Light Control Film Structure for High Transmission and Privacy
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Solution Overview
Problem
Traditional louver-based light control films have limited on-axis light transmission due to aspect ratios, and there is a need for higher aspect ratios with a high extinction coefficient to efficiently absorb light and reduce high angle light leakage and ghosting.
Innovation Solution
A light control film design with alternating transmissive and absorptive regions, where the absorptive regions comprise a core sandwiched between cladding layers, having a lower concentration of light absorbing material, and an aspect ratio of at least 20, to enhance on-axis light transmission and reduce off-axis light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional louver-based light control films use aspect ratios of 10:1 to 15:1, then manufacturing is simpler, but on-axis light transmission is limited
Solution Approach 1:
The absorptive region is segmented into three distinct layers: a core layer with high light absorbing material concentration and two cladding layers with lower concentration. This segmentation allows the core to provide strong light absorption while the cladding layers reduce reflectivity and enable higher aspect ratios, achieving both high on-axis light transmission and manufacturability
Solution Approach 2:
Different layers within the absorptive region have different local qualities - the core layer has high light absorbing material concentration for maximum absorption, while the cladding layers have lower concentration to reduce reflectivity. This local quality variation optimizes both light transmission and absorption performance
2Loss of energy
If high aspect ratio louvers have high extinction coefficient to efficiently absorb light, then light absorption improves, but reflectivity increases creating metal-like interface
Solution Approach 1:
The cladding layers act as intermediary layers between the high extinction coefficient core and the transmissive regions. These intermediate layers with lower light absorbing material concentration reduce the metal-like reflective interface while allowing the core to maintain its high light absorption efficiency
Solution Approach 2:
The absorptive region uses a composite structure with three layers having different light absorbing material concentrations. The core layer provides high absorption while the cladding layers provide optical matching and reduced reflectivity, creating a composite material system that balances absorption efficiency and reflectivity
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 design achieves increased on-axis light transmission up to 92.3% and significantly lower transmission at off-axis angles, suitable for privacy films by blocking views at angles beyond 30 degrees.
Implementation Method 1
the absorptive regions comprise a core having a first concentration, C1, of a light absorbing material sandwiched between cladding layers having a second concentration, C2, of the light absorbing material, wherein C2 < C1
Data Source
AI summary
A light control film comprises a light input surface and a light output surface opposite the light input surface; alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein the absorptive regions comprise a core having a first concentration, C1, of a light absorbing material sandwiched between cladding layers having a second concentration, C2, of the light absorbing material, wherein C2<C1, and wherein the cores have an aspect ratio of at least 20.