Ultrasonic Fingerprint Sensor Non-Overlapping Electrodes
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Solution Overview
Problem
Current ultrasonic fingerprint sensor technologies face challenges in enhancing detection sensitivity and signal strength while maintaining design elegance and cost-effectiveness, particularly in overlapping electrode projections and reference voltage configurations.
Innovation Solution
The ultrasonic fingerprint sensor apparatus incorporates a base substrate with a first electrode layer, a piezoelectric layer, and a second electrode layer, along with reference electrode layers and an insulating barrier layer, configured to provide non-overlapping projections and optimized voltage distribution, enabling efficient ultrasonic signal generation and detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the first electrode layer and second electrode layer have overlapping projections on the base substrate, then the device can be more compact, but the detection sensitivity and signal strength are reduced
Solution Approach 1:
The patent resolves the contradiction by transitioning from a two-dimensional planar arrangement to a three-dimensional stacked configuration. The first electrode layer and second electrode layer are positioned on opposite sides of the piezoelectric layer, with their projections non-overlapping on the base substrate. This vertical stacking in the third dimension maintains compactness while ensuring spatial separation of electrode signals, thereby improving detection sensitivity and signal strength.
2Reliability
If reference electrode layers are added to provide reference voltage, then the voltage distribution is optimized, but the device complexity increases
Solution Approach 1:
The patent merges the reference voltage function into the existing electrode layer structure. The first reference electrode layer is integrated with the first electrode layer, and the second reference electrode layer is integrated with the second electrode layer, all while maintaining their respective spatial relationships. This merging approach provides stable voltage distribution without significantly increasing device complexity, as the reference electrodes are incorporated within the same structural framework rather than adding separate independent components.
3Productivity
If the first electrode layer and second electrode layer are positioned close to each other, then the ultrasonic signal generation efficiency is improved, but the risk of signal interference increases
Solution Approach 1:
The piezoelectric layer serves as an intermediary between the first electrode layer and the second electrode layer. It enables efficient ultrasonic signal generation through piezoelectric conversion while physically separating the electrode layers to prevent signal interference. The insulating barrier layer further enhances this separation by providing additional electrical isolation, allowing the electrodes to be positioned close for efficiency while preventing harmful interactions.
Solution Approach 2:
The patent extracts and emphasizes the non-overlapping projection configuration of the electrode layers. By ensuring that the projections of the first and second electrode layers do not overlap on the base substrate, the design eliminates signal interference pathways while maintaining close proximity for efficient signal generation. This extraction of the spatial separation concept is central to resolving the contradiction between efficiency and interference.
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 enhances detection sensitivity and signal strength, improves user experience, and maintains a cost-effective design by optimizing electrode projections and voltage distribution, addressing the limitations of existing technologies.
Implementation Method 1
a piezoelectric layer on a side of the first electrode layer away from the base substrate
Data Source
AI summary
An ultrasonic fingerprint sensor apparatus is provided. The ultrasonic fingerprint sensor apparatus includes a base substrate; a first electrode layer on the base substrate, and including an array of a plurality of first electrodes spaced apart from each other by an inter-electrode region; a piezoelectric layer on a side of the first electrode layer away from the base substrate; a second electrode layer on a side of the piezoelectric layer away from the base substrate, and including one or more second electrodes; and a first reference electrode layer configured to provide a first reference voltage. An orthographic projection of the first electrode layer on the base substrate is substantially non-overlapping with an orthographic projection of the second electrode layer on the base substrate. The first electrode layer and the first reference electrode layer are between the base substrate and the piezoelectric layer.