Fingerprint Sensors

Smartphones industry is one of the most competitive industries in the world. That’s why every year, smartphone companies have to come up with new features to attract buyers to new smartphones. The advantage of this fierce competition between smartphone manufacturers is that every year we see the wide collection of improved smartphones with many unique features. In the last decade, smartphone manufactures has come up with different ways to unlock our smartphones. From a simple PIN method to the advanced facial recognition, we have seen all. Now the companies are working on the in-display fingerprint sensors which they think can be a great way to unlock your smartphone. In this comprehensive guide, we will tell you everything you need to know about the in-display fingerprint sensors. Let’s get into it.

Brief History of Fingerprint Sensors

The concept of using the fingerprint sensors in the phones is not new. The first phone with the fingerprint sensor was launched back in 2004. It was launched by the South Korean company known as Pantech and the phone was called the “Pantech GI100”. Later on, the Japanese company Toshiba launched the G900 and G500 phones and both devices were equipped with fingerprint sensors.

Later on, other smartphone giants such as HTC, Motorola, and Acer also started using the fingerprint sensors in their smartphones. Apple also joined the party in 2013 when they included the fingerprint sensor in their iPhone 5s.

The concept of in-display fingerprint sensors was introduced during the MWC 2018 when the Vivo, the Chinese smartphone company, came up with the concept device named Vivo Apex. The device was featuring the optical fingerprint sensor which was developed by the US-based company known as Synaptics. After a few months, Vivo launched this device for the consumers with the name “Vivo X20 Plus UD”. Since then many tech giants such as OPOO, Samsung, Huawei, RealMe and Xiaomi have introduced this technology in their smartphones.

What is the in-display fingerprint sensor?

If you don’t know much about the in-display fingerprint sensors then this section will help you know them better. The normal fingerprint sensors in the smartphones which we usually find on the back or the side of the phones are the capacitive fingerprint sensors. They read our fingerprints when we place our fingers on them.

In-Display fingerprint sensors are the ones that are placed under the display. When you place your finger on the display, the in-display fingerprint sensor reads the fingerprint and then verifies if the true owner of the phone is accessing the smartphone.

Types of In-display Fingerprint Sensors

When it comes to In-display fingerprint sensors, there are two types of In-display fingerprint sensors available out there.

  • Optical In-display fingerprint sensors
  • Ultrasonic In-display fingerprint sensors

Optical In-display fingerprint sensors

Optical in-display fingerprint sensors are the earliest form of in-display fingerprint sensors. In General, optical sensors have been around for a long time but the optical in-display fingerprint sensors are new to the smartphones.

In this technology, the optical in-display sensor takes the image of your finger and then compares it with the stored image. For this purpose, we have the “Charge-Coupled Device (CCD)” in the optical sensor which is also used in modern digital cameras.  CCD is the array of light-sensitive diodes known as photosites. The photosites respond to the light protons by generating the electrical signals.

When you place your finger on the sensor, the LEDs light up your fingerprint and CCD quickly captures the image of your Fingerprint. Then the CCD passes on this 2D image to the system where the system analyzes the print to know if the authorized person is accessing the smartphone or not.

Ultrasonic In-display fingerprint sensors

Ultrasonic In-display fingerprint sensors are the ones that use the ultrasonic sound waves to generate the model of your fingerprint. This technology is developed by Qualcomm and the first ultrasonic in-display fingerprint sensor came in the Galaxy S10 series.

Ultrasonic in-display fingerprint sensor technology is very accurate and it can read the fingerprints even through the containments such as oil, sweat, lotion, etc. Moreover, it provides the 3D print of the fingerprint which is more secure than the 2D scan in optical sensors.

The ultrasonic in-display fingerprint sensor requires the ultrasonic transmitter and receiver for its working. When you place your finger on the ultrasonic in-display fingerprint sensors, the transmitter launch the ultrasonic pulse which collides with your finger and then it bounces back which is captured by the receiver. The sensor is also capable of detecting mechanical stress which ultimately helps it to calculate the intensity of the bounce of ultrasonic pulse at different points. Once collecting all the information, the sensors create the 3D replica of the fingerprint and then match it with the stored fingerprint in the device.

Optical vs Ultrasonic In-Display Fingerprint sensor? Which one is better?

Optical and Ultrasonic in-display fingerprint sensors are still new technologies and both have a long way to go. When it comes to Optical In-Display fingerprint sensors, they are not very accurate as they only do the 2D scanning of the finger.

On the other hand, Ultrasonic In-Display fingerprint sensors are more accurate as they create the 3D replica of your finger. Hence, Ultrasonic In-Display fingerprint sensors are better in terms of accuracy and security.

However, Ultrasonic In-Display fingerprint sensors also have some limitations. For example, the ultrasonic waves have to pass through the display of the smartphone to reach your finger and then come back through the display to the receiver. If you install the thick screen protector on the display then it can affect the functionality of the In-Display fingerprint sensors. That’s the reason why the companies advise the users not to add the extra protection on their smartphones to allow the In-Display fingerprint sensor to work properly.

Bottom line

The In-Display fingerprint technology is still new and we believe that it will get better with time. Currently, you can find this technology in the premium and upper mid-tier smartphones but you can expect this technology in the budget smartphones in the next few years. If you have any questions, please let us know in the comment section below. Also, visit our website for more useful guides.