How does a fingerprint scanner work on a smartphone…………
What
is Finger Print Sensor?
Fingerprint scanners are security systems of biometrics. They are
now used in police stations, security industries and most recently, on
computers. Everyone has marks on their fingers. ... These marks have a pattern
and this pattern is called thefingerprint.
Application of FingerPrint Sensor
Ø Mobile Phone Unlock
Ø App Lock
Ø Security For Payment Purpose
Ø Click Photo Snap Via Touch Finger
print sensor
Working of fingerprint scanners may seem very
complicated but it is very basic and easily understandable. As a matter of fact,
with good enough understanding and enthusiasm, you could build your very own
sensor at home. Yes, you would have to buy some parts online though.
There are a few different types of scanners. All of
them basically try to find ridges and valleys on your fingers by one mechanism
or other Optical sensor uses light, Capacitive uses capacitive circuits.
These ridges and valleys are responsible for formation
of certain unique designs on your fingers called Minutes.
Basically
it recognizes patterns from the highs and lows from your finger. Each finger
has a unique patter. Now how it does this in depth depends on which type of fingerprint scanner the phone uses. There are 3
basic types of fingerprint scanners
Optical fingerprint scanner
These type of scanners have a source
light, which emits laser light to a prism. The prism is placed in such an angle
to this light that due to total internal reflection, the light emitting from
the source touches a side of the prism and reflects back. This reflected light
is then captured by a sensor. This captured light is then converted into a
digital image and used for validation. When you place your finger on the
sensor, you block the total internal reflection from the source, thereby
helping the sensor to take a high resolution picture
Capacitive fingerprint scanner
These type of scanners discard
the source light and the prism. They directly use the sensor and charge coupled
device under metallic plate. They receive charges from your finger. The ridges
of your finger conduct electricity and valleys don’t. This creates a charge
pattern in the CCD, which can be used for validation.
Ultrasonic fingerprint scanner
These sensors emit ultrasonic waves
from a source which can travel through glass, metal, etc. but gets reflected by
your finger. These reflected waves are captured back by its receiver and a 3D
model of your fingerprint is created for validation.
All of
these sensors have their advantages and limitations. Watch video for more
detailed explanation.
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