Capacitive Fingerprint Module Working Principle

In today's digital age, fingerprint recognition technology has made its way into our daily lives, everywhere from unlocking smart door locks to verifying security access control systems. As an efficient and secure biometric technology, capacitive fingerprint modules have become a core component of many smart devices due to their superior accuracy and anti-counterfeiting capabilities. So, how does capacitive fingerprint module actually work? What are the advantages of its application in various smart products? Today, we'll take a closer look at the basic principles, workflow, and wide range of applications of capacitive fingerprint modules in different industries.

In this field, IDWorld has won unanimous praise in the industry with its more than 20 years of accumulation in fingerprint technology, especially in its self-developed fingerprint algorithm. Whether it is a standard capacitive fingerprint module or a customised solution we can provide a full range of products to meet various needs and are trusted by our customers.

Workflow of Capacitive Fingerprint Module

Touch sensing process of capacitive fingerprint module

When the user puts his/her finger on the capacitive fingerprint module, the module will start working immediately. This process can be divided into the following steps:

The sensor receives the capacitance change of the fingerprint: after the finger touches the surface of the capacitive fingerprint module, the sensor will detect the capacitance change between the fingertip and the sensor surface. The raised and depressed parts of the fingerprint will result in different capacitance values, and these capacitance changes help the sensor to recognise the shape of the fingerprint.

Reading and conversion of capacitance values: the sensor converts the captured capacitance data into electrical signals and transmits them to the microprocessor. The microprocessor receives these signals and further converts them into a digital image. Every detail of the fingerprint is converted into an analysable digital signal for subsequent processing and verification.

Pre-processing and Image Generation: The capacitive data collected by the sensor is processed into a fingerprint image that contains all the detailed features of the fingerprint such as ridges, bifurcation points, end points etc. The clarity and accuracy of the image directly affects the subsequent matching process, so pre-processing (denoising, enhancement) is a crucial step.

Data Matching and Verification of Capacitive Fingerprint Module

When the capacitive fingerprint module completes the fingerprint image acquisition, the next step is to enter the data matching stage. This process involves comparison and verification to confirm the identity of the fingerprint. The specific process is as follows:

Fingerprint data matching in the database: when the user enters the fingerprint for the first time, the characteristic data of the fingerprint will be saved in the database. Subsequently, when the user is verified again, the capacitive fingerprint module will compare the captured fingerprint image with the fingerprint features in the database. This comparison is done by a matching algorithm, which usually looks for common features in the fingerprints to judge whether they match or not.

Match judgement and verification result: The capacitive fingerprint module will calculate the match between the two, usually the higher the match, the stronger the verification accuracy. If the match is high enough, the verification is successful and the user's identity is confirmed; if the match is low, the verification fails and the user may be asked to re-enter the fingerprint. Common matching algorithms include feature point-based matching and template-based matching.

Processing and feedback of output results

After the verification process, the capacitive fingerprint module will make corresponding feedback based on the matching results. The main processes are as follows:

Feedback mechanism after successful verification: when the user's fingerprint passes the verification, the capacitive fingerprint module will give feedback on the successful verification by visual or auditory means. For example, common feedback methods include displaying a green light, popping up the welcome interface or emitting a beep. These feedbacks can effectively notify the user of the verification result and enhance the user experience.

Re-entry or warning after verification failure: If verification fails, the capacitive fingerprint module will prompt the user to re-enter the fingerprint. Common feedback methods include displaying a red light, popping up an error alert box, or emitting a warning tone. The system may also ask the user to check if the finger is placed correctly or if there are any smudges affecting the recognition.

Application Scenarios and Advantages of Capacitive Fingerprint Modules

Application of Capacitive Fingerprint Module in Smartphone

The application of capacitive fingerprint module in smartphones has become very popular, especially in the security and user experience of smartphones, which plays a key role.

User authentication: Capacitive fingerprint modules can effectively perform authentication by accurately recognising the user's fingerprint. Compared with the traditional password authentication method, fingerprint authentication is more secure and faster. Users do not need to memorise complex passwords, but only need to touch the fingerprint module to complete the authentication.

Enhanced security: Capacitive fingerprint module is highly resistant to anti-counterfeiting, and fingerprints are highly unique and difficult to copy, making the security of mobile phones greatly enhanced. In addition, capacitive sensors capture fingerprints through capacitance changes and cannot be forged through simple pictures or moulds, which increases the security of fingerprint identification.

Application of Capacitive Fingerprint Module in Access Control System

Capacitive fingerprint modules are increasingly being used in access control systems, especially for their significant advantages in improving security and convenience.

Enterprise and home security solutions: Capacitive fingerprint module is widely used in enterprise's access control system, through the fingerprint verification to enter a specific area, avoiding the security risks of traditional keys and passwords. Meanwhile, in the home, capacitive fingerprint module can effectively protect home security and prevent illegal invasion.

Efficient and convenient way of identity verification: Compared with the traditional way of swiping cards or entering passwords, capacitive fingerprint module is faster and more convenient, and the contactless design avoids the risk of wear and tear or leakage caused by frequent contact, and improves the safety and comfort of use.

Technical Advantages of Capacitive Fingerprint Module

Capacitive fingerprint module has many unique technical advantages compared with other fingerprint identification technologies.

High-precision identification and anti-counterfeiting: The high precision of capacitive fingerprint modules enables them to capture minute differences in fingerprints, and can effectively identify subtle changes in the pattern, providing higher identification accuracy. In addition, capacitive sensors cannot be duplicated by simple moulds or images, thus enhancing anti-counterfeiting.

Low Power Consumption: Capacitive fingerprint module is suitable for various electronic products, such as smart phones and access control systems, due to its low power consumption characteristics, which ensures long-term stable working condition.

Overall, capacitive fingerprint module is becoming the technology of choice in all kinds of smart devices with its advantages of high precision, low power consumption and easy integration. Whether it is smartphones, access control systems, or financial payment devices, it is providing a safer and more convenient user experience. In this field, IDWorld, with its leading technology and rich experience, has been committed to providing the highest quality fingerprint identification solutions to customers around the world. With its self-developed fingerprint algorithms and a full range of products, IDWorld plays an indispensable role in the development of fingerprint identification technology and will continue to lead the industry towards a smarter and more secure era in the future.