Optical Film Microstructure Sidewall Absorptive Layer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical films with microstructures suffer from undesired light redirection due to the presence of sidewalls, which can be mitigated by incorporating optically absorptive layers but often result in increased surface roughness and reflectivity.
Innovation Solution
The optical film features a polymeric layer with a microstructured surface conformally coated with an inorganic optically transparent layer, where each microstructure includes an optical facet and a sidewall defining an oblique angle. An optically absorptive layer is disposed on the sidewall, and a first layer with a lower extinction coefficient than the absorptive layer is interposed between the sidewall and the absorptive layer to reduce reflectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an optically absorptive layer is disposed on the sidewall to reduce undesired light redirection, then light absorption is improved, but surface roughness and reflectivity increase
Solution Approach 1:
The patent applies different properties to different parts of the microstructure: the optical facet maintains high transparency and smoothness for light transmission, while the sidewall incorporates an optically absorptive layer for light absorption. This local differentiation allows each surface to perform its specific function optimally without compromising the other.
Solution Approach 2:
The patent introduces an inorganic optically transparent layer as an intermediary between the polymeric microstructured layer and the optically absorptive layer. This intermediate layer acts as a buffer that prevents the absorptive layer from directly contacting and roughening the optical facet, thereby maintaining smooth surfaces while still allowing the absorptive layer to function on the sidewall.
2Loss of energy
If the optically absorptive layer is made thicker to improve light absorption, then absorption efficiency increases, but manufacturing precision and surface smoothness deteriorate
Solution Approach 1:
The patent confines the optically absorptive layer to a specific dimension - the sidewall surface - rather than applying it uniformly across all surfaces. By limiting the absorptive layer's presence to the sidewall region and using the inorganic transparent layer as a barrier on the optical facet, the system achieves effective light absorption without sacrificing the smoothness and precision of the optical surfaces.
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
This configuration effectively reduces undesired light redirection by absorbing light on the sidewalls, while maintaining a smooth optical facet with reduced surface roughness, thereby enhancing the optical performance of the film.
Implementation Method 1
an optically absorptive layer is disposed on the sidewall... effectively reduces undesired light redirection by absorbing light on the sidewalls
Implementation Method 2
an inorganic optically transparent layer... maintaining a smooth optical facet with reduced surface roughness
Data Source
AI summary
An optical film has a major surface including a plurality of microstructures. Each microstructure includes an optical facet and a sidewall meeting the optical facet at a ridge of the microstructure. The optical facet and the sidewall define an oblique angle therebetween. For each microstructure in at least a majority of the microstructures, an optically absorptive layer is disposed on the sidewall. The optical film can include a polymeric layer having a microstructured surface at least partially coated with an inorganic optically transparent layer. The optically absorptive layer can an average thickness t where 100 nm<t<1 micrometer. A first layer can be disposed between the sidewall and the optically absorptive layer where the first layer has a lower extinction coefficient than the optically absorptive layer.