Fingerprint Identification Device Shielding Enhancement
Solution Overview
Problem
Capacitive fingerprint identification devices face challenges with high material and packaging costs, reduced yield, waterproofing, and safety concerns due to complex structures and high noise levels, particularly in press-type fingerprint identification systems.
Innovation Solution
A fingerprint identification device with a fingerprint detection circuit not requiring high voltage integrated circuit processing, utilizing a plurality of sensing electrodes, shielding enhancement electrodes, and an auxiliary enhancement signal circuit to enhance signal quality and reduce manufacturing costs, where the auxiliary enhancement signal circuit is powered separately and generates a larger amplitude signal to improve fingerprint detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sensing electrodes and sensing circuit are packaged in one integrated circuit chip for press-type fingerprint identification, then identification capability and efficiency are improved, but material cost and packaging process cost greatly increase
Solution Approach 1:
The patent divides the fingerprint identification system into separate components: sensing electrodes, shielding electrodes, and a simplified detection circuit. This segmentation allows the sensing circuit to be implemented without complex high-voltage integrated circuit processes, reducing manufacturing costs while maintaining identification efficiency through coordinated operation of the separated components.
Solution Approach 2:
The patent introduces shielding enhancement electrodes as intermediary elements between the sensing electrodes and the external environment. These shielding electrodes, controlled by the auxiliary enhancement signal circuit, mediate the electromagnetic environment to improve signal quality without requiring complex integration of the sensing circuit, thus reducing manufacturing complexity and cost.
2Productivity
If sensing electrodes and sensing circuit are packaged in one integrated circuit chip, then identification capability is improved, but yield and waterproof performance are reduced
Solution Approach 1:
By segmenting the system into separate sensing electrodes, shielding electrodes, and a simplified detection circuit, the patent avoids the need for complex sealed integrated circuit packaging. This segmentation inherently improves yield and waterproof performance while maintaining identification capability through the coordinated operation of the separate components.
Solution Approach 2:
The patent extracts the high-voltage signal generation function to a separate auxiliary enhancement signal circuit, leaving the fingerprint detection circuit to use only low-voltage processes. This extraction eliminates the need for complex high-voltage integrated circuit packaging, thereby improving yield and waterproof performance while preserving identification capability.
3Measurement precision
If high voltage integrated circuit process is used for fingerprint detection circuit, then signal noise ratio is improved, but circuit area and manufacturing cost increase
Solution Approach 1:
The patent extracts the high-voltage signal generation function to a separate auxiliary enhancement signal circuit, allowing the fingerprint detection circuit to be implemented with low-voltage processes only. This extraction maintains signal noise ratio performance while dramatically reducing the circuit area and manufacturing cost associated with high-voltage integrated circuit processes.
Solution Approach 2:
The auxiliary enhancement signal circuit acts as an intermediary that provides high-voltage signals to the shielding electrodes, enabling improved signal noise ratio without requiring the main fingerprint detection circuit to use high-voltage processes. This intermediary approach reduces the circuit area and manufacturing cost of the detection circuit itself.
4Ease of operation
If complex button structure with metal frame is used to hold fingerprint identification IC, then identification operation is enabled, but device complexity and safety risks increase
Solution Approach 1:
The patent extracts the high-voltage signal generation function to a separate auxiliary enhancement signal circuit, eliminating the need for complex high-voltage integrated circuit packaging and metal frames. This extraction simplifies the overall device structure while maintaining fingerprint identification operation through the coordinated use of sensing and shielding electrodes.
Solution Approach 2:
The patent implements a simplified detection circuit that can operate with either integrated or separate electrode configurations. This multi-functional approach allows the system to achieve fingerprint identification operation without requiring complex button structures with metal frames, thereby reducing device complexity and safety risks.
5Measurement precision
If high voltage integrated circuit process is used, then fingerprint sensitivity and signal noise ratio are improved, but manufacturing cost and circuit area increase
Solution Approach 1:
The patent extracts the high-voltage signal generation function to a separate auxiliary enhancement signal circuit, allowing the fingerprint detection circuit to use cost-effective low-voltage processes. This extraction maintains fingerprint sensitivity and signal noise ratio through the combined operation of the detection circuit and shielding electrodes, while dramatically reducing manufacturing cost and circuit area.
Solution Approach 2:
The auxiliary enhancement signal circuit serves as an intermediary that provides high-voltage signals to improve fingerprint sensitivity and signal noise ratio without requiring the main detection circuit to use expensive high-voltage integrated circuit processes. This intermediary approach reduces manufacturing cost and circuit area while maintaining measurement precision.
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 significantly increases fingerprint image accuracy, reduces manufacturing costs, and enhances safety by eliminating the need for high voltage processing in the fingerprint detection circuit, while maintaining independence between power sources to prevent current loops and improve signal-to-noise ratio.
Implementation Method 1
The fingerprint detection circuit transmits a capacitive stimulation signal of the capacitive stimulation signal source to a selected fingerprint sensing electrode
Implementation Method 2
at least one shielding enhancement electrode corresponding to a plurality of the fingerprint sensing electrodes
Implementation Method 3
applies the fingerprint sensing signal and the capacitive stimulation signal signals individually or together to an amplifier with a gain greater than or equal to zero
Data Source
AI summary
A fingerprint identification device includes a plurality of fingerprint sensing electrodes, a shielding enhancement electrode, a fingerprint detection circuit and an auxiliary enhancement signal circuit. The shield enhancement electrode corresponds to a plurality of the fingerprint sensing electrodes. The fingerprint detection circuit is powered by a first power supply and includes a capacitive stimulation signal source. The auxiliary enhancement signal circuit is powered by a second power supply and includes an auxiliary enhancement signal source. The fingerprint detection circuit transmits a capacitive stimulation signal to a selected fingerprint sensing electrode, and receives a fingerprint sensing signal. The fingerprint sensing signal is amplified to generate a capacitive elimination shielding signal. The capacitive elimination shielding signal is transmitted to the shielding enhancement electrode. The auxiliary enhancement signal circuit outputs an auxiliary enhancement signal to the shielding enhancement electrode for performing a fingerprint detection operation.