Laser arrays bring facial recognition to Androids

The Mi8 Explorer Edition, the new smartphone from Xiaomi, includes a face recognition system which uses infrared (IR) vertical cavity surface-emitting laser (VCSEL) arrays from ams. The PMSIL is a complete VCSEL flood illuminator system with integrated eye safety interlock, offering very high optical efficiency and minimising the drain on the phone’s battery when emitting.

The PMSIL incorporates the emitter die, and a diffuser in its compact 3x3x1mm package. It features high spectral stability over temperature, and a narrow spectral width of less than 1nm. Its engineered beam profile can be configured to the needs of specific smartphone applications.

In the Mi8 Explorer Edition, the PMSIL operates in always on mode for face detection and recognition. The IR VCSEL emitter in the structured lighting system, the CS115, is also supplied by ams. The IR emitter is an IR chip-on-substrate VCSEL array, and is also notable for its small footprint and high optical efficiency.

ams’ VCSEL technology is the result of 15 years of development which has resulted in numerous optimisations of the VCSEL fabrication process technology, materials and packaging. Customers can also draw on validated test data and performance models, providing predictable performance characterisations and accurate quality and reliability data.

The ams relationship with Xiaomi extends beyond the provision of IR laser arrays: ams also supplies the TMD27253 ambient light sensor and proximity detection module in the Mi8 and Mi8SE models.

Hui Nie, General Manager for product line VCSEL at ams, stated: “Xiaomi is a stand out performer in the Chinese smartphone market and, increasingly, globally because of its bold and innovative design approach and its ability to implement advanced technologies in beautiful, sleek phones. To fit the slim, bezel-less design of the Mi8 Explorer Edition, Xiaomi’s designers wanted to build the smallest possible face recognition system which led them to evaluate the ams IR VCSEL arrays. Once they tested the power consumption of the ams devices against that of competing products, the overall superiority of the ams parts became very clear.”