Touch Panel Electrode Asymmetry for Stylus Detection
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Solution Overview
Problem
Existing touch panels experience erroneous detection when using a stylus pen with a finer tip end than a finger, due to differences in detection sensitivity between the first and second electrode layers.
Innovation Solution
A touch panel design with a transparent insulating member, a first electrode layer on one surface, and a second electrode layer on the opposing surface, where the occupation ratio of non-connecting wires in the first electrode layer is greater than in the second electrode layer, ensuring C2 < C1, and both layers have the same electrode width, with wire widths of 10 μm or less, to uniformize detection sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the resistance of detection electrode is reduced using thin metallic wires, then detection sensitivity for fine tip ends is improved, but erroneous detection occurs when detecting touch by fine tip ends
Solution Approach 1:
The patent applies local quality by making the first electrode layer have a higher occupation ratio of non-connecting wires (C1) compared to the second electrode layer (C2), where C1 > C2. This creates asymmetric electrode structures with different local densities of non-connecting wires, allowing the touch panel to differentiate between finger touches and fine tip end touches. The first electrode layer's higher density of non-connecting wires provides better sensitivity for fine tips while the asymmetric structure prevents erroneous detection.
2Measurement precision
If non-connecting wires are added to adjust initial electrostatic capacitance, then detection sensitivity is improved, but erroneous detection is generated in fine tip end detection
Solution Approach 1:
The patent applies asymmetry by creating different occupation ratios of non-connecting wires between the first and second electrode layers. Specifically, the first electrode layer has a higher occupation ratio (C1) than the second electrode layer (C2). This asymmetric configuration allows the touch panel to achieve high detection sensitivity for fine tip ends while preventing erroneous detection, as the asymmetric wire distribution creates distinct electrostatic capacitance patterns for different touch types.
3Measurement precision
If electrode wires are made thinner to reduce resistance, then detection sensitivity for fine tips is improved, but visibility of electrode wires increases
Solution Approach 1:
The patent applies parameter changes by optimizing the wire width to be 10 μm or less, which reduces the resistance of detection electrodes and improves detection sensitivity for fine tip ends. Additionally, the patent adjusts the occupation ratio of non-connecting wires (making C1 > C2) to enhance sensitivity while the thin wire design itself helps reduce visibility issues compared to thicker wires.
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 effectively suppresses erroneous detection even with stylus pens having a tip end finer than a finger by ensuring uniform detection sensitivity across the touch panel, improving accuracy and reducing visibility of the electrode wires.
Implementation Method 1
the resistance of a detection electrode that detects a touch can be reduced in electrostatic capacitance-type touch panels
Data Source
AI summary
A touch panel has a transparent insulating member, a first electrode layer, and a second electrode layer, in which in a case where a total area of first non-connecting wires in a first electrode of the first electrode layer is A1, a total area of first electrode wires in the first electrode is B1, and an occupation ratio of the first non-connecting wires in the first electrode is C1, C1=A1/(A1+B1) is satisfied, in a case where a total area of second non-connecting wires in a second electrode of the second electrode layer is A2, a total area of second electrode wires in the second electrode is B2, and an occupation ratio of the second non-connecting wires in the second electrode is C2, C2=A2/(A2+B2) is satisfied, and at least one first electrode and at least one second electrode satisfying C2<C1 are provided.