Fingerprint Sensor with Movable Face and Light Guides
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Solution Overview
Problem
Fingerprint reading devices face challenges in accurately capturing images from soft or wet fingers, particularly those of newborns, infants, and young children, due to position shifts during reading, which result in low-quality fingerprint recognition.
Innovation Solution
A fingerprint reading device with a sensor drive unit that moves between capturing and recessed positions, supported by light guiding parts, to stabilize the finger and reduce elastic deformation, using near-infrared light for image capture with a CMOS image sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a finger is placed on the reading face in a particular manner, then the fingerprint reading process is initiated, but position shift occurs with respect to the sensor face resulting in low-quality images
Solution Approach 1:
The patent implements a movable sensor face that can dynamically adjust its position relative to the finger. The sensor drive unit enables the sensor face to move between a first position (for initial contact) and a second position (for stable reading), allowing the system to adapt to the finger's elastic deformation and maintain optimal reading conditions throughout the process
Solution Approach 2:
The patent employs feedback control where the system monitors the finger's placement and adjusts the sensor face position accordingly. The controller receives information about finger contact and initiates sensor movement to maintain proper alignment, ensuring high-quality fingerprint capture despite initial position shifts
2Measurement precision
If the sensor face remains stationary, then the device structure is simple, but soft fingers cause position shifts that degrade image quality
Solution Approach 1:
The patent introduces a movable sensor face with a drive unit that can adjust its position dynamically. This dynamic capability allows the sensor to track and compensate for finger movements, maintaining image quality without requiring complex external stabilization systems
Solution Approach 2:
The patent changes the positional parameter of the sensor face from fixed to variable. By enabling the sensor face to move along the vertical direction, the system can adapt to different finger conditions (soft, wet, elastic) and maintain optimal reading parameters throughout the fingerprint capture process
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 device effectively suppresses position shifts and captures high-quality fingerprint images from soft or wet fingers, ensuring accurate recognition even for sensitive subjects like newborns and young children.
Implementation Method 1
light guiding parts, using near-infrared light for image capture with a CMOS image sensor
Implementation Method 2
a light from a light source is caused to enter a finger and is scattered therein, and a light exiting from the surface of the finger is utilized to capture an image of a fingerprint
Data Source
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AI summary
Provided is a fingerprint reading device that can suppress a position shift of a finger whose fingerprint is to be read with respect to a reading face. The fingerprint reading device includes: a placement portion on which a finger is placed; a reading face with which the finger placed on the placement portion contacts; a pair of light sources that are provided on the placement portion and irradiate the finger placed on the placement portion with lights; and a reading unit that captures and reads a fingerprint of the finger in contact with the reading face in accordance with lights scattered in the finger and emitted from a surface of the finger, the pair of light sources are provided on both ends of the reading face that are opposed to each other in a width direction of the placement portion and have light guiding parts formed in a front-back direction of the placement portion, respectively, and the light guiding parts are formed so as to extend up to above the ends of the reading face.