Spectral imaging chip, device and spectral imaging method

Abstract

The application provides a spectral imaging chip, a spectral imaging device and a spectral imaging method, and relates to the technical field of spectral devices. The spectral imaging chip comprises a light modulation layer, an image sensor layer and a signal processing circuit layer which are sequentially stacked, a plurality of micro-nano structure arrays are distributed on the light modulation layer, and the plurality of micro-nano structure arrays are arranged along a first direction to form a micro-nano structure array group; in the first direction, any one micro-nano structure array is different from other micro-nano structure arrays. The spectral imaging chip, the spectral imaging device and the spectral imaging method provided by the application can realize miniaturization of the spectral imaging device and reduce the cost.

Description

Technical Field

[0001] This invention relates to the field of spectral equipment technology, and in particular to a spectral imaging chip, device, and spectral imaging method. Background Technology

[0002] Spectral imaging technology is a technique that organically combines spectral detection and imaging, enabling the imaging of an object under different spectra, while simultaneously obtaining information about the object's geometric shape and spectral characteristics. Spectral imaging technology has become an important tool for Earth observation and deep space exploration, with a wide range of applications. In the field of astronomy, spectral imaging chip technology, possessing both high spatial resolution and high spectral resolution, can acquire two-dimensional spectral data of sources such as the Milky Way nebula and extragalactic galaxies. This two-dimensional spectral data provides crucial observational evidence for determining the composition of celestial bodies and revealing the formation and evolution of celestial bodies and galaxies.

[0003] In existing technologies, traditional spectral imaging devices, such as integral field-of-view imaging spectrometers, add units such as microlens arrays, fiber bundles, or image splitters in front of the spectrometer to change the spatial distribution of the source image, and then obtain a three-dimensional imaging spectrum through spectrometer dispersion. This approach places high demands on the optical design and fabrication of the front-end units, and the equipment is large, heavy, and expensive. Summary of the Invention

[0004] In order to solve at least one of the technical problems existing in the background art, the present invention provides a spectral imaging chip, device and spectral imaging method, which can realize the miniaturization of spectral imaging device and reduce cost.

[0005] The spectral imaging chip provided by the present invention includes: a light modulation layer, an image sensor layer, and a signal processing circuit layer stacked sequentially. The light modulation layer has multiple micro-nano structure arrays distributed on it, and the multiple micro-nano structure arrays are arranged along a first direction to form a micro-nano structure array group. In the first direction, any one of the micro-nano structure arrays is different from the other micro-nano structure arrays.

[0006] According to one embodiment of the present invention, at least two micro / nano structure array groups are provided along a second direction, the second direction being perpendicular to the first direction.

[0007] According to one embodiment of the present invention, the optical modulation layer includes two stacked distributed Bragg mirror structures and a metasurface layer located between the two distributed Bragg mirror structures.

[0008] According to one embodiment of the present invention, the distributed Bragg reflector structure is a periodic structure composed of alternating silicon nitride layers and silicon dioxide layers, wherein the total number of silicon nitride layers and silicon dioxide layers is at least two.

[0009] According to one embodiment of the present invention, the optical modulation layer includes a plurality of two-dimensional grating structures.

[0010] According to one embodiment of the present invention, the image sensor layer is a CCD or SPAD array.

[0011] According to one embodiment of the present invention, the image sensor layer is a CIS wafer, and the CIS wafer includes a photodetector layer and a metal line layer, the photodetector layer being located below the metal line layer, and the light modulation layer being integrated with the metal line layer.

[0012] According to one embodiment of the present invention, the image sensor layer is a CIS wafer, and the CIS wafer includes a photodetector layer and a metal line layer, the photodetector layer being located above the metal line layer, and the light modulation layer being integrated with the photodetector layer.

[0013] The present invention provides a spectral imaging device, including the spectral imaging chip described above.

[0014] This invention provides a spectral imaging method based on the spectral imaging device described above, comprising: acquiring incident light on the object to be imaged;

[0015] The incident light is optically modulated to obtain at least one modulated spectral information;

[0016] The spectral information is transmitted to the image sensor layer, which converts the spectrum into an electrical signal. The image sensor layer then transmits the electrical signal to the signal processing circuit layer, which converts the electrical signal into a spectral image.

[0017] According to one embodiment of the present invention, the method further includes:

[0018] The spectral imaging device is moved along the first direction to scan the object to be imaged;

[0019] Within a set exposure time, the relative position of the spectral imaging device and the object to be imaged is kept constant by moving the device.

[0020] According to one embodiment of the present invention, the method further includes:

[0021] After a single exposure measurement is completed, a set displacement is generated by moving the spectral imaging chip, causing the entire detected image of the object to be imaged on the image sensor layer to move a set distance of micro-nano structure array, and then the next exposure measurement is performed.

[0022] According to the spectral imaging chip, device, and method provided by the present invention, a micro-nano structure array arranged along a first direction is disposed on the light modulation layer, and the multiple micro-nano structure arrays arranged along the first direction are different from each other. Different micro-nano structure arrays have different filtering effects, that is, different modulation effects on the spectrum of incident light. The object to be imaged is scanned along the first direction, and the light signal corresponding to a certain point of the object is sequentially modulated by different micro-nano structure arrays, converted into an electrical signal by the image sensor layer, and then processed and output by the signal processing circuit layer. Based on the electrical signal detected after a certain point on the object is modulated by all micro-nano structure arrays in the first direction, the spectral information at that point can be obtained. Furthermore, the spectral information of each point on the object to be imaged can be obtained, that is, the spectral image of the object to be imaged. Therefore, by using the spectral imaging chip provided by the present invention to acquire the spectral image of the object to be imaged, the miniaturization of the spectral imaging device can be achieved, reducing costs. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is an exploded structural diagram of the spectral imaging chip provided in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the micro-nano structure array of the photodetector layer of the spectral imaging chip provided in this embodiment of the invention;

[0026] Figure 3 This is a schematic diagram showing the positional relationship between the optical modulation layer and the image sensor layer of the spectral imaging chip provided in this embodiment of the invention;

[0027] Figure 4 This is a schematic diagram of the distributed Bragg reflector and metasurface layer of the optical modulation layer of the spectral imaging chip provided in this embodiment of the invention;

[0028] Figure 5 This is a schematic diagram of the vertical structure of the spectral imaging chip provided in an embodiment of the present invention. Figure 1 ;

[0029] Figure 6 This is a schematic diagram of a two-dimensional grating structure provided in an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the vertical structure of the spectral imaging chip provided in an embodiment of the present invention. Figure 2 ;

[0031] Figure 8 This is a schematic diagram of the image sensor layer provided in an embodiment of the present invention. Figure 1 ;

[0032] Figure 9 This is a schematic diagram of the image sensor layer provided in an embodiment of the present invention. Figure 2 ;

[0033] Figure 10 This is a flowchart of the spectral imaging method provided in an embodiment of the present invention.

[0034] Figure label:

[0035] 1. Spectral imaging chip;

[0036] 10. Optical modulation layer; 11. Micro / nano structure array; 110. Micro / nano structure; 12. Distributed Bragg mirror; 13. Metasurface layer; 14. Two-dimensional grating structure;

[0037] 20. Image sensor layer; 21. Photodetector layer; 22. Metal wire layer;

[0038] 30. Signal processing circuit layer. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0040] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0042] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0043] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0044] In related technologies, traditional spectral imaging equipment has very high requirements for the optical design and processing of the front-end unit, and the equipment is large in size, heavy in weight, and expensive.

[0045] To address the aforementioned problems, this invention provides a spectral imaging chip 1, a device, and a spectral imaging method, which can achieve miniaturization of the spectral imaging device and reduce costs.

[0046] like Figure 1 and Figure 2As shown, the present invention provides a spectral imaging chip 1, which includes a light modulation layer 10, an image sensor layer 20 and a signal processing circuit layer 30 stacked sequentially. Multiple micro-nano structure arrays 11 are distributed on the light modulation layer 10, and the multiple micro-nano structure arrays 11 are arranged along a first direction to form a micro-nano structure array group. In the first direction, any one micro-nano structure array 11 is different from the other micro-nano structure arrays 11.

[0047] The micro / nano structure array 11 on the light modulation layer 10 can modulate the incident light. Different micro / nano structure arrays 11 have different filtering effects, that is, they have different modulation effects on the spectrum of the incident light. This filtering effect can be narrowband filtering or broadband filtering. In the present invention, different micro / nano structure arrays 11 are distributed along the first direction. The incident light at a certain point on the object to be imaged is sequentially modulated by different micro / nano structure arrays 11 along the first direction. The image sensing layer can sense the intensity of the modulated spectrum. For the intensity of the spectrum at different wavelengths, the corresponding image pixel data is determined. That is, the image sensor layer 20 can convert the light signal obtained by the light modulation layer 10 into an electrical signal, and the signal processing circuit layer 30 can receive the electrical signal from the image sensing layer and process the electrical signal into an image.

[0048] The aforementioned micro / nano structure array 11 includes multiple micro / nano structures 110. Each micro / nano structure 110 is the basic unit of the micro / nano structure array 11, which is a two-dimensional periodic arrangement of individual micro / nano structures. Each individual micro / nano structure 110 contains both a dielectric material and micropores. The micro / nano structure array 11 can be a photonic crystal, metasurface, random structure, quantum dots with different absorption spectra, metal SPP micro / nano structures, liquid crystal, FP cavity, two-dimensional materials such as nanodots / nanopillars / nanowires, etc., that have a spectral modulation effect on incident light.

[0049] Each micro / nano structure array 11 has an area of ​​0.5 μm. 2 -40000μm 2 The thickness of the light modulation layer 10 is 10nm-100μm, and each micro-nano structure array 11 corresponds to one or more pixels on the image sensor layer 20. By setting each micro-nano structure array 11 to correspond to one or more pixels on the image sensor layer 20, the image sensor layer 20 can receive the light signal modulated by the micro-nano structure array 11 more accurately, thereby obtaining a more accurate spectral image.

[0050] like Figure 3As shown, the micro / nano structure array 11 in the light modulation layer 10 can be fabricated by directly growing, transferring, bonding, or directly bonding one or more layers of dielectric or metal materials onto the image sensor layer 20, followed by etching or nanoimprinting. This simplifies the manufacturing process of the spectral imaging chip 1, enables miniaturization of the spectral imaging chip 1, reduces device failure rate, improves the stability of the spectral imaging chip 1, and reduces costs. The image sensor layer 20 and the signal processing circuit layer 30 are connected via electrical contacts.

[0051] like Figure 1 and Figure 2 As shown, in some embodiments of the present invention, at least two micro / nano structure array groups are arranged along a second direction, which is perpendicular to the first direction. The micro / nano structure array groups formed by the micro / nano structure arrays 11 arranged in the first direction are sequentially arranged in the second direction, thus distributing multiple micro / nano structure arrays 11 along the second direction. These multiple micro / nano structure arrays 11 arranged along the second direction may be identical or different. In one embodiment of the present invention, the micro / nano structure arrays 11 arranged along the second direction are identical; however, this is not a limitation of the present invention.

[0052] like Figure 4 and Figure 5 As shown, in some embodiments of the present invention, the optical modulation layer 10 includes two stacked distributed Bragg reflector (DBR) structures 12 and a metasurface layer 13 located between the two DBR structures 12. The optical thickness of each DBR structure 12 is 1 / 4 of the center wavelength, corresponding to a range of 10 nm to 100 μm. The DBR structure 12 is a periodic structure composed of alternating arrangements of two materials with different refractive indices. The metasurface layer 13 at different positions has different structural parameters, thus having different equivalent refractive indices, achieving narrowband filtering for different center wavelengths. The metasurface layer 13 can be a silicon nitride pillar metasurface layer 13. The period of the silicon nitride pillar metasurface layer at different positions is 300 nm, and the height of the silicon nitride pillar is 300 nm, but the duty cycle is different, achieving narrowband filtering for different center wavelengths from 500 nm to 700 nm. The center wavelength can be understood as the wavelength with the highest energy (highest transmittance) in the emitted light after passing through a certain region on the optical modulation layer 10. In some embodiments of the present invention, the distributed Bragg reflector 12 has a periodic structure composed of alternating silicon nitride and silicon dioxide layers, with a total of at least two silicon nitride and silicon dioxide layers. For example, in one embodiment of the present invention, the total number of silicon nitride and silicon dioxide layers is 20, and the optical thickness of each silicon nitride layer and each silicon dioxide layer is 150 nm.

[0053] like Figure 6 and Figure 7As shown, in some embodiments of the present invention, the optical modulation layer 10 includes multiple two-dimensional grating structures 14. The two-dimensional grating structures 14 at different locations have different structural parameters such as duty cycle and period, which can achieve different broadband filtering effects.

[0054] In some embodiments of the present invention, the image sensor layer 20 is a CCD or SPAD array. A CCD, or Charge-Coupled Device, is a detection element that uses charge to represent signal magnitude and transmits signals via coupling. It possesses a series of advantages, including self-scanning, a wide sensing spectral range, low distortion, small size, light weight, low system noise, low power consumption, long lifespan, and high reliability, and can be fabricated into a highly integrated assembly. SPAD sensors offer higher sensitivity and accuracy, improving the image sensing performance of the image sensor to obtain higher-quality spectral images.

[0055] like Figure 8 As shown, in some embodiments of the present invention, the image sensor layer 20 is a CIS wafer, and the CIS wafer includes a photodetector layer 21 and a metal line layer 22. The photodetector layer 21 is located below the metal line layer 22, and the light modulation layer 10 is integrated with the metal line layer 22. CIS stands for contact image sensor, which has a simple structure, small size, and convenient application. Specifically, the CIS wafer can be front-illuminated, with the photodetector layer 21 below the metal line layer 22. Microlenses and filters may not be integrated on the wafer, and the light modulation layer 10 is directly integrated onto the metal line layer 22. In this way, the metal line layer 22 can convert optical signal data into electrical signals in advance, speeding up signal processing efficiency and making signal conversion and signal processing more stable and accurate.

[0056] like Figure 9 As shown, in some embodiments of the present invention, the image sensor layer 20 is a CIS wafer, and the CIS wafer includes a photodetector layer 21 and a metal wire layer 22. The photodetector layer 21 is located above the metal wire layer 22, and the light modulation layer 10 is integrated with the photodetector layer 21. After the incident light passes through the light modulation layer 10, it can directly illuminate the photodetector layer 21, which can effectively eliminate the adverse effects of the metal wire layer 22 on the incident light and improve the quantum efficiency of the spectral imaging chip 1.

[0057] This invention provides a spectral imaging device, including the spectral imaging chip 1 as described above. The spectral imaging device can be an astronomical telescope, and the spectral imaging chip 1 is disposed inside the telescope. By scanning, it can achieve high spatial resolution and high spectral resolution spectral imaging of the target celestial object.

[0058] like Figure 10 As shown, the present invention provides a spectral imaging method based on the spectral imaging device described above. The spectral imaging method includes:

[0059] S100: Acquire the incident light of the object to be imaged.

[0060] In some embodiments of the present invention, the spectral imaging method further includes: moving the spectral imaging device along a first direction to scan the object to be imaged; wherein, during a set exposure time, the relative position of the spectral imaging device and the object to be imaged remains unchanged by moving the device.

[0061] In some embodiments of the present invention, the spectral imaging method further includes: after a single exposure measurement is completed, a set displacement is generated by moving the spectral imaging chip 1, so that the detection image of the object to be imaged on the image sensor layer 20 is moved by a set distance of the micro-nano structure array 11, and the next exposure measurement is performed.

[0062] Specifically, when the object to be imaged is in motion, the spectral imaging device needs to be moved to maintain a constant relative position between the device and the object. After a single exposure measurement, the movement of the spectral imaging device needs to be increased so that the detected image of the object on the image sensor layer 20 moves by a predetermined number of micro / nano structure arrays 11. Then, the next exposure measurement is performed, and so on, to obtain the spectral image of the object through multiple exposure measurements. The aforementioned movement direction is the first direction. The predetermined number can be one or more. When the detected image of the object on the image sensor layer 20 moves by one predetermined number of micro / nano structure arrays 11, it is a continuous scanning mode; when the detected image of the object on the image sensor layer 20 moves by multiple predetermined numbers of micro / nano structure arrays 11, it is a discrete scanning mode.

[0063] Alternatively, the spectral imaging chip 1 can be connected to a controllable moving component built into the spectral imaging device. Similarly, during a single exposure within the image sensor layer 20, the relative position of the spectral imaging device and the object to be imaged remains unchanged. After a single exposure measurement is completed, the spectral imaging chip 1 needs to be displaced by the controllable moving component, causing the entire detected image of the object on the image sensor layer 20 to move a distance equal to the size of a micro / nano structure array 11 before the next exposure measurement is performed. This process is repeated to obtain the spectral image of the object through multiple exposure measurements. The aforementioned direction of movement is the first direction.

[0064] S200: Optical modulation of the incident light to obtain at least one modulated spectral information.

[0065] Specifically, the incident light is modulated in the micro-nano structure array 11. During this process, the light modulation layer 10 can be in the form of narrowband filtering or wideband filtering.

[0066] S300, the spectral information is transmitted to the image sensor layer 20 so that the image sensor layer 20 converts the spectrum into an electrical signal, and the image sensor layer 20 transmits the electrical signal to the signal processing circuit layer 30, and the signal processing circuit layer 30 converts the electrical signal into a spectral image.

[0067] In summary, according to the spectral imaging chip 1, device, and spectral imaging method provided by the present invention, by setting a micro / nano structure array 11 arranged along a first direction on the light modulation layer 10, and the multiple micro / nano structure arrays 11 distributed along the first direction are different, the different micro / nano structure arrays 11 have different filtering effects, that is, different modulation effects on the spectrum of incident light. When scanning the object to be imaged along the first direction, the light signal corresponding to a certain point of the object to be imaged is sequentially modulated by different micro / nano structure arrays 11, and converted into an electrical signal by the image sensor layer 20, and then processed and output by the signal processing circuit layer 30. Based on the electrical signal detected after a certain point on the object to be imaged is modulated by all the micro / nano structure arrays 11 in the first direction, the spectral information at that point can be obtained. Furthermore, the spectral information of each point on the object to be imaged can be obtained, that is, the spectral image of the object to be imaged. Therefore, by using the spectral imaging chip 1 to acquire the spectral image of the object to be imaged, the miniaturization of the spectral imaging device can be achieved, reducing costs.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spectral imaging chip, characterized in that, include: A light modulation layer, an image sensor layer, and a signal processing circuit layer are stacked sequentially. Multiple micro-nano structure arrays are distributed on the light modulation layer, and the multiple micro-nano structure arrays are arranged along a first direction to form a micro-nano structure array group. In the first direction, any one of the micro-nano structure arrays is different from the other micro-nano structure arrays; Along a second direction, at least two groups of the micro-nano structure arrays are provided, the second direction being perpendicular to the first direction, and the multiple micro-nano structure arrays arranged along the second direction are different; The optical modulation layer includes two stacked distributed Bragg mirror structures and a metasurface layer located between the two distributed Bragg mirror structures. The metasurface layer at different positions has different equivalent refractive indices to achieve narrowband filtering at different center wavelengths.

2. The spectral imaging chip according to claim 1, characterized in that, The distributed Bragg reflector structure is a periodic structure composed of alternating silicon nitride and silicon dioxide layers, with a total of at least two silicon nitride and silicon dioxide layers.

3. The spectral imaging chip according to claim 1, characterized in that, The optical modulation layer includes multiple two-dimensional grating structures.

4. The spectral imaging chip according to any one of claims 1 to 3, characterized in that, The image sensor layer is a CCD or SPAD array.

5. The spectral imaging chip according to any one of claims 1 to 3, characterized in that, The image sensor layer is a CIS wafer, and the CIS wafer includes a photodetector layer and a metal line layer. The photodetector layer is located below the metal line layer, and the light modulation layer is integrated with the metal line layer.

6. The spectral imaging chip according to any one of claims 1 to 3, characterized in that, The image sensor layer is a CIS wafer, and the CIS wafer includes a photodetector layer and a metal line layer. The photodetector layer is located above the metal line layer, and the light modulation layer is integrated with the photodetector layer.

7. A spectral imaging device, characterized in that, Includes the spectral imaging chip according to any one of claims 1-6.

8. A spectral imaging method based on the spectral imaging device of claim 7, characterized in that, The method includes: Acquire the incident light of the object to be imaged; modulate the incident light to obtain at least one modulated spectral information; The spectral information is transmitted to the image sensor layer, which converts the spectrum into an electrical signal. The image sensor layer then transmits the electrical signal to the signal processing circuit layer, which converts the electrical signal into a spectral image.

9. The spectral imaging method according to claim 8, characterized in that, The method further includes: The spectral imaging device is moved along the first direction to scan the object to be imaged; Within a set exposure time, the relative position of the spectral imaging device and the object to be imaged is kept constant by moving the device.

10. The spectral imaging method according to claim 9, characterized in that, The method further includes: After a single exposure measurement is completed, a set displacement is generated by moving the spectral imaging chip, causing the entire detected image of the object to be imaged on the image sensor layer to move a set distance of micro-nano structure array, and then the next exposure measurement is performed.

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