Touch Panel Common Electrode Segmentation for Parasitic Capacitance Reduction
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Solution Overview
Problem
Conventional touch panels suffer from poor touch detection accuracy due to parasitic capacitance between touch wires and common electrode blocks, which reduces the reliability of touch electronic devices.
Innovation Solution
The touch panel design includes common electrode blocks arranged in the same layer as touch wires with gaps, where each gap is bridged by a first and second common electrode sub-block connected through a bridge electrode, reducing parasitic capacitance and improving touch detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common electrode blocks are arranged in the same layer as touch wires, then the parasitic capacitance between touch wires and common electrode blocks increases, but this arrangement simplifies the manufacturing process and reduces the number of layers
Solution Approach 1:
The common electrode block is divided into multiple isolated electrode segments by introducing gaps. These segmented electrodes are arranged in the same layer as touch wires, reducing the continuous parasitic capacitance while maintaining manufacturing simplicity. The segmentation breaks the large electrode into smaller units with reduced capacitive coupling to adjacent touch wires.
Solution Approach 2:
Gaps are extracted from the common electrode block structure to create isolated electrode segments. This extraction removes the harmful parasitic capacitance portions while retaining the essential common electrode functionality, allowing the electrode to coexist in the same layer as touch wires without degrading touch detection accuracy.
2Measurement precision
If gaps are introduced in common electrode blocks to reduce parasitic capacitance, then touch detection accuracy improves, but the manufacturing precision requirements increase
Solution Approach 1:
Gaps are strategically positioned only in specific regions where parasitic capacitance is most problematic, rather than uniformly distributing gaps throughout the entire electrode structure. This localized approach reduces parasitic capacitance in critical areas while minimizing the overall number of gaps, thereby reducing manufacturing precision requirements.
Solution Approach 2:
The gap configuration employs asymmetric design where gaps are placed selectively based on the specific wiring layout and parasitic capacitance distribution patterns. This asymmetric arrangement optimizes parasitic capacitance reduction while accommodating manufacturing tolerances, as not all electrode regions require identical gap treatment.
Data Source
AI summary
A touch panel includes multiple common electrode blocks arranged in an array and multiple touch wires. Each of the touch wires is electrically connected to corresponding one of the common electrode blocks and is insulated from other common electrode blocks that are insulated from the one of the touch wire. The other common electrode blocks are in the same layer with the touch wire. There is a gap in a common electrode block that is located at a path of the touch wire and that is insulated from the touch wire. The common electrode block that is electrically connected to the touch wire comprises a first and a second common electrode sub-blocks, both of which are adjacent to the gap. The first common electrode sub-block is connected to the second common electrode sub-block through at least one bridge electrode.