Transparent Capacitive Touch Sensor With Interlaced Nanowire Matrix
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Solution Overview
Problem
Conventional transparent capacitive touch sensors face signal attenuation due to narrowed ITO sensing electrodes and signal paths, which is particularly problematic for large-sized touch panels, as they increase impedance and hinder signal transmission.
Innovation Solution
The implementation of a transparent capacitive touch sensor structure comprising interlacing first and second sensing layers with nanoscale wires made of low-resistivity materials like gold, silver, or copper, separated by an insulative layer, forming a grid-shaped sensing matrix to reduce planar resistance and enhance signal transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If ITO sensing electrodes and signal paths are narrowed to achieve compactness and precision, then device size is reduced, but impedance increases and signal transmission deteriorates
Solution Approach 1:
The patent changes the material parameter from conventional ITO to low-resistivity materials (gold, silver, copper, aluminum, molybdenum, nickel or alloys) with electrical resistivity below 8×10^-8 Ω·m. This parameter change allows the signal paths to maintain narrow dimensions (width less than 25 μm) while achieving sufficiently low impedance for reliable signal transmission in large-sized touch panels.
2Illumination intensity
If transparent conductive films are used to maintain visibility, then transmittance is preserved, but planar resistance increases and signal attenuation worsens
Solution Approach 1:
The patent employs composite material structure where transparent conductive films (maintaining transmittance) are combined with low-resistivity metal materials (reducing planar resistance). The signal paths use metals like gold, silver, copper, aluminum, molybdenum, or nickel with resistivity below 8×10^-8 Ω·m, while the transparent sensing layers maintain optical clarity. This composite approach simultaneously achieves high transmittance and low signal attenuation.
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
This configuration significantly improves the sensitivity and transmission efficiency of touch signals while maintaining high transmittance, making it suitable for large-sized displays without affecting visibility.
Implementation Method 1
Each first wire electrically connects to one of the first contacts and a string of the first sensing units. Each second wire electrically connects to one of the second contacts and a string of the second sensing units. Electrical resistivity of each of the first and second wires is below 8×10−8 Ω·m.
Implementation Method 2
The transparent insulative layer is arranged between the first sensing layer and the second sensing layer to insulatively separate the two sensing layers.
Data Source
AI summary
A capacitive touch sensor includes two sensing layers. Each sensing layer has sensing strings, each of which is composed of sensing units connected in series. An end of each sensing string is provided with a contact. Each sensing string has a wire. Each wire electrically connects to one of the contacts and a string of the sensing units. A transparent insulative layer is arranged between the two sensing layers. The two groups of sensing strings on two the sensing layers interlace with each other to form a sensing matrix.