Position Detecting Sensor Asymmetric Mesh Electrode Design
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Solution Overview
Problem
Position detecting sensors using metallic mesh electrodes face challenges in maintaining linearity of detection accuracy when using a stylus, as insufficient coupling capacitance can lead to deviations in detected positions, and widening electrodes to improve accuracy obstructs electrostatic coupling.
Innovation Solution
The position detecting sensor is designed with first and second electrodes formed in a mesh form, where the width and mesh density of the first electrodes differ from those of the second electrodes, ensuring sufficient and flat coupling capacitances for improved detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the width of the first electrodes is widened to improve detection accuracy by increasing coupling capacitance, then the coupling capacitance between the stylus and first electrodes increases, but the first electrodes obstruct the electrostatic coupling between the stylus and second electrodes to a greater extent, causing degradation in linearity of detection accuracy
Solution Approach 1:
The patent applies local quality by making the first and second electrodes have different widths. Specifically, the first electrodes (on the operating surface side) have a width of 5-10 μm, while the second electrodes (on the lower side) have a width of 15-20 μm. This asymmetric design allows the first electrodes to provide sufficient coupling capacitance for accurate stylus detection while keeping them narrow enough to minimize obstruction of electrostatic coupling to the second electrodes, thus maintaining linearity of detection accuracy.
2Illumination intensity
If the position detecting sensor uses metallic mesh electrodes to achieve good transparency and low resistance, then transparency and conductivity are improved, but insufficient coupling capacitance causes deviation in detected position and degradation in linearity
Solution Approach 1:
The patent applies parameter changes by optimizing the width parameters of the metallic mesh electrodes. The first electrodes have a width of 5-10 μm and the second electrodes have a width of 15-20 μm. These specific width parameters enable the metallic mesh electrodes to maintain both good transparency and sufficient coupling capacitance, resolving the contradiction between transparency and detection linearity.
3Device complexity
If the second electrodes are located on the lower side of the first electrodes, then the laminated structure is formed, but the stylus and second electrodes are electrostatically coupled through interstices between the first electrodes as shielding objects, resulting in low coupling capacitance
Solution Approach 1:
The patent applies asymmetry by making the widths of the first and second electrodes different. The first electrodes have a width of 5-10 μm while the second electrodes have a width of 15-20 μm. This asymmetric design compensates for the shielding effect of the first electrodes on the electrostatic coupling between the stylus and second electrodes, ensuring sufficient coupling capacitance is maintained despite the laminated structure.
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 maintains high coupling capacitance between the stylus and electrodes, enhancing the linearity of stylus detection and enabling precise minute indication inputs, while preventing obstruction of electrostatic coupling.
Implementation Method 1
the stylus and an electrode with which the stylus comes into proximity are electrostatically coupled to each other, a voltage is induced in the electrode, and thus a signal appears in the electrode
Implementation Method 2
a coupling capacitance therebetween is high... coupling capacitances between the stylus SR and the second electrodes b1, b2, . . . may be low
Data Source
AI summary
A position detecting sensor includes a plurality of first electrodes arranged in a first direction; and a plurality of second electrodes arranged in a second direction intersecting the first direction. The plurality of first electrodes and the plurality of second electrodes are formed in a mesh form. One or both of: (i) a width of each of the plurality of first electrodes in an arrangement direction of the plurality of first electrodes is different from a width of each of the plurality of second electrodes in an arrangement direction of the plurality of second electrodes, and (ii) a mesh density of each of the plurality of first electrodes is different from a mesh density of each of the plurality of second electrodes.