Capacitive Touch Panel Impedance Reduction via Segmented Electrode Scanning
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitive touch panels face issues with high impedance leading to signal attenuation and reduced sensitivity, especially at higher scanning frequencies, which affects the signal-to-noise ratio and scanning speed.
Innovation Solution
A capacitive touch panel design featuring a touch sensing pattern with first and second conductive assemblies arranged in perpendicular directions, connected by signal lines that allow for efficient charging and discharging through a common signal source, reducing impedance and signal attenuation, and incorporating a manufacturing method using sputtering, exposing, and etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If scanning frequency is increased to improve scanning speed, then productivity is improved, but impedance increases causing signal attenuation and reduced measurement precision
Solution Approach 1:
The touch panel electrodes are divided into multiple segments along the scanning direction. Each segment is independently connected to the controller, allowing sequential scanning with reduced impedance per segment. This segmentation enables higher scanning frequencies while maintaining signal integrity, as each segment presents lower impedance to the controller compared to a single long electrode.
Solution Approach 2:
The patent introduces a time dimension to the scanning process by implementing sequential scanning of divided electrode segments. Instead of attempting to scan the entire electrode array simultaneously (which would require extremely low impedance), the system scans segments in time sequence, effectively trading spatial complexity for temporal processing and achieving high scanning speeds with maintained signal quality.
2Measurement precision
If impedance is reduced to improve signal to noise ratio, then measurement precision is improved, but device complexity increases due to additional signal lines and conductive assemblies
Solution Approach 1:
Adjacent electrode segments that are not currently being scanned are electrically connected and held at the same potential (ground or reference voltage). This merging of non-active segments reduces the overall impedance presented to the active scanning segment, improving signal to noise ratio without requiring completely separate control circuitry for each segment.
Solution Approach 2:
The controller periodically switches between scanning different electrode segments in a cyclic manner. During each period, one segment is actively scanned while others are held at reference potential. This periodic action allows the use of simpler impedance management techniques compared to continuous simultaneous scanning of all segments, reducing device complexity while maintaining measurement precision.
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 enhances the signal-to-noise ratio, increases scanning speed, and reduces electric consumption by minimizing impedance, thereby improving the reliability and sensitivity of the touch panel.
Implementation Method 1
a manufacturing method using sputtering, exposing, and etching processes
Data Source
AI summary
The present invention discloses a capacitive touch panel, comprises a touch sensing pattern form on a substrate, which could generate a sensing signals in response to a touch on the capacitive touch panel; a plurality of first signal lines and a second signal line for conducting the sensing signals; the touch sensing pattern comprises a plurality of first conductive assemblies arranged in a first direction, a first end of each first conductive assembly respectively connects to a corresponding first signal line; the second signal line connects the second ends of all of the first conductive assemblies together.