Anti-Reflection Film With Gradient Refractive Index For Wide-Angle Lenses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional anti-reflection films, such as dielectric multilayer films, fail to provide high anti-reflection performance across a wide wavelength band and large incident angle range, especially when applied to lenses with large curvature, leading to issues like flare and ghost in digital camera images.
Innovation Solution
An optical element with an anti-reflection film comprising a first layer, a second layer of different material, and a third layer with a concave-convex structure, where the refractive index changes at a constant rate due to varying space filling factors, enhancing both wavelength band and incident angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dielectric multilayer film is used as an anti-reflection film, then anti-reflection performance is improved at a specific wavelength or incident angle, but anti-reflection performance deteriorates across a wide wavelength band or large incident angle range
Solution Approach 1:
The patent applies local quality by creating a concave-convex structure on the film surface that varies the local thickness and refractive index distribution. This local variation allows different regions of the film to optimize anti-reflection performance for different wavelengths and incident angles simultaneously, resolving the contradiction between performance at specific conditions and performance across wide ranges.
Solution Approach 2:
The patent uses composite materials by combining multiple dielectric layers with different refractive indices and incorporating a concave-convex structure. This composite structure integrates the advantages of multiple layers (interference control) with the surface modulation (wavelength and angle broadening), achieving both specific performance optimization and wide-band adaptability.
2Ease of manufacture
If a vacuum deposition method is used to form an anti-reflection film on a lens with large curvature, then film deposition is achieved, but the film thickness becomes non-uniform (thinner at peripheral parts) causing poor anti-reflection performance
Solution Approach 1:
The patent applies preliminary action by pre-forming a concave-convex structure on the film surface during the deposition process. This preliminary structural modification compensates for the thickness variation inherent in vacuum deposition on curved surfaces, ensuring uniform optical performance across the entire lens surface including peripheral areas.
Solution Approach 2:
The patent changes the physical parameters of the film by introducing a concave-convex structure that modifies the thickness distribution and refractive index profile. This parameter change transforms the non-uniform vacuum deposition film into a functionally uniform anti-reflection film with consistent performance across varying incident angles and wavelengths.
3Manufacturing precision
If a shielding with opening is provided during vacuum deposition to ensure uniform film thickness, then film thickness uniformity is improved, but deposition efficiency decreases and productivity is reduced
Solution Approach 1:
The patent applies preliminary action by incorporating the concave-convex structure formation directly into the deposition process itself, eliminating the need for separate shielding components. This integrated approach achieves uniform film thickness and maintains high deposition efficiency simultaneously, resolving the contradiction between precision and productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed anti-reflection film achieves excellent performance across the entire visible wavelength region and large incident angle range, reducing flare and ghost occurrences, while also improving productivity by using a wet process instead of vacuum deposition.
Implementation Method 1
the amplitudes and the phases of reflected waves generated on the surfaces and the interfaces of the films are adjusted and made to interfere with each other so as to reduce reflected light
Implementation Method 2
a third layer formed on the second layer and having a concave-convex structure, and wherein the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure
Data Source
AI summary
The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.