Working principle of capacitive fingerprint module

Release time:2024-08-01 17:20:55

Capacitive fingerprint module is a type of fingerprint module that has only developed in recent years. It consists of a capacitive sensor and an algorithm board, and has the characteristics of simple structure, small size, and good adaptability to wet and dry fingers. It can be flexibly embedded into various volume limited products.

Capacitive sensors are mainly composed of capacitor arrays, which contain approximately thousands to 10000 miniature capacitors inside. When the user places their finger on the front of the sensor, the skin forms one of the plates of the capacitor array, and the back of the capacitor array is the capacitor plate. Due to the unequal distance between the peaks and valleys of fingerprints in different regions, the capacitance of each unit changes accordingly, thereby obtaining fingerprint images. Then the algorithm extracts feature points from the obtained fingerprint image and converts them into fingerprint feature data for storage or comparison with previously stored fingerprint template data.