Fingerprint biometric devices incorporate capacitive touch technology which involves human fingerprint identification in its application. Like capacitive touch products, it requires the capacitance of humans', but possesses a criteria the greater recognition by fingerprints. The authentication of humans' fingerprint allows fingerprint biometric devices to be used in the security and protection of sensitive.


Fingerprint biometric devices operate by detecting a fingerprint' s capacitance, hence be able to read the live layers of skin and recognize the precise fingerprint image, notwithstanding dirt, dead skin or other obstructions. An added advantage of using capacitive technology in the recognition of fingerprint biometric product is that neither strong pressure need be applied, nor is the mere recognition of a finger' s pressure sufficient to activate the device.

The following diagram illustrates how a fingerprint biometric device works:

 

RF (or passive) capacitive. Unlike CMOS capacitance used in previous technologies, RF field sensors are built based on DC capacitive sensor principles. The finger is used as both the charge plate and the dielectric. Semiconductor-based sensors are small RF signals to detect an image of the fingerprint ridge and valley pattern, thus capturing sharp and clear fingerprint patterns from the live layer of skin just beneath the surface. A small AC signal is injected into the finger and then is measured by an array of sensors directly below the fingerprint surface. By going sub-surface, the sensor reads the live layer of skin.