Flexible Sensor Finger Wrapping Rolled Fingerprint Capture
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Solution Overview
Problem
Current methods for capturing rolled fingerprints require a trained operator to rotate the finger over a rigid scanner, leading to labor-intensive processes and potential artifacts due to finger movement, and do not easily capture images from the sides of the fingernail area.
Innovation Solution
A flexible sensor system with positioning members that conform to the shape of the finger, allowing for the capture of rolled-equivalent fingerprint images without rotation or rocking, using a 2D array of sensing elements and processors to ensure proper finger positioning and image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid platen fingerprint scanner is used, then the device structure is simple and stable, but it requires a trained operator to rotate the finger and may cause artifacts due to finger movement
Solution Approach 1:
Instead of moving the finger across a rigid platen, the patent inverts the approach by making the sensor flexible and moving it to conform to the finger. The flexible sensor is wrapped around the finger to capture the rolled fingerprint image, eliminating the need for operator rotation and reducing artifacts caused by finger movement.
Solution Approach 2:
The patent employs a flexible sensor that can dynamically change its shape to match the finger's curvature. The sensor transitions from a flat state to a wrapped state around the finger, allowing it to adapt to the finger's geometry and capture high-quality rolled fingerprint images without requiring manual rotation.
2Ease of operation
If a flexible sensor is used to capture rolled-equivalent fingerprints, then operator training is not required and operation is simplified, but the device complexity increases
Solution Approach 1:
The patent uses a flexible sensor constructed with flexible substrates and thin film structures that can be wrapped around the finger. This flexible construction allows the sensor to conform to the finger's shape and capture rolled-equivalent fingerprints without requiring complex mechanical rotation mechanisms or operator training.
3Adaptability or versatility
If a rigid platen scanner is used, then the device structure is simple, but it cannot capture images from the sides of the fingernail area effectively
Solution Approach 1:
The patent applies curvature to the sensor by wrapping it around the finger in a cylindrical configuration. This curved arrangement allows the sensor to capture fingerprint images from the entire finger surface, including the sides of the fingernail area, which cannot be effectively captured by a flat rigid platen.
Data Source
Figure 1~2A
Figure 2B
Figure 2C
AI summary
Biometric detection of a fingerprint is provided by a flexible sensor (3), in which one or more positioning members (31a, 31b, 52, 72) move at least a portion of the sensor (3) to conform to a shape of a finger (9) disposed along the sensor (3) to enable capture of a rolled-equivalent fingerprint for the finger. Such one or more positioning members (31a, 31b, 52, 72) move the sensor (3) causing it to curl at least along a region extending between right and left sides of a fingernail (9a) of the finger (9) around a front of the finger in order to conform the sensor (3) to the finger (9) so that the sensing elements of the sensor when enabled capture images of the rolled-equivalent fingerprints without rotation or rocking of the finger with respect to the sensor. When sensing elements are optically sensitive, one or more light sources (8a) may provide light to illuminate the finger when the sensor (3) captures rolled-equivalent fingerprint images.