Imaging device and in-vehicle system

Abstract

To enable a small imaging device to easily reduce variations in focus caused by temperature change.SOLUTION: An imaging device includes: a lens barrel that holds a plurality of lenses 104a and 104b; an imaging element 115 that images an object through the plurality of lenses; and a holding member 105 that holds the imaging element and the lens barrel. The lens barrel is configured by combining a plurality of partial lens barrels 101 and 102 that respectively holds the lenses. The holding member holds any among the plurality of partial lens barrels in a holding section 108 further toward the object than the lens, closest to an image side, among the plurality of lenses. A linear expansion coefficient of at least one partial lens barrel among the plurality of partial lens barrels is different from linear expansion coefficients of the other partial lens barrels.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an imaging device used in an in-vehicle camera or the like.

Background Art

[0002] In an in-vehicle camera, there is a high need to reduce focus fluctuations due to expansion and contraction of a lens, a lens barrel that holds the lens, and further a holding member that holds the lens barrel and an imaging element as the temperature changes. Patent Document 1 discloses an imaging device that reduces focus fluctuations accompanying temperature changes by making the materials (that is, the linear expansion coefficients) of a plurality of holding members that hold the lenses different from each other. Further, Patent Document 2 discloses an imaging device that reduces focus fluctuations accompanying temperature changes by making the materials of the lens barrel and the holding member different from each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the imaging device of Patent Document 1, it is necessary to adjust the distances between each lens and the imaging element, respectively, and the manufacturing process becomes complicated. Further, by providing a holding member for each lens, the imaging device becomes larger in the lens diameter direction.

[0005] Further, in the imaging device of Patent Document 2, since focus fluctuations are reduced only by the selection of the materials of the lens barrel and the holding member, the selection range of the materials becomes narrow or the selection itself becomes difficult.

[0006] The present invention provides an imaging device that is small but can easily reduce focus fluctuations accompanying temperature changes. [Means for solving the problem]

[0007] According to the present invention, the imaging device comprises a lens barrel that holds a plurality of lenses, an image sensor that images an object through the plurality of lenses, and a holding member that holds the image sensor and the lens barrel. The lens barrel is composed of a plurality of partial lens barrels that each hold a lens, which are joined together. The holding member holds one of the plurality of partial lens barrels at a holding portion closer to the object than the lens that is closest to the image. The invention is characterized in that the coefficient of linear expansion of at least one of the plurality of partial lens barrels is different from the coefficient of linear expansion of the other partial lens barrels. An in-vehicle system including the above imaging device also constitutes one aspect of the present invention. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an imaging device that is compact yet can easily reduce focus fluctuations due to temperature changes. [Brief explanation of the drawing]

[0009] [Figure 1] A cross-sectional view showing the camera configuration of Example 1. [Figure 2] A diagram illustrating the sign of Pdn / dT in Example 1. [Figure 3] A cross-sectional view showing the camera configuration of Example 2. [Figure 4] Functional block diagram of the in-vehicle system of Example 3. [Figure 5] A schematic diagram of a vehicle equipped with the above-mentioned in-vehicle system. [Figure 6] A flowchart illustrating the operation of the above-mentioned in-vehicle system. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Examples]

[0011] FIG. 1 shows a cross-section along the optical axis 103 of a camera as an imaging device according to Embodiment 1 of the present invention. The camera of this embodiment is composed of partial lens barrels 101 and 102, a plurality of lenses 104a and 104b, an imaging element 115, a substrate 107, a holding member 105, and a spacing adjustment member 106. The camera of this embodiment can be used as an in-vehicle camera, a camera for a mobile terminal, or other imaging devices.

[0012] The plurality of lenses 104a and 104b are arranged along the direction in which the optical axis 103 extends (hereinafter referred to as the optical axis direction) to form an imaging optical system.

[0013] The partially formed lens barrels 101 and 102 are joined so that they are connected in the optical axis direction to form an integral lens barrel. Specifically, the outer peripheral portion on the image side of the object-side lens barrel (hereinafter referred to as the object-side lens barrel) 101 and the inner peripheral portion on the object side of the image-side lens barrel (hereinafter referred to as the image-side lens barrel) 102 are joined to each other at the joining portion 109 by adhesion or screw connection.

[0014] The object-side lens barrel 101 holds the plurality of lenses 104a, and the image-side lens barrel 102 holds the plurality of lenses 104b. A plane orthogonal to the optical axis direction between the lens holding portion that holds the lens 104a on the most image side in the object-side lens barrel 101 and the lens holding portion that holds the lens 104b on the most object side in the image-side lens barrel 102 is defined as the lens barrel dividing surface 111.

[0015] The spacing adjustment member 106 is disposed in the object-side lens barrel 101 and the image-side lens barrel 102 to adjust and hold the spacing in the optical axis direction between the plurality of lenses 104a and the spacing in the optical axis direction between the plurality of lenses 104b.

[0016] The imaging element 115 is mounted and held on the substrate 107. The imaging element 115 is composed of a CCD sensor or a CMOS sensor, and is a photoelectric conversion element that images an object (not shown) through an imaging optical system. The substrate 107 is held by the holding member 105 by being fixed to the image-side end of the holding member 105. The holding member 105 has the object-side lens barrel 101 screw-coupled to the holding portion 108 near its object-side end (on the object side of the most image-side lens in the imaging optical system), and is further adhered to hold the object-side lens barrel 101 (that is, the entire lens barrel). In the screw coupling of the object-side lens barrel 101 to the holding member 105, the screwing amount of the object-side lens barrel 101 with respect to the lens barrel holding member 105 at the holding portion 108 is adjusted so that the distance in the optical axis direction between the lens barrel (that is, the lenses 104a, 104b) and the imaging surface of the imaging element 115 becomes a predetermined distance. The preferable conditions for the distance 110 in the optical axis direction between the adjusted holding portion 108 and the imaging surface of the imaging element 115 to satisfy will be described later.

[0017] Let the linear expansion coefficient of the object-side lens barrel 101 be A, the linear expansion coefficient of the image-side lens barrel 102 be B, and the linear expansion coefficient of the holding member 105 be C. At this time, in this embodiment, they are set such that A < B and C < B. Specifically, for example, A = 1.5×10 -5 m / °C, B = 6.0×10 -5 m / °C, C = 1.8×10 -5 m / °C.

[0018] The temperature variation of the optical focus plane in this embodiment will be described. Let the variation amount of the focus plane due to the linear expansion (change in the lens surface shape) accompanying the temperature change of the plurality of lenses 104a, 104b be Ps. Also, let the variation amount of the focus plane due to the change in the refractive index accompanying the temperature change of the plurality of lenses 104a, 104b be Pdn / dT, and the number of the plurality of lenses 104a, 104b be k. At this time, for example, the total variation amount of the focus plane for a 1°C temperature rise is expressed by the following formula (1).

[0019]

Equation

[0020] Equation (1) shows the total change in the focal plane on the object side, calculated by summing the Ps and Pdn / dT values ​​for each of the lenses 104a and 104b. If this total change is positive, that is,

[0021]

number

[0022] In this case, as the temperature rises, the focal plane on the object side moves closer to the object (i.e., towards the back focus direction), and the focal plane on the image sensor side moves closer to the object relative to the image sensor.

[0023] In equations (1) and (2) above, the sign of Pdn / dT changes depending on the direction of increase or decrease of the refractive index change dn of the lens due to the temperature rise dT (sign of dn / dT) and whether the lens is a negative or positive lens, as shown in Figure 2. When the refractive index of a positive lens increases and the power of the positive lens increases, the focal plane on the image sensor side moves away from the image sensor (towards the object). Therefore, the sign of Pdn / dT becomes negative. Conversely, when the refractive index of a negative lens increases and the power of the negative lens increases, the focal plane on the image sensor side moves closer to the image sensor. Therefore, the sign of Pdn / dT becomes positive.

[0024] While the refractive index of typical lenses increases with temperature, some lenses used in automotive cameras have the characteristic of decreasing refractive index with increasing temperature. The sign of the Pdn / DT of a lens with such refractive index change characteristics is determined by the sign relationship shown in Figure 2.

[0025] On the other hand, the sign of Ps is determined by whether the lens is positive or negative. In a typical lens, the radial length is longer than the thickness, and when the lens expands due to rising temperature, the lens surface stretches radially, increasing the curvature of the lens surface. As a result, the power of the lens weakens, and if the lens is positive, it becomes front-focused, and the sign of Ps is positive. If the lens is negative, it becomes back-focused, and the sign of Ps is negative. If the coefficient of linear expansion, the curvature of the lens surface, the thickness of the lens in the optical axis direction, and the diameter of the lens are known, the value of Ps can be calculated.

[0026] In this embodiment, the total change in the focal plane due to the temperature rise is negative, i.e.,

[0027]

number

[0028] Let's assume this is the case. The suppression of temperature fluctuations at the focal plane in this case will be explained below.

[0029] Temperature fluctuations at the focal plane can be adjusted by the material (coefficient of linear expansion) of the object barrel 101, the image-side barrel 102, and the holding member 105, the distance 110 described above, and the setting of the barrel division surface 111. When the temperature of the entire camera rises from the temperature at which focusing was performed (for example, room temperature of 23°C) due to changes in ambient temperature, the holding member 105 expands linearly (stretches) according to its coefficient of linear expansion, causing the entire barrel to move toward the object side relative to the image sensor 115. In addition, the portion of the object-side barrel 101 closer to the object than the holding part 108 stretches toward the object side relative to the holding member 105, and the portion closer to the image than the holding part 108 stretches toward the image side relative to the holding member 105. Furthermore, the entire image-side barrel 102 moves toward the image side relative to the holding part 108.

[0030] As described above, in this embodiment, since the total amount of movement of the focus plane associated with the temperature rise is negative, while the focus plane on the imaging surface side moves toward the object side, the entire lens barrel moves toward the side closer to the imaging surface, canceling out the movement of the focus plane as a whole. In order to obtain a cancellation structure having such a cancellation effect of the temperature variation of the focus plane, it is a prerequisite that the holding portion 108 is on the object side of the most image-side lens in the imaging optical system. Further, it is desirable that the relationship of the linear expansion coefficients is A < B and C < B. This is due to the following reasons.

[0031] The image-side lens barrel 102 that moves closer to the imaging surface on the image side of the holding portion 108 approaches the imaging surface more when the linear expansion coefficient is larger than that of the holding member 105. On the other hand, by making the linear expansion coefficients of the holding member 105 and the object-side lens barrel 101 smaller than that of the image-side lens barrel 102, the entire lens barrel can be prevented from moving away from the imaging surface. Thereby, the entire lens barrel can be controlled to move in a direction closer to the imaging surface.

[0032] The lens barrel division surface 111 is most preferably set to coincide with the position of the holding portion 108. This is because, as described above, the lens barrel is divided into a direction approaching the imaging surface and a direction moving away from the imaging surface with the holding portion 108 as a boundary, and the closer the lens barrel division surface 111 is to the holding portion 108, the easier it is to obtain the cancellation structure described above.

[0033] However, due to restrictions on the optical arrangement of the lens and the holding configuration of the lens barrel, it may be difficult to make the lens barrel division surface 111 coincide with the position of the holding portion 108. In this case, if the distance 110 between the holding portion 108 and the imaging surface is L, a sufficient cancellation effect can be obtained by setting the lens barrel division surface 111 to a position within 0.5L from the holding portion 108. When the holding portion 108 has a length in the optical axis direction as in this embodiment, the distance L is the distance between the center in the optical axis direction of the holding portion 108 and the imaging surface. Note that 0.5L may be more preferably 0.3L, and even more preferably 0.1L.

[0034] Furthermore, it is desirable that L be greater than a predetermined length in order to obtain a cancellation effect. This is because, in this embodiment, the distance the lens barrel can be moved in the direction toward the imaging plane is (AB) × L, and therefore, the longer L is, the easier it is to obtain a cancellation effect. The absolute value of the total fluctuation amount of the focal plane shown in equation (1) is

[0035]

number

[0036] When ΔP is the distance, it is desirable to set (AB)×L to a distance that suppresses fluctuations in the focal plane, which corresponds to at least half of ΔP. That is, ΔP × 0.5 ≤ < (AB) × L It is desirable to set L such that the following conditions are satisfied. More preferably, ΔP × 0.7 ≤ < (AB) × L It is desirable to set L such that the following conditions are satisfied.

[0037] Next, the cancellation effect of temperature fluctuations at the focal plane in this embodiment will be explained in comparison with the comparative example. First, the distance L(110) required to theoretically eliminate the fluctuation at the focal plane for every 1°C of temperature fluctuation will be explained. The comparative example has the same configuration as shown in Figure 1, but the linear expansion coefficient of the object-side lens barrel is the same as that of the image-side lens barrel.

[0038] In this embodiment, the distance L is 16.7 mm. In contrast, in the comparative example, L = 20.0 mm is required to achieve zero calculated focus fluctuation. This is because the object-side lens barrel in the comparative example is further away from the imaging plane compared to the embodiment, weakening the effect of the lens barrel as a whole in returning the focal plane to the imaging plane. As a result, in order to suppress temperature fluctuations at the focal plane with high precision in the comparative example, the holding part of the retaining member must be configured to embrace the area closest to the object-side lens, which leads to a larger camera. Generally, the lens closest to the object often has a larger diameter to capture light from a wide imaging range. Also, since an outer casing is placed around the lens closest to the object, it is not suitable to place the holding part of the retaining member in this area. Furthermore, in this embodiment, it is possible to select a material with a large difference in linear expansion coefficient from among commonly used materials as the linear expansion coefficient of the retaining member 105 and the image-side lens barrel 102, but it is difficult to provide a larger difference in linear expansion coefficient than this. For this reason, in cameras with large temperature fluctuations at the focal plane, the configuration of the comparative example inevitably leads to a larger size. [Examples]

[0039] Figure 3 shows a cross-section along the optical axis 303 of the camera in Embodiment 2. The camera in this embodiment consists of an object-side lens barrel 301 and an image-side lens barrel 302, which are partial lens barrels, a plurality of lenses 304a and 304b, an image sensor 315, a substrate 307, a holding member 305, and a spacing adjustment member 306.

[0040] Multiple lenses 304a and 304b are arranged in the direction of the optical axis to form an imaging optical system. The object-side lens barrel 301 and the image-side lens barrel 302, which are formed by division, are joined together in the direction of the optical axis to form a single lens barrel. Specifically, the outer circumference on the image side of the object-side lens barrel 301 and the inner circumference on the object side of the image-side lens barrel 302 are joined to each other at the joint 309 by adhesive or screw connection.

[0041] The object-side lens barrel 301 holds multiple lenses 304a, and the image-side lens barrel 302 holds multiple lenses 304b. The lens barrel division surface 311 is defined as the plane perpendicular to the optical axis between the lens holding portion that holds lens 304a at the image-side end of the object-side lens barrel 301 and the lens holding portion that holds lens 304b at the object-side end of the image-side lens barrel 302.

[0042] The spacing adjustment member 306 is located inside the object-side lens barrel 301 and the image-side lens barrel 302 to adjust and maintain the spacing in the optical axis direction between multiple lenses 304a and between multiple lenses 304b.

[0043] An image sensor 315 mounted on a substrate 307 images an object (not shown) via an imaging optical system. The substrate 307 is held by a holding member 305 by being fixed to the image-side end of the holding member 305. The holding member 305 holds the object-side lens barrel 301, i.e., the entire lens barrel, by bonding the image-side end face of the flange portion of the object-side lens barrel 301 to a holding portion 308 at its object-side end (closer to the object than the image-side lens in the imaging optical system). At this time, the distance in the optical axis direction between the lens barrel (lenses 304a, 304b) and the imaging surface of the image sensor 315 is adjusted to a predetermined distance. The preferred conditions for the distance 310(L) in the optical axis direction between the adjusted holding portion 308 (in this embodiment, the surface bonded to the image-side end face of the flange portion of the object-side lens barrel 301) and the imaging surface of the image sensor 315 are the same as in Embodiment 1.

[0044] In this embodiment, the linear expansion coefficient A of the object-side lens barrel 301, the linear expansion coefficient B of the image-side lens barrel 302, and the linear expansion coefficient C of the holding member 305 are set such that A > B and C > B. Specifically, for example, A = 6.0 × 10 -5 m / ℃, B=1.5×10 -5 m / ℃, C=5.0×10 -5 The temperature is m / ℃.

[0045] Furthermore, in this embodiment, as shown in equation (2), the total change in the focal plane due to the temperature rise is assumed to be positive. In this case, contrary to Embodiment 1, as the temperature rises from the temperature at which the focus adjustment was performed, the focal plane on the imaging surface side moves closer to the imaging surface, while the entire lens barrel moves away from the imaging surface towards the object, thus canceling out the overall movement of the focal plane. At this time, it is desirable that the magnitude relationship of the coefficients of linear expansion be A > B and C > B, as mentioned above. This is for the following reasons.

[0046] The image-side lens barrel 302, which is on the image side of the holding portion 308, will be less likely to approach the imaging plane if its coefficient of thermal expansion is smaller than that of the holding member 305. On the other hand, the larger the coefficient of thermal expansion of the holding member 305 and the object-side lens barrel 301 is compared to that of the image-side lens barrel 302, the further the entire lens barrel will move away from the imaging plane towards the object. This allows the entire lens barrel to be controlled to move further away from the imaging plane.

[0047] If the total amount of change in the focal plane due to the temperature rise is positive, the entire lens barrel extends in a direction that naturally corrects the focus change, even without employing a cancellation structure that cancels the temperature change of the focal plane as in this embodiment. However, if the total amount of change in the focal plane is large, it is possible to suppress the focus change well by employing a cancellation structure to prevent the image-side lens barrel 302 from approaching the imaging plane.

[0048] In the above examples 1 and 2, the case in which the lens barrel is divided into two sub-lens barrels was described, but the number of divisions of the lens barrel may be three or more, and it is sufficient that the coefficient of thermal expansion of at least one of the sub-lens barrels is different from the coefficient of thermal expansion of the other sub-lens barrels.

[0049] Furthermore, in the above embodiments 1 and 2, the case was described in which the holding member holds the object-side lens barrel, which is the part of the lens barrel closest to the object among a plurality of part lens barrels, at the holding portion. However, it is also possible to hold a part lens barrel other than the part lens barrel closest to the object, such as the second part lens barrel from the object side among three or more part lens barrels, or the part lens barrel closest to the image among two or more part lens barrels. However, the holding portion must be on the object side of the lens closest to the image.

[0050] Furthermore, although this embodiment describes a case where the two partial lens barrels and the holding member all have different coefficients of thermal expansion, the coefficients of thermal expansion of the object-side lens barrel and the holding member may be the same. [Examples]

[0051] Figure 4 shows the configuration of the in-vehicle system (driving assistance device) 600 of Example 3, which uses the camera from Example 1 or Example 2 as an in-vehicle camera. The in-vehicle system 600 is held by a movable mobile body (mobile device) such as an automobile (vehicle) and is a system for assisting the driving (operation) of the vehicle based on image information of the surroundings of the vehicle acquired by the in-vehicle camera 10.

[0052] Figure 5 shows a vehicle 700 as a mobile device equipped with an on-board system 600. In Figure 5, the imaging range 50 of the on-board camera 10 is set to the front of the vehicle 700, but the imaging range 50 may also be set to the rear or side of the vehicle 700.

[0053] As shown in Figures 4 and 5, the in-vehicle system 600 includes an in-vehicle camera 10, a vehicle information acquisition device 20, a control device (control unit, ECU: electronic control unit) 30, and a warning device (warning unit) 40. The in-vehicle camera 10 also includes an imaging unit 1, an image processing unit 2, a parallax calculation unit 3, a distance acquisition unit (acquisition unit) 4, and a collision determination unit 5, as shown in Figure 4. The processing unit is composed of the image processing unit 2, the parallax calculation unit 3, the distance acquisition unit 4, and the collision determination unit 5. The imaging unit 1 has a lens unit of Embodiment 1 or 2 and an image sensor such as a CCD sensor or a CMOS sensor, and captures images of objects.

[0054] The flowchart in Figure 6 shows an example of the operation of the in-vehicle system 600. The in-vehicle system 600 (mainly the control device 30) executes this process according to the computer program.

[0055] First, in step S1, the imaging unit 1 is used to image objects (targets) such as obstacles and pedestrians around the vehicle, and multiple image data (disparity image data) are acquired.

[0056] In step S2, vehicle information is acquired by the vehicle information acquisition device 20. Vehicle information includes information such as the vehicle speed, yaw rate, and steering angle.

[0057] In step S3, the image processing unit 2 performs image processing on the multiple image data acquired by the imaging unit 1. Specifically, it performs image feature analysis to analyze feature quantities such as the amount and direction of edges and density values ​​in the image data. Here, image feature analysis may be performed on each of the multiple image data, or on only some of the multiple image data.

[0058] In step S4, the disparity calculation unit 3 calculates the disparity (image shift) information between multiple image data acquired by the imaging unit 1. Known methods such as the SSDA method and the area correlation method can be used to calculate the disparity information, so a detailed explanation is omitted here. Note that steps S2, S3, and S4 may be performed in the order described above, or they may be processed in parallel.

[0059] In step S5, the distance acquisition unit 4 acquires (calculates) distance information between the imaging unit 1 and the object it has imaged. The distance information can be calculated based on the parallax information calculated by the parallax calculation unit 3 and the internal and external parameters of the imaging unit 1. The distance information here refers to information about the relative position to the object, such as the distance to the object, the amount of defocus, and the amount of image displacement. This information may directly represent the distance value of the object in the image, or it may indirectly represent information corresponding to the distance value.

[0060] Then, in step S6, the collision determination unit 5 uses the vehicle information acquired by the vehicle information acquisition device 20 and the distance information calculated by the distance acquisition unit 4 to determine whether the distance to the target object is within a preset distance range. This allows the system to determine whether or not the target object is within the set distance around the vehicle and to determine the possibility of a collision between the vehicle and the target object. The collision determination unit 5 determines "possibility of collision" if the target object is within the set distance (step S7), and determines "no possibility of collision" if the target object is not within the set distance (step S8).

[0061] Next, if the collision determination unit 5 determines that there is a possibility of collision, it notifies (transmits) the determination result to the control device 30 and the warning device 40. At this time, the control device 30 controls the vehicle based on the determination result from the collision determination unit 5 (step S6), and the warning device 40 issues a warning to the vehicle user (driver, passengers) based on the determination result from the collision determination unit 5 (step S7). Note that notification of the determination result only needs to be made to at least one of the control device 30 and the warning device 40.

[0062] The control device 30 can control the movement of the vehicle by outputting control signals to the vehicle's drive unit (engine, motor, etc.). For example, it can control the vehicle by applying the brakes, releasing the accelerator, turning the steering wheel, and generating control signals to apply braking force to each wheel to suppress the output of the engine or motor. The warning device 40 can also warn the user by, for example, emitting a warning sound (alarm), displaying warning information on a screen such as a car navigation system, or vibrating the seat belt or steering wheel.

[0063] According to the in-vehicle system 600 of this embodiment, the above processing makes it possible to effectively detect objects and avoid collisions between the vehicle and objects. In particular, by applying the optical systems according to each embodiment described above to the in-vehicle system 600, it becomes possible to miniaturize the entire in-vehicle camera 10 and increase the degree of freedom in placement while performing object detection and collision detection over a wide field of view.

[0064] There are various methods for calculating distance information. As an example, we will describe the case where the imaging unit 1 employs a pupil-splitting type image sensor having multiple pixel sections arranged regularly in a two-dimensional array. In a pupil-splitting type image sensor, one pixel section is composed of a microlens and multiple photoelectric conversion units, and can receive a pair of light beams passing through different regions of the pupil of the optical system, and output a pair of image data from each photoelectric conversion unit.

[0065] Then, the amount of image displacement in each region is calculated by correlation calculation between paired image data, and the distance acquisition unit 4 calculates image displacement map data representing the distribution of the image displacement amounts. Alternatively, the distance acquisition unit 4 may further convert the image displacement amounts into defocus amounts and generate defocus map data representing the distribution of defocus amounts (distribution on a two-dimensional plane of the captured image). In addition, the distance acquisition unit 4 may acquire distance map data of the distance to the object converted from the defocus amounts.

[0066] Furthermore, the in-vehicle system 600 and the mobility device 700 may be equipped with a notification device (notification unit) to notify the manufacturer of the in-vehicle system or the dealer of the mobility device if the mobility device 700 collides with an obstacle. For example, the notification device may be one that sends information regarding the collision between the mobility device 700 and an obstacle (collision information) to a pre-set external notification destination via email or the like.

[0067] In this way, by adopting a configuration in which collision information is automatically notified by the notification device, it is possible to promptly take action such as inspection and repair after a collision occurs. The recipients of the collision information may be insurance companies, medical institutions, the police, or any other name set by the user. Furthermore, the notification device may be configured to notify recipients not only of collision information, but also of malfunction information of various parts and information on the wear and tear of consumables. The detection of whether or not a collision has occurred may be performed using distance information acquired based on the output from the light receiving unit 2 described above, or it may be performed by other detection units (sensors).

[0068] In this embodiment, the in-vehicle system 600 was applied to driver assistance (collision damage mitigation), but it is not limited to this, and the in-vehicle system 600 may also be applied to cruise control (including with full-speed following function) or autonomous driving. Furthermore, the in-vehicle system 600 is not limited to automobiles and other vehicles, but can be applied to mobile objects such as ships, aircraft, and industrial robots. Moreover, it is not limited to mobile objects, but can be applied to various devices that utilize object recognition, such as intelligent transportation systems (ITS). (Other examples) The present invention can also be realized by supplying a program that implements one or more of the functions of the above-described embodiments to a system or device via a network or storage medium, and by having one or more processors in the computer of that system or device read and execute the program. It can also be realized by a circuit (e.g., an ASIC) that implements one or more functions.

[0069] The embodiments described above are merely representative examples, and various modifications and changes can be made to each embodiment when implementing the present invention.

[0070] In the embodiment described above, the case in which the lens device is applied to an in-vehicle camera 10 as a distance measuring device was explained, but it may also be applied to in-vehicle cameras other than distance measuring devices. For example, the in-vehicle camera may be placed at the rear or side of the vehicle, and the acquired image information may be displayed on an in-vehicle display unit (monitor) to enable driving assistance. In this case, the parallax calculation unit, distance acquisition unit, collision determination unit, and other components used for distance measurement may not be provided.

[0071] Furthermore, while the above-described embodiment described the case in which the lens device is applied to the imaging unit in an in-vehicle system, it is not limited to this. For example, the lens device may be applied to imaging devices such as digital still cameras, digital video cameras, and silver halide film cameras, or to optical instruments such as telescopes or projection devices such as projectors. [Explanation of Symbols]

[0072] 101,301 Object-side microscope tube 102,302 Image side lens barrel 104a, 104b, 304a, 304b lenses 105,305 Retaining member 108,308 Holding part 115,315 image sensors

Claims

1. a lens barrel for holding a plurality of lenses; an imaging element that captures an image of an object through the plurality of lenses; a holding member that holds the image sensor and the lens barrel, the lens barrel is configured by combining a plurality of partial lens barrels each holding a lens, the holding member holds any one of the plurality of partial barrels at a holding portion that is closer to the object than the lens that is closest to the image side among the plurality of lenses, An imaging device, wherein at least one of the plurality of partial barrels has a coefficient of linear expansion different from the coefficients of linear expansion of the other partial barrels.

2. the plurality of partial barrels comprise an object-side barrel and an image-side barrel, Let Ps be the amount of variation of the focal plane due to linear expansion of the lens caused by a temperature change, Pdn / dT be the amount of variation of the focal plane due to a change in refractive index of the lens caused by a temperature change, k be the number of the plurality of lenses, A be the linear expansion coefficient of the object-side lens barrel, B be the linear expansion coefficient of the image-side lens barrel, and C be the linear expansion coefficient of the holding member. [Equation 1] A < B C<B 2. The imaging device according to claim 1, wherein the following condition is satisfied:

3. the plurality of partial barrels comprise an object-side barrel and an image-side barrel, Let Ps be the amount of variation of the focal plane due to linear expansion of the lens caused by a temperature change, Pdn / dT be the amount of variation of the focal plane due to a change in refractive index of the lens caused by a temperature change, k be the number of the plurality of lenses, A be the linear expansion coefficient of the holding member, B be the linear expansion coefficient of the object-side lens barrel, and C be the linear expansion coefficient of the image-side lens barrel. [Equation 2] A>B C>B 2. The imaging device according to claim 1, wherein the following condition is satisfied:

4. 4. The imaging device according to claim 2 or 3, wherein when the distance in the optical axis direction between the imaging surface of the imaging element and the holding portion is L, the distance in the optical axis direction between the lens holding portion closest to the image in the object-side barrel and the lens holding portion closest to the object in the image-side barrel and a barrel dividing surface perpendicular to the optical axis direction is 0.5L or less. [Request Item 5] [Number 3] is ΔP, and the distance in the optical axis direction between the imaging surface of the imaging element and the holding portion is L, 0.5×ΔP<L(AB) 5. The imaging device according to claim 2, wherein the following condition is satisfied:

6. 6. The imaging device according to claim 1, wherein the holding member holds the partial barrel closest to the object side among the plurality of partial barrels at the holding portion.

7. The imaging device according to any one of claims 1 to 6, and a processing unit that processes image information acquired by the imaging device.

8. 8. The in-vehicle system according to claim 7, further comprising a determination unit that determines the possibility of a collision between the vehicle and the object based on the image information.

9. 9. The in-vehicle system according to claim 8, further comprising a notification device that notifies an external device of information regarding a collision between the vehicle and the object.

10. A moving device comprising the imaging device according to claim 1 , and capable of moving while holding the imaging device.

11. The moving device according to claim 10, further comprising a determination unit that determines the possibility of a collision with the object based on image information acquired by the imaging device.

12. 12. The moving device according to claim 11, further comprising a control unit that outputs a control signal for controlling movement when it is determined that there is a possibility of collision with the object.

13. 13. The mobile device according to claim 11, further comprising a warning unit that issues a warning to a user of the mobile device when it is determined that there is a possibility of a collision with the object.

14. 14. The moving device according to claim 11, further comprising a notification unit that notifies an external device of information relating to the collision with the object.

Images