PEDOT:PSS Bonding Layer for In-Cell Touch Polarizing Plates
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Solution Overview
Problem
Conventional liquid crystal display devices with in-cell type touch sensors face challenges in maintaining touch performance and sensitivity at high temperatures and humidity levels, and suffer from increased thickness due to the use of anchor layers, which also degrade over time.
Innovation Solution
A polarizing plate with a bonding layer comprising poly(ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and a salt of glyoxylic acid, providing a surface resistance of 1×10^8 to 1×10^12 Ω/□ before and after exposure to high temperature and humidity, ensuring consistent touch performance and sensitivity, and enhancing adhesive strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an anchor layer including a conductive polymer is formed on the outside of the liquid crystal panel to achieve predetermined sheet resistance, then touch performance is improved, but the thickness of the liquid crystal display device increases
Solution Approach 1:
The patent combines the anchor layer function with the bonding layer function by incorporating conductive polymer particles into the bonding layer composition. This merging eliminates the need for a separate anchor layer while maintaining both bonding strength and touch performance, thereby reducing overall device thickness.
Solution Approach 2:
The bonding layer is designed to perform multiple functions simultaneously: it provides adhesive bonding between the polarizing plate and protective film, maintains predetermined sheet resistance for touch sensor operation, and offers durability against high temperature and humidity. This multi-functionality eliminates the need for separate anchor layer.
2Reliability
If an anchor layer is added to maintain sheet resistance, then touch sensitivity is improved, but the device complexity increases
Solution Approach 1:
The patent merges the anchor layer and bonding layer into a single integrated bonding layer structure. This reduces the number of layers and simplifies the overall device structure while maintaining both touch sensitivity and bonding functionality.
Solution Approach 2:
The bonding layer is designed to perform multiple functions simultaneously: adhesive bonding, maintaining sheet resistance for touch sensitivity, and providing durability. This multi-functional design eliminates the need for separate anchor layer, thereby reducing device complexity.
3Strength
If conventional bonding materials are used, then adhesive strength is achieved, but surface resistance changes under high temperature and humidity conditions
Solution Approach 1:
The patent uses a composite bonding layer material consisting of polyvinyl alcohol resin combined with conductive polymer particles (polyethylene dioxythiophene poly styrene sulfonate). This composite structure provides both adhesive strength from the resin and stable surface resistance from the conductive particles, even under high temperature and humidity conditions.
Solution Approach 2:
The patent modifies the bonding layer composition by adding conductive polymer particles to the polyvinyl alcohol resin. This parameter change in material composition enables the bonding layer to maintain both adhesive strength and stable surface resistance under varying environmental conditions.
4Ease of manufacture
If the polarizing plate structure is simplified, then manufacturing ease is improved, but touch performance at high temperature and humidity deteriorates
Solution Approach 1:
The bonding layer is designed to perform multiple functions simultaneously: adhesive bonding, maintaining sheet resistance for touch performance, and providing durability against high temperature and humidity. This multi-functionality in a single layer simplifies manufacturing while ensuring reliable touch performance under various conditions.
Solution Approach 2:
The use of composite bonding layer material (polyvinyl alcohol resin with conductive polymer particles) provides both adhesive properties and stable electrical properties in a single layer, simplifying the overall structure while maintaining touch performance under high temperature and humidity conditions.
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 maintains excellent touch performance and sensitivity at room and high temperature/humidity conditions, with short recolor time against electrostatic shock, and provides high reliability and water resistance when laminated on an in-cell liquid crystal panel.
Implementation Method 1
the bonding layer for polarizing plates comprises a poly(ethylenedioxythiophene) poly(styrenesulfonate)(PEDOT:PSS), and a salt of glyoxylic acid
Data Source
AI summary
Provided are a polarizing plate, a polarizing plate adhesive composition for same, and an optical display apparatus comprising same, the polarizing plate comprising: a polarizer; and a polarizing plate adhesive layer and a protective layer which are sequentially formed on at least one surface of the polarizer, wherein the polarizing plate adhesive layer comprises poly(ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), and the polarizing plate adhesive layer has a surface resistance of about 1×108 to about 1×1012(Ω/□).