Biometric Authentication Device Using IR-VCSELs and Single Sensor
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional biometric authentication methods using visible light sources for fingerprint and vein identification are limited by noise and hardware costs due to the need for separate sensors and complex circuitry, and fail to effectively capture vein images due to the wider spectrum of IR LEDs compared to laser diodes.
Innovation Solution
A biometric authentication device employing Infra-red Vertical-cavity Surface-emitting Lasers (IR-VCSELs) as a light source, combined with a single image-sensing unit and a specific optical light guide mechanism to capture both fingerprint and vein images simultaneously, reducing hardware costs and simplifying circuit design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image-sensing unit is used to capture both fingerprint and vein images, then hardware cost is reduced and circuit design is simplified, but image quality and signal clarity deteriorate due to noise interference
Solution Approach 1:
The patent segments the imaging process into two distinct phases: fingerprint imaging using visible light and vein imaging using infrared light. The single image-sensing unit captures images at different wavelengths sequentially, separating the capture of fingerprint and vein patterns in time and wavelength domains, which reduces noise interference while maintaining hardware simplicity
Solution Approach 2:
The patent changes the wavelength parameter of illumination light to differentiate between fingerprint and vein imaging. By using visible light for fingerprints and infrared light for veins, the system optimizes image quality for each biometric feature while using a single sensor, thus resolving the contradiction between hardware simplicity and image quality
2Device complexity
If IR LED is used as light source, then hardware cost is reduced compared to laser diode, but image clarity and contrast deteriorate due to wider spectrum
Solution Approach 1:
The patent introduces an optical filter as an intermediary component between the IR LED light source and the image sensor. This filter selectively transmits specific infrared wavelengths while blocking others, effectively narrowing the spectrum of the IR LED output to achieve image clarity and contrast comparable to laser diodes, thus resolving the contradiction between cost and image quality
3Measurement precision
If visible light sources are used for fingerprint authentication, then fingerprint imaging is effective, but vein image capture is inhibited because vein images require specific non-visible wavelengths
Solution Approach 1:
The patent makes the single image-sensing unit universal by enabling it to detect both visible and infrared wavelengths. This multi-functional sensor can capture fingerprint images under visible light and vein images under infrared light, eliminating the need for separate sensors and achieving dual biometric authentication 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
The solution provides clearer and contrast-enhanced images, reducing signal processing complexity and costs, while enabling efficient biometric authentication with improved image quality and reduced noise, suitable for portable devices.
Implementation Method 1
Infra-red Vertical-cavity Surface-emitting Lasers (IR-VCSELs) as a light source
Implementation Method 2
By utilizing the VCSEL to obtain more clear images for biometric authentication
Implementation Method 3
though the vein image can be formed by the hemoglobin absorbing lights with specific wavelengths
Data Source
AI summary
A biometric authentication device uses IR-VCSELs as light sources for performing biometric authentication by providing clear images. A light guide module is introduced to minimize the size of the device. Moreover, the biometric authentication device uses a single image sensing module to gather a vein image and a fingerprint image into the same detection signal which is then analyzed and compared with the pre-stored vein feature data and fingerprint feature data.