Touch Sensor Electrode Area Optimization for Parasitic Capacitance Reduction
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Solution Overview
Problem
Conventional touch sensors on display devices face challenges in achieving high detection sensitivity and accuracy due to parasitic capacitance issues, which affect the sensitivity of touch position detection and signal-to-noise ratio.
Innovation Solution
The design incorporates a touch sensor with first and second electrodes arranged in a specific pattern, where the area of each electrode is optimized to satisfy the equation 0.042A≤SA<0.063A, and the electrodes are shaped as triangles or polygons to minimize parasitic capacitance and enhance detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the electrode area is increased to improve touch detection sensitivity, then the signal strength increases, but the parasitic capacitance increases which degrades detection accuracy
Solution Approach 1:
The patent applies parameter changes by optimizing the electrode area to satisfy the specific equation 0.042A ≤ S < 0.063A, where S is the electrode area and A is the total length of electrode sides. This mathematical constraint balances the competing requirements of sufficient signal strength (requiring larger area) and minimal parasitic capacitance (requiring smaller area), resolving the technical contradiction through precise parameter control.
2Device complexity
If conventional touch sensor electrode arrangements are used, then the structure is simple, but the signal-to-noise ratio is poor due to parasitic capacitance
Solution Approach 1:
The patent changes the geometric parameters of the electrode arrangement by specifying that electrodes must satisfy the area-to-perimeter ratio equation 0.042A ≤ S < 0.063A. This parameter optimization improves the signal-to-noise ratio by minimizing parasitic capacitance while maintaining adequate signal strength, without requiring complex multi-layer or three-dimensional electrode structures.
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 improves the sensitivity and accuracy of touch detection by reducing parasitic capacitance and optimizing the area-to-length ratio of the electrodes, leading to better signal detection and higher response rates.
Implementation Method 1
a touch sensor structured by a triangle electrode and a rectangular electrode arranged so as to cross a screen. In this touch sensor, one of the coordinates of a touch position is determined by using a gradient of an electric field generated by the triangle electrode.
Data Source
AI summary
Provided is a display device including a plurality of pixels and a touch sensor overlapping with the plurality of pixels, the touch sensor. The touch sensor possesses: a first wiring arranged in a first direction and including a plurality of first electrodes; and a second wiring arranged in a second direction intersecting the first direction and including a plurality of second electrodes. Each of the first electrodes and each of the second electrodes vary in width continuously or stepwise in the first direction and the second direction, respectively, and satisfy a certain relationship with respect to an area and a total length of sides thereof.