Fingerprint Photocurrent Detection Unit Signal Conversion
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Solution Overview
Problem
Conventional fingerprint photocurrent detection methods suffer from low signal intensity and susceptibility to noise interference during fingerprint identification.
Innovation Solution
A fingerprint photocurrent detection unit that converts acquired photocurrent into a square wave signal, utilizing a conversion circuit and detection circuit to enhance signal intensity and prevent noise interference by detecting the frequency of the square wave signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fingerprint photocurrent is directly detected using conventional method, then detection process is simple, but signal intensity is low and noise interference occurs
Solution Approach 1:
The patent introduces a conversion circuit as an intermediary between the photosensitive diode and detection circuit. This conversion circuit transforms the photocurrent signal into a square wave signal, which serves as a mediator that enhances signal quality while protecting from noise interference. The intermediary conversion process resolves the contradiction by improving reliability without requiring complex detection circuits.
Solution Approach 2:
The patent replaces direct electrical signal detection with a frequency-based detection method. By converting photocurrent into square wave signals and detecting frequency characteristics instead of direct current amplitude, the system achieves better noise immunity and signal quality. This substitution of detection methodology resolves the technical contradiction between simple detection and reliable signal quality.
2Measurement precision
If conventional direct photocurrent detection is used, then device structure is simple, but measurement precision is insufficient due to low signal intensity
Solution Approach 1:
The patent changes the parameter domain of the signal from current amplitude to frequency. By converting photocurrent into square wave signals and utilizing frequency as the measurement parameter instead of direct current magnitude, the system achieves higher measurement precision. This parameter transformation resolves the contradiction between simple device structure and precise measurement.
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 increases signal intensity and reduces noise interference, improving the accuracy of fingerprint identification by converting electrical signals into frequency-based detection.
Implementation Method 1
each fingerprint sensor consists of one photosensitive diode and one switching transistor... light beams from a light source may be reflected by valleys and ridges of the fingerprint in different ways, so an intensity of the light beams received by the photosensitive diode may change, resulting in different photocurrents
Data Source
AI summary
The present disclosure provides a fingerprint photocurrent detection unit, a fingerprint identifier, a driving method and a display device. The fingerprint photocurrent detection unit includes: a conversion circuit coupled to a fingerprint photocurrent reading line and configured to convert a fingerprint photocurrent acquired by the fingerprint photocurrent reading line into a square wave signal; and a detection circuit coupled to the conversion circuit and configured to detect the square wave signal and acquire information about a fingerprint photocurrent in accordance with a frequency of the square wave signal.