How the fingerprint sensor works?

Friends did you recently bought any mobile which is above 7k?

If yes then you must got a fingerprint sensor which enhance your privacy and security of your mobile..

So Guys did you ever thought about it,that how fingerprint sensor works

So friends if you don't know about that then this article is only for you

At first fingerprint sensor is of two types

1.Optical Scanner

2.Capacitive Scanner

All Scanners are based on one theory that to recognize your finger print by generating an image of your fingerprint.

1.Optical Scanners

Friends you must this kind of Scanner at many offices,ATMs,Adhaar Center etc.

Optical fingerprint scanner

This kind of scanners are based on generating and processing of fingerprint optically.

That means a light is emitted from this device and when we put the finger on that 

Light is projected on our finger's ridges and valleys.

As you see on the above diagram

After that the light is reflected back to the sensor and sensor make an image of our fingerprint and processor process this and put the data on the system.

But as this is an optical scanner so the processing and recognition is quite slow.

In this type of technology anyone can theft your fingerprint impression on a sheet and may misuse that impression so this is not safe too much.

As this only process image , this sensor can't detect that whether the object is a impression or a real finger

That's why a new type of scanner is came to fill this cons. I.e Capacitive Fingerprint Sensor.

2.Capacitive Type

Like the optical scanner ,Capacitive scanner also based on the image processing,

But something advanced.

i.e it depends upon electrically generated image processing which enhance the accuracy and security.

Capacitive Fingerprint Sensor

This type of sensor doesn't emit light to read the ridges and valleys

This sensor uses many semiconductor chips which are as small as our each ridge.

There are many chips are fitted into it.

When we put the finger on that then the chips on which our ridges were placed becomes inactive or a voltage breakdown occurs.

I mentioned a circuit diagram and working mechanism of Capacitive Fingerprint Sensor below

Circuit diagram during voltage breakdown

Working mechanism

As you see above the chips which are free became active and other were being inactive untill the finger is removed.

In this mechanism a sensor can make a electrical image of your fingerprint and the software started match it , if the image is matched above 90% then it unlocks your phone quickly.

Now you must have a question that The recently launched Vivo's X21 phone has a inbuilt fingerprint sensor , i.e under the phone's screen.

So how is this possible.?

So friends this impossible technique was made possible by a company named SYNAPTICS

SYNAPTICS official Logo

Vivo's X21 Device with in-display fingerprint scanner

This company manufactures the fingerprint sensors.

But after many days research this company made this possible i.e under screen fingerprint sensor.

But this technology only works on phones which have OLED DISPLAY.

Because in normal LCD display we must fit a backlit on the back of the display so fitting up a fingerprint sensor behind that is like a dream

But in OLED Screen there is no requirement of backlit.

So a fingerprint sensor was fitted behind that display.

Actually this fingerprint is a Optical type.

That means it emit a invisible light which projected on our finger's ridges and valleys,then it processed it and unlock your device.

But the main part is missing I told you that mobile phones use Capacitive touch screens (Click here for more information) in my previous post.

So although this sensor is optical type but with the implementation with capacitive touch screen,It works as a Capacitive Fingerprint scanner.

So friends Thanks for read my article and Hope you get all information about fingerprint scanner