Imaging device, vehicle lamp system, and imaging lens

Abstract

The invention relates to an imaging device, a vehicle lamp system, and an imaging lens, which can suppress the reduction of imaging precision caused by the center deviation of the incident position of light relative to the central axis of the imaging lens and the reduction of the number of light receiving elements for receiving light. An imaging device is provided with: an imaging element having a light receiving surface on which a plurality of light receiving elements are arranged; and an imaging lens that transmits light from the outside and forms light spots on the light receiving surface of the imaging element. The light-receiving surface of the imaging element is disposed at a position offset in the central axis direction of the imaging lens with respect to the light-focusing position of the imaging lens. The area of a first spot formed on the light receiving surface by light incident parallel to the central axis of the imaging lens to an arbitrary position in a target region from the center of the imaging lens to a predetermined distance in the radial direction is the same as the area of a basic spot formed on the light receiving surface by light incident parallel to the central axis of the imaging lens to the central axis.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a camera, a vehicle light system, and a camera lens. Background Art

[0002] For example, a photographing device that is mounted on a vehicle and photographs an object in front of the vehicle (e.g., a vehicle in front, an oncoming vehicle, a pedestrian, etc.) is known (e.g., see Patent Document 1 and Patent Document 2). The photographing device includes: a photographing element having a light receiving surface on which a plurality of light receiving elements are arranged; and a photographing lens that transmits light from the outside to form a light spot on the light receiving surface of the photographing element. The light receiving surface of the photographing element is arranged to coincide with the focal position of the photographing lens.

[0003] In addition, the image data captured by the camera is used, for example, in ADB (Adaptive Driving Beam) control for improving the lighting effect of the area in front of the vehicle. The ADB control is a control that determines whether there is an object in the area in front based on the image data captured by the camera, and changes the light distribution pattern of the vehicle's lighting device according to the determination result.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-70294

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-882234 Summary of the invention

[0008] Problems to be solved by the invention

[0009] In conventional photographing devices, as described above, the light-receiving surface of the photographing element is configured to coincide with the focal position of the photographing lens. Therefore, there is a risk that the photographing accuracy of the photographing device will be reduced due to a reduction in the number of light-receiving elements that receive light from relatively small objects such as the taillights of a vehicle at a long distance (e.g., 100 m). In addition, there is the following risk: in conventional photographing devices, when light from an object is incident on the central axis of the photographing lens, and when light from an object is incident on a position deviating from the central axis of the photographing lens, the area of ​​the light spot on the light-receiving surface changes significantly, and the photographing accuracy of the photographing device changes due to this change.

[0010] In addition, such problems are not limited to imaging devices mounted on mobile objects such as vehicles, but are also common to imaging devices that are fixedly arranged.

[0011] In this specification, a technology capable of solving at least a part of the above-mentioned problems is disclosed.

[0012] Means used to solve problems

[0013] The technology disclosed in this specification can be implemented as the following aspects, for example.

[0014] (1) The imaging device disclosed in the present specification comprises: an imaging element having a light receiving surface on which a plurality of light receiving elements are arranged; and an imaging lens which transmits light from the outside and forms a light spot of the light on the light receiving surface of the imaging element, wherein the light receiving surface of the imaging element is arranged at a position deviated in the central axis direction of the imaging lens relative to the focusing position of the imaging lens, and an area of ​​a first light spot formed on the light receiving surface by light incident on any position of an object area radially from the center of the imaging lens to a predetermined distance in parallel with the central axis of the imaging lens is the same as an area of ​​a basic light spot formed on the light receiving surface by light incident on the central axis in parallel with the central axis of the imaging lens.

[0015] In the present photographing device, the light receiving surface of the photographing element is arranged at a position deviated in the central axis direction of the photographing lens relative to the focusing position of the photographing lens. Therefore, in the present photographing device, compared with a configuration in which the light receiving surface of the photographing element is arranged at the focusing position of the photographing lens, since the area of ​​the light spot (image) formed on the light receiving surface is large, a large number of light receiving elements can receive light. Furthermore, in the present photographing device, the area of ​​the first light spot of light incident on any position of the object area of ​​the photographing lens is the same as the area of ​​the basic light spot of light incident on the central axis of the photographing lens. Therefore, in the present photographing device, the change in the area of ​​the light spot on the light receiving surface caused by the light incident on a position deviated from the central axis of the photographing lens is suppressed. Therefore, according to the present photographing device, the reduction in shooting accuracy caused by the deviation of the incident position of light relative to the central axis of the photographing lens (hereinafter referred to as "center deviation") and the reduction in the number of light receiving elements receiving light can be suppressed.

[0016] (2) In the above-mentioned imaging device, the following configuration may be adopted: the area of ​​the second light spot formed on the light receiving surface by light incident on any position of the object area of ​​the imaging lens at a predetermined angle relative to the central axis of the imaging lens is equal to the area of ​​the basic light spot. According to this imaging device, it is possible to suppress the reduction in imaging accuracy caused by the inclination of the imaging lens relative to the light receiving surface and the reduction in the number of light receiving elements receiving light.

[0017] (3) In the above-mentioned photographing device, the following configuration may be adopted: the area of ​​the third light spot formed on the light receiving surface by the light incident on the photographing lens that is arranged deviated within a predetermined range relative to the reference position on the central axis of the photographing lens is the same as the area of ​​the basic light spot. According to this photographing device, it is possible to suppress the reduction in photographing accuracy caused by the deviation of the arrangement of the photographing lens on the central axis and the reduction in the number of light receiving elements that receive light.

[0018] (4) In the above-mentioned photographing device, the following configuration may be adopted: the radius of curvature of the lens surface on the light-receiving surface side of the photographing lens increases as it approaches the peripheral side of the lens surface. According to this photographing device, the characteristic shape of the lens can suppress the reduction in photographing accuracy caused by the deviation of the center of the photographing lens and the reduction in the number of light-receiving elements receiving light.

[0019] (5) In the above-mentioned photographing device, the light receiving surface may be arranged at a position that is more deviated toward the photographing lens side than the light focusing position. According to the photographing device, for example, compared with a configuration in which the light receiving surface is arranged on the opposite side of the photographing lens relative to the light focusing position, the amount of light received by the light receiving surface is high, and thus a decrease in photographing accuracy can be more effectively suppressed.

[0020] (6) In the above-mentioned vehicle light system, the following configuration may be adopted: a vehicle light system mounted on a mobile body, the vehicle light system comprising: the above-mentioned imaging device for imaging an object existing outside the mobile body; and a vehicle light unit for controlling the vehicle light in a manner capable of changing the light distribution pattern of the vehicle light based on the position information of the object captured by the imaging device. According to the vehicle light system, it is possible to suppress the reduction of the imaging accuracy of the imaging device and control the light distribution pattern of the vehicle light with high accuracy.

[0021] (7) The photographing lens disclosed in this specification is a photographing lens arranged to face the light receiving surface of the photographing element in the photographing device, wherein the radius of curvature of the lens surface on the light receiving surface side of the photographing lens increases toward the peripheral side of the lens surface. According to the photographing lens, the change in the area of ​​the light spot on the light receiving surface caused by light incident on a position deviating from the central axis of the photographing lens is suppressed.

[0022] In addition, the technology disclosed in this specification can be implemented in various ways, for example, it can be implemented by a shooting device, a shooting lens, a shooting method, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is an explanatory diagram showing a running state of a motorcycle 1 equipped with the front camera 100 according to the embodiment.

[0024] Figure 2 This is an explanatory diagram showing the structure of the front camera 100 and the light point P on the light receiving surface 132 .

[0025] Figure 3 This is an explanatory diagram showing the performance evaluation results when the parallel incident light L is made incident on the imaging lens 110 .

[0026] Figure 4 This is an explanatory diagram showing the performance evaluation results when oblique incident light L is made incident on the imaging lens 110 .

[0027] Description of Reference Numerals

[0028] 1: Motorcycle;

[0029] 3A, 3B: Motor vehicles;

[0030] 4A, 4B: taillights;

[0031] 100: front camera;

[0032] 110: shooting lens;

[0033] 112: exit surface;

[0034] 113: spherical surface;

[0035] 114: incident surface;

[0036] 120: outer cover glass;

[0037] 130: shooting element;

[0038] 132: light receiving surface;

[0039] 134: light receiving element;

[0040] 140: image processing circuit;

[0041] 200: Headlight;

[0042] 300: Vehicle ECU;

[0043] 310: object detection unit;

[0044] 320: headlight control unit;

[0045] 330: camera control unit;

[0046] C: central axis;

[0047] P: light spot. DETAILED DESCRIPTION

[0048] A. Implementation method:

[0049] A-1. The structure of the motorcycle 1 having a front camera 100:

[0050] Figure 1 This is an explanatory diagram showing a running state of a motorcycle 1 equipped with the front camera 100 according to the present embodiment. Figure 1 A state where a motorcycle (two-wheeled vehicle) 1 and two motor vehicles (four-wheeled vehicles) 3A and 3B are traveling on a road H is shown. Figure 1 The mutually orthogonal XYZ axes for determining the direction are shown. In this specification, for convenience, the positive direction of the Z axis is referred to as the "upward direction", the negative direction of the Z axis is referred to as the "downward direction", the positive direction of the X axis is referred to as the "front direction", and the negative direction of the X axis is referred to as the "rear direction", but the front camera 100 can actually be set to a direction different from the above directions.

[0051] The motorcycle 1 is traveling behind two motor vehicles 3A and 3B. The motorcycle 1 and the motor vehicles 3A and 3B may be configured with an engine as a driving source, an electric motor as a driving source, or both an engine and an electric motor as driving sources. The motorcycle 1 is an example of a mobile body.

[0052] The motorcycle 1 includes a front camera 100, a headlight 200, and a vehicle ECU 300. The front camera 100 is disposed on the front side of the motorcycle 1 and is configured to capture an image of the area in front of the motorcycle 1. Figure 1 In the embodiment, the front camera 100 is arranged at a position different from the headlight 200, but it may be arranged near the headlight 200, or may be built in the headlight 200. The front camera 100 is an example of a photographing device, and the headlight 200 is an example of a vehicle light unit. In addition, the front camera 100, the headlight 200, and the vehicle ECU 300 constitute an example of a vehicle light system.

[0053] The headlamp 200 is configured to be able to change the light distribution pattern from the vehicle lamp. Specifically, the headlamp 200 includes, for example, a high beam unit capable of ADB control.

[0054] The vehicle ECU 300 includes an object detection unit 310, a light control unit 320, and a camera control unit 330. The object detection unit 310 performs image analysis on an image captured by the front camera 100 to detect an object. The light control unit 320 generates a light control signal for controlling the lighting and light distribution of the headlight 200 based on the detected object, and outputs the light control signal to the headlight 200. In addition, the vehicle ECU 300 performs ADB control for changing the light distribution pattern from the headlight 200 according to the position of the object (motor vehicle 3A, motor vehicle 3B, etc.) detected by the object detection unit 310. The camera control unit 330 controls the front camera 100.

[0055] A-2. Composition of the front camera 100:

[0056] Figure 2 1 is an explanatory diagram showing the structure of the front camera 100 and the light point P on the light receiving surface 132. Figure 2 As shown, the front camera 100 includes a photographing lens 110 , a cover glass 120 , an imaging element 130 , and an image processing circuit 140 .

[0057] The imaging element 130 has a planar light receiving surface 132. On the light receiving surface 132, a plurality of light receiving elements 134 are arranged in a matrix. Figure 2 The arrangement state of the light receiving elements 134 in the X1 portion which is a part of the light receiving surface 132 is shown.

[0058] The imaging element 130 is a color sensor, and the plurality of light receiving elements 134 include, for example, an R light receiving element 134R that receives light of a red component, a G light receiving element 134G that receives light of a green component, and a B light receiving element 134B that receives light of a blue component. In addition, the R light receiving element 134R includes, for example, a photoelectric conversion element (for example, a photodiode), and a color filter that is arranged in front of the photoelectric conversion element (in the positive direction of the X axis) and allows light of a red component to pass. The G light receiving element 134G includes, for example, a photoelectric conversion element, and a color filter that is arranged in front of the photoelectric conversion element and allows light of a green component to pass. The B light receiving element 134B includes, for example, a photoelectric conversion element, and a color filter that is arranged in front of the photoelectric conversion element and allows light of a blue component to pass.

[0059] like Figure 2 As shown in the X1 portion of , a plurality of R light receiving elements 134R, a plurality of G light receiving elements 134G, and a plurality of B light receiving elements 134B are arranged in a matrix, and each R light receiving element 134R, each G light receiving element 134G, and each B light receiving element 134B is configured to be adjacent to each other.

[0060] The imaging lens 110 is disposed in front of the light receiving surface 132 of the imaging element 130. The imaging lens 110 transmits light L from the outside and forms a light spot P of the light L on the light receiving surface 132. The imaging lens 110 may be made of glass or resin.

[0061] The cover glass 120 is disposed between the imaging lens 110 and the light receiving surface 132 of the imaging element 130. The cover glass 120 protects the imaging lens 110 and the like.

[0062] The vehicle ECU 300 sequentially acquires the electrical signals output from the light receiving elements 134 of the imaging element 130 , performs predetermined image processing (RGB color conversion, etc.) based on the electrical signals, and outputs the imaging data to the vehicle ECU 300 .

[0063] A-3. Composition of the photographing lens 110:

[0064] In this embodiment, the positional relationship between the imaging lens 110 and the imaging element 130 satisfies the following first condition.

[0065] <First condition>

[0066] The light receiving surface 132 of the imaging element 130 is arranged at a position offset in the direction of the central axis C of the imaging lens 110 (X-axis direction) with respect to the light focusing position of the imaging lens 110 .

[0067] In the present embodiment, the photographing lens 110 is a single lens, and therefore the light-collecting position of the photographing lens 110 is the focal position of the photographing lens 110 .

[0068] Thus, the light receiving surface 132 of the imaging element 130 is offset from the focusing position of the imaging lens 110, so that the light incident through the center of the imaging lens 110 and parallel to the central axis C forms a light spot P on the light receiving surface 132 that includes the size of the plurality of light receiving elements 134 (refer to Figure 2 X1 part). In the present embodiment, the light spot P has a size including 5×5 pixels (light receiving element), but may also be a size including 7×7 pixels, or may also be a size including 9×9 pixels. In addition, in the direction of the central axis C, the deviation of the position of the light receiving element 134 relative to the focusing position (hereinafter referred to as "central axial deviation") is preferably less than 5% of the focusing distance (the focal length from the shooting lens 110 to the focusing position). In addition, the upper limit of the central axial deviation may be less than 5% of the focusing distance, less than 4% of the focusing distance, or less than 2% of the focusing distance.

[0069] In this embodiment, the photographing lens 110 satisfies the following second condition.

[0070] <Second Condition>

[0071] The area of ​​the light spot P (first light spot) formed on the light receiving surface 132 by the light L (hereinafter referred to as "parallel incident light L") incident on any position of the object area of ​​the shooting lens 110 parallel to the central axis C of the shooting lens 110 is the same as the area of ​​the basic light spot.

[0072] The object area refers to the area from the central axis C to the position at a predetermined distance radially outward in the incident surface 114 of the shooting lens 110. The object area can be the entire incident surface 114, but in the present embodiment, it can also be a part of the incident surface 114 (the area excluding the peripheral portion of the incident surface 114). The basic light point is the light point formed on the light receiving surface 132 by the parallel incident light L incident on the central axis C. In short, no matter where the parallel incident light L is incident on the object area of ​​the shooting lens 110, the light point P on the light receiving surface 132 includes multiple light receiving elements 134 and has the same area.

[0073] In addition, in this specification, "the same area as the basic light spot" is not limited to the case where the area is completely the same as the basic light spot, but also includes an area within an error range of ±20% relative to the area of ​​the basic light spot. In addition, the error range relative to the area of ​​the basic light spot is preferably within ±15%, more preferably within ±10%, and further preferably within ±5%.

[0074] In the present embodiment, the imaging lens 110 satisfies the following third condition.

[0075] <Third Condition>

[0076] The area of ​​the light spot P (second light spot) formed on the light receiving surface 132 by the light L (hereinafter referred to as "inclined incident light L") which is incident on any position of the object area of ​​the shooting lens 110 at a predetermined angle (for example, within an angular range of 0° to 30.3°) relative to the central axis C is the same as the area of ​​the basic light spot.

[0077] In the present embodiment, the photographing lens 110 satisfies the following fourth condition.

[0078] <Fourth condition>

[0079] The area of ​​the light spot P (third light spot) formed on the light receiving surface 132 by the light L incident on the shooting lens 110 is the same as the area of ​​the basic light spot, and the shooting lens 110 is deviated from the reference position (for example, the focusing position) within a predetermined range in the direction of the central axis C of the shooting lens 110.

[0080] In the present embodiment, the imaging lens 110 satisfies the following fifth condition.

[0081] <Fifth Condition>

[0082] The curvature radius of the lens surface (light-emitting surface 112 ) on the light-receiving surface 132 side of the imaging lens 110 increases toward the peripheral side of the light-emitting surface 112 .

[0083] Specifically, the exit surface 112 of the photographing lens 110 is an aspherical surface. Figure 2 The curvature of the curved surface becomes gradually slower as it moves toward the peripheral side. Thus, the error between the area of ​​the light spot P of the light L incident at any position of the target area from any angle and the area of ​​the reference light spot can be effectively reduced.

[0084] Incident surface 114 of imaging lens 110 is also aspherical. Central portion 114A including central axis C of incident surface 114 is convex, and peripheral portion 114B around central portion 114A is concave. In this embodiment, the central portion is the target area.

[0085] In this embodiment, the positional relationship between the imaging element 130 and the imaging lens 110 satisfies the following sixth condition.

[0086] <Sixth Condition>

[0087] The light receiving surface 132 of the imaging element 130 is arranged at a position deviated from the light focusing position of the imaging element 130 toward the imaging lens 110 side (X-axis positive direction).

[0088] Specifically, it is preferable that the photographing lens 110 satisfies both the following lens condition 1 and lens condition 2.

[0089] Lens condition 1: The lens has a characteristic that the refractive power (power to bend light) of the lens remains substantially constant even when light rays having different principal ray angles are incident.

[0090] Lens condition 2: The lens has a characteristic in which the bending force is weak at the center of the lens (the incident pupil coordinate is 0) and maintains a local maximum value at the incident pupil coordinate of 0.8, and the optical power becomes weak again as the incident pupil coordinate becomes 1 (the end of the lens).

[0091] For example, when the optical power at the pupil coordinate position x (-1≤x≤1) when the principal ray angle is θ° is set to P θ (X), the photographing lens 110 satisfies the following conditions in the central portion 114A of the incident surface 114:

[0092] 1.16≥P 30° (0) / P 0° (0)≥1

[0093] 1.16≥P 30° (0.65) / P0° (0.65)≥1.

[0094] The photographing lens 110 satisfies the following conditions in the exit surface 112:

[0095] 1.00≥P 30° (0) / P 0° (0)≥0.99

[0096] 1.00≥P 30° (0.9) / P 0° (0.9)≥0.89.

[0097] A-4. Performance evaluation of the front camera 100:

[0098] The performance evaluation of the front camera 100 was performed using a photographing lens 110 with the following specifications:

[0099] F-number: 1.4

[0100] Effective diameter of lens: 2.4mm

[0101] Focal length: 3.8mm.

[0102] A-4-1. Performance evaluation when parallel incident light L is incident on the photographing lens 110:

[0103] Figure 3 This is an explanatory diagram showing the performance evaluation results when the parallel incident light L is made incident on the imaging lens 110 . Figure 3 The horizontal axis represents the position deviation distance of the light receiving surface 132 relative to a predetermined reference position (eg, the focal position of the shooting lens 110) in the direction of the central axis C (a positive distance is the distance to a position further rearward than the focal position). Figure 3 The vertical axis represents the number of light receiving elements (pixels) whose intensity of received light is above a reference level. The reference level is the level of light intensity that is changed into a voltage signal of a predetermined level by photoelectric conversion in each light receiving element (for example, 0.02). For example, "25" on the vertical axis means that 25 light receiving elements arranged in 5×5 received light above the reference level. The curve G1 represented by a solid line is the number of light received by the light spot P (basic light spot) when parallel incident light L passes through the central axis C of the imaging element 130 (hereinafter referred to as the "central light receiving number"), and the curve G2 represented by a dotted line is the number of light received by the light spot P when parallel incident light L passes through the peripheral part of the object area of ​​the imaging element 130 (hereinafter referred to as the "peripheral light receiving number").

[0104] according to Figure 3According to the evaluation result, if the deviation (defocus) in the direction of the central axis C is at least within the range of ±150μm relative to the reference position, the number of central light receptions is consistent with the number of peripheral light receptions. This means that when the parallel incident light L is incident on any position of the object area of ​​the shooting element 130, the first condition, the second condition, and the fourth condition are satisfied by the front camera 100, thereby ensuring the area of ​​the light spot P in the light receiving surface 132 to a large extent and the area becomes the same. In addition, when the position deviation distance of the light receiving surface 132 is outside the above range, it is believed that the reduction in the number of peripheral light receptions is due to the light distribution deviation in the peripheral part of the shooting lens 110.

[0105] A-4-2. Performance evaluation when oblique incident light L is incident on the photographing lens 110:

[0106] Figure 4 This is an explanatory diagram showing the performance evaluation results when oblique incident light L is incident on the imaging lens 110. Figure 3 same, Figure 4 The horizontal axis represents the position deviation distance of the light receiving surface 132, Figure 4 The vertical axis represents the number of light receiving elements (pixels) whose intensity of received light is above the reference level. The curve G3 represented by the solid line is the number of central light receiving points of the light spot P when the oblique incident light L passes through the central axis C of the imaging element 130, and the curve G4 represented by the dotted line is the number of light receiving points of the light spot P when the oblique incident light L passes through a position at a predetermined distance (e.g., 312 μm) from the central axis C of the imaging element 130 (hereinafter referred to as the "eccentric light receiving point"). In addition, the incident angle of the oblique incident light L relative to the central axis C is 2.1 degrees.

[0107] according to Figure 4 According to the evaluation result, if the deviation (defocus) in the direction of the central axis C is at least in the range of -80μm to +170μm, the number of central light receptions is consistent with the number of eccentric light receptions. This means that when the oblique incident light L is incident on any position of the object area of ​​the shooting element 130, the first condition, the third condition, and the fourth condition mentioned above are satisfied by the front camera 100, thereby ensuring the area of ​​the light spot P in the light receiving surface 132 to a large extent and the area becomes the same. In addition, when the position deviation distance of the light receiving surface 132 is outside the above range, it is believed that the reduction in the number of central light receptions and the number of eccentric light receptions is due to the light distribution deviation in the peripheral portion of the shooting lens 110.

[0108] A-5. Effects of this embodiment:

[0109] As described above, in the front camera 100 of the present embodiment, the light receiving surface 132 of the imaging element 130 is arranged at a position deviated from the light focusing position of the imaging lens 110 in the direction (X-axis direction) away from the central axis C of the imaging lens 110 (first condition). Therefore, in the present embodiment, for example, in a configuration in which the light receiving surface 132 of the imaging element 130 is arranged at the light focusing position of the imaging lens 110, compared with a case in which light of the same beam width is incident on the imaging lens 110, the area of ​​the light spot P (image) formed on the light receiving surface 132 is large, so that a large number of light receiving elements 134 can receive light.

[0110] In addition, in the present embodiment, the area of ​​the light spot P (first light spot) formed on the light receiving surface 132 by the parallel incident light L incident on any position of the target area of ​​the photographing lens 110 is the same as the area of ​​the basic light spot (second condition). Therefore, the change in the area of ​​the light spot P on the light receiving surface 132 caused by the light L incident on the position deviating from the center axis C of the photographing lens 110 is suppressed. Therefore, according to the present embodiment, the reduction in photographing accuracy caused by the deviation of the incident position of the light L from the center axis C of the photographing lens 110 (hereinafter referred to as "center deviation") and the reduction in the number of light receiving elements 134 receiving light can be suppressed.

[0111] exist Figure 1 In the example, the motor vehicle 3A and the motor vehicle 3B are photographed from behind by the front camera 100 of the motorcycle 1. When the distance between the motor vehicle 3A, the motor vehicle 3B and the motorcycle 1 is long (for example, more than 100 mm), the taillights 4A and 4B of the motor vehicle 3A and the motor vehicle 3B are regarded as extremely small point light sources. Therefore, for example, in the configuration in which the light receiving surface 132 of the shooting element 130 is arranged at the focusing position of the shooting lens 110 (comparative example), the red light from the taillights 4A and 4B is focused by the shooting lens 110, and there is a risk of forming an extremely small light spot including only one light receiving element on the light receiving surface. When the small light spot is located at the G light receiving element 134G or the B light receiving element 134B, in the comparative example, the taillights 4A and 4B cannot be photographed (detected). In addition, when the tiny light spot is located between the R light receiving element 134R and the light receiving elements 134G and 134B of other colors, the light intensity in the R light receiving element 134R is low, so the tail lights 4A and 4B cannot be photographed in the comparative example.

[0112] In contrast, in the front camera 100 of the present embodiment, Figure 2As shown in the X1 part of , the light spot P in the light receiving surface 132 is a size including 5×5 pixels (light receiving element), so the tail lights 4A and 4B can be photographed. In addition, when the red light from the tail lights 4A and 4B is incident on any position of the target area of ​​the shooting lens 110, the area of ​​the light spot P formed on the light receiving surface 132 is the same as the area of ​​the basic light spot. Therefore, the tail lights 4A and 4B can be effectively photographed. When the object detection unit 310 detects the tail lights 4A and 4B, the vehicle light control unit 320 changes to a light distribution pattern that partially blocks the high beam of the headlight 200.

[0113] In this embodiment, the area of ​​the light spot P (second light spot) formed on the light receiving surface 132 by the oblique incident light L incident on any position of the target area of ​​the photographing lens 110 is the same as the area of ​​the basic light spot (third condition). According to this embodiment, it is possible to suppress the reduction in photographing accuracy caused by the inclination of the photographing lens 110 relative to the light receiving surface 132 and the reduction in the number of light receiving elements 134 receiving light.

[0114] In the present embodiment, the area of ​​the light spot P (third light spot) formed on the light receiving surface 132 by the light L incident on the photographing lens 110 is the same as the area of ​​the basic light spot (fourth condition), and the photographing lens 110 is arranged to be deviated within a predetermined range relative to the reference position in the direction of the central axis C of the photographing lens 110. According to the present embodiment, it is possible to suppress a reduction in photographing accuracy caused by a deviation in the arrangement of the photographing lens 110 in the direction of the central axis C and a reduction in the number of light receiving elements 134 that receive light.

[0115] The light receiving surface 132 of the imaging element 130 is arranged at a position that is offset from the light focusing position of the imaging element 130 to the imaging lens 110 side (X-axis positive direction) (sixth condition). According to this embodiment, for example, compared with a configuration in which the light receiving surface 132 is arranged on the opposite side of the imaging lens 110 with respect to the light focusing position, the amount of light received (light intensity) on the light receiving surface is high, so that a decrease in imaging accuracy can be more effectively suppressed.

[0116] B. Modifications:

[0117] The technology disclosed in this specification is not limited to the above-mentioned embodiment, and can be modified into various aspects within the scope not departing from the gist thereof. For example, the following modifications are also possible.

[0118] The front camera 100 and other structures in the above-mentioned embodiment are only examples and can be modified in various ways. For example, in the above-mentioned embodiment, the shooting lens 110 is a single lens, but it can also be a composite lens composed of multiple lenses. In the case of a composite lens, the "focusing position" is the position where the light passing through the multiple lenses is most focused.

[0119] In the above embodiment, as a shooting element, a shooting element 130 including an R light receiving element 134R, a G light receiving element 134G and a B light receiving element 134B is exemplified. The shooting element may be a shooting element having light receiving elements of any two colors among the R light receiving element 134R, the G light receiving element 134G and the B light receiving element 134B, or may be a black and white shooting element including only light receiving elements of one color.

[0120] In the above embodiment, the front camera 100 may be configured to not satisfy at least one of the second to sixth conditions. In addition, the shape of the shooting lens 110 may not satisfy the fifth condition, and the shape of the shooting lens 110 may be configured to satisfy the second to fourth conditions.

[0121] In the above-mentioned embodiment, the material forming each member is just an example, and it can also be formed with other materials.

[0122] In the above embodiment, as a photographing device, a front camera 100 mounted on the motorcycle 1 is exemplified, but it may also be a photographing device mounted on the side, rear, etc. of the motorcycle 1. In addition, the photographing device may be mounted on other two-wheeled vehicles (bicycles, etc.), or may be mounted on other moving bodies (four-wheeled vehicles, aircraft, etc.). Furthermore, the photographing device may be mounted on a fixed body (e.g., a monitoring device, traffic infrastructure, etc.). In addition, the image data captured by the photographing device may be used for purposes other than ADB control (e.g., automatic driving of moving bodies, etc.).

Claims

1. A photographing device comprising: a photographing element having a light receiving surface on which a plurality of light receiving elements are arranged; and a photographing lens which transmits light from the outside and forms a light spot of the light on the light receiving surface of the photographing element, wherein: The light receiving surface of the imaging element is arranged at a position offset in the central axis direction of the imaging lens relative to the focusing position of the imaging lens. The area of ​​the first light spot formed on the light receiving surface by light incident on any position of the object area radially from the center of the shooting lens to a predetermined distance parallel to the central axis of the shooting lens is the same as the area of ​​the basic light spot formed on the light receiving surface by light incident on the central axis parallel to the central axis of the shooting lens.

2. The photographing device according to claim 1, wherein: The area of ​​a second light spot formed on the light receiving surface by light incident on an arbitrary position of the target area of ​​the photographing lens at a predetermined angle relative to the central axis of the photographing lens is equal to the area of ​​the basic light spot.

3. The photographing device according to claim 1 or 2, wherein: The area of ​​a third light spot formed on the light receiving surface by light incident on the photographing lens arranged to be offset within a predetermined range from a reference position in the central axial direction of the photographing lens is the same as the area of ​​the basic light spot.

4. The photographing device according to claim 1 or 2, wherein: The curvature radius of the lens surface on the light receiving surface side of the imaging lens increases toward the peripheral edge side of the lens surface.

5. The photographing device according to claim 1 or 2, wherein: The light receiving surface is arranged at a position deviated from the light focusing position toward the imaging lens.

6. A vehicle lighting system, mounted on a moving object, wherein: The vehicle light system comprises: Headlights; The imaging device according to claim 1, which captures an object existing outside the moving body; and A vehicle lamp unit is controlled so as to be able to change a light distribution pattern of the vehicle lamp based on the position information of the object captured by the imaging device.

7. An imaging lens arranged to face a light receiving surface of an imaging element in an imaging device, The curvature radius of the lens surface on the light receiving surface side of the imaging lens increases toward the peripheral edge side of the lens surface.

Images