Polarizing Plate Bonding Layer for Foldable Displays
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Solution Overview
Problem
Existing polarizing plates for light emitting displays face challenges in achieving high peel strength and reliability, especially under high temperature and humidity conditions, and in minimizing the influence on polarized light passing through liquid crystal retardation films, while also requiring flexibility for foldable displays.
Innovation Solution
A polarizing plate design featuring a polarizer, a first liquid crystal retardation film, a first bonding layer with a glass transition temperature of 70° C. to 100° C., and a second liquid crystal retardation film, where the first bonding layer is formed using a composition including alicyclic group-containing glycidyl ether and aromatic group-containing glycidyl ether, ensuring strong adhesion and flexibility, and a second bonding layer with a different glass transition temperature, optionally a protective layer, to enhance durability and light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bonding layer is used to join liquid crystal retardation films, then peel strength is improved, but the bonding layer may influence or distort polarized light passing through the structure
Solution Approach 1:
The patent changes the chemical composition parameters of the bonding layer by selecting specific epoxy compounds (alicyclic group-containing and aromatic group-containing glycidyl ethers) that provide both high peel strength and minimal optical interference with polarized light
Solution Approach 2:
The bonding layer is formulated as a composite material combining specific epoxy compounds with controlled glass transition temperature (70-100°C), achieving a balance between mechanical adhesion properties and optical transparency to polarized light
2Reliability
If the polarizing plate structure is made robust for high temperature reliability, then reliability under high temperature and humidity conditions is improved, but flexibility for foldable displays deteriorates
Solution Approach 1:
The glass transition temperature of the bonding layer is precisely controlled within 70-100°C, creating a material that maintains structural integrity at high temperatures while remaining sufficiently flexible at operating temperatures to enable foldable display applications
Solution Approach 2:
The bonding layer exhibits temperature-dependent properties: at high temperatures it provides reliable adhesion and structural stability, while at lower operating temperatures it maintains the flexibility needed for foldable displays
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 provides improved peel strength, reliability, and flexibility, maintaining low polarization degree variation under high temperature and humidity conditions, and effectively reduces light reflection, enhancing the performance of light emitting displays, including foldable ones.
Implementation Method 1
a first bonding layer having a glass transition temperature of about 70° C. to about 100° C. and formed of a composition including at least one selected from among an alicyclic group-containing glycidyl ether and an aromatic group-containing glycidyl ether
Data Source
AI summary
A polarizing plate for light emitting displays and a light emitting display including the same are provided. A polarizing plate includes: a polarizer; and a first liquid crystal retardation film, a first bonding layer, and a second liquid crystal retardation film sequentially stacked on a surface of the polarizer, and the first bonding layer has a glass transition temperature of about 70° C. to about 100° C. and is formed of a composition including at least one selected from among an alicyclic group-containing glycidyl ether and an aromatic group-containing glycidyl ether.