Self-cleaning optical filter with bionic micro-nano structure, security lens and laser radar

Abstract

The invention discloses a self-cleaning optical filter of a bionic micro-nano structure, a security lens and a laser radar, the self-cleaning optical filter of the bionic micro-nano structure comprises an optical filter body, a plurality of micron-sized lotus leaf mastoid structures are formed on the optical filter body, a nano-sized moth-eye array structure is formed on each micron-sized lotus leaf mastoid structure, and the nano-sized moth-eye array structure is formed on the optical filter body. And the plurality of micron-sized lotus leaf mastoid structures and the plurality of nano-sized moth eye array structures are positioned on the outermost layer of the optical filter body. Therefore, the light transmittance of the optical filter is improved, light reflection is reduced, the optical filter has a self-cleaning function, the transmittance is prevented from being reduced after pollutants adhere to the surface of the optical filter, the normal function of an optical system is ensured, and performance degradation caused by aging of the functional coating is avoided. And the negative influence on the optical performance of the optical filter after the functional coating is aged can be avoided.

Description

Technical Field

[0001] This invention relates to the field of filter technology, and more specifically, to a biomimetic micro / nano structure self-cleaning filter, security lens, and lidar. Background Technology

[0002] Security surveillance cameras, automotive LiDAR, and military optical devices all require optical filters. Since these filters are located on the outermost layer, they are almost always exposed to complex outdoor environments. If contaminants (such as dust, water stains, or oil) adhere to the surface of these optical lenses, it will directly lead to decreased system transmittance, reduced signal-to-noise ratio, or poor image quality, and may even cause misjudgments, affecting the normal function of the optical system. Currently, there are generally two solutions to this problem: Passive cleaning: Regularly wiping or cleaning the surface with detergent. This method is not only inefficient and costly, but also sometimes difficult to operate, such as high-altitude surveillance cameras.

[0003] II. Applying hydrophobic and oleophobic functional coatings: An AF (anti-fingerprint film) coating is applied to the filter surface. However, AF coatings are organic materials. While they may be effective initially, long-term exposure to harsh conditions such as outdoor UV radiation, acid rain, and temperature fluctuations can cause organic materials to age, leading to performance degradation and even affecting their anti-fouling function. More importantly, damaged organic coatings may introduce new interfaces, increasing surface reflection and scattering, negatively impacting the optical performance of the filter. Summary of the Invention

[0004] The technical problem to be solved by this invention is how to improve the light transmittance of the filter, reduce light reflection, and enable the filter to have a self-cleaning function, so as to avoid the filter surface from being contaminated and reducing the transmittance, ensuring the normal function of the optical system, and preventing the performance from deteriorating due to the aging of the functional coating, and further avoiding the negative impact of the aging of the functional coating on the optical performance of the filter.

[0005] The technical problem to be solved by the present invention is achieved through the following technical solution: To address the aforementioned technical problems, this invention provides a biomimetic micro / nano structure self-cleaning filter, comprising a filter body, on which multiple micron-sized lotus leaf papillae structures are formed, and on each micron-sized lotus leaf papillae structure a nano-sized moth-eye array structure is formed, with the multiple micron-sized lotus leaf papillae structures and nano-sized moth-eye array structures located on the outermost layer of the filter body.

[0006] As a preferred embodiment of the biomimetic micro / nano structure self-cleaning filter provided by the present invention, the filter body is a multilayered dielectric film that is alternately stacked.

[0007] As a preferred embodiment of the self-cleaning filter with the biomimetic micro / nano structure provided by the present invention, the micron-scale lotus leaf papilla structure is a micron-scale protrusion or fold structure.

[0008] As a preferred embodiment of the biomimetic micro / nano structure self-cleaning filter provided by the present invention, the nanoscale moth-eye array structure is a structural array formed by multiple nanoscale cone structures or multiple nanoscale pillar structures.

[0009] In a preferred embodiment of the biomimetic micro / nano structure self-cleaning filter provided by the present invention, the sum of the heights of the micron-scale lotus leaf papilla structure and the nano-scale moth eye array structure is 0.3 μm-1 μm.

[0010] In a preferred embodiment of the self-cleaning filter with the biomimetic micro / nano structure provided by the present invention, the distance between the centers of two adjacent cone or column structures is 100nm-300nm.

[0011] As a preferred embodiment of the self-cleaning filter with the biomimetic micro / nano structure provided by the present invention, a plurality of the micron-scale lotus leaf papilla structures and nano-scale moth eye array structures are formed by an etching process.

[0012] As a preferred embodiment of the biomimetic micro / nano structure self-cleaning filter provided by the present invention, multiple micron-scale lotus leaf papilla structures and nano-scale moth eye array structures are formed by dry etching or wet etching processes.

[0013] The present invention provides a security lens comprising a self-cleaning filter with a biomimetic micro / nano structure as described in any of the preceding claims.

[0014] The present invention provides a lidar comprising a self-cleaning filter with a biomimetic micro / nano structure as described in any of the preceding claims.

[0015] The present invention has the following beneficial effects: The lotus leaf-shaped papillary structure of this invention consists of micron-sized papillary protrusions, forming a multi-level rough structure resembling small hills to create a superhydrophobic effect. An air film forms on the surface, preventing water droplets from spreading, resulting in a contact angle exceeding 150°. This relies primarily on surface tension and the air cushion effect. Water droplets roll spherically on the surface of the lotus leaf-shaped papillary structure, easily carrying away dust and contaminants, achieving anti-fouling, waterproof, and self-cleaning surface functions.

[0016] The optical principle of the moth-eye structure of this invention is the gradient refractive index effect. According to Fresnel's equations, light is reflected when passing through an interface between media with different refractive indices. When the interface is an ideal, smooth transition much smaller than the wavelength of the incident light, reflection can be minimized. The biomimetic micro / nano structure (moth-eye structure) of this invention is equivalent to forming a continuously gradient transition layer between the substrate surface and air, where the refractive index changes from the substrate material (refractive index approximately 1.5) to air (refractive index approximately 1.0). This is a non-abrupt interface with almost no loss of reflectivity, thus minimizing reflection.

[0017] By setting a biomimetic physical structure on the outermost layer of the filter body that combines ultra-low reflection with "moth eye structure" and self-cleaning function with "lotus leaf effect", the filter can simultaneously achieve broadband high transmittance (transmittance > 98%) and ultra-strong self-cleaning function (water droplet angle > 150°, slip angle < 10°). As the outermost layer of the filter, the biomimetic physical structure does not affect the interference film system inside.

[0018] This improves the light transmittance of the filter, reduces light reflection, and enables the filter to have a self-cleaning function. It prevents contaminants from adhering to the filter surface and reducing transmittance, ensuring the normal function of the optical system. Furthermore, it prevents performance degradation due to the aging of the functional coating and avoids negative impacts on the optical performance of the filter after the functional coating ages. Attached Figure Description

[0019] To more clearly illustrate the solutions in this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a biomimetic micro / nano structure self-cleaning filter provided by the present invention.

[0021] Explanation of icon numbers: Filter body 1; micron-scale lotus leaf papilla structure 2; nano-scale moth eye array structure 3. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0025] The present invention provides a biomimetic micro-nano structure self-cleaning filter, which includes a filter body, on which multiple micron-sized lotus leaf papillae structures are formed, and on each micron-sized lotus leaf papillae structure a nano-sized moth eye array structure is formed, and the multiple micron-sized lotus leaf papillae structures and nano-sized moth eye array structures are all located on the outermost layer of the filter body.

[0026] The lotus leaf-shaped papillary structure of this invention consists of micron-sized papillary protrusions, forming a multi-level rough structure resembling small hills to create a superhydrophobic effect. An air film forms on the surface, preventing water droplets from spreading, resulting in a contact angle exceeding 150°. This relies primarily on surface tension and the air cushion effect. Water droplets roll spherically on the surface of the lotus leaf-shaped papillary structure, easily carrying away dust and contaminants, achieving anti-fouling, waterproof, and self-cleaning surface functions.

[0027] The optical principle of the moth-eye structure of this invention is the gradient refractive index effect. According to Fresnel's equations, light is reflected when passing through an interface between media with different refractive indices. When the interface is an ideal, smooth transition much smaller than the wavelength of the incident light, reflection can be minimized. The biomimetic micro / nano structure (moth-eye structure) of this invention is equivalent to forming a continuously gradient transition layer between the substrate surface and air, where the refractive index changes from the substrate material (refractive index approximately 1.5) to air (refractive index approximately 1.0). This is a non-abrupt interface with almost no loss of reflectivity, thus minimizing reflection.

[0028] By setting a biomimetic physical structure on the outermost layer of the filter body that combines ultra-low reflection with "moth eye structure" and self-cleaning function with "lotus leaf effect", the filter can simultaneously achieve broadband high transmittance (transmittance > 98%) and ultra-strong self-cleaning function (water droplet angle > 150°, slip angle < 10°). As the outermost layer of the filter, the biomimetic physical structure does not affect the interference film system inside.

[0029] This improves the light transmittance of the filter, reduces light reflection, and enables the filter to have a self-cleaning function. It prevents contaminants from adhering to the filter surface and reducing transmittance, ensuring the normal function of the optical system. Furthermore, it prevents performance degradation due to the aging of the functional coating and avoids negative impacts on the optical performance of the filter after the functional coating ages.

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. The present invention will be described in detail below with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0031] Please see Figure 1 The present invention provides a biomimetic micro-nano structure self-cleaning filter, which includes a filter body 1, on which a plurality of micron-sized lotus leaf papillae structures 2 are formed, and on each micron-sized lotus leaf papillae structure 2 a nano-sized moth eye array structure 3 is formed, and the plurality of micron-sized lotus leaf papillae structures 2 and the nano-sized moth eye array structure 3 are all located on the outermost layer of the filter body 1.

[0032] The lotus leaf-shaped papillary structure of this invention consists of micron-sized papillary protrusions, forming a multi-level rough structure resembling small hills to create a superhydrophobic effect. An air film forms on the surface, preventing water droplets from spreading, resulting in a contact angle exceeding 150°. This relies primarily on surface tension and the air cushion effect. Water droplets roll spherically on the surface of the lotus leaf-shaped papillary structure, easily carrying away dust and contaminants, achieving anti-fouling, waterproof, and self-cleaning surface functions.

[0033] The optical principle of the moth-eye structure of this invention is the gradient refractive index effect. According to Fresnel's equations, light is reflected when passing through an interface between media with different refractive indices. When the interface is an ideal, smooth transition much smaller than the wavelength of the incident light, reflection can be minimized. The biomimetic micro / nano structure (moth-eye structure) of this invention is equivalent to forming a continuously gradient transition layer between the substrate surface and air, where the refractive index changes from the substrate material (refractive index approximately 1.5) to air (refractive index approximately 1.0). This is a non-abrupt interface with almost no loss of reflectivity, thus minimizing reflection.

[0034] By setting a biomimetic physical structure with both "moth eye structure" ultra-low reflection and "lotus leaf effect" self-cleaning function on the outermost layer of the filter body 1, the filter can simultaneously achieve broadband high transmittance (transmittance > 98%) and super self-cleaning function (water droplet angle > 150°, slip angle < 10°). As the outermost layer of the filter, the biomimetic physical structure does not affect the interference film system inside.

[0035] This improves the light transmittance of the filter, reduces light reflection, and enables the filter to have a self-cleaning function. It prevents contaminants from adhering to the filter surface and reducing transmittance, ensuring the normal function of the optical system. Furthermore, it prevents performance degradation due to the aging of the functional coating and avoids negative impacts on the optical performance of the filter after the functional coating ages.

[0036] Furthermore, the filter body 1 is a dielectric film with multiple layers alternately stacked.

[0037] Furthermore, the micron-scale lotus leaf papilla structure 2 is a micron-scale protrusion or fold structure, and the nano-scale moth-eye array structure 3 is composed of nano-scale protrusions or depressions (such as cones, cylinders, and parabolas). The structural period is smaller than the wavelength of visible light, forming a dense array similar to a "honeycomb" to create a gradient refractive index effect. The structural scale is smaller than the wavelength of light, making the light "indistinguishable" from the microstructure, resulting in a continuous change in refractive index along the depth direction, thereby greatly reducing light reflection. This mainly relies on optical interference and diffraction. In this embodiment, the nano-scale moth-eye array structure 3 is a structural array formed by multiple nano-scale cone structures or multiple nano-scale pillar structures. These structures can be formed by an etching process, which can be dry etching or wet etching.

[0038] Furthermore, the sum of the heights of the micron-scale lotus leaf papilla structure 2 and the nano-scale moth eye array structure 3 is 0.3μm-1μm, and the distance between the centers of two adjacent cone structures or column structures is 100nm-300nm.

[0039] Specifically, a multilayer dielectric film consisting of alternating layers of low-refractive-index materials (such as SiO2) and high-refractive-index materials (such as Nb2O5) can be deposited on a glass substrate by magnetron sputtering, and then etched on the multilayer dielectric film to form a micron-scale lotus leaf papilla structure 2 and a nano-scale moth eye array structure 3.

[0040] The present invention provides a security lens comprising a self-cleaning filter with a biomimetic micro / nano structure as described in any of the preceding claims.

[0041] The present invention provides a lidar comprising a self-cleaning filter with a biomimetic micro / nano structure as described in any of the preceding claims.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] Obviously, the embodiments described above are only some embodiments of this application, not all embodiments. The accompanying drawings show preferred embodiments of this application, but do not limit the patent scope of this application. This application can be implemented in many different forms; rather, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this application's specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the scope of patent protection of this application.

Claims

1. A biomimetic micro / nano structure self-cleaning filter, characterized in that, It includes a filter body, on which multiple micron-sized lotus leaf papillae structures are formed, and on each micron-sized lotus leaf papillae structure a nano-sized moth eye array structure is formed, and the multiple micron-sized lotus leaf papillae structures and nano-sized moth eye array structures are all located on the outermost layer of the filter body.

2. The biomimetic micro / nano structure self-cleaning filter according to claim 1, characterized in that, The filter body is a multi-layered dielectric film.

3. The biomimetic micro / nano structure self-cleaning filter according to claim 1, characterized in that, The micron-scale lotus leaf papillae structure is a micron-scale protrusion or fold structure.

4. The biomimetic micro / nano structure self-cleaning filter according to claim 1, characterized in that, The nanoscale moth-eye array structure is a structural array formed by multiple nanoscale cone structures or multiple nanoscale pillar structures.

5. The biomimetic micro / nano structure self-cleaning filter according to claim 1, characterized in that, The sum of the heights of the micron-scale lotus leaf papillae structure and the nano-scale moth eye array structure is 0.3μm-1μm.

6. The biomimetic micro / nano structure self-cleaning filter according to claim 4, characterized in that, The distance between the centers of two adjacent cone or column structures is 100nm-300nm.

7. The biomimetic micro / nano structure self-cleaning filter according to claim 1, characterized in that, Multiple micron-scale lotus leaf papillae structures and nano-scale moth eye array structures are formed by an etching process.

8. The biomimetic micro / nano structure self-cleaning filter according to claim 7, characterized in that, Multiple micron-scale lotus leaf papillae structures and nano-scale moth eye array structures are formed by dry etching or wet etching processes.

9. A security camera lens, characterized in that, It includes a self-cleaning filter with a biomimetic micro / nano structure as described in any one of claims 1-8.

10. A lidar, characterized in that, It includes a self-cleaning filter with a biomimetic micro / nano structure as described in any one of claims 1-8.

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