US 2019/0101767 A1Published application

Fresnel assembly for light redirection in eye tracking systems

AssigneeFacebook Technologies, LLC

InventorsYing Geng, Yusufu Njoni Bamaxam Sulai, Andrew John Ouderkirk, Brian Wheelwright, Jacques Gollier, Alexander Sohn, Robin Sharma

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Abstract

A head-mounted device (HMD) comprises a display element, a Fresnel assembly, an illumination source, and a camera assembly. The display element outputs image light in a first band of light through a display surface. The optics block directs light from the display element to a target region (e.g., includes a portion of a user's face, eyes, etc.). The Fresnel assembly transmits light in the first band and directs light in a second band different than the first band to a first position. The source illuminates the target area with light in the second band. The camera is located in the first position and captures light in the second band corresponding to light reflected from the target area that is then reflected by the Fresnel assembly toward the camera. A controller may use the captured light to determine tracking information for areas of a user's face (e.g., eyes).

Claims20

Dependent claims

A head-mounted display (HMD) comprising:

a display element configured to output image light in a first band of light through a display surface;
an optics block configured to direct light from the display element to an eyebox, and the eyebox is a region in space occupied by an eye of the user;
a Fresnel assembly configured to transmit light in the first band and direct light in a second band different than the first band to a first position;
an eye tracking system configured to generate eye tracking information, the eye tracking system comprising:
an illumination source configured to illuminate portions of the eyebox with light in the second band,
a camera located in the first position, the camera configured to capture light in the second band corresponding to light reflected from the eye of the user through the optics block and reflected by the Fresnel assembly, and
a controller configured to determine eye tracking information using the captured light in the second band, and
wherein the HMD is configured to adjust the image light based on the eye tracking information.

5 more elements

Dependencies are inferred from the claim text.