Capacitance Touch Electrodes Shielding External Noise
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Solution Overview
Problem
Capacitance type touch panels are prone to malfunction due to external noise from sources like inverter fluorescent lamps and AM radio waves, which can cause improper detection, and existing solutions do not effectively make the electrodes inconspicuous.
Innovation Solution
A display device with a capacitance type touch detection system that includes plural first electrodes, a shield electrode, an insulating layer, and a semiconductive layer, where the shield electrode surrounds the first electrodes and the semiconductive layer is positioned opposite to both, with a potential difference of 0.5V or less between the first electrodes and the shield electrode, or where the shield electrode's potential is higher than the first electrodes, to reduce noise interference and make the electrodes less visible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shield electrode is added around the touch detection electrodes to reduce external noise interference, then the reliability of the touch panel is improved, but the device complexity increases
Solution Approach 1:
The patent combines the shield electrode function with existing electrode structures in the touch panel. The shield electrode is integrated into the electrode arrangement rather than being completely separate, merging multiple functions into a unified structure that reduces noise while maintaining simplicity.
Solution Approach 2:
The shield electrode acts as an intermediary element between the external environment and the touch detection electrodes. It mediates the electromagnetic field interactions by providing a protective barrier that blocks external noise from reaching the sensitive detection electrodes, thereby improving reliability without requiring fundamental changes to the touch panel architecture.
2Measurement precision
If the electrodes are made more visible to improve detection accuracy, then the measurement precision is improved, but the aesthetics deteriorate
Solution Approach 1:
The patent applies different properties to different parts of the electrode system. The touch detection electrodes maintain their functional characteristics for accurate detection, while the shield electrode is designed with properties that make it less visually prominent. This local differentiation allows the detection electrodes to be sufficiently visible for function while the overall appearance remains aesthetic.
Solution Approach 2:
The patent utilizes color and transparency variations in the electrode materials and surrounding layers. By adjusting the optical properties such as transparency, color matching, and reflective characteristics of the electrode layers and insulating materials, the electrodes can maintain detection precision while appearing less conspicuous to the human eye, thus preserving aesthetics.
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
The solution effectively shields the first electrodes from external noise, reducing the risk of malfunction and making the electrodes inconspicuous, thereby enhancing the reliability and aesthetics of the touch panel.
Implementation Method 1
the shield electrode is formed apart from the plural first electrodes so as to surround the whole plural first electrodes along an arrangement surface
Implementation Method 2
detects a touch by using variation of capacitance formed in these intersections due to external near-field objects
Data Source
AI summary
A display device is provided and includes a first substrate; a second substrate opposed to the first substrate; a liquid crystal layer between the first substrate and the second substrate; a plurality of detection electrodes, the second substrate being located between the detection electrodes and the liquid crystal layer; a shield electrode apart from the detection electrodes in a plane view, the second substrate being located between the shield electrode and the liquid crystal layer; and a resistive layer overlapping the detection electrodes and the shield electrode, the detection electrodes and the shield electrode located between the resistive layer and the second substrate.