Lens unit, camera module, imaging system, and mobile body

Abstract

The present invention provides a lens unit, camera module, imaging system, and mobile body that can achieve a desired aperture without the need to arrange an aperture element between lenses and without providing an aperture function to the intermediate ring. [Solution] The lens unit 11 of the present invention comprises a lens group L in which a plurality of lenses 13-17 are arranged along the optical axis O of the lenses, a lens barrel 12 having an inner housing space S for housing and holding the lens group L, an aperture member 30 for adjusting the amount of light transmitted through the lens group L, and intermediate rings 20, 21, 22 interposed between the lenses constituting the lens group L. The aperture member 30 is incorporated into the intermediate ring 20 and fixed by adhesive.

Description

Technical Field

[0005] ,

[0001] The present invention particularly relates to a lens unit, a camera module, an imaging system, and a moving body equipped with the imaging system, which are components of an in-vehicle camera mounted on a vehicle such as an automobile.

Background Art

[0002] Conventionally, in-vehicle cameras have been mounted on automobiles to support parking or prevent collisions through image recognition, and attempts have also been made to apply them to autonomous driving. In addition, such a camera module, such as an in-vehicle camera, generally includes a lens unit having a lens group in which a plurality of lenses are arranged along an optical axis, a lens barrel (barrel) that houses and holds the lens group, and an aperture member that is disposed at at least one location of the lens group to adjust the amount of light (see, for example, Patent Document 1).

[0003] By the way, the aperture member, which is a component of the lens unit, is generally disposed in a state of being sandwiched between lenses or is formed by an intermediate ring that adjusts the interval between lenses in the optical axis direction (functioning the intermediate ring as an aperture).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the aperture member is disposed in a state of being sandwiched between lenses as described above, it is necessary to newly provide a support portion for supporting the aperture member. In that case, if the support portion is provided as a new support part, the number of parts increases, and if a support portion for supporting the aperture member is formed on the lens or the like, the shape of the lens or the like becomes complicated.

[0006] Furthermore, when molding an intermediate ring from resin to function as an aperture, for example, an edge is formed in the center of the intermediate ring to act as an aperture. However, due to the generation of burrs during molding, or because the edge cannot be formed in the desired shape, the intermediate ring may not function properly as an aperture. Moreover, such an intermediate ring with aperture functionality may even become a source of reflective ghosting.

[0007] Furthermore, if the aperture element or the intermediate ring with aperture function is thin, warping may occur, which could impair its function as an aperture.

[0008] The present invention has been made in view of the above circumstances, and aims to provide a lens unit, camera module, imaging system, and mobile body that can achieve a desired aperture without the need to arrange an aperture member between lenses and without providing an aperture function to the intermediate ring. [Means for solving the problem]

[0009] To solve the aforementioned problems, the present invention provides a lens unit comprising a lens group in which a plurality of lenses are arranged along the optical axis of the lenses, a lens barrel having an inner housing space for housing and holding the lens group, an aperture member for adjusting the amount of light transmitted through the lens group, and an intermediate ring interposed between the lenses constituting the lens group, wherein the aperture member is incorporated into the intermediate ring and fixed by adhesive bonding.

[0010] With the above configuration, the aperture member is incorporated into the intermediate ring and fixed by adhesive, meaning the intermediate ring itself supports the aperture member. Therefore, there is no need to sandwich the aperture member between the lenses, and consequently, there is no need to provide a new support part to support the aperture member, nor is there a need to form a support part on the lens to support the aperture member. As a result, the desired aperture can be achieved without increasing the number of parts or complicating the shape of the lens. Furthermore, since there is no need for the intermediate ring itself to function as an aperture, there is no need to mold the intermediate ring into an aperture shape. This eliminates the risk of the aperture function being impaired due to molding defects, the intermediate ring becoming a source of reflection ghosting, and the risk of the aperture function being impaired due to warping of the thinned intermediate ring when adding the aperture function.

[0011] Furthermore, in the above configuration of the present invention, the intermediate ring may have a recess for incorporating and accommodating an aperture member. This allows the aperture member to be easily incorporated into the intermediate ring. In this case, it is preferable that the aperture member is arranged so as to fit completely within the recess of the intermediate ring. This avoids limiting the degree of freedom in optical design by incorporating the aperture member.

[0012] Furthermore, in the above configuration of the present invention, it is preferable that the recess is defined inward by the inner surface of the intermediate ring, which holds the outer surface of the aperture member and positions the aperture member coaxially with the optical axis. This allows the aperture member to be supported and the optical axis aligned solely by the recess.

[0013] Furthermore, in the above configuration of the present invention, it is preferable that the intermediate ring has an adhesive application portion to which an adhesive for bonding the aperture member to the intermediate ring is applied. In this case, it is preferable that the adhesive application portion is formed as a concave notch on the inner circumferential surface of the intermediate ring, forming an adhesive reservoir that allows the adhesive to be applied across the gap between the aperture member and the intermediate ring. With this, the aperture member can be reliably bonded and fixed to the intermediate ring simply by applying adhesive to the adhesive application portion.

[0014] Furthermore, in the above configuration of the present invention, it is preferable that a step is formed on the radially inner edge of the annular bottom surface of the recess. With this, the adhesive that has spread from the adhesive application area to the back surface of the aperture member (the annular surface of the aperture member that contacts the bottom surface of the recess of the intermediate ring) flows down to the step, so that the adhesive does not continue to flow radially inward across the back surface of the aperture member. Therefore, the adhesive that flows out from the adhesive application area does not adversely affect the aperture function.

[0015] Furthermore, the present invention also provides a camera module having the aforementioned lens unit, an imaging system having the camera module, and a mobile body equipped with the imaging system. The same effects and advantages as those of the aforementioned lens unit can be obtained with such a camera module, imaging system, and mobile body. The term "mobile body" refers to all objects that can be moved, such as vehicles. [Effects of the Invention]

[0016] According to the present invention, a desired aperture can be achieved without the need to arrange an aperture member between lenses, and without providing an aperture function to the intermediate ring. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic cross-sectional view of a lens unit according to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic cross-sectional view of a camera module according to one embodiment of the present invention, which includes a lens unit. [Figure 3] This is a perspective view of an intermediate ring formed by incorporating a diaphragm member. [Figure 4] (a) is a front view of the intermediate ring, and (b) is a cross-sectional view along line AA of (a). [Figure 5] This is a front view of the diaphragm member. [Figure 6] This is a schematic diagram of a vehicle as a mobile body on which an imaging system (in-vehicle system) equipped with a camera module according to one embodiment of the present invention is mounted. [Figure 7]It is a block diagram showing the configuration of an imaging device that constitutes the imaging system of FIG. 6.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment contributes to "9. Build the foundation of industry and technological innovation" among the Sustainable Development Goals (SDGs) proposed by the United Nations. Note that the lens unit of the present embodiment described below is particularly for a camera module such as an in-vehicle camera. For example, it is fixedly installed on the outer surface side of an automobile, and the wiring is drawn into the automobile and connected to a display or other devices. Also, in FIGS. 1 and 2, hatching is omitted for the lenses.

[0019] FIG. 1 shows a lens unit 11 according to an embodiment of the present invention. As shown in the figure, the lens unit 11 of the present embodiment includes, for example, a cylindrical lens barrel (barrel) 12 made of resin, and a plurality of lenses arranged in an inner accommodation space S of the lens barrel 12, for example, from the object side, a first lens 13, a second lens 14, a third lens 15, a fourth lens 16, and a fifth lens 17, a single aperture member 30, and three annular intermediate rings 20, 21, and 22. The aperture member 30 is an "aperture stop" that limits the amount of transmitted light and determines the F value that is an indicator of brightness, or a "light shielding stop" that shields light rays that cause ghosts or light rays that cause aberrations. The first intermediate ring 20 holds the aperture member 30 and is inserted between the first lens 13 and the second lens 14 via a spacer 19. The second intermediate ring 21 holds the second lens 14 inside and is inserted between the second lens 14 and the third lens 15 via a spacer 19. The third intermediate ring 22 is inserted between the fourth lens 16 and the fifth lens 17 that are concavo-convexly fitted to the third lens 15 via a spacer 19. An in-vehicle camera including such a lens unit 11 includes the lens unit 11, a substrate having an image sensor (imaging element) not shown in the figure, and an installation member not shown in the figure for installing the substrate on a vehicle such as an automobile.

[0020] The plurality of lenses 13, 14, 15, 16, and 17 incorporated and housed in the inner accommodation space S of the lens barrel 12 are stacked and arranged in a state where their respective optical axes are aligned, and are arranged in a state where the lenses 13, 14, 15, 16, and 17 are arranged along a single optical axis O, constituting a group of lens groups L used for imaging. In this case, the first lens 13 located on the most object side of the lens group L is formed as a convex surface whose surface 13b is convex toward the object side, and the back surface 13b facing the second lens 14 forms a concave surface that forms a cavity recessed toward the inside of the lens, and is a spherical glass lens. The second lens 14 held by the second intermediate ring 21 is also a glass lens, and the other lenses 15, 16, and 17 are resin lenses, but are not limited thereto.

[0021] Furthermore, the surfaces of these lenses 13, 14, 15, 16, and 17 may be coated with an anti-reflective coating, a hydrophilic coating, a water-repellent coating, or the like, as needed.

[0022] Furthermore, in this embodiment, an O-ring 26 is interposed between the first lens 13, which is located closest to the object, and the lens barrel 12, to prevent water and dust from entering the lens group L inside the lens barrel 12. In this case, a stepped diameter reduction portion 13d is provided on the outer circumferential surface 13c of the first lens 13, where the diameter is smaller on the image side of the lens 13. The O-ring 26 is fitted onto this diameter reduction portion 13d, and the O-ring 26 is compressed radially between the outer circumferential surface 13c of the first lens 13 and the inner circumferential surface 12a of the lens barrel 12, thereby sealing the object-side end of the lens barrel 12. Note that the sealing member interposed between the first lens 13 and the lens barrel 12 is not limited to an O-ring, but can be any form of annular body that can seal the space between the first lens 13 and the lens barrel 12.

[0023] Furthermore, with the lens group L assembled and housed within its inner housing space S, the first lens 13, which is located closest to the object in the lens group L, is fixed to the object-side end of the lens barrel 12 in the optical axis direction by the crimping portion 23 at the object-side end (upper end in Figure 1) of the lens barrel 12, which is thermally crimped radially inward. In this case, to ensure stable crimping, the portion of the glass lens 13 to which the crimping portion 23 is pressed is formed as a flat portion cut diagonally in a planar shape. Note that the means for fixing the first lens 13 to the object-side end of the lens barrel 12 in the optical axis direction is not limited to such a crimping portion 23. For example, if the lens barrel 12 is made of metal, the first lens 13 may be fixed to the object-side end of the lens barrel 12 in the optical axis direction by a cap that is screwed onto the object-side end of the lens barrel 12.

[0024] Furthermore, an inner flange portion 29 is provided at the image-side end (lower end in Figure 1) of the lens barrel 12, having an opening smaller in diameter than the fifth lens 17, which is located closest to the image in the lens group L. This inner flange portion 29 and the crimping portion 23 hold and fix the multiple lenses 13, 14, 15, 16, 17 constituting the lens group L, the aperture member 30, and the intermediate rings 20, 21, 22 in the optical axis direction within the lens barrel 12. In addition, an infrared cut filter 99 is attached to the mounting surface of the inner flange portion 29 that faces the image side, opposite to the support surface 29a that supports the fifth lens 17.

[0025] Figure 2 is a schematic cross-sectional view of the camera module 300 of this embodiment, which has a lens unit 11 configured as described above. As shown in the figure, the camera module 300 includes an upper case (camera case) 301, which is an exterior component, and a mount (base) 302 that holds the lens unit 11. The camera module 300 also includes a sealing member 303 and a package sensor (image sensor) 304.

[0026] The upper case 301 engages with a flange portion 25 provided in a flange shape on the outer circumferential surface 12b of the lens barrel 12, and is a member that exposes the object-side end of the lens unit 11 and covers the other part. The mount 302 is located inside the upper case 301 and has a female thread 302a that screws into the male thread 11a of the lens unit 11. The sealing member 303 is a member interposed between the inner surface of the upper case 301 and the outer circumferential surface 12b of the lens barrel 12 of the lens unit 11, and is a member that maintains airtightness inside the upper case 301.

[0027] The package sensor 304 is positioned inside the mount 302, facing the infrared cut filter 99, and is located in a position to receive the image of an object formed by the lens unit 11. The package sensor 304 also includes a CCD or CMOS sensor and converts the light collected and reaching it through the lens unit 11 into an electrical signal. The converted electrical signal is then converted into analog or digital data, which are components of the image data captured by the camera.

[0028] As described above, the first intermediate ring 20 holds an aperture member 30 for adjusting the amount of light transmitted through the lens group L. In this case, the aperture member 30 is formed in an annular shape from a light-opaque material (in this embodiment, a metal such as SUS) as shown in Figure 5, and has an opening 30a for allowing light to pass through and an outer peripheral surface 30b, and is incorporated into and bonded to the first intermediate ring 20. Specifically, as shown in Figure 4, the first intermediate ring 20 has a recess 42 on its object-side surface 20d for incorporating and accommodating the aperture member 30. This recess 42 communicates with a through hole 20c that penetrates the image-side surface 20e of the first intermediate ring 20, and is defined on the inside of the first intermediate ring 20 by the object-side inner peripheral surface 20a of the first intermediate ring 20. Furthermore, the recess 42 has an annular bottom surface 42a that supports the annular back surface (the annular surface facing the image side) of the aperture member 30. This bottom surface 42a extends radially inward from the inner circumferential surface 20a so as to form an opening 20f on the inside, which has an inner diameter larger than the inner diameter of the opening 30a of the aperture member 30, and communicates with the through hole 20c through this opening 20f. The through hole 20c is defined inward by the image-side inner circumferential surface 20b of the first intermediate ring 20, which extends diagonally radially inward from the image-side surface 20e of the first intermediate ring 20 to the periphery of the opening 20f.

[0029] As shown in Figures 1 to 3, the diaphragm member 30 is arranged to fit completely within the recess 42 of the first intermediate ring 20. In this embodiment, the diaphragm member 30 is formed from a single sheet, but multiple sheet-like diaphragm members 30 may be stacked and housed in the recess 42. In this case, multiple diaphragm members 30 with different inner diameters are stacked so that the inner diameter gradually decreases toward the center in the thickness direction of the stack. Furthermore, the diaphragm member 30 may be formed to a predetermined thickness by such stacking, giving the diaphragm member 30 the function of an intermediate ring.

[0030] Furthermore, in this embodiment, the inner circumferential surface 20a on the object side of the first intermediate ring 20 that defines the recess 42 holds (fits with) the outer circumferential surface 30b of the aperture member 30, thereby positioning the aperture member 30 coaxially with the optical axis O.

[0031] Furthermore, the first intermediate ring 20 has an adhesive application section 40 to which adhesive is applied for bonding the diaphragm member 30 to the first intermediate ring 20. In this embodiment, three adhesive application sections 40 are provided on the inner circumferential surface 20a of the first intermediate ring 20 at 120-degree angular intervals along its circumferential direction, but the number and placement of the adhesive application sections 40 are not limited thereto. Specifically, the adhesive application section 40 is formed on the inner circumferential surface 20a of the first intermediate ring 20 as a semicircular concave notch that forms an adhesive reservoir so that adhesive is applied between the diaphragm member 30 and the first intermediate ring 20.

[0032] Furthermore, in this embodiment, a step 50 is formed on the radially inner edge of the annular bottom surface 42a of the recess 42 of the first intermediate ring 20. This step 50 is formed to allow the radially inner edge of the bottom surface 42a to escape toward the image side so as not to come into contact with the aperture member 30. As a result, the adhesive that has flowed from the adhesive application area 40 to the back surface of the aperture member 30 (the annular surface of the aperture member 30 that comes into contact with the bottom surface 42a of the recess 42 of the first intermediate ring 20) flows down to the step 50, so that the adhesive does not continue to flow radially inward across the back surface of the aperture member 30. Therefore, the adhesive that flows out from the adhesive application area 40 does not adversely affect the aperture function.

[0033] Figure 6 schematically shows a vehicle 240 as a mobile body on which an in-vehicle system (imaging system) comprising an imaging device 250 including the camera module 300 of Figure 2 is mounted. As shown in the figure, the imaging device 250 can be mounted on the vehicle 240, and Figure 6 is an example of an arrangement illustrating the mounting position of the imaging device 250 on the vehicle 240. The imaging device 250 mounted on the vehicle 240 can also be called an in-vehicle camera and can be installed in various locations on the vehicle 240. For example, the first imaging device 250a may be placed on or near the front bumper as a camera to monitor the area in front of the vehicle 240 while it is in motion. The second imaging device 250b, which also monitors the area in front, may be placed near the rearview mirror inside the vehicle 240. The third imaging device 250c may be placed on the dashboard or inside the instrument panel, etc., as a camera to monitor the driver's driving conditions. The fourth imaging device 250d may be installed at the rear of the vehicle 240 for use as a rear monitor. Imaging devices 250a and 250b can be called front cameras. The third imaging device 250c can be called an in-camera. The fourth imaging device 250d can be called a rear camera. The imaging device 250 is not limited to these, and includes imaging devices installed in various positions, such as a left side camera that images the left rear side and a right side camera that images the right rear side.

[0034] The image signal of the image captured by the imaging device 250 can be output to an information processing device (control unit) 242 and / or a display device (output device) 243, etc., within the vehicle 240. These information processing devices 242 and 243 together with the imaging device 250 constitute an in-vehicle system. The information processing device 242 within the vehicle 240 includes a device that processes the image signal (captured image) acquired by the imaging device 250, recognizes the image (recognizes objects in the captured image), and assists the driver in driving. The information processing device 242 is also configured to output recognition information of objects in the captured image to the display device 243, and includes, but is not limited to, a navigation device, a collision damage mitigation braking device, a vehicle-to-vehicle distance control device, and a lane departure warning device. The display device 243 displays the image processed and output by the information processing device 242, but can also receive the image signal directly from the imaging device 250. Furthermore, the display device 243 may employ, but is not limited to, a liquid crystal display (LCD), an organic electro-luminescence (EL) display, or an inorganic EL display. The display device 243 can display image signals output from an imaging device 250, such as a rear camera, which captures images from positions that are difficult for the driver to see (it can output information to the occupants).

[0035] Figure 7 shows the configuration of the imaging device that constitutes the in-vehicle system shown in Figure 6. As shown in the figure, the imaging device 250 according to one embodiment comprises a control unit 252, a storage unit 254, and the camera module 300 shown in Figure 2.

[0036] The control unit 252 controls the camera module 300 and processes the electrical signals output from the image sensor (package sensor) 304 of the camera module 300. This control unit 252 may be configured as a processor, for example. The control unit 252 may also include one or more processors. The processors may include general-purpose processors that load a specific program and execute a specific function, and dedicated processors specialized for specific processing. Dedicated processors may include application-specific integrated circuits (ICs). Application-specific integrated circuits are also called ASICs (Application Specific Integrated Circuits). The processors may also include programmable logic devices. Programmable logic devices are also called PLDs (Programmable Logic Devices). PLDs may include field-programmable gate arrays (FPGAs). The control unit 252 may be either a system-on-a-chip (SoC) or a system-in-a-package (SiP) in which one or more processors cooperate. Furthermore, the control unit 252 may have the same functions as the information processing device 242 described above. For example, it may process the captured image output from the image sensor 304 to recognize objects in the captured image.

[0037] The storage unit 254 stores various information or parameters related to the operation of the imaging device 250. The storage unit 254 may be composed of, for example, a semiconductor memory. The storage unit 254 may function as a work memory for the control unit 252. The storage unit 254 may store captured images. The storage unit 254 may store various parameters, etc., for the control unit 252 to perform detection processing based on the captured images. The storage unit 254 may be included in the control unit 252.

[0038] As mentioned above, the camera module 300 captures the subject image formed via the lens unit 20 with the image sensor 304 and outputs the captured image. The image captured by the camera module 300 is also called the captured image.

[0039] The image sensor 304 may be composed of, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor or a CCD (Charge Coupled Device). The image sensor 304 has an imaging surface in which multiple pixels are arranged. Each pixel outputs a signal that is specified by current or voltage according to the amount of incident light. The signal output by each pixel is also called imaging data.

[0040] The image data may be read out by the camera module 300 for all pixels and taken into the control unit 252 as an image. The image data read out for all pixels is also called the maximum image. The image data may be read out by the camera module 300 for some pixels and taken into the image. In other words, the image data may be read out from pixels within a predetermined acquisition range. The image data read out from pixels within a predetermined acquisition range may be taken into the image. The predetermined acquisition range may be set by the control unit 252. The camera module 300 may obtain the predetermined acquisition range from the control unit 252. The image sensor 304 may capture an image within a predetermined acquisition range from the subject image formed via the lens unit 20.

[0041] It should be noted that the present invention is not limited to the embodiments described above, and can be implemented in various ways without departing from the spirit of the invention. For example, in the present invention, the shapes of the lens, lens barrel, intermediate ring, aperture member, etc., are not limited to the shapes of the embodiments described above. Also, although the aperture member is provided on the first intermediate ring in the embodiments described above, it may be provided on other intermediate rings in addition to or instead of this. Furthermore, without departing from the spirit of the present invention, some or all of the embodiments described above may be combined, or some of the components of one of the embodiments described above may be omitted. [Explanation of Symbols]

[0042] 11 Lens Unit 12 Telescope Tubes 20 Intermediate ring 20a Inner surface 30 Restriction member 30b Outer surface 40 Adhesive application area 42 recess 50 steps 242 Information Processing Devices 243 Display device 250 Imaging device 252 Control Unit 300 Camera Modules 304 Package Sensor (Image Sensor) L lens group O optical axis S Internal storage space

Claims

1. A lens unit comprising a lens group in which multiple lenses are arranged along the optical axis of the lens, a lens barrel having an inner housing space for housing and holding the lens group, an aperture member for adjusting the amount of light transmitted through the lens group, and an intermediate ring interposed between the lenses constituting the lens group, A lens unit characterized in that the aperture member is incorporated into the intermediate ring and fixed in place by adhesive.

2. The lens unit according to claim 1, characterized in that the intermediate ring has a recess for incorporating and housing the aperture member.

3. The lens unit according to claim 2, characterized in that the aperture member is disposed so as to fit completely within the recess of the intermediate ring.

4. The lens unit according to claim 2, characterized in that the recess is defined inward by the inner surface of the intermediate ring which holds the outer surface of the aperture member and positions the aperture member coaxially with the optical axis.

5. The lens unit according to claim 4, characterized in that the intermediate ring has an adhesive application portion to which an adhesive for bonding the aperture member to the intermediate ring is applied.

6. The lens unit according to claim 5, characterized in that the adhesive application portion is formed as a concave notch on the inner circumferential surface of the intermediate ring, forming an adhesive reservoir that allows adhesive to be applied between the aperture member and the intermediate ring.

7. The lens unit according to claim 6, characterized in that a step is formed on the radially inner edge of the annular bottom surface of the recess.

8. A camera module comprising a lens unit according to any one of claims 1 to 7, and an image sensor that converts light collected through the lens unit into an electrical signal.

9. An in-vehicle system installed in a vehicle, The camera module according to claim 8, A control unit that processes the captured image output from the image sensor of the camera module and recognizes an object in the captured image, An in-vehicle system characterized by having [a certain feature].

10. A mobile body equipped with the in-vehicle system described in claim 9 and an output device that outputs information to the occupants, The mobile body is characterized in that the control unit is configured to output recognition information of the object to the output device.

Images