Ring Electrode Shielding for Fingerprint Sensing Noise
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Solution Overview
Problem
Current fingerprint identification devices and touch display devices suffer from insensitive sensing and long response times due to electrostatic interference, which reduces sensitivity and accuracy.
Innovation Solution
A sensing unit and device design featuring a substrate with thin-film transistors and sensing electrodes, where a ring electrode is placed on a first electrode layer surrounding the sensing electrodes to cancel out external electric fields and prevent electrostatic noise interference, improving sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sensing electrode structures are used, then device complexity is low, but sensing sensitivity is insufficient due to electrostatic interference
Solution Approach 1:
A ring electrode is introduced as an intermediary component surrounding the sensing electrode. This ring electrode acts as a shield that intercepts and redirects external electric fields, preventing them from directly interfering with the sensing electrode. The mediator (ring electrode) absorbs the harmful electrostatic interference while allowing the sensing function to operate with improved sensitivity.
Solution Approach 2:
The patent converts the harmful effect of external electric fields into a beneficial shielding effect. By positioning the ring electrode around the sensing electrode and applying appropriate voltages, the external electric field interference is transformed into a controlled electric field configuration that enhances the sensing performance. The harmful electrostatic noise is redirected to create a more favorable sensing environment.
2Measurement precision
If electrostatic shielding structures are added to reduce interference, then sensing accuracy improves, but response time increases due to additional capacitance
Solution Approach 1:
The ring electrode structure provides localized electrostatic shielding only in the immediate vicinity of the sensing electrode, rather than requiring comprehensive shielding throughout the entire device. This localized approach reduces the total capacitance added to the system compared to full-device shielding, thereby minimizing the impact on response time while still achieving improved sensing accuracy at the critical sensing location.
3Reliability
If multiple electrode layers are implemented to shield against noise, then anti-interference capability improves, but manufacturing complexity increases
Solution Approach 1:
The ring electrode is integrated with the existing electrode layers of the display device, merging the shielding function with the existing multi-layer electrode structure. Rather than adding completely separate shielding layers, the ring electrode is combined with the touch electrode layers, allowing the same structural elements to serve both sensing and shielding functions simultaneously, thus reducing manufacturing complexity.
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 sensing electrodes from electrostatic noise, enhancing sensitivity and accuracy, and shortening response times, thereby improving user experience and meeting market demands.
Implementation Method 1
a ring electrode disposed around the plurality of sensing electrodes... effectively shields sensing electrodes from electrostatic noise
Data Source
AI summary
A sensing unit and a sensing device are provided. The sensing unit includes a substrate; a plurality of thin-film transistors and a plurality of sensing electrodes disposed on a side of the substrate; and a ring electrode disposed on a first electrode layer. The first electrode layer is located on a side of a thin-film transistor of the plurality of thin-film transistors away from the substrate. The plurality of sensing electrodes are disposed on the first electrode layer, and the ring electrode is disposed around the plurality of sensing electrodes.