Touch Display Electrode Layout for Parasitic Capacitance Reduction
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Solution Overview
Problem
Current capacitive touch screens face issues with parasitic capacitance between the detection electrode and the common electrode, which affects the quality of touch sensing signals and the touch induction capacitance change rate.
Innovation Solution
The design involves a touch display device with a first substrate having a common electrode and a driving electrode alternately arranged, and a second substrate with a detection electrode and a suspension electrode, where the detection electrode's coverage area is smaller than the common electrode's, and the suspension electrode is insulated from the detection electrode, reducing parasitic capacitance and improving touch sensing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection electrode coverage area is increased to improve touch sensing signal quality, then the touch sensitivity is improved, but the parasitic capacitance between the detection electrode and common electrode increases
Solution Approach 1:
The electrode structure is segmented into distinct functional zones: the detection electrode coverage area is intentionally made smaller than the common electrode coverage area, creating a non-overlapping region. This segmentation separates the touch sensing function from the common electrode function, allowing the detection electrode to maintain adequate coverage for sensitivity while reducing the overlapping area that generates parasitic capacitance.
Solution Approach 2:
Different regions of the electrode structure are given different properties: the detection electrode is positioned to have optimal coverage for touch sensing in specific areas, while deliberately reducing coverage in areas where it would overlap with the common electrode. This local optimization ensures high touch sensitivity where needed while minimizing parasitic capacitance in overlapping regions.
2Ease of manufacture
If the overlapping area between detection electrode and common electrode is increased to improve manufacturing simplicity, then the manufacturing process is simplified, but the parasitic capacitance increases affecting touch sensing accuracy
Solution Approach 1:
The electrode structure employs asymmetric design where the detection electrode coverage area is deliberately made unequal to the common electrode coverage area. The detection electrode is positioned within a smaller boundary than the common electrode, creating an asymmetric overlapping pattern that reduces parasitic capacitance while maintaining manufacturing feasibility through standard patterning processes.
3Object-generated harmful factors
If the detection electrode coverage area is reduced to reduce parasitic capacitance, then the parasitic capacitance decreases, but the touch sensing signal quality deteriorates
Solution Approach 1:
The electrode design dynamically balances coverage area against parasitic capacitance by creating a specific geometric relationship where the detection electrode coverage is optimized to be smaller than the common electrode coverage. This dynamic optimization ensures that the detection electrode maintains sufficient area for adequate touch sensing while the reduced overlapping area with the common electrode minimizes parasitic capacitance effects.
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 reduces parasitic capacitance and enhances the touch induction capacitance change rate, ensuring better quality of touch sensing signals and improving the performance of capacitive touch screens.
Implementation Method 1
parasitic capacitance between the detection electrode and the common electrode
Implementation Method 2
the second substrate is further provided with a suspension electrode, and the suspension electrode is arranged on at least one side of the detection electrode and insulated from the detection electrode
Data Source
AI summary
The present disclosure provides a touch display device and a method for manufacturing the same. The touch display device includes a first substrate and a second substrate. The first substrate is provided with a common electrode and a driving electrode. The second substrate is provided with a detection electrode and a driving electrode. The detection electrode is opposite to the common electrode. A coverage area of the detection electrode is smaller than a coverage area of the common electrode, the coverage area of the detection electrode on the second substrate does not overlap with a coverage area of the driving electrode on the first substrate when the first substrate and the second substrate are assembled to form a cell. The suspension electrode is arranged on at least one side of the detection electrode and insulated from the detection electrode.