A multispectral filter and a preparation method thereof, and an image acquisition device
By integrating a multispectral filter into the camera module and adjusting the cavity length of the Fabry-Perot resonator using control electrodes, the problem of difficult integration of traditional filter films is solved, thereby improving the multispectral shooting effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHEJIANG CRYSTAL OPTECH
- Filing Date
- 2022-03-21
- Publication Date
- 2026-05-29
AI Technical Summary
Traditional multispectral filters are difficult to integrate into camera modules and produce poor image quality.
A multispectral filter is used, including a first light-transmitting plate, a reflective layer, a Fabry-Perot resonant cavity, and a second light-transmitting plate. The cavity length is adjusted by controlling the electrodes to achieve multispectral filtering characteristics, and it is integrated with the camera module.
It fulfills the requirements for multispectral filtering, reduces costs, and enhances the multispectral shooting capabilities of the camera.
Smart Images
Figure CN114690301B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of image acquisition technology, and more specifically, to a multispectral filter and its preparation method, and an image acquisition device. Background Technology
[0002] With the rapid development of technology, the application of imaging devices has become quite common. In order to enable imaging devices to achieve multispectral imaging, the traditional method is to integrate a glass plate with a multispectral filter film in front of the CMOS or CCD imaging chip or to integrate an RGB photoresist array on the surface of the imaging chip to achieve the capture of red, green and blue three-spectrum images.
[0003] However, traditional methods suffer from the problem that the filter film is difficult to integrate into the camera module, and the shooting effect is poor. Summary of the Invention
[0004] The purpose of this application is to address the shortcomings of the prior art by providing a multispectral filter and its preparation method, as well as an image acquisition device, to solve the problems that existing filter films are difficult to integrate into camera modules and have poor shooting effects.
[0005] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:
[0006] One aspect of this application provides a multispectral filter, comprising: a first light-transmitting plate and a first reflective layer, a Fabry-Perot resonant cavity, a second reflective layer, and a second light-transmitting plate sequentially disposed on the first light-transmitting plate, wherein control electrodes are respectively disposed on the first light-transmitting plate and the second light-transmitting plate for adjusting the cavity length of the Fabry-Perot resonant cavity.
[0007] Optionally, the first reflective layer and / or the second reflective layer are distributed Bragg reflective layers.
[0008] Optionally, the Fabry-Perot resonator is made of polydimethylsiloxane.
[0009] Optionally, the control electrode includes a transparent conductive layer disposed on the first light-transmitting plate and the second light-transmitting plate, respectively, with the transparent conductive layer located on the side surface of the first light-transmitting plate and the second light-transmitting plate near the Fabry-Perot resonator.
[0010] Optionally, the multispectral filter further includes a through-hole extending through the first and / or second light-transmitting plates; the control electrode further includes conductive silicon filling the through-hole and connected to the corresponding transparent conductive layer.
[0011] Optionally, the multispectral filter further includes a back electrode disposed on the side surface of the first and second light-transmitting plates opposite to the Fabry-Perot resonator, respectively. The back electrode on the first light-transmitting plate is connected to the control electrode on the first light-transmitting plate, and the back electrode on the second light-transmitting plate is connected to the control electrode on the second light-transmitting plate.
[0012] Optionally, the resistivity of conductive silicon is less than 2 mΩ·cm.
[0013] Another aspect of this application provides a method for fabricating a multispectral filter, the method comprising: providing a first light-transmitting plate and a second light-transmitting plate respectively provided with control electrodes; forming a first reflective layer on the first light-transmitting plate on which the control electrodes are formed; forming a second reflective layer on the second light-transmitting plate on which the control electrodes are formed; coating a Fabry-Perot resonator on the first reflective layer; and bonding the second reflective layer to the Fabry-Perot resonator to obtain a first prefabricated device.
[0014] Optionally, providing a first light-transmitting plate and a second light-transmitting plate, each having a control electrode, includes: providing a first silicon substrate and a second silicon substrate; forming grooves and cylindrical conductive silicon within the grooves on the surfaces of the first and second silicon substrates respectively by etching; providing glass plates that close the grooves on one side surface of the first and second silicon substrates respectively; heating the glass plates to melt and fill the grooves in the first and second silicon substrates respectively; thinning the first and second silicon substrates on both sides respectively so that the glass plates filled in the grooves are exposed at the bottom of the grooves and the cylindrical conductive silicon covered by the glass plates are exposed, to obtain the first light-transmitting plate and the second light-transmitting plate; forming transparent conductive layers on one side surface of the first and second light-transmitting plates respectively, the transparent conductive layer on the first light-transmitting plate and the conductive silicon on the first light-transmitting plate being connected to serve as control electrodes on the first light-transmitting plate, and the transparent conductive layer on the second light-transmitting plate and the conductive silicon on the second light-transmitting plate being connected to serve as control electrodes on the second light-transmitting plate.
[0015] Optionally, after providing a first light-transmitting plate and a second light-transmitting plate respectively provided with control electrodes, the method further includes: forming back electrodes on the side surfaces of the first light-transmitting plate and the second light-transmitting plate opposite to the Fabry-Perot resonator, wherein the back electrode on the first light-transmitting plate is connected to the control electrode on the first light-transmitting plate, and the back electrode on the second light-transmitting plate is connected to the control electrode on the second light-transmitting plate.
[0016] In another aspect of the embodiments of this application, an image acquisition device is provided, including any of the above-described multispectral filters.
[0017] The beneficial effects of this application include:
[0018] This application provides a multispectral filter and its fabrication method, as well as an image acquisition device, comprising: a first light-transmitting plate and a first reflective layer, a Fabry-Perot resonator, a second reflective layer, and a second light-transmitting plate sequentially disposed on the first light-transmitting plate. Control electrodes are respectively disposed on the first and second light-transmitting plates for adjusting the cavity length of the Fabry-Perot resonator. By changing the voltage through the two control electrodes, the cavity length of the Fabry-Perot resonator is correspondingly changed, thereby achieving optical filtering characteristics across multiple wavelengths to meet multispectral filtering requirements. Furthermore, by integrating these components into a single multispectral filter, it is easy to directly integrate the multispectral filter with a camera module through voltage adjustment and reasonable device design, forming a modular product, reducing costs, and improving the multispectral shooting capabilities of the camera. Attached Figure Description
[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is one of the schematic diagrams showing the fabrication state of a multispectral filter provided in an embodiment of this application;
[0021] Figure 2 This is the second schematic diagram of the fabrication state of a multispectral filter provided in the embodiments of this application;
[0022] Figure 3 This is the third schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0023] Figure 4 This is the fourth schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0024] Figure 5 Fifth schematic diagram of the fabrication state of a multispectral filter provided in the embodiments of this application;
[0025] Figure 6 This is the sixth schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0026] Figure 7 This is the seventh schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0027] Figure 8 This is the eighth schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0028] Figure 9 A schematic diagram of the fabrication state of a multispectral filter provided in this application embodiment;
[0029] Figure 10 This is the tenth schematic diagram illustrating the fabrication state of a multispectral filter provided in this application embodiment;
[0030] Figure 11 This is eleventh of a schematic diagram illustrating the fabrication state of a multispectral filter provided in an embodiment of this application.
[0031] Figure 12 This is a schematic diagram of the structure of a multispectral filter provided in an embodiment of this application;
[0032] Figure 13 This is a schematic diagram of the fabrication process of a multispectral filter provided in an embodiment of this application;
[0033] Figure 14 A schematic diagram illustrating the application of this application for a multispectral filter under different voltages;
[0034] Figure 15 This is a schematic diagram illustrating the filtering characteristics of a multispectral filter under different voltages, provided in an embodiment of this application.
[0035] Figure 16 This is a schematic diagram of the structure of an image acquisition device provided in an embodiment of this application.
[0036] Icons: 100-First silicon substrate; 101-Groove; 102-Conductive silicon; 110-Mask; 130-Glass plate; 131-First light-transmitting plate; 132-Second light-transmitting plate; 140-Transparent conductive layer; 150-First reflective layer; 160-Back electrode; 170-Fabry-Perot resonator; 180-Second reflective layer; 200-Camera module; 210-Image sensor; 220-Multispectral filter; 230-Lens; 240-Drive circuit; 250-Controller; 260-Digital image memory; 270-Light ray. Detailed Implementation
[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, 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, not all embodiments. Generally, in the absence of conflict, the various features in the embodiments of this application can be combined with each other, and the combined embodiments are still within the protection scope of this application. It should be noted that similar reference numerals and letters in the following drawings indicate similar items. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0038] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and therefore should not be construed as limiting this application. Furthermore, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.
[0039] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0040] One aspect of this application provides a multispectral filter, such as... Figure 12 As shown, it includes: a first light-transmitting plate 131, a first reflective layer 150, a Fabry-Perot resonant cavity 170, a second reflective layer 180, and a second light-transmitting plate 132. The first reflective layer 150, the Fabry-Perot resonant cavity 170, the second reflective layer 180, and the second light-transmitting plate 132 are sequentially arranged on the first light-transmitting plate 131. At the same time, a control electrode is arranged on the first light-transmitting plate 131, and a control electrode is also arranged on the second light-transmitting plate 132. That is, the two control electrodes are located on opposite sides of the Fabry-Perot resonant cavity 170.
[0041] Since the cavity length of the Fabry - Perot resonator 170 can change the filtering characteristics, in actual use, the cavity length of the Fabry - Perot resonator 170 can be controlled by control electrodes respectively provided on the first light - transmitting plate 131 and the second light - transmitting plate 132. That is, by changing the voltage applied to the Fabry - Perot resonator 170 by the control electrodes provided on the first light - transmitting plate 131 and the second light - transmitting plate 132, the Fabry - Perot resonator 170 can be deformed, and then the cavity length of the Fabry - Perot resonator 170 can be changed. In other words, by the cavity lengths under different voltage levels and properties (repulsion: positive or negative voltages are applied to both side electrodes, like - charged electrodes repel each other, or attraction: different polarities are applied to both side electrodes, one positive and one negative, so that opposite - charged electrodes attract each other), the multi - spectral filter can achieve the optical filtering characteristics of multiple bands. For example Figure 14 as shown in (a) to (d) in, voltages V4, V3, V2, V1 with opposite polarities are respectively applied to the control electrodes at both ends of the multi - spectral filter, where V1 < V2 < V3 < V4, combined with Figure 15 shown, due to the gravitational force, the cavity length of the Fabry - Perot resonator becomes shorter from long, and its spectral filtering characteristics approach from near - infrared to ultraviolet, and the transmittance is relatively high in each band.
[0042] During use, the light beam can be incident from the first light - transmitting plate 131, and after passing through the first reflective layer 150, the Fabry - Perot resonator 170 and the second reflective layer 180, it exits from the second light - transmitting plate 132. By adjusting the cavity length of the Fabry - Perot resonator 170, the effect of filtering light beams of different spectra can be achieved.
[0043] In summary, in this application, by changing the voltage through two control electrodes, the cavity length of the Fabry - Perot resonator 170 is correspondingly changed, and then the optical filtering characteristics of multiple bands are achieved, meeting the multi - spectral filtering requirements. At the same time, by integrating to form an integrated multi - spectral filter, it is also convenient for the multi - spectral filter to be directly integrated with the camera module through voltage and reasonable device design (through the control electrodes, it can be more conveniently connected to the driving circuit during the assembly process of the camera module), forming a modular product, reducing costs, and enhancing the multi - spectral shooting ability of the camera.
[0044] Optionally, the first reflective layer 150 is a distributed Bragg reflector.
[0045] Optionally, the second reflective layer 180 is a distributed Bragg reflector.
[0046] Optionally, the Fabry-Perot resonator 170 is made of polydimethylsiloxane (PDMS), which gives the Fabry-Perot resonator 170 a low Young's modulus so that it can follow voltage changes and have different deformations, thereby enabling adjustment of the cavity length of the Fabry-Perot resonator 170.
[0047] Optional, such as Figure 12 As shown, for the control electrode on the first light-transmitting plate 131: the control electrode includes a transparent conductive layer 140 disposed on the first light-transmitting plate 131. The transparent conductive layer 140 is disposed on the side surface of the first light-transmitting plate 131 near the Fabry-Perot resonant cavity 170. In other words, the transparent conductive layer 140 is located between the first light-transmitting plate 131 and the first reflective layer 150.
[0048] Please continue to refer to Figure 12 Regarding the control electrode on the second light-transmitting plate 132: the control electrode also includes a transparent conductive layer 140 disposed on the second light-transmitting plate 132. The transparent conductive layer 140 is disposed on the side surface of the second light-transmitting plate 132 near the Fabry-Perot resonant cavity 170. In other words, the transparent conductive layer 140 is located between the second light-transmitting plate 132 and the second reflective layer 180.
[0049] Therefore, the cavity length of the Fabry-Perot resonator 170 located between the first reflective layer 150 and the second reflective layer 180 can be adjusted accordingly through the transparent conductive layer 140. At the same time, the light transmission effect of the transparent conductive layer 140 can also facilitate the normal transmission of the light beam.
[0050] In some implementations, such as Figure 12 As shown, by forming a whole layer of transparent conductive layer 140 on the surfaces of the first light-transmitting plate 131 and the second light-transmitting plate 132 respectively, the cavity length of the Fabry-Perot resonant cavity 170 can be adjusted more uniformly, thereby maintaining the consistency of the filtering characteristics of each part.
[0051] In some embodiments, the transparent conductive layer 140 may be indium tin oxide (ITO).
[0052] Optional, such as Figure 12 As shown, the multispectral filter also includes a through hole penetrating the first light-transmitting plate 131. The control electrode located on the first light-transmitting plate 131 also includes a conductive silicon 102 filling the through hole of the first light-transmitting plate 131. The conductive silicon 102 is connected to the transparent conductive layer 140 disposed on the first light-transmitting plate 131. In this way, the transparent conductive layer 140 located between the first light-transmitting plate 131 and the first reflective layer 150 can be led out to the back side of the first light-transmitting plate 131 by using the conductive silicon 102, which facilitates subsequent power connection.
[0053] Similarly, such as Figure 12As shown, a through hole is also provided on the second light-transmitting plate 132. The control electrode on the second light-transmitting plate 132 also includes conductive silicon 102 filled in the through hole of the second light-transmitting plate 132. In this way, the transparent conductive layer 140 located between the second light-transmitting plate 132 and the second reflective layer 180 can be led out to the back of the second light-transmitting plate 132 by means of conductive silicon 102, which facilitates subsequent power connection.
[0054] The conductive silicon 102 filled in the through-hole can be used as an embedded conductive silicon, which can be more conveniently connected to the drive circuit during the assembly of the camera module.
[0055] In some embodiments, both the first light-transmitting plate 131 and the second light-transmitting plate 132 are made of glass. Therefore, when conductive silicon 102 is placed in the through holes of both, since the conductive silicon 102 and glass are of similar material, a high-quality structure can be formed. Specifically:
[0056] First, silicon and glass have similar hardness, so when performing relatively flat surface processing, it is easier to process them into a plane, for example, the height difference between them can be less than 100nm.
[0057] Secondly, silicon and glass can adhere well, thus maintaining good adhesion and airtightness even when the pressure difference between the two sides of the glass is greater than 5 atmospheres.
[0058] Third, since silicon and glass are similar materials and have similar coefficients of thermal expansion, they can still form a good bond even in heat-resistant environments.
[0059] Fourth, it has good resistance to chemical corrosion.
[0060] Optional, refer to Figure 12 As shown, the multispectral filter also includes a back electrode 160 disposed on the side surface of the first light-transmitting plate 131 and the second light-transmitting plate 132 opposite to the Fabry-Perot resonator 170. In other words, a back electrode 160 is disposed on the back surface of the first light-transmitting plate 131 and the back surface of the second light-transmitting plate 132. The back electrode 160 on the first light-transmitting plate 131 is connected to the control electrode on the first light-transmitting plate 131, and the back electrode 160 on the second light-transmitting plate 132 is connected to the control electrode on the second light-transmitting plate 132. The back electrode 160 facilitates circuit connection during the integration of the multispectral filter.
[0061] Optionally, the resistivity of conductive silicon 102 is less than 2 mΩ·cm, thus achieving better conductivity. For example, the resistivity can be reduced by heavily doping the silicon material with phosphorus or boron.
[0062] Another aspect of this application provides a method for fabricating a multispectral filter, such as... Figure 13 As shown, the method includes:
[0063] S010: Provide a first light-transmitting plate 131 and a second light-transmitting plate 132 respectively provided with control electrodes.
[0064] S020: A first reflective layer 150 is formed on the first light-transmitting plate 131 on which control electrodes are formed.
[0065] S030: A second reflective layer 180 is formed on the second light-transmitting plate 132 on which the control electrode is formed.
[0066] S040: A Fabry-Perot resonant cavity 170 is coated on the first reflective layer 150.
[0067] S050: The second reflective layer 180 is bonded to the Fabry-Perot resonator 170 to obtain the first prefabricated device.
[0068] In summary, this application changes the voltage through two control electrodes, thereby changing the cavity length of the Fabry-Perot resonator 170 accordingly, thus achieving optical filtering characteristics across multiple wavelengths and meeting multispectral filtering requirements. Furthermore, by integrating these components into a single multispectral filter, the filter can be directly integrated with the camera module through voltage and appropriate device design (the control electrodes facilitate easy connection to the drive circuit during camera module assembly), forming a modular product, reducing costs, and enhancing the camera's multispectral shooting capabilities.
[0069] Optionally, the preparation process will be further illustrated below with examples:
[0070] like Figure 1 As shown, a first silicon substrate 100 is provided, and a mask 110 is formed on the surface of the first silicon substrate 100. The mask 110 is patterned by photolithography; then as... Figure 2 As shown, a groove 101 and a columnar conductive silicon 102 located within the groove 101 are formed on the surface of the first silicon substrate 100 by plasma deep silicon etching; as Figure 3 As shown, remove mask 110; Figure 4 As shown, a glass plate 130 is anoly bonded to the surface of the first silicon substrate 100, such that the glass plate 130 completely seals the groove 101; as Figure 5 As shown, the glass plate 130 is heated to melt and fill the interior of the groove 101. At this time, the glass plate 130 covers the cylindrical conductive silicon 102; as Figure 6As shown, by double-sided thinning and polishing of the upper and lower surfaces of the first silicon substrate 100, the glass plate 130 filled in the groove 101 is exposed on the back side of the first silicon substrate 100. Simultaneously, the columnar conductive silicon 102 covered by the glass plate 130 is also exposed on the front side of the first silicon substrate 100. The remaining glass plate 130, filling the groove 101, serves as the first light-transmitting plate 131. Figure 7 As shown, a transparent conductive layer 140 is formed on one side surface of the first light-transmitting plate 131. The transparent conductive layer 140 and the exposed cylindrical conductive silicon 102 are connected as control electrodes of the first light-transmitting plate 131, thereby obtaining the following... Figure 7 The first light-transmitting plate 131 with control electrodes is shown. (Refer to...) Figures 1 to 7 A second light-transmitting plate 132 with a control electrode is obtained. That is, the first light-transmitting plate 131 with a control electrode and the second light-transmitting plate 132 with a control electrode have the same structure and the same preparation process.
[0071] like Figure 8 As shown, a first reflective layer 150 is deposited on the transparent conductive layer 140 of the first light-transmitting plate 131 with control electrodes. Similarly, a second reflective layer 180 (not shown in the figure) is deposited on the transparent conductive layer 140 of the second light-transmitting plate 132 with control electrodes.
[0072] like Figure 9 As shown, a back electrode 160 is formed on the back of the first light-transmitting plate 131 with control electrodes by photolithography, vapor deposition, and stripping, and is connected to the columnar conductive silicon 102 in the first light-transmitting plate 131.
[0073] like Figure 10 As shown, a Fabry-Perot resonant cavity 170 is coated on the first reflective layer 150.
[0074] like Figure 11 As shown, the second light-transmitting plate 132 is bonded to the side surface of the Fabry-Perot resonator 170 opposite to the first light-transmitting plate 131, and the second reflective layer 180 of the second light-transmitting plate 132 is bonded to the surface of the Fabry-Perot resonator 170.
[0075] like Figure 12 As shown, a multispectral filter is formed by cutting and removing the surrounding silicon substrate material.
[0076] In some implementations, such as Figure 4 As shown, when the glass plate 130 is bonded to the surface of the first silicon substrate 100, it can be done in a vacuum environment, so that the first silicon substrate 100 seals the groove 101, thereby forming a vacuum-like environment in the groove 101, so that the air pressure inside the groove 101 is less than the air pressure outside the groove 101. Thus, when heating, the glass plate 130 can be fully filled into the groove 101 under the action of the internal and external pressure difference.
[0077] In another aspect of this application, an image acquisition device is provided, including any of the above-mentioned multispectral filters. Thus, by changing the voltage through two control electrodes, the cavity length of the Fabry-Perot resonator 170 is changed accordingly, thereby achieving optical filtering characteristics in multiple bands and meeting the filtering requirements of multispectral filters. At the same time, by integrating to form an integrated multispectral filter, the multispectral filter can be directly integrated with a camera module through voltage and reasonable device design to form an image acquisition device. This modularizes the image acquisition device, reduces costs, and improves the multispectral shooting capability of the image acquisition device.
[0078] like Figure 16 The diagram illustrates an image acquisition device including a camera module 200, a controller 250, a digital image memory 260, and a driving circuit 240. The camera module 200 includes an image sensor 210, a multispectral filter 220, and a lens 230. During assembly, the lens 230 is located on the light-receiving side of the image sensor 210, and the multispectral filter 220 is located between the lens 230 and the image sensor 210. Thus, after light 270 enters from the receiving side of the camera module 200, it passes sequentially through the lens 230 and the multispectral filter 220 to reach the image sensor 210, thereby achieving image acquisition by the camera module 200. The controller 250 is electrically connected to both the image sensor 210 and the driving circuit 240. Since the multispectral filter 220 uses control electrodes to achieve multispectral filtering, it is easily integrated with the driving circuit 240, and the voltage applied to it is controlled by the controller 250. The digital image memory 260 is electrically connected to the image sensor 210.
[0079] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A multispectral filter, characterized in that, include: A first light-transmitting plate and a first reflective layer, a Fabry-Perot resonant cavity, a second reflective layer, and a second light-transmitting plate are sequentially disposed on the first light-transmitting plate. Control electrodes are respectively disposed on the first light-transmitting plate and the second light-transmitting plate. The voltage applied to the Fabry-Perot resonant cavity by the control electrodes is adjusted to adjust the cavity length of the Fabry-Perot resonant cavity. The Fabry-Perot resonant cavity is made of polydimethylsiloxane; The control electrode includes a transparent conductive layer disposed on the first light-transmitting plate and the second light-transmitting plate respectively, the transparent conductive layer being located on the side surface of the first light-transmitting plate and the second light-transmitting plate near the Fabry-Perot resonant cavity.
2. The multispectral filter as described in claim 1, characterized in that, The multispectral filter further includes a through-hole extending through the first light-transmitting plate and / or the second light-transmitting plate; the control electrode further includes conductive silicon filling the through-hole and connected to the corresponding transparent conductive layer.
3. The multispectral filter as described in claim 2, characterized in that, The multispectral filter further includes back electrodes respectively disposed on the side surfaces of the first and second light-transmitting plates opposite to the Fabry-Perot resonant cavity. The back electrode on the first light-transmitting plate is connected to the control electrode on the first light-transmitting plate, and the back electrode on the second light-transmitting plate is connected to the control electrode on the second light-transmitting plate.
4. The multispectral filter as described in claim 2, characterized in that, The resistivity of the conductive silicon is less than 2 mΩ·cm.
5. The multispectral filter as described in claim 1, characterized in that, The first reflective layer and / or the second reflective layer are distributed Bragg reflective layers.
6. A method for fabricating a multispectral filter, characterized in that, The method is used to prepare the multispectral filter according to any one of claims 1 to 5, the method comprising: A first light-transmitting plate and a second light-transmitting plate, each respectively equipped with control electrodes, are provided; A first reflective layer is formed on a first light-transmitting plate on which control electrodes are formed; A second reflective layer is formed on a second light-transmitting plate on which control electrodes are formed; A Fabry-Perot resonant cavity is coated on the first reflective layer; The second reflective layer is bonded to the Fabry-Perot resonator to obtain the first prefabricated device.
7. The method for fabricating a multispectral filter as described in claim 6, characterized in that, The provision of a first light-transmitting plate and a second light-transmitting plate, each having a control electrode, includes: Provide a first silicon substrate and a second silicon substrate; Grooves and columnar conductive silicon within the grooves are formed on the surfaces of the first silicon substrate and the second silicon substrate by etching, respectively. Glass plates that close the grooves are respectively disposed on the surface of the first silicon substrate and the second silicon substrate on the side where the grooves are located; The glass plates are heated to melt and fill the grooves in the first silicon substrate and the second silicon substrate, respectively. The first silicon substrate and the second silicon substrate are thinned on both sides respectively so that the glass plate filled in the groove is exposed at the bottom of the groove and the columnar conductive silicon covered by the glass plate is exposed, so as to obtain the first light-transmitting plate and the second light-transmitting plate. A transparent conductive layer is formed on one side surface of the first light-transmitting plate and the second light-transmitting plate, respectively. The transparent conductive layer on the first light-transmitting plate and the conductive silicon on the first light-transmitting plate are connected to serve as control electrodes on the first light-transmitting plate, and the transparent conductive layer on the second light-transmitting plate and the conductive silicon on the second light-transmitting plate are connected to serve as control electrodes on the second light-transmitting plate.
8. The method for fabricating a multispectral filter as described in claim 6, characterized in that, After providing the first and second light-transmitting plates respectively equipped with control electrodes, the method further includes: Back electrodes are formed on the surfaces of the first and second light-transmitting plates opposite to the Fabry-Perot resonant cavity, respectively. The back electrode on the first light-transmitting plate is connected to the control electrode on the first light-transmitting plate, and the back electrode on the second light-transmitting plate is connected to the control electrode on the second light-transmitting plate.
9. An image acquisition device, characterized in that, Includes the multispectral filter as described in any one of claims 1 to 5.