A camera module and imaging system

Abstract

This invention relates to the field of image acquisition equipment technology, and discloses a camera module and imaging system. The camera module includes: a lens, a lens mount, a circuit board, an image sensor, and multiple support components. The lens is fixed in the lens mount, and the image sensor is mounted on the circuit board, with the lens and image sensor positioned opposite each other along the optical axis. The support components include rigid members and elastic members. The elastic members elastically support the lens mount and the rigid members, and provide elastic force to the rigid members toward the circuit board. When the imaging surface of the lens coincides with the photosensitive surface of the image sensor, the elastic members of each support component utilize the elastic force on the rigid members to automatically adjust the rigid members to always be in contact with the circuit board, ensuring direct contact between the rigid members and the circuit board. There is no adhesive between the surface of the rigid members in contact with the circuit board and the circuit board, which reduces the likelihood of poor alignment between the lens imaging surface and the photosensitive surface of the image sensor.

Description

Technical Field

[0001] This invention relates to the field of image acquisition equipment technology, and in particular to a camera module and imaging system. Background Technology

[0002] As image sensor pixels continue to upgrade, the resolution of camera lenses is required to be increasingly higher. However, the resolution margin of the lens relative to the image sensor is decreasing, meaning the focal depth range of the camera module is shrinking. This necessitates higher precision during camera module assembly. Furthermore, non-consumer camera modules are primarily fixed-focus modules (non-autofocus). Temperature changes cause the lens's optimal imaging plane to shift, and these modules operate under harsh temperature conditions (e.g., automotive applications typically require -40°C to +85°C). Maintaining good performance across the entire temperature range demands even higher precision during camera module assembly. This requires not only ensuring performance at room temperature but also considering lens back focus drift under low and high temperature conditions, resulting in even smaller assembly margins during room temperature assembly.

[0003] Considering the above three points: 1) With the upgrade of image sensor pixels, the resolving margin of the lens relative to the image sensor decreases, resulting in a smaller focal depth range for the module; 2) For fixed-focus camera modules, the position of the lens's back focus (optimal imaging plane) varies under different temperature conditions, meaning that the camera module will experience focus drift when the temperature changes; 3) In fields with high image quality requirements, during camera module assembly, the position of the lens's imaging plane must be as close as possible to the image sensor's photosensitive position, with minimal deviation, requiring higher assembly precision. The fixing method between the lens and the image sensor circuit board is generally achieved through UV adhesive curing. However, UV adhesives have a certain degree of shrinkage, and currently, regardless of the type of adhesive used, it is impossible to completely avoid this shrinkage problem. Furthermore, after curing, the amount of adhesive shrinkage is uneven in different locations.

[0004] For cameras requiring high-precision assembly, after the lens and circuit board are aligned to their optimal relative positions, they are connected and fixed to the circuit board or base using adhesive. This ensures that the lens and circuit board remain in their optimal relative position, meaning the lens's imaging surface coincides with the photosensitive surface of the image sensor on the circuit board. However, adhesives have a characteristic of shrinking after curing, and the amount of shrinkage varies depending on the adhesive thickness; the thicker the adhesive, the greater the shrinkage. Furthermore, even with the same adhesive thickness, the amount of shrinkage differs due to variations in curing conditions (UV exposure curing, thermal curing); the greater the adhesive thickness, the greater the difference in shrinkage. Reduced alignment between the lens's imaging surface and the image sensor's photosensitive surface on the circuit board leads to optical axis misalignment between the lens and the image sensor.

[0005] Therefore, in camera modules that require high-precision assembly, the poor overlap between the lens imaging surface and the image sensor photosensitive surface caused by inconsistent adhesive thickness is a problem that needs to be addressed promptly. Summary of the Invention

[0006] This invention discloses a camera module and imaging system to alleviate the problem of poor overlap between the lens imaging surface and the image sensor photosensitive surface caused by inconsistent adhesive thickness.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, a camera module is provided, comprising: a lens, a lens mount, a circuit board, an image sensor, and multiple support components; the lens is fixed in the lens mount, the image sensor is disposed on the circuit board, and the lens and the image sensor are disposed opposite each other along the optical axis; the support components include a rigid member and an elastic member, the elastic member being elastically supported between the lens mount and the rigid member, and used to provide an elastic force towards the circuit board to the rigid member. When the imaging surface of the lens coincides with the photosensitive surface of the image sensor, the elastic member of each support component uses its elastic force on the rigid member to automatically adjust the rigid member to always abut against the circuit board, ensuring direct contact between the rigid member and the circuit board, a zero-gap rigid connection, and no adhesive between the surface of the rigid member in contact with the circuit board and the circuit board, thus reducing the likelihood of poor alignment between the lens imaging surface and the photosensitive surface of the image sensor due to adhesive shrinkage. Furthermore, even if there is adhesive between the rigid component and the non-contact area of ​​the circuit board, the tension exerted on the rigid component along the optical axis by the adhesive shrinking will be automatically offset by the elastic force of the elastic component, allowing the rigid component to automatically adapt to the tension caused by adhesive shrinkage. In addition, the position of the rigid component in each support assembly is individually customized based on its location. Once connected, the position of the rigid component is largely unaffected by other factors, resulting in high stability and mitigating the problem of poor alignment between the lens imaging surface and the image sensor photosensitive surface caused by inconsistent adhesive thickness.

[0009] Optionally, the support assembly further includes a mounting sleeve fixedly connected to the lens mount, the mounting sleeve having a slide rail with an opening facing the circuit board, the rigid member slidingly adapted to the slide rail along the optical axis direction; the elastic member elastically supported between the bottom surface of the slide rail and the rigid member.

[0010] Optionally, the support assembly further includes a preload member for adjusting the preload force of the elastic member.

[0011] Optionally, the preload is threaded to the mounting sleeve along the optical axis and connected to the end of the elastic member away from the rigid member.

[0012] Optionally, the preload includes a slider and a fastener, the outer diameter of the slider being larger than the outer diameter of the preload; the slider is slidably fitted in the slide rail and connected to the end of the elastic member away from the rigid member; the fastener is threadedly connected to the end of the mounting sleeve away from the circuit board and abuts against the slider.

[0013] Optionally, both the mounting sleeve and the rigid member are cylindrical structures and are coaxially arranged along the optical axis, with the mounting sleeve embedded in the lens mount.

[0014] Optionally, the outer diameter of the rigid member gradually decreases at the end closest to the circuit board.

[0015] Optionally, the rigid member has a spherical surface at one end near the circuit board.

[0016] Optionally, a plurality of the support components are spaced apart and evenly distributed around the lens.

[0017] Optionally, the support assembly further includes a locking member for locking the rigid member to the lens mount.

[0018] Optionally, the locking element includes a screw that is threadedly connected to the lens mount and abuts against the circumferential surface of the rigid member.

[0019] Secondly, an imaging system is provided, comprising: the camera module described in any of the above technical solutions.

[0020] The imaging system described above has the same advantages over existing technologies as the camera module mentioned above, and will not be repeated here. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the camera module provided in the embodiments of this application;

[0022] Figure 2 express Figure 1 A perspective view of the camera module shown;

[0023] Figure 3 express Figure 1 Sectional view along the AA direction. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] During the manufacturing process of the camera module, deviations exist in various components, primarily in the lens (such as optical back focal length deviation and optical axis tilt deviation). The optical lens comprises several lens elements and structural components (such as spacers and lens barrels). Theoretically, tolerances are unavoidable for all lens elements and structural components, leading to inconsistencies in the position of the optical focal plane relative to the adhesive bonding surface. This directly results in inconsistent adhesive thickness. Furthermore, deviations in image sensor height and base height directly affect the size of the mating clearance, thus influencing the adhesive thickness.

[0026] In camera modules that require high-precision assembly, inconsistent adhesive thickness can easily lead to poor alignment between the lens imaging surface and the image sensor photosensitive surface, resulting in optical axis deviation between the lens and the image sensor.

[0027] refer to Figures 1 to 3 :

[0028] This application also provides a camera module to alleviate the above-mentioned problems. This application does not merely reduce the thickness of the adhesive to decrease shrinkage differences, but directly utilizes the rigidity of the rigid member 11 to allow the lens 4 to directly contact the circuit board 2, fundamentally changing the connection method between the two and avoiding inherent defects of the adhesive and the structure.

[0029] The camera module includes: a lens 4, a lens mount 3, a circuit board 2, an image sensor 6, a base 7, and multiple support components 1; the lens 4 is fixed in the lens mount 3, the image sensor 6 is disposed on the circuit board 2, the circuit board 2 can be mounted on the base 7, and the lens 4 and the image sensor 6 are arranged opposite each other along the optical axis L so that the imaging surface of the lens 4 coincides with the photosensitive surface of the image sensor 6; the support components 1 include a rigid member 11 and an elastic member 12, the elastic member 12 is elastically supported between the lens mount 3 and the rigid member 11, and is used to provide the rigid member 11 with an elastic force toward the circuit board 2. When the imaging surface of lens 4 coincides with the photosensitive surface of image sensor 6, the elastic element 12 of each support component 1 uses its elastic force on the rigid component 11 to automatically adjust the rigid component 11 to abut against the circuit board 2, ensuring direct contact and zero-gap rigid connection between the rigid component 11 and the circuit board 2. There is no adhesive between the surface of the rigid component 11 and the circuit board 2, which reduces the likelihood of poor alignment between the imaging surface of lens 4 and the photosensitive surface of image sensor 6 due to adhesive shrinkage. Furthermore, even if there is adhesive between the non-contact area of ​​the rigid component 11 and the circuit board 2, the tension on the rigid component 11 in the optical axis L direction when the adhesive shrinks will be automatically offset by the elastic force of the elastic element 12 on the rigid component 11, allowing the rigid component 11 to automatically adapt to the tension caused by adhesive shrinkage. In each support component 1, the position of the rigid member 11 is individually customized based on its location. After connection, the position of the rigid member 11 is largely unaffected by other factors, resulting in high stability. This helps alleviate the problem of poor alignment between the imaging surface of the lens 4 and the photosensitive surface of the image sensor 6 caused by inconsistent adhesive thickness. The circuit board 2 can specifically be a printed circuit board. The elastic element 12 can be a compression spring arranged along the optical axis L, or other elastic structural components. The rigid member 11 can be made of high-rigidity steel, which is corrosion-resistant, less affected by temperature and humidity, and has high strength and rigidity.

[0030] In one specific embodiment, the support assembly 1 further includes a mounting sleeve 15 fixedly connected to the lens mount 3. The mounting sleeve 15 has a slide rail V with an opening facing the circuit board 2. The rigid member 11 is slidably adapted to the slide rail V along the optical axis L. An elastic member 12 is elastically supported between the bottom surface of the slide rail V and the rigid member 11. The mounting sleeve 15 serves as the mounting base for the rigid member 11 and the elastic member 12, making the support assembly 1 a whole. During installation, the mounting sleeve 15 only needs to be embedded into the lens mount 3. Specifically, an inlay groove T extending along the optical axis L can be provided in the lens mount 3, and it can be installed by an interference fit. Furthermore, the slide rail V of the mounting sleeve 15 plays a limiting and guiding role for the elastic member 12 and the rigid member 11, preventing them from deviating laterally from the track during movement.

[0031] In one specific embodiment, the support assembly 1 further includes a pre-tightening member 13, which is used to adjust the pre-tightening force of the elastic member 12. Because the structural dimensional tolerances of the lens mount 3 and the circuit board 2 differ at different locations, the adhesive distribution thickness also varies, and the tension on the rigid member 11 in the optical axis L direction when the adhesive shrinks is also different. Therefore, the required elastic force of the elastic member 12 in each support assembly 1 is different. By adjusting the pre-tightening force of the elastic member 12, the required elastic force of different support assemblies 1 can be accommodated.

[0032] In one specific embodiment, the preload 13 is threadedly connected to the mounting sleeve 15 along the optical axis L and connected to the end of the elastic member 12 away from the rigid member 11. By rotating the preload 13, the position of that end of the elastic member 12 can be moved along the optical axis L. The end of the elastic member 12 close to the rigid member 11 is connected to the rigid member 11. Therefore, the length of the elastic member 12 can be adjusted to achieve different sizes of preload force.

[0033] In one specific embodiment, the preload 13 includes a slider 132 and a fastener 131. The fastener 131 can specifically be a graduated feed screw. The outer diameter of the slider 132 is larger than the outer diameter of the preload 13. The slider 132 is slidably fitted in the slide rail V and connected to the end of the elastic member 12 away from the rigid member 11. The fastener 131 is threadedly connected to the end of the mounting sleeve 15 away from the circuit board 2 and abuts against the slider 132. The fastener 131 has a smaller outer diameter, avoiding the need for a large threaded hole in the mounting sleeve 15, which is beneficial to improving the structural stability of the mounting sleeve 15. The slider 132 with a larger outer diameter can be adapted to the slide rail V with the same inner diameter, and can cover the corresponding end of the elastic member 12, thus preventing the fastener 131 from being inserted into the hollow position of the elastic member 12 (compression spring).

[0034] In one specific embodiment, both the mounting sleeve 15 and the rigid member 11 are cylindrical structures and are coaxially arranged along the optical axis L. The mounting sleeve 15 is embedded in the lens mount 3, specifically, it can be an interference fit in the corresponding mounting groove of the lens mount 3. The depth of the mounting groove can be greater than the embedding depth of the mounting sleeve 15 to facilitate the installation of the pre-tightening member 13. Compared with the rigid member 11 of sheet-like or other shapes, the cylindrical rigid member 11 is equivalent to a support leg, reducing the contact area with the circuit board 2. Compared with a larger contact area, it can reduce the difficulty of contact matching, making the rigid member 11 and the circuit board 2 close to point-to-surface contact, which facilitates the formation of direct rigid contact.

[0035] In one specific embodiment, the mounting sleeve 15 has a sliding groove U in the direction of the optical axis L, and a sliding protrusion 14 is provided on the circumferential surface of the rigid member 11. The sliding protrusion 14 is slidably engaged in the sliding groove U along the direction of the optical axis L to prevent the rigid member 11 from rotating around its own axis, thereby improving the stability of the contact between the rigid member 11 and the circuit board 2 and ensuring the bonding effect. Furthermore, the sliding protrusion 14 can contact the inner wall of the sliding groove U in the lateral direction to further reduce the possibility of the rigid member 11 rotating.

[0036] In one specific embodiment, the outer diameter of the rigid member 11 gradually decreases at the end closest to the circuit board 2 to further reduce the contact area between the rigid member 11 and the circuit board 2, making it closer to point-to-surface contact. Furthermore, when the portion with the gradually decreasing outer diameter is symmetrical about the axis of the rigid member 11, the contact point between the rigid member 11 and the circuit board 2 is located on the axis of the rigid member 11. When adhesive is filled between the non-contact area at this end and the circuit board 2, the lateral tensile force generated by the shrinkage of the adhesive on the rigid member 11 cancels each other out, and the tensile force in the optical axis L direction can be automatically compensated by the elastic member 12.

[0037] In one specific embodiment, the rigid member 11 has a spherical surface at one end near the circuit board 2. The spherical surface can reduce the probability of scratching the circuit board 2 and can concentrate the contact surface between the rigid member 11 and the circuit board 2 at the bottommost point, which facilitates rigid contact with the circuit board 2.

[0038] In one specific embodiment, multiple support components 1 are spaced apart and evenly distributed around the lens 4 to provide uniform support for the lens mount 3 in all directions. Otherwise, the lens mount 3 is prone to tilting, causing assembly tolerances and resulting in a deviation of the optical axis L between the image sensor 6 and the lens 4. Figure 2 In this case, the number of support components 1 can be 4, with each of the 4 support components being set one-to-one at one of the 4 corners of the square lens mount 3.

[0039] In one specific embodiment, the support component 1 further includes a locking member 5, which is used to lock the rigid member 11 to the lens mount 3. After the photosensitive surface of the image sensor 6 and the imaging surface of the lens 4 are adjusted to coincide, the positions of each rigid member 11 are locked, which can prevent the rigid member 11 from being squeezed and displaced later, so that the originally coincident photosensitive surface and imaging surface do not coincide again.

[0040] In one specific embodiment, the locking member 5 includes a screw, which is threadedly connected to the lens mount 3 and abuts against the circumferential surface of the rigid member 11. The rigid member 11 is locked using the frictional force of the screw against it, making the operation convenient and the structure simple.

[0041] In another specific embodiment, adhesives such as glue can be used to bond and fix the rigid member 11 to the lens mount 3. However, in order to avoid the problem of optical axis L deviation caused by adhesive shrinkage due to adhesive flowing to the bottom of the rigid member 11, a rubber ring can be fitted on the rigid member 11 to prevent the adhesive from flowing down.

[0042] The above represents a revolutionary change to the commonly used, traditional, and simple adhesive connection method. It increases the rigidity between the two components, resulting in a more stable connection with better retention and less susceptibility to external influences. This connection method completely eliminates the effects of adhesive shrinkage, making it a high-quality connection less susceptible to operational precision issues. In this method, the rigid component 11 serves as the main connection element, while the adhesive only secures the rigid component 11 to the circuit board 2.

[0043] When the camera module is used within the normal temperature range, the effect of temperature on the connection between lens 4 and circuit board 2 is negligible. The rigid component 11 used for the connection exhibits virtually no deformation when used at room temperature.

[0044] The following explains how to achieve a rigid connection between lens 4 and circuit board 2.

[0045] Four sets of support components 1 are embedded around the lens mount 3, arranged as evenly as possible, so that the reaction force of the elastic element 12 is evenly transmitted to the circuit board 2. The clamping area on the circuit board 2 corresponding to the lens mount 3 is copper-plated, which cooperates with the support components 1 to facilitate sliding and precise fit. There is sufficient support under the clamping area corresponding to the image sensor 6 clamping mechanism, and the clamping mechanism has good rigidity. In addition to the clamping claws, the clamping mechanism of the lens 4 is also designed with a bearing surface clamping device to make the clamping of the lens 4 sufficiently stable, with good rigidity and strength. The relative positions of the high-definition camera and the support components 1 are reasonably arranged so that the high-definition camera can observe the gap between the lens 4 and the image sensor 6, and can also calculate the angle and position based on the position of the set screw. The locking component 5 is equipped with thread adhesive and has an initial position mark. The locking component 5 should not be tightened initially to prevent the locking component 5 from locking up, which would prevent the support components 1 from moving smoothly and make it impossible to adjust successfully. A tightening motor system is provided to tighten the locking component 5 to cover the area of ​​the locking component 5 corresponding to the support components 1 on both sides. The fixed motor system features force feedback, and the head has a micro-motion tensioning and contraction function. Additionally, the head's rotation angle is recorded. The support component 1 has good precision, with the gap between the mounting sleeve 15 and the rigid component 11 ranging from +0.01 to +0.02 mm. After assembly, it moves smoothly without jamming. The elasticity of the elastic element 12 is moderate. The tension of the elastic element 12 is determined based on factors such as the shrinkage force of the adhesive, the amount of adhesive, the contact area between the adhesive and the lens mount 3, the material and surface treatment method of the lens mount 3, the cleanliness of the lens mount 3, and its surface energy. The adhesive application area on the circuit board 2 is the copper-clad area of ​​the circuit board 2, used to secure the rigid component 11 to the circuit board 2, thereby achieving a rigid connection between the lens mount 3 and the circuit board 2.

[0046] In addition, the equipment used to manufacture camera modules is also equipped with the following components:

[0047] The XYZ three-axis motion platform is used to move the lens 2 and the image sensor 6 to a designated position.

[0048] The six-axis displacement stage can be adjusted in six directions to achieve the relative position of lens 4 and image sensor 6.

[0049] Test card, a standard card used to view images.

[0050] Circuit board clamping assembly, used to place and clamp circuit board 2.

[0051] A relay lens system is used to simulate object distances at different distances for lens 4.

[0052] A lens clamping assembly is used to clamp and secure the lens 4.

[0053] The process for manufacturing the camera module is as follows:

[0054] After aligning the imaging surface of lens 4 with the photosensitive surface of image sensor 6, four high-definition cameras simultaneously take pictures, calculate the angle and position of locking component 5, and measure the gap and position between lens 4 and circuit board 2.

[0055] The system analyzes and calculates the results obtained from the high-definition camera to determine the position and rotation angle of the corresponding locking component 5. It then issues corresponding instructions to adjust the locking motor system so that the locking motor head rotates to the corresponding angle and controls the locking motor system to move along the X, Y, and Z axes to the corresponding position.

[0056] The locking motor system performs the tightening action of the locking member 5. The force sensor monitors the tightening status of the locking member 5 in real time. When the force sensor reaches the corresponding predetermined value, the tightening stops and the locking member 5 rotates in the opposite direction by a certain angle, so that the locking motor system can be smoothly disengaged.

[0057] While the locking component 5 is being tightened, the high-definition camera is also simultaneously monitoring the gap and relative position between the lens mount 3 and the circuit board 2 in real time to ensure that the gap and relative position between the lens mount 3 and the circuit board 2 remain unchanged.

[0058] Once all the above actions are completed, turn on the UV probe to cure the rigid component 11 and the circuit board 2.

[0059] Meanwhile, the high-definition camera continues to monitor the gap and position between the lens 4 and the circuit board 2 in real time, ensuring that the gap and relative position between the lens 4 and the circuit board 2 remain unchanged.

[0060] Once the curing process is complete, remove the camera module.

[0061] Based on the same inventive concept, this application also provides an imaging system, which includes the camera module provided in the above embodiments. The beneficial effects of the camera module can be referred to the relevant description of the camera module above.

[0062] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A camera module, characterized in that, include: Lens, lens mount, circuit board, image sensor, and multiple support components; The lens is fixed in the lens mount, the image sensor is disposed on the circuit board, and the lens and the image sensor are arranged opposite to each other along the optical axis. The support assembly includes a rigid member and an elastic member. The elastic member is elastically supported between the lens mount and the rigid member and is used to provide an elastic force to the rigid member toward the circuit board so that the rigid member abuts against the circuit board. The support assembly further includes a mounting sleeve fixedly connected to the lens mount, the mounting sleeve having a slide rail with an opening facing the circuit board, and the rigid member slidingly adapted to the slide rail along the optical axis. The elastic element is elastically supported between the bottom surface of the slide and the rigid component; The support assembly further includes a preload member, which is used to adjust the preload force of the elastic member; The preload is threaded to the mounting sleeve along the optical axis and is connected to the end of the elastic member away from the rigid member.

2. The camera module according to claim 1, characterized in that, The preload component includes a slider and a fastener, wherein the outer diameter of the slider is larger than the outer diameter of the preload component; The slider is slidably fitted in the slide rail and connected to the end of the elastic member away from the rigid member; The fastener is threaded onto the end of the mounting sleeve furthest from the circuit board and abuts against the slider.

3. The camera module according to claim 1, characterized in that, Both the mounting sleeve and the rigid component are cylindrical structures and are coaxially arranged along the optical axis. The mounting sleeve is embedded in the lens mount.

4. The camera module according to claim 3, characterized in that, The outer diameter of the rigid member gradually decreases at the end closest to the circuit board.

5. The camera module according to claim 4, characterized in that, The rigid member has a spherical surface at one end near the circuit board.

6. The camera module according to claim 3, characterized in that, The multiple support components are spaced apart and evenly distributed around the lens.

7. The camera module according to claim 3, characterized in that, The support assembly also includes a locking element for locking the rigid member to the lens mount.

8. The camera module according to claim 7, characterized in that, The locking element includes a screw that is threadedly connected to the lens mount and abuts against the circumferential surface of the rigid member.

9. An imaging system, characterized in that, include: The camera module according to any one of claims 1 to 8.

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