Today the U.S. Patent Office published a patent application of Apple's that relates to a next-generation projector that could be used for depth mapping in Face ID and other applications and used in a wide variety of devices such as an iPhone, iPad, AR devices, Smartglasses, Apple Watch and more. The new spot projectors are designed to project a dense, superior well-defined pattern of spots than today's projectors used with Face ID while maintaining a thin overall profile.

Steerable Projector Of Patterned Illumination

Apple notes that some depth mapping systems project a pattern of spots onto a target scene that is to be mapped like is used in Face ID. In some of these systems, the pattern is created by a laser or an array of lasers, such as vertical-cavity surface-emitting lasers (VCSELs). This approach is advantageous in creating intense, well-defined spots, as well as in generating short pulses when needed for measuring times of flight. The spatial resolution of the pattern is limited by the number of spots that are projected onto the target scene, which may in turn be limited by optical and electrical power constraints.

Typically, semiconductor-based optical emitters, such as VCSELs, emit beams with large angles of divergence. To form a well-defined pattern on the target scene, a projection lens collimates the beams. When a refractive lens (typically a compound lens) is used for this purpose, and the pattern projector is to be incorporated into a portable electronic device, the total track length of the lens may be a limiting factor in reducing the overall thickness of the device.

Embodiments of Apple's present invention provide spot projectors that address both these problems: They project a dense, well-defined pattern of spots while maintaining a thin overall profile.

These objects are achieved by using an optical metasurface to collimate the beams from an array of emitters and project a dense pattern of spots with a narrow angular divergence. To reach the desired pattern density with a limited number of emitters in the array, the angular width of the pattern projected by the optical metasurface may cover only a part of the target scene.

To compensate for the narrow angular width of the pattern, an active diffraction grating steers this pattern of spots over the target scene, and thus projects the pattern onto a particular area of interest and/or sweeps the pattern sequentially over the entire scene.

The optical metasurface can advantageously be formed on an optical substrate of the active diffraction grating, rather than as a separate element, so that the total track length of the optics is limited only by the thickness of the active diffraction grating itself. For example, the active diffraction grating may comprise a liquid crystal, with an optical metasurface formed on the transparent envelope of the liquid crystal.

Apple's patent figures cover an optoelectronic apparatus, comprising an array of emitters, such as VCSELs, which emit respective beams of optical radiation.

A steering module is mounted to intercept the emitted beams. The steering module comprises an active diffraction grating, which is fixed to an optical substrate and has a pitch that varies in response to an electrical signal applied to the active diffraction grating. The active diffraction grating deflects the beams of optical radiation by a variable angle, which depends on the pitch.

An optical metasurface, which is disposed on the optical substrate, collimates the beams of optical radiation to form a pattern of spots on a target scene. A controller varies the electrical signal applied to the active diffractive grating so as to shift the pattern of spots across the target scene.

Patterns of spots that are projected in this manner can be used in various applications, such as range measurement and 3D mapping. In some embodiments, the emitters output pulsed beams of optical radiation, and a receiver receives and measures the time of flight of the pulses reflected from the target scene. 

For full details, review Apple's patent application 20250044662.