What is an optical fingerprint sensor?

Optical fingerprint sensor mainly uses the principle of light refraction and reflection to collect fingerprint images. Put the finger on the optical lens, under the irradiation of the built-in light source, the light is shot from the bottom to the prism, and is emitted through the prism, and the Angle of refraction of the emitted light on the uneven pattern of the fingerprint on the finger surface and the light reflected back will be different. It is projected on CCD with prism to form a digital multi-gray fingerprint image, which can be processed by fingerprint device algorithm. The ridge line (the grain line with a certain width and direction in the fingerprint image) is black, and the valley line (the concave part between the grain line) is white.

Advantages and disadvantages of optical fingerprint sensor

Optical fingerprint module has many advantages: It has experienced the test of practical application for a long time, can withstand a certain degree of temperature change, good stability, and can provide a resolution of more than 500dpi images, while the sensitivity of fingerprint recognition is very high, in addition to the fingerprint acquisition instrument generally uses tempered glass, to a certain extent can be a good protection fingerprint acquisition instrument, the service life is very long.

The disadvantage is that the volume of the optical acquisition instrument is larger than that of the semiconductor. Optical fingerprint scanner is now widely used in fingerprint door locks, fingerprint access control, fingerprint punch machine, car fingerprint anti-theft device products。