Prism fingerprint sensor that uses a holographic optical element

Area of Science:

• Optoelectronics
• Biometrics
• Sensor Technology

Background:

• Prism-based fingerprint sensors commonly suffer from image distortion.
• Total internal reflection is a fundamental principle used in optical fingerprint sensing.
• Existing sensors often lack the resolution to capture fine fingerprint details like pores.

Purpose of the Study:

• To develop an improved prism fingerprint sensor with enhanced image fidelity.
• To mitigate distortion issues inherent in conventional prism fingerprint sensors.
• To achieve high-resolution fingerprint imaging capable of discerning ridge detail.

Main Methods:

• A right-angled prism was utilized as the core optical component.
• A holographic grating was affixed to the prism surface for finger contact.
• A light source illuminated the prism's hypotenuse, with total internal reflection principles applied.
• The grating's function was to correct optical distortions.

Main Results:

• The developed sensor demonstrated significantly reduced image distortion.
• High-quality fingerprint images were consistently acquired.
• The sensor successfully visualized minute fingerprint features, including pores on the ridges.

Conclusions:

• The integration of a holographic grating effectively corrects distortion in prism fingerprint sensors.
• This innovative design yields superior fingerprint image quality, enabling detailed analysis.
• The sensor represents a significant advancement in biometric identification technology.