公开(公告)号：US11054646B1

公开(公告)日：2021-07-06

申请号：US15886623

申请日：2018-02-01

申请人： Apple Inc.

发明人： Victoria C. Chan ,  John N. Border ,  Jeffrey C. Olson ,  Yury A. Petrov ,  Edward S. Huo ,  Brandon Clarke

IPC分类号： G02B27/01 ,  G02B27/09 ,  G06T19/00

摘要： 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.