Are you curious on how fingerprint scanners exist on smartphones? You’re not alone. Fingerprinting authentication is widely used and is one of the most reliable biometric technologies, with more than 85% of the smartphones across the globe using it in 2024.
Biometric technology which focuses on the use of fingerprints has revolutionized mobile security in terms of speed, security, and privacy. This technology is used from sim cards to making payments: a necessity in today’s society.
Due to the development of the sensors and artificial intelligence, the fingerprint recognition in smartphones is 99% accurate. But how does it really operate? In other words, let me simplify it for you as follows.
It is important for users and technology aficionados to know how the technology behind fingerprint scanners on smartphones works. Here is all you need to know.
How Fingerprint Scanners Work on Smartphones
This is a method of using an optical scanner that captures a clear image or pattern of a user’s fingerprint and compares it with the biometric details saved in the phone.
When you touch your finger on the sensor, it maps the ridges and the furrows on your fingertip. The scanner then transforms this image into a digital form of data that is referred to as a biometric template. If the key entered matches the one stored in the database, then the system grants access.
Smartphones utilize one of the three types of sensors namely optical, capacitive or ultrasonic to perform this scan. It is connected to a secure processing unit so that data is not stored in the form of an image.
It happens in a matter of milliseconds and can be used for such purposes as unlocking the phone, logging into applications or verifying payments. In particular, it is fast and secure because no two fingers are alike even if the individuals are identical twins.
The Science Behind Fingerprint Recognition Technology
Fingerprint recognition is based on the field of biometrics, which is the field of science that is used to validate identity.
Fingerprint recognition is based on pattern matching algorithms and the biometric identification system. Fingerprint patterns include ridges, their terminations, bifurcations and arches and they are unique to each person and remain constant over the lifespan of a person.
This pattern is then recorded by the scanner as it is not an image but rather a mathematical formation and then the formation is saved securely. Every time, this new pattern is compared with the encrypted biometric template matching using the AI algorithm.
Capacitive and ultrasonic scanners employ electrical conductivity or sound waves to get 3D fingerprint features while optical scanners use light surface patterns.
It also uses machine learning for enhanced recognition and this makes the device recognize the skin even if it has changed slightly, say, if one develops dry skin or has a minor injury.
Types of Fingerprint Sensor Technologies
Three types of fingerprint sensors that are commonly used in smartphones include the optical, capacitive, and ultrasonic sensors. Of the two, each differs in how it analyzes, stores, and protects fingerprint information.
1. Optical Fingerprint Sensors
How it works: Optical sensors employ the use of a light source, usually LEDs to capture an image of the fingerprint. It shines a red light on the skin of your finger and captures the map of the ridges and valleys.
Present in: High-end and the latest generation mobile devices.
2. Capacitive Fingerprint Sensors
How it works: This technology involves the use of little circuits of capacitors to identify the fingerprint patterns. It is not a visible image; it scans the electrical variations resulting from the configuration of the ridges of the finger.
Present in: Most of the mid-tier and high-end smartphones that incorporate rear or side-mounted sensors.
3. Ultrasonic Fingerprint Sensors
Ultrasonic scanners: These work by emitting sound waves of high frequency in order to create a three-dimensional map of your fingerprint. It reflects back at different speeds depending on the ridge and pore structures to get the depth image of the finger.
Present in: Some mid-range to high-end smartphones with in-display sensors (e.g., Samsung Galaxy S21 Ultra, OnePlus 11).
The Security Benefits of Fingerprint Authentication
With the help of fingerprint identification, the security level of the smartphone is increased significantly as it offers fast, accurate, and personal access which is difficult to fake or steal.
While passwords, PINs or codes can be easily forgotten, shared, or cracked, fingerprints are biometric and hence do not change with time. This makes the use of fingerprint authentication as a very secure and efficient method of guarding personal information on the devices.
Key Security Advantages:
- Inalienable and Irreversible: Fingerprint remains the same for a person throughout the lifetime and can’t be changed. This makes it unique and greatly minimizes the chances of unauthorized access.
- Local Data Storage: Biometric data is stored locally on the device in the Trusted Execution Environment (TEE) and not on the cloud and therefore safe even if the phone is hacked.
- Quick and discreet: Scanning does not take more than a second and the data stripped includes any passwords or e-mail addresses.
- Enhances App and Mobile Banking Security: Biometric verification codes such as fingerprints can be used together with a password or a pattern for better security on apps, mobile banking or digital wallets.
- Spoof-Resistant (Advanced Sensors): Some of the sensors include Ultrasonic and capacitive sensors that can capture the live skin and 3D features of fingers hence making it difficult for spoofing.
Fingerprint Sensor Placement on Smartphone Devices
The position of the fingerprint sensors in the Smartphone has expanded through time based on the design factors and the convenience of the users. Today, there are four basic placement options and each of them has its strengths and weaknesses according to the criteria such as accessibility, aesthetics, and functionality.
Older smartphones had their fingerprint scanners located at the backside of it and they were often placed underneath the camera. This location is suitable when holding the phone because the index finger stays here naturally. However, it is somewhat impractical when the device is placed on a flat surface.
In an effort to enhance usability, most manufacturers slowly started using side mounted sensors, which are usually placed in the power key. These are especially popular in slim, modern designs especially the more slim and sleek dresses that are current in fashion today. Integrated side-mounted scanners are also very convenient as they may be accessed easily with no need to put down your phone, and many people unlock it as soon as they take it in their hand.
Gradually, new trends came up with bezel-less displays, and the focus changed to under-display fingerprint scanners. This placement provides a neat and clean appearance due to its integration under the screen. It is widely available in most contemporary flagship and upper mid-range devices and runs on optical or ultrasonic systems. While the first-generation products were very particular about where the tags were to be placed, some of the latest models are much faster affording one more leeway while placing them.
Some of the old generation and some of the latest generation devices with classic design have front-mounted sensors, which are most often located in the Home button. This position is convenient when the phone is placed on a desk, but it is not common now because of the introduction of full-screen designs.
Final Word
The knowledge of how fingerprint scanners work (smartphone) gives one a sense of science and security when using the gadgets in day to day life. Fingerprint recognition still remains a fast, secure and easy way to safeguard your own information on the phone as technology advances.
