How does the Fingerprint sensor work?

Fingerprint sensor module technology principle introduction. Fingerprint, because of its lifelong invariance, uniqueness and convenience, has almost become a synonym for biometric identification. Fingerprints refer to the ridges and ridges on the front skin of a person's fingers. The lines are arranged regularly to form different patterns. This is the basis of fingerprint recognition.

Fingerprint modules can be divided into fingerprint recognition methods.

Optical fingerprint sensor module: identifies fingerprints based on the principle of light refraction and reflection.

Capacitive fingerprint sensor module: Collects fingerprints by changing the value of the capacitor.

Ultrasonic fingerprint sensor: detects patterns using tiny radio-frequency signals.

Optical fingerprint sensor module: Based on the principle of light refraction and reflection, the light shines from the bottom to the prism and is emitted through the prism. The Angle of refraction of the emitted light on the uneven lines of the fingerprint on the finger surface and the brightness and darkness of the reflected light will be different. CMOS or CCD optical devices will collect different degrees of light and dark picture information to complete the fingerprint collection.

Capacitive fingerprint sensor module: Whether capacitive or inductive, the principle is similar, in a "plate" integrated with thousands of semiconductor devices, the finger is attached to it and it forms the other side of the capacitor (inductance), because the finger plane is uneven, the actual distance between the convex point and the concave point contact the plate is not the same, and the capacitance/inductance value is not the same. The device summarizes the different values collected according to this principle, and completes the collection of fingerprints.

Ultrasonic fingerprint sensor: Using biofrequency fingerprint recognition technology, the sensor itself emits a trace RF signal, penetrates the epidermal layer of the finger to control and measure the inner layer pattern, so as to obtain the best fingerprint image. The anti-counterfeiting fingerprint ability is strong, and the principle of radio frequency identification only reacts to the dermal skin of people, fundamentally eliminating the problem of artificial fingerprints.

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