Multispectral filter

Abstract

The invention provides a multispectral filter. The multispectral filter comprises a substrate; the first refraction layer is distributed on the surface of the substrate; the first refraction layer comprises a plurality of first step parts, and at least two first step parts are different in height in the direction perpendicular to the substrate; the induced transmission layer is distributed on the surface of the first refraction layer away from the substrate; the induced transmission layer comprises a plurality of second step parts, a metal layer and a plurality of third step parts; the second refraction layer is distributed on the surface, away from the first refraction layer, of the induction transmission layer; the second refraction layer comprises a plurality of fourth step parts, and at least two fourth step parts are different in height in the direction perpendicular to the substrate; the first step part, the second step part, the metal layer, the third step part and the fourth step part are stacked to form a filtering channel; and the filtering channels with different heights are used for transmitting light with different target wavelengths. The problem that high spectral resolution and high light transmittance in a filter cannot be considered at the same time is solved, and the filter has good cut-off region inhibition and permeability.

Description

Technical Field

[0001] The present application relates to the field of filter technology, and in particular to a multi-spectral filter. Background Art

[0002] Spectrum represents the distribution of optical intensity with optical wavelength or optical frequency. Filter is an effective technical means to obtain spectral distribution.

[0003] In the prior art, a spectrum is usually formed using a traditional metal Fabry-Perot filter. This filter has low transmittance, a wide half-width range, and a low resolution of the generated spectrum. Another filter uses a stack of metal layers and dielectric layers to process the incident light. This filter has a small half-width and a high resolution of the generated spectrum, but the cutoff suppression is narrow, and it is necessary to add long and short wave filters to form an effective cutoff suppression. However, adding filters will increase the process difficulty and cost of the filter exponentially.

[0004] Therefore, it is now necessary to solve the problem of the filter's spectral resolution and transmittance being unable to be taken into account at the same time, as well as the problems of difficult process and high production cost. Summary of the invention

[0005] In view of this, the purpose of this application is to propose a multi-spectral filter that solves the problem that the filter's higher spectral resolution and higher transmittance cannot be taken into account at the same time, has good cutoff region suppression and transmittance, simplifies the production process, and reduces production costs.

[0006] In order to achieve one of the above purposes, the present application provides a multi-spectral filter, comprising:

[0007] substrate;

[0008] a first refractive layer, the first refractive layer being distributed on the surface of the substrate, and the first refractive layer being used for interfering light of a part of wavelengths;

[0009] The first refractive layer comprises a plurality of first stepped portions, at least two of the first stepped portions having different heights in a direction perpendicular to the substrate;

[0010] an induced transmission layer, the induced transmission layer being distributed on a surface of the first refractive layer away from the substrate;

[0011] The induced transmission layer includes a plurality of second step portions, a metal and a plurality of third step portions, at least two of the second step portions have different heights in a direction perpendicular to the substrate, and at least two of the third step portions have different heights in a direction perpendicular to the substrate;

[0012] A second refractive layer, which is distributed on the surface of the induced transmission layer away from the first refractive layer, and is used for interfering with light of some wavelengths;

[0013] The second refractive layer includes a plurality of fourth stepped portions, and at least two of the fourth stepped portions have different heights in a direction perpendicular to the substrate;

[0014] One first stepped portion, one second stepped portion, a metal layer, one third stepped portion and one fourth stepped portion are stacked in a direction perpendicular to the substrate to form a filtering channel;

[0015] The filtering channels with different heights are used for tuning light of different target wavelengths.

[0016] As a further improvement of the embodiment of the present application, both the first refractive layer and the second refractive layer include:

[0017] At least one first refractive material layer and at least one second refractive material layer, and the first refractive material layer and the second refractive material layer are alternately stacked;

[0018] The refractive index of the first refractive material layer is different from that of the second refractive material layer.

[0019] As a further improvement of the embodiment of the present application, the first refractive layer includes a plurality of first layer groups stacked in a direction perpendicular to the substrate, and each first layer group includes one first refractive material layer and one second refractive material layer. In the first layer group, the first refractive material layer and the second refractive material layer are sequentially stacked in a direction from far away from the induced transmission layer to close to the induced transmission layer;

[0020] The second refractive layer includes a plurality of second layer groups stacked in a direction perpendicular to the substrate, and each second layer group includes one first refractive material layer and one second refractive material layer. In the second layer group, the first refractive material layer and the second refractive material layer are sequentially stacked in a direction from far away from the induced transmission layer to close to the induced transmission layer.

[0021] As a further improvement of the embodiment of the present application, in one first stepped portion or one fourth stepped portion, the optical thickness of each first refractive material layer is one quarter of the target wavelength, and the optical thickness of each second refractive material layer is one quarter of the target wavelength.

[0022] As a further improvement of the embodiment of the present application, the induced transmission layer includes:

[0023] A first dielectric material layer, the metal layer, and a second dielectric material layer are sequentially stacked in a direction perpendicular to the substrate;

[0024] The thickness of the first dielectric material layer in the second stepped portions at different heights is different, and the thickness of the second dielectric material layer in the third stepped portions at different heights is different.

[0025] As a further improvement of the implementation manner of the present application, first dielectric material layers of different thicknesses are used to tune light of different target wavelengths, and second dielectric material layers of different thicknesses are used to tune light of different target wavelengths.

[0026] As a further improvement of the embodiment of the present application, the plurality of filter channels are arranged in an array along a first direction and a second direction on the surface of the substrate;

[0027] The first direction and the second direction are parallel to a surface of the substrate, and the first direction and the second direction are perpendicular to each other.

[0028] As a further improvement of the embodiment of the present application, the first refractive layer, the first dielectric material layer, the metal layer, the second dielectric material layer and the second refractive layer are sequentially made by a film layer patterning process.

[0029] The multi-spectral filter provided by the present application utilizes a first refractive layer, an induced transmission layer, and a second refractive layer which are stacked in sequence. After the incident light enters through the second refractive layer, the first refractive layer emits filtered light to form a spectrum. The induced transmission layer is used for admittance matching of the metal layer. The first refractive layer and the second refractive layer on both sides of the induced transmission layer serve as anti-reflection films for the induced transmission layer. By stacking the first refractive layer, the induced transmission layer, and the second refractive layer, good cutoff region suppression and transmittance can be taken into account, a high-resolution spectrum can be generated, and light energy loss can be reduced at the same time.

[0030] In addition, in the multi-spectral filter provided in the present application, the first refractive layer is distributed as a whole on the surface of the substrate, the induced transmission layer is distributed as a whole on the surface of the first refractive layer, and the second refractive layer is distributed as a whole on the surface of the induced transmission layer. The stacking of step portions of different heights in the above film layers directly forms a filtering channel that can tune different target wavelengths, thereby solving the problems of difficult processing technology and high cost of existing filters. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic diagram of a multi-spectral filter provided in one embodiment of the present application;

[0032] Figure 2 A schematic diagram of a filtering channel provided in one embodiment of the present application;

[0033] Figure 3Schematic diagram of a filtering channel provided in an embodiment of the present application;

[0034] Figure 4 Schematic diagram of an induced transmission layer provided in an embodiment of the present application.

[0035] Reference numerals: 10, substrate; 20, first refractive layer; 21, first refractive material layer; 22, second refractive material layer; 23, first stepped portion; 30, induced transmission layer; 31, first dielectric material layer; 32, metal layer; 33, second dielectric material layer; 34, second stepped portion; 35, third stepped portion; 40, second refractive layer; 41, fourth stepped portion; 50, filtering channel. Detailed implementation manners

[0036] To make the objectives, technical solutions, and advantages of the present application clearer and more understandable, the present application will be further described in detail below in conjunction with specific implementation manners and with reference to the accompanying drawings.

[0037] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meanings understood by those of ordinary skill in the art to which the present application belongs. The "first", "second", and similar terms used in the embodiments of the present application do not indicate any order, quantity, or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connection" or "connected" and similar terms are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Upper", "lower", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0038] A spectral filter is an instrument used for wavelength selection, which selects the light of the desired target wavelength from a multitude of wavelengths, and the light other than the target wavelength will be filtered and cannot pass through the filter. Spectral filters can be used for wavelength selection, noise filtering of optical amplifiers, gain equalization, optical multiplexing / demultiplexing, etc.

[0039] In the prior art, common filters include metal-dielectric Fabry-Perot filters and thin-film all-dielectric Fabry-Perot filters.

[0040] Among them, metal-dielectric Fabry-Perot filters usually have no sideband pass. However, due to the large absorption of the metal film, the performance improvement of the filter is limited, resulting in a very low peak transmittance in the target wavelength range, low transmitted energy. If the peak transmittance is increased, the half-width will be sacrificed, resulting in a larger half-width, so that the shapes of the stop band and the pass band cannot be used, and the filter channels will crosstalk, reducing the spectral resolution of the filter.

[0041] The thin-film all-dielectric Fabry-Perot filter is a structure commonly used in narrowband transmission filters, allowing a very narrow transmission bandwidth. However, the disadvantage is that the suppression range in the stop region is very limited, and it is impossible to form a broadband transmission filter. The filtering range of the filter can only stay within a limited range. And in a multispectral filter, the wider the spectrum and the more channels, the greater the difficulty in design and manufacturing. For this reason, it is necessary to add a cut-off filter to eliminate unnecessary bandwidth suppression. This means of adding an additional cut-off filter will cause the total number of layers to become very high, and the processing difficulty and processing cost will increase accordingly.

[0042] Therefore, the existing spectral filters cannot well balance the bandwidth width and the transmittance, have the problem of limited suppression in the stop region, and also have the problems of high production cost and complex process.

[0043] One embodiment of the present application proposes a multispectral filter, as Figure 1 shown, including a substrate 10, a first refractive layer 20, an induced transmission layer 30, and a second refractive layer 40. The first refractive layer 20 is distributed on the surface of the substrate 10, and the first refractive layer 20 is used to interfere with light of some wavelengths; the first refractive layer 20 includes a plurality of first stepped portions 23, and at least one first stepped portion 23 has different heights in the direction perpendicular to the substrate 10; the induced transmission layer 30 is distributed on the surface of the first refractive layer 20 away from the substrate 10, and the induced transmission layer 30 is used for admittance matching of the metal layer 32; the induced transmission layer 30 includes a plurality of second stepped portions 34, a metal layer 32, and a third stepped portion 35, at least two second stepped portions 34 have different heights in the direction perpendicular to the substrate 10, and at least two third stepped portions 35 have different heights in the direction perpendicular to the substrate 10; the second refractive layer 40 is distributed on the surface of the induced transmission layer 30 away from the first refractive layer 20, and the second refractive layer 40 is used to interfere with light of some wavelengths; the second refractive layer 40 includes a plurality of fourth stepped portions 41, and at least two fourth stepped portions 41 have different heights in the direction perpendicular to the substrate 10; one first stepped portion 23, one second stepped portion 34, the metal layer 32, the first third stepped portion 35, and one fourth stepped portion 41 are stacked in the direction perpendicular to the substrate to form a filtering channel 50; the filtering channels 50 with different heights are used to tune light of different target wavelengths.

[0044] In the multi-spectral filter provided in this embodiment, the first refractive layer 20 and the second refractive layer 40 act as anti-reflection films of the induced transmission layer 30, eliminating the reflection of the equivalent admittance of the induced transmission layer 30, inducing the metal layer 32 to produce the maximum transmittance, and at the same time, the non-target wavelength region has a good cut-off region suppression due to the reflection of the metal layer 32, which can take into account good half-width and transmittance, and finally generate a high-resolution spectrum while reducing light energy loss.

[0045] When a first step portion 23 of the first refractive layer 20, a second step portion 34 of the induced transmission layer 30, a metal layer 32, a third step portion 35, and a fourth step portion 41 of the second refractive layer 40 are stacked, a filter channel 50 is formed. According to the target wavelength tuned in the filter channel 50, the heights of the first step portion 23, the second step portion 34, the third step portion 35, and the fourth step portion 41 are set.

[0046] It should be noted that the incident light will be refracted in the first refractive layer 20 and the second refractive layer 40, so that light within a certain range of wavelengths will interfere therein, and the wavelength range of the light that interferes will be different according to the height of the first stepped portion 23; the second refractive layer 40 is similar, and the range of the light that interferes will be different according to the height of the fourth stepped portion 41. Therefore, according to the light of different target wavelengths corresponding to different filter channels 50, the first stepped portion 23 is set to different thicknesses, and the fourth stepped portion 41 is set to different thicknesses.

[0047] For ease of explanation, the side of the first refractive layer 20 close to the substrate 10 is described as the bottom, and the side away from the substrate 10 is described as the top. The incident light enters from the top of the multi-spectral filter, is filtered by the filter channels 50 at different heights, and the target wavelength is transmitted to the substrate 10 to form a spectral distribution.

[0048] In this embodiment, the first refractive layer 20 is integrally distributed on the surface of the substrate 10. The first refractive layer 20 has a stepped structure and is divided into a plurality of first stepped portions 23 according to the stepped positions of different heights. Similarly, the induced transmission layer 30 is integrally distributed on the surface of the first refractive layer 20. The induced transmission layer 30 has a stepped structure and includes a second stepped portion 34 and a third stepped portion 35 which are distinguished according to the stepped positions of different heights. Inside the induced transmission layer 30, in the direction perpendicular to the substrate, the second stepped portion 34, the metal layer 32, and the third stepped portion 35 are stacked. The second refractive layer 40 is integrally distributed on the surface of the induced transmission layer 30. The second refractive layer 40 has a stepped structure and is divided into a plurality of fourth stepped portions 41 according to the stepped positions of different heights. Therefore, a plurality of filtering channels 50 perpendicular to the substrate 10 are formed by stacking the first refractive layer 20, the induced transmission layer 30, and the second refractive layer 40 which are distributed parallel to the substrate 10. This reduces the production cost and the complexity of the production process. In addition, compared with the filtering channels 50 in other splicing forms, in this embodiment, adjacent filtering channels 50 are formed only by the step difference of the structure of the film layer itself, which significantly improves the connection accuracy between adjacent filtering channels 50.

[0049] In a specific embodiment of the present application, the substrate 10 is made of a transparent material. The spectra formed by a plurality of filtering channels 50 are transmitted to the lower side of the substrate 10 to form a spectrogram. The substrate 10 only serves as a supporting bottom for integrating a plurality of filtering channels 50. In another specific embodiment of the present application, a plurality of optical sensors are provided in the substrate 10. The optical sensors correspond to the filtering channels 50 one by one. Therefore, the spectra generated by the plurality of filtering channels 50 are transmitted to a computer system through the optical sensors.

[0050] In the embodiments of the present application, as Figure 3 shown, both the first refractive layer 20 and the second refractive layer 40 include at least one first refractive material layer 21 and at least one second refractive material layer 22. The first refractive material layer 21 and the second refractive material layer 22 are alternately laminated; the refractive index of the first refractive material layer 21 is different from that of the second refractive material layer 22.

[0051] In a specific embodiment, the first refractive material layer 21 is a high-refractive-index material layer with a relatively high refractive index, and the second refractive material layer 22 is a low-refractive-index material layer with a relatively low refractive index. The high-refractive-index material layer and the low-refractive-index material layer are alternately laminated.

[0052] In the embodiments of the present application, as Figure 3As shown, the first refractive layer 20 includes a plurality of first layer groups stacked in a direction perpendicular to the substrate. Each first layer group includes a first refractive material layer 21 and a second refractive material layer 22. In the first layer group, the first refractive material layer 21 and the second refractive material layer 22 are sequentially stacked in a direction from away from the induced transmission layer 30 to close to the induced transmission layer 30;

[0053] The second refractive layer 40 includes a plurality of second layer groups stacked in a direction perpendicular to the substrate 10. Each second layer group includes a first refractive material layer 21 and a second refractive material layer 22. In the second layer group, the first refractive material layer 21 and the second refractive material layer 22 are sequentially stacked in a direction from away from the induced transmission layer 30 to close to the induced transmission layer 30.

[0054] The first refractive material layer 21 and the second refractive material layer 22 in the first refractive layer 20 and the second refractive layer 40 are symmetrically distributed on both sides of the induced transmission layer 30. The high-refractive-index material layer and the low-refractive-index material layer with reversed order in the first refractive layer 20 are used to adjust the reflection phase or broaden the reflection bandwidth and optimize the interference conditions. After the incident light is transmitted through the induced transmission layer 30, the propagation path in the first refractive layer 20 is mirror-symmetric with the second refractive layer 40.

[0055] In an embodiment of the present application, in a first stepped portion 23 or a fourth stepped portion 41, the optical thickness of each first refractive material layer 21 is one quarter of the target wavelength, and the optical thickness of each second refractive material layer 22 is one quarter of the target wavelength.

[0056] In other embodiments of the present application, the first refractive layer 20 includes a plurality of first layer groups stacked in a direction perpendicular to the substrate 10. Each first layer group includes a first refractive material layer 21 and a second refractive material layer 22. The second refractive material layer 22 and the first refractive material layer 21 are sequentially stacked in a direction from away from the induced transmission layer 30 to close to the induced transmission layer 30; the second refractive layer 40 includes a plurality of second layer groups stacked in a direction perpendicular to the substrate 10. Each second layer group includes a first refractive material layer 21 and a second refractive material layer 22. The second refractive material layer 22 and the first refractive material layer 21 are sequentially stacked in a direction from away from the induced transmission layer 30 to close to the induced transmission layer 30.

[0057] In a specific embodiment of the present application, the first refractive material layer 21 with a higher refractive index is set as a titanium dioxide material, and the second refractive material layer 22 with a lower refractive index is set as a silicon dioxide material.

[0058] In an embodiment of the present application, as Figure 3 and Figure 4As shown, the induced transmission layer 30 includes a first dielectric material layer 31, a metal layer 32, and a second dielectric material layer 33 that are sequentially stacked in a direction perpendicular to the substrate 10; the thickness of the first dielectric material layer 31 in the second stepped portions 34 with different heights is different, and the thickness of the second dielectric material layer 33 in the third stepped portions 35 with different heights is different. Among them, the first dielectric material layer 31 and the second dielectric material layer 33 have a relatively high light transmittance, and the metal layer 32 has excellent cut-off region suppression. Stacking the first dielectric material layer 31, the metal layer 32, and the second dielectric material layer 33 to form the induced transmission layer 30, the first dielectric material layer 31 and the second dielectric material layer 33 make the admittance of the metal layer an integer, enabling the induced transmission layer 30 to have both excellent light transmittance and excellent cut-off region suppression, and the light of the tuned target wavelength has a good half-width. In the filtering channels 50 with different target wavelengths, the thickness of the first dielectric material layer 31 is different, and the thickness of the second dielectric material layer 33 is different, to tune the light of different target wavelengths.

[0059] It should be noted that the induced transmission layer 30 is stacked by three types of film layers, where the first dielectric material layer 31 is a stepped structure, and the second dielectric material layer 33 is a stepped structure. The first dielectric material layer 31 includes a plurality of second stepped portions 34, and the heights of at least two second stepped portions 34 are different. The second dielectric material layer 33 includes a plurality of third stepped portions 35, and the heights of at least two third stepped portions 35 are different.

[0060] In a specific embodiment of the present application, the first dielectric material layer 31 and the second dielectric material layer 33 are set as dielectric transparent materials, and SiO material or TiO material can be selected. The metal layer 32 is set as silver or aluminum, etc.

[0061] In an embodiment of the present application, the thickness of the metal layer 32 in the second stepped portions 34 with different heights is the same. The metal layer 32 is used to improve the cut-off region suppression ability of the induced transmission layer 30 without affecting the transmitted target wavelength. At the same time, in order to avoid too low light transmittance of the metal layer 32, the metal layer 32 needs to be set with an extremely thin thickness. Therefore, an extremely thin metal layer 32 with the same thickness is set in each filtering channel 50, which can improve the cut-off region suppression ability of the induced transmission layer 30 while minimizing the impact on the light transmittance of the induced transmission layer 30.

[0062] In an embodiment of the present application, the first dielectric material layer 31 with different thicknesses is used to tune the light of different target wavelengths, and the second dielectric material layer 33 with different thicknesses is used to tune the light of different target wavelengths.

[0063] Set the thickness of the first dielectric material layer 31 and the thickness of the second dielectric material layer 33 according to the target wavelength preset for the filtering channel. Therefore, the target wavelengths transmitted in different filtering channels 50 are different, and the thicknesses of the first dielectric material layer 31 and the second dielectric material layer 33 will change accordingly.

[0064] In a specific embodiment of the present application, the optical thickness of the first dielectric material layer 31 is a, the optical thickness of the second dielectric material layer 33 is a, and the target wavelength of the filtering channel 50 is b, where a ≤ 1 / 4b.

[0065] Design the optical thicknesses of the first dielectric material layer 31 and the second dielectric material layer 33 to be less than one - quarter of the target wavelength. The sum of the optical thickness of the first dielectric material layer 31 and the adjacent second refractive material layer 22 is one - quarter of the target wavelength; similarly, the sum of the optical thickness of the second dielectric material layer 33 and the adjacent second refractive material layer 22 is one - quarter of the target wavelength.

[0066] In a specific embodiment of the present application, the relationship between the optical thickness a of the first dielectric material layer 31 and the second dielectric material layer 33 and the target wavelength b of the filtering channel 50 can be: a = 1 / 4b, a = 1 / 8b, a = 1 / 16b, etc.

[0067] In a specific embodiment of the present application, the stacked structure in the multispectral filter can be expressed as: (HL)m - a(M)-metal - a(M)-(LH)m;

[0068] Where H is the first refractive material layer 21, L is the second refractive material layer 22, m represents the number of overlaps, a represents the optical thickness coefficient of the first dielectric material layer 31 or the second dielectric material layer 33, and M is a dielectric transparent material.

[0069] In an embodiment of the present application, as Figure 1 described, X in the figure represents the first direction, Y in the figure represents the second direction. A plurality of filtering channels 50 are arranged in an array along the first direction and the second direction on the surface of the substrate 10. The first direction and the second direction are parallel to the surface of the substrate, and the first direction and the second direction are perpendicular. The filtering channels 50 are array - distributed on the substrate 10. When incident light enters the multispectral filter at the same time, the generated multiple target wavelengths form an array - distributed spectrum.

[0070] In a specific embodiment, in the first direction, there are m filtering channels 50 arranged in an array, and in the second direction, there are n filtering channels 50 arranged in an array. The filtering channels 50 are distributed in the form of m*n.

[0071] In an embodiment of the present application, among the multiple filtering channels 50 arranged in an array along the first direction, the filtering channel 50 located at the central position has the maximum height, and the extension lengths of the filtering channels 50 distributed from the filtering channel 50 at the central position to both sides along the first direction gradually decrease. The filter is distributed in a form with a higher middle and lower sides, which is convenient for subsequent packaging and improves the stability of the filter structure.

[0072] In a specific embodiment of the present application, when the multiple filtering channels 50 are distributed in an m*n manner, the filtering channel 50 at the diagonal center position of the rectangular array has the longest extension length, and the extension lengths of the filtering channels 50 distributed from this filtering channel 50 to the surrounding along the first direction and the second direction gradually decrease. The multiple filtering channels 50 form a slope-like structure with a higher middle and lower surrounding.

[0073] In an embodiment of the present application, the first refractive layer 20, the first dielectric material layer 31, the metal layer 32, the second dielectric material layer 33, and the second refractive layer 40 are sequentially formed by a film patterning process, forming a stepped layer structure.

[0074] In a specific embodiment, the film patterning process includes a mask plate vacuum evaporation process, a mask plate lithography process, an electron beam etching process, a 3D printing process, a laser direct writing process, or a nanoimprint process, etc.

[0075] In this specific embodiment, by means of overlay or overplating, first a whole-surface first refractive material layer 21 is fabricated on the substrate 10, and then a whole-surface second refractive material layer 22 is fabricated. Fabrication is repeated in the order from the first refractive material layer 21 to the second refractive material layer 22 to form a whole-surface first refractive layer 20. Then, a first dielectric material layer 31 is fabricated on the first refractive layer 20, a metal layer 32 is continuously fabricated on the first dielectric material layer 31, and a second dielectric material layer 33 is continuously fabricated on the metal layer 32 to form a whole-surface induced transmission layer 30. Continuing to fabricate a second refractive material layer 22 and a first refractive material layer 21 on the induced transmission layer in sequence, where the number of stacked layers of the second refractive material layer 22 and the first refractive material layer 21 here is the same as the number of stacked layers in the first refractive layer 20. Finally, the stacking order and the number of stacked layers of the first refractive material layer 21 and the second refractive material layer 22 are mirror-symmetrically distributed with the induced transmission layer 30 as the center.

[0076] The multi-spectral filter proposed in the embodiment of the present application has a wider cut-off region suppression compared with the filter with all-dielectric light transmission treatment; compared with the filter in the form of a stacked metal layer and dielectric layers, the light energy absorption ability of the induced transmission layer 30 is less than that of the metal layer, having a higher light transmittance and a narrower bandwidth, improving the spectral resolution.

[0077] Those of ordinary skill in the art should understand that any discussion of the above embodiments is exemplary only and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above, and for the sake of brevity, they are not provided in detail.

[0078] The embodiments of the present application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A multi-spectral filter, characterized in that: include: substrate; A first refractive layer, the first refractive layer is distributed on the surface of the substrate, and the first refractive layer is used to interfere with light of a part of wavelengths; The first refractive layer comprises a plurality of first stepped portions, at least two of the first stepped portions having different heights in a direction perpendicular to the substrate; an induced transmission layer, the induced transmission layer being distributed on a surface of the first refractive layer away from the substrate; The induced transmission layer comprises a plurality of second step portions, a metal layer and a plurality of third step portions, at least two of the second step portions have different heights in a direction perpendicular to the substrate, and at least two of the third step portions have different heights in a direction perpendicular to the substrate; a second refractive layer, the second refractive layer being distributed on a surface of the induced transmission layer away from the first refractive layer, and the second refractive layer being used for interfering light of a part of wavelengths; The second refractive layer comprises a plurality of fourth step portions, and at least two of the fourth step portions have different heights in a direction perpendicular to the substrate; One of the first step portions, one of the second step portions, a metal layer, one of the third step portions and one of the fourth step portions are stacked in a direction perpendicular to the substrate to form a filtering channel; The filter channels at different heights are used to tune lights of different target wavelengths.

2. The multi-spectral filter according to claim 1, characterized in that: The first refractive layer and the second refractive layer both include: at least one first refractive material layer and at least one second refractive material layer, wherein the first refractive material layer and the second refractive material layer are alternately stacked; The refractive index of the first refractive material layer is different from the refractive index of the second refractive material layer.

3. The multi-spectral filter according to claim 2, characterized in that: The first refractive layer comprises a plurality of first layer groups stacked in a direction perpendicular to the substrate, each of the first layer groups comprises a first refractive material layer and a second refractive material layer, and in the first layer groups, the first refractive material layer and the second refractive material layer are sequentially stacked in a direction away from the induced transmission layer and close to the induced transmission layer; The second refractive layer includes a plurality of second layer groups stacked in a direction perpendicular to the substrate, each of the second layer groups includes a first refractive material layer and a second refractive material layer, and in the second layer groups, the first refractive material layer and the second refractive material layer are stacked sequentially in a direction away from the induced transmission layer to close to the induced transmission layer.

4. The multi-spectral filter according to claim 2, characterized in that: In one of the first stepped portions or one of the fourth stepped portions, the optical thickness of each of the first refractive material layers is one quarter of the target wavelength, and the optical thickness of each of the second refractive material layers is one quarter of the target wavelength.

5. The multi-spectral filter according to claim 1, characterized in that: The transmission-inducing layer comprises: A first dielectric material layer, the metal layer, and a second dielectric material layer are sequentially stacked in a direction perpendicular to the substrate; The thickness of the first dielectric material layer in the second stepped portions at different heights is different, and the thickness of the second dielectric material layer in the third stepped portions at different heights is different.

6. The multi-spectral filter according to claim 2, characterized in that: The first dielectric material layers with different thicknesses are used to tune the light with different target wavelengths, and the second dielectric material layers with different thicknesses are used to tune the light with different target wavelengths.

7. The multi-spectral filter according to claim 1, characterized in that: The plurality of filter channels are arranged in an array along a first direction and a second direction on the surface of the substrate; The first direction and the second direction are parallel to a surface of the substrate, and the first direction and the second direction are perpendicular to each other.

8. The multi-spectral filter according to claim 5, characterized in that: The first refractive layer, the first dielectric material layer, the metal layer, the second dielectric material layer and the second refractive layer are sequentially manufactured by a film layer patterning process.

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