Low reflectance optical lens

Abstract

The utility model relates to a kind of low reflectivity optical lens, it includes optical substrate, grating structure being arranged in the structure area of the optical substrate, and moth eye film structure being arranged in the non-structure area of the optical substrate, the moth eye film structure includes multiple nanometer columns arranged in periodic array, the period P of the nanometer column does not exceed 300nm, and the cross-sectional area of the nanometer column decreases along the height direction.The utility model is designed moth eye film structure in lens non-structure area, while reducing production cost, realize low reflectivity in full visible light range.

Description

Technical Field

[0001] This utility model relates to the technical field of AR optical waveguides, and in particular to a low-reflectivity optical lens. Background Technology

[0002] Augmented Reality (AR) technology is an interactive method that overlays virtual information onto real-world scenes, and one of its core hardware components is AR glasses. AR glasses display virtual images through lens components, with a diffraction grating structure being a key optical element. This structure deflects the light from the projector and directs it directly to the user's eyes, achieving a fusion of virtual and real elements. Furthermore, to ensure a clear perception of the real-world scene, the lenses need high transmittance and low reflectance, approximating the appearance and performance of traditional nearsighted or farsighted lenses, while avoiding glare that could affect image quality. As optical performance requirements increase, the refractive index of the lens substrate material gradually increases, leading to a greater difference in refractive index between the lens and air, resulting in stronger reflections. This reflection not only reduces the lens's transmittance but also allows reflected light from the background to enter the eyes, severely impacting the wearer's visual experience. Therefore, effectively reducing the reflectance of high-refractive-index lenses without significantly increasing manufacturing costs has become a pressing technical challenge for the industry.

[0003] Currently, the mainstream approach to reducing lens reflectivity involves coating the unstructured areas of the diffraction grating and the non-grating surfaces of the lens with an anti-reflective coating (AR film). AR films are typically composed of two or more materials with different refractive indices stacked according to specific thickness rules, and are widely used in diffractive waveguide lenses to improve transmittance and reduce reflectivity. However, existing technologies have the following drawbacks: 1) Complex and costly processes: The AR film coating process requires numerous precision manufacturing processes, especially when dealing with grating surfaces. To prevent the film layer from covering the grating structure area, additional physical shielding measures are necessary, further increasing manufacturing difficulty and cost; 2) Strong angle dependence: AR films are usually designed for specific incident angles (e.g., normal incidence). When the light deviates from the designed angle, transmittance drops rapidly, and reflectivity increases accordingly, resulting in noticeable reflections at large angles, affecting the user experience. In summary, while existing technologies can reduce reflectivity to some extent, their high manufacturing costs and angle dependence limit their application effectiveness. Therefore, developing a technical solution that maintains low reflectivity over a wide angle range without significantly increasing manufacturing costs is a problem urgently needing to be solved by those skilled in the art. Utility Model Content

[0004] The problem this invention aims to solve is to provide a low-reflectivity optical lens that addresses the aforementioned shortcomings in the prior art. By finely designing the moth-eye membrane structure in the non-structural area of ​​the lens, it achieves low reflectivity across the entire visible light range while reducing production costs.

[0005] The above-mentioned objective of this utility model is achieved through the following technical solution: A low-reflectivity optical lens includes an optical substrate, a grating structure disposed in a structural region of the optical substrate, and a moth-eye membrane structure disposed in a non-structural region of the optical substrate. The moth-eye membrane structure includes a plurality of nanopillars arranged in a periodic array, wherein the period P of the nanopillars does not exceed 300 nm, and the cross-sectional area of ​​the nanopillars decreases along the height direction.

[0006] By adopting the above technical solution, the moth-eye membrane structure has the characteristics of large angle, wide wavelength and high transmittance. By controlling the period of its nanopillars to not exceed 300nm, it will not affect the beam transmission of the grating structure. Moreover, the overall structure of the nanopillars is searched along the height direction, thereby reducing the reflection phenomenon caused by the change in refractive index between the optical substrate and the air. Especially for optical substrates with high refractive index, the moth-eye membrane structure can effectively reduce the reflectivity of the non-structured area of ​​the optical lens, thereby reducing the overall reflection phenomenon of the optical lens. In addition, since the moth-eye membrane structure is also a periodic array and the overall structure is wide at the bottom and narrow at the top, the micro-nano fabrication of the grating structure and the moth-eye membrane structure can be carried out simultaneously to achieve the purpose of cost reduction and efficiency improvement. In summary, this low reflectivity optical lens not only effectively solves the problem of high reflectivity caused by the difference in refractive index in the prior art, but also achieves a low reflectivity effect with a wide angle and the entire visible light range through the innovative moth-eye membrane structure design, significantly improving the visual experience of optical devices such as AR glasses. Meanwhile, the simultaneous micro-nano fabrication process of the moth-eye membrane structure and the grating structure significantly reduces production costs and improves production efficiency, providing strong support for the commercial application of AR optical waveguide technology. In addition, this technical solution also has good adaptability and scalability. The parameters of the moth-eye membrane structure, such as the period, height and width of the nanopillars, can be flexibly adjusted according to different optical substrate materials and performance requirements to further optimize the reflectivity and optical performance of the lens. Therefore, the low-reflectivity optical lens proposed in this invention has broad application prospects and important practical value in the field of augmented reality technology.

[0007] The present invention is further configured such that the materials of the moth-eye membrane structure and the grating structure are optical glass, optical resin, diamond, silicon carbide, or gallium nitride.

[0008] By adopting the above technical solutions, materials such as optical glass, optical resin, diamond, silicon carbide, and gallium nitride have excellent optical properties and physical and chemical stability. Using these materials to make moth-eye film structures and grating structures can ensure that low-reflectivity optical lenses maintain stable performance in various complex environments. At the same time, it is also beneficial to improve the light transmittance of the lens and reduce the reflectivity, thereby further enhancing the visual experience of optical devices.

[0009] The present invention is further configured such that the material of the optical substrate is optical glass, optical resin, diamond, silicon carbide, or gallium nitride.

[0010] By adopting the above technical solutions, optical glass and optical resin have good light transmittance and formability, which can meet the basic requirements of optical lenses for light propagation and shape shaping; while materials such as diamond, silicon carbide, and gallium nitride have high hardness, high wear resistance and excellent optical performance, which can maintain the stability and reliability of the lens in complex use environments. Selecting these materials as optical substrates can ensure that low reflectivity optical lenses can perform at their best in different application scenarios.

[0011] The present invention is further configured such that the grating structure and the moth-eye membrane structure are integrally formed with the optical substrate.

[0012] By adopting the above technical solution, the grating structure and moth-eye film structure are integrally molded with the optical substrate. This integral molding process can greatly reduce interface reflection and scattering losses between structures, further improving the light transmittance of the lens and reducing its reflectivity. Moreover, the integral molding design makes the entire lens structure more compact and stable, avoiding problems such as loosening and misalignment that may occur due to the combination of different components. This greatly enhances the reliability and durability of the lens under various usage conditions, ensuring that the low-reflectivity optical lens can provide high-quality optical performance stably over a long period of time.

[0013] The present invention is further configured such that the grating structure and the moth-eye membrane structure are disposed on the optical substrate by coating or bonding.

[0014] By adopting the above technical solutions, the grating structure and the moth-eye film structure are deposited or bonded onto the optical substrate. The coating process can precisely deposit thin films with specific functions on the surface of the optical substrate to form the microstructure required for the grating structure and the moth-eye film structure, thereby effectively controlling the propagation path of light and reducing reflection. The bonding technology uses chemical or physical methods to tightly bond the grating structure and the moth-eye film structure to the optical substrate. This method not only ensures a strong connection between the grating structure and the moth-eye film structure and the optical substrate, but also allows for flexible adjustment of the parameters of the grating structure and the moth-eye film structure according to different application requirements while ensuring the overall optical performance of the lens, further improving the performance and adaptability of low-reflectivity optical lenses.

[0015] The present invention is further configured such that the period P of the nanopillar is 200~300nm.

[0016] By adopting the above technical solutions, the reflective characteristics and optical performance of the lenses can be further optimized.

[0017] The present invention is further configured such that the nanopillar is in the shape of a frustum or a pyramid.

[0018] By adopting the above technical solutions, the reflective characteristics and optical performance of the lenses can be further optimized.

[0019] The present invention is further configured such that the bottom width D1 of the nanopillar is 50~250nm.

[0020] By adopting the above technical solutions, the reflective characteristics and optical performance of the lenses can be further optimized.

[0021] The present invention is further configured such that the top surface width D2 of the nanopillar is 30~150nm.

[0022] By adopting the above technical solutions, the reflective characteristics and optical performance of the lenses can be further optimized.

[0023] The present invention is further configured such that the height H of the nanopillar is 100~500nm.

[0024] By adopting the above technical solutions, the reflective characteristics and optical performance of the lenses can be further optimized.

[0025] In summary, the beneficial technical effects of this invention are as follows: the low-reflectivity optical lens not only effectively solves the high reflectivity problem caused by refractive index differences in existing technologies, but also achieves a low-reflectivity effect across a wide angle and the entire visible light range through an innovative moth-eye membrane structure design, significantly improving the visual experience of optical devices such as AR glasses. Simultaneously, the synchronous micro-nano fabrication process of the moth-eye membrane structure and the grating structure greatly reduces production costs and improves production efficiency, providing strong support for the commercial application of AR waveguide technology. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the low-reflectivity optical lens of Embodiment 1 of this utility model.

[0027] Figure 2 This is a schematic diagram showing the connection relationship between the optical substrate and the moth-eye membrane structure in Embodiment 1 of this utility model.

[0028] Figure 3 This is a graph showing the transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 1 of this utility model as a function of wavelength.

[0029] Figure 4 This is a graph showing the change in transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 1 of this utility model as a function of the incident angle.

[0030] Figure 5 This is a graph showing the transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 2 of this utility model as a function of wavelength.

[0031] Figure 6 This is a graph showing the change in transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 2 of this utility model as a function of the incident angle.

[0032] Figure 7 This is a graph showing the transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 3 of this utility model as a function of wavelength.

[0033] Figure 8 This is a graph showing the change in transmittance of the unstructured region of the low-reflectivity optical lens of Embodiment 3 of this utility model as a function of the incident angle.

[0034] In the figure, 1 is the optical substrate; 2 is the grating structure; 3 is the moth-eye membrane structure; and 31 is the nanopillar. Detailed Implementation

[0035] To make the technical means, creative features, objectives and effects of this utility model clearer and easier to understand, the present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0036] Example 1: Refer to Figure 1This invention discloses a low-reflectivity optical lens, comprising an optical substrate 1, a grating structure 2 disposed in a structural region of the optical substrate 1, and a moth-eye membrane structure 3 disposed in a non-structural region of the optical substrate 1. (See reference...) Figure 2 The moth-eye membrane structure 3 includes multiple nanopillars 31 arranged in a periodic array. The period P of the nanopillars 31 does not exceed 300 nm, and the cross-sectional area of ​​the nanopillars 31 decreases along the height direction.

[0037] The moth-eye membrane structure 3 features a wide angle, broad wavelength, and high transmittance. By controlling the period of its nanopillars 31 to not exceed 300nm, it does not affect the beam transmission of the grating structure 2. Furthermore, the overall structure of the nanopillars 31 is aligned along the height direction, thereby reducing reflection caused by abrupt changes in refractive index between the optical substrate 1 and the air. Especially for high-refractive-index optical substrates 1, the moth-eye membrane structure 3 can effectively reduce the reflectivity of the non-structural areas of the optical lens, thus reducing the overall reflective phenomenon of the optical lens. In addition, since the moth-eye membrane structure 3 is also a periodic array with a bottom-wide and top-narrow overall structure, the micro-nano fabrication of the grating structure 2 and the moth-eye membrane structure 3 can be carried out simultaneously to achieve cost reduction and efficiency improvement. In summary, this low-reflectivity optical lens not only effectively solves the high reflectivity problem caused by refractive index differences in existing technologies, but also achieves a low-reflectivity effect across a wide angle and the entire visible light range through the innovative design of the moth-eye membrane structure 3, significantly improving the visual experience of optical devices such as AR glasses. Meanwhile, the synchronous micro-nano fabrication process of the moth-eye membrane structure 3 and the grating structure 2 significantly reduces production costs and improves production efficiency, providing strong support for the commercial application of AR optical waveguide technology. In addition, this technical solution also has good adaptability and scalability. The parameters of the moth-eye membrane structure 3, such as the period, height and width of the nanopillars 31, can be flexibly adjusted according to different optical substrate 1 materials and performance requirements to further optimize the reflectivity and optical performance of the lens. Therefore, the low-reflectivity optical lens proposed in this invention has broad application prospects and important practical value in the field of augmented reality technology.

[0038] Reference Figure 1 The optical substrate 1, the moth-eye film structure 3, and the grating structure 2 are each made of optical glass, optical resin, diamond, silicon carbide, or gallium nitride. Correspondingly, the grating structure 2 and the moth-eye film structure 3 are integrally formed with the optical substrate 1, or the grating structure 2 and the moth-eye film structure 3 are deposited or bonded onto the optical substrate 1.

[0039] Because optical glass, optical resin, diamond, silicon carbide, gallium nitride and other materials have excellent optical properties and physical and chemical stability, the selection of these materials to make the moth eye film structure 3 and grating structure 2 can ensure that the low reflectivity optical lens can maintain stable performance in various complex environments. At the same time, it is also beneficial to improve the light transmittance of the lens and reduce the reflectivity, thereby further enhancing the visual experience of optical equipment.

[0040] Optical glass and optical resin have good light transmittance and formability, which can meet the basic requirements of optical lenses for light propagation and shape shaping; while materials such as diamond, silicon carbide, and gallium nitride have high hardness, high wear resistance and excellent optical performance, which can maintain the stability and reliability of the lens in complex use environments. Selecting these materials as optical substrates can ensure that low reflectivity optical lenses can perform at their best in different application scenarios.

[0041] In this embodiment, a single-piece molding method is preferably adopted, with the optical substrate 1, the moth-eye film structure 3, and the grating structure 2 made of silicon carbide. In the actual processing, a silicon carbide wafer is first selected as the imprinting substrate. The wafer surface is cleaned and an oxide film layer is deposited. The grating structure 2 is patterned in the corresponding structural area, and a two-dimensional periodic array pattern is performed in the corresponding non-structural area. The pattern is transferred to the film layer on the wafer by etching. After removing the resist and cleaning, a nanoimprint template containing the patterns of the grating structure 2 and the moth-eye film structure 3 is formed. Then, a silicon carbide wafer is selected as the optical substrate 1, and nanoimprinting is performed on the optical substrate 1. A mask material is deposited on the lens, and an imprinting adhesive of a certain thickness is spin-coated. The structure on the nanoimprint template is imprinted onto the imprinting adhesive, and cured to form a stable pattern structure. Then, the residual imprinting adhesive on the wafer is etched away, the mask layer is etched, the wafer is etched, and the pattern of the imprinting adhesive is etched and transferred to the wafer. After removing the resist and the mask, the complete grating structure 2 and the moth-eye film structure 3 are formed.

[0042] Reference Figure 2 To further optimize the reflectivity and optical performance of the lens, the nanopillar 31 is frustum-shaped, with a period P = 115 nm, a base width D1 = 115 nm, a top width D2 = 60 nm, and a height H = 300 nm. The transmittance spectrum of the unstructured region of the lens in the visible light range is shown below. Figure 3 and Figure 4 As shown. Under normal incidence conditions, the visible light transmittance T>97%, and the high transmittance characteristic can be met within the incident angle range of 0~40°. When a two-dimensional structure with a period of 115nm is placed in the non-structured region, the light transmission path of the original grating structure will not change because the small period cannot meet the diffraction conditions of light in the waveguide.

[0043] Example 2: This is a low-reflectivity optical lens disclosed in this utility model. The difference from Example 1 is that the optical substrate 1, the moth-eye film structure 3 and the grating structure 2 are made of optical glass with a refractive index of 2.0.

[0044] The nanopillar 31 is frustum-shaped, with a period P = 180 nm, a base width D1 = 170 nm, a top width D2 = 50 nm, and a height H = 320 nm. The transmittance spectrum of the unstructured region of the lens in the visible light range is as follows... Figure 5 and Figure 6 As shown. Under normal incidence conditions, the visible light transmittance T>98%, and the high transmittance characteristic can be met within the incident angle range of 0~50°. When a two-dimensional structure with a period of 180nm is placed in the non-structured region, the light transmission path of the original grating structure will not change because the small period cannot meet the diffraction conditions of light in the waveguide.

[0045] Example 2: This is a low-reflectivity optical lens disclosed in this utility model. The difference from Example 1 is that the optical substrate 1, the moth-eye film structure 3 and the grating structure 2 are made of optical resin with a refractive index of 1.7.

[0046] The nanopillar 31 is frustum-shaped, with a period P = 186 nm, a base width D1 = 180 nm, a top width D2 = 60 nm, and a height H = 320 nm. The transmittance spectrum of the unstructured region of the lens in the visible light range is as follows... Figure 7 and Figure 8 As shown. Under normal incidence conditions, the visible light transmittance T>97%, and the high transmittance characteristic can be met within the incident angle range of 0~60°. When a two-dimensional structure with a period of 186nm is placed in the non-structured region, the light transmission path of the original grating structure will not change because the small period cannot meet the diffraction conditions of light in the waveguide.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit it. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the spirit and scope of the technical solutions of this utility model, and all such modifications or substitutions should be covered within the scope of the claims of this utility model.

Claims

1. A low-reflectivity optical lens, characterized in that: The device includes an optical substrate (1), a grating structure (2) disposed in the structural region of the optical substrate (1), and a moth-eye membrane structure (3) disposed in the non-structural region of the optical substrate (1). The moth-eye membrane structure (3) includes a plurality of nanopillars (31) arranged in a periodic array. The period P of the nanopillars (31) does not exceed 300 nm, and the cross-sectional area of ​​the nanopillars (31) decreases along the height direction.

2. The low-reflectivity optical lens according to claim 1, characterized in that: The materials of the moth-eye membrane structure (3) and the grating structure (2) are optical glass, optical resin, diamond, silicon carbide, or gallium nitride.

3. A low-reflectivity optical lens according to claim 2, characterized in that: The optical substrate (1) is made of optical glass, optical resin, diamond, silicon carbide, or gallium nitride.

4. A low-reflectivity optical lens according to claim 3, characterized in that: The grating structure (2) and the moth-eye membrane structure (3) are integrally formed with the optical substrate (1).

5. A low-reflectivity optical lens according to claim 3, characterized in that: The grating structure (2) and the moth-eye membrane structure (3) are disposed on the optical substrate (1) by coating or bonding.

6. A low-reflectivity optical lens according to claim 2, characterized in that: The period P of the nanopillar (31) is 200~300nm.

7. A low-reflectivity optical lens according to claim 6, characterized in that: The nanopillars (31) are frustum-shaped or prismatic.

8. A low-reflectivity optical lens according to claim 7, characterized in that: The bottom width D1 of the nanopillar (31) is 50~250nm.

9. A low-reflectivity optical lens according to claim 7, characterized in that: The top surface width D2 of the nanopillar (31) is 30~150nm.

10. A low-reflectivity optical lens according to claim 7, characterized in that: The height H of the nanopillar (31) is 100~500nm.

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