Ultrasonic fingerprint sensors use high-frequency sound waves to create a detailed 3D map of your fingerprint.
Here's a breakdown of how they work:
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Sound Wave Emission: The sensor contains a piezoelectric transducer, which generates ultrasonic sound waves. These waves are directed towards the surface of your finger.
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Wave Penetration and Reflection: These sound waves penetrate the outer layer of skin (epidermis). A portion of the sound wave is absorbed, and a portion is reflected back to the sensor. The ridges and valleys of your fingerprint affect the reflection pattern differently.
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Data Acquisition: The sensor contains another transducer that acts as a receiver, capturing the reflected sound waves.
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Image Creation: The reflected waves are analyzed based on their intensity and the time it takes them to return to the sensor. This data is then used to create a detailed 3D representation of the fingerprint's unique pattern, mapping the ridges, valleys, and other surface characteristics. This 3D mapping is what makes ultrasonic sensors more secure than some other types.
In essence, ultrasonic fingerprint scanners don't just scan the surface of your finger like optical scanners; they create a three-dimensional image based on the way sound waves interact with your skin. This makes them more difficult to fool with fake fingerprints.
