Hybrid lens for head mount display

Abstract

A lens assembly, related methods and constituent optical elements are described. The assembly may be used to direct and focus light for various applications. In one instance, the lens assembly is used in conjunction with one or more sources of light such as projected images or video as part of a virtual reality system. The lens assembly includes two or more optical elements arranged to receive light or direct light through different spatial regions of the assembly at different focal powers corresponding to a first user viewing zone and a second user viewing zone. In one instance, the first user viewing zone is a peripheral viewing zone and the second viewing zone is a primary or non-peripheral viewing zone (or vice versa).

What is claimed is: 
     
         1 . A lens assembly for a headset, the lens assembly comprising:
 at least one hybrid lens, wherein a respective one of the at least one hybrid lens comprises:
 a first lens portion, and 
 a second lens portion; 
   wherein the first lens portion comprises an aspheric optical element and provides a central field of view,   wherein the second lens portion comprises a Fresnel optical element and provides a peripheral field of view,   wherein the second lens portion has an adjacent or annular configuration and arrangement relative to the first lens portion.   
     
     
         2 . The lens assembly of  claim 1 , wherein the second lens portion surrounds at least part of the first lens portion, and/or wherein the second lens portion is located at a side of the first lens portion. 
     
     
         3 . The lens assembly of  claim 1 , wherein the first lens portion and the second lens portion are glued or fused to one another. 
     
     
         4 . The lens assembly of  claim 1 , wherein the aspheric optical element comprises a first lateral length and the Fresnel optical element comprises a second lateral length, and wherein the first lateral length is greater than or equal to the second lateral length. 
     
     
         5 . The lens assembly of  claim 1 , wherein the at least one hybrid lens has a length of from 70 millimeter to 80 millimeter, the first lens portion has a length of from 35 millimeter to 45 millimeter. 
     
     
         6 . The lens assembly of  claim 5 , wherein the at least one hybrid lens has a height of from 25 millimeter to 35 millimeter, the first lens portion has a length of from 15 millimeter to 20 millimeter. 
     
     
         7 . The lens assembly of  claim 6 , wherein the first lens portion has a width of from 30 millimeter to 40 millimeter, and wherein the second lens portion has a width of from 40 millimeter to 50 millimeter. 
     
     
         8 . The lens assembly of  claim 1 , wherein the Fresnel optical element comprises a plurality of grooves, the plurality of grooves having a height of from 2.5 millimeter to 3.0 millimeter, and the plurality of grooves having a spacing between adjacent ones of the plurality of grooves of from 1.5 millimeter to 2.5 millimeter. 
     
     
         9 . The lens assembly of  claim 8 , wherein the Fresnel optical element comprises:
 a first region comprising a first plurality of grooves, the first plurality of grooves having a height of from 2.5 millimeter to 3.0 millimeter; and   a second region comprising a second plurality of grooves, the second plurality of grooves having a height of from 2.0 millimeter to 2.5 millimeter.   
     
     
         10 . The lens assembly of  claim 1 , wherein the Fresnel optical element comprises a plurality of grooves, wherein at least one of a height of the plurality of grooves or a spacing between adjacent ones of the plurality of grooves decreases with increasing distance from the aspheric optical element. 
     
     
         11 . The lens assembly of  claim 1 , wherein the at least one hybrid lens is configured to form a virtual image within a range corresponding to a dark focus distance of a human eye. 
     
     
         12 . The lens assembly of  claim 1 , wherein:
 the first lens portion comprises a cavity configured to receive at least part of the second lens portion, or   the second lens portion comprises a cavity configured to receive at least part of the first lens portion.   
     
     
         13 . The lens assembly of  claim 1 , wherein the first lens portion corresponds to a primary viewing zone of a human eye and the second lens portion corresponds to a peripheral viewing zone of the human eye. 
     
     
         14 . The lens assembly of  claim 1 , wherein the at least one hybrid lens comprises:
 a first hybrid lens, the first hybrid lens comprising the second lens portion of the first hybrid lens disposed about a first lateral side of the first lens portion of the first hybrid lens; and   a second hybrid lens, the second hybrid lens comprising the second lens portion of the second hybrid lens disposed about a second lateral side of the first lens portion of the second hybrid lens.   
     
     
         15 . A headset, comprising:
 a housing;   at least one display coupled to the housing; and   at least one hybrid lens coupled to the housing;   wherein a respective one of the at least one hybrid lens comprises a first lens portion and a second lens portion, the first lens portion comprising an aspheric optical element and the second lens portion comprising a Fresnel optical element, the first lens portion providing a central field of view, the second lens portion providing a peripheral field of view, and the second lens portion having an adjacent or annular configuration and arrangement relative to the first lens portion.   
     
     
         16 . The headset of  claim 15 , wherein a back focal distance between the at least one display and the at least one hybrid lens is from 25 millimeter to 35 millimeter. 
     
     
         17 . The headset of  claim 15 , wherein the at least one display comprises a curved display, the curved display comprising a first curvature portion corresponding to a primary viewing zone and a second curvature portion corresponding to a peripheral viewing zone, wherein the first curvature portion comprises a first radius of curvature of from 124 millimeter to 128 millimeter, and wherein the second curvature portion comprises a second radius of curvature of from 25 millimeter to 5,645 millimeter. 
     
     
         18 . The headset of  claim 17 , wherein the second radius of curvature comprises a variable radius of curvature, the variable radius of curvature comprising a first curvature region and a second curvature region, the first curvature region disposed between the first curvature portion and the second curvature region, the first curvature region having a first variable radius of curvature varying within a first range of from 25 millimeter to 128 millimeter, and the second curvature region having a second variable radius of curvature varying within a second range of from 25 millimeter to 5,645 millimeter, wherein a minimum radius of curvature delineates the first curvature region from the second curvature region. 
     
     
         19 . The headset of  claim 15 , wherein the headset is a virtual reality headset. 
     
     
         20 . A method of projecting an image, the method comprising:
 emitting a first portion of light from at least one display of a virtual reality headset, the first portion of the light passing through a first lens portion comprising an aspheric optical element, the first lens portion providing a central field of view; and   emitting a second portion of light from the at least one display of the virtual reality headset, the second portion of the light passing through a second lens portion comprising a Fresnel optical element, the second lens portion providing a peripheral field of view;   wherein the first lens portion and the second lens portion define a hybrid lens of the virtual reality headset, the second lens portion having an adjacent or annular configuration and arrangement relative to the first lens portion.