With the development of high technology, fingerprint technologies are used in our life widely day by day. Today we are surrounded by good application of fingerprint recognition, such as smart phones, laptops, time and attendance, Fingerprint Access Control, fingerprint door locks.

Fingerprint Fundamental Principle:
A typical fingerprint identification system should include: Fingerprint Sensor feature extraction / matching module features Template Library application software. The fingerprint matching can be divided into two steps, the first is to be extracted fingerprint verification feature, then the fingerprint and the fingerprint template library templates similarity compared to determine whether the two fingerprint images from the same finger.
We can see that the core of the fingerprint identification accurate and efficient fingerprint analysis. Development of fingerprint identification technology is broadly divided into three collection methods: optical sensor, capacitive sensors, biological RF sensor.

1. Optical Sensor

Optical sensor recognition is the earlier fingerprint identification technology. Based on optical light emitting means, the finger incident and then reflected back into the machine to get the data, and compare the database to see if the same. Optical recognition can only reach the skin epidermis, and can not reach the dermis, but also by whether the finger clean surface greater impact. Optical sensor are used for Biometric Attendance System, employee time clock, fingerprint scanner etc.,it plays a very import role in biometric history.

2. Capacitive Sensor

Capacitive sensor identification using two capacitors mounted spaced, using fingerprint irregularities, connect or disconnect the two capacitors current finger over the fingerprint detection equipment to detect fingerprint data. Capacitive sensor requirements for a clean finger is still relatively high, and the sensor surface using a silicon material, more easily damaged. In a technical perspective, the supply of capacitive fingerprint recognition technology for Authentec, Validity, Finger Print Cards AB (FPC), etc., Authentec bought by Apple, Validity Synaptics has also been acquired. Capacitive fingerprint sensor is now the most common technique.

3. Biological RF Sensor

RF Micro sensors emit radio frequency signals through sensors, penetrating finger lines in the epidermis layer to get access to information. This approach to cleanliness finger requirements are lower. RF is a relatively new technology solutions, RF capacitance is the way, but limited to patent issues.