Biometric security systems are here to stay. At the moment, unlocking by fingerprint is the most widespread (who knows if in the future our eyes will suffice to unlock the mobile) and it is a more secure system than the PIN to access the terminal, but What a rage when the fingerprint sensor on the screen fails, right?
There are times when this technology does not work as it should because there are several factors that work at the same time to compare the data and allow us to access our mobile. So, if for whatever reason you notice that the unlocking is slow or it doesn’t always catch you the first time, don’t worry because it has a solution and we’ll tell you how to improve the accuracy of the on-screen fingerprint sensor.
How on-screen fingerprint readers work
Before seeing how to improve the accuracy of the fingerprint reader, We are going to talk about the two current technologies present on the on-screen sensors. They are very, very different solutions and both of the most curious.
On the one hand, there is the optical sensor. It is the one with the most presence in the market and we see them in both mid-range and high-end mobiles and premium mobiles. In this there is no distinction, since it is used in a wide range of devices.
And it works in a very curious way. It consists of a camera that is located at a very specific point under the panel (it is usually in the part closest to the chin) and, basically, what it does is a photo of our footprint to compare it with the numerous photographs of the same print that are taken at the time of configuration.
I wish the sensor was a bit more centered, but the Xiaomi 13’s optical sensor is lightning fast.
As the “camera” needs light To correctly register our fingerprint, the sensor area lights up brightly when we place our finger on it. It is an accessible technology for brands, but it presents three impediments:
- The detection area is very small. In the end, the camera is small and cannot cover a very large area. That is why we also have to be precise when placing the finger.
- Although it depends on the processing and the mobile system, it is a technology that is not as fast as others that capture our footprint.
- The camera hole is very, very small, which is why it is a somewhat less secure technology than the one we will discuss below (but more secure than the four-digit PIN, as Google is trying to convey).
On the other hand, we find ultrasonic sensors. This technology is somewhat more expensive than that of optical sensors and, therefore, we usually see it in high-end and premium mobiles.
Galaxy S23 ultrasonic sensor.
Samsung is a promoter of this technology in its flagshipslike the Galaxy S23 Ultra, and Vivo is another example, with a great implementation in the Vivo X80 Pro that allows a huge detection area and even multi-fingerprint.
Precisely, that the area is larger is one of the advantages and, in addition, the area does not light up (so it does not dazzle us when we are in bed in the dark). Because? Well, why? here there is no camera, but an ultrasound system and a tiny microphone.
The area of some ultrasonic sensors is so large that it allows you to define unlock areas for apps.
When we support our finger, the ultrasound “maps” our footprint taking into account minute variations in the depth of the grooves of the bud. The microphone collects the data back and those signals or impulses are compared with the one we recorded for the first time in the system.
In addition to being a system -generally- faster than the optical one, it is also more secure and less prone to failures by the speed of ultrasound.
The trick so that the fingerprint sensor on the screen does not fail
Given the theory, let’s go with my problem. Because of my work, I analyze a lot of mobile phones and I have to admit that I’m not very fond of facial unlocking on Android as long as it’s not accompanied by an advanced detection system (and it doesn’t happen in the vast majority of mobile phones).
So, I always use the fingerprint to unlock the device. In the high range it almost always works well, but in the mid-range is where I suffer the most And these days, analyzing the Xiaomi 13 Lite, I have found a problem that I have encountered in other mobiles in this segment: the fingerprint sensor is erratic. At least in my case.
It is located at the same point as the Xiaomi 13, and that one works perfectly, but in the Lite version, at least in my unit, not so much. So, I resorted to the trick of registering the same fingerprint several times.
It has no more mystery. And it is that, It is one of the tricks to make the fingerprint sensor on the screen faster and it does not fail and it is something that I have put into practice both in several Xiaomi and, for example, in the Pixel 6a, which was also somewhat lazy.
Generally, Mobile phones allow you to register five fingerprints so I recommend that you register three for the thumb of your dominant hand and two for the thumb of the other hand to improve both accuracy and speed.
All you have to do is go to the ‘Security’ section on the ‘Settings’ screen of your device and add as many prints of the same finger as the terminal allows. In my case, I have added the same fingerprint five times and the result is that the unlocking has not failed me again.
In some mobiles you cannot register the same fingerprint several times.
Eye! This trick does not work with all ultrasonic sensors. For example, I tried to register the fingerprint a second time on my Vivo X80 Pro and he told me no, that it already existed. With the Galaxy S23, however, you can register the same fingerprint more than once. But hey, I don’t think you have problems with an ultrasonic sensor and, if so, what we recommend is that you delete the data of that fingerprint and register it again.
And little more, we hope that this trick for the on-screen fingerprint sensor will help you to avoid having more “wrong fingerprints” that force you to end up unlocking the mobile using the PIN.
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