The uniqueness of human fingerprints and the complexity of the fingerprint recognition principle in fingerprint locks contribute to their higher level of security. This is why fingerprint locks are widely used in high-security fields such as door locks, smartphone unlocking, and mobile payments. So, how does the fingerprint recognition principle of fingerprint locks actually work?

In the fingerprint lock field, the core is the fingerprint sensor and recognition technology. Currently, fingerprint sensors on the market mainly include optical fingerprint sensors and semiconductor fingerprint sensors, representing capacitive and optical fingerprint recognition technologies, respectively. These two fingerprint recognition technologies share similar principles but differ significantly in the method of collecting fingerprints.

Firstly, capacitive fingerprint recognition is more complex than optical, integrating pressure, capacitive, and thermal sensors onto a single chip. When the fingerprint presses the chip surface, the internal capacitive sensor forms a fingerprint image based on the charge difference (or temperature difference) generated by the fingerprint's peaks and valleys. This image is then matched with the fingerprint database inside the phone to complete the fingerprint recognition process.

Due to its complexity and higher costs, capacitive fingerprint recognition technology offers advantages such as faster recognition speed, higher accuracy, the ability to identify live fingerprints, and prevent fake fingerprints from bypassing security measures. Consequently, it is adopted by high-end fingerprint lock brands and the smartphone industry, where capacitive refers to the fingerprint sensor.

For optical fingerprint recognition, what most people are familiar with is the fingerprint attendance machines at work. However, optical fingerprint recognition technology is also used in access control systems, fingerprint locks, and identity verification machines for exams.

This optical fingerprint recognition primarily encompasses four key functionalities:

The fingerprint module is responsible for capturing fingerprint images.

2. The digital signal processor primarily converts the collected fingerprint images into digital signals.

3. The microcontroller serves as the control unit for the entire system, where fingerprint verification and command output will take place.

4. The LCD display will output the fingerprint verification results.