Optical fingerprint module is the longest tested (30-year history) and the most reliable fingerprint module on the market. It has the characteristics of wear resistance, scratch resistance, good environmental adaptability, strong antistatic ability, high sensitivity and so on.
The optical fingerprint module mainly uses the principle of refraction and reflection of light.
Put the finger on the optical lens, under the illumination of the built-in light source, the light is shot from the bottom to the prism and 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 light reflected back will be different.
The prism is used to project it on the CMOS or CCD on the charge-coupled device to form a digital multi-grayscale fingerprint image in which the ridge line (the ridge line with a certain width and direction) is black and the valley line (the sunken part between the lines) is white, which can be processed by the fingerprint device algorithm.
Then the fingerprint algorithm extracts the fingerprint feature points from the acquired fingerprint image, and then converts the feature points into fingerprint feature data to store or compare with the previously stored fingerprint template data.