Method for improving resolution of a spectral analysis module based on a filter array

Abstract

The application provides a method for improving the resolution of a spectral analysis module based on a filter array with metal micro-nano structures, and mainly relates to the layout planning of the structural parameter variables of each filter unit in the filter array, wherein all the filter units are divided into several filter unit groups, the variation step of the characteristic wavelength in the transmission spectrum of different filter units in the filter array is finely controlled by adjusting the longitudinal structural parameters of the filter units between different filter unit groups. The method provided by the application makes the process of adjusting the longitudinal structural parameters of the filter units simple and controllable, and overcomes the resolution restriction of the spectral analysis module caused by the insufficient control accuracy of the transverse structural parameter variables of the filter units due to the limited micro-nano processing precision.

Description

Technical Field

[0001] This invention relates to a spectral analysis module based on a filter array, and more particularly to a method for improving the resolution of such a spectral analysis module. Background Technology

[0002] A spectrometer is a very important optical instrument. Currently, common spectrometers can be broadly categorized into two types: one is the dispersive type, represented by grating spectrometers; the other is the modulation type, represented by Fourier transform spectrometers based on interferometers. Laboratory-grade professional spectrometers are generally large and expensive, and their overall performance often decreases as the instrument size decreases.

[0003] In recent years, with the development of information technology, the intelligentization of production and life, and the increasing demand for food safety, environmental pollution, and medical health, miniature integrated spectral analysis modules have attracted attention. Their application is increasingly focused on serving as sensing components in intelligent devices and consumer electronics products (such as smartphones and wearable devices).

[0004] Among them, micro-spectral analysis modules based on filter arrays have attracted widespread attention. This type of spectral analysis module uses the transmitted light from filter structural units with different transmission spectral characteristics in the filter array to illuminate the corresponding detector units in the detector array for photoelectric conversion, and then performs spectral reconstruction through back-end data processing.

[0005] Common filter array structures used in spectral analysis modules include: vertical Fabry-Perot resonant cavity array structures with different cavity lengths; filter array structures based on metal micro / nano structures; filter array structures based on photonic crystal structures of dielectric materials; and array structures based on semiconductor quantum dots or quantum wires with different absorption spectra; etc.

[0006] With the rise and rapid development of micro-nano optics and plasmonic optics in recent years, the application of filter arrays based on metal micro-nano structures in the development of novel spectral analysis modules has received particular attention [as involved in the following published invention patents: Chinese invention patents CN 105092035B, CN 109642822A, CN 108731806 A, CN 110873911 A, CN110243471 A, CN 10954311 A, CN109564323 A, etc.; US invention patents US 8542359 B2, US7426040 B2, etc.]. Because light waves can be coupled to plasmonic optical modes in metal micro-nano structures, the propagation and resonance of light waves can be controlled at the subwavelength scale, giving the transmission spectrum of such metal micro-nano structures filtering characteristics.

[0007] For filter arrays based on metal micro / nano structures, each filter unit typically possesses different structural parameters, resulting in varying transmission spectral characteristics (i.e., filtering properties). The spectral resolution of a filter array-based spectral analysis module heavily depends on the step size of the characteristic wavelength variation in the transmission spectra of different filter units within the array; moreover, this hardware-level dependence is fundamental and decisive. Therefore, the fabrication precision of the micro / nano fabrication equipment used to prepare the metal micro / nano structures largely determines the spectral resolution of the filter array-based spectral analysis module.

[0008] For example, the relationship between the step size (denoted as Δx) of the structural dimensions of the metal micro / nano structure in the lateral direction (i.e., within the substrate plane) of different filter units in a filter array based on metal micro / nano structures and the step size (Δλ) of the characteristic wavelength in its transmission spectrum is generally approximated as Δλ≈nΔx, where n is slightly larger than the optical refractive index of the medium adjacent to the metal micro / nano structure (e.g., the optical refractive index of silicon dioxide is about 1.5).

[0009] Currently, the processing equipment used to fabricate the metal micro / nano structures in the filter array (such as ultraviolet lithography, nanoimprinting, electron beam lithography, and plasma etching equipment) can only achieve a process precision of approximately Δx = 10–20 nm. Such process precision makes it difficult for the spectral analysis module to achieve a sufficiently high spectral resolution (such as Δλ < 5 nm) to meet the needs of many different applications.

[0010] Although the precision of existing micro-nano fabrication processes is still relatively limited, the control precision of thin film thickness in optical coating processes is relatively high (e.g., Δz < 5 nm or even smaller). Moreover, the step size (Δλ) of the characteristic wavelength variation in the transmission spectrum of the filter unit is generally much smaller than the step size (Δz) of the thickness variation of the dielectric thin film layer adjacent to the metal micro-nano structure, such as Δλ ≈ Δz / (5 ~ 10).

[0011] However, filter arrays based on metal micro / nano structures contain many filter units, such as hundreds. To achieve dimensional modulation of the structural parameters of each filter unit in the direction perpendicular to the substrate plane, at least thousands of processes would be required, greatly increasing the difficulty, complexity, and cost of the process, which is impractical. On the other hand, changing the structural parameters of the metal micro / nano structures in the lateral direction within the substrate plane of each filter unit can be achieved in a few processes within the same batch, and has the characteristic of being compatible with planar processes.

[0012] Therefore, the design and fabrication of filter arrays based on metal micro / nano structures generally involve modifying the dimensions of the structural parameters of the metal micro / nano structures in the lateral direction to modulate the transmission spectrum of each filter unit, while keeping the dimensions of the structural parameters perpendicular to the substrate plane constant. Consequently, the spectral resolution of the spectral analysis module based on the metal micro / nano structure filter array is severely limited by the fabrication precision of the micro / nano fabrication equipment used, making it difficult to achieve high resolution.

[0013] In the description of this invention, the resolution of the spectral analysis module refers to its spectral resolution or wavelength resolution. Summary of the Invention

[0014] This invention provides a method for improving the resolution of a filter array-based spectral analysis module.

[0015] The spectral analysis module involved in the embodiments of the present invention includes a filter array and a detector array.

[0016] The filter array is composed of multiple filter units. Each filter unit includes a metal pattern layer and a dielectric thin film layer, wherein the metal pattern layer has a metal micro / nano structure, and the number of metal pattern layers and dielectric thin film layers is one or more.

[0017] The detector array is composed of its inherent multiple detector unit pixels. The detector array can be planned to consist of multiple detector elements, each detector element containing one or more detector unit pixels.

[0018] Each filter unit in the filter array corresponds to each detector unit in the detector array.

[0019] Before use, the filter array-based spectral analysis module needs to be pre-calibrated to obtain pre-calibration information. In the spectral detection of signal light from the target object, the pre-calibration information and the test information of the signal light need to be combined to obtain the spectrum of the signal light through data processing calculation.

[0020] The structural parameters of the metal micro / nano structures in the metal patterned layer of the filter unit and the thicknesses of each dielectric thin film layer are collectively referred to as the structural parameters of the filter unit. The micro / nano structures refer to structures whose characteristic structural parameters are on the micrometer or nanometer scale, such as in the range of approximately 1 nanometer to 100 micrometers.

[0021] The structural parameters of the different filter units in the filter array should not be completely identical, meaning that one or more of the structural parameters are different. If there are two or more filter units with completely identical structural parameters in the filter array, then while retaining one of them, the relevant data generated by the other identical filter units can be considered invalid or subject to other special processing. Filter units with not completely identical structural parameters have different transmission spectra.

[0022] The transmission spectrum of the filter unit in the filter array can be a spectrum with passband characteristics, stopband characteristics, long-wavelength pass characteristics, or short-wavelength pass characteristics, or a spectrum composed of multiple spectral peaks and valleys. The characteristic wavelength of the transmission spectrum of the filter unit can be the center wavelength or peak wavelength of the spectral peak with passband characteristics, the center wavelength or valley wavelength of the spectral valley with stopband characteristics, the center wavelength of the transition band between the passband and stopband of the spectrum with long-wavelength pass characteristics or short-wavelength pass characteristics, or the peak wavelength of a certain spectral peak or the valley wavelength of a certain spectral valley in a spectrum with multiple spectral peaks or valleys.

[0023] The present invention provides a method for improving the resolution of a spectral analysis module based on the aforementioned filter array. This method mainly involves planning the layout of structural parameter variables of each filter unit in the filter array, and fabricating and controlling the lateral and longitudinal structural parameters of the filter units separately based on different fabrication processes. This overcomes the limitation on the resolution of the spectral analysis module caused by the insufficient control precision of the lateral structural parameter variables of the filter units due to the limited precision of micro-nano fabrication processes. The method is described below:

[0024] Suppose that the structural parameters of each filter unit in the filter array include its lateral structural parameters and its longitudinal structural parameters.

[0025] The lateral structural parameters of the filter unit refer to the various structural parameters of the metal micro-nano structures in the metal pattern layer of the filter unit within the plane of the metal pattern layer. For example, for a metal pattern layer with a periodic island-shaped metal thin film block structure, these parameters include the structural period and structural parameters describing the shape and size of each metal thin film block (such as the length and width of a rectangle, the radius of a circle, etc.).

[0026] The longitudinal structural parameters of the filter unit refer to the various structural parameters of the filter unit in the direction perpendicular to the filter array plane, such as the thickness of the metal pattern layer and the thickness of each dielectric thin film layer.

[0027] Each filter unit in the filter array is divided into several filter unit groups.

[0028] All filter units in the filter unit group are connected to form a region, and the regions of different filter unit groups do not overlap with each other.

[0029] In the filter array, different filter units within the same filter unit group have not exactly the same lateral structural parameters, but have exactly the same longitudinal structural parameters.

[0030] The filter units in the different filter unit groups in the filter array have not completely identical longitudinal structural parameters.

[0031] In the filter array, the corresponding filter units in different filter unit groups may have the same lateral structural parameters, but not exactly the same longitudinal structural parameters.

[0032] The "lateral structural parameters" and "longitudinal structural parameters" mentioned above can each include multiple specific structural parameters. "Completely identical" means that all included structural parameters are the same, while "not completely identical" means that one or more of the included structural parameters are different.

[0033] During the fabrication of the filter array, the metal micro-nano structures in the metal patterned layers of all filter units in all filter unit groups can be fabricated in the same process flow; dielectric thin film layers with one or more different longitudinal structural parameters in different filter unit groups can be fabricated in each filter unit group in multiple steps through repeatable process flow.

[0034] The main features and advantages of this invention are described below:

[0035] The method provided by the present invention involves modulating both the lateral and longitudinal structural parameters of each filter unit in the filter array.

[0036] The method provided by this invention plans the layout of structural parameter variables of each filter unit in the filter array, dividing all filter units into several filter unit groups containing multiple filter units. By modulating the longitudinal structural parameters of the filter units between different filter unit groups, the method achieves fine-grained control over the step size of characteristic wavelength changes in the transmission spectrum of different filter units in the filter array, thereby significantly improving the resolution of the spectral analysis module based on the filter array.

[0037] The number of filter unit groups in the filter array is much smaller than the number of individual filter units, and the area of ​​the filter unit groups is much larger than the area of ​​individual filter units. Therefore, the fabrication process of the dielectric thin film layer in filter units with different longitudinal structural parameters in different filter unit groups can be greatly simplified (lower requirements for pattern fabrication processes such as photolithography, and fewer repetitions of related processes). Compared to changing the thickness of the dielectric thin film layer in each filter unit, the process requirements and complexity are significantly reduced.

[0038] In summary, the control of the lateral structural parameters of each filter unit in the filter array is based on a high-precision patterning process (e.g., the control precision of structural parameters is approximately 5–20 nm), and is carried out in a single, non-repetitive process flow to achieve low-resolution control of the spectral analysis module. Meanwhile, the control of the longitudinal structural parameters of each filter unit in the filter array is based on a high-precision thin-film deposition process, combined with a low-precision patterning process (e.g., the control precision of structural parameters is less than 10 μm), using a repetitive process flow to deposit dielectric thin film layers of different thicknesses within different filter unit groups. This achieves high resolution for the spectral analysis module based on the low resolution achieved through lateral structural parameter control described above. Attached Figure Description

[0039] Figure 1 This is a side view schematic diagram of the filter array and detector array in the spectral analysis module according to an embodiment of the present invention.

[0040] Figure 2 This is a side view schematic diagram of the filter unit in the filter array of the spectral analysis module according to an embodiment of the present invention, which is a one-dimensional periodic structure (a) or a two-dimensional periodic structure (b).

[0041] Figure 3 This is a schematic cross-sectional view of an exemplary filter unit with a different layered structure in the longitudinal direction perpendicular to the substrate plane in the filter array of the spectral analysis module according to an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the planar distribution of filter units and filter unit groups in the filter array of the spectral analysis module according to an embodiment of the present invention. Detailed Implementation

[0043] To illustrate the technical content, structural features, objectives, and effects of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0044] The following embodiments are exemplary embodiments and may have different forms or variations, and should not be construed as being limited to the descriptions given herein. In the description of the structures in the embodiments of the present invention, expressions such as "on" can include "on" in a non-contact manner and "on" in a contact manner; expressions such as "below" can include "below" in a non-contact manner and "below" in a contact manner; expressions such as "including" mean "including but not limited to...".

[0045] Figure 1 The diagram shows a side view of the filter array 100 and detector array 200 in a spectral analysis module according to an embodiment of the present invention.

[0046] The filter array 100 is composed of multiple filter units 110. Each filter unit 110 contains a metal micro / nano structure. Different filter units 110 in the filter array 100 have different structural parameters and transmission spectral characteristics.

[0047] The detector array 200 contains multiple detector elements 210, each corresponding to a filter element 110 in the filter array 100. Each detector element 210 contains one or more detector unit pixels. A detector unit pixel is the smallest array unit inherent in the detector array 200.

[0048] Assume that both the filter array 100 and the detector array 200 have J array elements. The filter elements 110 in the filter array 100 are sequentially labeled as: F1, F2, F3, ..., F... j F J The detector elements 210 in the detector array 200 are sequentially labeled as: D1, D2, D3, ..., D j ... D J They correspond to filter units 110: F1, F2, F3, ..., F j F J .

[0049] The filter array 100 and the detector array 200 can be assembled separately with some kind of support structure, or they can be stacked together in contact with some transparent medium as an intermediate medium.

[0050] In the spectral analysis module, after the signal light is collected, it is irradiated onto the filter array 100 after passing through the beam shaping optical path. The transmitted light through different filter units 110 in the filter array 100 is irradiated onto the corresponding detector units 210. After the optical signals received by each detector unit 210 are converted into electrical signals, the spectral reconstruction is achieved through back-end data processing and calculation.

[0051] Figure 2 The diagram shows a side view of the filter unit 110 in the filter array 100 of the spectral analysis module according to an embodiment of the present invention, which is a one-dimensional or two-dimensional periodic structure. Figure 2 (a) and Figure 2 In the example shown in (b), the filter unit 110 includes a substrate 111, dielectric thin film layers 113 and 114 with different refractive indices, and a metal patterned layer 112 with a metal micro / nano structure.

[0052] The substrate 111 is a transparent medium with a thickness of tens of micrometers to several millimeters, or a transparent medium with a thickness of tens of nanometers to hundreds of micrometers located on the detector array.

[0053] The shape and morphology of the metal micro-nano structures and their arrays in the metal pattern layer 112 can be any form that meets the requirements of the filter array described in this invention, and there are no specific limitations here, but they can all be included within the scope of application of the method provided in this invention.

[0054] Figure 3 A schematic cross-sectional view of an exemplary example of a filter unit 110 with a layered structure having different characteristics in a filter array 100 of a spectral analysis module according to an embodiment of the present invention is shown. Figure 3 The structure shown in (a) corresponds to Figure 2 The structure shown in the figure. Figure 3 The structure shown in (b) is Figure 3 In the structure shown in (a), a dielectric thin film layer 115 is covered on the metal patterned layer 112. Figure 3 In the structure shown in (c), dielectric thin film layers 113 and 114 with different refractive indices are located on the metal pattern layer 112 and the substrate 111. Figure 3 The structure shown in (d) is... Figure 3 In the structure shown in (a), above the metal pattern layer 112, there are dielectric thin film layers 116 and 117 with different refractive indices. Figure 3 The structures shown in (a)-(d) are exemplary examples, in which the dielectric thin film layers with different refractive indices (such as 113 and 114, 116 and 117) may be not only two layers, but also one layer or more layers.

[0055] In the description of this invention, "dielectric thin film layer" refers to a layer similar to... Figure 3 The dielectric thin film layers 113, 114, 115, 116, and 117 in the illustrated example, and other similar dielectric thin film layers present near the metal pattern layer, are collectively referred to as such.

[0056] Figure 4 This diagram illustrates the planar distribution of filter units 110 and filter unit groups 120 in the filter array 100 of the spectral analysis module according to an embodiment of the present invention.

[0057] All filter units 110 in the filter array 100 are planned as I filter unit groups 120, and each filter unit group 120 includes J filter units 110 (Note: the number of filter units 110 in each filter unit group 120 may be different, but is set to be the same here for the convenience of unified expression and description), that is, there are a total of I×J filter units 110 in the filter array 100.

[0058] like Figure 4 As shown, F ij (i = 1, 2, ..., I; j = 1, 2, ..., J) represent each filter unit 110 in the filter array 100, i.e., filter unit 110F. ij It is the j-th filter unit 110 located in the i-th filter unit group 120 of the filter array 100.

[0059] In the following formula, S is used ij To represent filter unit 110F ij Structural parameters:

[0060] S ij =(L ij V ij )=(p ij ,a ij ,b ij ,…;t mij ,t d (1) ij ,t d (2) ij ,…)

[0061] Where: L ij =(p ij ,a ij ,b ij ,…) indicates filter unit 110F ij Lateral structural parameters, such as p ij ,a ij ,b ij... represent the structural parameters describing the period, shape, and size of the metal micro / nanostructure within the metal patterned layer; V ij =(t mij ,t d (1) ij ,t d (2) ij ,…) indicates filter unit 110F ij The longitudinal structural parameters, such as t mij ,t d (1) ij ,t d (2) ij ... represents the thickness (t) of the metal pattern layer. mij ) and the thickness of each dielectric thin film layer (t) d (1) ij ,t d (2) ij ,…).

[0062] Generalized implementation example:

[0063] In the design of the filter array 100, for example, in the same (e.g., the i-th, i = 1, 2, ..., I) filter unit group 120, each filter unit 110F ij The lateral structural parameter L of (j=1,2,…,J) ij =(p ij ,a ij ,b ij At least one of the terms in (, …) must be distinct, but their longitudinal structural parameter V ij =(t mij ,t d (1) ij ,t d (2) ij All items in (,…) are exactly the same; for different filter unit groups 120, that is, for different i (i=1,2,…,I), where filter unit 110F ij Longitudinal structural parameter V ij =(t mij ,t d (1) ij ,t d (2) ij The filter elements 110F, which belong to different filter element groups 120, are all different from each other, while the filter elements 110F, which have the same j (j = 1, 2, ..., J), are all different from each other.ij Lateral structural parameter L ij =(p ij ,a ij ,b ij ,...) can be the same or different.

[0064] In the design of the filter array 100, in order to reduce the complexity and cost of the manufacturing process, the number of structural parameter variables in the structural parameters of the filter unit 110, especially its longitudinal structural parameter V, can be minimized. ij =(t mij ,t d (1) ij ,t d (2) ij The number of structural parameter variables in (,…). Furthermore, for longitudinal structural parameters, it is best to change only the thickness of one of the dielectric thin film layers (e.g., t). d (1) ij , or t d (2) ij One of them), while generally not changing the thickness of the metal pattern layer (t). mij ).

[0065] Optimized implementation example:

[0066] The following embodiments illustrate the preferred design of the structural parameter variables of each filter unit 110 in the filter array 100.

[0067] In such Figure 4 In the filter array 100 shown, each filter unit 110 in different filter unit groups 120 has the same lateral structural parameters, that is...

[0068] L 11 =L 21 =L 31 =…=L i1 =…=L I1 =L1(p1,a1,b1,…),

[0069] L 12 =L 22 =L 32 =…=L i2 =…=L I2 =L2(p2,a2,b2,…),

[0070] L 13 =L 23 =L 33 =…=L i3 =…=LI3 =L3(p3,a3,b3,…),

[0071] ...and so on...

[0072] L 1J =L 2J =L 3J =…=L iJ =…=L IJ =L J (p J ,a J ,b J ,…).

[0073] However, the individual filter units 110 within each filter unit group 120 have slightly different lateral structural parameters, namely...

[0074] L1(p1,a1,b1,…)≠L2(p2,a2,b2,…)≠L3(p3,a3,b3,…)≠…≠L j (p j ,a j ,b j ,…)…≠L J (p J ,a J ,b J ,…).

[0075] Here, L j (p j ,a j ,b j In the parameters of (j = 1, 2, ..., J), for different j, there may be one or more terms (such as p). j and a j The difference is that other parameters (such as b) are different. j ,…)same.

[0076] Furthermore, each filter unit 110 in each filter unit group 120 should have the same longitudinal structural parameters, i.e.

[0077] V 11 =V 12 =V 13 =…=V 1j =…=V 1J =V1(t d1 ),

[0078] V 21 =L 22 =V 23 =…=V 2j =…=V 2J =V2(t) d2 ),

[0079] V 31 =V 32 =V 33 =…=V 3j =…=V 3J =V3(t d3 ),

[0080] ...and so on...

[0081] V I1 =V I2 =V I3 =…=V Ij =…=V IJ =V I (t dI ).

[0082] However, the longitudinal structural parameters of the filter units 110 in different filter unit groups 120 are different, that is...

[0083] V1(t d1 )≠V2(t d2 )≠V3(t d3 )≠…≠V i (t di )…≠V I (t dI ).

[0084] Where t di (i = 1, 2, ..., I) is t d (1) ij ,t d (2) ij The thickness of one of the dielectric thin film layers referred to in … can be set to be the same for all filter units 110 in the filter array 100, while the thicknesses of the other dielectric thin film layers and the metal pattern layer can be set to be the same.

[0085] In addition, the number I of the filter unit groups 120 should not be excessively large, and should be much smaller than the number J of the filter units 110 in each filter unit group 120, that is, I<<J. For example, (I,J) can be designed as (4,100), (5, 80) or (6, 100), so that the filter array 100 has I×J=400 or 600 filter units 110. Thereby, the step size of the characteristic wavelength variation of the transmission spectrum of the filter units 110 within a certain spectral band range [λ1,λ2] can be obtained as approximately Δλ=(λ2-λ1) / (I×J) (here, the variation of the structural parameters is set such that the characteristic wavelengths are approximately uniformly distributed within the spectral band range). By increasing I and J, a smaller Δλ can be obtained, which is beneficial to improving the resolution of the spectral analysis module. The increase of J is mainly limited by the process precision of micro-nano processing equipment, while the increase of I will correspondingly raise the complexity and cost of the processing and preparation process. Therefore, the selection of I and J requires comprehensive consideration of process precision and cost.

[0086] In the processing and preparation process of the filter array 100 described above, the metal pattern layers in all the filter units 110 of all the filter unit groups 120 can be processed and prepared in the same process flow; the dielectric thin film layer with different thicknesses in different filter unit groups can be separately prepared in each filter unit group 120 in multiple steps through several (e.g., I times) repeated process flows.

[0087] The control of the lateral structural parameters in all the filter units 110 described above needs to be implemented based on a high-precision pattern preparation process (for example, using high-precision EUV extreme ultraviolet lithography, electron beam lithography, nanoimprint and other equipment, with a pattern dimension control precision of at least about 5 to 20 nm, for example).

[0088] For the control of the longitudinal structural parameters in different filter unit groups 120 described above, a high-precision thin film deposition process (such as using an advanced optical coating machine) can be adopted; the deposition of the dielectric thin film layers with different thicknesses in different filter unit groups 120 involved therein can be implemented through a repeated process flow in combination with a low-precision pattern preparation process (for example, using an ordinary ultraviolet lithography machine, which is required to have a control precision of structural parameters of less than 10 μm).

[0089] In the above method, the low resolution of the spectral analysis module is achieved by controlling the lateral structural parameters of each filter unit; on this basis, the high resolution of the spectral analysis module is further achieved by controlling the longitudinal structural parameters of each filter unit within each filter unit group respectively.

[0090] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for improving resolution using a spectral analysis module based on a filter array, characterized in that: The spectral analysis module includes at least a filter array and a detector array. The filter array consists of multiple filter units, and the detector array has multiple detector units, each consisting of at least one detector unit pixel. Each filter unit in the filter array includes at least one metal pattern layer and a dielectric thin film layer. The metal pattern layer contains metal micro / nano structures. Each filter unit in the filter array, with different structural parameters, has different transmission spectral characteristics. The layout of the structural parameter variables of each filter unit in the filter array is planned, dividing all filter units into several filter unit groups containing multiple filter units. This ensures that the filter units within each filter unit group have the same vertical structural parameters. The lateral and vertical structural parameters of the filter units in each filter unit group are fabricated and controlled separately based on different fabrication processes. By modulating the vertical structural parameters of the filter units between different filter unit groups, the step size of the characteristic wavelength variation in the transmission spectrum of different filter units in the filter array can be precisely controlled, thereby significantly improving the resolution of the spectral analysis module based on the filter array.

2. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: The filter units in the filter array are divided into several filter unit groups. All the filter units in the filter unit group are connected to form a region, and the regions of different filter unit groups do not overlap with each other.

3. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: Different filter units in the same filter unit group in a filter array have not exactly the same lateral structural parameters, but have exactly the same longitudinal structural parameters.

4. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: The filter units in the different filter unit groups in the filter array have not exactly the same longitudinal structural parameters.

5. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: In a filter array, corresponding filter units in different filter unit groups have the same lateral structural parameters, but not exactly the same longitudinal structural parameters.

6. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: The control of the lateral structural parameters of each filter unit in the filter array is based on a high-precision patterning process, with a control precision of less than 50 nanometers, and the fabrication is carried out in a single process flow that does not require repetition.

7. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: The control of the longitudinal structural parameters of each filter unit in the filter array is based on a high-precision thin film deposition process, which can be combined with a low-precision patterning process. The control accuracy of the structural parameters is less than 50 micrometers. Through several repetitive process flows, dielectric thin film layers of different thicknesses can be prepared in different filter unit groups.

8. The method for improving resolution of a spectral analysis module based on a filter array as described in claim 1, characterized in that: The low resolution of the spectral analysis module is achieved by controlling the lateral structural parameters of each filter unit; furthermore, the high resolution of the spectral analysis module is achieved by controlling the longitudinal structural parameters of each filter unit.

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