Touch Panel Protective Layer Segmentation for Transparency
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Solution Overview
Problem
The thickness difference between the shielding layer and the sensing electrode layer in touch panels leads to non-uniformity and color differences in the protective layer, affecting the transparency of the touch panel.
Innovation Solution
The protective layer is designed with two distinct portions, one covering the sensing electrode layer and the other the shielding layer, allowing independent formation and minimizing the impact of thickness differences, with the first portion having a refractive index equal to or greater than the sensing electrode layer for improved transparency and the second portion providing reliable adhesion to the shielding layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single protective layer is formed over both the shielding layer and sensing electrode layer, then the structure is simple, but the thickness difference causes non-uniform coating and color differences
Solution Approach 1:
The protective layer is divided into two separate portions: a first protective layer formed over the sensing electrode layer in the display area, and a second protective layer formed over the shielding layer in the non-display area. This segmentation allows each protective layer to be independently optimized for its respective substrate, eliminating the non-uniformity and color differences that would occur with a single protective layer covering both thick and thin areas.
Solution Approach 2:
Different protective layers are applied to different areas based on local requirements. The first protective layer is optimized for the thin sensing electrode layer area where transparency is critical, while the second protective layer is optimized for the thick shielding layer area where adhesion is critical. This local differentiation resolves the contradiction between structural simplicity and coating uniformity.
2Ease of manufacture
If the protective layer is formed uniformly over the thickness step, then the process is simple, but color differences appear affecting transparency
Solution Approach 1:
The protective layer is segmented into two portions formed in separate processes: the first protective layer is formed over the sensing electrode layer, and the second protective layer is formed over the shielding layer. This segmentation allows each layer to be deposited under optimized conditions for its specific area, preventing color differences and maintaining transparency in the display area while ensuring proper adhesion in the non-display area.
Solution Approach 2:
Different deposition parameters are used for forming the first and second protective layers. The first protective layer uses parameters optimized for thin-film deposition to maintain transparency, while the second protective layer uses parameters optimized for adhesion to the thick shielding layer. This parameter differentiation eliminates color differences while maintaining manufacturing feasibility.
3Adaptability or versatility
If a single protective layer is used, then material selection is limited, but the dual-portion design allows different materials optimized for each area
Solution Approach 1:
The protective layer is divided into two distinct portions that can be made of different materials. The first protective layer can be made of a material optimized for optical properties (such as high transparency), while the second protective layer can be made of a material optimized for adhesion to the shielding layer. This material differentiation is enabled by the segmented structure.
Solution Approach 2:
The protective system uses composite materials with different properties for different areas. The first protective layer uses materials selected for optical performance in the display area, while the second protective layer uses materials selected for mechanical adhesion in the non-display area. This composite approach maximizes the benefits of material diversity.
Data Source
AI summary
A touch panel and a fabricating method thereof are provided in the instant disclosure. The touch panel having a non-display area and a display area includes a shielding layer disposed on a side of a substrate and defining the non-display area on the substrate; a sensing electrode layer disposed on the substrate at the same side as the shielding layer, wherein at least one portion of the sensing electrode layer is disposed on a surface of the substrate in the display area; a first protecting layer disposed in the display area and covering the sensing electrode layer; and a second protecting layer disposed in the non-display area and covering the shielding layer. By modifying the structure of the protecting layer, the height difference between the sensing electrode layer and the shielding layer may not cause the color difference due to the non-uniform protecting layer.