As the earliest application of biometric technology and the most successful fingerprint identification technology, it has played a huge business opportunity through continuous promotion and use around the world.
There are four main types of fingerprint image acquisition technologies:
- optical scanning devices
- capacitive fingerprint sensors
- temperature-sensitive fingerprint sensors
- ultrasonic fingerprint scanning
Optical fingerprint scanner introduction
Optical fingerprint scanning technology is based on optical technology acquisition technology, this technology is also relatively rescue in history, and it is also a relatively widely used technology. Put your finger on the optical mirror, the finger is illuminated by the built-in light source, and the prism is used to project it to the
On the charge-coupled device (on the CCD), the ridge line (the ridge line with a certain width and direction in the fingerprint image) is formed in black, and the valley line (the concave part between the ridge lines) is digitized in white, which can be used by the fingerprint device algorithm. Processed multi-grayscale fingerprint images
Optical fingerprint capture technology has obvious advantages:
- It has been tested for a long time
- Use temperature difference to some extent
- High resolution up to 500DPI, etc.
- low price
There are also some disadvantages:
- Requires a sufficiently long optical path
- Need to be large enough
- Overly dry and overly oily fingers will also vary the effect of optical fingerprint products
There is a prism in the sensor, and its volume is large, generally several times or even 10 times the size of a semiconductor, so its application in small devices is limited. There is no volume limit when used on large devices such as attendance machines and access control, but when used on USB flash drives, mobile hard drives, and handheld devices, volume has become the biggest obstacle. Low cost has always been considered the biggest advantage of optical sensors, but due to the difficulty in ensuring the consistency of its manufacturing process, with the large-scale development of semiconductor sensors represented by capacitive sensors, the cost advantage of optical sensors is no longer obvious. While most companies are still using optical sensors, the trend is toward novel, high-quality semiconductor capacitive fingerprint sensors.
Temperature difference induction recognition technology
The temperature difference sensing recognition technology is based on the principle of temperature sensing. Each pixel is equivalent to a miniaturized charge sensor, which is used to sense the temperature difference at a certain point between the finger and the image area of the chip, and generate a representative image information. electrical signal.
Its advantage is that the fingerprint image can be acquired within 0.1s, and the sensor volume and area are the smallest. The disadvantage is: subject to temperature limitations, over time, the finger and the chip will be at the same temperature.
Semiconductor silicon sensing technology (capacitive technology)
In the late 1990s, technologies based on the semiconductor silicon capacitance effect tended to mature. The silicon sensor becomes one plate of the capacitor, and the finger is the other plate. The 8-bit grayscale image is formed by using the capacitance difference between the ridges and valleys of the fingerprint line of the finger relative to the smooth silicon sensor.
The capacitive sensor emits an electronic signal, which will pass through the surface of the finger and the dead skin layer, and reach the living layer (dermis) of the finger’s skin to directly read the fingerprint pattern. Because it penetrates deep into the dermis, the sensor can capture more real data, and is not easily affected by the dust on the finger surface, which improves the recognition accuracy and effectively prevents recognition errors.
Capacitive fingerprint sensors include semiconductor pressure-sensitive sensors, semiconductor temperature-sensing sensors, and the like, among which, semiconductor capacitive fingerprint sensors are the most widely used.
Unlike optical devices that use manual adjustment to improve image quality, capacitive sensors use automatic control technology to adjust fingerprint image pixels and the sensitivity of the local area of the fingerprint, and combine feedback information in different environments to generate high-quality images. Thanks to the local adjustment capability, even images with poor contrast (such as areas where a finger is lightly pressed) can be effectively detected, and the sensitivity of these pixels is increased at the moment of capture, resulting in high-quality fingerprint images.
The advantages of semiconductor capacitive fingerprint sensor are:
- Good image quality
- Generally without distortion
- Small size
- Easy to integrate into various devices
The electronic signal it sends will pass through the surface of the finger and the dead skin layer to reach the living layer (dermal layer) of the finger skin, and directly read the fingerprint pattern, thus greatly improving the security of the system.
However, the semiconductor silicon sensing technology also has the disadvantage that it will be disturbed by static electricity, but it can be solved by grounding during installation. In the past, the cost was relatively expensive. In recent years, the cost has dropped significantly, and the cost of the optical sensor is getting closer and closer.
It is the most ideal fingerprint identification technology at present. For example, the security access control system of high-risk security places such as bank vaults and prisons, the fingerprint machine using semiconductor silicon sensor recognition technology is used for the front-end living fingerprint recognition of access control, instead of the traditional password, card swipe, and optical fingerprint machine, so as to truly achieve the uniqueness of identity recognition , make sure nothing goes wrong.
Ultrasonic fingerprint collection is a new type of technology. The principle is that ultrasonic waves have the ability to penetrate materials and generate echoes of different sizes with different materials (when ultrasonic waves reach the surface of different materials, the degree of absorption, penetration and reflection is different. ). Therefore, using the difference in the acoustic impedance of the skin and the air, the location of the fingerprint ridge and the valley can be distinguished.
What can Huifan Technology provide to customers?
Huifan Technology has 16 years of experience in the biometrics industry and can provide customers with specific products and integrated biometrics solutions.
From the sensor module, it can be divided into optical fingerprint sensor, capacitive fingerprint sensor (the definition has been emphasized above)
According to the size of the acquisition window, there can be FAP10, FAP20, FAP30, FAP45, FAP60
At the same time can provide various certificates, FBI, PIV, CE, FCC
What can Huifan Technology do for customers?
Hardware: The hardware interface of the fingerprint sensor produced by Huifan Technology is sufficient and can be customized according to your own needs
Software: Huifan Technology will have a built-in fingerprint scanner demo apk when it leaves the factory. This apk will develop all the basic functions. At the same time, we can provide users with requirements and SDK for customers who need secondary development. Customers can develop solutions that meet their needs according to their own needs
Data: Once an order is placed, the data will be used for life. You have placed an order with Huifan, and Huifan will provide you with hardware disassembly video, software operation video, appearance introduction and promotion video for free. Truly integrated services.
Fingerprint Scanner Features
Built-in lithium battery
Two-finger scrolling collection
Support multiple systems, android, linux, ios, windows
Huifan Technology Fingerprint Project Customization Process
- logo customization
- Packaging customization
- Software customization
- Hardware customization
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