In other words, Apple's selection of 3D facial recognition in the XS, XS Max and XR models of iPhone provides both a direct and indirect boost to manufacturers of light sensors. The annual market is expected to exceed $1.5 billion by 2022.
This iPhone effect is also likely to spell the beginning of the end for the fingerprint sensor market. IHS Markit forecasts the use of light sensors will effectively kill off the requirement for more than 900 million fingerprint sensors by 2021.
Light sensor revenue by application field in dollar-millions. Light-green = industrial, blue = automotive, grey = consumer electronics, dark-green = wireless communications. Source: IHS Markit.
Two different and competing approaches are currently used for facial recognition: structured light (SL) and time-of-flight (ToF) sensing.
SL provides greater accuracy in detection, delivers higher resolution, and utilizes less power. However, it requires several components, including a dedicated vertical-cavity surface-emitting laser (VCSEL) and a dot projector, as well as a near-infrared camera and carefully assembly along with computational resources.
ToF makes use of so-called single-photon avalanche diode (SPAD) receivers that can work with any target material and color, although a higher target illumination is required to obtain good accuracy.
Apple is using a mix of both approaches. By adding a near-infrared illuminator and enhance performance under most light conditions, albeit at extra complexity and cost. Other mobile handset manufacturers, such as Samsung, Huawei, Oppo, Vivo, and Xiaomi, are rumored to be working on Face-ID-like systems, albeit through a variety of approaches.