Working principle of capacitive fingerprint module

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

The capacitance sensor is mainly composed of a capacitance array, which contains about thousands to 10,000 miniature capacitors. When the user puts the finger on the front of the sensor, the skin forms a plate of the capacitor array, and the back of the capacitor array is the capacitor plate. Since the distances between the peaks and valleys of the fingerprints in different areas are not equal, the electric capacity of each unit changes accordingly, and thus the fingerprint image is obtained. Then the algorithm extracts feature points from the obtained fingerprint image, and then converts it into fingerprint feature data for storage or comparison with the previously stored fingerprint template data.