Display Window Hard Coating Adhesion via Silane Promoter
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Solution Overview
Problem
The existing display window technologies face challenges in achieving secure adhesion between the hard coating layer and the decoration layer, often resulting in peeling-off issues due to the low surface hardness and chemical resistance of materials like poly(methyl methacrylate) and polyethylene terephthalate, which are commonly used in slim-type display devices.
Innovation Solution
A display device configuration that includes a window substrate with a first and second hard coating layer, a protection layer, an auxiliary adhesive layer, and a base film, where the auxiliary adhesive layer is applied on the second hard coating layer to enhance adhesion, using compounds like alkylsilane or perfluorosilane, and UV-curable hard coating compositions to improve surface hardness and chemical resistance, and a light shielding layer on the base film to prevent peeling-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasma treatment is used to enhance the adhesion of the hard coating layer, then the adhesion between the hard coating layer and the decoration layer is improved, but the display window is bent due to heat generated during the plasma treatment
Solution Approach 1:
The patent replaces the plasma treatment process (which generates heat causing bending) with a chemical adhesion promoter layer that provides strong bonding without thermal effects. This substitutes a thermal/physical process with a chemical bonding mechanism, eliminating the harmful heat generation while maintaining adhesion enhancement.
Solution Approach 2:
The patent introduces an adhesion promoter layer as an intermediary between the hard coating layer and the decoration layer. This intermediate layer chemically bonds to both surfaces, providing strong adhesion without requiring plasma treatment. The intermediary layer acts as a chemical bridge that eliminates the need for harmful plasma processing.
2Strength
If a hard coating process is applied to increase surface hardness, then the surface hardness and chemical resistance are improved, but the adhesion between the hard coating layer and the decoration layer decreases
Solution Approach 1:
The adhesion promoter layer serves as a chemical intermediary that bonds to the hard coating layer on one side and the decoration layer on the other side. This intermediate chemical layer resolves the adhesion problem by providing compatible bonding interfaces with both the hard coating and the decoration materials, without compromising the surface hardness achieved by the hard coating process.
Solution Approach 2:
The patent creates a composite structure consisting of the hard coating layer, the adhesion promoter layer, and the decoration layer. Each layer maintains its specific properties (hardness from the hard coating, bonding capability from the adhesion promoter, and aesthetic properties from the decoration layer), while the composite structure as a whole achieves both surface hardness and strong adhesion.
3Adaptability or versatility
If a printed film is attached to the display window for decoration, then various colors and designs are achieved, but the adhesion between the hard coating layer and the decoration layer is not secure
Solution Approach 1:
The adhesion promoter layer acts as a universal intermediary that provides strong chemical bonding to both the hard coating layer and various decoration materials including printed films. This intermediate layer ensures secure attachment regardless of the specific decoration material used, maintaining reliability while allowing versatility in design choices.
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 enhances the adhesion between the hard coating and decoration layers, preventing peeling-off and ensuring secure attachment, similar to glass windows, while maintaining the transparency and light transmission of plastic substrates.
Implementation Method 1
UV-curable hard coating composition
Data Source
AI summary
A display device includes: a display panel configured to display an image; a window on the display panel, the window having a display area at which the image is displayed and a non-display area around the display area; and a first adhesive layer between the display panel and the window, wherein the window includes: a window substrate on the display panel; a first hard coating layer at a first surface of the window substrate; a second hard coating layer at a second surface of the window substrate opposite to the first surface; a protection layer on the first hard coating layer; an auxiliary adhesive layer on the second hard coating layer; a base film on the auxiliary adhesive layer; and a second adhesive layer between the auxiliary adhesive layer and the base film.