3. Ultrasonic Scanners.
This is the latest technology entering in some ofthe new smartphones. As the name suggests, it
uses ultrasonic sound waves to detect the fingerprints.It contains a transmitter and receiver of
ultrasonic waves. The transmitter transmits ultrasonicwaves when a finger is placed over the
scanner. Some of the waves are absorbed, and othersare reflected according to the ridges and
gaps in fingerprints. The reflected wave is detectedby the receiver. The receiver is a device
which can detect mechanical stress in terms of intensityof ultrasonic waves coming from a
different area of the finger and thus calculatingthe structure of the fingerprint. In this process,
the detailed 3D structure of the fingerprint is made,making it a more secure alternative to a
capacitive scanner. The detail of the 3D structureis directly proportional to the time given to
scan the prints, as more time means more ultrasonicwaves transmitted and received.
Apart from being highly secure, another advantageof this is that it can easily be integrated into
the screen directly so we can get infinity screenfeatures.
Some disadvantages of an
ultrasonic scanner are that it
takes longer to scan
fingerprints as because of the
reason described above. Also,
we all use protective glass
(gorilla glass) to protect the
screen of the phone, but the
scanner is not able to detect
the fingerprint accurately
because of this glass, making
this huge opportunity to
improve for developers.
Also, there are other options if one wants to havean in-display sensor like optical-capacitive
sensors. As Ultrasonic scanners send ultrasonic rays,the rays have to pass through the display
or glass. Now the rays can pass through 800 micronsbut when an extra screen protector is
added, it will cause a problem with this scanner.
But a drawback of using an optical-capacitive scanner,as it has to lighten up the finger for
prints, it only works with OLED displays because thereare gaps on the backside of the display
for light to escape. This method is more secure thanjust optical as the capacitive scanner scans
the fingerprints and it can easily be scaled up toincrease the area to detect the fingerprints.
So above, we discussed the different types of scannersused to detect fingerprints. But, now
and then, we see that different smartphone companiesare competing to make biometric
scanner fast