Capacitive Touch Panel with Rough Protective Sheet to Stop Newton's Rings
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Solution Overview
Problem
Capacitive touch panels with a single transparent substrate experience Newton's rings when attached to large display units, leading to bending or distortion and reduced brightness due to insufficient transparency of conventional anti-Newton ring films.
Innovation Solution
A capacitive touch panel configuration with a transparent substrate and a protective sheet having a surface roughness of 1.5 nm to 400 nm, which reduces the occurrence of Newton's rings and enhances the brightness of the touch surface by minimizing adhesion to the display unit's polarizing plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single transparent substrate type capacitive touch panel is used, then the weight and thickness are reduced, but Newton's rings occur and bending or distortion happens
Solution Approach 1:
A protective sheet with specific surface roughness (0.003-0.04 μm) is introduced as an intermediary layer between the transparent substrate and the display unit. This protective sheet acts as a mediator that prevents direct contact and adhesion between the touch panel and display unit, thereby eliminating Newton's rings while maintaining the lightweight single-substrate structure
Solution Approach 2:
The surface roughness of the protective sheet is precisely controlled within the range of 0.003-0.04 μm. This parameter change creates optimal conditions for preventing adhesion and Newton's rings formation, while the protective sheet material and surface properties are optimized to maintain high transparency and prevent distortion
2Reliability
If conventional anti-Newton ring films are used, then Newton's rings are prevented, but transparency is reduced and brightness decreases
Solution Approach 1:
The surface roughness of the protective sheet is precisely controlled within the range of 0.003-0.04 μm, which is optimized to prevent Newton's rings formation through reduced adhesion. This parameter optimization allows the protective sheet to maintain high transparency, unlike conventional anti-Newton ring films that require thicker or more opaque materials
Solution Approach 2:
The protective sheet serves as a thin, transparent protective layer that can be easily applied and removed if needed. Its specific surface roughness provides durable Newton's ring prevention without compromising the underlying transparent substrate, offering a cost-effective solution that maintains optical clarity
3Strength
If the touch panel is brought into contact with the display unit, then adhesion is strong, but Newton's rings and blocking occur
Solution Approach 1:
The protective sheet with controlled surface roughness (0.003-0.04 μm) serves as an intermediary layer between the transparent substrate and the display unit. This intermediary prevents direct contact and adhesion, thereby eliminating Newton's rings and blocking while still providing sufficient mechanical support and protection
Solution Approach 2:
The protective sheet introduces surface curvature at the microscopic level through its specific roughness profile. This curvature prevents flat contact between the touch panel and display unit, reducing adhesion points and eliminating the conditions for Newton's rings formation while maintaining overall structural integrity
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 effectively prevents Newton's rings and maintains high transparency, ensuring a clear and functional touch surface on large display units.
Implementation Method 1
Capacitive touch panels with a single transparent substrate experience Newton's rings when attached to large display units
Implementation Method 2
a protective sheet which is laminated on the conductive layer via an adhesive layer, wherein the protective sheet has a surface having a surface roughness of 1.5 nm to 400 nm
Data Source
AI summary
A display device with a capacitive touch panel including a liquid crystal display having a polarizing plate disposed on a top surface thereof; and a capacitive touch panel which is disposed in front of the liquid crystal display such that a gap is provided between the touch panel and the polarizing plate, and has an outer edge which is fixed to the liquid crystal display via an adhesive layer therebetween. The touch panel includes a transparent substrate, a conductive layer which is provided on the side of the liquid crystal display of the transparent substrate, and a protective sheet which is laminated on the conductive layer via an adhesive layer, and a surface of the protective sheet opposed to the liquid crystal display is an irregular surface having minute irregularities, and the irregular surface has a surface roughness of 1.5 nm to 400 nm.