Touch Sensor Electrode Layout for Moisture-Stable Capacitance
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Solution Overview
Problem
Existing electronic devices face challenges in maintaining reliability due to variations in mutual capacitance between sensor nodes, which can be exacerbated by moisture, leading to reduced accuracy in input detection.
Innovation Solution
The electronic device incorporates a sensor layer with a specific electrode configuration, including sensing patterns, bridge patterns, and dummy patterns, where the ratio of dummy pattern areas to sensing pattern areas is within a defined range (1% to 10%), ensuring proper capacitance balance and insulation, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy patterns are added to the sensor layer, then capacitance balance is improved, but device complexity increases
Solution Approach 1:
Dummy patterns are introduced as intermediary elements between the first electrode and second electrode to balance parasitic capacitance. These dummy patterns act as mediators that compensate for capacitance variations in different sensor nodes, improving measurement accuracy without requiring fundamental changes to the sensor structure.
Solution Approach 2:
The area ratios of dummy patterns are precisely controlled within specific ranges (first dummy pattern area ratio: 10-50%, second dummy pattern area ratio: 50-90%) to adjust and balance the parasitic capacitance values. By changing the geometric parameters of dummy patterns, the patent achieves capacitance compensation while maintaining a relatively simple electrode structure.
2Reliability
If dummy patterns with larger areas are used, then capacitance compensation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for dummy pattern areas to balance capacitance effectively. The first dummy pattern area ratio is set at 10-50% and the second at 50-90%, providing clear manufacturing guidelines that balance capacitance compensation needs with manufacturability. These parameter specifications enable effective capacitance balancing while maintaining reasonable manufacturing precision requirements.
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 stabilizes capacitance levels, improving the device's ability to accurately detect inputs even in moist conditions, maintaining consistent performance and reliability.
Implementation Method 1
a sensor driver configured to drive the sensor layer in a first mode when a mutual capacitance of a node of the sensor layer compared to a mutual capacitance of another node that is adjacent to the node is outside a ratio range
Data Source
AI summary
Disclosed is an electronic device which includes a display layer, a sensor layer above the display layer, and a sensor driver configured to drive the sensor layer in a first mode when a mutual capacitance of a node of the sensor layer compared to a mutual capacitance of another node that is adjacent to the node is outside a ratio range, wherein the sensor layer includes a first electrode including sensing patterns and a bridge pattern, a second electrode including first parts and a second part, and a dummy electrode including dummy patterns, wherein a first area of one of the dummy patterns is less than a second area of one of the first parts, and wherein a ratio of the first area to the second area satisfies the ratio range.