and may be installed in a position where it can capture images of the sides of the vehicle.

[0018] 2 is a diagram showing a specific example of the case where the imaging device 1 according to the embodiment is disposed near the upper part of the front windshield or rear windshield of a vehicle. The imaging device 1 is attached to a windshield 103 of a vehicle 100 via a bracket 101 and a bracket 102.

[0019] Bracket 101 and bracket 102 are attached by adhesive to the upper side of the vehicle interior of glass 103 of the vehicle, and fix imaging device 1. Bracket 101 and bracket 102 are fixed to imaging device 1 by press fitting or using fastening parts (not shown) such as screws.

[0020] A brief description will be given of the functions of the imaging device 1. Fig. 3 is a functional block diagram showing an example of the configuration of the imaging device 1 according to an embodiment of the present invention. Some of the functional blocks shown in Fig. 3 are realized by causing a camera control IC 11 of the imaging device 1 or a CPU (not shown) included in the path generation ECU 104 to execute a computer program stored in a memory (not shown).

[0021] However, some or all of these may be realized by hardware. For the hardware, a dedicated circuit (ASIC) or a processor (reconfigurable processor, DSP) may be used. Furthermore, the functional blocks shown in Fig. 3 do not have to be built into the same housing, and may be configured by separate devices connected to each other via signal paths.

[0022] Light from the object to be imaged is incident on the lens unit 8. The light from the object to be imaged reaches the image sensor 9 via the lens unit 8 and is received by the image sensor 9. That is, the lens unit 8 forms an optical image of the subject on the light receiving surface of the image sensor. The image sensor 9 outputs a signal according to the received light.

[0023] The imaging element 9 is a semiconductor image sensor element such as a complementary metal oxide semiconductor (CMOS), etc. Using the imaging element 9, it is possible to obtain the distance to an object (subject) by an imaging surface phase difference method, as described later.

[0024] In the imaging surface phase difference method, light passes through the lens unit 8 and enters a plurality of pixels formed on the imaging sensor, and the shift in the generated image signals is detected, and the distance to the subject is calculated by the camera control IC 11, which will be described later. That is, the control IC 11 has a function capable of calculating the distance to the subject based on the phase difference of signals from a plurality of pixels of the imaging element 9 of this embodiment.

[0025] A signal output circuit is provided on the imaging element substrate 10. The signal output circuit outputs an image signal indicating an image of an object to be imaged, based on a signal output from the imaging element 9 in response to light incident on the lens unit 8. The image signal output from the imaging element substrate 10 is input to the main substrate 6.

[0026] The main body board 6 is connected to the camera control IC 11, which processes the image signal output from the imaging element board 10. The image signal processed by the camera control IC 11 can be output to a device (e.g., a route generation ECU 104) in the vehicle 100 via the main body board 6. The camera control IC 11 has a built-in CPU (not shown) as a computer, and controls the entire imaging device 1 by executing a computer program stored in a memory (not shown).

[0027] The route generation ECU 104 in the vehicle 100 also includes a CPU as a computer, and generates a travel trajectory of the vehicle 100 and route information related to the travel trajectory based on measurement signals, external information, object distance information, distance information, and the like output from the measuring instruments, etc. 107. Note that the measuring instruments, etc. 107 may acquire various information from, for example, an external server, etc.

[0028] The vehicle control device 105 controls the driving unit 106 so that the vehicle 100 passes through the route determined by the route information, based on the route information and vehicle information acquired from measuring instruments 107. Data processed by the CPU in the route generation ECU 104 and computer programs executed are stored in a memory (not shown).

[0029] The drive unit 106 is a drive member for driving the vehicle, and includes, for example, a power unit such as an engine or a motor that generates energy for rotating the tires, and a steering unit that controls the traveling direction of the vehicle.

[0030] The driving section 106 also includes a gear box for rotating the tires using the energy generated by the power section, a gear control unit for controlling the configuration inside the gear box, a brake unit for performing braking operation, and the like.

[0031] The vehicle control device 105 controls the driving unit 106 to adjust the driving amount, braking amount, steering amount, etc. of the vehicle 100 so that the vehicle passes through a route corresponding to the route information. Specifically, the vehicle control device 105 controls the brakes, steering, gear configuration, etc. to operate the vehicle 100.

[0032] Fig. 4(A) is an external perspective view of the imaging device 1 according to the embodiment of the present invention, and Fig. 4(B) shows an exploded perspective view of the imaging device 1 according to the embodiment of the present invention. Fig. 5 shows a cross-sectional view of the imaging device 1 according to the embodiment of the present invention in the X-axis direction including the optical axis, and Fig. 6 shows a cross-sectional view of the imaging element unit 5 according to the embodiment of the present invention in the X-axis direction including the optical axis.

[0033] The X-axis, Y-axis, and Z-axis are defined as shown in Fig. 4(A). When the imaging device 1 is placed near the windshield of the vehicle as shown in Fig. 1(a), the X+ axis direction is the direction toward the front of the vehicle (the direction in which the windshield exists relative to the imaging device 1), and the X- axis direction is the direction toward the rear of the vehicle (the direction in which the rear windshield exists relative to the imaging device 1).

[0034] The direction of the X-axis also coincides with the direction of the optical axis of the imaging unit 5, which will be described later. Similarly, the Y+ axis direction indicates the right side relative to the forward movement of the vehicle, and the Y- axis direction indicates the left side relative to the forward movement of the vehicle. Similarly, the Z+ axis indicates the upper side (upward) of the imaging device 1, and the Z- axis indicates the lower side (downward) of the imaging device 1. The direction of the Z-axis also coincides with the direction perpendicular to the direction of the optical axis of the imaging unit 5, which will be described later.

[0035] As shown in FIG. 4(B), the imaging device 1 of this embodiment mainly includes an upper housing 2, a lower housing 3, and a rear housing 4, and contains an imaging element unit 5, a main body board 6, etc.

[0036] The upper housing 2 is made of a metal such as aluminum or resin, and forms a front outer shell of the imaging device 1. The upper housing 2 includes a front wall portion 21, an upper wall portion 22, a right side wall portion 23, a left side wall portion 24, a front wall portion 25, and an upper wall portion 26.

[0037] The front wall portion 21 has a flat plate shape parallel to an imaging element, which will be described later. The front wall portion 21 is provided with a hole 21a into which the imaging element unit 5 is inserted. The upper wall portion 22 intersects with the front wall portion 21.

[0038] The upper wall 22 extends slightly forward and downward from the front end surface of the front wall 21, and has a flat plate shape. Heat dissipation fins (not shown) may be arranged on the upper side of the upper wall 22. A main body board 6 on which electronic components described below are mounted is arranged on the lower side of the upper wall 22. The front wall 21 of the upper housing 2 is arranged so as to face the outside of the vehicle, and the upper housing 2 serves as an attachment part to the vehicle.

[0039] The lower housing 3 is made of a metal such as aluminum or resin, and forms a lower outer shell of the imaging device 1. A flat portion 31 of the lower housing 3 has a flat plate shape parallel to the upper wall portion 22. The lower housing 3 is installed so as to close the lower side of the upper housing 2.

[0040] The rear housing 4 is made of a metal such as aluminum or resin, and forms the rear shell of the imaging device 1. A front wall 41 of the rear housing 4 is disposed parallel to the imaging element board 10, and is joined to the upper housing 2 by fastening parts such as screws 7. A rear wall 42 of the rear housing 4 may be provided with fins (not shown) for dissipating heat.

[0041] The imaging element unit 5 is mainly composed of a lens unit 8, an imaging element 9, and an imaging element substrate 10. Specific configuration examples of the imaging element unit 5 and the lens unit 8 are shown in Fig. 5 and Fig. 6. As shown in Fig. 6, the lens unit 8 has a cylindrical lens barrel 81 made of metal such as aluminum or resin. Inside the lens barrel 81, multiple lenses 82 and multiple spacers 83 are housed.

[0042] Furthermore, a wide-angle lens 84 is housed at the end of lens unit 8 on the imaging subject side as the first optical system closest to the subject, and wide-angle lens 84 is held by a press ring 85. Lens 82 and wide-angle lens 84 are made of a light-transmitting material such as glass or resin. Spacer 83 and press ring 85 are made of a metal such as aluminum or resin. The first optical system closest to the subject of the lens unit does not have to be a lens, and may be a protective transparent plate.

[0043] 6 shows an example in which the multiple lenses 82 and spacers 83 are alternately housed in the same number and shape, but this is just one example, and they may be different in shape and number, and the order in which they are housed does not matter. The wide-angle lens 84 has an outer shape when viewed from the optical axis direction (X-axis direction) in which the multiple lenses 82 are aligned, and the end in the Z+ direction is not a perfect circle, but has a shape in which the end is cut in a straight line in the Y-axis direction. The detailed shape will be described later.

[0044] 6, an end of the lens unit 8 is attached at a substantially right angle to the imaging element substrate 10 via an adhesive or the like (not shown). However, the lens unit 8 does not have to be attached directly to the imaging element substrate 10. For example, the lens unit 8 may be attached indirectly via the upper housing 2 or other members.

[0045] The imaging element 9 is attached to an imaging element board 10 on the lens unit 8 side, and is housed in a cylindrical portion of the lens unit 8. The imaging element 9 is the main heat source for the imaging element unit 5. The imaging element board 10 is in the form of a flat plate extending in the vertical and horizontal directions. A control circuit for controlling the imaging element 9 and the like are arranged on the imaging element board 10.

[0046] The imaging element unit 5 is inserted into a hole 21a in the upper housing 2 and joined to the upper housing 2 with screws, an adhesive, or the like (not shown). An imaging element thermal conductive member 13 is laminated behind the imaging element unit 5. The imaging element thermal conductive member 13 is a rubber-like material such as silicone, and is in the form of a thin film.

[0047] The imaging element thermal conduction member 13 is laminated on the rear surface of the imaging element substrate 10 and is in contact with the front wall portion 41 of the rear housing 4, and conducts heat generated by the imaging element 9. The heat received by the front wall portion 41 of the rear housing 4 is dissipated from the rear wall portion .

[0048] The main body substrate 6 is in the form of a flat plate extending in the front-rear and left-right directions. The main body substrate 6 is joined to a boss portion of the upper wall portion 22 of the upper housing 2 by fastening parts such as screws 7. The main body substrate 6 may also be joined to the lower housing 3.

[0049] The main body substrate 6 has a plurality of electronic components on its upper and lower surfaces. The main body substrate 6 and the image sensor substrate 10 are electrically connected via wiring 12. The plurality of electronic components arranged on the main body substrate 6 include a camera control IC 11. The camera control IC 11 controls the entire image capture device 1 in an integrated manner.

[0050] An upper surface heat conductive member 15 is laminated on the upper surface of the main body substrate 6. The upper surface heat conductive member 15 is a thin film made of a rubber-like material such as silicone. The upper surface heat conductive member 15 is in contact with at least a part of the multiple electric components including the camera control IC 11.

[0051] The upper surface heat conduction member 15 is in contact with the underside of the upper wall portion 22 of the upper housing 2, and conducts heat from the electronic components. The heat received by the underside of the upper wall portion 22 of the upper housing 2 is dissipated from the upper side of the upper wall portion 22.

[0052] A bottom heat conductive member 14 is laminated on the bottom surface of the main substrate 6. The bottom heat conductive member 14 is a thin film made of a rubber-like material such as silicone. The bottom heat conductive member 14 is in contact with at least some of the multiple electric components.

[0053] The bottom heat conductive member 14 is in contact with the upper side of the lower housing 3 and conducts heat from the electronic components. The lower housing 3 receives the heat conducted from the bottom heat conductive member 14 at its upper side and dissipates the heat from the lower side of the lower housing 3. Note that the main body board 6 and the upper wall portion 22 of the upper housing 2 shown in FIG. 4 are disposed below the lens unit 8, but may be disposed above the lens unit 8.

[0054] Next, a description will be given of the operation and effect of the imaging device 1 of this embodiment. As described above, in the imaging device 1 of this embodiment, the wide-angle lens 84 (hereinafter also referred to as the first optical system) located closest to the subject (windshield) has a special shape, not a perfect circle, when viewed from the optical axis direction (X-axis direction).

[0055] 7(A) to 7(F) are external views and perspective views, respectively, as viewed from the optical axis direction, for explaining examples of various shapes of wide-angle lens 84. In the example of Fig. 7(A), the upper end of circular wide-angle lens 84 is linearly notched (cut) so that the upper end of wide-angle lens 84 in the Z+ direction is cut in a straight line in the Y-axis direction. The notched (cut) portion is formed by cutting, polishing, or molding the circular wide-angle lens.

[0056] As a result, as shown in Fig. 7(A), the wide-angle lens 84 has a D-shape when viewed from the optical axis direction (X-axis direction). That is, in the example of Fig. 7(A), the first optical system has an arc-shaped portion with a predetermined radius and a straight-line portion drawn horizontally at the upper end when viewed from the optical axis direction.

[0057] In the example of Figure 7 (B), the upper end of a circular wide-angle lens 84 of a predetermined radius is cut out in an arc shape, so that the upper end of the wide-angle lens 84 in the Z+ direction is connected in the Y-axis direction by a curve with a curvature different from the circular shape.

[0058] 7(B), when viewed from the optical axis direction (X-axis direction), the radius of the arc at the upper end of wide-angle lens 84 in the Z+ direction is larger than the radius of the arc (predetermined radius) at the lower end of wide-angle lens 84 in the Z- direction. As a result, wide-angle lens 84 has a substantially D-shape with an upper side cut out in an arc shape when viewed from the optical axis direction (X-axis direction).

[0059] That is, in the example of Figure 7 (B), the first optical system has a circular portion of a predetermined radius when viewed from the optical axis direction, and an arc-shaped portion at the upper end of the first optical system having a radius larger than the predetermined radius.

[0060] 7(C), the upper end of the circular wide-angle lens 84 is cut out in an arc shape, so that the upper end of the wide-angle lens 84 in the Z+ direction is cut out in a straight line in the Y-axis direction, and the cutout surface is inclined in the depth direction (X-axis direction). In other words, the surface of the straight-line or arc-shaped portion on the upper end side of the wide-angle lens 84 may be inclined forward of the optical axis. This is to match the surface of the slanted windshield.

[0061] In Figures 7 (A) to (C), the upper end of the circular wide-angle lens 84 is cut out in an arc shape, so that when the YZ cross section of the wide-angle lens 84 (the projection surface when viewed from the optical axis direction) is divided into upper and lower sections by a straight line parallel to the Y axis passing through the center of the optical axis, the area of ​​the upper cross section is smaller than the area of ​​the lower cross section.

[0062] In other words, when the wide-angle lens 84 is viewed from the optical axis direction, the area of ​​the projection surface (YZ cross section) on the vertically upward side from the center of the optical axis is smaller than the area of ​​the projection surface on the vertically downward side. In other words, when the wide-angle lens 84 is viewed from the optical axis direction, the length in the vertical direction (direction parallel to the Z axis) passing through the center of the optical axis is shorter than the length in the horizontal direction (direction parallel to the Y axis) passing through the center of the optical axis.

[0063] In the example of Figure 7 (D), the upper and lower ends of the circular wide-angle lens 84 are each cut out in a straight line, so that the upper end of the wide-angle lens 84 in the Z+ direction is cut out in a straight line in the Y-axis direction, and the lower end in the Z- direction is cut out in a straight line in the Y-axis direction.

[0064] In this way, the first optical system may have circular portions (left and right portions) of a predetermined radius when viewed from the optical axis direction, and horizontally extending straight lines provided at the upper and lower ends of the first optical system.

[0065] Also, the first optical system may have the notched portions on the arc shown in the example of Fig. 7(B) at both the upper and lower ends as shown in the example of Fig. 7(D). Similarly, the first optical system may have the notched portions on the arc shown in the example of Fig. 7(C) at both the upper and lower ends as shown in the example of Fig. 7(D).

[0066] 7(E), the upper end, lower end, left end, and right end of the circular wide-angle lens 84 are each cut out linearly. As a result, both ends of the wide-angle lens 84 in the Z+ direction and the Z- direction are cut out linearly in the Y-axis direction, and both ends of the wide-angle lens 84 in the Y+ direction and the Y- direction are cut out linearly in the Z direction. That is, the first optical system has a substantially rectangular shape when viewed from the optical axis direction.

[0067] In Fig. 7(E), the corners of the rectangle are cut out to round the corners. In this way, it is desirable to have cutouts at the ends of the straight line or arc-shaped parts with a radius larger than a given radius in the horizontal direction. This is to allow the part to fit the curved surface of the windshield.

[0068] In the example of Fig. 7(F), the upper end of the circular wide-angle lens 84 is linearly cut out, so that the end of the wide-angle lens 84 in the Z+ direction is cut out in a straight line in the Y-axis direction, similar to Fig. 7(A). Furthermore, a staircase-like step is formed at the end of the cutout surface in the Y-axis direction.

[0069] The step as shown in Fig. 7(F) may be formed in the examples shown in Fig. 7(B) to (F) in the same manner. In this way, a step-like step may be formed at the end of the part having a straight line shape in the horizontal direction or an arc shape having a radius larger than the predetermined radius. This is to better match the curved shape of the windshield.

[0070] By making the wide-angle lens 84 have a shape as shown in the examples of Figures 7(A) to (F), the radius of the wide-angle lens 84 to the end in the Z+ direction can be made shorter than the radius of the circular shape (perfect circle shape) before being cut out.

[0071] That is, in this embodiment, in the first optical system of the lens unit 8, which is closest to the subject, the distance from the optical axis center to the end closest to the windshield is made shorter than the maximum diameter of the first optical system. Here, the maximum diameter of the first optical system refers to the maximum distance from the optical axis center to the end of the cross section in the YZ cross section of the first optical system shown in Figures 7(A) to 7(C).

[0072] Therefore, at least the upper end side of the wide-angle lens 84 can be made smaller than when the wide-angle lens 84 is a perfect circular lens. In addition, as shown in Fig. 6, the upper portion of the pressing ring 85 that covers the end of the wide-angle lens 84 in the Z+ direction can also be made smaller in the same manner.

[0073] FIG. 8(A) is a diagram showing an example in which an imaging device 1 according to an embodiment of the present invention is placed near the upper part of a vehicle's windshield (front windshield 103), and FIG. 8(B) is a diagram showing, for comparison, an example in which an imaging device equipped with a circular wide-angle lens is placed.

[0074] As shown in FIG. 8(A), the imaging device 1 of this embodiment can be placed closer to the front windshield 103 in the optical axis direction than the imaging device of FIG. 8(B) in which a circular wide-angle lens is arranged.

[0075] As a result, when comparing the angle of view of the imaging device 1 in Figures 8(A) and (B) with the lengths a, b between the contact points in the vertical direction of the front windshield 103, it can be seen that the length a in Figure 8(A) can be made smaller than the length b in Figure 8(B).

[0076] Figure 9 is a diagram showing an example of the angle of view and the contact points of the windshield in Figures 8(A) and 8(B) when viewed from the optical axis direction. a is the length between the contact points in the vertical direction shown in Figure 8(A), and b is the length between the contact points in the vertical direction shown in Figure 8(B). As shown in Figure 9, the area of ​​the region enclosed by the angle of view and the contact points of the windshield in Figure 8(A) can be made smaller than that in Figure 8(B).

[0077] Therefore, according to the imaging device 1 of this embodiment, the area of ​​the windshield within the angle of view can be reduced, so that the influence of windshield distortion can be reduced, and the influence of dirt, etc. adhering to the windshield can also be reduced.

[0078] In particular, in a device that measures the distance to a subject based on a signal acquired using a lens unit, distortion caused by the windshield has a significant effect on the measurement accuracy. Therefore, the imaging device 1 shown in this embodiment can reduce the influence of distortion caused by the windshield and obtain good distance measurement results.

[0079] In the above embodiment, a CMOS image sensor is used as the imaging element 9, but a sensor such as a CCD (Charge-Coupled Device) image sensor may also be used.

[0080] There are no particular limitations on the materials used for upper housing 2, lower housing 3, rear housing 4, lens barrel 81, spacer 83, and retainer ring 85. Preferably, they are made of a material with high thermal conductivity, such as a metal such as aluminum, copper, zinc, or iron, or an alloy made by mixing a plurality of metals.

[0081] Furthermore, the materials of the imaging element heat conductive member 13, the lower surface side heat conductive member 14, and the upper surface side heat conductive member 15 are not particularly limited. For example, silicone, graphite, etc. may be used. Also, a hardening material made by mixing two liquid materials, a non-hardening material such as grease, etc. may be used. Also, the shapes of the wide-angle lens 84 shown in Figures 7(A) to (F) may be appropriately combined.

[0082] Figures 10(A) to (C) are diagrams for explaining the relationship between image size 91 and image circle 92 of an imaging device according to an embodiment of the present invention. Figure 10(A) is a diagram showing a case where a typical lens having a perfect circle shape is used as wide-angle lens 84. Figures 10(B) and 10(C) are diagrams showing a case where, for example, the lens shown in Figure 7(A) is used as wide-angle lens 84.

[0083] It can be seen that the image circle 92 in Figures 10(B) and 10(C) is formed in a D-shape due to the shape of the lens in Figure 7(A). Note that the size of the image circle 92 in Figure 10(B) is smaller than that in Figure 10(A), but the image size 91 fits inside the image circle 92.

[0084] 10C shows a state in which an image size 91 extends beyond an image circle 92, causing vignetting 93, but in the imaging device according to the embodiment of the present invention, even if some vignetting 93 occurs, the effect of the vignetting 93 can be removed by image processing. Therefore, this embodiment may have a configuration in which vignetting as shown in FIG. 10C occurs.

[0085] Although the present invention has been described in detail based on the preferred embodiment, the present invention is not limited to the above embodiment, and various modifications are possible based on the spirit of the present invention, and are not excluded from the scope of the present invention. The above embodiment includes the following combinations.

[0086] (Configuration 1) An imaging device that is placed inside the windshield of a moving body and captures the outside of the moving body through the windshield, the imaging device having a lens unit for forming an optical image of the subject on a light receiving surface of an imaging element, and characterized in that in a first optical system of the lens unit that is closest to the subject, the distance from the optical axis to the end closest to the windshield is shorter than the maximum diameter of the first optical system.

[0087] (Configuration 2) The imaging device according to configuration 1, further comprising a calculation section that calculates a distance to a subject based on a phase difference between signals from a plurality of pixels of the imaging element.

[0088] (Configuration 3) An imaging device as described in configuration 1 or 2, characterized in that the first optical system has, on a projection plane when viewed from the optical axis direction, a portion that is an arc-shaped portion of a predetermined radius, and a portion that is a straight line at an upper end of the first optical system.

[0089] (Configuration 4) An imaging device described in any one of configurations 1 to 3, characterized in that the first optical system has a portion that is arc-shaped with a predetermined radius on a projection plane when viewed from the optical axis direction, and a portion that is arc-shaped with a radius larger than the predetermined radius at an upper end of the first optical system.

[0090] (Configuration 5) The imaging device according to configuration 3, wherein the surface of the linear or arc-shaped portion is inclined in a forward direction of the optical axis.

[0091] (Configuration 6) The imaging device according to any one of configurations 1 to 5, wherein the first optical system has a substantially rectangular shape on a projection surface when viewed from the optical axis direction.

[0092] (Configuration 7) The imaging device according to configuration 3, wherein a notch is formed at an end of the linear portion in the horizontal direction or the arc portion having a radius larger than the predetermined radius.

[0093] (Configuration 8) The imaging device according to configuration 3, wherein a step-like difference is formed at an end of the linear portion in the horizontal direction or the arc-shaped portion having a radius larger than the predetermined radius. [Explanation of symbols]

[0094] 1: Imaging device 2: Upper case 3: Lower housing 4: Rear housing 5: Image sensor unit 6: Main board 8: Lens unit 9: Image sensor 10: Image sensor board 11: Camera control IC 13: Thermal conductive material for image sensor 14: Bottom heat conductive material 15: Upper heat conductive member 21: Front wall 22: Upper wall part 23: Right side wall 24: Left side wall 25: Front wall 26: Upper wall 31: Flat part 41: Front wall 42: Rear wall part 81: Telescope tube 82: Lens 83: Spacer 84: Wide-angle lens 85: Presser ring 91: Image size 92: Image Circle 93: Vignetting 100:Vehicle 101: Bracket 102: Bracket 103: Front windshield 104: Route generation ECU 105: Vehicle control device 106: Drive unit 107: Measuring instruments, etc.

Claims

1. An imaging device that is disposed inside a windshield of a moving body and captures an image of the outside of the moving body through the windshield, a lens unit for forming an optical image of a subject on a light receiving surface of an image sensor; An imaging device characterized in that, in a first optical system of the lens unit closest to the subject, the distance from the optical axis to the end closest to the windshield is shorter than the maximum diameter of the first optical system.

2. 2. The imaging apparatus according to claim 1, further comprising a calculation unit that calculates a distance to a subject based on a phase difference between signals from a plurality of pixels of the imaging element.

3. The first optical system has, on a projection plane when viewed from the optical axis direction, a portion that is an arc shape having a predetermined radius; a linear portion at an upper end of the first optical system; 2. The imaging device according to claim 1, further comprising:

4. The first optical system has, on a projection plane when viewed from the optical axis direction, a portion that is an arc shape having a predetermined radius; an arc-shaped portion having a radius larger than the predetermined radius at an upper end of the first optical system; 2. The imaging device according to claim 1, further comprising:

5. 4. The imaging device according to claim 3, wherein a surface of the linear or arcuate portion is inclined in a forward direction of the optical axis.

6. 2. The imaging device according to claim 1, wherein the first optical system has a substantially rectangular shape on a projection surface when viewed in the optical axis direction.

7. 4. The imaging device according to claim 3, wherein a notch is formed at an end of the linear portion in the horizontal direction or the arc portion having a radius larger than the predetermined radius.

8. 4. The imaging device according to claim 3, wherein a step-like difference is formed at an end of the linear portion in the horizontal direction or the arc-shaped portion having a radius larger than the predetermined radius.

Images