Touch Panel Shield Electrode Noise Suppression
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Solution Overview
Problem
Existing touch panels with conductive frames suffer from noise interference due to deformation, which affects the accuracy of touch signal detection, as the capacitance between the conductive frame and wiring region changes, leading to noise in the detection signal.
Innovation Solution
A touch panel design with a conductive frame that covers the outer side of the detection region and shield electrodes placed between detection electrodes, where the distance from the detection region to the shield electrodes is shorter than to the conductive frame, ensuring constant capacitance and reduced noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conductive frame is provided around the detection region, then electromagnetic noise and static electricity are shielded, but the capacitance changes when the frame deforms causing noise in detection signals
Solution Approach 1:
A shield electrode is introduced as an intermediary component between the conductive frame and the detection region. This shield electrode acts as a mediator that blocks the harmful capacitive coupling caused by frame deformation, while allowing the conductive frame to maintain its electromagnetic shielding function. The shield electrode is electrically connected to ground potential, creating a reference potential barrier that prevents deformation-induced noise from reaching the detection electrodes.
Solution Approach 2:
The shielding function is segmented into two separate components: the conductive frame for electromagnetic noise shielding and the shield electrode for deformation noise shielding. This segmentation allows each component to perform its specific shielding function independently, with the conductive frame handling external electromagnetic interference and the shield electrode handling internal deformation-induced capacitance changes.
2Measurement precision
If the shield electrode is placed close to the detection region, then deformation noise is suppressed, but the external size increases
Solution Approach 1:
The shield electrode is positioned in the vertical dimension (thickness direction) rather than expanding the horizontal dimensions. By placing the shield electrode on the front surface of the substrate and connecting it to the conductive frame's inner surface, the noise suppression function is achieved within the existing display device footprint, utilizing the thickness dimension for shielding structure placement.
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 noise generated by conductive frame deformation, enhancing touch recognition accuracy and reducing misrecognition, while maintaining a compact display device form factor without increasing the external size.
Implementation Method 1
a shield electrode formed on the outer side of the detection region and between each of the plurality of detection electrodes, to which a shield signal that shields an electric influence for the detection region is supplied
Implementation Method 2
distance from the detection region to the shield electrode is shorter than distance from the detection region to the conductive frame
Data Source
AI summary
To shield the noise generated due to deformation or the like of the conductive frame. The touch panel includes: a detection region which generates detection signals according to a contact position of a conductor; a plurality of detection electrodes which output detection signals generated in the detection region; a conductive frame which covers above the outer side of the detection region and above the detection electrode; and shield electrodes formed on the outer side of the detection region on the CF substrate and between each of the plurality of detection electrodes, to which shield signals for shielding the electric influence on the detection region and the detection electrodes are supplied. Further, the distance between the shield electrodes and the detection region is shorter than distance between the conductive frame and the detection region.