Optics-Based Fingerprint Sensor with Nano-Optical Filters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optics-based fingerprint recognition methods have security limitations due to the ease of replicating fingerprints, leading to potential unauthorized access.
Innovation Solution
An optics-based fingerprint sensor is developed, incorporating a fingerprint pixel array and spectrum pixel array with nano-optical filters, which generates fingerprint image and spectrum information to differentiate between real and fake fingerprints through liveness detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optics-based fingerprint recognition is used, then the authentication process is simple and fast, but the security level is low due to ease of fingerprint replication
Solution Approach 1:
The sensor is divided into two distinct pixel types: fingerprint pixels for capturing ridge-valley patterns and spectrum pixels for analyzing spectral characteristics. This segmentation allows each pixel type to be optimized for its specific function, enabling both traditional fingerprint recognition and liveness detection without compromising overall system performance
Solution Approach 2:
The patent adds a spectral dimension to traditional fingerprint imaging by incorporating spectrum pixels that detect light intensity across different wavelengths. This transforms the authentication process from two-dimensional spatial pattern recognition to three-dimensional analysis including spectral information, making it difficult for fake fingerprints to replicate
2Reliability
If spectrum pixels with nano-optical filters are added to detect spectral information, then liveness detection capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes natural spectral parameter differences between real and fake fingerprints across multiple wavelength bands. By detecting reflectance characteristics at different wavelengths rather than relying on precise physical filter specifications, the system achieves liveness detection through material property analysis rather than dimensional precision
Solution Approach 2:
The nano-optical filter structure is designed to replicate natural spectral absorption characteristics of human fingerprint tissue. The filter copies the spectral signature that real fingerprints exhibit, allowing the sensor to compare captured spectra against this reference pattern to identify authentications
3Adaptability or versatility
If multiple pixel types are integrated in one sensor, then comprehensive fingerprint analysis is achieved, but device complexity increases
Solution Approach 1:
Both fingerprint pixels and spectrum pixels share common structural components including the same photodiode design, color filter array, and signal processing pathways. This universal architecture allows a single sensor to perform multiple authentication functions without requiring entirely separate systems, reducing overall complexity despite enhanced capabilities
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
Enhances security by accurately distinguishing between genuine and fake fingerprints, improving the reliability of user authentication processes.
Implementation Method 1
a first photodiode, a first metal shield structure that is formed on the first photodiode and includes a first opening, a first color filter structure that is formed on the first metal shield structure and includes a second opening exposing the first opening, a second photodiode that is spaced apart from the first photodiode by a predetermined distance
Implementation Method 2
a first band limit filter structure that is formed on the nano-optical filter structure
Data Source
AI summary
An optics-based fingerprint sensor may include a first photodiode, a first metal shield structure that is formed on the first photodiode and includes a first opening, a first color filter structure that is formed on the first metal shield structure and including a second opening exposing the first opening, a second photodiode that is spaced apart from the first photodiode by a predetermined distance, a first nano-optical filter structure that is formed on the second photodiode, and a first band limit filter structure that is formed on the nano-optical filter structure.