Capacitive Touch Panel Layout for Higher Sensitivity and Noise Shielding
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Solution Overview
Problem
Current capacitive touch panels face challenges in achieving high touching sensitivity due to interference from grounded objects, which affects the detection of touch coordinates and results in a low signal-to-noise ratio (SNR) and high equivalent resistance.
Innovation Solution
The capacitive touch panel design includes intersecting first and second conductor lines with defined overlapping regions, where each overlapping region has a first mutual capacitance without contact and a second mutual capacitance with contact, and features openings in the first conductor lines to increase the change in mutual capacitance, enhancing sensitivity and noise shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional capacitive touch panel structure with continuous conductor lines is used, then the panel can detect touch coordinates, but the signal-to-noise ratio is low and touching sensitivity is insufficient due to interference from grounded objects
Solution Approach 1:
The continuous conductor lines are segmented into discrete electrode plates arranged in arrays. The first array of conductor lines and second array of conductor lines are separated by insulating layers, creating distinct capacitive sensing regions. This segmentation isolates the electric fields, reducing interference from grounded objects and improving signal-to-noise ratio for touch coordinate detection.
Solution Approach 2:
The patent transitions from a single-layer conductor structure to a multi-layer three-dimensional arrangement. Conductor lines are disposed on different sides of insulating layers, creating overlapping regions that form capacitive sensors. This dimensional change allows for better field confinement and reduced susceptibility to external interference while maintaining detection accuracy.
2Measurement precision
If overlapping regions between conductor lines are increased to enhance mutual capacitance, then touch sensitivity improves, but equivalent resistance increases
Solution Approach 1:
The patent applies different properties to different regions: overlapping regions have high mutual capacitance for sensitivity, while non-overlapping regions maintain lower resistance. The conductor lines are designed with varying geometries in different areas to optimize local electrical characteristics, achieving both high touch sensitivity and acceptable equivalent resistance overall.
Solution Approach 2:
The patent designs the conductor line geometries and spacing to create equipotential regions that balance capacitance and resistance. By carefully controlling the overlap areas and insulating layer thickness, the system achieves uniform electrical characteristics across the touch panel, improving both sensitivity and resistance performance.
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 design improves the signal-to-noise ratio (SNR) and reduces equivalent resistance by increasing the change proportion of mutual capacitance, allowing for more accurate touch coordinate detection and effective noise shielding.
Implementation Method 1
Each overlapping region has a mutual capacitance which equals to a first mutual capacitance when the grounded object does not touch the capacitive touch panel and equals to a second mutual capacitance when the grounded object touches the capacitive touch panel
Data Source
AI summary
A capacitive touch panel has a plurality of first conductor lines and a plurality of second conductor lines. The first conductor lines are disposed in a first direction for sensing a contact with an object. The second conductor lines are disposed in a second direction to be intersected insulatively with the first conductor lines so as to define an overlapping region at each intersection of a first conductor line and a second conductor line. As a driving signal is applied to one of the second conductor lines, the overlapping region defined at the intersection forms a capacitance. Each of the first conductor lines defines at least one opening in each of the overlapping regions.