Fingerprint ID

                                Fingerprint ID Working 

We all know , its a Scanner. but ever thought ,how it consumes our finger's details with the help of sound or from beneath the screen !

well , you should. whatever the reason is , you have to find it in your way in the sake of the technology growing today.

"Food for today . Technology for Tomorrow."

so here it comes.

First of all . our fingers can be divided in to three types generally .

Like ARCH type, in which the pattern starts from the one tip to another tip continuously.

second type is LOOP , in which pattern starts form down and continuous till the middle and again turns till another side .

Third type is WHORL , in which the pattern is self-made circle.

To detect them , we have three types of fingerprint sensor , Don't think , it is in the basis of the three types of the fingerprints in different bodies. it is because the technology gap.

 1.                           optical sensor

optical sensor is the type of sensor , where a light comes from the source and read your fingerprint by the ups and downs right there on your finger and make a map.

again when you put your finger in the source circuit, it will match the fingerprint and get you granted if match . It is like a simple camera , it simply capture your finger's photos and matches it through its database.

the question is , how do it match !

we have ups (ridges) and downs(valleys) in our fingerprints. Again , there are places in our fingers, somewhere in the ridges end , they are divided in to two sub-ridges or a circle is made by them. or a small up is formed or even in case they are tie up with the valleys right there.so the scanner simply detects those regions and give them co-ordinates and measures the distance between them with the algorithms and the detection software. when you register your finger and put it from various angles , then the scanner do eliminate the common parts and make a map under the circumstances given above. then when further you give a print , it match according to the data base , and gives the output.

The fingerprint scanner with green or red light in the backside are the perfect example of these scanner. 

These  are not more secure till a date , as we can bypass them with simply a plastic card with our fingerprint on it. we can bypass it by using wax , making a fake fingerprint when it is in liquid state .

so for these security issues , capacitive sensor came to market.

   2.                             capacitive scanner

First this type of fingerprint system is started by apple in its iPhone 5s model.

sir and madam , 

all of you already know that we have ridges and valleys , and some gaps must be there in the region between them . the capacitive technology brings a pattern of the sensors or we can say micro sized conductors and capacitors smaller than the gaps of our ridges and the valleys in the source. and when we put the finger in the source , the conductors and capacitor sensors are  activated in the touch region of our ridges . It is because you must know , if you don't know , remember our body can conduct some micro ampere of current. so when the conductor are placed and get touched by the ridges , then the circuit is completed , the current flows hence the sensors are activated , and the angles we put our fingerprints in the time of registration , the scanner scanned them in the above process, eliminates common areas and process them as the OPTICAL SENSOR did. then  the mapping is finished  . and the next time put your finger in the scanner it will search for your data in the database and return the result.

the fingerprint sensors used in smart phones now a days are the capacitive sensors .it has also the demerit that , it cannot detect your fingerprints when they are wet , or when we have any dust in our finger.

so ultrasonic fingerprint system has arrived by QUALCOMM.

   3.                                 ultrasonic scanner

This type of fingerprint scanner is totally different from the other two scanners. The optical and capacitive and optical fingerprint scanners maps the finger ridges and valleys in a 2-D structure. but the ultrasonic scanner do it in the 3-D model. so we can say it constructs a 3-D map of our finger.

It uses ultrasonic sound for mapping the finger at the time of touching.

To capture the details of the finger , it consists of a transmitter and a receiver.an ultrasonic pulse is transmitted against the finger at the time of touching. some are absorbed by the body and the rest pulses from the ridges , valleys , unique points are collected by the receiver. to process the data , algorithm is used , that detects mechanical stress and calculate the intensity of the returning pulse. Scanning at the time registration , it avails all the physical structure of the finger and map a highly detailed 3-D structure  of your finger.

the main things those separate the ultrasonic scanner from the rest two , are. 

It is a 3-D structure based system , they are not. It is more difficult to make fool to this kind of sensor than a 2-D one.

Again the circuit system can work behind the scene , that means it can be imbedded in the home button , in the screen , or in the cover.

Another point comes out , that is it can be work in the wet hand , dusted hand.

You came up to the last reading this .

here is your bonus point .

Do you know , How the Under display fingerprint works ? 

under display fingerprint ID

To maintain high screen-body ratio , the fingerprint scanner has to be imbedded beneath the screen. So SYNAPTICS , a hardware company worked for a optical imbedded sensor for the fingerprint under the screen.

it uses the light emitted by the OLED display for register your fingerprint in the device. So only OLED panels are eligible till today for the kind of sensor.
we can rather say it is a combination of optical and capacitive scanner. this kind of sensor maps the user data by the optical method , with the help of light from the OLED panel . And at the particular time they verify it by the capacitive method . We cannot use the sensor in the LCDs , because LCD has a back light. there are no space for the sensor to work. again OLED has no back light panel.

But the another thing is that , we cannot fool it easily because , Being a OLED , it has pixels in its display panels and those are working as capacitive sensor. so we have to put our finger physically to gain the access. And the second limitation of the capacitive sensor is also resolved as the fingerprint will work in wet hand and dust hand. 

First VIVO get this concept to reality.

thank you

if you have any doubt or suggestion , Please comment below.

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