Light Guide Panel with Birefringent Polarization Separation
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Solution Overview
Problem
Liquid crystal displays face inefficiencies in light usage and luminance due to absorption-type polarization plates, which limit light transmittance to 50% and require costly manufacturing processes for reflective polarization plates like DBEF, and existing solutions for improving polarization separation are not cost-effective.
Innovation Solution
A light guide panel with a polarization separation layer and a light homogenization layer, comprising birefringent fibers and isotropic supporting media, that selectively emits desired polarization components and diffuses light to achieve uniform luminance even with discontinuous light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If absorption-type polarization plate is used, then polarization function is achieved, but light usage efficiency is limited to 50% maximum
Solution Approach 1:
The patent changes the working principle of the polarization plate from absorption to reflection. By using a reflective polarization plate with a specific refractive index structure (isotropic layer with n=1.49 and anisotropic layer with n=1.69), the system reflects unwanted polarization components instead of absorbing them, thereby improving light usage efficiency while maintaining the polarization function.
Solution Approach 2:
The patent replaces the absorption mechanism with a reflection mechanism. The reflective polarization plate uses optical reflection and interference to separate polarization components, substituting the mechanical/chemical absorption process with an optical reflection process that preserves more light energy.
2Loss of energy
If reflective polarization plate (DBEF) is used to improve light usage efficiency, then polarization separation is improved, but manufacturing cost increases due to complex multi-layer structure
Solution Approach 1:
The patent extracts the essential function of polarization separation from the complex multi-layer DBEF structure and implements it through a simpler reflective polarization plate configuration. By focusing on the key refractive index relationship between isotropic and anisotropic layers, the design achieves polarization separation without requiring hundreds of stacked layers.
Solution Approach 2:
The patent simplifies the structure by changing the design parameters from multiple thin layers to a fewer number of thicker layers with specific refractive indices. The reflective polarization plate uses controlled thickness values (e.g., 50-200 μm for isotropic layer, 10-50 μm for anisotropic layer) to achieve the desired optical effect with reduced complexity.
3Use of energy by stationary object
If discontinuous light source is used, then power consumption is reduced, but luminance spots occur due to non-uniform light distribution
Solution Approach 1:
The patent introduces a light homogenization layer as an intermediary between the discontinuous LED light sources and the display panel. This layer, containing scattering particles or structures, acts as a mediator that redistributes the light from discrete sources to create a uniform illumination across the entire display area, eliminating luminance spots.
Solution Approach 2:
The patent applies local quality changes by introducing scattering centers at specific locations within the light homogenization layer. These localized scattering elements redirect light in specific directions to compensate for the non-uniform distribution from discrete LED sources, creating uniform overall illumination.
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 solution enhances polarization separation efficiency and prevents luminance spots, improving light usage efficiency and reducing manufacturing costs by uniformly distributing light across the display panel.
Implementation Method 1
a polarization separation layer configured to select a desired polarization among light emitted from the light guide layer and to emit light having the polarization
Implementation Method 2
a light homogenization layer including a plurality of first fibers and a first supporting medium of the first fibers, the light homogenization layer configured to diffuse and scatter light incident on the light guide layer into the light guide layer
Data Source
AI summary
A light guide panel includes: a light guide layer having a light incident surface; a polarization separation layer configured to select a desired polarization among light emitted from the light guide layer and to emit light having the polarization; and a light homogenization layer including a plurality of fibers and a supporting medium of the fibers, the light homogenization layer configured to diffuse and scatter light incident on the light guide layer into the light guide layer. The polarization separation layer includes: a plurality of first fibers having birefringence; and a first supporting medium that is isotropic and configured to support the first fibers. The refractive index of the first supporting medium corresponds to at least one of two different refractive indices of the first fibers. The light homogenization layer includes: a plurality of second fibers having birefringence; and a second supporting medium that is isotropic and configured to support the second fibers.