Evolutionary history of fingerprint recognition: How will smart lock recognition technology develop?

Optical fingerprinting is not reliable

When I was a kid, I watched movies and felt that the fingerprint recognition in science fiction movies was very cool. Unexpectedly, almost overnight, fingerprint recognition came to our lives. Since there are fingerprint recognition modules on smart phones, mobile payment is very popular in China. Mobile payment is even listed as “new four inventions” by foreigners along with “high-speed rail”, “shared bicycle” and “online shopping”.

In the field of Internet of Things, smart locks are the most popular devices for fingerprint recognition. There are also many companies that use fingerprints for attendance. Although you use your fingerprint to unlock your phone every day, or make a payment, do you really know fingerprint recognition? How can it be unlocked with your fingerprint, and how to protect your mobile phone content and payment Safe?

The optical fingerprint acquisition device began in 1971 and works like a camera. Since the finger will leave a fingerprint on the glass, the sensor is made of a glass surface layer. Under the surface of the glass, there is a fluorescent light-emitting layer. The light-emitting layer illuminates the fingerprint pattern formed by the contact between the finger and the glass. At this time, the image sensor under the glass is Scanning is performed, and the scanned fingerprint pattern is compared with the fingerprint image in the memory to complete an authentication.

The disadvantages of optical fingerprint sensors are obvious. The first is due to the use of optical scanning, the quality of which depends entirely on the skin condition of the finger scanning surface. If the fingerprint is covered with dead skin or excessive dust. Or there is damage and staining, which will directly affect the results of the scan. Moreover, since the optical fingerprint sensor only scans the two-dimensional image of the finger and the glass, and does not detect the material of the fingerprint, the fingerprint sensor can be easily fooled by using a fingerprint film or the like.

Capacitive fingerprint recognition has greater advantages

In addition, due to structural problems, this fingerprint recognition module can not reduce the volume to a very small size, and the security is not very safe. Therefore, the optical fingerprint identification module only appears to be not particularly high in security requirements. Fingerprint attendance machine, fingerprint collector. However, the pursuit of fingerprint security is not limited to this. The development of capacitive fingerprint sensors has shaken the status of optical fingerprint sensors.

Many people remember that the fingerprint on the notebook needed to slide on it. This is the shape of the early capacitive fingerprint sensor. At that time, the fingerprint sensors on many laptops were linear, that is to say, different from the optical fingerprint sensor. Two-dimensional CCD/CMOS image sensor, the pixels of this sensor are often only one-dimensional array arranged in a row, so the finger needs to be swiped from the sensor, so that the fingerprint recognizer can sequentially read images of different parts of the finger, and finally splicing Complete fingerprint recognition.

Although this type of capacitive fingerprint sensor has a reduced volume, in fact, due to the need for sliding scanning, there is still a high requirement for the direction and movement of the finger. When sliding, there must be no pause at a constant speed, and it is necessary to slide in the same direction. Turning, this makes the user experience drop.

However, due to the small size of the capacitive fingerprint sensor, the application of the fingerprint sensor is more extensive than the optical fingerprint sensor mentioned above. In laptops, electronic door locks (there are no smart attributes at the time) appear, even when the push-type fingerprint recognition technology on the mobile phone is not mature enough, fingerprint recognition is also used to unlock. After the release of the iPhone 5s, push-type fingerprinting began to become the target of all fingerprint identification R & D companies.

At this time, there are two vendors that have to mention, one is AuthenTec, and the other is called FingerPrintCardsAB (hereinafter referred to as FPC). These two manufacturers have an indelible contribution to the development of push-type fingerprinting.

AuthenTec is an Israeli company founded in 1998. It is the world's leading provider of fingerprint authentication sensors and solutions for mass PCs, wireless devices and access control markets. With a monthly shipment of 100 million fingerprint scanners, it has nearly 200 patents covering fingerprint identification chips, packaging, software and Final use and other aspects. But how can this leader in fingerprint recognition be seen by Apple and acquired?

This company makes Apple’s eyes

In 2011, AuthenTec developed a new fingerprint recognition technology based on capacitance and radio frequency identification, called “TruePrint”. The patented TruePrint technology can read the active layer under the skin surface (where the human fingerprint is actually located). Extremely accurate and reliable fingerprint imaging. This subcutaneous reading method can cope with common skin surface conditions and truly read all fingerprints anytime, anywhere.

The basic principle is to form a finger with one pole of the capacitor, and the fingerprint sensor is another pole. When the sensor needs to be recognized, the sensor applies a voltage to the surface of the finger. Because the unevenness of the finger is uneven, the electric field value measured by each sensor is also different, so that a fingerprint image can be drawn by a sufficiently dense sensor pixel. Moreover, since the dead skin is not electrically conductive, the fingerprint image of the dermis layer can be directly detected.

From the end of 2011 to the beginning of 2012, AuthenTec began to make contact with consumer electronics manufacturers, including HP, Lenovo, Fuji, Samsung, Lucent and other major customers, hoping to get funding from other vendors. But few manufacturers are interested in this matter. In the end, only Apple had a high level of attention to this matter, so AuthenTec executives began negotiating with Apple, but they were still in a stalemate.

In March and April of 2012, Apple proposed to acquire the company's engineering team to develop products for Apple, but AuthenTec executives did not agree. The two sides then conducted several negotiations. The final result was seen by everyone: on July 27, 2012, Apple acquired AuthenTec for $356 million. And after that, the world's first push-type fingerprint recognition phone that shocked the industry was launched.

The reason why so many manufacturers are not interested in this kind of fingerprint recognition is that there is no durable material that can protect the sensor pixels on the surface of the fingerprint sensor, and the cost of research and development is high.

Since the electric field generated by the detection is very weak and the finger and the sensor need to be as close as possible, a protective layer that allows the sensor to penetrate the protective plate without excessive noise is required to ensure the accuracy of the recognition.

Fingerprint recognition makes most smart lock manufacturers headache

On the other hand, the strength of the protective layer is also high enough and durable enough. Because the protective plate is to be exposed, the contact materials include but are not limited to fingers, there are grease, water stains, sand dust, etc., but also to withstand the test of temperature and humidity, the development of this protective layer needs to invest a lot Research and development costs.

Until Apple acquired AuthenTec and released the iPhone5s with push-type fingerprint recognition, Apple's solution to develop this protective layer was released to the public: sapphire glass (SAPPHIRECRYSTAL). However, the sapphire glass used by Apple is not a gemstone, but a synthetic material. The main component is aluminum oxide, which has the same chemical composition and physical properties as natural sapphire. Sapphire glass has good thermal properties, excellent electrical and dielectric properties, and is resistant to chemical corrosion. It is resistant to high temperatures, good thermal conductivity, high hardness, transparent infrared, and good chemical stability. The surface of many expensive watches is covered by this substance.

Since push-type fingerprinting has been solved first after Apple acquired AuthenTec, Android phone manufacturers can only look at it. They are also very anxious, because the use of push-type fingerprint recognition almost kills the scheme of scratch-type fingerprint recognition, and other manufacturers with fingerprint identification schemes have no similar solution, Samsung is even more eager to choose on its flagship machine. Scratch fingerprint recognition.

However, on the electronic lock, due to the frequency of use, the experience of the scratch-type capacitive fingerprint recognition and the press-type experience are not much different, so the electronic lock is still used in the scratch-type capacitive fingerprint identification scheme, For the sake of cost considerations, the optical fingerprinting scheme mentioned at the outset was adopted.

At that time, mobile phone manufacturers were far more expensive than electronic lock manufacturers, so they could only follow the direction of mobile phone manufacturers in the choice. At this time, a Swedish manufacturer brought a new direction to mobile phone manufacturers and electronic lock manufacturers. At this time, the electronic lock has a smart attribute and became a smart lock. This manufacturer is an FPC.

Smart lock manufacturers find life-saving straw

In September 2014, Huawei released the Mate7 mobile phone, which uses contact fingerprint recognition on the back, and the use experience is close to the push type, which is much better than the scratch type. Using FPC's "FPC1020" fingerprint identification solution, it became the first Android mobile phone with a push-type fingerprint recognition solution. Its solution provider FPC also became famous because of the phone's reputation.

Huawei mate7 uses FPC fingerprint unlocking solution

Founded in 1997, FPC is a Swedish manufacturer and a leading biometric technology company. Dedicated to the development, production and sale of biometric components and technologies to help identify users by analyzing and comparing their unique fingerprints.

Because the "big boss" AuthenTec in the fingerprint recognition industry has been acquired by Apple, and the technology is not authorized. The former FPC received a high degree of attention after the breakthrough in technology, and it is almost the only choice for the push-type capacitive fingerprint identification scheme. In 2014, the Internet of Things (IoT) concept was a big fire, and the electronic locks also caught up with the IoT, which was set up for smart locks. Fingerprint recognition is the optimal solution for unlocking smart locks. It is more convenient and safer than traditional password unlocking.

Due to the breakthrough of fingerprint recognition technology and the popularity of fingerprint recognition on smart phones, the cost of purchasing fingerprint identification modules is getting lower and lower. Therefore, smart locks using fingerprint recognition modules on smart locks are more and more, and the price is reasonable. After several program updates, domestic smart home and smart lock manufacturers have adopted FPC's fingerprint identification scheme and used it as one of the selling points.

Of course, the glory of FPC is not just a big hit. Its technical strength is still very strong. For example, the FPC fingerprint identification module has a very important feature: biometric detection and recognition. To put it simply, the fingerprint recognition module can detect whether the fingerprint is a human hand or a fake fingerprint film. This technology is very important in terms of security.

How will future biometrics develop?

Although fingerprints have great advantages in terms of the complexity of the key, since human skin has been secreting metabolites such as oil and fat, fingerprints are relatively easy to obtain, on mobile phones, on mirrors, on teacups, etc. You can find the fingerprint. Nowadays, after acquiring the fingerprint, the cost of copying the fingerprint film is not high, and the criminals are still able to take advantage of it. However, FPC's in vivo detection and recognition technology can identify other fingerprints such as fingerprints and refuse to pass. This makes the security of smart locks much better.

Not only that, FPC's fingerprint identification module can also be waterproof, dustproof and anti-static. This allows smart locks with fingerprints to be placed in an outdoor environment without being easily damaged. After all, smart locks are the most important barrier for a nursing home. If safety is not good enough, it can't be compared with traditional mechanical locks several times higher.

Just when many mobile phone manufacturers are working on fingerprint recognition and full screens, Apple, the leader of fingerprint identification, has thrown out a “king of the king”: iPhoneX cancels fingerprint recognition and uses facial recognition technology. This Wang Bian once again made many smartphone manufacturers suddenly unable to find their way.

But facial recognition is a great opportunity for smart locks. From the scene, if the smart lock can achieve facial recognition, then standing in front of the door without even stretching can open the door, which is more convenient than fingerprint unlocking. From the perspective of security, the three-dimensional features of the face are more difficult to obtain and copy than the fingerprints, thus ensuring the safety of the user.

Since Apple technology is not publicly available, it can only wait for other manufacturers to follow up on this technology. If the popularity of the fingerprint recognition era can be repeated, the smart lock will become more convenient and intelligent. Perhaps there will be a sudden development of recognition technology that is more suitable for smart locks than facial recognition.

Editor in charge: Malan