MEMS multi-dimensional pose adjustable optical imaging device and system

Abstract

The invention discloses an MEMS multi-dimensional pose adjustable optical imaging device and system, and relates to the technical field of micro electro mechanical systems and optical imaging, the MEMS multi-dimensional pose adjustable optical imaging device comprises an MEMS multi-degree-of-freedom micro chip, an image sensor and an adapter plate, the image sensor is packaged on the adapter plate to form an image sensor assembly, and the adapter plate is connected with the MEMS multi-degree-of-freedom micro chip. The micro-motion module is carried on the MEMS multi-degree-of-freedom micro The MEMS multi-degree-of-freedom micro-motion chip comprises a chip substrate, a micro-motion platform and a driving assembly connecting the chip substrate and the micro-motion platform. The driving assembly comprises a plurality of driving arms and a plurality of flexible leads; and the image sensor assembly outputs image information through a flexible lead and performs multi-degree-of-freedom movement through the driving arm. According to the invention, packaging integration of the MEMS chip and the image sensor can be realized, and multi-degree-of-freedom motion of the image sensor is driven through the MEMS chip.

Description

Technical Field

[0001] This application relates to the fields of microelectromechanical systems and optical imaging technology, and in particular to a MEMS multi-dimensional pose-adjustable optical imaging device and system. Background Technology

[0002] Traditional image sensors rely primarily on electric motors or voice coil motors for focal plane modulation, which suffers from slow response speed and limited focusing accuracy, making it difficult to meet the demands of high dynamic scenes. Electric motors have issues such as large transmission structure size, limited response speed due to transmission inertia, and low focusing accuracy; voice coil motors have structures such as coils and bearings, making miniaturization difficult, and their accuracy is affected by factors such as mechanical hysteresis.

[0003] MEMS (Micro-Electro-Mechanical System) multi-dimensional pose-tunable optical imaging devices are drivers that integrate microcircuits and micromechanics on a chip according to functional requirements. Their size is typically in the millimeter or micrometer range, and they can solve many problems associated with focal plane modulation in image sensors. In existing technologies, some MEMS multi-dimensional pose-tunable optical imaging devices are small in size, but when applied to focal plane modulation systems, the communication signal quality is poor, affecting image quality. Other MEMS multi-dimensional pose-tunable optical imaging devices can maintain communication quality, but their complex structure and large size result in excessively large focal plane modulation systems, making them difficult to meet practical application requirements. Summary of the Invention

[0004] The purpose of this application is to provide a MEMS multi-dimensional pose-adjustable optical imaging device and system, which can realize multi-degree-of-freedom motion of the image sensor while effectively avoiding the influence of parasitic capacitance caused by the drive arm and signal transmission line on image information transmission, thereby improving image transmission quality.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, a MEMS multi-dimensional pose-adjustable optical imaging device is provided, characterized in that the MEMS multi-dimensional pose-adjustable optical imaging device includes a MEMS multi-degree-of-freedom micro-motion chip, an image sensor and an adapter board, wherein the image sensor is packaged in the adapter board to form an image sensor assembly, and the image sensor assembly is mounted on the MEMS multi-degree-of-freedom micro-motion chip.

[0006] The MEMS multi-degree-of-freedom micro-motion chip includes a chip substrate, a micro-motion platform, and a driving component for connecting the chip substrate and the micro-motion platform; the driving component includes several driving arms and several flexible leads; the image sensor component outputs image information through the flexible leads and performs multi-degree-of-freedom motion through the driving arms.

[0007] The micro-motion platform is supported and suspended by the drive assembly, and several drive arms and several flexible leads in the drive assembly are arranged around the micro-motion platform.

[0008] The drive arm includes an anchoring structure, a deformation structure, and a connecting structure; one end of the deformation structure is fixedly connected to the chip substrate through the anchoring structure, and the other end of the deformation structure is connected to the micro-motion platform through the connecting structure.

[0009] Secondly, this application provides an imaging system based on a MEMS multi-dimensional pose-adjustable optical imaging device, including an optical lens group and the aforementioned MEMS multi-dimensional pose-adjustable optical imaging device.

[0010] The MEMS multi-dimensional pose-adjustable optical imaging device is fixedly connected to the optical lens group, and the image sensor assembly is coaxial with the center of the optical lens group.

[0011] The optical lens assembly is used to transmit external light to the image sensor assembly.

[0012] Thirdly, this application provides a focusing system for a MEMS multi-dimensional pose-adjustable optical imaging device, including a processor and the aforementioned MEMS multi-dimensional pose-adjustable optical imaging device.

[0013] The processor is used to acquire image information output by the flexible lead wire and process the image information to obtain focusing parameters; the focusing parameters are used to control the drive arm to move along the focusing direction so that the image sensor assembly can perform multi-dimensional motion.

[0014] According to the specific embodiments provided in this application, this application has the following technical effects: This application provides a MEMS multi-dimensional pose-adjustable optical imaging device and system. The MEMS multi-dimensional pose-adjustable optical imaging device includes a MEMS multi-degree-of-freedom micro-motion chip, an image sensor, and an adapter plate. The image sensor is packaged in the adapter plate to form an image sensor assembly, which is mounted on the MEMS multi-degree-of-freedom micro-motion chip. The MEMS multi-degree-of-freedom micro-motion chip includes a chip substrate, a micro-motion platform, and a driving component for connecting the chip substrate and the micro-motion platform, arranged sequentially from the outside to the inside. The driving component includes several driving arms and several flexible leads. The image sensor assembly outputs image information through the flexible leads and performs multi-degree-of-freedom motion through the driving arms. The micro-motion platform is supported and suspended by the driving component. Several driving arms and several flexible leads in the driving component are arranged around the micro-motion platform. The driving arm includes an anchoring structure, a deformation structure, and a connecting structure. One end of the deformation structure is fixedly connected to the chip substrate through the anchoring structure, and the other end of the deformation structure is connected to the micro-motion platform through the connecting structure. By setting the drive arm and flexible leads independently, and using the flexible leads as signal lines, the impact of parasitic capacitance caused by the drive arm and signal transmission lines on image information transmission can be effectively avoided, thus improving image transmission quality. At the same time, the flexible leads solve the problems of large size, low integration, and difficult manufacturing process caused by connecting the image sensor to the chip substrate by wire bonding. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a MEMS multi-dimensional pose-adjustable optical imaging device according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a drive arm in a MEMS multi-dimensional pose-adjustable optical imaging device according to an embodiment of this application; Figure 3 This is a schematic diagram of another drive arm in a MEMS multi-dimensional pose-adjustable optical imaging device according to one embodiment of this application; Figure 4 This is a schematic diagram of the distribution of the drive arm and flexible lead wire of a MEMS multi-dimensional pose-adjustable optical imaging device in one embodiment of this application. Figure 5 This is a schematic diagram of a connection structure between an image sensor and an adapter board in one embodiment of this application; Figure 6 This is a schematic diagram of another connection structure between the image sensor and the adapter board in one embodiment of this application; Figure 7 This is a schematic diagram of the structure of a MEMS multi-dimensional pose-adjustable optical imaging device according to another embodiment of this application; Figure 8 This is a schematic diagram of the capacitor plate structure of a capacitive position detection method according to an embodiment of this application.

[0017] Reference numerals: 1. Bottom circuit board; 2. MEMS multi-degree-of-freedom micro-motion chip; 21. Chip substrate; 22. Micro-motion platform; 23. Driving assembly; 24. U-shaped gap; 25. Driving arm; 251. Anchoring structure; 252. Deformation structure; 2521. L-shaped straight arm; 2522. Deformation part; 253. Connecting structure; 26. Flexible lead wire; 27. Image sensor assembly; 271. Image sensor; 272. Adapter board. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] Explanation of technical terms: MEMS: Micro-Electro-Mechanical System, is a structure that integrates microcircuits and micromechanical components onto a chip according to functional requirements, typically in the millimeter or micrometer range. Multi-dimensional pose-adjustable optical imaging devices within MEMS are the driving structures of MEMS used to achieve multi-dimensional pose adjustment.

[0021] Focal plane modulation: also known as focusing or focusing, adjusts the relative distance between the image sensor's imaging plane and the optical lens to ensure that the subject is clearly focused on the imaging plane.

[0022] Optical image stabilization: External shaking can cause image blurring in an imaging system. By controlling internal optical components, this blurring is compensated for. Based on the controlled components, it can be divided into sensor-based image stabilization and lens-based image stabilization. In contrast, image stabilization uses algorithms to compensate for image damage; this is called electronic image stabilization.

[0023] Tilt-shift photography: While keeping the camera body and film plane in the same position, the principal optical axis of the entire lens is shifted, tilted, or rotated to adjust the perspective of the photographed image or to achieve full-area focus.

[0024] Bimorph: A bimorph is a composite structure composed of two layers of materials. In an electrothermal bimorph, the two materials have different coefficients of thermal expansion, allowing them to bend and deform through electrical heating.

[0025] In one exemplary embodiment, such as Figure 1 As shown, a MEMS multi-dimensional pose-adjustable optical imaging device is provided. The MEMS multi-dimensional pose-adjustable optical imaging device includes a MEMS multi-degree-of-freedom micro-motion chip 2, an image sensor 271, and an adapter plate 272. The image sensor 271 is packaged in the adapter plate 272 to form an image sensor assembly 27, and the image sensor assembly 27 is mounted on the MEMS multi-degree-of-freedom micro-motion chip 2.

[0026] The MEMS multi-degree-of-freedom micro-motion chip 2 includes a chip substrate 21 and a micro-motion platform 22 arranged sequentially from the outside to the inside, and a driving component 23 for connecting the chip substrate 21 and the micro-motion platform 22; the driving component 23 includes a plurality of driving arms 25 and a plurality of flexible leads 26; the image sensor component 27 outputs image information through the flexible leads 26 and performs multi-degree-of-freedom motion through the driving arms 25.

[0027] The micro-motion platform 22 is supported and suspended by the drive assembly 23, and a plurality of drive arms 25 and a plurality of flexible leads 26 in the drive assembly 23 are arranged around the micro-motion platform.

[0028] Among them, such as Figure 2 and Figure 3 As shown, the drive arm includes an anchoring structure 251, a deformation structure 252, and a connecting structure 253; one end of the deformation structure 252 is fixedly connected to the chip substrate through the anchoring structure 251, and the other end of the deformation structure 252 is connected to the micro-motion platform through the connecting structure 253.

[0029] In one exemplary embodiment, such as Figure 7 As shown, a MEMS multi-dimensional pose-adjustable optical imaging device is provided, which also includes a bottom circuit board 1, and the MEMS multi-degree-of-freedom micro-motion chip 2 is disposed on the bottom circuit board 1.

[0030] like Figure 1As shown, the MEMS multi-degree-of-freedom micro-motion chip 2 includes a chip substrate 21, a micro-motion platform 22 and a driving component 23 for connecting the chip substrate 21 and the micro-motion platform 22, arranged sequentially from the outside to the inside; there is a U-shaped gap 24 between the chip substrate 21 and the micro-motion platform 22; the driving component 23 includes a plurality of driving arms 25 and a plurality of flexible leads 26.

[0031] The image sensor component 27 being mounted on the MEMS multi-degree-of-freedom micro-motion chip 2 means that the image sensor component 27 is mounted on the micro-motion platform 21.

[0032] In one exemplary embodiment, the loop gap 24 includes four channels, each of which is provided with a plurality of drive arms 25 and / or a plurality of flexible leads 26.

[0033] In one exemplary embodiment, such as Figure 1 As shown, the loop gap 24 includes four channels, namely a first channel, a second channel, a third channel, and a fourth channel connected in sequence; the plurality of drive arms 25 include a plurality of first drive arms and a plurality of second drive arms; the plurality of flexible leads 26 include a plurality of first flexible leads and a plurality of second flexible leads; the first drive arms are disposed in the first channel, the second drive arms are disposed in the third channel, the first flexible leads are disposed in the second channel, and the second flexible leads are disposed in the fourth channel. In another exemplary embodiment, as... Figure 4 As shown, the loop gap includes four channels, and a plurality of the drive arms 25 and a plurality of the flexible leads 26 are spaced apart in the four channels of the loop gap.

[0034] In one exemplary embodiment, such as Figure 2 As shown, the drive arm includes an anchoring structure 251, a deformation structure 252, and a connecting structure 253; one end of the deformation structure 252 is fixedly connected to the chip substrate 21 through the anchoring structure 251, and the other end of the deformation structure 252 is connected to the micro-motion platform 22 through the connecting structure 253.

[0035] In one exemplary embodiment, the method is the same as the previous embodiment, except that the deformable structure 252 includes m L-shaped straight arms 2521 and m+1 deformable parts 2522, where m≥2; Figure 2 As shown, the drive arm corresponding to the deformation structure with m=2 is illustrated.

[0036] The L-shaped straight arm 2521 includes a first rigid beam, a second rigid beam, and a right-angle transition zone connecting the first rigid beam and the second rigid beam; the extension direction of the first rigid beam and the extension direction of the second rigid beam are orthogonal to each other.

[0037] One end of the first rigid beam of the first L-shaped straight arm 2521 is connected to the anchoring structure 251 through the first deformation part 2522. The other end of the first rigid beam of the first L-shaped straight arm 2521 is connected to the other end of the second rigid beam of the first L-shaped straight arm 2521 through the right-angle transition area of ​​the first L-shaped straight arm 2521. One end of the second rigid beam of the first L-shaped straight arm 2521 is connected to one end of the first rigid beam of the second L-shaped straight arm 2521 through the second deformation part 2522.

[0038] In some embodiments, when m≥3, one end of the first rigid beam of the nth L-shaped straight arm is connected to one end of the second rigid beam of the (n-1)th L-shaped straight arm through the nth deformation part 2522, the other end of the first rigid beam of the nth L-shaped straight arm 2521 is connected to the other end of the second rigid beam of the nth L-shaped straight arm 2521 through the right-angle transition area of ​​the nth L-shaped straight arm 2521, and one end of the second rigid beam of the nth L-shaped straight arm is connected to one end of the second rigid beam of the (n+1)th L-shaped straight arm through the (n+1)th deformation part 2522, where 1<n<m.

[0039] One end of the first rigid beam of the m-th L-shaped straight arm 2521 is connected to one end of the second rigid beam of the (m-1)-th L-shaped straight arm 2521 through the m-th deformation part 2522. The other end of the first rigid beam of the m-th L-shaped straight arm 2521 is connected to the other end of the second rigid beam of the m-th L-shaped straight arm 2521 through the right-angle transition area of ​​the m-th L-shaped straight arm 2521. One end of the second rigid beam of the m-th L-shaped straight arm 2521 is connected to the connecting structure 253 through the (m+1)-th deformation part 2522.

[0040] The anchoring structure 251, the connecting structure 253, and the L-shaped straight arm 2521 are all made of conductive material.

[0041] In one exemplary embodiment, such as Figure 2 As shown, the same as the previous embodiment, except that the deformable part 2522 is a bicrystalline wafer, which is a stacked structure formed by an Al sheet and a photosensitive polyimide sheet.

[0042] Figure 2 The device includes two symmetrically placed drive arms. In one optional implementation, each deformation portion 2522 in the two symmetrically placed drive arms has the same length, and each deformation portion 2522 integrates a resistance heating layer for generating Joule heating. When a voltage or current excitation is applied, the two thin sheets of material with different coefficients of thermal expansion of the bicrystalline wafer undergo synchronous thermal bending deformation, thereby achieving vertical translation of the image sensor assembly.

[0043] In practical applications, multiple pairs of symmetrical drive arms can be configured, or only multiple single drive arms can be used. Preferably, multiple drive arms are typically used to provide sufficient driving capacity to achieve a larger displacement.

[0044] As an optional implementation, the drive arm adopts an LSF (Lateral Shift Free) electrothermal drive structure, which is mainly composed of two alternating parts: Bimorph and straight arm. The Bimorph mainly plays the role of deformation displacement, while the straight arm plays the role of amplifying displacement.

[0045] In one exemplary embodiment, the flexible lead includes at least one layer of conductive material, which is a metal or polycrystalline silicon.

[0046] In one exemplary embodiment, the flexible lead is folded.

[0047] In one exemplary embodiment, the image sensor is a CMOS image sensor or a CCD image sensor.

[0048] In one exemplary embodiment, the adapter board has a plurality of electrical connection points for electrically connecting to the image sensor.

[0049] In one exemplary embodiment, the adapter board has a plurality of passive devices and electrical connections, which are used to configure the image sensor to achieve imaging functionality.

[0050] In the prior art, in order to reduce the size of MEMS multidimensional pose-adjustable optical imaging devices, a signal transmission layer is directly integrated on the drive arm of the MEMS multidimensional pose-adjustable optical imaging device. This will cause the signal transmission layer and the electrothermal layer to generate a large parasitic capacitance, which will seriously interfere with the high-frequency signal transmission of the image sensor.

[0051] Introduction to the signal transmission layer on the drive arm: In existing technologies, Bimorph uses two layers of materials: Al and PSPI (ignoring the heating resistor Pt and the insulating layer silicon oxide). Al is a good conductor of electricity, and CIS signal output can be achieved by extending the two ends of the Al in the drive arm to the movable platform (image sensor assembly) and the substrate, respectively. However, while this structure has little impact on low-frequency DC signals during operation, it significantly affects the critical high-frequency signals used to transmit image information in the image sensor signal. When the signal transmission is a high-frequency signal, the image quality degrades or even fails to form a normal image. If the Al lead solution on the drive arm is not adopted, the image sensor packaged on the MEMS movable platform (image sensor assembly) needs to be led out through wire bonding, which reduces the integration of the entire device. Moreover, considering the subsequent packaging process (e.g., using flip-chip bonding to package the image sensor on the MEMS), directly using the Al leads integrated on the drive arm for signal output will greatly reduce the packaging steps and complexity.

[0052] This invention, by independently configuring the drive arm and flexible leads, with the flexible leads serving as the sole signal line, effectively avoids the impact of parasitic capacitance caused by the drive arm and signal transmission lines on image information transmission, thus improving image transmission quality. Simultaneously, the flexible leads solve the problems of large size, low integration, and difficult manufacturing processes resulting from wire bonding connections between the image sensor and the chip substrate. Therefore, this application ensures the integrity and quality of high-frequency image information transmission by adding flexible leads.

[0053] In existing technologies, MEMS multi-dimensional pose-tunable optical imaging devices employ electrostatic or piezoelectric actuation techniques to achieve in-plane and out-of-plane motion, and most utilize micro-assembly methods, resulting in non-integrated structures. Among existing actuation methods, electrostatic actuation suffers from instability due to the attraction effect caused by structural limitations, and the displacement is restricted by high driving voltages; piezoelectric actuation exhibits hysteresis due to material limitations, and the displacement is also relatively limited; electromagnetic actuation, while providing larger displacements, suffers from magnetic interference and large size due to its inherent limitations. Theoretical research and experimental measurements show that electrothermal actuation has the best displacement output capability among all actuation methods, achieving displacements on the order of hundreds of micrometers at low driving voltages. For applications requiring miniaturization, multiple degrees of freedom, and large displacements, using electrothermal MEMS actuation technology is a more feasible approach.

[0054] The electrothermal-driven MEMS multidimensional pose-adjustable optical imaging device of this application has a response speed that can meet the requirements of multidimensional motion in general scenarios such as non-high-speed scanning (<20 Hz). Considering the transmission problem of high-frequency signals from image sensors, we added a flexible lead structure to the traditional electrothermal structure for transmitting signals from the image sensor.

[0055] As an optional implementation, the deformable part has a five-layer structure: The first layer is a passivation layer made of silicon oxide, used to protect the subsequently deposited platinum metal (Pt) and electrically isolate it from the silicon in the SOI wafer device layer. The second layer is a heating resistor made of Pt metal, which uses the electrothermal effect to heat the drive arm by applying electricity to the metal. The third layer is an insulating layer made of silicon oxide, achieving electrical isolation between Pt and the subsequent Al. The fourth layer is a thin film of metallic Al. The last layer is a photosensitive polyimide (PSPI) film. Silicon oxide is a brittle material that will break under external force with even a small deformation (far less than 1%). However, polyimide is a high-molecular-weight polymer that can undergo large elastic and plastic deformations without breaking, and can better absorb and disperse impact energy. Silicon oxide has a very high Young's modulus, while polyimide has a very low Young's modulus. The high modulus makes the silicon oxide structure "hard and brittle," shattering directly like glass under impact. The low modulus makes the polyimide structure "soft and tough," and it will deform under impact, thus playing a buffering role. Therefore, the above material structure can greatly improve the reliability of MEMS multi-dimensional pose-adjustable optical imaging devices.

[0056] In existing technologies, the integrated signal lines of the drive arm can conduct signals from the image sensor using its own Al structure layer, aiming to both drive and conduct signals. However, as a layer of the deformation section, Al covers the entire deformation section, with a Pt metal layer underneath serving as a heating resistor, and silicon oxide acting as insulation between them, forming a large capacitor. Once the Al leads output high-frequency signals from the image sensor, due to the capacitor's characteristic of passing AC and blocking DC, the high-frequency signals will be drawn to the Pt heating resistor, resulting in significant losses.

[0057] Experiments have shown that the drive arm leads do not affect the DC and low-frequency signals of the image sensor. However, if high-frequency signals are connected to the drive arm leads, image information cannot be recognized. The flexible lead design avoids the large capacitance formed by Al and Pt, which can improve the problems of poor high-frequency signal quality and high signal transmission loss.

[0058] In one exemplary embodiment, the flexible lead includes a silicon oxide layer, a conductive signal line layer, and a flexible insulating base layer arranged sequentially; the flexible lead has a serpentine folding structure (planar serpentine structure) to provide sufficient deformation space and prevent the lead from breaking due to fatigue.

[0059] The silicon oxide layer of the flexible leads serves as a passivation layer to protect the subsequently deposited platinum metal Pt and form electrical isolation with the silicon in the SOI wafer device layer; the conductive signal line layer is made of metal Al, which has good conductivity and process compatibility; the flexible insulating base layer is photosensitive polyimide (PSPI), which has good flexibility, insulation and process compatibility.

[0060] The flexible leads are spatially isolated from the drive arm of the electrothermal drive signal processing module, thereby minimizing the parasitic capacitance between the conductive signal line layer and the electrothermal drive signal processing module.

[0061] In one exemplary embodiment, a MEMS multi-dimensional pose-adjustable optical imaging device is proposed. Both the adapter plate and the MEMS micro-motion platform are provided with multiple electrical lead connection points, which are used to connect the adapter plate and the MEMS platform.

[0062] The MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a drive signal processing module. The drive signal processing module is used to process and output drive signals to the drive arm, so that the deformable part of the drive arm extends and retracts and drives the micro-motion platform to move to the desired position.

[0063] The MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a position detection module; the MEMS multi-degree-of-freedom micro-motion chip is disposed on a bottom circuit board (in one embodiment, the chip substrate is disposed on the bottom circuit board, and the bottom circuit board includes structures corresponding to the micro-motion platform above and below).

[0064] The position detection module is used to: detect the current position of the image sensor component and send the current position to the drive signal processing module; the current position is used to calculate the drive signal during the focusing process.

[0065] In detecting the current position of the image sensor assembly, the position detection module is used to: Obtain the first capacitance between the micro-motion platform and the bottom circuit board.

[0066] The vertical distance between the bottom circuit board and the micro-motion platform is obtained based on the first capacitor.

[0067] The current position of the image sensor assembly is obtained based on the vertical distance, and the current position is the position of the image sensor assembly relative to the bottom circuit board.

[0068] This invention provides a capacitive position detection method, such as... Figure 8 As shown, the micro-motion platform is provided with a first low-resistivity silicon layer, which serves as the first electrode plate. Figure 8 In area A of the circuit board, a second electrode plate is disposed at the position opposite the micro-motion platform (preferably, the bottom circuit board is provided with a second low-resistivity silicon layer, which serves as the second electrode plate). Figure 8In region B, the first and second plates form a pair of plates in a capacitor. When voltage is applied to the heating drive arm, the deformation of the drive arm causes displacement of the image sensor assembly. This displacement leads to a change in the distance between the plates, thus changing the capacitance value. The initial value of the capacitance... C 0 is: ; In the formula, ε r The relative permittivity depends on the medium between the plates; ε 0 It is the absolute dielectric constant; S The area of ​​the electrode plate; d This is the vertical distance between the first and second plates.

[0069] In focusing mode, voltage is applied to the drive arm based on the electrothermal principle, causing the drive arm to deform (extend) and generate displacement (the relative positions of the two ends of the drive arm change, that is, the position of the image sensor component relative to the chip substrate changes), resulting in a change in capacitance. The position of the image sensor component is obtained by testing the capacitance value, and then the position of the image sensor component is controlled through closed-loop feedback, thereby achieving focusing. In detection mode, heat causes deformation of the drive arm, which in turn causes the position of the image sensor component to move. By detecting the capacitance value, the magnitude of the displacement can be determined, and thus the position information of the image sensor component can be obtained.

[0070] In one exemplary embodiment, the present invention provides a packaging method for a MEMS multi-dimensional pose-tunable optical imaging device. An image sensor is packaged on an adapter board. On the adapter board, signal processing and signal integration are performed on the signals of each pin of the image sensor to reduce the number of pins. The adapter board also includes surface-mount resistors and capacitors for subsequent reading of the raw signals from the image sensor. The image sensor is mounted via wire bonding (e.g., ...). Figure 5 (as shown) or flip-chip welding (e.g.) Figure 6 After the image sensor assembly (shown) is electrically connected to the adapter board, an image sensor assembly is formed. The image sensor assembly and the MEMS multi-degree-of-freedom micro-motion chip are then packaged. There are two packaging methods: One approach involves first releasing the MEMS multi-degree-of-freedom (MDOF) micro-motion chip (release is a process step using front-side dry etching, where the silicon beneath the movable part is etched away from the front, freeing the movable part from the constraint of the silicon substrate, allowing it to lift and move; this step is typically called the release device). Then, the image sensor assembly is packaged onto the released MDOF micro-motion chip. However, the MDOF micro-motion chip needs to be fixed during the packaging process. By precisely measuring the dimensions of the MDOF micro-motion chip, a corresponding mold can be designed and 3D printed to fix the released MDOF micro-motion chip.

[0071] Another approach involves first coating the image sensor with a protective film (using Parylene C as the thin-film protective material), then encapsulating the image sensor assembly with the micro-motion platform, and finally releasing the MEMS multi-degree-of-freedom micro-motion chip. The image sensor signal travels via gold wires to the pads on the micro-motion platform, and then through flexible leads to the corresponding pads on the chip substrate. Finally, the encapsulated MEMS multi-degree-of-freedom micro-motion chip is packaged on a pre-designed bottom circuit board. The image sensor signal and the MEMS drive signal are respectively wire-connected from the substrate pads to the bottom circuit board pads, with two interfaces for outputting the image sensor image information and the MEMS drive signal, respectively.

[0072] In an exemplary embodiment, the MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a drive signal processing module, which is used to: process and output drive signals to the drive arm, so that the deformable part of the drive arm extends and retracts and drives the micro-motion platform to move to the desired position.

[0073] The MEMS multi-dimensional pose-adjustable optical imaging device is rigidly connected to an inertial measurement unit, and the inertial measurement unit is electrically connected to the drive signal processing module.

[0074] The inertial measurement unit is used to detect the jitter direction and tilt angle of the MEMS multi-dimensional pose-adjustable optical imaging device.

[0075] The drive signal processing module is further configured to control the image sensor assembly to deflect along a direction opposite to the jitter direction by an angle equal to the size of the tilt angle, based on the jitter direction and tilt angle.

[0076] As one implementation, the rigid connection between the MEMS multi-dimensional pose-adjustable optical imaging device and an inertial measurement unit means that the chip substrate of the MEMS multi-dimensional pose-adjustable optical imaging device and the inertial measurement unit are relatively fixed in position.

[0077] The inertial measurement unit includes a gyroscope, accelerometer, etc. The inertial measurement unit is integrated with the MEMS multi-dimensional pose-adjustable optical imaging device into a system to detect the device's jitter and attitude, and assist in image stabilization and focusing.

[0078] In some embodiments, the inertial measurement unit may also be processed by other processors (the inertial measurement unit is not connected to the drive signal processing module, but is connected to an external processor). For example, it can be connected to the MEMS multi-dimensional pose-adjustable optical imaging device through other processors, and receive image or video frame signals transmitted by the image sensor component, as well as data such as angular velocity transmitted by the inertial measurement unit. After analysis and processing, control signals are output to the MEMS multi-dimensional pose-adjustable optical imaging device for driving.

[0079] In one exemplary embodiment, the principle of image stabilization is as follows: First, images are continuously captured using an optical imaging module. If there is camera shake during the exposure time, the point originally imaged on the image sensor will be imaged at a different point, resulting in image shift and reduced image sharpness. Image stabilization aims to reduce this image shift. Camera shake can be divided into two types: linear movement of the camera along its axis, called "translation"; and tilting of the camera around its axis, called "tilt." Within a sufficiently short exposure time, if the subject is far enough away, the effect of translation can be ignored, and only tilt shake needs to be considered.

[0080] Sensor-based image stabilization works by reversing the sensor's position, realigning the imaging light rays back to the sensor's center, and supporting pitch and yaw compensation. The specific steps are as follows: the camera's angular velocity is detected by the inertial measurement unit, the optical axis offset angle is calculated, and the sensor is reversed to achieve compensation.

[0081] Optical axis offset angle θ From angular velocity ω t The integral yields: ; Where t is the exposure time.

[0082] In one exemplary embodiment, an imaging system based on a MEMS multi-dimensional pose-adjustable optical imaging device is proposed, the imaging system including an optical lens group and the MEMS multi-dimensional pose-adjustable optical imaging device described in any of the preceding embodiments.

[0083] The MEMS multi-dimensional pose-adjustable optical imaging device is fixedly connected to the optical lens group, and the image sensor assembly is coaxial with the center of the optical lens group.

[0084] The optical lens assembly is used to transmit external light to the image sensor assembly.

[0085] In an exemplary embodiment (Embodiment A), a focusing system for a MEMS multidimensional pose-adjustable optical imaging device is proposed, including a processor and the MEMS multidimensional pose-adjustable optical imaging device described in any of the preceding embodiments.

[0086] The processor is used to acquire image information output by the flexible lead wire and process the image information to obtain focusing parameters; the focusing parameters are used to control the drive arm to move along the focusing direction so that the image sensor assembly can perform multi-dimensional motion.

[0087] In some embodiments, the focusing system of the MEMS multi-dimensional pose-adjustable optical imaging device further includes an optical lens group, the MEMS multi-dimensional pose-adjustable optical imaging device is fixedly connected to the optical lens group, and the image sensor assembly is coaxial with the center of the optical lens group.

[0088] The optical lens assembly is used to transmit external light to the image sensor assembly.

[0089] In an exemplary embodiment, a focusing system for a MEMS multi-dimensional pose-adjustable optical imaging device is proposed, which is the same as that in embodiment A, except that the processor includes an image processing module, a target detection and tracking module, a target area sharpness calculation module, and an image storage and display module.

[0090] The image processing module is used to: acquire image information output by the flexible lead wire, and send the image information to the target detection and tracking module; the image information is continuously captured images or videos.

[0091] The target detection and tracking module is used for: Extract target information from the image information, and filter out the targets to be tracked based on the target information.

[0092] The target to be tracked is processed to obtain tracking information, and the tracking information is sent to the target area sharpness calculation module; the tracking information includes all targets to be tracked, the focus area corresponding to each target to be tracked, and the image information.

[0093] The target area sharpness calculation module is used for: The tracking information is acquired, and based on the tracking information, the sharpness parameter of the target to be tracked in each focusing area is calculated to obtain the sharpness index of the target to be tracked in each focusing area.

[0094] When the sharpness index of the target to be tracked in the target focusing area meets the preset conditions, the target to be tracked corresponding to the target focusing area is marked as a tracked target, the image information of the target focusing area is marked as marked image information, and the tracked target is sent to the target detection and tracking module; the target focusing area is the focusing area corresponding to any target to be tracked.

[0095] The tracked targets are removed from all the targets to be tracked, leaving the remaining targets to be tracked.

[0096] When the number of remaining targets to be tracked is 0, all the marked image information is sent to the image processing module.

[0097] When the number of remaining targets to be tracked is not zero, for any remaining target to be tracked, the focusing parameters of the remaining target to be tracked are calculated, and the focusing parameters are input to the MEMS multi-dimensional pose-adjustable optical imaging device; the focusing parameters include focusing direction and change amount.

[0098] The image processing module is further configured to: when receiving the marked image sent by the target area sharpness calculation module, synthesize all the marked images to obtain a focused image, and transmit the focused image to the image storage and display module.

[0099] The focusing system based on the above-mentioned MEMS multi-dimensional pose-adjustable optical imaging device can realize image focusing. By directly driving the image sensor component through the MEMS multi-dimensional pose-adjustable optical imaging device, fast and precise focusing can be achieved. Moreover, the MEMS multi-dimensional pose-adjustable optical imaging device has a high degree of integration, which can make the space compact.

[0100] In one exemplary embodiment, the target detection and tracking module operates as follows: By analyzing continuously captured images using a target detector (such as YOLO), specific targets can be identified, and the output target bounding boxes can be used as initial references for subsequent tracking. For scenes without specific targets, inter-frame differencing or optical flow methods can be used to extract motion regions, and then clustering or connected component analysis can be used to determine the target to be tracked.

[0101] Once the target is initialized, the system switches to tracking mode and uses Kalman filtering to predict the target's position and motion state in subsequent frames. Kalman filtering is suitable for linear motion models and can effectively smooth the target's trajectory and reduce jitter. During tracking, the confidence level of the tracking results (such as the peak response of the correlation filter or the consistency score of the optical flow) is calculated in real time. If the confidence level is lower than the threshold, it is determined that the target may be lost or occluded. At this time, the target detector is triggered to re-detect the image and attempt to re-capture the target.

[0102] Once the target is detected, the target bounding box is used as the boundary of the focusing area.

[0103] In an exemplary embodiment, the working principle of the target area sharpness calculation module is as follows: during the movement of the image sensor assembly (for example, applying the same voltage to each drive arm to drive the image sensor to move gradually from bottom to top), continuous image information is acquired. For each image, the sharpness at different positions in the focus area is calculated. Based on the correspondence between the image information acquisition order and the sharpness, a sharpness curve can be plotted. The position of the image sensor assembly corresponding to the image information at the peak point in the curve is the focus position. The focus parameters are obtained based on the focus position.

[0104] In this embodiment, the Brenner gradient function is used to evaluate the sharpness of the target to be tracked. The Brenner function only considers the grayscale difference between the target point and a pixel that is two units away from it in the horizontal direction. It is simple, practical, and computationally inefficient. Its expression is: ; in f ( x , y ) represents the corresponding pixel in the image. x , y The grayscale value of ) f ( x +2, y ) represents the corresponding pixel in the image. x +2, y The grayscale value of ) is D(f), and the sharpness index of the target to be tracked is calculated.

[0105] In some embodiments, when the target region sharpness calculation module calculates the sharpness parameters of the target to be tracked, it can refer to the following indicators: gradient contrast, gray-level variance, and wavelet transform.

[0106] In some embodiments, the sharpness index of the target to be tracked in the target focusing area meets the preset conditions, which means that the calculated result value of the sharpness index of the target to be tracked meets the preset threshold conditions.

[0107] In an exemplary embodiment, the target area sharpness calculation module, in calculating the focusing parameters of any remaining target to be tracked, is configured to: Calculate the sharpness change of a first target in multiple consecutive images; the first target is any target to be tracked.

[0108] Based on the changes in sharpness, the direction and amount of focus adjustment are estimated.

[0109] As an alternative implementation, for an image with only one target, a hill-climbing algorithm is used to determine the image with the highest sharpness among multiple consecutive images of the target, which is considered to be in focus, and focusing is stopped.

[0110] This invention provides a MEMS multi-dimensional pose-adjustable optical imaging device and system, which uses flexible leads to achieve high-speed transmission of image information and uses a capacitive position detection method to provide feedback on the position of the movable platform (image sensor component). It also integrates functions such as focal plane modulation, optical image stabilization and tilt-shift photography. The purpose is to overcome the shortcomings of existing technologies and meet the needs of high dynamic scenes and high integration.

[0111] In the focusing system of the present invention, in addition to focal plane modulation, by placing the image sensor on a MEMS (MEMS multi-dimensional pose-adjustable optical imaging device), optical image stabilization and tilt-shift photography can also be achieved. Compared with existing methods for achieving optical image stabilization and tilt-shift photography with moving lenses, the focusing system of the present invention has no requirements for the lens and can be used with any lens.

[0112] In some embodiments, the image stabilization method may also be combined with electronic image stabilization, such as the meshflow algorithm and motion trajectory smoothing.

[0113] This invention is based on a MEMS multi-dimensional pose-adjustable optical imaging device and can also realize tilt-shift photography. Specifically, it includes the following steps (executed by the processor in Embodiment A): S100, acquire image information.

[0114] S200, calculate tilt parameters based on the image information. The tilt parameters are used to control the drive arm to move along the tilt direction so that the image sensor assembly can perform multi-dimensional motion, thereby changing the depth of field.

[0115] In this embodiment, the tilt-shift photography effect is achieved by driving the image sensor assembly. Driving the image sensor assembly to tilt keeps the lens center image distance constant, while the tilted imaging plane creates different image distances at different positions. By artificially creating a tilted depth-of-field region, the unique optical characteristics of a tilt-shift lens can be simulated, thus achieving the miniature landscape effect in tilt-shift photography. When two targets at different depths exist simultaneously in the field of view, their sharp images through the lens will fall on different focal planes. Tilting the imaging plane to match the focal plane allows both targets at different depths to be imaged clearly simultaneously in a single exposure.

[0116] By combining the aforementioned focusing system (focal plane modulation), image stabilization, and tilt-shift photography, the system achieves the best possible staring effect on the target, i.e., the clearest possible image of the target. Focal plane modulation ensures that light emitted from the subject, after passing through the lens, forms a clear image on the image sensor's imaging plane; optical image stabilization prevents blurring caused by camera shake; and tilt-shift photography enables multiple targets at different depths to be clearly imaged simultaneously.

[0117] In one exemplary embodiment, based on the same inventive concept, an imaging system based on a MEMS multi-dimensional pose-adjustable optical imaging device is also provided, including an optical lens group, any one of the above-mentioned MEMS multi-dimensional pose-adjustable optical imaging devices, and a host computer.

[0118] The host computer may include the processor in the above embodiments. The processor may include the image processing module, target detection and tracking module, target area sharpness calculation module and image storage and display module in the above embodiments. The host computer communicates with other parts of the imaging system.

[0119] The optical lens assembly controls the propagation path of light to meet imaging requirements.

[0120] The MEMS multi-dimensional pose-adjustable optical imaging device achieves three degrees of freedom of motion based on electrothermal actuation. Sixteen drive arms are arranged on a set of opposite sides of the image sensor assembly to provide sufficient driving force for piston-like translational displacement and rotation. The outer frame circuit board is fixed and rigidly connected to the optical lens assembly. The optical axis of the optical lens assembly is perpendicular to the plane of the MEMS multi-dimensional pose-adjustable optical imaging device. The image sensor assembly includes a PCB board and an image sensor, which is integrated on the PCB via wire bonding.

[0121] The drive arm operates to cause the image sensor assembly to move out of plane (along the optical axis of the lens group, i.e., Z-axis movement) and tilt (tilt relative to the surface where the chip substrate is located, i.e., pitch angle and yaw angle movement), with an out-of-plane displacement ≥100μm, thereby supporting focusing, optical image stabilization, and tilt-shift photography functions. The image sensor includes CMOS and CCD, and is not limited to visible light, but may also include infrared, ultraviolet, and ultrasonic imaging.

[0122] Optionally, the imaging system includes a scanning module, i.e., a galvanometer or MEMS micromirror, which adjusts the reflection angle to change the imaging field of view.

[0123] This invention addresses the challenges of miniaturizing and achieving high precision in optical stabilization and zoom functions within mobile device imaging systems. It proposes a multi-dimensional, pose-adjustable, high-precision, highly reliable, and miniaturized imaging device and system. It solves the problems of slow focal plane modulation response and limited focusing accuracy in traditional optoelectronic systems. Simultaneously, it achieves optical image stabilization and tilt-shift photography.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A MEMS multi-dimensional pose-adjustable optical imaging device, characterized in that, The MEMS multi-dimensional pose-adjustable optical imaging device includes a MEMS multi-degree-of-freedom micro-motion chip, an image sensor, and an adapter board. The image sensor is packaged in the adapter board to form an image sensor assembly, and the image sensor assembly is mounted on the MEMS multi-degree-of-freedom micro-motion chip. The MEMS multi-degree-of-freedom micro-motion chip includes a chip substrate, a micro-motion platform, and a driving component for connecting the chip substrate and the micro-motion platform; the driving component includes several driving arms and several flexible leads; the image sensor component outputs image information through the flexible leads and performs multi-degree-of-freedom motion through the driving arms; The micro-motion platform is supported and suspended by the drive assembly, and a number of drive arms and a number of flexible leads in the drive assembly are arranged around the micro-motion platform. The drive arm includes an anchoring structure, a deformation structure, and a connecting structure; one end of the deformation structure is fixedly connected to the chip substrate through the anchoring structure, and the other end of the deformation structure is connected to the micro-motion platform through the connecting structure.

2. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The deformable structure includes m L-shaped straight arms and m+1 deformable parts, where m≥2; The L-shaped straight arm includes a first rigid beam, a second rigid beam, and a right-angle transition zone connecting the first rigid beam and the second rigid beam; the extension direction of the first rigid beam and the extension direction of the second rigid beam are orthogonal to each other; One end of the first rigid beam of the first L-shaped straight arm is connected to the anchoring structure through the first deformation part, and the other end of the first rigid beam of the first L-shaped straight arm is connected to the other end of the second rigid beam of the first L-shaped straight arm through the right-angle transition area of ​​the first L-shaped straight arm. One end of the second rigid beam of the first L-shaped straight arm is connected to one end of the first rigid beam of the second L-shaped straight arm through the second deformation part. When m≥3, one end of the first rigid beam of the nth L-shaped straight arm is connected to one end of the second rigid beam of the (n-1)th L-shaped straight arm through the nth deformation part, and the other end of the first rigid beam of the nth L-shaped straight arm is connected to the other end of the second rigid beam of the nth L-shaped straight arm through the right-angle transition area of ​​the nth L-shaped straight arm. One end of the second rigid beam of the nth L-shaped straight arm is connected to one end of the second rigid beam of the (n+1)th L-shaped straight arm through the (n+1)th deformation part, 1<n<m; One end of the first rigid beam of the m-th L-shaped straight arm is connected to one end of the second rigid beam of the (m-1)-th L-shaped straight arm through the m-th deformation section. The other end of the first rigid beam of the m-th L-shaped straight arm is connected to the other end of the second rigid beam of the m-th L-shaped straight arm through the right-angle transition zone of the m-th L-shaped straight arm. One end of the second rigid beam of the m-th L-shaped straight arm is connected to the connecting structure through the (m+1)-th deformation section.

3. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The flexible lead contains at least one layer of conductive material, which is a metal or polycrystalline silicon.

4. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The flexible lead is folded.

5. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The image sensor is a CMOS image sensor or a CCD image sensor.

6. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The adapter board has multiple electrical connection points, which are used to make electrical connections with the image sensor.

7. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The adapter board has multiple passive components and electrical connections, which are used to configure the image sensor to achieve the imaging function.

8. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, Both the adapter board and the MEMS micro-motion platform are provided with multiple electrical lead connection points, which are used to connect the adapter board and the MEMS platform. The MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a driving signal processing module. The driving signal processing module is used to process and output driving signals to the driving arm, so that the deformable part of the driving arm can extend and retract and drive the micro-motion platform to move to the desired position. The MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a position detection module; the MEMS multi-degree-of-freedom micro-motion chip is mounted on the bottom circuit board; The position detection module is used to: detect the current position of the image sensor component and send the current position to the drive signal processing module; the current position is used to calculate the drive signal during the focusing process; In detecting the current position of the image sensor assembly, the position detection module is used to: Obtain the first capacitance between the micro-motion platform and the bottom circuit board; The vertical distance between the bottom circuit board and the micro-motion platform is obtained based on the first capacitor. The current position of the image sensor assembly is obtained based on the vertical distance, and the current position is the position of the image sensor assembly relative to the bottom circuit board.

9. The MEMS multi-dimensional pose-adjustable optical imaging device according to claim 1, characterized in that, The MEMS multi-dimensional pose-adjustable optical imaging device is electrically connected to a driving signal processing module. The driving signal processing module is used to process and output driving signals to the driving arm, so that the deformable part of the driving arm can extend and retract and drive the micro-motion platform to move to the desired position. The MEMS multi-dimensional pose-adjustable optical imaging device is rigidly connected to an inertial measurement unit, and the inertial measurement unit is electrically connected to the drive signal processing module. The inertial measurement unit is used to detect the jitter direction and tilt angle of the MEMS multi-dimensional pose-adjustable optical imaging device; The drive signal processing module is further configured to control the image sensor assembly to deflect along a direction opposite to the jitter direction by an angle equal to the size of the tilt angle, based on the jitter direction and tilt angle.

10. A focusing system based on a MEMS multi-dimensional pose-adjustable optical imaging device, characterized in that, The focusing system includes the MEMS multi-dimensional pose-adjustable optical imaging device and processor as described in any one of the preceding claims; The processor is used to acquire image information output by the flexible lead wire and process the image information to obtain focusing parameters; the focusing parameters are used to control the drive arm to move along the focusing direction so that the image sensor assembly can perform multi-dimensional motion.

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