Layered Lens Coating Structure for Low Reflectance Without Cracks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lenses with nano-porous structures (NPS) face issues with increased crack occurrence due to stress between thin films during hot water treatment, leading to higher defect rates, especially under thermal shock conditions.
Innovation Solution
A lens design featuring a split layer within the first coating film, dividing it into two expansion layers with different thicknesses and refractive indices, combined with a nano-porous second coating film, reduces stress and crack formation, while maintaining low reflectance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a nano-porous structure is applied to reduce reflectance, then reflectance is lowered to approximately 0.15% or less, but cracks occur due to stress between thin films during hot water treatment or reliability evaluation
Solution Approach 1:
The first coating film is divided into two separate expansion layers (first expansion layer and second expansion layer) with different thicknesses and refractive indices. This segmentation allows each layer to accommodate thermal expansion differently, reducing internal stress and preventing cracks during hot water treatment while maintaining the low reflectance property of the nano-porous structure.
Solution Approach 2:
Different regions of the coating structure are assigned different properties: the first expansion layer has a specific thickness and refractive index optimized for stress management, while the second expansion layer has different properties. This local differentiation enables each layer to function optimally in reducing stress concentration, thereby preventing crack formation while preserving the overall anti-reflective performance.
2Illumination intensity
If multiple thin films are deposited to create low-reflection lens, then reflectance is reduced to less than about 0.5%, but stress between thin films increases during manufacturing processes
Solution Approach 1:
The coating structure is segmented into multiple functional layers with gradually varying refractive indices and thicknesses. This segmentation creates a more gradual transition in optical and mechanical properties, reducing stress concentration at interfaces between films with vastly different properties, thereby preventing cracks while maintaining low reflectance.
Solution Approach 2:
The refractive index and thickness parameters are carefully optimized for each layer. By creating a gradient in these parameters across the different expansion layers, the patent reduces stress accumulation during thermal processing while maintaining the desired optical performance for low reflectance.
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 split layer design significantly reduces crack occurrence rates and maintains low reflectance, improving reliability and reducing manufacturing costs through optimized film thickness and deposition time.
Implementation Method 1
a second coating film disposed on the first coating film and having a nano porous structure (NPS)
Implementation Method 2
The second coating film may have a graded index in which a refractive index increases from an upper end of the second coating film to a lower end of the second coating film
Implementation Method 3
a first coating film disposed on the substrate, and comprising a split layer that divides the first coating film into two layers
Data Source
AI summary
A lens with a layered extension portion is provided. The lens includes a substrate; a first coating film disposed on the substrate, and including a split layer that divides the first coating film into two layers; and a second coating film disposed on the first coating film and having a nano-porous structure (NPS).