Today the U.S. Patent and Trademark Office officially granted Apple a patent that relates to single-photon avalanche diode (SPAD)-based photon detectors, such as SPAD-based depth sensors or three-dimensional (3D) image sensors. More particularly, the described embodiments relate to time-to-digital converters (TDCs) and histogram generation for SPAD-based photon detectors. Apple's granted patent links this patent to a Face ID technology update.
Apple's patent FIG. 1A presents an example of a device that may include an image sensor or depth sensor; FIG. 2 shows an example of a SPAD-based photon detector based on dot-projection; FIG. 3 shows another example of a SPAD-based photon detector, this time using a line-scan system.
To dive deeper into this technical patent review Apple's granted patent US 11476372 B1.
Apple originally filed for this patent in 2020, three years after Face ID was introduced on iPhone X. Apple acquired the foundation for Face ID technology from the Israeli company PrimeSense that Apple acquired in 2013.