Biometric Identification Device Using Dynamic Electrode Segmentation
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Solution Overview
Problem
Capacitive fingerprint recognition technologies face challenges in increasing sensing sensitivity and signal-to-noise ratio (SNR) due to high material and packaging costs, and limited product lifetime, especially when integrating sensing electrodes into IC chips or protective glass, which complicates the packaging process and reduces tolerance.
Innovation Solution
A biometric feature identification device that uses selection switches to dynamically divide electrodes into sensing and deflection electrode groups, enhancing sensitivity and SNR by applying specific stimulation and deflection signals, allowing for integration with sensing circuits on non-IC substrates and reducing chip area and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensing electrodes are integrated into IC chips or protective glass, then sensing sensitivity and integration are improved, but material cost and packaging cost increase significantly
Solution Approach 1:
The patent segments the sensing system by separating sensing electrodes from IC chips and protective glass, placing them on ordinary substrates instead. This segmentation allows independent optimization of each component and eliminates the need for expensive integrated solutions, directly reducing material and packaging costs while maintaining sensing functionality.
Solution Approach 2:
The patent employs ordinary substrates with standard packaging materials instead of expensive sapphire films or specialized protective glass. This substitution with cheaper, readily available materials significantly reduces material cost and packaging complexity while achieving the required sensing performance through electrode group configurations.
2Ease of manufacture
If sensing distance between sensing electrodes and fingerprint is increased, then packaging is facilitated, but sensing signal strength decreases
Solution Approach 1:
The patent employs dynamic signal processing techniques including multiple electrode groups that can be selectively activated and signal enhancement circuits that adaptively process sensing signals. This dynamic approach compensates for signal attenuation over increased distances, maintaining sensing precision while allowing greater electrode-to-fingerprint spacing for easier packaging.
Solution Approach 2:
The patent introduces intermediate signal enhancement circuits and multiple electrode groups as mediators between the sensing electrodes and the fingerprint. These intermediaries amplify and process the weakened sensing signals, enabling increased sensing distance without sacrificing measurement precision.
3Reliability
If sensing electrodes are disposed under protective glass, then device tolerance is improved, but chip area increases and cost rises
Solution Approach 1:
The patent segments the sensing system by placing sensing electrodes on ordinary substrates rather than integrating them into protective glass or large IC chips. This segmentation reduces the area requirement on expensive substrates while maintaining device tolerance through separate protective structures and signal processing approaches.
Solution Approach 2:
The patent moves the sensing electrodes from a two-dimensional plane on expensive substrates to a three-dimensional configuration involving multiple layers and depths. By utilizing vertical stacking and multiple electrode groups at different positions, the system achieves enhanced tolerance and sensing capability without increasing the planar chip area.
4Productivity
If full area detection is implemented, then recognition efficiency is improved, but ambient noises and signal complexity increase
Solution Approach 1:
The patent divides the sensing area into multiple electrode groups that can be selectively activated. This segmentation allows focused sensing on relevant regions rather than processing signals from the entire sensing area simultaneously, reducing ambient noise interference and signal complexity while maintaining recognition efficiency through coordinated group activation.
Solution Approach 2:
The patent employs partial action by selectively activating specific electrode groups based on sensing needs rather than continuously monitoring all electrodes. This approach reduces the processing of irrelevant signals and ambient noises while maintaining full detection capability when required, optimizing the balance between recognition efficiency and signal 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
This approach increases the stability and correctness of fingerprint recognition, reduces device costs, and extends product lifetime by improving sensing sensitivity and SNR, while simplifying packaging and allowing for integration with non-IC substrates.
Implementation Method 1
capacitive fingerprint identification
Implementation Method 2
applying specific stimulation and deflection signals
Data Source
AI summary
A biometric feature identification device includes a substrate, an electrode layer, and a switch and trace layer. The electrode layer is arranged at one side of the substrate and has a plurality of electrodes. The switch and trace layer has a plurality of switches and a plurality of traces. The switches are provided to divide the plurality of electrodes sequentially or dynamically into at least one sensing electrode group and a plurality of deflection electrode groups corresponding thereto. Each sensing electrode group corresponds to at least two deflection electrode groups. Each sensing electrode group has at least one electrode for sensing. Each deflection electrode group has a plurality of electrodes for deflection.