One touch and unlocked. One touch and paid. A touch and recorded. The comfort that gives you a fingerprint reader on the mobile is something that is appreciated but that little thing behind us, front or side of your device, how does it work?
The first thing is to know that there are several types of fingerprint readers: Optical, capacitive and ultrasonic. Then we will see what the function of each of these three.
optical readers, as a camera
Optical fingerprint readers are quite similar in operation to an ordinary camera photos. A sensor placed in the reader captures an image of your fingerprint as if taking a photo and she recognizes the lightest and darkest areas to see the shape of the footprint.
Confidence in this type of reader depends on the resolution of the sensor, the ability to create a fingerprint image as detailed as possible and then compared. But nevertheless they are not quite sure readers since it is not able to differentiate between a real mark in 3D and a photo of a footprint in 2D.
Capacitive readers, capacitors that store your mark
The capacitive readers are most commonly used today in mobile phones. They use a lot of tiny capacitors that store energy depending on the shape of the footprint.
Therefore, if you put your mark on one of these sensors, capacitors outgoing touch your footprint will have a burden and they will not have another load, forming a fingerprint in detail with the recesses of your mark.
However these sensors are also more expensive for the use of hundreds of capacitors for reliable footprint. Some implementations of this type of reader save on number of capacitors need to drag your finger over rather than simply posarlo.
The more capacitors, higher resolution footprint, higher reliability and higher price.