Polarizing Plate with Refractive Index Pattern Layers for LCD Lateral Viewing
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Solution Overview
Problem
Liquid crystal displays (LCDs) typically exhibit lower color quality, contrast ratio, and viewing angle at lateral sides compared to the front side, and as screen size increases, brightness uniformity deteriorates, requiring separate modules and complicating processability and economic feasibility.
Innovation Solution
A polarizing plate is designed with a stack structure that includes a polarizer, a pattern layer with a high refractive index layer having an engraved pattern and a low refractive index layer with a filling pattern, and a protective layer. This configuration enhances light diffusion and improves contrast ratio, viewing angle, and brightness uniformity at lateral sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the liquid crystal display uses conventional liquid crystal panel structures, then the manufacturing process is simple, but the color quality and contrast ratio at lateral sides are poor
Solution Approach 1:
The patent divides the liquid crystal display system into separate functional modules: a liquid crystal panel and a polarizing plate with integrated optical compensation layers. The pattern layers with different refractive indices are segmented and positioned at specific locations (front and rear of the liquid crystal panel) to independently control optical properties at lateral sides without complicating the liquid crystal panel manufacturing process
Solution Approach 2:
The patent introduces a polarizing plate as an intermediary component between the light source and the liquid crystal panel. This polarizing plate contains pattern layers with different refractive indices that act as mediators to compensate for optical deficiencies at lateral sides, thereby improving color quality and contrast ratio without modifying the liquid crystal panel structure itself
2Area of stationary object
If the screen size of the liquid crystal display is increased, then the display area is larger, but the brightness uniformity deteriorates
Solution Approach 1:
The patent applies pattern layers with different refractive indices at specific local positions (front and rear of the liquid crystal panel) rather than uniformly across the entire display. These localized optical compensation structures address brightness non-uniformity in critical viewing areas while maintaining large overall display area
Solution Approach 2:
The patent addresses brightness uniformity issues by adding optical compensation in the depth dimension (front and rear pattern layers) rather than only in the planar dimensions. This three-dimensional arrangement of optical layers compensates for light path variations across large screen areas, maintaining brightness uniformity as screen size increases
3Manufacturing precision
If the liquid crystal display is designed to improve color quality and contrast ratio at lateral sides, then the optical performance is improved, but the process becomes complicated
Solution Approach 1:
The patent merges the optical compensation function into the polarizing plate structure by integrating pattern layers with different refractive indices directly into the polarizing plate. This consolidation allows multiple optical functions (polarization and lateral side compensation) to be achieved in a single component, improving color quality and contrast ratio without proportionally increasing process complexity
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 polarizing plate significantly improves contrast ratio and viewing angle at lateral sides of LCDs while maintaining brightness uniformity, even with increasing screen size, thus enhancing processability and economic feasibility.
Implementation Method 1
a pattern layer on one surface of the polarizer, the pattern layer including a first refractive index layer having at least one engraved pattern and a second refractive index layer having a filling pattern filling at least a portion of the engraved pattern
Implementation Method 2
the first refractive index layer having a higher refractive index than the second refractive index layer
Data Source
AI summary
A polarizing plate includes: a polarizer; a pattern layer on one surface of the polarizer, the pattern layer including a first refractive index layer having at least one engraved pattern and a second refractive index layer having a filling pattern filling at least a portion of the engraved pattern, the first refractive index layer having a higher refractive index than the second refractive index layer; and a first protective layer. The polarizing plate has a structure in which the polarizer, the second refractive index layer, the first refractive index layer and the first protective layer are sequentially stacked in that order, or in which the polarizer, the first protective layer, the second refractive index layer and the first refractive index layer are sequentially stacked in that order. The first protective layer includes a base film including at least one resin of triacetylcellulose, polyethylene terephthalate, cyclic olefin polymer, and acrylic resins.