WO2021237567A1

WO2021237567A1 - Tunable optical filter device and spectral imaging system

Info

Publication number: WO2021237567A1
Application number: PCT/CN2020/092910
Authority: WO
Inventors: 郭斌
Original assignee: 深圳市海谱纳米光学科技有限公司
Priority date: 2020-05-28
Filing date: 2020-05-28
Publication date: 2021-12-02
Also published as: CN113767309A

Abstract

A tunable optical filter device, comprising a first substrate (104, 201) having a first reflection structure and a second substrate (108, 207) having a second reflection structure. The surface peripheries having the reflection structures of the first substrate (104, 201) and the second substrate (108, 207) are bonded to each other by means of a bonding compound (106, 205) to form a cavity between the reflection structures, and optical material blocks (109, 209) of different thicknesses are distributed on the surface having the reflection structure of the first substrate (104, 201) and/or the second substrate (108, 207) in the cavity. A spectral imaging system, comprising a tunable optical filter device, and further comprising an imaging chip (402). The tunable optical filter device and the imaging chip (402) are bonded to each other. Another spectral imaging system, comprising a tunable optical filter device. one of a first substrate (104, 201) and a second substrate (108, 207) of the tunable optical filter device is an imaging chip (402).

Description

Adjustable optical filter device and spectral imaging system

Technical field

The invention relates to the field of semiconductor devices, and in particular to a tunable optical filter device and a spectral imaging system.

Background technique

Hyperspectral imaging in visible light-near infrared (e.g. 400-1000nm), near-infrared-shortwave infrared (e.g. 900nm-2500nm) and mid-to-far infrared (e.g. 3-14 microns) is sometimes used for real-time target recognition, semantic segmentation and semantic recognition And other applications. These applications often require real-time acquisition of images, that is, a relatively high image refresh rate (frame rate) of hyperspectral image data is required.

The solution based on traditional prism beam splitting requires mechanical scanning to realize two-dimensional space imaging, so it is not suitable for high frame rate applications. The solution based on the wheel requires a mechanical wheel to realize that a specific filter covers the imaging chip at a certain time, and the result is an increase in volume and a decrease in stability. Although the solution based on prism and lens matrix can achieve higher frame rate imaging at the sacrifice of spatial resolution, it greatly increases the complexity and cost of the system.

Tunable filter devices (FPI) based on Fabry-Perot interference can be used to manufacture miniature spectrometers and miniature or even miniature hyperspectral cameras. The Faber cavity device can provide the most compact structure and the most concise optical path design in the aforementioned visible light-near-infrared-shortwave infrared and mid-to-far infrared range. The traditional adjustable Faber cavity adopts a time-sharing imaging method similar to a mechanical wheel, in which only one band of light is gated into the imaging chip at a certain time.

Summary of the invention

In order to solve the problem that the tunable Faber cavity in the prior art has only one wavelength band of light energy being gated into the imaging chip at a certain time, the present invention proposes a tunable optical filter to try to solve the existing tunable The problem that the filter device cannot gate light of different wavelength bands to different positions of the imaging chip at the same time.

The present invention provides a tunable optical filter device. The device includes a first substrate provided with a first reflective structure and a second substrate provided with a second reflective structure. The first substrate and the second substrate have a reflective structure. The surface peripheries of the structures are bonded to each other through the bonding compound to form a cavity between the reflective structures, and the surfaces of the first substrate and/or the second substrate with the reflective structure in the cavity are distributed with optical material blocks of different thicknesses. By virtue of the optical material blocks of different thicknesses distributed in the cavity, the Faber cavity can simultaneously select light of different wavelength bands to be incident on corresponding different positions.

Preferably, the optical material block is made of semiconductor material or insulator material. Choose semiconductor or insulator material as the medium that can transmit light in the infrared spectral range, and use its different thickness and different spatial position to obtain the spectral response of different wavelengths.

Further preferably, the optical material block is formed by processing on a substrate, and a reflective structure is deposited on the surface of the substrate and the optical material block. The process of processing the optical material block on the substrate in advance by etching or the like before deposition is relatively simple and easy to implement.

Further preferably, the optical material block is processed and formed on the reflective structure, and the reflective structure is a thin film material deposited on the substrate. By processing the optical material block on the deposited reflective structure, the thickness of the optical material block can be better controlled, so that the overall filter characteristics are more accurate.

Further preferably, the optical material blocks of different thicknesses form an array structure on the surface of the first substrate and/or the second substrate with a reflective structure. The array structure is similar to a mosaic pattern, and a single mosaic corresponds to the length of a specific resonant cavity, which in turn corresponds to a specific gate wavelength.

Further preferably, multiple groups of array structures are arranged according to the thickness of different optical material blocks to form a pixel matrix. The composed pixel matrix can provide multiple combinations of different wavelengths to form a corresponding hyperspectral image.

Further preferably, the thickest optical material block in the cavity abuts the first reflective structure and the second reflective structure at the same time. The optical material block simultaneously abuts the Faber cavities of the two reflective structures to form a fixed Faber cavity structure.

Further preferably, individual regions in the array structure do not have optical material blocks. The area without the optical material block is the original Faber cavity without the optical material block.

Preferably, the first reflective structure and the second reflective structure are Bragg reflectors. Setting the reflective structure as a Bragg reflector can reduce reflection within a certain wavelength range and increase the amount of light passing.

Further preferably, the optical material block with the largest thickness in the optical material block does not abut the reflective structure of another substrate facing it, and the first substrate and/or the second substrate are provided with a first substrate for controlling A drive device for the relative displacement of the bottom and/or the second substrate. The drive device includes a first electrode disposed between the first reflective structure and the bond, and a second reflective structure opposite to the first electrode in the cavity. electrode. By virtue of the capacitor structure formed between the first electrode and the second electrode, the relative displacement of the first substrate and/or the second substrate can be driven.

Preferably, the first reflective structure and the second reflective structure are mirror surfaces, and the material of the mirror surfaces includes silicon, silicon oxide or a combination thereof, or silver. The diversification of mirror materials can be selected according to actual needs.

Further preferably, the optical material block with the largest thickness in the optical material block does not abut the reflective structure of another substrate facing it, and the first substrate and/or the second substrate are provided with a first substrate for controlling A drive device for the relative displacement of the bottom and/or the second substrate. The drive device includes a third electrode located on the surface of the peripheral silicon layer on the surface of the first substrate opposite to the mirror surface and a third electrode located on the mirror surface opposite to the third electrode The fourth electrode. By virtue of the capacitance structure formed between the third electrode and the fourth electrode, the relative displacement of the first substrate and/or the second substrate can be driven.

Preferably, a ring-shaped weight formed of silicon is provided in the middle of the surface of the first substrate and/or the second substrate opposite to the cavity. With the setting of the ring-shaped weight, the flatness of the substrate can be improved when working.

Preferably, the manner in which the surface periphery of the first substrate and the second substrate having the reflective structure are bonded to each other through a bonding compound includes eutectic bonding, polymer bonding, or anodic bonding. By means of bonding, the two glass film structures can be tightly combined to ensure the stability of the tunable optical filter.

According to the second aspect of the present invention, a spectral imaging system is provided, which includes the above-mentioned tunable optical filter component, and also includes an imaging chip, and the tunable optical filter component and the imaging chip are mutually bonded. By virtue of the cooperation of the tunable optical filter and the imaging chip, it is possible to simultaneously gate light of different wavelength bands to be incident on the corresponding different positions of the imaging chip, and realize imaging with a higher frame rate.

According to a third aspect of the present invention, a spectral imaging system is provided, including the above-mentioned tunable optical filter device, and one of the first substrate and the second substrate of the tunable optical filter device is an imaging chip. By using one of the substrates as the imaging chip, it is possible to simultaneously gate light of different wavelength bands to be incident on the corresponding different positions of the imaging chip, and realize imaging with a higher frame rate.

Preferably, the imaging chip includes a silicon-based device in the visible-near-infrared range, an indium gallium arsenide detector in the near-infrared-short-wave infrared range, a detector in the mid-to-far infrared range, a thermopile or a microbolometer.

The tunable optical filter device of the present invention retains the advantages of the compact structure and simple optical path of the Faber cavity. By distributing the optical material blocks of different thicknesses in the two-dimensional space of the Faber cavity, different resonances are formed in the Faber cavity The length of the cavity realizes the pattern of the array mosaic structure, and a single mosaic can correspond to a specific resonant cavity length, and then to a specific gate wavelength. A spectral imaging system is also proposed, which can make a single mosaic correspond to a single or several imaging units of the imaging chip by bonding the tunable filter to the imaging chip or directly using one of the substrates of the tunable filter as the imaging chip. , And then form a hyperspectral image.

Description of the drawings

The drawings are included to provide a further understanding of the embodiments and the drawings are incorporated into this specification and constitute a part of this specification. The drawings illustrate the embodiments and together with the description serve to explain the principles of the present invention. It will be easy to recognize the other embodiments and the many expected advantages of the embodiments because they become better understood by quoting the following detailed description. The elements of the drawings are not necessarily in proportion to each other. The same reference numerals refer to corresponding similar components.

Figure 1 is a cross-sectional view of a visible-near-infrared tunable optical filter device according to a first embodiment of the present invention;

2 is a cross-sectional view of a mid-to-far infrared tunable optical filter device according to a second embodiment of the present invention;

FIG. 3 is a diagram of simulation results of far infrared spectra of a tunable optical filter device according to a specific embodiment of the present invention;

Fig. 4 is a cross-sectional view of a spectral imaging system according to an embodiment of the present invention.

Detailed ways

In the following detailed description, reference is made to the accompanying drawings, which form a part of the detailed description and are shown through illustrative specific embodiments in which the present invention can be practiced. In this regard, directional terms such as "top", "bottom", "left", "right", "upper", "lower", etc. are used with reference to the orientation of the described figure. Because the components of an embodiment can be positioned in several different orientations, directional terms are used for illustration purposes and directional terms are by no means limiting. It should be understood that other embodiments may be utilized or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description should not be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

Fig. 1 shows a cross-sectional view of a visible-near-infrared tunable optical filter device according to a first embodiment of the present invention. As shown in FIG. 1, the tunable optical filter device includes a first substrate 104 and a second substrate 108, wherein the first substrate 104 is configured as a displaceable substrate structure, and the second substrate 108 is configured as a fixed substrate. The substrate structure. The first substrate 104 and the surface silicon layer 103 are tightly combined by bonding. The optical mirror 105 and the optical mirror 107 are respectively deposited on the first substrate 104 and the second substrate 108 by micromachining and etched into corresponding patterns. The first substrate 104 and the second substrate 108 are mirrored. The outer periphery of one side of the silicon layer is bonded to each other through the first bonding compound 106 to form a Fabry-Perot cavity. A first electrode 102 is provided on the outer surface of the surface silicon layer 103. The optical mirror 105 can be used as a second electrode. The electrode 102 and the optical mirror 105 can form a driving capacitor for driving the displacement of the first substrate 104. The driving capacitor drives the displacement of the first substrate 104 to adjust the gap of the Fabry-Perot cavity to realize the function of adjustable optical filtering. The processing cost is low and the processing technology is simpler, and it can be applied to devices with limited space size such as mobile phones.

In a preferred embodiment, after the first substrate 104 and the second substrate 108 are bonded, the optical mirror 105 and the optical mirror 107 are parallel to each other and form a reflection zone in the Fabry-Perot cavity. The material of the mirror surface 107 is a metal mirror surface, and the material can be silver or other metals. The mirror surface structure of the metal material can form a driving capacitor for driving the displacement of the first substrate 104 through the surface silicon layer 103 with good conductivity and the first electrode 102. The selectivity of the mirror surface material can be selected as the electrode according to actual needs. It can also be used as an electrode by appropriately doping a silicon film to achieve a certain degree of conductivity. The first electrode 102 is arranged on the outer surface of the surface silicon layer 103 It can facilitate the later package connection of the device.

In a specific embodiment, the optical material blocks 109 of different thicknesses are distributed in the Fabry-Perot cavity, and the optical material blocks 109 of different thicknesses form different resonant cavity lengths in the two-dimensional space of the Faber cavity. Can be strobed to correspond to a specific wavelength. The optical material block 109 is made of a thin film that can transmit light in the visible-near-infrared spectrum, such as a semiconductor material or an insulator material, and uses a semiconductor or insulator material as a medium that can transmit light in the infrared spectrum, and uses its different thickness and different spatial positions. Obtain the spectral response of different wavelengths.

In a specific embodiment, the optical material block 109 may be formed by processing on a substrate, and an optical mirror 105 is deposited on the substrate and the surface of the optical material block 109. The process of processing the optical material block 109 on the substrate in advance by etching or the like before deposition is relatively simple and easy to implement. In other embodiments, the optical material block 109 may also be processed and formed on the optical mirror 105, which is a thin film material deposited on the substrate. By processing the optical material block 109 on the deposited optical mirror surface 105, the thickness of the optical material block 109 can be better controlled, so that the overall filter characteristics are more accurate.

In a preferred embodiment, the optical material blocks 109 of different thicknesses form an array structure on the surface of the first substrate 104 with a reflective structure. The array structure is similar to a mosaic pattern, and a single mosaic corresponds to the length of a specific resonant cavity. Corresponds to a specific strobe wavelength. Further preferably, multiple groups of array structures are arranged according to the thickness of different optical material blocks 109 to form a pixel matrix, and the formed pixel matrix can provide multiple combinations of different wavelengths to form a hyperspectral image correspondingly.

Although FIG. 1 shows that the optical material blocks 109 are arranged as optical material blocks 1091-1094 of different thicknesses to form a 4*4 pixel pattern, it should be realized that other combination patterns such as 2*2, 3* can also be used. 3, 5*5 and other styles to form an effective pixel, and the pixel can provide 4, 9, 16 or 25 combinations of different wavelengths. The pixel can be used for matrix distribution to form a hyperspectral image correspondingly. The spatial resolution of the image is determined by the size of the pixels.

In a specific embodiment, the thickest optical material block 109 in the Farber cavity can abut the optical mirror surface 105 and the optical mirror surface 107 at the same time. At this time, the Farber cavity has a fixed Farber cavity structure, and there is no need to provide a second cavity structure. One electrode 102. If an adjustable Farber cavity structure is required, the optical material block with the largest thickness in the optical material block 109 does not abut the optical mirror surface of the other substrate it faces, and the first substrate 104 and/or the second substrate A driving device for controlling the relative displacement of the first substrate 104 and/or the second substrate 108 is provided on the 108, that is, a driving capacitor formed by the first electrode 102 and the second electrode. Individual areas in the array structure do not have optical material blocks 109, and the optical medium in this area is air, that is, the Faber cavity without optical material blocks originally. The Faber cavity can be set as a fixed or adjustable Faber cavity structure according to actual application requirements, and the corresponding function can be realized by setting the thickness of the optical material block 109.

In a preferred embodiment, a plasma etching method is used to partially remove the surface silicon layer 103 on the first substrate 104 to form a ring-shaped weight 101 for enhancing the flatness of the first substrate 104. It should be recognized that The shape of the ring weight 101 is not limited to a circle, but can also be other regular or irregular shapes such as an ellipse and a rectangle. The etching method is not limited to plasma etching, and it can also be etching with chemical reagents. Choose the appropriate one according to the specific application scenario. The etching method etches the required shape.

In a specific embodiment, the bonding method between the first substrate 104 and the second substrate 108 may specifically be eutectic bonding, polymer or anodic bonding. Eutectic bonding is the use of metal as the transition layer to achieve the bonding between silicon and silicon. The surface requirements are not high, the bonding temperature is low, and the bonding strength is high; anodic bonding has a low bonding temperature, which is comparable to other processes. It has the advantages of good capacitance, high bonding strength and stability, and can be used for bonding between silicon and silicon substrates, non-silicon materials and silicon materials, and mutual bonding between glass, metal, semiconductor, and ceramics. A suitable bonding method can be selected for the actual bonding surface process and material to achieve bonding between the two substrates.

Fig. 2 shows a cross-sectional view of a mid- and far-infrared tunable optical filter device according to a second specific embodiment of the present invention. As shown in FIG. 2, the tunable optical filter device includes a first substrate 201 and a second substrate 207. One side of the first substrate 201 is provided with a first Bragg reflector 203, and one side of the second substrate 207 The surface is provided with a second Bragg reflector 206, the second substrate 207 and the second Bragg reflector 206 have a larger epitaxy than the first substrate 201 and the first Bragg reflector 203, the first Bragg reflector 203 and the second Bragg reflector 203 The outer periphery of the surface of the Bragg reflector 206 is bonded to each other through the second bonding compound 205 to form a Fabry-Perot cavity between the two Bragg reflectors, and a Fabry-Perot cavity is formed between the first Bragg reflector 203 and the bonding compound 5. The third electrode 2041 and the second Bragg reflector 206 are provided with a fourth electrode 2042 at a position corresponding to the third electrode 2041 in the Fabry-Perot cavity, which is formed between the third electrode 2041 and the fourth electrode 2042 The capacitive drive structure can make the first Bragg reflector 203 and the second Bragg reflector 206 generate a relative displacement to adjust the gap of the Fabry-Perot cavity to realize the function of adjustable optical filtering. The first substrate 201 and the second substrate The middle part of 207 is removed to form an incident area through which light can pass.

In a preferred embodiment, the first Bragg reflector 203 is formed by a silicon oxide layer 2031, a peripheral silicon layer 2032, a third bond 2033, and a peripheral silicon layer 2034 on the first substrate 201 by semiconductor processing. The two Bragg reflectors 206 are formed by the alternating silicon layer 2061, the fourth bond 2062, the silicon layer 2063 and the silicon oxide layer 2064 on the second substrate 207 through semiconductor processing, wherein the peripheral silicon layers 2032 and 2034 pass The third bonding compound 2033 is bonded to each other, and the silicon layer 2061 and the silicon layer 2063 are bonded to each other through the fourth bonding compound 2062. By virtue of the Bragg reflector structure provided on the first substrate 201 and the second substrate 207, light will be reflected and refracted correspondingly when passing through the silicon oxide and silicon layers. With a reasonable configuration, the light can have different refractive indexes. The film layers are reflected, and the reflected light interferes constructively due to the change of the phase angle, and then combines with each other to obtain strong reflected light, which can reduce the reflection of the light within a certain wavelength range and increase the amount of light passing.

In a preferred embodiment, after the first Bragg reflector 203 and the second Bragg reflector 206 are bonded to each other through the second bonding compound 205, the first Bragg reflector 203 and the second Bragg reflector 206 are parallel to each other and in the method. A reflection zone is formed in the Brie-Perot cavity. The third electrode 2041 and the fourth electrode 2042 are metal electrodes, which are processed on the surfaces of the first Bragg reflector 203 and the second Bragg reflector 206 by a semiconductor processing technology. The third electrode 2041 and the fourth electrode 2042 at the opposite position constitute a driving capacitor. The fourth electrode 2042 is partially disposed on the lateral extension of the second Bragg reflector 203, which can provide convenience for external electrode leads and facilitate subsequent packaging.

In a specific embodiment, the optical material blocks 209 of different thicknesses are distributed in the Fabry-Perot cavity, and the optical material blocks 209 of different thicknesses form different resonant cavity lengths in the two-dimensional space of the Faber cavity. Can be strobed to correspond to a specific wavelength. The optical material block 209 is made of a thin film that can transmit light in the infrared spectral range, such as a semiconductor material or an insulator material. The semiconductor or insulator material is selected as a medium that can transmit light in the infrared spectral range, and its different thickness and different spatial positions can be used to obtain different Spectral response of wavelength.

In a specific embodiment, the optical material block 209 may be formed by processing on a substrate, and a Bragg reflector is deposited on the surface of the substrate and the optical material block. The process of processing the optical material block 209 on the substrate in advance by etching or the like before deposition is relatively simple and easy to implement. In other embodiments, the optical material block 209 can also be formed by processing on a Bragg reflector, which is a thin film material deposited on a substrate. By processing the optical material block 209 on the deposited Bragg reflector, the thickness of the optical material block 209 can be better controlled, so that the overall filter characteristics are more accurate.

In a preferred embodiment, the optical material blocks 209 of different thicknesses form an array structure on the surface of the first Bragg reflector 203. The array structure is similar to a mosaic pattern, and a single mosaic corresponds to a specific resonant cavity length, which in turn corresponds to a specific resonant cavity. The strobe wavelength. Further preferably, multiple groups of array structures are arranged according to the thickness of different optical material blocks to form a pixel matrix, and the formed pixel matrix can provide a combination of multiple different wavelengths to form a hyperspectral image correspondingly.

Although FIG. 2 shows that the optical material blocks 209 are set as optical material blocks 2091-2094 of different thicknesses to form a 4*4 pixel pattern, it should be realized that other combination patterns such as 2*2, 3* can also be used. 3, 5*5 and other styles to form an effective pixel, and the pixel can provide 4, 9, 16 or 25 combinations of different wavelengths. The pixel can be used for matrix distribution to form a hyperspectral image correspondingly. The spatial resolution of the image is determined by the size of the pixels.

In a specific embodiment, the thickest optical material block in the Faber cavity can abut the first Bragg reflector 203 and the second Bragg reflector 206 at the same time. At this time, the Faber cavity has a fixed Farber cavity structure. , The driving electrode 204 may not need to be provided. If it is necessary to use a tunable Faber cavity structure, the optical material block with the largest thickness in the optical material block 209 fails to abut the Bragg reflector of the other substrate it faces, and the first Bragg reflector 203 and the second Bragg reflector The Bragg reflector 206 is provided with a driving capacitor device for controlling the relative displacement of the first Bragg reflector 203 and/or the second Bragg reflector 206, that is, a driving capacitor formed by the third electrode 2041 and the fourth electrode 2042. Individual areas in the array structure do not have optical material blocks 209, and the optical medium in this area is air, that is, the Faber cavity without optical material blocks originally. The Faber cavity can be set as a fixed or adjustable Faber cavity structure according to actual application requirements, and corresponding functions can be realized by setting the thickness of the optical material block 209.

The first substrate 201 and the second substrate 207 are removed to form the ring-shaped

weight structures

202, 208 and the supporting structure. It should be realized that the shape of the ring-shaped

weights

202, 208 is not limited to a circle, and may also be an ellipse, a rectangle, etc. For regular or irregular shapes, the removal method can be plasma etching or chemical reagent etching. The appropriate etching method is selected to etch the required shape according to the specific use scene.

In a specific embodiment, the bonding method between the first Bragg reflector 203 and the second Bragg reflector 206 may specifically be eutectic bonding, polymer or anodic bonding. Eutectic bonding is the use of metal as the transition layer to achieve the bonding between silicon and silicon. The surface requirements are not high, the bonding temperature is low, and the bonding strength is high; anodic bonding has a low bonding temperature, which is comparable to other processes. It has the advantages of good capacitance, high bonding strength and stability, and can be used for bonding between silicon and silicon substrates, non-silicon materials and silicon materials, and mutual bonding between glass, metal, semiconductor, and ceramics. A suitable bonding method can be selected for the actual bonding surface technology and material to achieve the bonding between the two glass films.

Continuing to refer to FIG. 3, FIG. 3 shows a simulation result diagram of the far-infrared spectrum of the tunable optical filter device according to a specific embodiment of the present invention. As shown in FIG. 3, when the optical material block (OM) has different thicknesses, Corresponding to different wavelength positions on the spectrum, in the same reflective structure and Faber cavity structure, only by changing the thickness of air and optical material (OM), the spectrum corresponding to different wavelengths can be obtained at different spatial positions. It should be noted that a single The position of the optical material, that is, the wave crest corresponding to a single mosaic position may be greater than one. The optical material (OM) can be an insulating material (such as an oxide), a semiconductor material, or an organic film that can transmit light in the infrared spectrum.

Continuing to refer to FIG. 4, FIG. 4 is a cross-sectional view of a spectral imaging system according to an embodiment of the present invention. As shown in FIG. 4, the spectral imaging system includes the adjustable optical filter as shown in FIG. 1, and also includes an imaging chip 402. The imaging chip 402 and the tunable optical filter shown in FIG. 1 are bonded to each other through a bonding compound 401 to form a spectral imaging system. FIG. 4 only shows a spectral imaging system formed by bonding the tunable optical filter device shown in FIG. 1 and the imaging chip 402, but it should be realized that the tunable optical filter device and imaging device shown in FIG. The chip 402 is bonded to form a spectral imaging system, which can also achieve the technical effects of the present invention.

In another embodiment, one of the substrates of the tunable optical filter device shown in FIG. 1 or FIG. 2 can be used as the imaging chip itself, that is, the aforementioned tunable optical filter is manufactured on the basis of the imaging chip itself as the substrate. The device can also achieve the technical effects of the spectral imaging system of the present invention.

In a preferred embodiment, the imaging chip 402 includes silicon-based devices such as CCD and CMOS in the visible light-near infrared range (such as 400-1000nm), indium gallium arsenide detectors in the near-infrared-shortwave infrared range (900-2500nm), Other compound detectors, thermopiles or microbolometers in the mid-to-far infrared range (such as 3-14 microns).

The tunable optical filter of the present invention uses metal (such as silver, etc.) or Bragg reflector DBR (such as semiconductor/insulating layer, or semiconductor/air layer) wide mirror surface to form a Faber cavity structure, which is formed by optical materials of different thicknesses The length of the cavity with a mosaic distribution of Farber cavity (the effective optical distance between the two mirrors of the Farber cavity), each cavity length corresponds to a specific Farber cavity spectral response, and within a certain spectral range, the spectral response One or more wave crests can appear, and different resonant cavity lengths can be realized by processing areas of different heights on the mirror wafer substrate, that is, by etching and other methods before the mirror film deposition; After the mirror film is deposited, optical film materials with different heights in different areas are processed on the mirror film. According to the arrangement of the above-mentioned adjustable optical filter and imaging chip, a spectral imaging system is proposed. The Farber cavity structure with the length of the mosaic distributed resonant cavity can be directly fabricated on the imaging chip as a thin film, that is, the substrate of the Farber cavity is The imaging chip itself; the Farber cavity structure with the length of the mosaic distributed resonant cavity can also be used as an independent chip, which is assembled with the imaging chip by bonding and other methods to form a spectral imaging system. The hyperspectral imaging system composed of the mosaic adjustable Farber cavity can simultaneously gate light of different wavelength bands to be incident on the corresponding different positions of the imaging chip, thereby realizing imaging with a higher frame rate.

Obviously, those skilled in the art can make various modifications and changes to the embodiments of the present invention without departing from the spirit and scope of the present invention. In this way, if these modifications and changes are within the scope of the claims of the present invention and their equivalents, the present invention is also intended to cover these modifications and changes. The word "comprising" does not exclude the presence of other elements or steps not listed in a claim. The simple fact that certain measures are recorded in mutually different dependent claims does not indicate that the combination of these measures cannot be used for profit. Any reference signs in the claims should not be considered as limiting the scope.

Claims

A tunable optical filter device, wherein the device includes a first substrate provided with a first reflective structure and a second substrate provided with a second reflective structure, the first substrate and the second substrate The surface peripheries of the two substrates with reflective structures are bonded to each other through a bonding compound to form a cavity between the reflective structures, and the first substrate and/or the second substrate in the cavity has a reflective structure. Optical material blocks of different thicknesses are distributed on the surface of the structure.
The tunable optical filter device according to claim 1, wherein the optical material block is made of semiconductor material or insulator material.
The tunable optical filter device according to claim 1 or 2, wherein the optical material block is formed by processing on the substrate, and the substrate and the surface of the optical material block are deposited The reflective structure.
The tunable optical filter device according to claim 1 or 2, wherein the optical material block is processed and formed on the reflective structure, and the reflective structure is a thin film material deposited on the substrate.
The tunable optical filter device according to claim 1 or 2, wherein the optical materials of different thicknesses form an array on the surface of the first substrate and/or the second substrate with a reflective structure. structure.
The tunable optical filter device according to claim 5, wherein multiple groups of the array structure are arranged according to the thickness of the different optical material blocks to form a pixel matrix.
The tunable optical filter device according to claim 4, wherein the thickest optical material block in the cavity abuts the first reflective structure and the second reflective structure at the same time.
The tunable optical filter device according to claim 5, wherein individual regions in the array structure do not have the optical material block.
The tunable optical filter device according to claim 1, wherein the first reflective structure and the second reflective structure are Bragg reflectors.
The tunable optical filter device according to claim 9, wherein the optical material block with the largest thickness in the optical material block does not abut against the reflective structure of another substrate that it faces, and the first A drive device for controlling the relative displacement of the first substrate and/or the second substrate is provided on the substrate and/or the second substrate, and the drive device includes a drive device provided on the first reflective structure The first electrode between the bonding compound and the second electrode of the second reflective structure opposite to the first electrode in the cavity.
The tunable optical filter device according to claim 1, wherein the first reflective structure and the second reflective structure are mirror surfaces, and the material of the mirror surfaces includes silicon, silicon oxide or a combination thereof, or silver.
The tunable optical filter device according to claim 11, wherein the optical material block with the largest thickness in the optical material block does not abut against the reflective structure of another substrate that it faces, and the first The substrate and/or the second substrate are provided with a driving device for controlling the relative displacement of the first substrate and/or the second substrate, and the driving device includes a driving device located on the first substrate and A third electrode on the surface of the peripheral silicon layer on the surface opposite to the mirror surface and a fourth electrode on the mirror surface opposite to the third electrode.
The tunable optical filter device according to claim 1, wherein the center of the surface of the first substrate and/or the second substrate opposite to the cavity is provided with a ring-shaped weight formed by silicon. Things.
The tunable optical filter device according to claim 1, wherein the surface periphery of the first substrate and the second substrate having a reflective structure are bonded to each other through a bonding compound including eutectic bonding , Polymer or anodic bonding.
A spectral imaging system, characterized by comprising the tunable optical filter device according to any one of claims 1-14, and further comprising an imaging chip, and the tunable optical filter device and the imaging chip are mutually bonded .
A spectral imaging system, characterized in that it comprises the tunable optical filter device according to any one of claims 1-14, and the first substrate and the second substrate of the tunable optical filter device are One is an imaging chip.
The spectral imaging system according to claim 15 or 16, wherein the imaging chip includes a silicon-based device in the visible-near infrared range, an indium gallium arsenide detector in the near-infrared-shortwave infrared range, and mid-far infrared Range of detectors, thermopile or microbolometer.