Capacitive Multi-Touch Panel With Interleaved Electrodes
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Solution Overview
Problem
Conventional capacitive touch panels exhibit non-uniform response characteristics due to natural variations in electrode patterns, leading to inconsistent signal strength across the panel.
Innovation Solution
The touch panel design features a sensor layer with interleaved row and column electrodes arranged in a logical array to reduce parasitic capacitance and resistance, using a single conductive trace that is transparent to visible light, with an insulator for electrical isolation and a touch panel controller for uniform signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrode patterns are used, then the touch panel can be manufactured with standard processes, but the response characteristic becomes non-uniform across the panel
Solution Approach 1:
The electrode pattern is segmented into interlaced row and column electrodes that are offset from each other. This segmentation allows the formation of multiple smaller sensing regions that collectively provide uniform response characteristics across the entire panel, resolving the contradiction between standard manufacturing and response uniformity.
Solution Approach 2:
The row and column electrodes are arranged in an asymmetric interlaced pattern where column electrodes are positioned between row electrodes rather than directly overlapping them. This asymmetric arrangement eliminates non-overlapping gaps while maintaining manufacturability through standard transparent conductor deposition processes.
2Ease of manufacture
If electrodes are arranged with gaps or non-overlapping regions to simplify manufacturing, then manufacturing is easier, but signal strength varies as objects pass over these regions
Solution Approach 1:
The electrode arrangement transitions from a simple grid to an interlaced three-dimensional configuration where row and column electrodes occupy different spatial positions. This dimensional arrangement ensures continuous electrode coverage across the panel surface, eliminating signal variations while maintaining ease of manufacture through sequential deposition layers.
3Reliability
If traditional multi-layer electrode structures are used, then electrical isolation is achieved, but parasitic capacitance and resistance increase
Solution Approach 1:
The design extracts and eliminates the intermediate dielectric layer traditionally used for electrical isolation between row and column electrodes. Instead, electrical isolation is achieved through the spatial interlacing arrangement and selective conductivity patterns, removing the source of parasitic capacitance while maintaining necessary electrical separation.
Solution Approach 2:
The transparent conductor patterns serve as an intermediary structure that provides both electrical connectivity and isolation functions. By carefully designing the conductivity distribution in the interlaced electrode pattern, the system achieves electrical isolation without requiring additional dielectric layers, thereby reducing parasitic effects.
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 achieves a more uniform response characteristic, reducing parasitic capacitance and resistance by 50%, enhancing manufacturing yield and reducing processing costs by minimizing bonding pad count.
Implementation Method 1
When an object (e.g., finger) is in proximity to the touch panel (which is generally considered to be a touch event), there is a change in capacitance due at least in part to the arrangement of electrodes
Data Source
AI summary
An apparatus is provided. A substrate and a cover plate are provided. A sensor layer is formed on at least one of the substrate and the cover plate. The sensor layer includes a plurality of row electrodes and a plurality of column electrodes interleaved with the plurality of row electrodes, where each row electrode and each column electrode is formed of a plurality of stair-stepped diamonds. An insulator is also included so as to electrically isolate the plurality of row electrodes and the plurality of column electrodes, where the insulator is substantially transparent to visible spectrum light. The apparatus employs mirror symmetric row sensor routing placement.