Xiaomi has patented a new full-screen fingerprint recognition solution. The solution is being pitched as the next evolution of in-display fingerprint recognition, which has become increasingly ubiquitous in consumer devices in the past few years.
Phones that support in-display fingerprint recognition allow users to unlock their devices with a fingerprint sensor that has been placed below the screen. Such sensors do not take up any real estate on the surface of the phone, but users do need to place their fingers directly over the sensor in order to generate a positive match. In that regard, such sensors have many of the same limitations as more traditional fingerprint scanners.
The technology in Xiaomi’s patent is designed to fix that problem, which is to say that it would allow people to place their finger anywhere on the screen when they unlock their phone. In practice, the feat is accomplished with an array of infrared LED light transmitters that is placed in between the AMOLED display and the capacitive touch layer of the screen. The LED transmitters will activate whenever someone presses their fingertip onto the capacitive layer.
The system will only activate the transmitters in the area covered by the fingertip. The infrared light will shoot up through the screen and then bounce back, where it will be picked up by an array of infrared light receivers. The phone will use that light data to map the person’s fingerprint, and unlock if that new data matches the fingerprint data already registered to the device.
The infrared light receivers will be placed above the infrared light transmitters. While the transmitters below the fingertip will light up, the transmitters in the rest of the screen will not activate at all during the scan.
Xiaomi is expected to deploy the new technology across its entire smartphone portfolio. The company’s new patent was granted in China. Huawei also tried to patent its own full-screen fingerprint recognition system in several countries back in 2020.