Circularly Polarizing Plate Thinning with Elastic Support
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Solution Overview
Problem
Conventional circularly polarizing plates used in display devices do not adequately address the issues of tint change and reflectivity differences between the center and edge portions, especially under high temperature conditions, and fail to achieve sufficient thinning of the display device.
Innovation Solution
A circularly polarizing plate configuration featuring a polarizer, a transparent support with a thickness of 50 μm or less, and an optically anisotropic layer, where the transparent support has a modulus of elasticity ratio between the maximum and minimum values within a specific range, and the optically anisotropic layer includes a λ/2 plate and a λ/4 plate, effectively reducing tint change and reflectivity differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional circularly polarizing plate is used, then the display device can function, but the amount of change in tint and difference in reflectivity between center and side edge portions increases under high temperature conditions
Solution Approach 1:
The patent changes the physical parameters of the transparent support, specifically controlling its thickness to 50 μm or less and adjusting the ratio between maximum and minimum modulus of elasticity values to fall within a predetermined range. These parameter changes enable the support to maintain dimensional stability under high temperature conditions, thereby reducing tint change and reflectivity difference while improving overall durability
Solution Approach 2:
The patent employs a composite structure consisting of a polarizer, a transparent support with specific elastic properties, and an optically anisotropic layer. This composite material approach allows the transparent support to act as a buffer that compensates for thermal expansion differences between layers, maintaining optical uniformity under temperature variations
2Length of moving object
If the circularly polarizing plate is thinned to reduce display device thickness, then the display device can be thinned, but the durability and stability under high temperature conditions deteriorate
Solution Approach 1:
The patent identifies thickness and elastic modulus ratio as critical parameters. By setting the transparent support thickness to 50 μm or less while simultaneously controlling the elastic modulus ratio within a specific range, the patent achieves both thinning of the display device and maintenance of high-temperature durability. This dual parameter optimization resolves the contradiction between thinning and reliability
Solution Approach 2:
The patent uses a thin transparent support film with specifically controlled elastic properties. The film's thinness enables display device reduction, while its controlled elastic modulus ratio provides the necessary mechanical flexibility and thermal stability to maintain durability, demonstrating the effective use of thin films with optimized mechanical properties
3Ease of manufacture
If a conventional transparent support is used, then the circularly polarizing plate can be assembled, but the amount of change in tint and difference in reflectivity cannot be reduced
Solution Approach 1:
The patent specifies precise parameter ranges for the transparent support (thickness ≤50 μm and controlled elastic modulus ratio) that simultaneously facilitate manufacturing assembly and ensure optical stability. These parameter specifications make the manufacturing process straightforward while achieving the desired reduction in tint change and reflectivity difference
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 proposed configuration significantly reduces tint change and reflectivity differences while enabling the thinning of display devices, enhancing their durability and performance in high-temperature environments.
Implementation Method 1
an optically anisotropic layer including a liquid crystal compound
Implementation Method 2
an optically anisotropic layer including a liquid crystal compound
Implementation Method 3
a ratio between a maximum value and a minimum value of modulus of elasticity (maximum value/minimum value) in a plane set to be in a predetermined range
Implementation Method 4
a circularly polarizing plate comprising: a polarizer; a transparent support; and an optically anisotropic layer including a liquid crystal compound
Data Source
AI summary
The present invention provides a circularly polarizing plate capable of reducing the amount of change in tint and a difference in reflectivity while achieving thinning of a display device and a display device having the same. The circularly polarizing plate of the present invention includes a polarizer, a transparent support, an optically anisotropic layer including a liquid crystal compound in this order, in which the optically anisotropic layer satisfies Expression (1) and the transparent support has a thickness of 50 μm or less and satisfied Expression (2), 100≤Re(550)≤180 nm . . . (1) and 1.00≤R≤1.20 . . . (2), in Expression (1), Re(550) represents an in-plane retardation of the optically anisotropic layer at a wavelength of 550 nm and in Expression (2), R represents a ratio between a maximum value and a minimum value of modulus of elasticity of the transparent support.