Infrared band pixel-level dual-channel optical filter and preparation method thereof

Abstract

The invention relates to the technical field of optical thin films, and particularly provides an infrared band pixel-level dual-channel optical filter and a preparation method thereof. The infrared band pixel-level dual-channel optical filter comprises a substrate, a dual-bandpass filtering film stack structure arranged on the first surface of the substrate, and short bandpass filtering film stacks and long bandpass filtering film stacks which are arranged on the second surface of the substrate in an array manner, the short band-pass filtering film stack and the first surface double-band-pass filtering film stack form a short band-pass spectrum channel, and the long band-pass filtering film stack and the first surface double-band-pass filtering film stack form a long band-pass spectrum channel. According to the invention, a transition area between two channels at an infrared band pixel level is reduced, and spectral crosstalk is reduced, so that the imaging quality is improved; according to the preparation method of the infrared band pixel-level dual-channel optical filter, on the basis of ensuring good spectral characteristics, the thickness of a filter film stack deposited in a patterned spectral channel region is reduced, a transition region between infrared band pixel-level dual channels can be greatly reduced, and spectral crosstalk is reduced, so that the imaging quality is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of optical films, and in particular relates to an infrared band pixel-level dual-channel filter and a preparation method thereof. Background Art

[0002] Infrared imaging technology has been widely used in civil and military fields such as online power detection, environmental monitoring, missile warning, and infrared reconnaissance. In order to improve the signal-to-noise ratio of infrared detectors, specific filters are usually inserted into the optical system to suppress stray light outside the working band to improve the target recognition ability of infrared detectors. In order to further improve the recognition ability of the detector and simplify the structure of the camera optical system, dual-channel or more-channel spectral filters are often required. Integrating them on the surface of the detector chip can simultaneously output target information of multiple spectral channels, which is more conducive to target recognition.

[0003] There are two types of dual-channel spectral filters. One is that the spectral channels are linearly arranged in one dimension. When integrated in the detector, it is only suitable for push-scan imaging and has difficulty capturing fast-moving targets. The other is a pixel-level dual-channel filter. Its spectral channels are a mosaic array structure in two dimensions. The spectral channel size is at the pixel level and can correspond one-to-one with the pixels on the detector chip. When integrated on the surface of the detector chip, it can achieve snapshot spectral imaging and has the ability to capture dynamic targets.

[0004] Bandpass filters with good spectral characteristics working in the infrared band, especially the mid-wave infrared band, usually have a physical thickness of more than 10μm, while the pixel size of infrared band detector chips is generally 20μm or even smaller. In the process of preparing the mid-wave infrared band pixel-level dual-channel filter, when the second pixel-level spectral channel is prepared on the basis of the first pixel-level spectral channel, the thin film deposition shadow shielding effect caused by the thicker physical thickness of the first spectral channel makes it impossible to deposit optical thin films in the intersection area of ​​the two spectral channels, resulting in a wide transition zone between the infrared band pixel-level dual channels and serious spectral crosstalk. Therefore, it is urgent to study a preparation method for infrared band pixel-level dual-channel filters to reduce the transition zone between the pixel-level dual channels, reduce spectral crosstalk and improve imaging quality. Summary of the invention

[0005] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0006] The present invention provides an infrared band pixel-level dual-channel filter, comprising a substrate, wherein the substrate has a first surface and a second surface opposite to the first surface, a dual-bandpass filter film stack is arranged on the first surface, a short-bandpass filter film stack and a long-bandpass filter film stack are alternately arranged on the second surface, the short-bandpass filter film stack and the long-bandpass filter film stack are both periodically arranged square unit structures, each square unit structure corresponds to a pixel on the surface of a detector chip, the short-bandpass filter film stack on the second surface and the dual-bandpass filter film stack on the first surface constitute a short-bandpass spectral channel, and the long-bandpass filter film stack on the second surface and the dual-bandpass filter film stack on the first surface constitute a long-bandpass spectral channel.

[0007] Preferably, the dual-pass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 10 μm to 20 μm.

[0008] Preferably, the short-bandpass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm; the long-bandpass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm.

[0009] The present invention also provides a method for preparing an infrared band pixel-level dual-channel filter, comprising the following steps:

[0010] S1: Use film system design software to design the structure of the dual-bandpass filter film stack. The two passband center wavelengths are designed to be 3.7μm~4μm and 4.55μm~4.8μm respectively. The average transmittance of the passband is greater than 95%, and the average transmittance of the stopband is less than 1%;

[0011] S2: Clean the substrate, and coat the dual-bandpass filter stack designed in step S1 on the first surface of the substrate using a thin film preparation process, wherein the total thickness of the dual-bandpass filter stack is 10 μm to 20 μm;

[0012] S3: Use film system design software to design the structure of the short-bandpass filter film stack. The passband center wavelength of the short-bandpass filter film stack is 3.7μm~4μm, and the average transmittance is greater than 95%. The stopband center wavelength of the short-bandpass filter film stack is 4.4μm~5μm, and the average transmittance is less than 1%;

[0013] S4: depositing a negative photoresist on the second surface of the substrate, performing pre-baking on a hot plate, preparing a first mask, covering the first mask on the second surface of the substrate, aligning and exposing, removing the first mask, performing post-baking on a hot plate, and then removing the negative photoresist corresponding to the first light-shielding area by developing, the exposed area being a first spectral channel area, including periodically arranged first spectral channel units, each of which corresponds one-to-one to a pixel of a detector chip;

[0014] S5: using a thin film preparation process to coat the short-bandpass filter film stack designed in step S3 on the second surface, with a total thickness of 1 μm to 6 μm, and then using a chemical solution to remove the negative photoresist outside the first spectral channel region and the short-bandpass filter film stack deposited on the negative photoresist to form a periodically arranged short-bandpass filter film stack, wherein the periodically arranged short-bandpass filter film stack and the dual-bandpass filter film stack on the first surface together constitute a short-bandpass spectral channel, and its spectrum exhibits a short-bandpass characteristic;

[0015] S6: Use film system design software to design the structure of the long-bandpass filter film stack. The passband center wavelength of the long-bandpass filter film stack is 4.55μm~4.8μm, and the average transmittance is greater than 95%. The stopband center wavelength of the long-bandpass filter film stack is 3.5μm~4.2μm, and the average transmittance is less than 0.4%;

[0016] S7: preparing a second mask, placing the second mask in close contact with the second surface of the sapphire substrate after step S5, depositing negative photoresist on the second surface in close contact with the second mask, front-baking using a hot plate, aligning exposure, and back-baking the exposed substrate using a hot plate again, and then removing the second mask, the surface of the short-bandpass filter film stack on the second surface is correspondingly covered with a layer of negative photoresist, and the exposed area of ​​the second surface is the second spectral channel area, including periodically arranged second spectral channel units, and each second spectral channel unit corresponds to a pixel on the surface of the detector chip one by one;

[0017] S8: Repeat step S5, and coat the long-bandpass filter film stack designed in step S6 in the second spectral channel region with a total thickness of 1μm to 6μm, and then use a chemical solution to remove the negative photoresist outside the second spectral channel region and the long-bandpass filter film stack deposited on the negative photoresist. The retained long-bandpass filter film stack and the dual-bandpass filter film stack on the first surface together constitute a long-bandpass spectral channel, and its spectrum exhibits a long-bandpass characteristic.

[0018] Preferably, the thin film preparation process in step S2 includes an ion beam assisted electron beam evaporation process or a magnetron sputtering process or an ion beam sputtering process or a plasma enhanced chemical vapor deposition process.

[0019] Preferably, the dual-pass filter film stack in S2 is composed of alternating high-refractive index material films and low-refractive index material films; the short-bandpass filter film stack in S5 is composed of alternating high-refractive index material films and low-refractive index material films; the long-bandpass filter film stack in S8 is composed of alternating high-refractive index material films and low-refractive index material films.

[0020] Preferably, the first mask in S4 includes a frame and a first working area therein, the first working area includes a first light-transmitting area and a first light-shielding area, and the second surface corresponding to the first light-shielding area is an unexposed area; the second mask in S7 includes a frame and a second working area therein, the second working area includes a second light-transmitting area and a second light-shielding area, the second light-transmitting area corresponds to the first light-shielding area, and the second light-shielding area corresponds to the first light-transmitting area.

[0021] Compared with the prior art, the invention can achieve the following beneficial effects:

[0022] The invention creates the infrared band pixel-level dual-channel filter, which greatly reduces the transition zone between the infrared band pixel-level dual channels, reduces spectral crosstalk and thus improves imaging quality. The invention creates the infrared band pixel-level dual-channel filter preparation method, which reduces the thickness of the filter film stack deposited in the patterned spectral channel region on the basis of ensuring good spectral characteristics, can greatly reduce the transition zone between the infrared band pixel-level dual channels, reduce spectral crosstalk and thus improve imaging quality, and improve production efficiency and yield, ensuring the quality of the prepared infrared band pixel-level dual-channel filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0024] Figure 1 It is a schematic diagram of the infrared band pixel-level dual-channel filter of the present invention;

[0025] Figure 2 It is a schematic diagram of the second surface of the infrared band pixel-level dual-channel filter of the present invention;

[0026] Figure 3 It is a schematic diagram of the preparation process of the infrared band pixel-level dual-channel filter of the present invention;

[0027] Figure 4 It is the transmittance characteristic curve of the dual-band channel filter film stack;

[0028] Figure 5 It is the transmittance characteristic curve of the short-band channel filter film stack;

[0029] Figure 6 It is the transmittance characteristic curve of the long-band channel filter film stack.

[0030] Reference numerals:

[0031] 1. Substrate; 11. First surface; 12. Second surface; 2. Dual-bandpass filter stack; 3. Short-bandpass filter stack; 4. Long-bandpass filter stack; 5. Negative photoresist. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0034] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0035] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0036] Embodiment 1

[0037] like Figure 1 to Figure 3The figure shows a schematic diagram of an infrared band pixel-level dual-channel filter of the present invention, comprising a substrate 1, wherein the substrate 1 has a first surface 11 and a second surface 12 opposite to the first surface 11, a dual-bandpass filter film stack 2 is arranged on the first surface 11, and the dual-bandpass filter film stack 2 is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 10μm to 20μm; a short-bandpass filter film stack 3 and a long-bandpass filter film stack 4 are arranged in an alternating array on the second surface 12, and the short-bandpass filter film stack 3 and the long-bandpass filter film stack 4 are both periodically arranged square unit structures, each square unit structure corresponds to a pixel on the surface of the detector chip, the short-bandpass filter film stack 3 on the second surface 12 and the dual-bandpass filter film stack 2 on the first surface 11 constitute a short-bandpass spectral channel, and the long-bandpass filter film stack 4 on the second surface 12 and the dual-bandpass filter film stack 2 on the first surface 11 constitute a long-bandpass spectral channel.

[0038] Specifically, the short-bandpass filter film stack 3 is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm; the long-bandpass filter film stack 4 is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm.

[0039] Embodiment 2

[0040] like Figure 3 The figure shows a schematic diagram of the preparation process of the infrared band pixel-level dual-channel filter of the present invention, and the specific working steps are as follows:

[0041] S1: Macleod film system design software is used to design a dual-bandpass filter film stack structure with a working band from 3.5μm to 5μm. The substrate 1 material used in the design is sapphire material. The film stack structure is composed of a high-refractive index Ge film and a low-refractive index ZnS film. The total number of film layers is 34, and the thickness of the film stack structure is 13.5μm. The spectral curve of the dual-bandpass filter film stack structure is as follows: Figure 4 As shown in the figure, the designed dual-bandpass filter stack has the characteristic of being able to transmit two spectral passbands. The central wavelengths of these two spectral passbands are 3.7-4μm and 4.55-4.8μm, respectively. The average transmittance is 99%, the average transmittance of the stopband is 0.8%, and the average width of the transition region from the passband to the stopband is 57nm, that is, Figure 4 The width between the transmittance 90% position and the transmittance 10% position.

[0042] S2: The dual-bandpass filter film stack structure designed in step S1 is plated on the first surface 11 of the clean sapphire substrate 1 by using an ion beam assisted electron beam evaporation process. The vacuum degree during the deposition of the film is higher than 1×10 -2 Pa, Ge thin film and ZnS thin film are deposited alternately, and the deposition rate of Ge thin film is The deposition rate of ZnS film is The total thickness of the deposited film is 10 μm to 20 μm.

[0043] S3: Macleod film system design software is used to design a short-bandpass filter film stack structure. The substrate 1 material used in the design is sapphire material. The film stack structure is composed of a high-refractive-index Ge film and a low-refractive-index SiO2 film. The total number of film layers is 7, and the thickness of the film stack structure is 4.3μm. The spectral curve is as follows: Figure 5 As shown, the central wavelength of the spectral passband of the short-bandpass filter film stack structure is 3.7μm~4μm, and its average transmittance is 99%, and the central wavelength of the spectral stopband is 4.4μm~5μm, and its average transmittance is 0.6%.

[0044] S4: Spin-coat SU-8 negative photoresist on the second surface of the cleaned substrate 1 at a rotation speed of 2500 rpm and a thickness of 5 μm, and pre-bake at 100° C. for 3 minutes using a hot plate. A graphic first mask is prepared, the graphic first mask includes a frame and a first working area inside it, the first working area is an array of periodically arranged square unit structures, each square unit structure corresponds one-to-one to a pixel on the surface of the detector chip, the first working area includes a first light-transmitting area and a first light-shielding area, the first light-transmitting area includes a plurality of square unit structures, and the first light-shielding area covers the remaining square unit structures, the first mask is placed close to the second surface 12 of the sapphire substrate 1, aligned for exposure, the exposure time is 3 seconds, the first mask is removed, and the exposed substrate 1 is post-baked at 100° C. for 3 minutes using a hot plate again, and then developed in a developer for 3 minutes, the negative photoresist corresponding to the first light-shielding area is removed, and the exposed area is the first area, including periodically arranged first units, each of which has a size of 20 μm×20 μm, which corresponds one-to-one to the pixel on the surface of the detector chip, and the negative photoresist corresponding to the first light-transmitting area forms a periodically arranged square unit structure on the second surface 12.

[0045] S5: Using an ion beam assisted electron beam evaporation process, the short-bandpass filter film stack structure designed in step S3 is plated on the patterned second surface 12, and the thickness of the short-bandpass filter film stack structure is 4.3 μm. Then, the processed substrate 1 is immersed in a degumming solution for boiling to remove the negative photoresist and the short-bandpass filter film stack structure plated thereon. The retained short-bandpass filter film stack and the dual-bandpass filter film stack on the first surface 11 together constitute a short-bandpass spectral channel, and its spectrum exhibits a short-bandpass characteristic.

[0046] S6: Use film system design software to design the structure of the long-bandpass filter film stack. The substrate 1 is sapphire. The long-bandpass filter film stack is composed of a Ge film of a high refractive index material and a SiO2 film of a low refractive index material. The total number of film layers is 11. The thickness of the film stack structure is 3.3μm. The passband center wavelength is 4.55μm~4.8μm, and its average transmittance is better than 99%. The stopband center wavelength is 3.5μm~4.2μm, and its average transmittance is 0.4%. The spectral curve is as follows Figure 6 shown.

[0047] S7: Spin-coat SU-8 type negative photoresist on the second surface 12, and pre-bake it at 100°C for 3 minutes using a hot plate. Prepare a second mask, the second mask includes a frame and a second working area inside it, the second working area is a square unit structure arranged periodically in an array, each square unit structure corresponds to a pixel on the surface of the detector chip one by one, the second working area includes a second light-transmitting area and a second light-shielding area, the second light-transmitting area corresponds to the first light-shielding area in step S4, the second light-shielding area corresponds to the first light-transmitting area in step S4, the second mask is placed close to the second surface 12 of the substrate 1, aligned for exposure, the exposure time is 3 seconds, the second mask is removed, and the exposed substrate 1 is post-baked at 100° C. for 3 minutes using a hot plate again, and then developed in a developer for 3 minutes, the negative photoresist corresponding to the second light-shielding area is removed, the surface of the short-bandpass filter film stack 3 of the second surface 12 is correspondingly covered with a layer of negative photoresist, the exposed area of ​​the second surface 12 is the second area, including periodically arranged second units, each second unit has a size of 20 μm×20 μm, and corresponds to the pixel on the surface of the detector chip one by one.

[0048] S8: Repeat step S5, and coat the long-bandpass filter film stack structure designed in step S6 on the second surface, wherein the thickness of the long-bandpass filter film stack structure is 3.3 μm, and then immerse the processed substrate 1 in a degumming solution for boiling to remove the negative photoresist and the long-bandpass filter film stack structure coated thereon, and the retained long-bandpass filter film stack 4 and the dual-bandpass filter film stack 2 on the first surface 11 together constitute a long-bandpass spectral channel, and its spectrum exhibits a long-bandpass characteristic.

[0049] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An infrared band pixel-level dual-channel filter, characterized in that: include: A substrate, wherein the substrate has a first surface and a second surface opposite to the first surface, a dual-bandpass filter film stack is arranged on the first surface, a short-bandpass filter film stack and a long-bandpass filter film stack are arranged in an array on the second surface, the short-bandpass filter film stack and the long-bandpass filter film stack are both periodically arranged square unit structures, each square unit structure corresponds to a pixel on the surface of the detector chip, the short-bandpass filter film stack on the second surface and the dual-bandpass filter film stack on the first surface constitute a short-bandpass spectral channel, and the long-bandpass filter film stack on the second surface and the dual-bandpass filter film stack on the first surface constitute a long-bandpass spectral channel.

2. The infrared band pixel-level dual-channel filter according to claim 1, characterized in that: The double-pass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 10 μm to 20 μm.

3. The infrared band pixel-level dual-channel filter according to claim 1, characterized in that: The short-bandpass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm; the long-bandpass filter film stack is composed of alternating high-refractive index material films and low-refractive index material films, with a total thickness of 1μm to 6μm.

4. A method for preparing the infrared band pixel-level dual-channel filter according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1: Use film system design software to design the structure of the dual-bandpass filter film stack. The two passband center wavelengths are designed to be 3.7μm~4μm and 4.55μm~4.8μm respectively. The average transmittance of the passband is greater than 95%, and the average transmittance of the stopband is less than 1%; S2: Clean the substrate, and coat the dual-bandpass filter stack designed in step S1 on the first surface of the substrate using a thin film preparation process, wherein the total thickness of the dual-bandpass filter stack is 10 μm to 20 μm; S3: Use film system design software to design the structure of the short-bandpass filter film stack. The passband center wavelength of the short-bandpass filter film stack is 3.7μm~4μm, and the average transmittance is greater than 95%. The stopband center wavelength of the short-bandpass filter film stack is 4.4μm~5μm, and the average transmittance is less than 1%; S4: depositing a negative photoresist on the second surface of the substrate, performing pre-baking on a hot plate, preparing a first mask, covering the first mask on the second surface of the substrate, aligning and exposing, removing the first mask, performing post-baking on a hot plate, and then removing the negative photoresist in the unexposed area by developing, the exposed area being a first spectral channel area, including periodically arranged first spectral channel units, each of which corresponds to a pixel of the detector chip one by one; S5: using a thin film preparation process to coat the short-bandpass filter film stack designed in step S3 on the second surface, with a total thickness of 1 μm to 6 μm, and then using a chemical solution to remove the negative photoresist outside the first spectral channel region and the short-bandpass filter film stack deposited on the negative photoresist to form a periodically arranged short-bandpass filter film stack, wherein the periodically arranged short-bandpass filter film stack and the dual-bandpass filter film stack on the first surface together constitute a short-bandpass spectral channel, and its spectrum exhibits a short-bandpass characteristic; S6: Use film system design software to design the structure of the long-bandpass filter film stack. The passband center wavelength of the long-bandpass filter film stack is 4.55μm~4.8μm, and the average transmittance is greater than 95%. The stopband center wavelength of the long-bandpass filter film stack is 3.5μm~4.2μm, and the average transmittance is less than 0.4%; S7: preparing a second mask, placing the second mask in close contact with the second surface of the substrate after step S5, depositing negative photoresist on the second surface in close contact with the second mask, front-baking using a hot plate, aligning exposure, and back-baking the exposed substrate using a hot plate again, and then removing the second mask, the surface of the short-bandpass filter film stack on the second surface is correspondingly covered with a layer of negative photoresist, and the exposed area of ​​the second surface is the second spectral channel area, including periodically arranged second spectral channel units, and each second spectral channel unit corresponds to a pixel on the surface of the detector chip one by one; S8: Repeat step S5, and coat the long-bandpass filter film stack designed in step S6 in the second spectral channel region with a total thickness of 1μm to 6μm, and then use a chemical solution to remove the negative photoresist outside the second spectral channel region and the long-bandpass filter film stack deposited on the negative photoresist. The retained long-bandpass filter film stack and the dual-bandpass filter film stack on the first surface together constitute a long-bandpass spectral channel, and its spectrum exhibits a long-bandpass characteristic.

5. The method for preparing an infrared band pixel-level dual-channel filter according to claim 4, characterized in that: The thin film preparation process in S2 includes an ion beam assisted electron beam evaporation process, a magnetron sputtering process, an ion beam sputtering process or a plasma enhanced chemical vapor deposition process.

6. The method for preparing an infrared band pixel-level dual-channel filter according to claim 4, characterized in that: The double-pass filter film stack in S2 is composed of alternating high-refractive index material films and low-refractive index material films.

7. The method for preparing an infrared band pixel-level dual-channel filter according to claim 4, characterized in that: The short-bandpass filter film stack in S5 is composed of alternating high-refractive-index material films and low-refractive-index material films.

8. The method for preparing an infrared band pixel-level dual-channel filter according to claim 4, characterized in that: The long-bandpass filter film stack in S8 is composed of alternating high-refractive-index material films and low-refractive-index material films.

9. The method for preparing an infrared band pixel-level dual-channel filter according to claim 4, characterized in that: The first mask in S4 includes a frame and a first working area therein, the first working area includes a first light-transmitting area and a first light-shielding area, and the second surface corresponding to the first light-shielding area is an unexposed area.

10. The method for preparing an infrared band pixel-level dual-channel filter according to claim 9, characterized in that: The second mask in S7 includes a frame and a second working area therein, the second working area includes a second light-transmitting area and a second light-shielding area, the second light-transmitting area corresponds to the first light-shielding area, and the second light-shielding area corresponds to the first light-transmitting area.

Images