Light Control Film Structure for High Transmission and Low Ghosting
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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, featuring high aspect ratio louvers and cladding layers on each side of a high extinction coefficient core, which reduces louver reflectivity and enhances light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional louver-based light control films are used with conventional aspect ratios, then manufacturing is simpler, but on-axis light transmission is limited
Solution Approach 1:
The patent increases the louver aspect ratio from conventional values to at least 20:1, fundamentally changing the geometric parameters of the light control film. This parameter change enables significantly improved on-axis light transmission while maintaining the light control function, directly resolving the contradiction between transmission performance and structural complexity.
Solution Approach 2:
The patent introduces a multi-layer cladding structure (first cladding layer and second cladding layer with different extinction coefficients) around the core louver, adding dimensional complexity to the cross-sectional structure. This dimensional enhancement allows the high aspect ratio louvers to maintain low reflectivity and reduce high-angle light leakage, supporting the improved on-axis transmission without compromising light control.
2Object-affected harmful factors
If high aspect ratio louvers with high extinction coefficient are used to reduce light leakage, then off-axis light blocking is improved, but louver reflectivity increases causing ghosting
Solution Approach 1:
The patent applies different extinction coefficients to different regions of the louver structure. The core louver has a high extinction coefficient for light absorption, while the first cladding layer has a lower extinction coefficient to reduce reflectivity. This local differentiation of material properties allows simultaneous achievement of high off-axis light blocking and reduced ghosting effects.
Solution Approach 2:
The patent creates a composite louver structure consisting of a core region with high extinction coefficient material and cladding regions with lower extinction coefficient materials. This composite structure combines the light-absorbing properties of high extinction coefficient materials with the light-scattering properties of lower extinction coefficient materials, effectively reducing both high-angle light leakage and reflectivity-induced ghosting.
3Illumination intensity
If high aspect ratio louvers are used to improve on-axis light transmission, then privacy performance is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent segments the louver structure into distinct functional regions: a core region and multiple cladding layers. This segmentation allows each region to be optimized independently for its specific function (light absorption vs. reflectivity reduction), making the overall high aspect ratio structure more manufacturable by distributing precision requirements across multiple manageable components rather than requiring uniform precision throughout the entire structure.
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 while significantly reducing light leakage and ghosting, making it suitable for privacy films that allow direct viewers to see while blocking off-axis angles.
Implementation Method 1
absorptive regions (140) including a core (141) and a cladding layer (142)... high extinction coefficient core, which reduces louver reflectivity and thereby reduces high angle light leakage and ghosting
Data Source
Figure 1a~1b
Figure 2~3b
Figure 3c~3f
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.