For years Apple was purposely blocked in bringing a periscope-type camera to the iPhone by Samsung via CorePhotonics patents. In September 2021 LG InnoTek successfully nullified Corephotonics folded camera patents. In September 2023 Patently Apple reported how Apple’s iPhone 15 Pro Max got around Samsung’s Zoom Camera Patents.

Today, the U.S. Patent and Trademark Office officially granted Apple a patent titled "Freeform Folded Optical System," that may provide Apple with a whole new approach to  future periscope-type camera designs.

Apple notes that achieving higher resolution with small package size cameras generally requires use of an image sensor with small pixel size and a good, compact imaging lens system. Advances in technology have achieved reduction of the pixel size in image sensors. However, as image sensors become more compact and powerful, demand for compact imaging lens systems with improved imaging quality performance has increased. In addition, there are increasing expectations for small form factor cameras to be equipped with higher pixel count and/or larger pixel size image sensors (one or both of which may require larger image sensors) while still maintaining a module height that is compact enough to fit into portable electronic devices. Thus, a challenge from an optical system design point of view is to provide an optical system that is capable of capturing high brightness, high resolution images under the physical constraints imposed by small form factor cameras.

Apple's invention/granted patent covers a freeform folded optical system that may, for example, be used in small form factor cameras in mobile multipurpose devices such as iPhones or iPads. Embodiments of the freeform folded optical system are described that include two freeform prisms with optical power and without a lens stack between the prisms.

At least one of the freeform prisms is configured to fold the optical axis of the optical system twice. Thus, embodiments of the freeform folded optical system fold the optical axis three or four times.

Folding the optical axis three or four times in the freeform prisms allows for long focal lengths required for telephoto lens applications without requiring additional lens elements between the prisms.

In addition, the configuration of the freeform folded optical system provides reduced Z-axis height when compared to conventional folded lens systems with similar optical characteristics.

The folded optical system includes two freeform prisms. In at least some embodiments, each freeform prism is formed of an optical plastic material. Each freeform prism has more than three surfaces; however, only three of the surfaces of each freeform prism are presented in this patent.

In embodiments of the folded optical system, the first freeform prism has a first surface that is a transmitting and total internal reflection (TIR) surface that transmits light received from an object field and reflects light received from a second surface of the first freeform prism by TIR to a third surface of the first freeform prism.

The second surface of the first freeform prism is a reflecting surface coated with a mirror coating that reflects light received through the first surface of the first freeform prism back to the first surface of the first freeform prism.

The third surface of the first freeform prism is a transmitting surface that transmits light received from the first surface of the first freeform prism. Thus, the first freeform prism folds the optical axis twice—once at the second surface, and again at the first surface. At least one of the three surfaces of the first freeform prism is a freeform surface.

In some embodiments, an objective lens may be located on the object side of the first freeform prism, for example to correct for aberrations in the optical system. In some embodiments, the objective lens is a rotationally symmetric lens. In some embodiments, at least one of the surfaces of the objective lens is aspherical.

In some embodiments, the objective lens has positive refractive power. In some embodiments, the objective lens is composed of an optical plastic material. In some embodiments, the objective lens is composed of an optical glass material. Using optical glass instead of plastic for the objective lens may, for example, aid in correcting aberrations. In some embodiments, the objective lens is a doublet lens.

Using optical glass instead of plastic for the objective lens may, for example, aid in correcting aberrations.

For more details, review Apple's granted patent 11933949. Apple's lead inventor  on this invention is noted as being Takeyoshi Saiga. He must be very important as there's no LinkedIn profile or any profile on him online. While there isn't a profile, there's a long history of his work at Apple regarding optical system at Justia Patents.