Is it better to choose optical fingerprint head or semiconductor fingerprint head for smart lock? We all know that personal fingerprints are unique and will remain unchanged for life. Therefore, using fingerprints as identification features has the advantages of stability and high efficiency, and the fingerprint scanning speed is fast, so you can read fingerprint information only by touching your finger with fingerprint collection.

　　Fingerprint reader, the carrier of fingerprint identification technology, is a high-tech security product that combines the fingerprint acquisition head and its supporting software to strengthen the encryption degree of personal computers. Fingerprint identification technology mainly involves four functions: reading fingerprint images, extracting features to save data and comparing. Fingerprint identification sensors can be divided into the following categories according to different acquisition principles:

　　First generation: optical sensor.

　　Optical sensing technology can be said to be a miniature version of the scanner. When in use, the user presses his finger on the glass surface of the scanning equipment, and the light from the light source irradiates the glass surface with fingerprints to form reflected light, which is then focused by the convex mirror and captured by the photoelectric image sensor, and compared with the database to see whether it is consistent. Due to the different concavities and convexities of fingerprints, the amount of reflected light is different. Optical scanning technology is mature, low cost and good durability, so it has become the mainstream of early fingerprint identification technology.

　　However, there are also many defects: optical recognition can only reach the skin epidermis, and it is affected by dust and grease on the finger surface, and the carefully copied finger model can also easily deceive the system; In addition, optical scanning equipment is bulky, consumes high power and takes a long time to acquire images, so it cannot be used in portable electronic products such as notebook computers and mobile phones.

　　The second generation: capacitive fingerprint sensor.

　　Thanks to the birth of silicon crystal capacitive sensor, capacitive fingerprint identification technology appeared. As shown in the figure, the capacitive sensor consists of tens of thousands of metal conductor arrays, with an insulating protective layer outside. When the finger is placed on it, the metal conductor array/insulation layer/skin forms the corresponding small capacitor array. Using the concave and convex of the fingerprint, the grain of the fingerprint can be detected by charging and discharging each pixel, and the insulating protective layer is required to be very thin. Capacitive fingerprint identification technology makes fingerprint identification really popular and enter every electronic device.

　　However, it also has some shortcomings, such as its stability is not as good as that of optical sensing technology. In addition, the silicon crystal capacitance sensor is easily affected by static electricity, which may affect the image sampling and directly damage the sensor.

　　The Third Generation: BioRF Fingerprint Identification Sensor.

　　The RF sensor is extended on the basis of the capacitive sensor. By transmitting a small amount of RF signals, it penetrates the epidermis of the finger to obtain the lines of the inner layer to obtain information. In contrast, radio frequency sensing technology can eliminate the interference of dirt and grease on the finger surface with high accuracy.

　　Electronic fingerprint lock brings more convenience to our life, so we don’t have to carry keys when we go out. Of course, many domestic customers still put safety in the first place, so an electronic lock that meets the C-level certification must be your first choice.