Explained: Different fingerprint scanners available on smartphones and how they work – Times of India

Smartphones come with various security systems like — PIN, Password, facial recognition and others to keep your device safe from unwanted access. The fingerprint scanner is also a type of electronic security system that uses fingerprints for biometric authentication to grant users access to their devices. Fingerprint scanners are now a common security system that is present in most mobile devices.
What are fingerprint scanners?
We all know that every human has their own unique fingerprints, this property helps devices to successfully identify individual users. As technology advanced, manufacturers were able to incorporate fingerprint scanners (or sensors) as an optional security feature for mobile devices. Fingerprint scanners have now become a common thing in most mobile devices as users enjoy them for security and convenience.
These sensors capture the minute curves and edges of a finger and use the device’s pattern analysis/matching software to process the information and compare it to the list of registered fingerprints. Access to the device is granted only when there is a successful match and the user’s identity has been verified. The method of capturing data varies depending on the type of sensor that has been used on the device. Now, let us discuss the different types of fingerprint scanners and how they work.
Different types of fingerprint scanners available on smartphones
Optical Scanner: Optical scanners usually make a photocopy of the finger. Most scanners light up the finger to deliver perfect contrast of lines as the light-sensitive sensor registers the information to produce a digital image. Most fingerprint scanners that are connected to PCs use optical sensors.
Capacitive Scanner: Capacitive scanners use electricity instead of light to determine fingerprint patterns. The device measures the charge of a finger as it rests on the touch-capacitive surface. The sensor determines which curves of the finger are showing a change in capacitance and which ones are not producing any change at all. All this data is then used by the sensor to map out fingerprints accurately. Most smartphones use capacitive sensors for fingerprint scanning.
Ultrasonic Scanner: Ultrasonic scanners use sound waves to function. It is very similar to the echolocation process used by bats and dolphins to find and identify objects. The hardware is designed to discharge ultrasonic pulses and measure the amount that bounces back. The curves and edges present on your fingers reflect sound differently, ultimately helping the ultrasonic scanners to create a detailed 3D map of fingerprint patterns. The 3D ultrasonic in-display fingerprint sensor developed by Qualcomm has been adopted inside Samsung devices.
Optical-capacitive scanners: Ultrasonic fingerprint scanners are not the only option for the manufacturers to hide the sensor in the display, optical-capacitive fingerprint scanners can also be used for the same purpose. These scanners include both the “real touch” requirements of capacitive sensors and the speed and energy efficiency of optical scanners. This technology is embedded into mobile devices by inserting a sensor under the display that detects light reflected by a fingerprint back through the gaps in the pixels.