Annular layered stacked high-reliability MEMS fast mirror packaging structure

Abstract

The application discloses a high-reliability MEMS fast mirror packaging structure with a ring-shaped layered stack, and relates to the technical field of micro-electro-mechanical system (MEMS) fast mirrors. The application discloses a high-reliability MEMS fast mirror packaging structure with a ring-shaped layered stack, and relates to the technical field of micro-electro-mechanical system (MEMS) fast mirrors. The application discloses a high-reliability MEMS fast mirror packaging structure with a ring-shaped layered stack, and relates to the technical field of micro-electro-mechanical system (MEMS) fast mirrors.

Description

Technical Field

[0001] This invention relates to the field of microelectromechanical systems (MEMS) fast reflector technology, and in particular to a ring-shaped, layered, stacked, high-reliability MEMS fast reflector packaging structure. Background Technology

[0002] MEMS fast-reflecting mirrors are miniature optical actuators based on silicon-based micro-nano fabrication technology. They are fabricated on a single-crystal silicon wafer, integrating an ultra-thin reflective mirror, an elastic support cantilever, and electrostatic / piezoelectric driving electrodes. By applying an electrical signal to change the cantilever deformation, they can drive the micron-level reflective mirror to achieve high-speed two-dimensional deflection, enabling precise scanning, deflection, and modulation of laser beams. In the past decade, industries such as automotive LiDAR, indoor 3D sensing, automotive HUD laser projection, space laser communication, infrared medical scanning, and industrial machine vision inspection have entered a stage of large-scale application, directly driving the explosive growth in demand for MEMS fast-reflecting mirrors. Compared to traditional mechanical scanning devices such as galvanometers and polygonal rotating mirrors, MEMS fast-reflecting mirrors possess core advantages such as miniaturization, low power consumption, high scanning frequency, fast response speed, and low mass production cost, making them a core optical path component in various miniaturized optical scanning devices.

[0003] The existing technical solution in the industry is: a single metal pressure ring + a single-layer integrated light-shielding bracket semi-stacked MEMS fast-reflecting mirror package. This solution is currently the mainstream mass production solution for mid-range industrial 3D sensing equipment. It is also the only packaging structure in the existing technology that simultaneously possesses the four major features of "layered stacking, top ring pressing, light-shielding bracket, and optical protection window". It has the most extensive patent and mass production applications.

[0004] In the existing technical solution's complete hierarchical structure (from bottom to top):

[0005] Printed Circuit Board (PCB): As the underlying carrier, the MEMS fast reflector chip is directly surface-mounted and soldered to the center area of ​​the PCB. Small, thin mounting tabs extend from the four corners of the PCB, with screw holes for securing the entire device. There is no independent, thickened support base. Gold fingers are led out from the side for signal and power transmission.

[0006] MEMS fast reflector chip: It is completely flat and bonded to the PCB pads, with no isolation layer on the bottom surface. It is only limited by a simple single-layer bracket inner wall around the perimeter, without full-circumference rigid constraint.

[0007] Top metal retaining ring: A single ring-shaped metal sheet is placed on the upper surface of the optical lens; through holes are opened at the four corners of the retaining ring, and four locking screws are used to lock it downwards to the mounting ears of the PCB. The lens is pressed down by the pre-tightening force of the screws to achieve clamping and fixing of all components.

[0008] However, existing technical solutions still have structural defects:

[0009] 1. Defects in load-bearing structure: There is no independent mounting base, and the entire load of the machine is borne by the PCB.

[0010] Existing product structural features: Locking holes are only opened on thin lugs extending from the edge of the printed circuit board; there is no dedicated rigid support base. All equipment installation torque and long-term vibration and impact loads act directly on the thin PCB material. Derivative disadvantages: 1) After locking, the PCB is prone to warping and bending deformation, which is directly transmitted to the onboard MEMS chip, causing plastic deformation of the micromirror and zero-point drift during scanning; 2) The PCB has extremely low bending and torsional stiffness, and the module's inherent resonant frequency is low, making it prone to resonance with vibration sources in automotive and industrial equipment, amplifying alternating stress and accelerating fatigue fracture of the MEMS cantilever; 3) The PCB material has weak impact resistance; under drop conditions, the circuit board is prone to cracking, and chip pads may detach and break.

[0011] 2. Defects in chip stress isolation structure: Only a single-layer light-shielding bracket, without an independent chip fixing buffer frame.

[0012] Existing product structure characteristics: MEMS chips are directly laid flat and soldered onto the PCB surface, with only a simple single-layer injection-molded bracket for enclosure, without an independent wrap-around limiting buffer frame. Derivative disadvantages: 1) Thermal stress from temperature changes and mechanical stress from assembly clamping on the PCB are directly transmitted to the MEMS micro-cantilever due to the lack of a transition buffer structure. After high and low temperature cycling, the mirror zero point drifts significantly, requiring frequent recalibration of the optical path; 2) The chip lacks full-circumference rigid constraint, allowing it to slide back and forth on the PCB surface under lateral vibration, continuously pulling on the bonding wires. Long-term alternating stress causes fatigue fracture of the wires; 3) The single-layer light-shielding channel cannot effectively block the two independent light leakage gaps at the bottom of the lens and the sidewall of the chip. Multiple reflections of stray light inside the package result in poor signal-to-noise ratio of the scanning spot and ghosting defects in the imaging.

[0013] 3. Defects in the locking and fixing system: It uses a one-way open-loop pressure ring clamping mechanism and lacks a two-way closed-loop clamping structure.

[0014] Existing product structure characteristics: It relies solely on a single metal pressure ring at the top to apply downward pressure, without a matching base for reverse support at the bottom, and relies on screws to attach to the PCB earpieces to form a one-way clamping. Derivative disadvantages: 1) Under long-term high and low temperature and vibration environments, the screw preload continuously decreases, the pressure ring clamping force decreases, internal lens and bracket components loosen and slip, and the beam scanning trajectory deviates; 2) The concentrated downward pressure in one direction causes localized stress concentration in the bracket and lens, which can easily lead to lens edge chipping and bracket cracking after long-term use; 3) Without a sealing barrier formed by the bonding of multiple parts, it relies only on a small amount of adhesive for sealing, and the adhesive has capillary gaps, allowing dust and moisture to easily penetrate the encapsulation and contaminate the MEMS reflective surface.

[0015] 4. Defects in layered integrated assembly structure: The components are assembled in steps without an integrated stacking and limiting structure.

[0016] Existing product structure features: the pressure ring, lens, single-layer bracket, and PCB are completely independent components, requiring step-by-step gluing and curing during assembly. Derivative disadvantages: 1) Complex assembly process, multiple gluing and curing cycles, resulting in low production efficiency and high labor costs; 2) Uncontrollable alignment errors during step-by-step assembly, leading to large variations in optical path coaxiality, optical clearance, and light-blocking effect within the same batch of products, resulting in poor consistency in optical performance; 3) Lack of layer-by-layer positioning and limiting structures, making parts prone to misalignment during assembly, requiring individual optical path calibration for each module, and resulting in high mass production calibration costs.

[0017] Therefore, based on the above-mentioned technical problems, those skilled in the art urgently need to develop a ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure. Summary of the Invention

[0018] The purpose of this invention is to provide a ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure to solve the above-mentioned problems.

[0019] To achieve the above objectives, the present invention provides the following technical solution:

[0020] The present invention provides a ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure, comprising:

[0021] The components assembled from bottom to top are: mounting base, printed circuit board, chip mounting frame, MEMS chip, mirror, and upper cover.

[0022] The mounting base at the bottom and the upper cover at the top are locked together to rigidly press the printed circuit board, chip fixing frame, MEMS chip, and mirror surface to form a complete closed-loop module. The chip fixing frame is used to support the peripheral non-functional edge of the MEMS chip, and the central mirror surface and the micron-level elastic cantilever are completely suspended.

[0023] Furthermore, the mounting base is a bottom-level load-bearing reference component, and the mounting base is an annular disc-shaped rigid base.

[0024] Furthermore, the printed circuit board is an irregularly shaped FR-4 substrate with a PCB circuit layer, the side of the printed circuit board has gold finger signal cables, and the surface of the printed circuit board has reserved bonding pads for the MEMS chip.

[0025] Furthermore, the printed circuit board is horizontally attached to the support surface of the mounting base, and the mounting base is provided with multi-level annular positioning steps corresponding to the outer contour notch of the printed circuit board, so that the printed circuit board is laid flat and positioned within the positioning steps of the mounting base.

[0026] Furthermore, the chip fixing frame has an inner cavity that covers and limits the MEMS chip, which is used to make the optical path coaxial, isolate the thermal deformation stress of the PCB circuit layer, suppress zero-point drift, block lateral stray light from the side wall, wrap the MEMS chip to buffer the bonding wires, and prevent the wires from being pulled and broken.

[0027] Furthermore, the chip fixing frame engages with the center light-transmitting window of the PCB circuit layer of the printed circuit board.

[0028] Furthermore, the MEMS chip is a single-crystal silicon chip with the mirror and a micron-level elastic cantilever at its center.

[0029] Furthermore, the MEMS chip receives electrical signals to drive micron-level elastic cantilever deformation, thereby causing the mirror surface to deflect in two dimensions.

[0030] Furthermore, the inner cavity in the middle of the chip fixing frame is a hollow structure to support only the outer non-functional edge of the MEMS chip, and the mounting base and printed circuit board below are both light-transmitting hollow structures so that the mirror at the center position is completely suspended from the micron-level elastic cantilever.

[0031] Furthermore, the upper pressure cover is an annular pressure cover with a light-transmitting window in the center, used to press and fix it on the mounting base. The upper pressure cover closes with the mounting base and presses the printed circuit board, chip fixing frame, MEMS chip, and mirror to limit the radial sliding of the mirror.

[0032] In the above technical solution, the ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure provided by the present invention has the following beneficial effects:

[0033] The entire load is completely isolated, preventing PCB deformation from damaging the chip. Existing solutions rely on PCB thin plate tabs to lock the entire device, which causes the circuit board to warp under stress. The deformation stress directly causes permanent deformation and zero-point drift of the micro-cantilever. This invention has an independent rigid base that bears all external loads, and the PCB does not participate in the stress at all, eliminating optical path deviation and microstructure plastic failure from the root.

[0034] The bidirectional closed-loop locking ensures stable clamping force and prevents component slippage over a long period. Traditional unidirectional pressure rings experience screw preload decay due to long-term temperature changes and vibrations, leading to lens and bracket slippage. The concentrated pressure in one direction can also cause lens edge chipping. This invention features bidirectional rigid clamping, with multiple planes evenly distributing the pressure stress. Each step provides omnidirectional limiting, eliminating the risk of optical path drift during long-term use.

[0035] The overall rigidity of the module is improved, avoiding resonance fatigue failure. Traditional single-layer thin-walled brackets have poor bending resistance and low resonance frequency, making them prone to resonance with vehicle and industrial equipment vibrations, accelerating microstructure fatigue fracture. The six-layer ring composite frame and thickened base of this invention significantly improve the overall rigidity, raise the natural resonance frequency, avoid the normal vibration range of the equipment, and significantly extend the vibration resistance and drop resistance life.

[0036] The chip features full-circumference rigid restraint, effectively protecting the bonding wires. Existing chips only have simple enclosures, allowing continuous slippage and pulling of the gold wires under lateral vibration, leading to wire breakage due to long-term alternating stress. This invention's fully enclosed fixing frame restricts chip displacement in all directions, significantly reducing alternating tensile stress on the leads and extending device lifespan. Attached Figure Description

[0037] 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 recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0038] Figure 1 This is a schematic diagram of a ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure provided in an embodiment of the present invention.

[0039] Figure 2 This is an exploded view of a ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure provided in an embodiment of the present invention.

[0040] Explanation of reference numerals in the attached figures:

[0041] 1. Mounting base; 2. Printed circuit board; 3. Chip mounting frame; 4. MEMS chip; 5. Mirror surface; 6. Top cover. Detailed Implementation

[0042] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0043] Please see Figure 1-2 A ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure, comprising:

[0044] The components assembled from bottom to top are: mounting base 1, printed circuit board 2, chip fixing frame 3, MEMS chip 4, mirror 5, and upper cover 6. In this six-layer structure, the upper and lower closed-loop stacking, bidirectional mechanical locking between mounting base 1 and upper cover 6, multi-layer stress buffering, and double-layer light-shielding MEMS fast-reflecting mirror integrated packaging structure are achieved. The whole adopts a coaxial ring-level matching design.

[0045] The mounting base 1 at the bottom and the upper cover 6 at the top are locked together to rigidly press the printed circuit board 2, the chip fixing frame 3, the MEMS chip 4, and the mirror 5 to form a complete closed-loop module. The chip fixing frame 3 is used to support the outer non-functional edge of the MEMS chip 4, and the central mirror and the micron-level elastic cantilever are completely suspended.

[0046] The solution integrates seven major functions: whole machine installation support, PCB circuit support, MEMS chip limit buffer, optical gap precise distance control, layered stray light shielding, external optical protection, and overall mechanical locking. It solves the inherent defects of traditional MEMS fast-reflecting mirror packaging from four dimensions: mechanical load-bearing, optical accuracy, environmental reliability, and mass production assembly. It is suitable for high-vibration and wide-temperature-range precision scanning scenarios such as automotive LiDAR, industrial 3D scanning, and space optical communication.

[0047] The standardized layer-by-layer assembly process for this structure is as follows:

[0048] Bottom layer pre-installation: The printed circuit board 2 is placed into the mounting base 1 positioning step to complete the bottom layer circuit positioning;

[0049] Chip assembly: The chip fixing frame 3 engages with the PCB center, and the MEMS chip 4 is embedded in the inner cavity of the chip fixing frame 3 for limiting.

[0050] Overall locking: The upper pressure cover 6 is aligned and locked with the mounting base 1, and the six-layer components are rigidly clamped together;

[0051] Auxiliary sealing: Only a small amount of adhesive is applied to the outer edge of the module for dust prevention, and the internal fixation relies entirely on mechanical compression. The adhesive does not bear any load.

[0052] Core working principle: The mechanical closed-loop force principle, the mounting base 1 supports upward and the upper pressure cover 6 presses downward to form an integral rigid outer frame, all locking, impact and vibration loads are borne by the rigid outer ring; the multi-layer steps limit each other, the impact energy is absorbed layer by layer, and there is no single point stress overload.

[0053] In the principle of coaxial automatic assembly, all parts are matched with ring positioning steps and stacked layer by layer to automatically align coaxially. This eliminates the need for repeated manual calibration of the optical path, significantly reduces assembly errors, and ensures the consistency of the optical path for batch products.

[0054] This solution enhances mechanical reliability by using an independent base to isolate external loads, thus addressing failures such as PCB deformation, chip pressure loss, lead wire breakage, and zero-point drift. In terms of mass production advantages, the integrated stepped stacking automatically aligns the components, eliminating the need for multiple dispensing and curing processes and repeated optical path calibration, simplifying the production process and resulting in lower performance dispersion and greater consistency in batch products.

[0055] Furthermore, mounting base 1 serves as the underlying load-bearing reference component, and is a ring-shaped rigid base. Specifically, mounting base 1 has symmetrical locking holes on its outer ring, and multiple annular positioning steps at the upper end, with its outer contour perfectly matching the upper pressure cover 6. Mounting base 1 is made of aluminum alloy (low expansion, high bending resistance). Functionally, it bears all loads from locking, vibration, and impact of the entire machine, and isolates the PCB from stress; the steps limit the PCB and provide reverse support to achieve bidirectional closed-loop locking; after assembly, it serves as the support reference for all upper components, with the printed circuit board 2 laid flat within the positioning steps of mounting base 1.

[0056] Furthermore, printed circuit board 2 is an irregularly shaped FR-4 substrate with a PCB circuit layer. Gold finger signal cables are located on the side of printed circuit board 2, and bonding pads for MEMS chip 4 are reserved on the surface of printed circuit board 2. The outer contour of printed circuit board 2 matches the steps of mounting base 1, and printed circuit board 2 supports the upper chip fixing frame 3.

[0057] Furthermore, the printed circuit board 2 is horizontally attached to the support surface of the mounting base 1. The mounting base 1 is configured with multi-level annular positioning steps corresponding to the outer contour notch of the printed circuit board 2, so that the printed circuit board 2 is laid flat and positioned within the positioning steps of the mounting base 1.

[0058] Furthermore, the chip fixing frame 3 has an inner cavity that covers and limits the MEMS chip 4, so as to make the optical path coaxial, isolate the thermal deformation stress of the PCB circuit layer, suppress zero drift, block lateral stray light from the side wall, wrap the MEMS chip 4 to buffer the bonding wires, and prevent the wires from being pulled and broken.

[0059] Furthermore, the chip mounting frame 3 is engaged with the central light-transmitting window of the PCB circuit layer of the printed circuit board 2. The chip mounting frame 3 is made of low-stress silicon material, and its sidewalls seal the lateral light leakage gap between the PCB and the MEMS chip 4. The chip mounting frame 3 can also be made of a material with a CTE close to that of silicon (such as Kovar alloy, low-expansion ceramics, or silicon-based frames), forming a first-order match with a small CTE difference with the silicon chip, directly reducing the thermal stress at the chip bonding interface.

[0060] The CTE mismatch stress between the printed circuit board and the mounting base is transferred to the outer frame structure and will not directly act on the MEMS chip. The thermal stress peak is buffered in stages and transferred outward, and the residual stress level inside the chip is significantly reduced.

[0061] Furthermore, the MEMS chip 4 is a single-crystal silicon chip with a mirror 5 and a micron-level elastic cantilever at its center.

[0062] Furthermore, the MEMS chip 4 receives electrical signals to drive the micron-level elastic cantilever deformation, thereby causing the mirror 5 to deflect in two dimensions and completing the laser beam scanning modulation.

[0063] Furthermore, the inner cavity of the chip mounting frame 3 is a hollow structure to support only the outer non-functional edges of the MEMS chip 4, and the mounting base 1 and printed circuit board 2 below are both light-transmitting hollow structures, so that the central mirror 5 and the micron-level elastic cantilever are completely suspended. The bonding interface is only distributed at the chip edge. The shrinkage stress of the adhesive layer and the interface thermal stress are confined to the periphery of the chip and cannot be directly transmitted to the central optical functional area, which greatly reduces the impact of residual stress on the mirror surface shape and cantilever stiffness, and avoids mirror warping and resonant frequency drift. At the same time, the bonding area of ​​traditional full-bottom surface patch is equal to the total area of ​​MEMS chip 4. The total stress generated by the curing shrinkage of the adhesive layer is large, and the poor uniformity of adhesive application can easily cause asymmetric stress. This structure only bonds the MEMS chip 4 at the contact area with the chip mounting frame 3, which greatly reduces the bonding area and the amount of adhesive used, directly reducing the total residual stress caused by the curing shrinkage of the adhesive layer; at the same time, the stress distribution of the frame-shaped bonding is more circumferentially symmetrical, reducing the interaxial crosstalk and mirror tilting problems caused by off-center load stress.

[0064] Furthermore, the upper pressure cover 6, a ring-shaped cover with a light-transmitting window at its center, is used to press and fix it onto the mounting base 1. The upper pressure cover 6 closes with the mounting base 1 and presses against the printed circuit board 2, chip fixing frame 3, MEMS chip 4, and mirror 5 to restrict the radial sliding of the mirror 5, and the window edge retaining ring blocks external stray light from entering. The upper pressure cover 6 covers the top of the stacked components, and the lower step presses against the outer ring of the lens, with its edge locked and fixed to the base. In this structure, the overall assembly and fixation are achieved through the mechanical locking of the upper pressure cover 6 and the mounting base 1. Adhesive bonding only serves to position the chip and provide auxiliary fixation, without relying on a large area of ​​adhesive layer to provide all the bonding force. Therefore, a low-shrinkage adhesive can be selected, and a thinner adhesive layer can be used to further reduce the curing shrinkage stress of the adhesive layer; at the same time, the stress distribution of mechanical pressing is more uniform, avoiding local stress concentration and bubble defects caused by uneven dispensing process. Overall, the core idea of ​​this structure is "stress outward shift and sensitive area unloading", which transfers the area of ​​residual stress from the chip's optical functional area to the peripheral non-optical frame structure, making it very suitable for high-precision optical devices such as MEMS fast-reflecting mirrors that are extremely sensitive to micro-stress.

[0065] In another embodiment, in the alternative connection structure between the upper pressure cover 6 and the mounting base 1, the mounting base 1 and the upper pressure cover 6 can be replaced with a snap-on type, a threaded tightening type, or an interference fit type bidirectional locking structure, in addition to screw locking, all of which can achieve closed-loop rigid clamping.

[0066] Among the alternative materials, the mounting base 1 and the upper pressure cover 6 can be replaced with low-expansion Kovar alloy and high-rigidity ceramic; the chip fixing frame 3 can be replaced with low-expansion ceramic and Kovar alloy.

[0067] In the overall stacking deformation scheme, the layer order is adjusted (only the integration method of PCB and base is changed), while retaining the three core innovations of base force, bidirectional locking, and chip limiting, which still fall within the protection scope of this invention.

[0068] In summary, this solution has the following beneficial effects:

[0069] The entire load is completely isolated, preventing PCB deformation from damaging the chip. Existing solutions rely on PCB thin plate tabs to lock the entire device, which causes the circuit board to warp under stress. The deformation stress directly causes permanent deformation and zero-point drift of the micro-cantilever. This invention has an independent rigid base that bears all external loads, and the PCB does not participate in the stress at all, eliminating optical path deviation and microstructure plastic failure from the root.

[0070] The bidirectional closed-loop locking ensures stable clamping force and prevents component slippage over a long period. Traditional unidirectional pressure rings experience screw preload decay due to long-term temperature changes and vibrations, leading to lens and bracket slippage. The concentrated pressure in one direction can also cause lens edge chipping. This invention features bidirectional rigid clamping, with multiple planes evenly distributing the pressure stress. Each step provides omnidirectional limiting, eliminating the risk of optical path drift during long-term use.

[0071] The overall rigidity of the module is improved, avoiding resonance fatigue failure. Traditional single-layer thin-walled brackets have poor bending resistance and low resonance frequency, making them prone to resonance with vehicle and industrial equipment vibrations, accelerating microstructure fatigue fracture. The six-layer ring composite frame and thickened base of this invention significantly improve the overall rigidity, raise the natural resonance frequency, avoid the normal vibration range of the equipment, and significantly extend the vibration resistance and drop resistance life.

[0072] The chip features full-circumference rigid restraint, effectively protecting the bonding wires. Existing chips only have simple enclosures, allowing continuous slippage and pulling of the gold wires under lateral vibration, leading to wire breakage due to long-term alternating stress. This invention's fully enclosed fixing frame restricts chip displacement in all directions, significantly reducing alternating tensile stress on the leads and extending device lifespan.

[0073] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A ring-shaped, layered, stacked, high-reliability MEMS fast-reflection mirror packaging structure, characterized in that, include: The components assembled from bottom to top are: mounting base (1), printed circuit board (2), chip fixing frame (3), MEMS chip (4), mirror (5), and upper cover (6). The mounting base (1) at the bottom and the upper cover (6) at the top are locked together to rigidly press the printed circuit board (2), the chip fixing frame (3), the MEMS chip (4), and the mirror (5) to form a complete closed-loop module. The chip fixing frame (3) is used to support the peripheral non-functional edge of the MEMS chip (4), and the central mirror and the micron-level elastic cantilever are completely suspended.

2. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 1, characterized in that, The mounting base (1) is the bottom bearing reference component, and the mounting base (1) is an annular disk-shaped rigid base.

3. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 1, characterized in that, The printed circuit board (2) is an irregular FR-4 substrate with a PCB circuit layer. The side of the printed circuit board (2) has gold finger signal lines. The surface of the printed circuit board (2) is reserved for bonding pads of the MEMS chip (4).

4. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 3, characterized in that, The printed circuit board (2) is horizontally attached to the support surface of the mounting base (1). The mounting base (1) is configured with multiple levels of annular positioning steps corresponding to the outer contour notch of the printed circuit board (2) so that the printed circuit board (2) is laid flat and positioned within the positioning steps of the mounting base (1).

5. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 3, characterized in that, The chip fixing frame (3) has an inner cavity that covers and limits the MEMS chip (4) to make the optical path coaxial, isolate the thermal deformation stress of the PCB circuit layer, suppress zero drift, block lateral stray light from the side wall, wrap the MEMS chip (4) to buffer the bonding wires, and prevent the wires from being pulled and broken.

6. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 5, characterized in that, The chip fixing frame (3) is engaged with the light-transmitting window at the center of the PCB circuit layer of the printed circuit board (2).

7. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 5, characterized in that, The MEMS chip (4) is a single-crystal silicon chip with the mirror (5) and a micron-level elastic cantilever at its center.

8. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 7, characterized in that, The MEMS chip (4) receives electrical signals to drive the micron-level elastic cantilever deformation, so that the mirror (5) is deflected in two dimensions.

9. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 7, characterized in that, The inner cavity of the chip fixing frame (3) is a hollow structure to support only the outer non-functional edge of the MEMS chip (4), and the mounting base (1) and printed circuit board (2) below are both light-transmitting hollow structures so that the mirror (5) at the center position is completely suspended from the micron-level elastic cantilever.

10. The ring-shaped layered stacked high-reliability MEMS fast-reflection mirror packaging structure according to claim 1, characterized in that, The upper cover (6) is an annular cover with a light-transmitting window in the center, which is used to press and fix it on the mounting base (1). The upper cover (6) closes with the mounting base (1) and presses the printed circuit board (2), chip fixing frame (3), MEMS chip (4), and mirror (5) to limit the radial sliding of the mirror (5).

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