Ultrasonic Fingerprint Sensor, What Is The Black Technology?

- Jan 20, 2018-

Ultrasonic sensor fingerprinting technology is known as the third generation of fingerprinting technology, compared to the first and second generation fingerprinting technology, the progress is quite obvious.


The first generation of fingerprinting technology uses optical knowledge technology. Since light can not penetrate the surface of the skin (dead skin layer), it can only scan the surface of finger skin or scan dead skin layer but can not penetrate the dermis layer. In this case, the finger surface cleanliness, a direct impact on the recognition effect.


The second generation of fingerprinting uses capacitive sensor technology to form electric field by using silicon wafer and conductive subcutaneous electrolytes. The fluctuation of fingerprints will lead to different changes in the pressure difference between them, and thus accurate fingerprinting can be achieved. However, due to the sensor surface is easy to damage the use of silicon materials, resulting in reduced service life. And fingerprints formed by the concavities and convexities between the valleys and ridges of the fingerprints, so that recognition of difficult fingers such as dirty fingers or wet fingers is low.


The third generation of fingerprinting using radio frequency technology, is divided into two kinds of radio wave detection and ultrasonic detection, the principle is similar to the detection of sonar sonar material is based on specific frequency signal reflection to detect the specific shape of the fingerprint.

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Specifically, the principle is to use the ability of ultrasound to penetrate materials and produce different sizes of echoes depending on the material (the degree of absorption, penetration and reflection of the ultrasound when it reaches different material surfaces is different). Therefore, the use of skin and air for acoustic impedance differences, you can distinguish fingerprints ridge and valley where the location.


Ultrasound technology used by the ultrasonic frequency of 1 × 104Hz-1 × 109Hz, energy is controlled to the extent of non-destructive to the human body (the same intensity with the medical diagnosis).


Compared with the first and second generations, the ultrasonic fingerprint recognition technology has obvious advantages that the finger does not need to be in contact with the fingerprint module and therefore does not have much influence on the appearance of the mobile phone.


In comparison, a push-on capacitive sensor produces a two-dimensional fingerprint image, while an ultrasound scan provides more in-depth analysis and sampling of fingerprints and even penetrates the skin surface to identify unique 3D features of the fingerprint.

No capacitive sensors or pushbuttons are required to hide under a variety of material surfaces, such as glass, plastic or even metal. At the same time, the accuracy of scanning fingerprints is not affected by finger dirt, grease and sweat. If you have hands, sweat and other circumstances, still able to accurately identify, this is the Apple Touch ID can not be comparable.

Give a simple example: The first two generations of fingerprint recognition technology is concerned about the speed and accuracy of unlocking, but the user may face the trouble, such as winter finger peeling, fingerprint identification fails. The third generation of fingerprinting technology in the ultrasonic fingerprint recognition in the depth of recognition has made a breakthrough, 3D scanning technology to scan fingerprints, you can penetrate the epidermis of the finger to form a more precise and careful analysis.

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Mobile phone industry:


Take the ultrasonic scanning method, no capacitance sensor or button, you can hide in a variety of materials under the surface. Based on this technology, handset manufacturers can launch smartphones that do not require a Home button, and can also make fingerprinting more flexible, such as placing them on the screen of a mobile phone or on the bezel to further enhance the screen's share.


Not only the mobile phone, but also the future can be applied to many other fields.



Typical applications for second-generation ID card registration of personal fingerprint information, the public security organs and social units can verify the fingerprinting, can quickly and accurately "identity of the people" that can effectively prevent the fraudulent use of identity cards of others , As well as forgery and alteration of identity cards and other illegal activities, to better protect the legitimate rights and interests of citizens are not infringed. After all, compared with the first and second generation fingerprinting, ultrasonic fingerprinting can effectively prevent fingerprints of the human body from being caused by seasonal changes due to its depth and 3D technology.

Car key:


Car keyless entry system may also become another major market. Modern people can not do without the phone, the phone into a car key, the idea is becoming a reality. But for the car, safety is the number one priority, and mobile and ultrasonic fingerprinting techniques can effectively solve such problems. After all, ultrasonic fingerprint recognition in its depth of identification, as well as 3D technology can ensure safety, compared to the previous two generations of fingerprint recognition technology, the feasibility of alternative car keys higher. If you can solve the cost issues, and cooperation and cooperation with auto companies, then the era of car key will be with the arrival of ultrasonic sensor fingerprinting technology.

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