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Debate of the Week

[Discussion] [#17 Debate of the week] Under screen fingerprint Vs Physical fingerprint : Which one do you prefer?

2019-01-27 04:26:10
16101 165

Hi Mi Fans!!!   
We are here with another interesting debate, Underscreen fingerprint sensor Vs Physical fingerprint sensor. As you may know, many cell phone brands have come up with the new technology of In screen fingerprint scanner or otherwise called the Under screen fingerprint sensor technology. As soon as it was released, it became a sensation among gadgets lovers as it gives a much more premium feel to the device. But still, this technology has a bit of disadvantage compared to the conventional one.

Today we will try to explain both the topics one by one, about its merits and demerits and it's up to you Mi Fans to decide which is better.

So Let's get started...

Physical Fingerprint Sensor

A fingerprint scanner, capacitive or optical works on the basis of patterns of ridges and valleys found in human fingertips. These ridges and valleys are responsible for the formation of certain unique designs on your fingers. fingerprints are a unique marker for a person, even for an identical twin. And while two prints may look basically the same at a glance, a trained investigator or an advanced piece of software can pick out clear, defined differences and so can a fingerprint scanner.

The physical fingerprint scanner which is quite common in the budget device to higher uses the uniqueness provided by the fingerprint of humans. It uses a capacitive circuit which can make use of electric current patterns with respect to the valley and ridge of the fingerprint.

How it works...

There are two conductor plates form a basic capacitor, an electrical component that can store up charge. The surface of the finger acts as a third capacitor plate, separated by the insulating layers in the cell structure and, in the case of the fingerprint valleys, a pocket of air. Varying the distance between the capacitor plates (by moving the finger closer or farther away from the conducting plates) changes the total capacitance (ability to store charge) of the capacitor. Because of this quality, the capacitor in a cell under a ridge will have a greater capacitance than the capacitor in a cell under a valley.

To scan the finger, the processor first closes the reset switch for each cell, which shorts each amplifier's input and output to "balance" the integrator circuit. When the switch is opened again, and the processor applies a fixed charge to the integrator circuit, the capacitors charge up. The capacitance of the feedback loop's capacitor affects the voltage at the amplifier's input, which affects the amplifier's output. Since the distance to the finger alters capacitance, a finger ridge will result in a different voltage output than a finger valley.

The scanner processor reads this voltage output and determines whether it is characteristic of a ridge or a valley. By reading every cell in the sensor array, the processor can put together an overall picture of the fingerprint, similar to the image captured by an optical scanner.

Advantages of Physical/ capacitive fingerprint scanner :

  • It is cheaper technology and can be implemented with less expense. So viable in low and budget devices.
  • It is faster than an optical scanner.
  • It requires a real fingerprint-type shape, rather than the pattern of light and dark that makes up the visual impression of a fingerprint. This makes the system harder to trick.
  • Since they use a semiconductor chip rather than a CCD unit, capacitive scanners tend to be more compact than optical devices.
  • In many cases, they are more accurate and responsive than optical sensors.

Disadvantages of Physical/ capacitive fingerprint scanner :

  • It cannot give the premium feel that an under display fingerprint scanner can give.
  • Takes up extra space on the device.
  • It cannot be protected by any means, scratchable scanners are a matter of concern.
  • Can be tentative in cases when fingers are wet or oily.

Under-display Fingerprint Sensor

The under-display fingerprint scanner used by most brands is optical sensors so they work using the same principle but different method. The optical scanner has an image sensor that captures a picture of the fingerprint on the scanner and compares it to that stored on the phone. If it matches, it unlocks the phone.
An in-display fingerprint scanner currently only works with OLED displays as the sensor can scan the fingerprint through the OLED dots. An LCD display uses a backlight which won’t allow the sensor to see through the screen.

How it works...
As I have said before, it works only OLED displays and not LCD displays.  In this sensors, they light up the finger to take the image of the finger and compare it with already recorded one. After placing the finger it passes the light and scans the finger and takes around half a second to unlock the device. The fingerprint sensor captures the image of the fingerprint and turns into an equation based on the contrasting points of fingerprint ridges. The sensor is designed to work pretty much covered and in close range, unlike the colourful camera sensor.
The Under display fingerprint scanner is considered as a symbol of premium feature now. But still, it is restricted to OLED displays which limits its application to high-end devices.

Advantages of Underscreen Fingerprint Scanner :
  • It gives that premium look to the device, good who don't like to be stuck in older technologies
  • It can be protected by a screen guard or tempered glass
  • It doesn't take up extra space of the device as it is implemented under the screen.

Disadvantages of Underscreen Fingerprint Scanner:

  • It is expensive to implement as it is mandatory to have an OLED display other than LCD backlight screen which is cheaper.
  • In case of a screen crack, the fingerprint sensor mostly can't get the clean image of the finger so usually fails in those cases.
  • It is less responsive and accurate in most cases compared to the conventional one.

So, now it's your time to decide whether you prefer the Under display fingerprint scanner or Physical fingerprint scanner. Do participate in the debate and let us know.

Previous debates :


End Time: 2019-04-27 02:39:00
For 57
Under screen fingerprint scanner is the way to the future and gives the phone a more premium feel
Against 85
Physical Fingerprint scanner works more accurately than the Underscreen Scanner.


Number of participants 1 Experience +10 Pack Reason

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2019-01-27 04:26:10
Favorites148 RateRate
Debate of the Week
Weekly Debates on Hot topics in the smartphones and Tech
40 Article Description     345 Subscribers
i think physical fingerprint scanner is good
2019-01-27 06:31:39

Semi Pro Bunny

SandipBani | from app


In screen is better new style
2019-01-27 15:46:19

Advanced Bunny

1792355762 | from app


Latest Technology
2019-01-27 16:47:34

Pro Bunny

Psy Element | from MI 8


i think physical fingerprint scanner is good

both are good for scanning
2019-01-27 17:39:28
Nice info
2019-01-27 20:53:24


Mayank #1 | from app


I prefer in display fingerprint sensor as it gives smartphone more premium feel.
2019-01-27 23:37:09

Master Bunny

17418ajish84822 | from Redmi Note 4


underscreen definitely
2019-01-28 03:45:42
It's interesting
2019-01-28 03:51:39
Under screeen fingerprint scanner looks pretty interesting
2019-01-28 04:47:39

Master Bunny

vidya5194905456 | from Redmi Note 5 Pro


any way both are advantages and disadvantages.i think physical scanner is better it also cost efficient.
2019-01-28 06:38:14
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