Polarizing Plate Warping Suppression via Low Moisture Permeability
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Solution Overview
Problem
The challenge is to create a thin polarizing plate that suppresses warping of display panels during bonding while maintaining durability under high temperature and high humidity conditions, as existing thinning technologies lead to reduced durability and warping issues due to deformation of polarizing films with low boric acid content.
Innovation Solution
A polarizing plate structure comprising a first adhesion layer, a transparent protective layer with low moisture permeability, a second adhesion layer with low water absorption, and a polarizing film with a boric acid content of 18 wt % or less, ensuring effective adhesion and protection without excessive deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the boric acid concentration in the polarizing film is reduced to minimize deformation, then the warping of the display panel is suppressed, but the durability of the polarizing film under high temperature and high humidity deteriorates
Solution Approach 1:
A transparent protective layer with low moisture permeability is introduced as an intermediary between the polarizing film and the external environment. This protective layer acts as a barrier that prevents moisture from reaching the polarizing film, thereby maintaining the film's durability even when the boric acid concentration is reduced to minimize deformation. The protective layer mediates between the need for low warping and the need for high durability.
Solution Approach 2:
The invention creates a composite structure consisting of multiple layers: the polarizing film with reduced boric acid concentration (for minimal deformation) combined with a transparent protective layer having specific moisture permeability characteristics (for durability). This composite material approach allows each layer to perform its specialized function, resolving the contradiction between minimizing warping and maintaining durability.
2Length of moving object
If the thickness of the polarizing plate is reduced to meet thinning requirements, then the overall device thickness is decreased, but the structural stability and resistance to deformation deteriorate
Solution Approach 1:
The thin polarizing plate achieves structural stability through a composite multi-layer structure. Even though the overall thickness is reduced, the combination of the polarizing film with the transparent protective layer and adhesion layers creates a structurally sound composite material that resists deformation and maintains stability despite the reduced thickness.
Solution Approach 2:
The polarizing plate is segmented into multiple functional layers with specific thicknesses and properties. The polarizing film is kept thin (6 μm or less) while the protective layer and adhesion layers provide the necessary structural support. This segmentation allows each layer to be optimized for its specific function while collectively achieving both thinness and stability.
3Length of moving object
If a single protective film is used to thin the polarizing plate, then the device thickness is reduced, but the adhesion strength and bonding reliability deteriorate
Solution Approach 1:
The protective system is segmented into multiple layers: a transparent protective layer for moisture protection and one or more adhesion layers for bonding strength. This segmentation allows the protective function and adhesion function to be separated and optimized independently, achieving both thinness and strong adhesion through the coordinated action of different layers.
Solution Approach 2:
The invention uses composite material structure where the transparent protective layer (for moisture barrier) is combined with adhesion layers (for bonding strength). This composite approach allows the thin polarizing plate to maintain both protective functionality and strong adhesion to the display panel, resolving the contradiction between thinness and bonding reliability.
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 solution effectively suppresses warping of display panels and enhances durability by reducing moisture penetration and expansion-contraction forces, maintaining optical performance and preventing deterioration of the polarizing film under high temperature and humidity.
Implementation Method 1
the transparent protective layer has a moisture permeability of 200 g/m2/24 hr or less
Implementation Method 2
the second adhesion layer has a bulk water absorption ratio of 10 wt % or less
Implementation Method 3
The arrangement results from the image-forming system of the apparatus. The polarizing plate typically includes a polarizing film and a protective film for protecting the polarizing film
Data Source
AI summary
A polarizing plate of the present invention includes: a first adhesion layer, a transparent protective layer, a second adhesion layer, and a polarizing film in the stated order, wherein: the first adhesion layer has a thickness of 10 μm or more; the transparent protective layer has a thickness of 30 μm or less; the transparent protective layer has a moisture permeability of 200 g/m2/24 hr or less; the second adhesion layer has a bulk water absorption ratio of 10 wt % or less; the polarizing film has a thickness of 10 μm or less; and the polarizing film has a boric acid content of 18 wt % or less with respect to a weight of the polarizing film.