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How does in-display fingerprint scanning work

Fingerprint scanning has become the most popular smartphone protection method. Today it is normal for people to turn to biometric authentication to secure their phones, even more so as phones are becoming more and more integral to our everyday lives.

How does in-display fingerprint scanning work

Biometric authentication is your own biological code (fingerprints, iris, voice, facial recognition, etc). We implement it in our smartphones to make sure nobody else gains access to them. Even though pin codes, passwords, and patterns are still widely used, biometric authentication is evolving.

Some manufacturers have managed to build an in-display fingerprint scanner. It is a scanner inside your smartphone display that can recognize your fingerprint map. The only difference is that it’s not on the surface of the telephone. Instead, it is below. But how does it work?

How Do In-Display Fingerprint Scanners Work?

There are three main types of fingerprint scanners – optical, ultrasonic, and capacitive. However, only the first two are used in-display. In this section, we will examine their inner workings.

1. Optical Scanner

Optical sensors are the oldest type of sensors. They operate in a way that’s similar to taking a picture. Namely, the sensor captures the optical image (a photograph) and with the help of an algorithm detects the unique structure, surface, and contours. Based on this saved image, it can replicate the object and recognize it again.

The better the resolution of the scanner, the clearer the fingerprint will be. This type of scanner is two-dimensional and therefore easier to trick. Prosthetics, high-definition images, and other methods can fool the algorithm and give somebody access to your data. These types of scanners are not used so much anymore, although they are returning in some form with the growing popularity of in-display fingerprint scanners.

How Do Optical In-Display Scanners Work?

An optical sensor is embedded under the display of your smartphone. It uses optical methods to capture your unique fingerprint ID. Synaptics developed the ‘Clear ID’ sensor – the first optical in-display sensor, which was incorporated into the Vivo X20 smartphone.

This telephone has OLED panels which are the only way these scanners can work properly. When you put your finger on the display, the sensor will capture an image and unlock your device. So, if you put your finger on an OLED display, the light will shine over your fingerprint and capture a clear, high-resolution image of it.

The algorithm then looks at all the light and dark part of your finger and compares the images before it agrees to unlock your device.

How does in-display fingerprint scanning work

2. Ultrasonic Scanner

Ultrasonic scanning is the latest technology in fingerprint scanning. As the name suggests, it uses an ultrasonic transmitter and an ultrasonic receiver to create scans that are impossible to duplicate.

When you press your finger onto this scanner, an ultrasonic pulse transmits against it. A part of it bounces back to the sensor, but the other part remains in your pores, lines, and other distinctive features of your fingerprint.

Since this gives you a 3D image of your fingerprint, it is the most secure of the three methods.

How Do Ultrasonic In-Display Scanners Work?

Ultrasonic scanners are still a work-in-progress as its implementation has started only recently. The Samsung Galaxy S10 and Galaxy S10 Plus both have ultrasonic in-display fingerprint sensors. They are still not perfect as there are many things that can prevent them from working.

Since the scanner is embedded under the display, the ultrasonic waves need to go through a lot of layers. They have to move through the backplane of the display, then through glass, and in the end your screen protection before they finally arrive at your finger.

That’s why the function works well only when the screen is thin, and when there isn’t any protection. With some improvements in the future, we should see ultrasonic scanners become widely-used. They are the most reliable form of security after all.

How does in-display fingerprint scanning work

A Note About Capacitive Scanners

Besides the two mentioned types, there are also capacitive scanners. They are considered the most secure and most popular among smartphone users. Unlike ultrasonic and optical, capacitive scanners aren’t in-display. They require a direct touch of your finger, without any obstacles like glass in between.

They use a piece of electronics called capacitor to scan fingerprint data. When you place your finger on the scanner, it will charge and track your fingerprint map.

If the smartphone has enough capacitors, you will get a high definition scan that is hard to trick. That is why it’s considered the safest. Capacitive scanners are used in some of the more recent smartphone models. You will find them embedded in the home button of an iPhone, or on the back side of some phones.

Pros and Cons of In-Display Scanners

In-display sensors look great. They are also thin and blend in nicely with the modern, slim smartphone design. These scanners are also conveniently placed in the front of the device, so you can access them easily.

On the negative side, if you have any thicker screen protection, there is a chance that they could malfunction. Also, they take a bit longer to unlock compared to regular sensors. However, as the technology becomes more popular and more smartphone manufacturers decide to incorporate it, we should see major improvements in this regard.

In-display fingerprint scanning is like magic! You contact the display, it reads your fingerprint, after which it immediately unlocks your telephone. Let’s take a look at the expertise behind the magic.

Transferring Away from Bodily Scanners

Fingerprint scanning, like different types of biometric recognition, is nothing new to computing gadgets. Whereas scanners have been on laptops for a number of a long time now, the primary cell phone to have one was the Pantech GI100 in 2004. They got here again in a giant means through the smartphone period, although, as a result of ever-growing want to guard the info in our pockets.

In 2013, the Apple iPhone 5S grew to become the primary main cellular system within the U.S. market to have a fingerprint scanner with the launch of Contact ID. Though Apple has since phased changed this characteristic with facial recognition, fingerprint scanners grew to become commonplace on all smartphones. Most positioned the biometrics on the again or facet of the system.

Over the previous few years, different telephone producers have additionally phased out bodily fingerprint scanners. Like Apple, some have eliminated fingerprint verification completely, however others have changed the bodily pad with a scanner within the display. This lets you unlock your telephone by putting your finger on a particular space of the telephone’s show.

RELATED: How Safe Are Face ID and Contact ID?

The In-Show Scanning Course of

Typically, the scanning course of is similar, whether or not it’s a bodily or in-display design.

Often, a particular a part of the display has a scanning space beneath it. While you place your finger over the scanner, it takes a snapshot of your finger’s sample with a digital camera or different sensor. It then matches it to the biometric knowledge in your telephone. If it’s a match, your telephone will immediately unlock.

One of many greatest issues in-display scanners is the scanning space is comparatively small. It’s usually a small field within the decrease quarter of the show. Cellphone producers usually embrace a information within the software program to point out you the place to put your finger. This may seem when the display is turned on or in case your system helps always-on shows.

The scanning course of will be instantaneous or very gradual. That is possible as a result of giant variations between the 2 scanning applied sciences.

RELATED: Learn how to Make Your Cellphone’s Fingerprint Reader Extra Correct

Optical vs. Ultrasonic

There are two major varieties of in-display fingerprint scanners: optical and ultrasonic.

Optical scanners shine a shiny mild in your finger (it usually seems on-screen as an animation). It then takes an image of your illuminated fingerprint with a digital camera beneath the display and makes positive it’s registered. Whether it is, the telephone unlocks.

Many suppose the optical scanner is the much less safe of the 2 applied sciences as a result of it makes use of a easy digital camera to seize a fingerprint picture. Nevertheless, it’s usually considerably quicker. Relying on software program optimization, it may be simply as quick as even one of the best bodily fingerprint scanner. You’ll discover optical scanners on OnePlus telephones and plenty of midrange gadgets.

Ultrasonic scanners are sometimes thought to be the higher of the 2 applied sciences. As an alternative of sunshine, they use ultrasonic sound waves that bounce off your finger to seize an correct 3D picture. This system is just like that utilized in medical ultrasound machines.

Ultrasonic scanners are considerably safer than opticals as a result of it’s a lot harder to faux a 3D picture of a fingerprint. They’re additionally extra secure than optical scanners and work in tougher circumstances, resembling when your arms are moist or soiled. You’ll can discover these mini ultrasounds in high-end gadgets, like Samsung’s Galaxy collection.

RELATED: The Finest Samsung Galaxy Options You are Most likely Not Utilizing

The Way forward for Seamless Tech

In-display fingerprint scanners are half of a bigger plan by smartphone producers to attenuate seen intrusions. These embrace buttons, cameras, sensors, audio system, ports, and unused bezel area.

Together with the rise of in-display scanners, corporations have additionally begun including pop-up, front-facing cameras to enhance the display-to-body ratio. This coincides with the removal of headphone jacks, and firms competing to create true wi-fi earbuds for his or her telephones.

Sooner or later, extra options could be migrated beneath the display. Below-display audio system assist you to hearken to calls and stereo audio with none seen speaker grills. There’s additionally an under-display digital camera that lets you take portrait images with out a notch, cutout, or mechanical pop-up.

Telephones with these options exist already. In 2019, Meizu previewed a device that had tiny bezels, no seen sensors, no charging port, and no buttons. Quite, it relied on an under-display speaker for calls and haptic suggestions to re-create the feeling of bodily buttons. It additionally solely used wi-fi charging. Later that 12 months, Oppo introduced a phone with an under-display selfie digital camera.

We would see these seamless product designs enter extra mainstream gadgets. Samsung has introduced plans to combine under-display digital camera expertise in future gadgets. There are additionally rumors that Apple would possibly take away the iPhone’s charging port and go all-in on wi-fi charging. The MagSafe expertise will certainly assist with that.

In-display fingerprint scanning is like magic! You touch the screen, it reads your fingerprint, and then it instantly unlocks your phone. Let’s look at the technology behind the magic.

Moving Away from Physical Scanners

Fingerprint scanning, like other forms of biometric recognition, is nothing new to computing devices. While scanners have been on laptops for several decades now, the first mobile phone to have one was the Pantech GI100 in 2004. They came back in a big way during the smartphone era, though, due to the ever-growing need to protect the data in our pockets.

In 2013, the Apple iPhone 5S became the first major mobile device in the U.S. market to have a fingerprint scanner with the launch of Touch ID. Although Apple has since phased replaced this feature with facial recognition, fingerprint scanners became standard on all smartphones. Most placed the biometrics on the back or side of the device.

Over the last few years, other phone manufacturers have also phased out physical fingerprint scanners. Like Apple, some have removed fingerprint verification entirely, but others have replaced the physical pad with a scanner in the screen. This allows you to unlock your phone by placing your finger on a specific area of the phone’s display.

The In-Display Scanning Process

Generally, the scanning process is the same, whether it’s a physical or in-display design.

Usually, a specific part of the screen has a scanning area under it. When you place your finger over the scanner, it takes a snapshot of your finger’s pattern with a camera or other sensor. It then matches it to the biometric data on your phone. If it’s a match, your phone will instantly unlock.

One of the biggest problems in-display scanners is the scanning area is relatively small. It’s often a small box in the lower quarter of the display. Phone manufacturers often include a guide in the software to show you where to place your finger. This will appear when the screen is turned on or if your device supports always-on displays.

The scanning process can be instantaneous or very slow. This is likely due to the large differences between the two scanning technologies.

Optical vs. Ultrasonic

There are two primary types of in-display fingerprint scanners: optical and ultrasonic.

Optical scanners shine a bright light on your finger (it often appears on-screen as an animation). It then takes a picture of your illuminated fingerprint with a camera under the screen and makes sure it’s registered. If it is, the phone unlocks.

Many think the optical scanner is the less secure of the two technologies because it uses a simple camera to capture a fingerprint image. However, it’s often significantly faster. Depending on software optimization, it can be just as fast as even the best physical fingerprint scanner. You’ll find optical scanners on OnePlus phones and many midrange devices.

Ultrasonic scanners are typically regarded as the better of the two technologies. Instead of light, they use ultrasonic sound waves that bounce off your finger to capture an accurate 3D image. This technique is similar to that used in medical ultrasound machines.

Ultrasonic scanners are significantly more secure than opticals because it’s much tougher to fake a 3D image of a fingerprint. They’re also more stable than optical scanners and work in more challenging conditions, such as when your hands are wet or dirty. You’ll can find these mini ultrasounds in high-end devices, like Samsung’s Galaxy series.

The Future of Seamless Tech

In-display fingerprint scanners are part of a larger plan by smartphone manufacturers to minimize visible intrusions. These include buttons, cameras, sensors, speakers, ports, and unused bezel space.

Along with the rise of in-display scanners, companies have also begun adding pop-up, front-facing cameras to improve the display-to-body ratio. This coincides with the removal of headphone jacks, and companies competing to create true wireless earbuds for their phones.

In the future, more features might be migrated under the screen. Under-display speakers allow you to listen to calls and stereo audio without any visible speaker grills. There’s also an under-display camera that allows you to take portrait photos without a notch, cutout, or mechanical pop-up.

Phones with these features already exist. In 2019, Meizu previewed a device that had tiny bezels, no visible sensors, no charging port, and no buttons. Rather, it relied on an under-display speaker for calls and haptic feedback to re-create the sensation of physical buttons. It also exclusively used wireless charging. Later that year, Oppo introduced a phone with an under-display selfie camera.

We might see these seamless product designs enter more mainstream devices. Samsung has announced plans to integrate under-display camera technology in future devices. There are also rumors that Apple might remove the iPhone’s charging port and go all-in on wireless charging. The MagSafe technology will definitely help with that.

Fingerprint sensors are one of the most popular forms of biometric security when it comes to smartphones. Here’s everything you need to know about optical, capacitive, ultrasonic and in-display fingerprint sensors and how they work.

What kind of fingerprint sensor does my phone have?

Regardless of whether your phone’s fingerprint sensor is built into the display or the body of the device, it’s still inevitably going to fall into one of three implementation-based categories: optical, capacitive or ultrasonic.

How do optical fingerprint sensors work?

Optical fingerprint sensors are one of the more simple forms of biometric security out there. They rely on using an LED to illuminate your finger and then capturing that 2D image data using a sensor. Once it has captured that data, an optical fingerprint sensor can then compare subsequent image data against it to determine whether there is a match.

How does in-display fingerprint scanning workCredit: HTC

How do capacitive fingerprint sensors work?

Capacitive Fingerprint sensors are slightly more advanced. Rather than use light to map out the surface of your fingerprint, they use electricity. A regular capacitive fingerprint sensor relies on an array of capacitor plates to capture what any individual fingerprint looks like. Essentially – a capacitive sensor uses capacitors to map out the areas of your fingerprint which are more and less conductive. It then uses that as a basis for identifying subsequent samples.

Right now, capacitive fingerprint sensors are the most common form of fingerprint sensor in smartphones.

How do ultrasonic fingerprint sensors work?

Like the name suggests, ultrasonic fingerprint sensors use ultrasonic waves to map out a three-dimensional image of your fingerprint in the same that ultrasonic waves are used to in fields like medicine.

In theory, ultrasound presents several key advantages over the other fingerprint scanning technologies due to its ability to detect things like blood flow and also work more reliably in non-ideal conditions, for example if your hands are dirty or wet.

Which type of fingerprint sensor is the best?

I mean, for most everyday users, the best fingerprint sensor is going to be the one available to them. You shouldn’t choose one phone brand over another just because it has an ultrasonic fingerprint sensor. The end experience isn’t all that different, regardless of which fingerprint sensor technology you rely on.

That being said, if you’re asking which is the most versatile and secure, then ultrasonic is probably going to be the way to go. On paper, at least, it’s more reliable than the other options and the fact that it’s capturing a three dimensional fingerprint rather than a 2D one does suggest it would be more difficult to spoof.

How do in-screen fingerprint sensors work?

Currently, there are both optical and ultrasonic in-screen fingerprint sensors that can be found in modern smartphones.

In-display optical sensors work by capturing an image of your fingerprint based on the light reflected from the gaps between the pixels on your phone’s display.

In-display ultrasonic sensors work by projecting ultrasonic waves through the surface of the screen, since ultrasonic waves can travel through solid materials in a way that light can’t.

How secure are in-screen fingerprint sensors?

Any in-screen fingerprint sensor is only as secure as the component itself. There are several different in-display sensors on the market, some of which are optical and some of which are ultrasonic.

Qualcomm say their Sense ID ultrasonic in-display sensor has a 1% error rate.

Goodix’s in-display fingerprint sensor has a 0.002% false acceptance rate and a false rejection rate of less than 2%.

However, it’s worth remembering that – in consumer electronics especially – convenience often trumps security. As long as the sensor in question at least seem secure enough that they don’t have to think about it, most consumers are likely to opt for a faster and more reliable option over a more secure one.

How does in-display fingerprint scanning workCredit: Samsung

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How Does In-Display Fingerprint Scanning Work?

How does in-display fingerprint scanning work

In-display fingerprint scanning is like magic! You touch the screen, it reads your fingerprint, and then it instantly unlocks your phone. Let’s look at the technology behind the magic.

Moving Away from Physical Scanners

Fingerprint scanning, like other forms of biometric recognition, is nothing new to computing devices. While scanners have been on laptops for several decades now, the first mobile phone to have one was the Pantech GI100 in 2004. They came back in a big way during the smartphone era, though, due to the ever-growing need to protect the data in our pockets.

In 2013, the Apple iPhone 5S became the first major mobile device in the U.S. market to have a fingerprint scanner with the launch of Touch ID. Although Apple has since phased replaced this feature with facial recognition, fingerprint scanners became standard on all smartphones. Most placed the biometrics on the back or side of the device.

Over the last few years, other phone manufacturers have also phased out physical fingerprint scanners. Like Apple, some have removed fingerprint verification entirely, but others have replaced the physical pad with a scanner in the screen. This allows you to unlock your phone by placing your finger on a specific area of the phone’s display.

The In-Display Scanning Process

Generally, the scanning process is the same, whether it’s a physical or in-display design.

Usually, a specific part of the screen has a scanning area under it. When you place your finger over the scanner, it takes a snapshot of your finger’s pattern with a camera or other sensor. It then matches it to the biometric data on your phone. If it’s a match, your phone will instantly unlock.

One of the biggest problems in-display scanners is the scanning area is relatively small. It’s often a small box in the lower quarter of the display. Phone manufacturers often include a guide in the software to show you where to place your finger. This will appear when the screen is turned on or if your device supports always-on displays.

The scanning process can be instantaneous or very slow. This is likely due to the large differences between the two scanning technologies.

Optical vs. Ultrasonic

There are two primary types of in-display fingerprint scanners: optical and ultrasonic.

Optical scanners shine a bright light on your finger (it often appears on-screen as an animation). It then takes a picture of your illuminated fingerprint with a camera under the screen and makes sure it’s registered. If it is, the phone unlocks.

Many think the optical scanner is the less secure of the two technologies because it uses a simple camera to capture a fingerprint image. However, it’s often significantly faster. Depending on software optimization, it can be just as fast as even the best physical fingerprint scanner. You’ll find optical scanners on OnePlus phones and many midrange devices.

Ultrasonic scanners are typically regarded as the better of the two technologies. Instead of light, they use ultrasonic sound waves that bounce off your finger to capture an accurate 3D image. This technique is similar to that used in medical ultrasound machines.

Ultrasonic scanners are significantly more secure than opticals because it’s much tougher to fake a 3D image of a fingerprint. They’re also more stable than optical scanners and work in more challenging conditions, such as when your hands are wet or dirty. You’ll can find these mini ultrasounds in high-end devices, like Samsung’s Galaxy series.

The Future of Seamless Tech

In-display fingerprint scanners are part of a larger plan by smartphone manufacturers to minimize visible intrusions. These include buttons, cameras, sensors, speakers, ports, and unused bezel space.

Along with the rise of in-display scanners, companies have also begun adding pop-up, front-facing cameras to improve the display-to-body ratio. This coincides with the removal of headphone jacks, and companies competing to create true wireless earbuds for their phones.

In the future, more features might be migrated under the screen. Under-display speakers allow you to listen to calls and stereo audio without any visible speaker grills. There’s also an under-display camera that allows you to take portrait photos without a notch, cutout, or mechanical pop-up.

Phones with these features already exist. In 2019, Meizu previewed a device that had tiny bezels, no visible sensors, no charging port, and no buttons. Rather, it relied on an under-display speaker for calls and haptic feedback to re-create the sensation of physical buttons. It also exclusively used wireless charging. Later that year, Oppo introduced a phone with an under-display selfie camera.

We might see these seamless product designs enter more mainstream devices. Samsung has announced plans to integrate under-display camera technology in future devices. There are also rumors that Apple might remove the iPhone’s charging port and go all-in on wireless charging. The MagSafe technology will definitely help with that.

How does in-display fingerprint scanning work

– The tech behind under-display fingerprint readers

(Pocket-lint) – An increasing number of phones feature an in-display fingerprint reader. But how do they work and how is the tech evolving?

Although the iPhone has moved to Face ID on new models, all of the big Android phones offer fingerprint ID as the main biometric entry point to your phone – even if they also hedge their bets in terms of supporting improved facial recognition as well.

Huawei and Oppo/OnePlus were first to seriously incorporate fingerprint sensors under the screen and they remain some of the key advocates. Let’s look at the technologies involved in bringing under-display fingerprint readers to our phones.

Optical vs ultrasonic

Most of the scanners we’ve seen so far are optical scanners – these use some light to illuminate your finger. A tiny camera under the screen takes an image of your finger which is then compared to the stored image.

We had thought under-display fingerprint scanners will increasingly also be ultrasonic instead of optical and it’s one of these that is used inside the Galaxy S10 series. But the lack of takeup of these sensors does rather point toward the fact they’re too expensive to use.

Ultrasonic sensors work using ultrasound to build up an image of your fingerprint (yes, really) and work better with messy fingerprints – if your hands are wet or oily with sun cream, for example. They’re essentially ‘Face ID for your finger’.

How does in-display fingerprint scanning work

Qualcomm announced the third-generation version of its existing ultrasonic scanner – 3D Sonic – at its annual Tech Summit in late 2018. And it’s just revealed another generation on from that, called 3D Sonic Max (yes, another company using the well-trodden ‘Max’ suffix).

Alex Katouzian, head of mobile at Qualcomm, announced on stage that 3D Sonic Max offers a 17x larger recognition area than the previous generation, meaning there can be simultaneous two-finger authentication for increased security as well as being easier to use because you don’t need to be so precise on placement. Yes, you read that right – some phones will enable you to restrict access with dual fingerprints.

The tech is the latest version of Snapdragon Sense ID which was originally shown off in 2015. Here’s the 3D Sonic Max sensor:

How does in-display fingerprint scanning work

Is ultrasonic better?

On the surface of it, the answer is yes. But it won’t matter if more handsets don’t take them up becuase of the extra cost.

The road to ultrasonic fingerprint readers has been reasonably long. In 2013 Qualcomm acquired a company called Ultra-Scan, a small company with “very good IP for ultrasonic waveform” and with a background in producing ultrasonic readers for the US Government.

“We took that and found a way to manufacture in the millions to keep the costs down,” explained Qualcomm’s Katouzian. “We don’t need to shine a light source through the display. The light source over time can degrade the LCD. it’s very similar to a photocopier.

Qualcomm certainly isn’t the only name in fingerprint sensors though; Synaptics is another while Goodix also makes sensors for a huge number of Android devices including under-display sensors from Huawei, Vivo, Oppo, OnePlus and Xiaomi. Its tech can work under both LCD and OLED displays.

Indeed, there are around 100 devices currently using Goodix tech in their readers.

Synaptics is a company that’s been involved in computing and phone interfaces for more than 30 years; it developed the first computer touchpad and the touch tech for the click wheel on the iPod. Its tech is also used for many standard external fingerprint sensors on phones (such as those on buttons).

Wider zone optical sensors

We’re expecting plenty more phones to launch with optical sensors – the tech certainly isn’t going away. In early January Oppo showcased a “wide zone” optical fingerprint sensor, which recognises an area up to 15 times bigger than current sensors.

How does in-display fingerprint scanning work

That changes the game for optical since you can unlock or pay by being much less precise with your finger – and so use the phone one-handed.

Could we see this tech launch on a handset soon?

How does in-display fingerprint scanning work

After a few years lurking in backroom prototypes and inside a few quickly forgotten handsets, ultrasonic fingerprint sensors are ready for prime time. The technology is built into Samsung’s flagship Galaxy S10 and Galaxy S10 Plus, making the technology almost guaranteed to be securing millions of thumbprints by the year’s end.

In December 2018, Qualcomm announced its 3D ultrasonic in-display fingerprint sensor. This technology is enabled in devices using the company’s Snapdragon 855 platform as an option if the manufacturer wants to include the extra hardware. Ultrasonic fingerprint technology has its own pros and cons versus traditional capacitive scanners and even other in-display fingerprint designs. Here’s everything you need to know.

How ultrasonic fingerprint scanners work

Qualcomm’s 3D in-display ultrasonic fingerprint scanner is based on what used to be called Sense ID. Rather than existing photographic or capacitive-based fingerprint scanners, ultrasonic fingerprint scanners make use of very high-frequency ultrasonic sound. You can’t hear it, but these waves are used to map out the details of the user’s fingerprint. Fortunately, there’s no need to swipe, just touch the finger to the sensor like the top of the line capacitive fingerprint scanners.

How does in-display fingerprint scanning work

How fingerprint scanners work: optical, capacitive, and ultrasonic variants explained

To actually capture the details of a fingerprint, the hardware consists of both a transmitter and a receiver. An ultrasonic pulse is transmitted against the finger that is placed over the scanner. Some of this pulse’s pressure is absorbed and some of it is bounced back to the sensor, depending upon the ridges, pores and other details that are unique to each fingerprint.

There isn’t a microphone listening out for these returning signals. Instead, a sensor that can detect mechanical stress is used to calculate the intensity of the returning ultrasonic pulse at different points on the scanner. Scanning for longer periods of time allows for additional depth data to be captured, resulting in a highly detailed 3D reproduction of the scanned fingerprint.

Qualcomm notes that there’s about a 250-millisecond latency for unlocking, roughly equivalent to capacitive fingerprint scanners. The sensor has about a 1 percent error rate, which again is pretty comparable to other scanners.

Pros of ultrasonic fingerprint vs capacitive scanners

Ultrasonic fingerprint technology works very differently to capacitive fingerprint scanners, which are only able to reproduce 2D images. 3D details are much more difficult to forge or fool than a 2D image, making the ultrasonic system much more secure. It goes without saying that ultrasound is also much more secure than optical fingerprint scanners, which have all but fallen out of favor.

In-display scanners like those inside the OnePlus 6T and Huawei Mate 20 Pro are optical not ultrasonic.

Another added perk of this ultrasonic fingerprint scanner technology is that it allows the fingerprint scanner to still operate through thin materials, such as glass, aluminum, or plastic. The sensor is just 0.15 millimeters thick and can scan through up to 800 µm of glass and up to 650 µm of aluminum. Therefore, the scanner can be embedded under the case or under the display as we’re seeing in the Samsung Galaxy S10, allowing for a more discrete look and thinner bezels.

Because the sensor uses ultrasonic waves, the sensor can also double up as a health tracker that can record heart rate and blood flow. Additionally, there’s less chance of damaging the sensor or exposing it to external tampering, and sweat or moisture on the finger won’t interfere with the scanning process either.

Scanning is just half the process

How does in-display fingerprint scanning work

The best phones with in-display fingerprint scanners (October 2020)

Of course, there’s still plenty to be done with this fingerprint data and keeping it secure is an equally important part of the system.

As will all biometric security systems, processing and security highly sensitive personal information security are key. Qualcomm’s processors are built with dedicated security tools, including Cryptographic Accelerators, Key Provisioning Security, and a Trusted Execution Environment. This ensures that the processing and storage of sensitive data are kept well away from malicious applications. Other Arm-based processors offer TrustZone hardware isolation for similar levels of protection.

Qualcomm’s setup is also designed to support the Fast Identity Online (FIDO) Alliance protocols, which can be used for online password-less authentication. FIDO does this without transferring any of the confidential fingerprint information to the cloud or through networks that could be compromised.

Ultrasonic fingerprint scanners certainly have a number of advantages of existing capacitive implementations and given the prevalence of Qualcomm processors in mobile products. 3D ultrasonic fingerprint scanners are now ready for prime time and it’s possible that we’ll see many more manufacturers adopt this technology throughout 2019.

How does in-display fingerprint scanning work

Since fingerprint scanners first appeared on smartphones in 2011 they’ve become pretty much a standard feature. They’re fast, convenient, and relatively secure, since fingerprints are unique enough that the odds of anyone having a similar enough print to unlock your phone are very low, unless someone cares enough to design a convincing duplicate of your fingerprint.

There’s not just one type, though: some scanners rely on light, others on electricity, and still others on sound to map the ridges and valleys of your fingers. Capacitive (electronic sensors) are popular in smartphones because they’re accurate, small, and fast, but optical and ultrasonic technologies have the advantage of enabling in-display scanning. But what’s actually going on in those milliseconds right after you put your finger on a scanner?

How does in-display fingerprint scanning work

Optical fingerprint scanners

How does in-display fingerprint scanning work

The most basic type of fingerprint scanner works along the same lines as a digital camera. To oversimplify the process a bit, it just takes a picture of your finger and sends that picture off for processing. The following is the general idea:

  1. The scanner shines a bright light onto your finger using LEDs and takes a picture.
  2. If the average pixel value of the photo is too dark or light, it adjusts the exposure and tries again.
  3. It also checks for good resolution by seeing if dark and light areas are alternating in a way that’s consistent with clearly-defined ridges and valleys.
  4. If the picture is clear, the image can be processed!

This type of scanner is most common in places like police stations, airports, and secured entrances, but isn’t often used in smartphones, which favor smaller, more secure capacitive sensors.

The exception is smartphones that have in-display fingerprint scanners, some of which use optical or ultrasonic sensors under the screen to get an image. Even here, though, optical sensors tend to lose out to ultrasonic scanners, which are slower but have the advantage of not being vulnerable to 2D images of fingerprints.

Capacitive fingerprint scanners

How does in-display fingerprint scanning work

When you put your finger on a capacitive scanner, it’s using tiny amounts of electricity to measure the distance between different parts of your finger and the scanner. Inside the scanner are rows of tiny capacitors, each of which can carry an electrical charge. If one of the capacitors is below one of your fingertip’s ridges, it can hold more charge since it’s coming into contact with your skin. If it’s below a valley, the capacitor will remain in contact with air, which doesn’t allow it to store much extra charge.

How does in-display fingerprint scanning work

You can somewhat think of these capacitors as pixels in a camera. If one is holding more of a charge, that can be interpreted as a ridge area, while the others are read as valleys. Taken as a whole, this gets you an image of a fingerprint that’s just as accurate as one from an optical sensor and even more secure, since tricking it would require a 3D model of the fingerprint rather than just a 2D one. This, combined with its smaller size, makes it a popular choice among smartphone manufacturers.

Ultrasonic fingerprint scanners

How does in-display fingerprint scanning work

If you can read fingerprints with light and electricity, why not sound? Ultrasonic scanners fire out a high-frequency pulse of sound that then bounces off the user’s fingertip back to the receiver, a sensor that can measure mechanical stress. That sensor is looking at the intensity of the returning pulse at different points on the finger and can use that data to calculate where the ridges and valleys are. It’s a little bit like the way a bat navigates by making high-pitched noises and listening to the echoes – the returning sound carries some important data about distance and size.

Because sound waves can measure the depth of the valleys in a fingerprint, the resulting map is 3D, which makes ultrasonic scanners even more precise and secure (if a bit slower) than capacitive models. They can also work as under-display fingerprint scanners, as the sound waves can easily travel through glass, making them a more secure alternative to optical versions.

Analyzing, storing, and using the fingerprint

How does in-display fingerprint scanning work

After the image is captured, whether through light, electricity, or sound, the software needs to check if the fingerprint matches with an authorized user. Figuring out fingerprint matches, whether you’re a human or a computer, is largely done by looking for things called “minutiae” – points of the fingerprint where something relatively interesting happens, like a place where ridgelines terminate or split.

Each of these features is assigned a position relative to the other detected minutiae, and using the distance and angle between each item, the scanner software can make sort of a map that can be represented as a number. That number is essentially the encoded fingerprint.

Any data that your phone stores about your fingerprint, even if it’s just the maps of minutiae, is generally locked away in a secure environment, isolated from other apps that might try to get access to that information. Any apps or websites you use your fingerprint to access won’t ever actually receive your fingerprint data. They’ll only get a confirmation from your device that the fingerprint that was scanned matches one of those in storage.

Are fingerprint scanners secure?

Fingerprint scanners aren’t the most foolproof way to control access to something since they can often be tricked by good models, anything from a 2D picture to a 3D prosthetic. They are improving, and the security protocols for handling fingerprint data are fairly strong (as long as they’re being followed), but if you’re really worried about someone getting physical access to your phone, fingerprints aren’t the strongest lock. As ultrasonic sensors improve, though, they’ll probably get faster and more secure, and having them embedded under the display is a very neat perk.

Andrew Braun is a lifelong tech enthusiast with a wide range of interests, including travel, economics, math, data analysis, fitness, and more. He is an advocate of cryptocurrencies and other decentralized technologies, and hopes to see new generations of innovation continue to outdo each other.

How does in-display fingerprint scanning work

Apple’s iPhone 5s started the whole smartphone biometrics saga with the introduction of Touch ID. The fingerprint scanner element is now ubiquitous, embedded in home buttons, mounted on the back side of mobile phones and even placed on the side beneath the home button of handsets. Naturally, the development of faster and more accurate fingerprint readers led to the makings of newer ways of unlocking your smartphone.

This includes facial recognition like Face ID and something that we will be discussing in detail today; the in-screen fingerprint reader. As we see more high screen-to-body ratio smartphones getting released, a consequence of this action is the where to put the fingerprint reader, which is often moved to the back of the phone to compensate for those ‘all screen’ handsets.

However, having an in-screen fingerprint reader will forego this change and we will explain what its internals are like and what are the possibilities for the future of smartphones.

Synaptics Hard at Work With Its Clear ID FS9500 Intended for High-End Smartphones

Synaptics and Vivo have this long-term partnership that enabled the making of the Clear ID FS9500, which is an optical sensor that can be placed beneath the display of the smartphone. In short, it is an optical sensor, or a CMOS sensor, the kind that you find in regular or smartphone cameras. In order for it to work, there are going to have to be some requirements.

How does in-display fingerprint scanning work

The display on the smartphone needs to be an OLED panel, which is why you are only going to find it on devices that are touting OLED screens and that can only mean that for now, high-end phones will come bearing this security addition. Goodix is also working to bring in-display fingerprint scanners to manufacturers so more suppliers also mean that companies will be able to negotiate better pricing for this component.

How Does the in-Screen Fingerprint Reader Work?

When you hold up the phone, the fingerprint sensor indicator will light up, meaning that you can now unlock your smartphone using this part of the biometrics. According to videos seen online, it is definitely slower than regular fingerprint readers so improved iterations of the scanner will have to be introduced to make it faster. This is possibly the reason why Samsung might have refused to incorporate this sensor on the Galaxy S9 and Galaxy S9 Plus.

How does in-display fingerprint scanning work

As thin as it might be to fit inside the display, it is quite slow, and though it is present at an ‘easy to reach’ location, users will definitely complain about the speed problems. Coming back to unlocking the device, after you have placed your fingerprint on the scanner, a light will shine on the sensor to capture your fingerprint and unlock the smartphone. However, this is just the beginning of such sensors because it does not have to be located in a single region on the phone.

What Are the Possibilities of the in-Display Fingerprint Scanner for Future Smartphones?

As we said before, the sensor does not have to be placed at a single location. During the announcement of the Vivo APEX, which is honestly the first glimpse into the future of what bezel-less smartphones will look like, it too features an in-glass fingerprint reader, but here’s the catch.

The bottom half of the phone is covered by this CMOS sensor, which the company is calling it the ‘Half-Screen Fingerprint Scanning Technology’. This means that you place your finger anywhere at the bottom half and if your fingerprint is registered, the phone will unlock seamlessly.

How does in-display fingerprint scanning work

This development also means that there is a future where we might get to see smartphones with their entire displays being covered with the sensor.

All you will have to do is whip it out, place your finger anywhere and immediately, the phone will be unlocked. That is certainly a future that we will look forward to witnessing but for that specific future to materialize and become a reality, better versions of the fingerprint are going to have to be released.

How does in-display fingerprint scanning work

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