Mutual Capacitive Touch Panel Double-Layer Electrode Background Capacitance
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Solution Overview
Problem
Conventional double-layer electrode touch panels face issues with increased background capacitance due to thinner dielectric layers, leading to loading effects and signal saturation, which degrade the detecting quality.
Innovation Solution
A mutual capacitive touch panel design featuring a first electrode layer, an insulating layer, and a second electrode layer with strategically arranged electrode portions and branch parts, where the spacing between branch parts and the outer side is greater than twice the width of the branch parts, increasing capacitance variation and reducing background capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the dielectric layer thickness is reduced to make the touch panel thinner, then the touch panel thickness is reduced, but the background capacitance increases
Solution Approach 1:
The electrode structure is segmented into multiple components: electrode strings, electrode strips, main parts, and branch parts. This segmentation allows optimization of the electric field distribution by separating the functional regions, thereby reducing background capacitance while maintaining thin panel structure.
Solution Approach 2:
Different regions of the electrode structure are given different properties. The branch parts are positioned at specific locations with specific spacing requirements (greater than twice the width of the branch part) to create optimal local electric field conditions that reduce background capacitance while maintaining overall panel thinness.
2Measurement precision
If the background capacitance is reduced by increasing dielectric layer thickness, then background capacitance decreases, but the touch panel thickness increases
Solution Approach 1:
Instead of solving the background capacitance problem solely in the vertical dimension (dielectric thickness), the invention transitions to the horizontal dimension by optimizing the electrode arrangement, spacing, and geometry. The branch parts extending from main parts create favorable electric field patterns that reduce background capacitance without increasing panel thickness.
3Measurement precision
If the background capacitance is large, then the loading effect on driving string becomes more obvious, but the signal detection accuracy deteriorates
Solution Approach 1:
The invention changes geometric parameters of the electrode structure, specifically the spacing between branch parts and outer sides (set to greater than twice the branch part width), and the arrangement of electrode strings and strips. These parameter changes optimize the electric field distribution to minimize loading effects and reduce background capacitance, thereby improving signal detection accuracy.
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 design enhances capacitance variation and reduces background capacitance, improving the detecting quality by preventing signal saturation and increasing the accuracy of touch detection.
Implementation Method 1
the dielectric layer of the background capacitor between the driving string and the sensing string becomes thinner and thinner
Implementation Method 2
background capacitance between the sensing string and the driving string
Data Source
AI summary
The present invention provides a mutual capacitive touch panel including a first electrode layer and a second electrode layer. The first electrode layer includes a plurality of electrode strings extending along a first direction. The second electrode layer includes a plurality of electrode strips extending along a second direction, in which one of the electrode strips include a plurality of electrode portions connected in series, one of the electrode portions includes a main part and at least branch part, the main part crosses a corresponding one of the electrode strings, the branch part is connected to a side of the main part, and no branch part exists between the branch part and the outer side of the corresponding electrode string. A spacing between a side of the branch part adjacent to the outer side and the outer side is greater than twice a width of the branch part.