Touch Panel Electrode Winding for Sensing Accuracy
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Solution Overview
Problem
The thinning or omission of the cover lens in touch panels leads to errors in response points due to increased self capacitance values after touch, causing incorrect sensing.
Innovation Solution
A touch panel design featuring a substrate with isolated first and second electrodes, where the covering layer is positioned close to the electrodes, reducing mutual and self capacitance values, and the electrodes are wound to minimize area and increase allowed self capacitance increase time, preventing error response points even when the cover lens is thinned or omitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the cover lens is thinned or omitted to achieve a thinner and more compact touch panel, then the panel thickness is reduced, but error response points occur due to increased self capacitance values
Solution Approach 1:
The patent changes the physical parameters of the electrodes by winding them into spiral patterns and reducing their area. This parameter modification reduces the self-capacitance values of the electrodes, allowing the cover lens to be thinned or omitted while preventing error response points. The winding structure transforms the electrode geometry from flat extended surfaces to compact spiral forms with smaller effective areas.
Solution Approach 2:
The patent applies curvature by winding the electrodes into spiral patterns rather than using flat linear traces. This spiral configuration reduces the electrode area while maintaining electrical functionality, thereby reducing self-capacitance and preventing sensing errors when the cover lens is thinned or removed.
2Device complexity
If the cover lens is thinned or omitted, then the panel becomes more compact, but the allowed self capacitance increase time decreases causing error response points
Solution Approach 1:
The patent modifies the electrode parameters by reducing their area through winding, which directly reduces self-capacitance values. This parameter change extends the allowed self-capacitance increase time, preventing error response points while maintaining the simplified panel structure without a thick cover lens.
Solution Approach 2:
The patent segments the electrode structure into multiple spiral turns rather than using a single continuous flat trace. This segmentation into spiral segments reduces the overall electrode area and self-capacitance, allowing the system to tolerate longer capacitance increase times even when the cover lens is thinned or omitted.
3Reliability
If the electrode area is increased to reduce self capacitance values, then self capacitance decreases, but the panel area occupied by electrodes increases
Solution Approach 1:
The patent uses spiral winding of electrodes to achieve a compact configuration that reduces the effective electrode area. The curved spiral path allows the electrode to occupy less planar space while maintaining sufficient capacitance for operation, solving the contradiction between reducing self-capacitance and minimizing panel area occupation.
Solution Approach 2:
The electrode is nested into a spiral pattern where the conductive trace winds around a central point, creating a compact nested structure. This nesting approach reduces the bounding box area of the electrode while maintaining the necessary trace length and electrical properties, thereby reducing self-capacitance without proportionally increasing the occupied panel area.
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 design effectively reduces self capacitance values and increases the allowed self capacitance increase time, preventing error response points and ensuring accurate sensing regardless of the cover lens thickness.
Implementation Method 1
a mutual capacitance value between the first electrode and the second electrode ranges between 0.1 pF and 10 pF when a touch has not occurred yet
Data Source
AI summary
A touch panel may include a substrate, a touch unit region and a covering layer. The touch unit region includes first electrode and a second electrode isolated from the first electrode. The covering layer covers at least one of the first electrode and the second electrode and has a touch surface. A distance between the touch surface and the first electrode or the second electrode ranges between 0.01 micrometers and 100 micrometers. A mutual capacitance value between the first electrode and the second electrode ranges between 0.1 pF and 10 pF when a touch has not occurred yet.