Large-aperture MEMS Fabry-Perot infrared filter

Abstract

The invention belongs to the related technical field of optical micro electro mechanical systems, and discloses a large-aperture MEMS Fabry-Perot infrared filter, a cantilever beam reinforcing structure is innovatively introduced into a movable mirror structure, and a high-performance silicon carbide material is adopted for bonding reinforcement, so that the cavity length tuning range is greatly ensured, and meanwhile, the large-aperture MEMS Fabry-Perot infrared filter is obtained. The aperture of the filter is further increased, and the luminous flux of infrared radiation is enhanced.

Description

Technical Field

[0001] This invention belongs to the technical field of optical microelectromechanical systems, and more specifically, relates to a large-aperture MEMS Fabry-Perot infrared filter. Background Technology

[0002] With the rapid development of Micro-Electro-Mechanical Systems (MEMS) technology, MEMS Fabry-Pérot (FP) filters have emerged as a prominent focus due to their superior performance. They not only enable the fabrication of ultra-fine structures at the micrometer level but also possess characteristics such as high detection sensitivity, high integration, low power consumption, and ultra-thin thickness, demonstrating enormous potential in diverse scenarios including defense monitoring, industrial automation, and consumer electronics. Among them, cavity-length-tunable MEMS FP filters, with their flexible spectral control capabilities, play a crucial role in fields such as spectral analysis, optical signal processing, environmental sensing, and laser technology, becoming an important force driving the advancement of modern optoelectronic technology.

[0003] The MEMS FP filter structure mainly consists of a fixed mirror, a movable mirror, and a central support structure. The distance between the fixed and movable mirrors is the cavity length, which can be adjusted by applying electrostatic or electromagnetic forces. MEMS FP filters based on electromagnetic cavity length adjustment have limited applications due to their large area and bulky package (including magnets). In contrast, MEMS FP filters based on electrostatic cavity length adjustment rely on an electric field, resulting in almost no continuous current during steady-state operation. Power consumption can be as low as nanowatts (nW), with lower driving inertia and microsecond-level displacement speeds, meeting the requirements of high-speed wavelength switching. Furthermore, its movable component (the central reflector above the cantilever beam) achieves elastic deformation through the cantilever beam structure, enabling contactless actuation and effectively avoiding frictional losses, making it more suitable for long-term stable operation.

[0004] Chinese patent CN117008321A discloses a MEMS Fabry-Perot filter chip structure with a wide adjustable range. It includes a fixed mirror structure and a movable mirror structure connected above it, forming an FP resonant cavity. A top fixed structure is connected above the movable mirror structure, and a cavity exists between the top fixed structure and the movable mirror structure. By driving the movable mirror inward or outward under power, the cavity length of the Fabry-Perot cavity can be reduced or increased. However, this structure is a silicon-based device, inherently with low mechanical stability. Furthermore, due to its "sandwich" structure, with the movable mirror in the middle, the high-reflectivity and anti-reflection coatings deposited on the mirror are more prone to deformation due to the pressure difference between the two cavities, affecting the device's optical performance. Simultaneously, the movable mirror, which is more likely to malfunction and require repair or replacement, is located in the middle, making manufacturing more difficult and hindering subsequent device maintenance and repair. In addition, the complex structure places higher demands on the environment for stable device operation, significantly limiting application scenarios.

[0005] Chinese patent CN116661127A discloses an electromagnetic-electrostatic dual-drive Fabry-Perot filter chip and its fabrication method. It includes a movable mirror, a fixed mirror, a permanent magnet, a PCB circuit board, and a spacer layer. The movable mirror is provided with a detection electrode and a drive electrode, and the permanent magnet is embedded on the other end face. It can overcome the problems of nonlinear modulation and limited tuning range of single-drive Fabry-Perot filter chips. However, due to the inductive characteristics of the electromagnetic coil and the inertia of the mechanical parts, the response speed of the filter is relatively slow. Secondly, electromagnetically driven filters generate electromagnetic interference during operation, which may affect surrounding electronic equipment. They are also susceptible to external electromagnetic interference, leading to unstable filtering performance. Furthermore, the chip has a low first-order resonant frequency, making it prone to resonance at common external vibration excitation frequencies. This results in significant vibration amplitudes in the internal mechanical components of the filter, accelerating device wear and affecting the filter's performance and lifespan. Similarly, the device's 10mm aperture, within the far-infrared spectral response range, is still limited by diffraction effects and optical coupling efficiency, reducing its spatial sampling capability and energy focusing efficiency for long-wavelength photons. Consequently, the completeness of spectral information acquisition and processing accuracy are difficult to achieve ideal levels, thus its aperture has room for expansion.

[0006] In summary, existing technologies for large-aperture filters in the far-infrared band are limited, resulting in complex structures and performance that fails to meet requirements. The far-infrared band contains crucial information on object temperature and thermal distribution, making it essential for thermal imaging and monitoring in special environments. However, this band exhibits weak radiation energy, necessitating filters with large apertures to ensure greater infrared radiation transmission and thus improve sensor sensitivity and signal-to-noise ratio. However, designing large-aperture filters requires consideration not only of potential additional mirror weight, stress, and response speed, but also factors such as manufacturing process capabilities. Therefore, balancing the design of large-aperture far-infrared filters with appropriately extended cavity length tuning range while reducing manufacturing complexity has become a pressing technical challenge. Summary of the Invention

[0007] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a large-aperture MEMS Fabry-Perot infrared filter, which aims to solve the large-aperture problem of existing infrared filters.

[0008] To achieve the above objectives, this invention provides a MEMS Fabry-Perot far-infrared filter with a reinforced structure, including a fixed mirror structure and a movable mirror structure connected above it. The movable mirror structure and the fixed mirror structure together constitute an FP resonant cavity. The fixed mirror structure includes a first electrode, and the movable mirror structure includes a second electrode. When there is a potential difference between the first and second electrodes, the movable mirror structure shifts towards the fixed mirror structure, reducing the cavity length of the FP resonant cavity, thereby achieving cavity length tuning. The fixed mirror structure also includes a first silicon body structure. A first insulating dielectric layer is provided on the upper surface of the first silicon body structure. The first electrode is disposed on the first insulating dielectric layer and includes a first lead point and a connected first electrode sheet. A first high-reflectivity film is also provided on the first insulating dielectric layer, and the first high-reflectivity film is located inside the FP resonant cavity. An electrode is located outside the first high-reflectivity film; a first antireflective coating corresponding to the position of the first high-reflectivity film is provided on the lower surface of the first silicon body structure; the movable mirror structure also includes a second silicon body structure, which includes a movable body, a cantilever beam, a cantilever beam reinforcement structure, and a support body. A second insulating dielectric layer is provided on the lower surface of the movable body. The second electrode is disposed on the second insulating dielectric layer and includes a second lead point and a connected second electrode sheet. A second high-reflectivity film is also provided on the second insulating dielectric layer. The second high-reflectivity film is located inside the FP resonant cavity, and the second electrode is located outside the second high-reflectivity film. A second antireflective coating corresponding to the position of the second high-reflectivity film is provided on the upper surface of the movable body. The cantilever beam is located outside the movable body and remains suspended. The cantilever beam reinforcement structure is bonded above or below the cantilever beam. The support body is used to support the fixed mirror structure and the movable mirror structure.

[0009] Furthermore, the thickness of the cantilever beam is the same as the thickness of the movable body, but different from the thickness of the cantilever beam reinforcement structure. It is worth noting that the cantilever beam reinforcement structure can be bonded above or below the cantilever beam; its structural shape has no specific standard, as long as it can be bonded to the bend of the cantilever beam and the location of maximum stress at the connection with the intermediate reflector.

[0010] In summary, compared with the prior art, the large-aperture MEMS Fabry-Perot infrared filter provided by this invention has the following advantages:

[0011] 1. To optimize the dynamic performance of devices and enhance their stability under complex operating conditions, this invention innovatively introduces a cantilever beam reinforcement structure and employs high-performance silicon carbide (SiC) material for bonding strengthening. Silicon carbide, with its excellent mechanical properties—ultra-high elastic modulus and low density—significantly improves the overall structural stiffness after precise bonding with the original structure. This increases the device's first-order characteristic frequency, effectively reducing or avoiding resonance under dynamic loads or high-frequency excitation environments. It also reduces performance degradation and structural failure risks caused by vibration, resulting in a more stable operating state and significantly broadening application scenarios. Furthermore, the step-by-step low-temperature annealing technology achieves low-stress bonding between silicon carbide and silicon, ensuring good flatness of the bonded structure. Therefore, while maintaining a significantly wider cavity length tuning range, the filter aperture is further increased, facilitating enhanced absorption in the infrared band.

[0012] 2. This invention maximizes the light-transmitting aperture while maintaining a simple structural design. Through rational design of the device structure, the folding degree of the three cantilever beams, evenly distributed around the center point, is appropriately increased to ensure balanced support for the central reflector, while maintaining the flatness of the reflector during tuning. Furthermore, a stiffer silicon carbide material is bonded above the cantilever beams connected to the movable mirror, effectively increasing the first-order characteristic frequency of the device structure. This allows it to move away from the resonance range when subjected to external excitation, reducing displacement errors and structural fatigue risks caused by vibration. This results in more stable performance output in high-frequency operating scenarios or complex vibration environments, enhancing the device's mechanical stability. Compared to existing technologies, it overcomes the limitations of small aperture size, effectively increasing light throughput while maintaining high mechanical stability. With greater light throughput, this structure can receive significantly more information in the infrared band, thus achieving more efficient detection. In addition, this structure can achieve a wider tuning range in the far-infrared band. Attached Figure Description

[0013] Figure 1 This is an exploded view of the overall structure of the infrared filter structure provided by the present invention;

[0014] Figure 2 This is a schematic diagram of the infrared filter structure provided by the present invention;

[0015] Figure 3 This is a schematic diagram illustrating the working principle of the infrared filter structure provided by the present invention;

[0016] Figure 4 This is a simulation diagram of the tuning performance of the infrared filter structure provided by the present invention;

[0017] Figure 5 This is a schematic diagram of the cantilever beam structure related to the infrared filter structure provided by the present invention;

[0018] Figure 6 This is a simulation diagram of the electromechanical performance of the infrared filter structure provided by the present invention;

[0019] Figure 7 This is a before-and-after comparison of the change in the first characteristic frequency of the infrared filter structure provided by this invention before and after reinforcement with high-performance silicon carbide.

[0020] Figure 8 This is a schematic diagram of the characteristic frequencies of the infrared filter structure provided by the present invention when using silicon of the same thickness;

[0021] Figure 9 This is a schematic diagram of the fabrication method of the infrared filter structure provided in Embodiment 1 of the present invention;

[0022] Figure 10 This is a schematic diagram of the infrared filter structure and fabrication method provided in Embodiment 2 of the present invention;

[0023] In all the figures, the same reference numerals are used to denote the same elements or structures, wherein: 1-FP resonant cavity; 100-fixed mirror structure; 101-first silicon body structure; 102-first insulating dielectric layer; 103-first lead point; 104-first antireflection coating; 105-first high reflectivity coating; 106-first electrode sheet; 110-first electrode; 200-movable mirror structure; 201-second silicon body structure; 201a-movable body; 201b-cantilever beam; 201c-support body; 202-second lead point; 203-second electrode sheet; 204-second high reflectivity coating; 205-second antireflection coating; 210-second electrode; 206-cantilever beam reinforcement structure; 207-second insulating dielectric layer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0025] Figure 1 The large-aperture MEMS Fabry-Perot infrared filter structure (hereinafter referred to as FP structure) provided in Embodiment 1 of the present invention includes a fixed mirror structure 100 and a movable mirror structure 200, as well as a support body 201c connecting the fixed mirror structure and the movable mirror structure. The movable mirror structure 200 also includes a cantilever beam 201b, which contains a cantilever beam reinforcement structure 206. The thickness ratio of the movable mirror structure 200 to the cantilever beam reinforcement structure 206 is 3:1.

[0026] like Figure 2 As shown, in the above FP structure, the fixed mirror structure 100 has a first electrode 110, and the movable mirror structure 200 has a second electrode 210. When there is a potential difference between the first and second electrodes, the movable mirror structure 200 shifts towards the fixed mirror structure 100, and the cavity length of the FP cavity 1 shortens. The fixed mirror structure 100 includes a first silicon body structure 101. The upper surface of the first silicon body structure 101 is provided with a first insulating dielectric layer 102 and a first high-reflectivity film 105. The first high-reflectivity film 105 is located at the center of the first silicon body structure 101 to form a fixed mirror. The first electrode 110 is disposed on the first insulating dielectric layer 102, so that it is electrically isolated from the first silicon body structure 101 through the first insulating dielectric layer 102. The first electrode 110 includes a first lead point 103 and a connected first electrode plate 106. The first electrode plate 106 is located on the periphery of the first high-reflectivity film 105 and can generate a uniform electrostatic force with the second electrode 210. The movable mirror structure 200 includes a second silicon body structure 201, which includes a movable body 201a, a cantilever beam 201b, and a support body 201c. The support body 201c is connected to the movable body 201a via the cantilever beam 201b. A second high-reflectivity film 204 and a second insulating dielectric layer 207 are provided on the lower surface of the movable body 201a. A second lead point 202 is located on the second insulating dielectric layer 207 on the lower surface of the second silicon body structure 201, forming the second electrode 210 with the second electrode sheet 203. The movable body 201a serves as the light-transmitting area of ​​the movable mirror, with a second high-reflectivity film 204 on its lower surface and a second anti-reflection film 205 on its upper surface. A cantilever beam reinforcement structure 206 is bonded above the cantilever beam 201b.

[0027] When this structure is in operation, light enters from directly above the device, passes sequentially through the second antireflection film 205 and the light-transmitting area of ​​the movable body 201a, and enters the FP resonant cavity 1. Under the tuning effect of the FP resonant cavity 1, light of a specific wavelength passes through the light-transmitting area of ​​the first silicon bulk structure 101 and the first antireflection film 104 before exiting. Its working principle is as follows: When a plane light wave is incident perpendicularly into the FP cavity at a transmission angle of θ, the optical path difference between two adjacent transmitted beams is...

[0028] D=2nhcosθ

[0029] Phase difference is

[0030]

[0031] Where nh is the optical thickness of the FP cavity, and λ is the wavelength of the light wave in vacuum. Let the complex reflection coefficient and complex transmission coefficient of the light beam entering from the outside of the FP cavity be r and t, respectively, and the complex reflection coefficient and complex transmission coefficient exiting from the cavity be r' and t', respectively, and the amplitude of the incident light be A. (i) .

[0032] like Figure 3 As shown, each transmitted beam interferes at a point P' after passing through the FP cavity, forming a field as follows:

[0033]

[0034] Let be the nth transmitted light beam, where δ0 is the phase constant during light propagation, and ω is the angular frequency of the light wave. t Let P be the light propagation time, then the complex amplitude of the interference field of the transmitted light at point P' can be obtained:

[0035] A (t) =tt′{1+r ′2 exp(iδ)+r′ 4 exp(i2δ)+…+r′ 2(n-1) exp[i(n-1)δ]}A (i)

[0036] In the limiting case where the number of transmitted rays approaches infinity, we can obtain...

[0037]

[0038] Define the reflectivity of the FP cavity as R and the transmittance as T, then the above equation can be rewritten as follows:

[0039] At=T1-R2expiδAi

[0040] The intensity of the transmitted interference light at point P' is:

[0041]

[0042] Therefore, when the cavity length h of the FP cavity changes, its optical thickness nh changes accordingly, when the following condition is met:

[0043] δ=2mπm=0,1,2,…

[0044] At this time, the interference of transmitted light is enhanced, producing bright and fine fringes. The wavelength of the transmitted light at this time is λ. c for:

[0045]

[0046] That is, by changing the cavity length of the FP cavity, the wavelength band of light transmitted through the FP cavity can be filtered.

[0047] The optical performance of a field-sensitive (FP) cavity can be simulated using MATLAB software, allowing for the analysis of transmission spectrum changes during cavity length tuning. For example... Figure 4 As shown, the average peak transmittance can reach 89.5886% when the transmission peak is tuned within the range of 8 to 12 μm, indicating that the designed FP filter has good selective transmittance within the tuning range.

[0048] Example 1

[0049] This embodiment proposes a novel structure and uses COMSOL software to simulate the electromechanical performance of the device structure. By reasonably designing and appropriately increasing the aperture of the movable body 201a, the overall size reaches 40mm, the aperture of the movable body reaches 15mm, the cantilever beam width is 0.8mm, the silicon bulk structure thickness is 300μm, and the silicon carbide reinforcement structure thickness is 100μm. (See attached diagram for reinforcement structure.) Figure 5 The structure is a three-cantilever beam structure. 'a' represents the radius of movable body 201a, and 'b' represents the radius of the outer disk connecting movable body 201a and cantilever beam 201b. The three cantilever beams are evenly distributed around a central point. Each cantilever beam consists of a bridge-like structure connecting the inner and outer rings. Since the structural parameters of the three cantilever beams are identical, we will now describe the structure of one of them. Taking the cantilever beam in the lower right corner as an example, the beam extends from the w1 fan ring and is then formed by three beams, k1, k2, and k3, extending outwards. K1 and k2 are connected by fan ring w2, and K2 and k3 are connected by fan ring w3. Finally, k3 extends to connect with the outside through fan ring w4. The radius 'a' of movable body 201a is 7.5 mm, the outer disk radius 'b' is 11 mm, the central angle of fan ring w1 is 26°, the central angle of fan ring w2 is 20°, the central angle of fan ring w3 is 14°, and the central angle of fan ring w4 is 20°. The relevant parameters for the cantilever beam are shown in Table 1.

[0050] Table 1

[0051] structure Parameter (mm) <![CDATA[k1 inner diameter]]> 12.2 <![CDATA[Outer diameter of k1]]> 13 <![CDATA[Inner diameter of k2]]> 14 <![CDATA[Outer diameter of k2]]> 14.8 <![CDATA[k3 inner diameter]]> 15.6 <![CDATA[Outer diameter of k3]]> 16.4

[0052] The overall structure of the device is as follows Figure 6 As shown in (a); (b) and (c) show that the structure can drive the central movable body 201a to a displacement of 2.76μm at a voltage of about 41V, and according to the formula, it can be deduced that the structure's tuning range covers about 97.95% of the far-infrared band, realizing the function of wide-range tuning; (d) is a stress simulation of the structure during the tuning process, which can clearly observe the stress distribution of each part of the device structure during the driving process. The main stress-bearing parts of the structure are the cantilever beam and the junction between the cantilever beam and the intermediate movable body 201a, with a maximum stress of approximately 1.58 MPa. The yield strength of the bonding parts is mainly determined by the properties of the weaker material and the bonding strength of the bonding interface. According to the literature, the tensile stress of single-crystal silicon is between 70 and 150 MPa, while silicon carbide, due to its strong crystal structure with covalent bonds, can reach a tensile stress of 300 to 500 MPa. This demonstrates that the device can ensure that the structure will not undergo distortion and fracture during electrostatic driving. (e) Modal analysis of the structure was performed, focusing on the displacement deformation of the device in the first mode. The simulation showed that the first-order modal characteristic value of the device structure was 211.91 Hz, and the maximum displacement was 0.0566 μm. Figure 7 Table 2 shows the device structure without silicon carbide reinforcement. As can be seen, the first-order modal eigenvalue of the unbonded structure is 87.735 Hz, while (b) shows the device structure after silicon carbide bonding, with a first-order modal eigenvalue of 211.91 Hz, an improvement of 141.53%. The changes in device stability before and after reinforcement with silicon carbide are shown in Table 2.

[0053] Table 2

[0054] First characteristic frequency Second characteristic frequency Third characteristic frequency Before SiC reinforcement 87.735Hz 171.79Hz 172.09Hz SiC reinforcement 211.91Hz 419.79Hz 420.36Hz

[0055] To more clearly demonstrate the effect of silicon carbide hardening on the stability improvement of the device structure itself, Figure 8 The characteristic frequencies of the structure itself, using only silicon as the material, are shown at the same thickness (400 μm) as the hardened device structure. It can be found that the first characteristic frequency of the device is 108.31 Hz. Compared with the hardened structure, the first-order modal eigenvalue is improved by 95.65%, which verifies that the stability of the device is significantly improved after hardening.

[0056] As a preparation example provided by the present invention, Figure 9 The image shows a method for fabricating a filter:

[0057] (a) Silicon was selected as the substrate for fabricating the movable mirror body with a thickness of 300 μm. At the same time, a silicon carbide substrate with a thickness of 100 μm was selected. The thickness ratio of silicon to silicon carbide was 3:1. The two substrates were cleaned and dried respectively.

[0058] (b) Using deep reactive ion etching process, the silicon carbide layer is first etched to form the central reflector hollow area, and then constrained stepwise low temperature annealing is used to achieve low stress heterobonding of silicon carbide and silicon.

[0059] (c) A 100 nm thick gold layer was deposited by electron beam evaporation to fabricate a second electrode on the bonded Si bottom;

[0060] (d) A second mirror was fabricated on the movable mirror body using plasma-enhanced chemical vapor deposition (PEVCD) / ion beam assisted deposition (IBAD) technology;

[0061] (e) The corresponding area of ​​the movable mirror substrate is etched through by deep reactive ion etching process to create a cantilever beam;

[0062] (f) Select a silicon substrate with a thickness of 300 μm as the substrate for fabricating the fixed mirror body, and clean and dry the substrate;

[0063] (g) A 100 nm thick gold layer is deposited by electron beam evaporation to fabricate the first electrode on the fixed mirror substrate;

[0064] (h) A first reflecting mirror is fabricated on a fixed mirror substrate using plasma-enhanced chemical vapor deposition (PEVCD) / ion beam assisted deposition (IBAD) technology. The first and second reflecting mirrors each include a first high-reflectivity coating and a first anti-reflection coating, a second high-reflectivity coating, and a second anti-reflection coating, respectively. Both the first and second high-reflectivity coatings are 5-layer Ge / ZnS distributed Bragg mirrors with a refractive index ratio of Ge:ZnS = 4:2.2, a single Ge layer thickness of 691 nm, and a single ZnS layer thickness of 1325 nm. Both the first and second anti-reflection coatings are 5-layer YbF3 / ZnS films with a refractive index ratio of YbF3:ZnS = 1.52:2.2. A single YbF3 layer thickness of 1943 nm and a single ZnS layer thickness of 1325 nm are also included. Support pillars are fabricated on the fixed mirror substrate.

[0065] (i) After aligning the fixed mirror and the movable mirror with metal shims, they are bonded by hot pressing.

[0066] Example 2

[0067] The FP infrared filter structure and fabrication method proposed in this embodiment are as follows: Figure 10 As shown. With Figure 9 Unlike the previous example, the SiC-reinforced structure 206 is located on one side of the second electrode 210. The simulation results for this structure are the same as in Example 1, differing only in the fabrication method. This method includes the following steps:

[0068] (a) Silicon was selected as the substrate for fabricating the movable mirror body, and silicon carbide substrate was selected at the same time. The thickness ratio of silicon to silicon carbide was 3:1. The two substrates were cleaned and dried respectively.

[0069] (b) Using deep reactive ion etching process, the silicon carbide layer is first etched to form the central reflector hollow area, and then constrained stepwise low temperature annealing is used to achieve low stress heterobonding of silicon carbide and silicon.

[0070] (c) A gold layer is deposited by electron beam evaporation to fabricate a second electrode on the bonded SiC bottom;

[0071] (d) A second mirror was fabricated on the movable mirror body using plasma-enhanced chemical vapor deposition (PEVCD) / ion beam assisted deposition (IBAD) technology;

[0072] (e) The corresponding area of ​​the movable mirror substrate is etched through by deep reactive ion etching process to create a cantilever beam;

[0073] (f) Silicon is selected as the substrate for fabricating the fixed mirror body. The substrate is cleaned and dried.

[0074] (g) A gold layer is deposited by electron beam evaporation to fabricate a first electrode on a fixed mirror substrate;

[0075] (h) A first reflecting mirror is fabricated on a fixed mirror body using plasma-enhanced chemical vapor deposition (PEVCD) / ion beam assisted deposition (IBAD) technology; a support column is fabricated on the fixed mirror substrate;

[0076] (i) After aligning the fixed mirror and the movable mirror with metal shims, they are bonded by hot pressing.

[0077] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again" in this invention are intended to illustrate the invention and are not intended to limit the invention.

[0078] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A large aperture MEMS Fabry-Perot infrared filter comprising a fixed mirror structure (100) and a movable mirror structure (200) attached above it, the movable mirror structure (200) and the fixed mirror structure (100) together forming a FP resonator cavity (1), the fixed mirror structure (100) comprising a first electrode (110), the movable mirror structure (200) comprising a second electrode (210), the movable mirror structure (200) being deflected towards the fixed mirror structure (100) when a potential difference exists between the first and second electrodes, the cavity length of the FP resonator cavity (1) being reduced, characterized in that, The fixed mirror structure (100) further comprises a first silicon body structure (101), a first insulating medium layer (102) is arranged on the upper surface of the first silicon body structure (101), the first electrode (110) is arranged on the first insulating medium layer (102), a first high-reflection film (105) is further arranged on the first insulating medium layer (102), and the first high-reflection film (105) is located in the FP resonant cavity (1); the first electrode (110) is located outside the first high-reflection film (105); a first anti-reflection film (104) corresponding to the position of the first high-reflection film (105) is arranged on the lower surface of the first silicon body structure (101); the movable mirror structure (200) further comprises a second silicon body structure (201), the second silicon body structure (201) comprises a movable body (201a), a cantilever beam (201b), a cantilever beam reinforcing structure (206) and a support body (201c), a second insulating medium layer (207) is arranged on the lower surface of the movable body (201a), the second electrode (210) is arranged on the second insulating medium layer (207), a second high-reflection film (204) is further arranged on the second insulating medium layer (207), the second high-reflection film (204) is located in the FP resonant cavity (1), and the second electrode (210) is located outside the second high-reflection film (204); a second anti-reflection film (205) corresponding to the position of the second high-reflection film (204) is arranged on the upper surface of the movable body (201a); the cantilever beam (201b) is located outside the movable body (201a) and remains suspended, and the cantilever beam reinforcing structure (206) is bonded above or below the cantilever beam (201b); the support body (201c) is used for supporting the fixed mirror structure (100) and the movable mirror structure (200).

2. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The material of the cantilever beam reinforcing structure (206) is silicon carbide.

3. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The thickness of the cantilever beam (201b) is the same as the thickness of the movable body (201a) and is different from the thickness of the cantilever beam reinforcing structure (206).

4. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The cantilever beam (201b) is a horizontally central symmetric structure, comprising three cantilever beams uniformly distributed along the circumference, and each cantilever beam is folded inward.

5. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The first electrode (110) comprises a first lead point (103) and a first electrode sheet (106) connected with the first lead point (103).

6. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The second electrode (210) comprises a second lead point (202) and a second electrode sheet (203) connected with the second lead point (202).

7. The large-aperture MEMS Fabry-Perot infrared filter of claim 1, wherein, The caliber of the movable body (201a) is 15 mm.

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