Patent ID: 11933949
Assignee: APPLE INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An optical system, comprising:
in order from an object side of the optical system to an image side of the optical system:
a first freeform prism that includes:
a first surface, a second surface, and a third surface, wherein an optical axis of the optical system traverses the first surface, the second surface, and the third surface,
wherein an angle θ between the first surface of the first freeform prism and the second surface of the first freeform prism is less than or equal to 35 degrees,
wherein the first surface is configured to transmit light incident from an object side into the first freeform prism, and to internally reflect at least a portion of the light that is reflected back to the first surface from within the first freeform prism,
wherein the light incident into the first freeform prism from the object side has no more than two internal reflections within the first freeform prism,
wherein at least one of the first surface, the second surface, or the third surface of the first freeform prism is a freeform surface; and

a second freeform prism that includes:
a first surface, a second surface, and a third surface, wherein the optical axis of the optical system traverses the first surface, the second surface, and the third surface,
wherein the first surface is configured to input light exiting the first freeform prism,
wherein the light input through the first surface of the second freeform prism has a same direction of propagation as the light exiting the first freeform prism and has no more than two internal reflections within the second freeform prism,
wherein at least one of the first surface, the second surface, or the third surface of the second freeform prism is another freeform surface;

wherein the first freeform prism is configured to fold the optical axis of the optical system twice.