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Fingerprint scanner is a hardware device that obtains a person’s unique fingerprint information and forms a complete feature algorithm through a series of encryption algorithms to compare the information. There are roughly four types of fingerprint scanners that you know of, namely optical fingerprint scanners, capacitive scanners, ultrasonic fingerprint scanners, and thermal fingerprint scanners.

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What is an Optical Fingerprint Sensor?

Optical fingerprint scanners can be divided into two types, namely traditional optical fingerprint scanners and prism-free optical fingerprint scanners;

Traditional optical fingerprint scanners:

The traditional optical fingerprint scanner uses frustrated total internal reflection (FTIR); it is the longest-standing device;

Working principle:

See Figure 1. When you touch the top of the prism with your finger, the fingerprint ridges are in contact with the surface of the prism, but the fingerprint valleys are not in contact with the prism. At this time, the light source enters the prism from the lower left, and total reflection occurs in the valleys and scatters at the ridges. The light is emitted from the right side of the prism and focused onto the image sensor through the lens. In the fingerprint image, the ridges are dark and the valleys are bright, and the fingerprint is identified by the bright and bright.

PICV1

The first version of the optical fingerprint scanner was too large and inconvenient to use, which was not very friendly to the devices that needed to be built-in;
Based on this, the number of refractions was changed from the previous single refraction to multiple refractions, which reduced the size and cost at the same time.
See Figure 2

f2

Prismless optical fingerprint scanner:

The second type is a prismless scanner, which uses TFT technology. By completely removing the prism and lens, the optical signal is directly transmitted to the inner surface of the acquisition device. This can reduce the size of the device.

How it works:

What are Optical Fingerprint Sensors Made Of?

From the above principles, we can see that the optical device is composed of accessories;

• Light source – illuminates the device and locates the ridges and valleys
• Glass cover: protects the device from friction damage.
• CCD or CMOS: used to take fingerprint images
• Motherboard: used to process the fingerprint images taken
• Interface: serial port or USB, connect to third-party devices or transmit data

Steps for Optical Fingerprint Scanning:

• Clean your fingers： Make sure your fingers are clean. If your fingers are dry, you can use some hand cream. If your fingers are wet, you can use alcohol wipes to clean them.
• Turn on the device： Connect the USB device, or turn on the device.
• Place the fingerprint：Follow the instructions from the device and place your finger on the fingerprint scanner
• Get the fingerprint：The device will work in the background to get your original fingerprint image (the principle can be referred to the previous section)
• Form a feature template：Upload the obtained original fingerprint image to the computer, and form your fingerprint template through the fingerprint algorithm
• Compare and identify：Query the obtained fingerprint feature template in the database

Pros and Cons of Optical Fingerprint Sensors

Pro:

• Optical fingerprint scanners have strong anti-static ability,
• and good system stability.
• High cost performance

Cons:

1. Latent fingerprints will appear, reducing image quality
2. Hardware equipment will wear out over time and use
3. Low ability to reject fakes
   

Applications of Optical Fingerprint Sensors

• Access control and attendance
• KYC
• Fingerprint payment

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What is a Capacitive Fingerprint Sensor?

Capacitive fingerprint scanner is a sensor-based solution. By pressing your finger on the chip, an electric charge is generated between the finger and the capacitor, and then the charge is converted into digital information.

What are Capacitive Fingerprint Sensors Made Of?

1. Sensor: used to measure capacitance and convert it into numerical value
2. Motherboard: forms a feature template by analyzing the numerical value
3. Interface: transmits data between computers or supplies power to the device

How Do Capacitive Fingerprint Sensors Work?

The technology of capacitive fingerprint scanner is to identify by the difference between the fingerprint and the capacitance.
The electrodes on the sensor can sense the capacitance change when the fingertip is pressed, and the characteristic image of the fingerprint is extracted by measuring the value of the capacitance change.

 Key Steps for Capacitive Fingerprint Scanning:

1. Clean your fingers: Make sure your fingers are clean. If your fingers are dry, you can use some hand cream. If your fingers are wet, you can use alcohol wipes to clean them.
2. Turn on the device: Connect a USB device or turn on the device.
3. Place the fingerprint: Follow the instructions from the device and place your finger on the fingerprint scanner. Make sure your fingertips are in full contact with the sensor surface and change the strength.
4. Get the fingerprint: The device will work in the background to get your original fingerprint image (the principle can be referred to the previous section)
5. Form a feature template: Upload the original fingerprint image to the computer and form your fingerprint template through the fingerprint algorithm.
6. Comparison and recognition: Query the acquired fingerprint feature template in the database

Pros and Cons of Capacitive Fingerprint Sensors

Pro:

1. Liveness recognition
2. Шағын өлшем
3. Low power consumption

Cons:

1. High cost
2. Static interference

Applications of Capacitive Fingerprint Sensors

1. Bank vault
2. Prison
3. Access control front-end identity recognition and authentication

Ultrasonic Саусақ ізі сканері

What is  Ultrasonic Fingerprint Sensor?

Ultrasonic fingerprint technology is a new technology that uses sound waves to transmit signals to the fingertips and captures the signals back for processing.

What are Ultrasonic Fingerprint Sensors Made Of?

Transmitter: generates sound wave pulses

Receiver: checks the pulses and gives a response

How Do Ultrasonic  Fingerprint Sensors Work?

Ultrasonic sensing is based on sending a sound wave signal directed at the fingertips, capturing the returning sound wave signal, and calculating the fingerprint ridges from the echo signal.

Pros and Cons of Ultrasonic  Fingerprint Sensors

Pros and Cons of Ultrasonic  Fingerprint Sensors

Pros:

1. Low requirement for finger cleanliness
2. High precision

Cons:

1. Long collection time
2. Price and safety

Applications of Ultrasonic Fingerprint Sensors

Full screen mobile phone

Thermal Fingerprint Scanner

What is  Thermal Fingerprint Sensor?

Thermal fingerprint scanner is a device based on temperature

What are Thermal Fingerprint Sensors Made Of?

Sensor: The sensor is the core of the fingerprint scanner and is responsible for detecting the heat difference of the fingerprint.

Mainboard: Converts the captured fingerprint image into a digital signal to form a fingerprint feature template.

Shell: Protects the sensor and motherboard for easy use.

Interface: Used to transmit data and power the device.

How Do Thermal Fingerprint Sensors Work?

Thermal sensors are devices made of pyroelectric materials that analyze different image features based on the current differences generated by different fingers; the ridges of the fingerprints touch the sensor surface, and the valleys of the fingerprints touch the sensor surface, but there is a certain distance between the fingertips. The temperature difference generated is different due to the different distances. The sensor is kept at a high temperature through electrical heating to increase the temperature difference between the sensor surface and the fingertips. When the fingers touch, the temperature difference will produce an image, but as the temperature disappears, the image will quickly disappear, so this technology is not widely used.

Pros and Cons of Thermal Fingerprint Sensors

Pros:

1. Small sensor size and area
2. Short acquisition time

Cons:

1. Large temperature limitation
2. Expensive

Applications of Thermal Fingerprint Sensors

Access control
Attendance management

Түйіндеме

The above are the 4 different types of fingerprint scanners, from which you can get the information you want
HFSECURITY can provide you with a complete fingerprint scanner solution according to your needs