Head-mounted display device with Fresnel lenses

Patent metadata

Field	Value
Publication number	US-11054646-B1
Application number	US-201815886623-A
Country	US
Kind code	B1
Filing date	Feb 1, 2018
Priority date	May 11, 2017
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A head-mounted device may include a display system and an optical system in a housing. The display system may have displays that produce images. The optical system may have Fresnel lenses through which a user of the head-mounted device may view the images. The Fresnel lenses may have concentric rings with slope facets and draft facets angled parallel to the chief rays. Light scattering in the Fresnel lenses may be reduced by coating the draft facets with opaque masking material and/or by aligning concentric rings of the opaque masking material that are supported on a transparent substrate with the draft facets. A central portion of the Fresnel lens that is free of facets may be enlarged to reduce scattering. The Fresnel lenses may have wedge-shaped cross-sectional profiles and may have outer portions that are thicker than inner portions. Gradient-index material may be used in forming the Fresnel lenses.

First claim

What is claimed is:

1. A lens having a maximum lateral dimension with opposing first and second ends, comprising:
a center dome portion; and
an outer Fresnel lens portion that radially surrounds the center dome portion and that has slope facets and draft facets, wherein the draft facets are coated with absorptive material, wherein the slope facets are free of the absorptive material, and wherein the center dome portion and the outer Fresnel lens portion have a wedge shaped cross-sectional profile in which the outer Fresnel lens portion has a first thickness at the first end of the maximum lateral dimension of the lens and a second thickness at the second end of the maximum lateral dimension of the lens, the first thickness being greater than the second thickness.

2. The lens defined in claim 1 wherein the center dome portion and the Fresnel lens portion are formed from a gradient-index-of-refraction material.

3. The lens defined in claim 2 wherein the draft facets have an angle that varies radially across the Fresnel lens.

4. The lens defined in claim 1 , wherein the outer Fresnel lens portion comprises a first outer Fresnel lens portion that forms the first end of the maximum lateral dimension and a second outer Fresnel lens that forms the second end of the maximum lateral dimension, wherein the center dome portion is laterally interposed between the first and second outer Fresnel lens portions.

5. A device, comprising:
a display including pixels configured to display images;
a Fresnel lens through which the images are viewable; and
a housing configured to support the display and the Fresnel lens, wherein the Fresnel lens has an inner Fresnel lens element and an outer Fresnel lens element, wherein the inner Fresnel lens element has first Fresnel lens rings, wherein the outer Fresnel lens element has second Fresnel lens rings, wherein the first Fresnel lens rings of the inner Fresnel lens element face the second Fresnel lens rings of the outer Fresnel lens element, wherein the inner Fresnel lens element has a concave surface opposite the first Fresnel lens rings, and wherein the outer Fresnel lens element has a convex surface opposite the second Fresnel lens rings.

6. The device defined in claim 5 wherein the inner Fresnel lens element and the outer Fresnel lens element have an equal number of Fresnel lens rings.

7. The device defined in claim 5 wherein the first Fresnel lens rings of the inner Fresnel lens element have slope facets that are free of absorptive masking material and have draft facets covered with absorptive masking material.

8. The device defined in claim 5 wherein the first Fresnel lens rings of the inner Fresnel lens element have first draft facets with surfaces parallel to chief rays, and wherein the second Fresnel lens rings of the outer Fresnel lens element have second draft facets, each of the second draft facets being parallel to each other and non-parallel with respect to the first draft facets.

9. The device defined in claim 5 wherein the Fresnel lens has a diameter, wherein the inner and outer Fresnel lens elements each have a central dome portion without Fresnel lens rings and an outer portion with Fresnel lens rings, and wherein the central dome portion of the inner and outer Fresnel lens elements has a diameter of at least 20% of the diameter of the lens.

10. The device defined in claim 5 further comprising a field lens interposed between the display and the Fresnel lens.

Assignees

• Apple Inc

Inventors

• Chan Victoria C
• Border John N
• Olson Jeffrey C
• Petrov Yury A
• Huo Edward S
• Clarke Brandon

Classifications

• G02B2027/0123

  comprising devices increasing the field of view · CPC title

• G02B3/08

  with discontinuous faces, e.g. Fresnel lens {(diffractive Fresnel lenses G02B5/1876)} · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G06T19/006

  Mixed reality (object pose determination, tracking or camera calibration for mixed reality G06T7/00) · CPC title