Capacitive Touch Screen Electrode Design for Parasitic Capacitance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electrostatic capacitive touch screen panels suffer from reduced touch sensitivity due to high parasitic capacitance and low variation rate of mutual capacitance, which affects the charge characteristic and overall performance.
Innovation Solution
The design includes touch electrodes with extended branch portions and concaves, increasing the total length of edges and incorporating dummy electrodes to reduce parasitic capacitance and enhance mutual capacitance, thereby improving charge characteristics and touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional touch electrode patterns are used, then the structure is simple, but parasitic capacitance is high and touch sensitivity is reduced
Solution Approach 1:
The touch electrodes are divided into multiple segments with stem portions and branch portions, where each branch portion extends in different directions. This segmentation increases the total edge length and mutual capacitance while maintaining manageable structural complexity through systematic arrangement of the divided elements.
Solution Approach 2:
The electrode patterns are designed with three-dimensional considerations by creating concaves and having branch portions extend in multiple directions (upward, downward, leftward, rightward). This multi-directional extension increases the effective edge length and mutual capacitance without proportionally increasing the planar area occupation.
2Measurement precision
If electrode edge length is increased to improve mutual capacitance, then touch sensitivity improves, but parasitic capacitance increases
Solution Approach 1:
Dummy electrodes are strategically placed in specific regions (such as corner regions) where they can effectively reduce parasitic capacitance. The local addition of these dummy elements targets the harmful parasitic capacitance without adding to the mutual capacitance measurement path, thereby improving touch sensitivity while reducing parasitic effects.
Solution Approach 2:
The dummy electrodes are designed to convert the harmful parasitic capacitance into a beneficial effect by reducing the overall parasitic capacitance of the touch screen panel. These additional electrode elements, while extending the total electrode structure, are positioned and configured to specifically counteract parasitic capacitance rather than increase it.
3Use of energy by moving object
If charge characteristic is improved by reducing parasitic capacitance, then touch sensitivity improves, but electrode design becomes more complex
Solution Approach 1:
The electrode structure is segmented into standardized stem and branch portions that can be systematically repeated across different regions of the touch screen. This modular segmentation allows for improved charge characteristics through increased edge length while keeping the design process manageable through repetition of standardized elements rather than creating entirely unique complex patterns.
Solution Approach 2:
The electrode design optimizes parameters such as the number of branch portions, their extension directions, and the positioning of concaves to achieve optimal charge characteristics. By systematically varying these parameters (e.g., extending branches in four directions, creating specific concave positions), the design achieves improved mutual capacitance and reduced parasitic capacitance without requiring overly complex arbitrary patterns.
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 enhances touch sensitivity by increasing mutual capacitance and reducing parasitic capacitance, leading to improved charge characteristics and performance of the touch screen panel.
Implementation Method 1
The capacitive type touch screen panel senses a touched position according to a difference in capacitance created in an upper or lower plate when the user touches an equipotential conductive film formed on the upper or lower plate
Implementation Method 2
The electromagnetic type touch screen panel detects a touched position by reading an LC value induced as an electromagnetic pen touches a conductive film
Data Source
AI summary
A touch screen panel includes a plurality of first touch electrode serials arranged in a first direction and a plurality of second touch electrode serials arranged in a second direction crossing over the first direction, and electrically insulated from the plurality of first electrode serials. The first touch electrode serial includes a plurality of first touch electrodes connected in serial, and the second touch electrode serial includes a plurality of second touch electrodes connected in serial. The first touch electrode has a first stem portion, and a plurality of first branch portions outwardly extended from both sides of the first stem portion. The second touch electrodes has a second stem portion, and a plurality of second branch portions outwardly extended from both sides of the second stem portion.