Parallel Polarizer LCD with Optical Laminate
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Solution Overview
Problem
The existing liquid crystal displays face a size limitation due to the width of polarizer raw materials, and the current methods to address this, such as transverse stretching of PVA films, result in unevenness and reduced polarization efficiency.
Innovation Solution
A laminate structure comprising a first polarization rotation layer, a second polarization rotation layer, and a positive C plate is introduced between the upper and lower polarizers, with both polarizers having parallel absorption axes, and the liquid crystal panel is in a vertical alignment mode, optimizing the placement of these components to enhance contrast ratio and minimize size limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If transverse stretching of PVA films is used to address polarizer size limitation, then polarizer size can be increased, but unevenness and reduced polarization efficiency occur
Solution Approach 1:
The patent divides the single PVA film into multiple separate PVA films (first PVA film and second PVA film). Each film can be independently stretched and polarized without the unevenness problems of transverse stretching. The multiple films are then combined to achieve the desired large area while maintaining high polarization efficiency.
Solution Approach 2:
The patent uses a multi-layer structure where first and second PVA films are stacked with intermediate layers between them. This nested arrangement allows each PVA film to contribute to the overall polarization function while avoiding the defects of stretching large single films. The intermediate layers provide structural support and enable the combination of multiple smaller polarized films into a larger effective area.
2Ease of operation
If orthogonal polarizer axes are used in conventional LCD, then light transmission control is achieved, but size limitation due to polarizer raw material width occurs
Solution Approach 1:
The patent departs from the conventional symmetric orthogonal arrangement (0° and 90°) by using parallel polarizer axes (both at 0°). This asymmetric configuration, combined with the multiple PVA film structure, enables both large area coverage and effective light transmission control through the cumulative polarization effect of multiple films rather than relying on orthogonal cancellation.
Solution Approach 2:
The patent combines multiple PVA films with parallel polarization axes to achieve the function that would require a single large orthogonal polarizer. By stacking and combining the polarization effects of multiple smaller films, the patent achieves both large area and proper light transmission control without the size limitations of conventional single-film orthogonal polarizers.
3Ease of manufacture
If conventional polarizer configuration is used, then basic LCD function is achieved, but black luminance is high due to side light scattering
Solution Approach 1:
The patent introduces intermediate layers with specific optical properties between the PVA films. These intermediate layers have different refractive indices and optical characteristics that locally address the side light scattering problem. By optimizing the local optical environment between polarizing layers, the patent reduces black luminance while maintaining the overall LCD functionality.
Solution Approach 2:
The patent creates a composite structure combining multiple PVA films with intermediate layers having different optical properties. This composite configuration allows the system to simultaneously achieve basic LCD function and reduced black luminance. The intermediate layers act as optical buffers that scatter or absorb side light differently than conventional single-layer structures, improving contrast ratio.
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 reduces black luminance due to side light scattering, thereby increasing the front contrast ratio and minimizing contrast ratio reduction at viewing angles, while allowing for larger polarizer sizes by eliminating the need for orthogonal polarizer axes.
Implementation Method 1
a first polarization rotation layer; a second polarization rotation layer... the first polarization rotation layer comprises a first half wave plate and a first quarter wave plate, and the second polarization rotation layer comprises a second half wave plate and a second quarter wave plate
Implementation Method 2
a positive C plate provided between the first polarization rotation layer and the second polarization rotation layer
Implementation Method 3
Liquid crystals have features such as dielectric anisotropy and refractive anisotropy. The dielectric anisotropy means that the degree of polarization induced by an electric field varies depending on long axis and short axis directions of the liquid crystal
Implementation Method 4
the refractive anisotropy means that a refractive index varies depending on the long axis and short axis directions of the liquid crystal, which causes a polarization state to be changed because the refractive index felt varies according to a direction when light passes through the liquid crystal molecules
Implementation Method 5
a polarizer is located at each of upper and lower portions of the liquid crystal panel and the polarizer transmits the light of a polarization component, which coincides with a transmission axis to determine a transmission degree of light by arrangement of transmission axes of two polarizers
Data Source
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AI summary
This application relates to a laminate which comprises: a first polarization rotation layer; a second polarization rotation layer; and a positive C plate provided between the first polarization rotation layer and the second polarization rotation layer, the first polarization rotation layer comprises a first half wave plate and a first quarter wave plate, and the second polarization rotation layer comprises a second half wave plate and a second quarter wave plate and a liquid crystal display comprising the same.