Deformed Dummy Electrodes Reduce Base Capacitance in Touch Sensor Panels
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Solution Overview
Problem
The inclusion of dummy electrodes in touch sensor panels increases the base capacitance, leading to reduced touch sensitivity, especially when their patterns overlap with those of the common electrodes.
Innovation Solution
Incorporating deformed dummy drive electrodes and/or dummy receiving electrodes, which are spaced apart from the drive and receiving electrodes, thereby blocking a part of the capacitance path to reduce the base capacitance and enhance sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If dummy electrodes are included in the touch sensor panel, then the coverage area is improved, but the base capacitance increases and touch sensitivity is reduced
Solution Approach 1:
The dummy electrodes are divided into multiple segments along their extension direction. Each segment is electrically isolated from others, creating discrete capacitance regions. This segmentation reduces the continuous capacitance path that would otherwise form between overlapping dummy electrodes and common electrodes, thereby reducing base capacitance while preserving the coverage area provided by the dummy electrode structure.
Solution Approach 2:
The dummy electrodes are configured with non-uniform properties: they have different widths, spacing, or deformation characteristics at different positions along their extension direction. This allows the capacitance contribution to be optimized locally - regions with higher overlap with common electrodes have reduced capacitance through segmentation or spacing, while regions with less overlap maintain better signal characteristics.
2Device complexity
If dummy electrodes overlap with common electrodes, then the structural integration is improved, but the base capacitance considerably increases
Solution Approach 1:
By segmenting the dummy electrodes into multiple isolated sections, the continuous capacitance coupling between overlapping dummy and common electrodes is broken into discrete, smaller capacitance elements. This maintains the structural integration and overlapping layout while significantly reducing the total base capacitance contribution from the overlap regions.
Solution Approach 2:
Insulating layers or spacing structures are introduced between the dummy electrodes and common electrodes in overlapping regions. These intermediary elements maintain the structural integration and close proximity needed for manufacturing efficiency, while electrically isolating the conductive elements to prevent excessive capacitance coupling.
3Quantity of substance
If dummy electrodes are spaced apart from drive and receiving electrodes, then the base capacitance is reduced, but the device complexity increases
Solution Approach 1:
The spacing and positioning of dummy electrodes are integrated into the overall electrode pattern design from the beginning, rather than being added as separate features. The dummy electrodes share the same manufacturing process, material layers, and design rules as the drive and receiving electrodes, merging their implementation to avoid increasing device complexity despite the additional structural elements.
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 deformation of dummy electrodes effectively reduces the base capacitance, improving touch sensitivity by minimizing unnecessary capacitance and maintaining operational efficiency.
Implementation Method 1
A part of a capacitance path between the drive electrode and the receiving electrode is blocked
Data Source
AI summary
A touch sensor panel may be provided that includes: a plurality of drive electrodes which extend in a first layer in a first axial direction and sense touch; a plurality of dummy drive electrodes which extend in the first layer in the first axial direction and do not sense the touch; a plurality of receiving electrodes which extend in a second layer in a second axial direction crossing the first axial direction and sense the touch; and a plurality of dummy receiving electrodes which extend in the second layer in the second axial direction and do not sense the touch. A part of a capacitance path between the drive electrode and the receiving electrode is blocked.