Binocular virtual image projection using single projector

Abstract

A head-mounted display system comprises a projector, one or more eyepieces, and left and right biasing optics. The one or more eyepieces include an incoupling optical element operable to receive virtual light generated by the projector, a waveguide operable to propagate the virtual light toward left and right portions of the one or more eyepieces, and left and right light distributing elements operable to output the virtual light toward left and right eyes of a user. The left and right biasing optics are operable to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

Description

PATENT Attorney Docket No.: 101782-015900WO-1472378 Client Ref. No.: ML-5007WOBINOCULAR VIRTUAL IMAGE PROJECTION USING SINGLE PROJECTORBACKGROUND OF THE INVENTION

[0001] Modem computing and display technologies have facilitated the development of systems for so called "virtual reality" or "augmented reality" experiences, wherein digitally reproduced images or portions thereof are presented to a viewer in a manner wherein they seem to be, or may be perceived as, real. A virtual reality, or "VR," scenario typically involves the presentation of digital or virtual image information without transparency to other actual real-world visual input; an augmented reality, or "AR," scenario typically involves the presentation of digital or virtual image information as an augmentation to visualization of the actual world around the viewer.

[0002] Referring to FIG. 1, an augmented reality scene 100 is depicted. The user of an AR technology sees a real -world park-like setting 106 featuring people, trees, buildings in the background, and a real-world concrete platform 120. The user also perceives that he / she "sees" "virtual content" such as a robot statue 110 standing upon the real-world concrete platform 120. and a flying cartoon-like avatar character 102 which seems to be a personification of a bumble bee. The robot statue 110 and the flying cartoon-like avatar character 102 are "virtual" in that they do not exist in the real world. Because the human visual perception system is complex, it is challenging to produce AR technology7that facilitates a comfortable, natural-feeling, rich presentation of virtual image elements amongst other virtual or real-world imagery elements.

[0003] Despite the progress made in these display technologies, there is a need in the art for improved methods and systems related to augmented reality systems, particularly, display systems.SUMMARY OF THE INVENTION

[0004] The present invention relates generally to methods and systems related to projection display systems including wearable displays. More particularly, embodiments of the present invention provide head-mounted display systems having a single projector architecture.Merely by way of example, some embodiments of the invention relate to a single projection system for projection of any field of view (FOV) single or full color RGB virtual images for augmented reality (AR) or mixed reality (MR) applications. In some examples, the placement of the projection system with respect to the eyepiece waveguides is such that the virtual images can be projected at infinity or given a certain depth of focus by angling the left and right eyepiece waveguides with respect to the projection system and the user's FOV. A single projection system can significantly lower the complexity and cost of a thinner more wearable AR / MR system for a user while not removing the user from the augmented immersive experience.

[0005] A summary of the various embodiments of the invention is provided below as a list of examples. As used below, any reference to a series of examples is to be understood as a reference to each of those examples disjunctively (e.g., "Examples 1-4" is to be understood as "Examples 1, 2, 3, or 4").

[0006] Example 1 is a head-mounted display system comprising: a projector; a monolithic eyepiece including: an incoupling optical element operable to receive virtual light generated by the projector; a waveguide operable to propagate the virtual light toward left and right portions of the monolithic eyepiece; and left and right light distributing elements operable to output the virtual light toward left and right eyes of a user; and left and right biasing optics operable to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

[0007] Example 2 is the head-mounted display system of example 1, wherein: the left and right biasing optics each comprise a first biased lens and a second biased lens; the first biased lens is characterized by a first optical thickness in a first portion of the first biased lens adjacent the projector greater than a second optical thickness in a second portion of the first biased lens distal from the projector; and the second biased lens is characterized by a third optical thickness in a first portion of the second biased lens adjacent the projector less than a second optical thickness in a second portion of the second biased lens distal from the projector.

[0008] Example 3 is the head-mounted display system of example(s) 1-2, wherein the left and right biasing optics each comprise: a rear refractive lens disposed between the monolithic eyepiece and an eye side of the head-mounted display system; and a front refractive lensdisposed between the monolithic eyepiece and a world side of the head-mounted display system.

[0009] Example 4 is the head-mounted display system of example(s) 1-3. wherein: the rear refractive lens comprises a negative lens; and the front refractive lens comprises a positive lens.

[0010] Example 5 is the head-mounted display system of example(s) 1-4, wherein the left and right biasing optics each comprise: a rear Fresnel lens disposed between the monolithic eyepiece and an eye side of the head-mounted display system; and a front Fresnel lens disposed between the monolithic eyepiece and a world side of the head-mounted display system.

[0011] Example 6 is the head-mounted display system of example(s) 1-5, wherein the virtual light generated by the proj ector is simultaneously propagated by the waveguide toward the left and right portions of the monolithic eyepiece.

[0012] Example 7 is the head-mounted display system of example(s) 1-6. wherein the left and right light distributing elements are disposed in the left and right portions of the monolithic eyepiece, respectively.

[0013] Example 8 is the head-mounted display system of example(s) 1-7, wherein the left and right light distributing elements comprise a left diffractive structure with a first optical power biased with respect to the center of the left diffractive structure and a right diffractive structure with a second optical power biased with respect to the center of the right diffractive structure, respectively.

[0014] Example 9 is the head-mounted display system of example(s) 1-8, wherein the monolithic eyepiece is characterized by a curvature.

[0015] Example 10 is the head-mounted display system of example(s) 1-9, wherein the curvature comprises a convex curvature with respect to an eye side of the head-mounted display system.

[0016] Example 11 is the head-mounted display system of example(s) 1-10, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

[0017] Example 12 is a method of operating a head-mounted display system, the method comprising: generating virtual light by a projector; receiving, by an incoupling opticalelement of a monolithic eyepiece, the virtual light generated by the projector, wherein the monolithic eyepiece comprises a left light distributing element and a right light distributing element; propagating, by a waveguide of the monolithic eyepiece, the virtual light toward the left light distributing element and the right light distributing element of the monolithic eyepiece; outputting, by left light distributing element and the right light distributing element of the monolithic eyepiece, the virtual light toward a left eye and a right eye of a user, respectively; and angling the virtual light outputted from the left light distributing element and the right light distributing element such that a left virtual light origination point overlaps with a right virtual light origination point.

[0018] Example 13 is the method of example 12, wherein angling the virtual light comprises passing the virtual light through a left light biasing optic and a right light biasing optic.

[0019] Example 14 is the method of example(s) 12-13, wherein the monolithic eyepiece is characterized by a curvature.

[0020] Example 15 is the method of example(s) 12-14, wherein the curvature comprises a convex curv ature with respect to an eye side of the head-mounted display system.

[0021] Example 16 is the method of example(s) 12-15, wherein angling the virtual light outputted from the left light distributing element and the right light distributing element comprises passing the virtual light through the monolithic eyepiece characterized by the curv ature.

[0022] Example 17 is the method of example(s) 12-16, wherein the left light distributing element comprises a left diffractive structure with a first optical power and the right light distributing element comprises a right diffractive structure with a second optical power.

[0023] Example 18 is the method of example(s) 12-17, wherein the first optical power is biased with respect to the center of the left diffractive structure and the second optical power is biased with respect to the center of the right diffractive structure.

[0024] Example 19 is a head-mounted display system comprising: a projector; a left eyepiece including: a left incoupling optical element operable to receive virtual light generated by the projector; a left waveguide operable to propagate the virtual light; and left light distributing elements operable to output the virtual light toward a left eye of a user; a right eyepiece overlapping and laterally offset from the left eyepiece, the right eyepieceincluding: a right incoupling optical element operable to receive virtual light generated by the projector; a right waveguide operable to propagate the virtual light; and right light distributing elements operable to output the virtual light toward a right eye of the user; and left and right biasing optics operable to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

[0025] Example 20 is the head-mounted display system of example 19, wherein: the left biasing optics comprises: a left rear refractive lens disposed between the left eyepiece and an eye side of the head-mounted display system; and a left front refractive lens disposed between the left eyepiece and a world side of the head-mounted display system; and the right biasing optics comprises: a right rear refractive lens disposed between the right eyepiece and the eye side of the head-mounted display system; and a right front refractive lens disposed between the right eyepiece and the world side of the head-mounted display system.

[0026] Example 21 is the head-mounted display system of example(s) 19-20, wherein: the left biasing optics comprises: a left rear Fresnel lens disposed between the left eyepiece and an eye side of the head-mounted display system; and a left front Fresnel lens disposed between the left eyepiece and a world side of the head-mounted display system; and the right biasing optics comprises: a right rear Fresnel lens disposed between the right eyepiece and the eye side of the head-mounted display system; and a right front Fresnel lens disposed between the right eyepiece and the world side of the head-mounted display system.

[0027] Example 22 is the head-mounted display system of example(s) 19-21, wherein the virtual light generated by the projector is simultaneously propagated by the left waveguide and the right waveguide.

[0028] Example 23 is the head-mounted display system of example(s) 19-22, wherein the projector is a Liquid Cry stal on Silicon (LCoS) projector.

[0029] Example 24 is the head-mounted display system of example(s) 19-23, wherein the left eyepiece and the right eyepiece are tilted with respect to a plane of projection of the headmounted display system.

[0030] Example 25 is the head-mounted display system of example(s) 19-24, wherein the left eyepiece and the right eyepiece are tilted such that the left incoupling optical element andthe right incoupling optical element are positioned closer to an eye side of the head-mounted display system.

[0031] Example 26 is the head-mounted display system of example(s) 19-25. wherein the left eyepiece and the right eyepiece are tilted such that the left incoupling optical element and the right incoupling optical element are positioned closer to a world side of the head-mounted display system.

[0032] Example 27 is the head-mounted display system of example(s) 19-26, wherein: the left incoupling optical element operates in a transmissive mode and the right incoupling optical element operates in a reflective mode; or the left incoupling optical element operates in the reflective mode and the right incoupling optical element operates in the transmissive mode.

[0033] Example 28 is a method of operating a head-mounted display system, the method comprising: generating virtual light by a projector; receiving, by a left incoupling optical element of a left eyepiece, the virtual light generated by the projector; propagating the virtual light by a left waveguide of the left eyepiece; outputting, by left light distributing elements of the left eyepiece, the virtual light toward a left eye of a user; receiving, by a right incoupling optical element of a right eyepiece, the virtual light generated by the projector; propagating the virtual light by a right waveguide of the right eyepiece; outputting, by right light distributing elements of the right eyepiece, the virtual light toward a right eye of the user; and angling the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

[0034] Example 29 is the method of example 28, wherein the virtual light outputted from the left and right light distributing elements is angled by left and right biasing optics.

[0035] Example 30 is the method of example(s) 28-29, wherein the virtual light outputted from the left and right light distributing elements is angled by a curvature of the left and right eyepieces, wherein the left and right eyepieces are curved in a convex configuration with respect to an eye side of the head-mounted display system.

[0036] Example 31 is the method of example(s) 28-30, wherein the virtual light outputted from the left and right light distributing elements is angled by left and right powered eyepiece elements.

[0037] Example 32 is a head-mounted display system comprising: a projector; and a monolithic eyepiece including: an incoupling optical element operable to receive virtual light generated by the projector; a waveguide operable to propagate the virtual light toward left and right portions of the monolithic eyepiece; and left and right light distributing elements operable to output the virtual light toward left and right eyes of a user; and wherein the monolithic eyepiece is curved in a convex configuration with respect to an eye side of the head-mounted display system so as to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

[0038] Example 33 is the head-mounted display system of example 32, wherein the virtual light generated by the projector is simultaneously propagated by the waveguide toward the left and right portions of the monolithic eyepiece.

[0039] Example 34 is the head-mounted display system of example(s) 32-33, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

[0040] Example 35 is the head-mounted display system of example(s) 32-34, wherein the incoupling optical element operates in a transmissive mode.

[0041] Example 36 is the head-mounted display system of example(s) 32-35, wherein the incoupling optical element operates in a reflective mode.

[0042] Example 37 is a head-mounted display system comprising: a projector; a left eyepiece including: a left incoupling optical element operable to receive virtual light generated by the projector; a left waveguide operable to propagate the virtual light; and left light distributing elements operable to output the virtual light toward a left eye of a user; and a right eyepiece separate from the left eyepiece, the right eyepiece including: a right incoupling optical element operable to receive virtual light generated by the projector; a right waveguide operable to propagate the virtual light; and right light distributing elements operable to output the virtual light toward a right eye of the user; wherein the left and right eyepieces are curved in a convex configuration with respect to an eye side of the headmounted display system so as to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

[0043] Example 38 is the head-mounted display system of example 37, wherein the virtual light generated by the projector is simultaneously propagated by the left waveguide and the right waveguide.

[0044] Example 39 is the head-mounted display system of example(s) 37-38, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

[0045] Example 40 is the head-mounted display system of example(s) 37-39, wherein: the left incoupling optical element operates in a transmissive mode and the right incoupling optical element operates in a reflective mode; or the left incoupling optical element operates in the reflective mode and the right incoupling optical element operates in the transmissive mode.BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 illustrates a user's view of augmented reality (AR) through an AR device.

[0047] FIG. 2A illustrates a cross-sectional, side view of an example of a set of stacked waveguides that each includes an incoupling optical element according to an embodiment of the present invention.

[0048] FIG. 2B illustrates a perspective view of an example of one or more stacked waveguides of FIG. 2A.

[0049] FIG. 2C illustrates a top-down, plan view of an example of one or more stacked waveguides of FIGS. 2A and 2B.

[0050] FIG. 3 is a simplified illustration of an eyepiece waveguide having a combined pupil expander according to an embodiment of the present invention.

[0051] FIG. 4 illustrates an example of wearable display system according to an embodiment of the present invention.

[0052] FIG. 5 shows a perspective view of a wearable device according to an embodiment of the present invention.

[0053] FIG. 6 is a simplified plan view of elements of an AR headset according to an embodiment of the present invention.

[0054] FIG. 7A illustrates a cross-sectional, side view of an example of a display system such as a head-mounted display system according to an embodiment of the present invention.

[0055] FIG. 7B illustrates a cross-sectional, side view of an example of a display system such as a head-mounted display system according to an embodiment of the present invention.

[0056] FIG. 8 illustrates a cross-sectional, side view of an example of a display system that uses independent left and right tilted eyepiece waveguides according to an embodiment of the present invention.

[0057] FIG. 9A illustrates a cross-sectional, side view of an example of a display system having a monolithic eyepiece and sets of biasing optics according to an embodiment of the present invention.

[0058] FIG. 9B illustrates a cross-sectional, side view of an example of a display system 900 having separate left and right eyepieces and sets of biasing optics according to an embodiment of the present invention.

[0059] FIGS. 9C and 9D illustrate cross-sectional, side views of a display system showing how biasing optics can angle virtual light to form virtual light origination points at a plane of projection according to an embodiment of the present invention.

[0060] FIG. 9E illustrates a cross-sectional, side view of an example of a display system 970 having a monolithic eyepiece 971 and powered diffractive elements according to an embodiment of the present invention.

[0061] FIGS. 9F - 91 are plan view illustrations of the powered diffractive elements utilized in display system 970 according to an embodiment of the present invention.

[0062] FIGS. 10A and 10B illustrate cross-sectional, side views of examples of a display system having separate and tilted left and right eyepieces and sets of biasing optics according to an embodiment of the present invention.

[0063] FIG. 11 A illustrates a cross-sectional, side view of an example of a display system having a curved monolithic eyepiece according to an embodiment of the present invention.

[0064] FIG. 1 IB illustrates a cross-sectional, side view of an example of a display system having curved left and right eyepieces according to an embodiment of the present invention.

[0065] FIG. 12 is a simplified flowchart illustrating a method of operating a head-mounted display system according to an embodiment of the present invention.

[0066] FIG. 13 is a simplified flowchart illustrating a method of operating a head-mounted display system according to an embodiment of the present invention.

[0067] FIG. 14 is a simplified block diagram illustrating components of an AR system or display system according to an embodiment of the present invention.DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0068] Many head-mounted display systems utilize two projection systems, one projector for the left eyepiece and another for the right eyepiece. Reducing the number of projectors from two to one would benefit such systems by reducing complexity7and cost. In some cases, a single projector with a single monolithic eyepiece waveguide has been used as a monocle device to sequentially switch between sending images to left and right sides of the eyepiece. Without proper angling of the virtual light that is outcoupled from the eyepiece, such systems can lead to vergence-accommodation conflict, which is a visual phenomenon that occurs when the brain receives conflicting cues from the eyes' vergence and accommodation.

[0069] The present invention relates generally to methods and systems related to projection display systems including wearable displays. More particularly, embodiments of the present invention provide head-mounted display systems having a single projector architecture with a single monolithic eyepiece or separate left and right eyepieces. Embodiments further provide for angling of virtual light that is output from the eyepiece using one of several methods, including biasing optics on the user and world sides of the eyepiece, curved eyepieces, and / or powered eyepiece elements. By angling the virtual light that is output from the eyepiece, any vergence-accommodation conflict experienced by the user is eliminated or greatly diminished. Embodiments are suitable for augmented reality (AR) or mixed reality (MR) applications in which a head-mounted display is utilized.

[0070] Many benefits are achieved by way of the present disclosure. For example, the mono-projector architecture described herein can allow for lower power consumption, lower weight, and cheaper cost of AR / MR wearables. Embodiments allow the use of split binocular exit pupils (EPs) for two-dimensional (2D) image augmentation at infinite or fixed focal depth using a single central projector. Embodiments further avoid the complexity and issuesarising from a sequential left and right image projection system, which can have vergence accommodation issues for the user perceiving a virtual image.

[0071] Reference will now be made to the drawings, in which like reference numerals refer to like parts throughout. Unless indicated otherwise, the drawings are schematic not necessarily drawn to scale.

[0072] With reference now to FIG. 2A, in some embodiments, light impinging on a waveguide may need to be redirected to incouple that light into the waveguide. An incoupling optical element may be used to redirect and incouple the light into its corresponding waveguide. Although referred to as "incoupling optical element" through the specification, the incoupling optical element need not be an optical element and may be a non-optical element. FIG. 2A illustrates a cross-sectional, side view- of an example of a set of stacked waveguides 200 that each includes an incoupling optical element. The waveguides may each be configured to output light of one or more different wavelengths, or one or more different ranges of wavelengths. Light from a projector is injected into the set of stacked waveguides 200 and outcoupled to a user as described more fully below.

[0073] The illustrated set of stacked waveguides 200 includes w aveguide 202, waveguide 204, and waveguide 206. Each waveguide includes an associated incoupling optical element (which may also be referred to as a light input area on the waveguide), with, e.g., incoupling optical element 203 disposed on a major surface (e.g., an upper major surface) of waveguide 202, incoupling optical element 205 disposed on a major surface (e.g., an upper major surface) of waveguide 204. and incoupling optical element 207 disposed on a major surface (e.g., an upper major surface) of waveguide 206. In some embodiments, one or more of the incoupling optical elements may be disposed on the bottom major surface of the respective w aveguide (particularly where one or more incoupling optical elements are reflective, deflecting optical elements). As illustrated, the incoupling optical element 203. the incoupling optical element 205, and the incoupling optical element 207 may be disposed on the upper major surface of waveguide 202, waveguide 204, and w aveguide 206, respectively (or the top of the next lower waveguide), particularly where those incoupling optical elements are transmissive, deflecting optical elements. In some embodiments, the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 maybe disposed in the body of the waveguide 202. waveguide 204, and waveguide 206. respectively. In some embodiments, as discussed herein, the incoupling optical element 203,the incoupling optical element 205, and the incoupling optical element 207 are wavelength- selective, such that they selectively redirect one or more wavelengths of light, while transmitting other wavelengths of light. While illustrated on one side or comer of waveguide 202, waveguide 204, and waveguide 206, respectively, it will be appreciated that the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 may be disposed in other areas of waveguide 202, waveguide 204, and waveguide 206, respectively, in some embodiments.

[0074] As illustrated, the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 may be laterally offset from one another. In some embodiments, each incoupling optical element may be offset such that it receives light without that light passing through another incoupling optical element. For example, each of the incoupling optical element 203, the incoupling optical element 205. and the incoupling optical element 207 may be configured to receive light from a different projector and may be separated (e.g., laterally spaced apart) from other incoupling optical elements such that it substantially does not receive light from the other ones of the incoupling optical elements.

[0075] Each waveguide also includes associated light distributing elements, with, e.g., light distributing elements 210 disposed on a major surface (e.g.. a top major surface) of waveguide 202, light distributing elements 212 disposed on a major surface (e g., atop major surface) of waveguide 204, and light distributing elements 214 disposed on a major surface (e.g., a top major surface) of waveguide 206. In some other embodiments, the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 may be disposed on a bottom major surface of associated waveguide 202, waveguide 204, and waveguide 206, respectively. In some other embodiments, the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 may be disposed on both top and bottom major surfaces of associated waveguide 202, waveguide 204, and waveguide 206, respectively; or the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 may be disposed on different ones of the top and bottom major surfaces in different associated waveguide 202, waveguide 204, and waveguide 206, respectively.

[0076] Waveguide 202, waveguide 204, and waveguide 206 may be spaced apart and separated by. e.g., gas. liquid, and / or solid layers of material. For example, as illustrated in FIG. 2A, layer 208 may separate waveguide 202 and waveguide 204 and layer 209 mayseparate waveguide 204 and waveguide 206. In some embodiments, layer 208 and layer 209 are formed of low refractive index materials (that is. materials having a lower refractive index than the material forming the immediately adjacent one of waveguide 202, waveguide 204, or waveguide 206). Preferably, the refractive index of the material forming layer 208 and / or layer 209 is 0.05 or more, or 0.10 or less than the refractive index of the material forming the waveguide 202, the waveguide 204, or the waveguide 206. Advantageously, layer 208 and layer 209 having the lower refractive index may function as cladding layers that facilitate total internal reflection (TIR) of light through the waveguide 202, the waveguide 204, and the waveguide 206 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some embodiments, the layer 208 and the layer 209 are formed of air. While not illustrated, it will be appreciated that the top and bottom of the illustrated set of stacked waveguides 200 may include immediately neighboring cladding layers.

[0077] Preferably, for ease of manufacturing and other considerations, the material forming the waveguide 202, the waveguide 204, and the waveguide 206 are similar or the same, and the material forming the layer 208 and the layer 209 are similar or the same. In some embodiments, the material forming the waveguide 202, the waveguide 204. and the waveguide 206 may be different between one or more waveguides, and / or the material forming the layer 208 and the layer 209 may be different, while still holding to the various refractive index relationships noted above.

[0078] With continued reference to FIG. 2A, light ray 218, light ray 219, and light ray 220 are incident on the set of stacked waveguides 200. It will be appreciated that the light ray 218, the light ray 219, and the light ray 220 may be injected into the waveguide 202, the waveguide 204, and the waveguide 206 by one or more projectors (not shown).

[0079] In some embodiments, light ray 218, the light ray 219, and the light ray 220 have different properties, e.g., different wavelengths or different ranges of wavelengths, which may correspond to different colors. The incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 each deflect the incident light such that the light propagates through a respective one of the waveguide 202, the waveguide 204, or the waveguide 206 by TIR. In some embodiments, the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 each selectively deflect one or more particular wavelengths of light, while transmitting other wavelengths to an underlying waveguide and associated incoupling optical element.

[0080] For example, incoupling optical element 203 may be configured to deflect light ray 218, which has a first wavelength or range of wavelengths, while transmitting light ray 219 and light ray 220, which have different second and third wavelengths or ranges of wavelengths, respectively. The light ray 219 transmitted through the waveguide 202 impinges on and is deflected by the incoupling optical element 205, which is configured to deflect light of a second wavelength or range of wavelengths. The light ray 220 is deflected by the incouphng optical element 207. which is configured to selectively deflect light of third wavelength or range of wavelengths.

[0081] With continued reference to FIG. 2A, the light ray 218, the light ray 219, and the light ray 220 are deflected such that they propagate through corresponding waveguide 202, waveguide 204, and waveguide 206, respectively; that is, the incoupling optical element 203. the incoupling optical element 205, and the incoupling optical element 207 of each waveguide deflects the light into the corresponding waveguide 202, waveguide 204, or waveguide 206 to incouple light into that corresponding waveguide. The light ray 218, the light ray 219, and the light ray 220 are deflected at angles that cause the light to propagate through the respective waveguide 202. waveguide 204, and waveguide 206 by TIR. The light ray 218, the light ray 219, and the light ray 220 propagate through the respective waveguide202, waveguide 204, and waveguide 206 by TIR until impinging on the waveguide's corresponding light distributing elements: the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214. where they are outcoupled to provide out-coupled light rays 216.

[0082] With reference now to FIG. 2B, a perspective view of an example of the set of stacked waveguides 200 of FIG. 2A is illustrated. As noted above, the light ray 218, the light ray 219, and the light ray 220 are incoupled and deflected by the incoupling optical element203, the incoupling optical element 205, and the incoupling optical element 207, respectively, and then propagate by TIR within the waveguide 202. the waveguide 204, and the waveguide 206, respectively. The light ray 218, the light ray 219, and the light ray 220 then impinge on the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214, respectively. The light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 deflect the light ray 218, the light ray 219, and the light ray 220 so that they propagate towards the outcoupling optical elements 222, the outcoupling optical elements 224, and the outcoupling optical elements 226, respectively.

[0083] In some embodiments, the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or distribute light to the outcoupling optical elements 222, the outcoupling optical elements 224, and the outcoupling optical elements 226 and, in some embodiments, may also increase the beam or spot size of this light as it propagates to the outcoupling optical elements. In some embodiments, the light distributing elements 210, the light distributing elements 212. and the light distributing elements 214 may be omitted and the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 may be configured to deflect light directly to the outcoupling optical elements 222, the outcoupling optical elements 224, and the outcoupling optical elements 226. For example, with reference to FIG. 2A, the light distributing elements 210. the light distributing elements 212, and the light distributing elements 214 may be replaced with the outcoupling optical elements 222, the outcoupling optical elements 224, and the outcoupling optical elements 226, respectively. In some embodiments, the outcoupling optical elements 222. the outcoupling optical elements 224, and the outcoupling optical elements 226 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct light to the eye of the user. It will be appreciated that the OPEs may be configured to increase the dimensions of the eye box in at least one axis and the EPEs may be configured to increase the eye box in an axis crossing, e.g., orthogonal to, the axis of the OPEs. For example, each OPE may be configured to redirect a portion of the light striking the OPE to an EPE of the same waveguide, while allowing the remaining portion of the light to continue to propagate down the waveguide. Upon impinging on the OPE again, another portion of the remaining light is redirected to the EPE, and the remaining portion of that portion continues to propagate further down the waveguide, and so on. Similarly, upon striking the EPE, a portion of the impinging light is directed out of the waveguide towards the user, and a remaining portion of that light continues to propagate through the waveguide until it strikes the EPE again, at which time another portion of the impinging light is directed out of the w aveguide, and so on. Consequently, a single beam of incoupled light may be "replicated" each time a portion of that light is redirected by an OPE or EPE, thereby forming a field of cloned beams of light. In some embodiments, the OPE and / or EPE may be configured to modify a size of the beams of light. In some embodiments, the functionality of the light distributing elements 210, the light distributing elements 212. and the light distributing elements 214 and the outcoupling optical elements 222. the outcoupling optical elements 224, and the outcoupling optical elements 226 are combined in a combined pupil expander as discussed in relation to FIG. 2E.

[0084] Accordingly, with reference to FIGS. 2A and 2B, in some embodiments, the set of stacked waveguides 200 includes the waveguide 202, the waveguide 204. and the waveguide 206; the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207; the light distributing elements 210, the light distributing elements 212, and the light distributing elements 214 (e.g., OPEs); and the outcoupling optical elements 222. the outcoupling optical elements 224, and the outcoupling optical elements 226 (e.g.. EPs) for each component color. The waveguide 202, the waveguide 204. and the waveguide 206 may be stacked with an air gap / cladding layer between each one. The incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 redirect or deflect incident light (with different incoupling optical elements receiving light of different wavelengths) into its waveguide. The light then propagates at an angle which will result in TIR within the waveguide 202, the waveguide 204, and the waveguide 206, respectively. In the example shown, light ray 218 (e.g., blue light) is deflected by the incoupling optical element 203, and then continues to bounce down the waveguide, interacting with the light distributing element 210 (e.g., OPEs) and then the outcoupling optical element 222 (e.g., EPs), in a manner described earlier. The light ray 219 and the light ray 220 (e.g., green and red light, respectively) will pass through the waveguide 202, with light ray 219 impinging on and being deflected by incoupling optical element 205. The light ray 219 then bounces down the waveguide 204 via TIR, proceeding on to its light distributing element 212 (e.g., OPEs) and then the outcoupling optical element 224 (e.g., EPs). Finally, light ray 220 (e.g., red light) passes through the waveguide 206 to impinge on the incoupling optical element 207 of the waveguide 206. The incoupling optical element 207 deflects the light ray 220 such that the light ray propagates to light distributing element 214 (e.g., OPEs) by TIR, and then to the outcoupling optical element 226 (e.g., EPs) by TIR. The outcoupling optical element 226 then finally out-couples the light ray 220 to the viewer, who also receives the outcoupled light from the other waveguides: the waveguide 202 and the waveguide 204.

[0085] FIG. 2C illustrates a top-down, plan view- of an example of the set of stacked waveguides 200 of FIGS. 2A and 2B. As illustrated, the waveguide 202, the waveguide 204. and the waveguide 206, along with each waveguide's associated light distributing element: the light distributing element 210, light distributing element 212, and light distributing element 214 and the associated outcoupling optical elements: the outcoupling optical elements 222, the outcoupling optical elements 224, and the outcoupling optical elements226, may be vertically aligned. However, as discussed herein, the incoupling optical element 203, the incoupling optical element 205, and the incoupling optical element 207 are not vertically aligned; rather, the incoupling optical elements are preferably nonoverlapping (e.g., laterally spaced apart as seen in the top-dow n or plan view). As discussed further herein, this nonoverlapping spatial arrangement facilitates the injection of light from different resources into different waveguides on a one-to-one basis, thereby allowing a specific light source to be uniquely coupled to a specific waveguide. In some embodiments, arrangements including nonoverlapping spatially separated incoupling optical elements may be referred to as a shifted pupil system, and the incoupling optical elements within these arrangements may correspond to sub pupils.

[0086] FIG. 3 is a simplified illustration of an eyepiece waveguide having a combined pupil expander according to an embodiment of the present invention. In the example illustrated in FIG. 3, the eyepiece 304 utilizes a combined OPE / EPE region in a single-side configuration. Referring to FIG. 3, the eyepiece 304 includes a substrate 320 in which incoupling optical element 322 and a combined OPE / EPE region 324, also referred to as a combined pupil expander (CPE), are provided. Incident light ray 330 is incoupled via the incoupling optical element 322 and outcoupled as output light rays 332 via the combined OPE / EPE region 324.

[0087] The combined OPE / EPE region 324 includes gratings corresponding to both an OPE and an EPE that spatially overlap in the x-direction and the y-direction. In some embodiments, the gratings corresponding to both the OPE and the EPE are located on the same side of a substrate 320 such that either the OPE gratings are superimposed onto the EPE gratings or the EPE gratings are superimposed onto the OPE gratings (or both). In other embodiments, the OPE gratings are located on the opposite side of the substrate 320 from the EPE gratings such that the gratings spatially overlap in the x-direction and the y-direction but are separated from each other in the z-direction (i.e., in different planes). Thus, the combined OPE / EPE region 324 can be implemented in either a single-sided configuration or in a tw o- sided configuration.

[0088] FIG. 4 illustrates an example of w earable display system 430 into which the various waveguides and related systems disclosed herein may be integrated. With reference to FIG.4. the wearable display system 430 includes a display 432, and various mechanical and electronic modules and systems to support the functioning of the display 432. The display432 may be coupled to a frame 434, which is wearable by a user 440 (also referred to as a viewer or a display system user) and which is configured to position the display 432 in front of the eyes of the user 440. The display 432 may be considered eyewear in some embodiments. In some embodiments, a speaker 436 is coupled to the frame 434 and configured to be positioned adjacent to the ear canal of the user 440 (in some embodiments, another speaker, not shown, may optionally be positioned adjacent to the other ear canal of the user to provide stereo / shapeable sound control). The wearable display system 430 may also include one or more microphones or other devices to detect sound. In some embodiments, the microphone is configured to allow the user to provide inputs or commands to the wearable display system 430 (e.g., the selection of voice menu commands, natural language questions), and / or may allow audio communication with other persons (e.g., with other users of similar display systems). The microphone may further be configured as a peripheral sensor to collect audio data (e.g., sounds from the user and / or environment). In some embodiments, the wearable display system 430 may further include one or more outwardly directed environmental sensors configured to detect objects, stimuli, people, animals, locations, or other aspects of the world around the user. For example, environmental sensors may include one or more cameras, which may be located, for example, facing outward so as to capture images similar to at least a portion of an ordinary field of view of the user 440. In some embodiments, the wearable display system may also include a peripheral sensor, which may be separate from the frame 434 and attached to the body of the user 440 (e.g., on the head, torso, an extremity, of the user 440). The peripheral sensor may be configured to acquire data characterizing a physiological state of the user 440 in some embodiments. For example, the sensor may be an electrode.

[0089] The display 432 is operatively coupled by a communications link, such as by a wired lead or wireless connectivity, to a local data processing module which may be mounted in a variety of configurations, such as fixedly attached to the frame 434, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removably attached to the user 440 (e.g., in a backpack-style configuration, in a belt-coupling sty le configuration). Similarly, the sensor may be operatively coupled by a communications link, e.g., a wired lead or wireless connectivity, to the local processor and data module. The local processing and data module may comprise a hardware processor, as well as digital memory , such as nonvolatile memory- (e.g., flash memory or hard disk drives), both of which may be utilized to assist in the processing, caching, and storage of data. Optionally, the local processor and datamodule may include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, and so on. The data may include data a) captured from sensors (which may be, e.g., operatively coupled to the frame 434 or otherwise attached to the user 440), such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, radio devices, gyros, and / or other sensors disclosed herein; and / or b) acquired and / or processed using remote processing module 452 and / or remote data repository 454 (including data relating to virtual content), possibly for passage to the display 432 after such processing or retrieval. The local processing and data module may be operatively coupled by communication links 438 such as via wired or wireless communication links, to the remote processing and data module 450, which can include the remote processing module 452, the remote data repository 454, and a battery 460. The remote processing module 452 and the remote data repository 454 can be coupled by communication links 456 and communication links 458 to remote processing and data module 450 such that these remote modules are operatively coupled to each other and available as resources to the remote processing and data module 450. In some embodiments, the remote processing and data module 450 may include one or more of the image capture devices, microphones, inertial measurement units, accelerometers, compasses, GPS units, radio devices, and / or gy ros. In some other embodiments, one or more of these sensors may be attached to the frame 434, or may be standalone structures that communicate with the remote processing and data module 450 by wired or wireless communication pathways.

[0090] With continued reference to FIG. 4, in some embodiments, the remote processing and data module 450 may comprise one or more processors configured to analyze and process data and / or image information, for instance including one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, and so on. In some embodiments, the remote data repository 454 may comprise a digital data storage facility, which may be available through the internet or other networking configuration in a "cloud" resource configuration. In some embodiments, the remote data repository 454 may include one or more remote servers, which provide information, e.g., information for generating augmented reality content, to the local processing and data module and / or the remote processing and data module 450. In some embodiments, all data is stored and all computations are performed in the local processing and data module, allowing fully autonomous use from a remote module. Optionally, an outside system (e.g., a system of one or more processors, one or more computers) that includes CPUs, GPUs, and so on, mayperform at least a portion of processing (e.g., generating image information, processing data) and provide information to, and receive information from, the illustrated modules, for instance, via wireless or wired connections.

[0091] FIG. 5 shows a perspective view of a wearable device 500 according to an embodiment of the present invention. Wearable device 500 includes a frame 502 configured to support one or more projectors 523 at various positions along an interior-facing surface of frame 502, as illustrated. In some embodiments, projectors 523 can be attached at positions near temples 506. Alternatively, or in addition, another projector could be placed in position 508. Such projectors may, for instance, include or operate in conjunction with one or more liquid cry stal on silicon (LCoS) modules, micro-LED displays, or fiber scanning devices. In some embodiments, light from projectors 523 or projectors disposed in position 508 could be guided into eyepieces 504 for display to eyes of a user. Projectors placed at positions 512 can be somewhat smaller on account of the close proximity this gives the projectors to the waveguide system. The closer proximity can reduce the amount of light lost as the waveguide system guides light from the projectors to eyepiece 504. In some embodiments, the projectors at positions 512 can be utilized in conjunction with projectors 523 or projectors disposed in position 508. While not depicted, in some embodiments, projectors could also be located at positions beneath eyepieces 504. Wearable device 500 is also depicted including sensors 514 and sensors 516. Sensors 514 and sensors 516 can take the form of forwardfacing and lateral-facing optical sensors configured to characterize the real-world environment surrounding wearable device 500.

[0092] FIG. 6 is a simplified plan view of elements of an AR headset. In FIG. 6, elements of an optical stack 600 are illustrated. The AR headset may include a pair of optical stacks, one for each eye of the user. The optical stack 600 includes a front Extended Depth Of Field (EDOF) lens 610 and front optics 612 that receive world light propagating from right to left toward the eye 660 of the user. The optical stack 600 also includes a dimmer 602, an eyepiece 604, a rear EDOF lens 652, an eye tracking (ET) structure, and an optional prescription lens insert 662. The eye tracking structure may include one or more eye tracking cameras 605 disposed along / outside a periphery of the rear EDOF lens 652 and one or more illumination sources 613 disposed along / outside the periphery of the rear EDOF lens 652 or within an illumination layer disposed between the rear EDOF lens 652 and the eyepiece 604.

[0093] Dimmer 602 includes a world side linear polarizer 620, a first quarter waveplate 622, a liquid crystal panel 624. a second quarter waveplate 626, and an eye side linear polarizer 628, for example, a hard coated linear polarizer (HC-LP) with a surface open to air hard coated for handling purposes. Eyepiece 604 includes three eyepiece waveguide layers: blue active layer 630, green active layer 632, and red active layer 634. Although a three- layer eyepiece (i.e.. an eyepiece including three eyepiece waveguide layers) is illustrated in FIG. 6, this is not required and in other embodiments, a six-layer eyepiece structure can be utilized with, for example, two depth planes.

[0094] The eye tracking system and the rear EDOF lens 652 collectively form a rear EDOF and ET structure 606. One or more prisms may be integrated with the rear EDOF lens 652 and may be operable to reflect light from an outward radial direction of the optical stack 600 to an eye side axial direction of the optical stack 600, or from a world side axial direction to an outward radial direction. For example, each of the wedge prisms aligned with illumination sources may reflect illumination light from the inward radial direction to the eye side axial direction, and each of the wedge prisms aligned with eye tracking cameras may reflect illumination light from the world side axial direction to the outward radial direction.

[0095] FIG. 7A illustrates a cross-sectional, side view of an example of a display system 700 such as a head-mounted display system according to an embodiment of the present invention. The display system 700 includes a projector 723 that generates virtual light 718, also referred to as virtual content, that is injected into a waveguide 702 of a monolithic eyepiece 704. While a single waveguide is illustrated, it is to be understood that the waveguide 702 may include a set of stacked waveguides, with each waveguide in the set of stacked waveguides being configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. The waveguide 702 may include an incoupling optical element 703 disposed on a major surface (e.g.. an upper major surface) of the waveguide 702.

[0096] The incoupling optical element 703 may operate in a transmissive mode or in a reflective mode and may redirect one or more wavelengths of the virtual light 718 to simultaneously propagate toward left and right portions of the monolithic eyepiece 704. Each of the left and right portions of the monolithic eyepiece 704 may include light distributing elements 710 that output the virtual light 718 toward an eye of the user. The light distributing elements 710 for the left and right portions of the monolithic eyepiece 704 may be disposedon a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguide 702.

[0097] FIG. 7B illustrates a cross-sectional, side view of an example of a display system 750 such as a head-mounted display system according to an embodiment of the present invention. The display system 750 includes a projector 773 that generates virtual light 768 that is injected into each of the waveguides 752 of left and right eyepieces 754. In some examples, the left and right eyepieces 754 may be laterally offset and at least partially overlapping such that the virtual light 768 passes through each of the waveguides 752 of the left and right eyepieces 754. While a single waveguide is illustrated in each of the left and right eyepieces 754, it is to be understood that the waveguides 752 may each include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. Each of the waveguides 752 may include an incoupling optical element 753 disposed on a major surface (e.g., an upper major surface or a bottom major surface) of the waveguides 752.

[0098] The incoupling optical elements 753 may operate in a transmissive mode or in a reflective mode. For example, the incoupling optical element 753 closest to the projector 773 (e.g., the right eyepiece 754) may operate in the transmissive mode and the incoupling optical element 753 furthest from the projector 773 (e g., the left eyepiece 754) may operate in the reflective mode. The incoupling optical elements 753 may redirect one or more wavelengths of the virtual light 768 to simultaneously propagate through the waveguides 752 of the left and right eyepieces 754. Each of the left and right eyepieces 754 may include light distributing elements 760 that output the virtual light 768 toward an eye of the user. The light distributing elements 760 for the left and right eyepieces 754 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguides 752.

[0099] FIG. 8 illustrates a cross-sectional, side view of an example of a display system 800 that uses independent left and right tilted eyepiece waveguides that transmit light back to the user in a manner so as to form a more natural virtual augmented image in the real world according to an embodiment of the present invention. The eyepiece waveguides can have the same dimensions or can differ in at least one dimension to obtain overlap of the input coupler gratings. In the illustrated example, the display system 800 includes a projector 823 that generates virtual light 818 that is injected into each of the waveguides 802 of left and righteyepieces 804. In some examples, the left and right eyepieces 804 may be laterally offset and at least partially overlapping such that the virtual light 818 passes through each of the waveguides 802. While a single waveguide is illustrated in each of the eyepieces 804, it is to be understood that the waveguides 802 may each include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths.

[0100] Each of the waveguides 802 may include an incoupling optical element 803 disposed on a major surface (e.g., an upper major surface or a bottom major surface) of the waveguides 802. The incoupling optical elements 803 may operate in a transmissive mode or in a reflective mode. For example, the incoupling optical element 803 closest to the projector 823 (e.g., the right eyepiece 804) may operate in the transmissive mode and the incoupling optical element 803 furthest from the projector 823 (e.g., the left eyepiece 804) may operate in the reflective mode. The incoupling optical elements 803 may redirect one or more wavelengths of the virtual light 818 to simultaneously propagate through the waveguides 802 of the left and right eyepieces 804. The left and right eyepieces 804 may include light distributing elements 810 that output the virtual light 818 toward eyes 860 of the user. The light distributing elements 810 for the left and right eyepieces 804 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguides 802.

[0101] Each of the left and right eyepieces 804 may be tilted with respect to a plane of projection of the display system 800. For example, as shown in the illustrated example, the eyepieces 804 may be tilted such that the sides of the eyepieces 804 that include the incoupling optical elements 803 may be positioned closer to the eye side of the head-mounted display sy stem 800 (or further from the plane of projection) compared to the sides of the eyepieces 804 that include the light distributing elements 810. Alternatively, the eyepieces 804 may be tilted such that the sides of the eyepieces 804 that include the incoupling optical elements 803 may be positioned closer to the world side of the head-mounted display system 800 (or closer to the plane of projection) compared to the sides of the eyepieces 804 that include the light distributing elements 810. The angle (or "tilt angle") formed by the eyepieces 804 and the plane of projection may be between 0.5 and 4 degrees, and preferably between 1 and 2 degrees. For some AR waveguide implementations, for example, with an interpupillary distance (IPD) of 62 mm and a width from the left edge of the left eyepiece to the right edge of the right eyepiece of 100 mm, achieving this angle will result in tilting ofeach eyepiece so that the outer edge of the eyepiece is tilted toward the world side by about 1.85 mm with respect to the inner edge of the eyepiece.

[0102] In some embodiments, referring to the right waveguide 802 and right incoupling optical element 803, the grating period, which is inversely related to the grating pitch measured between grating teeth, can be selected such that light rays of a given wavelength incident on right incoupling optical element 803 on right side waveguide 802 at an angle less than zero (i.e., tilted with respect to the plane of the waveguide at an acute angle as illustrated in FIG. 8) is incoupled along a direction centered on the plane of the waveguide. For this grating with increased grating period and decreased grating pitch, if light, at the given wavelength, was incident at normal incidence, the light would be incoupled along a direction tilted up by a positive angle with respect to the plane of the waveguide. Thus, the increased grating period utilizes an incoupling grating that is stronger than conventional designs.Accordingly, light tilted at an acute angle with respect to the plane of the waveguide, will be incoupled into right side waveguide 802 and experience TIR as the light propagates down the waveguide. When the light is outcoupled, it will be outcoupled at normal incidence and directed toward the center of the plane of propagation.

[0103] Referring to FIG. 8 once again and left waveguide 802 and left incoupling optical element 803, the grating period, can be selected such that light rays incident on left incoupling optical element 803 at a non-normal angle of incidence (i.e., tilted with respect to the plane of the waveguide 802 are also incoupled along a direction centered on the plane of the eyepiece. Thus, the increased grating period utilizes an incoupling grating that is stronger than conventional designs. Similar to the light outcoupled from right waveguide 802, since light tilted at an acute angle with respect to the plane of the waveguide is incoupled into left side waveguide 802 and propagates along the plane of the waveguide, the light experience TIR as the light propagates down the waveguide and when the light is outcoupled, it will be outcoupled at normal incidence and directed toward the center of the plane of propagation.

[0104] Additional description related to incoupling gratings that can receive light at nonnormal incidence and incouple light parallel to the plane of the waveguide, thereby enabling outcoupling normal to the plane of the waveguide is provided in commonly assigned U.S. Patent No. 11,536,972, issued on December 27, 2022, and entitled "Method and System for Dual Projector Waveguide Displays With Wide Field of View Using A Combined PupilExpander-Extractor (CPE)," the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

[0105] FIG. 9A illustrates a cross-sectional, side view of an example of a display system 900 having a monolithic eyepiece 904 and sets of biasing optics according to an embodiment of the present invention. The display system 900 includes a projector 923 that generates virtual light 918 that is injected into a waveguide 902 of the monolithic eyepiece 904. While a single waveguide is illustrated, it is to be understood that the waveguide 902 may include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. The waveguide 902 may include an incoupling optical element 903 disposed on a major surface (e.g., a lower major surface) of the waveguide 902.

[0106] The incoupling optical element 903 may operate in a transmissive mode or in a reflective mode and may redirect one or more wavelengths of the virtual light 918 to simultaneously propagate toward left and right portions of the monolithic eyepiece 904. Each of the left and right portions of the monolithic eyepiece 904 may include light distributing elements 910 that output the virtual light 918 toward an eye of the user. The light distributing elements 910 for the left and right portions of the monolithic eyepiece 904 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguide 902.

[0107] Eye side biasing optics 952 are used for both the left and right eye and may be disposed below (i.e., on the eye side of) the light distributing elements 910 of the monolithic eyepiece 904. Additionally, world side biasing optics 912 for the left and right eyes may be disposed above (i.e., on the world side of) the light distributing elements 910 of the monolithic eyepiece 904. The eye side biasing optics 952 and the world side biasing optics 912 are not symmetric about their centers, but are biased toward either the side of the lens adjacent the projector 923 (i.e.. the inner side) or the side of the lens distal from the projector 923 (i.e., the outer side). As a result, the direction of propagation of a plane wave incident at normal incidence on the eye side biasing optics 952 and the world side biasing optics 912 will be tilted either toward the inner side or toward the outer side depending on the asymmetry of the set of optics. In the embodiment illustrated in FIG. 9A, the positive lens used to implement the world side biasing optics 912 is biased toward the inner side and the negativelens used to implement the eye side biasing optics 952 is biased toward the outer side. As a result, the virtual light 916 will appear to originate at the virtual light origination points 954.

[0108] Referring to FIG. 9A. left and right biasing optics are illustrated, with each of the left and right biasing optics including a first biased lens (i.e., a world side biased lens) and a second biased lens (i.e., an eye side biased lens). The first biased lens (i.e., the world side lens) is characterized by a first optical thickness in a first portion of the first biased lens adjacent the projector 923 greater than a second optical thickness in a second portion of the first biased lens distal from the projector 923. In the illustrated embodiment, the lens is asymmetric about the center of the lens, with the thickest part of the lens being located on the inner region of the lens. In other embodiments, the shape of the lens could be symmetric, but the material making up the lens could have a higher index of refraction in the inner region of the lens or a lower index of refraction in the outer portion of the lens.

[0109] The second biased lens (i.e., the eye side lens) is characterized by a third optical thickness in a first portion of the second biased lens adjacent the projector 923 less than a second optical thickness in a second portion of the second biased lens distal from the projector 923. In the illustrated embodiment, the lens is asymmetric about the center of the lens, with the thickest part of the lens being located on the outer region of the lens. In other embodiments, the shape of the lens could be symmetric, but the material making up the lens could have a higher index of refraction in the outer region of the lens or a lower index of refraction in the inner region of the lens.

[0110] Accordingly, the eye side biasing optics 952 may angle the virtual light 916 outputted from the light distributing elements 910 such that virtual light origination points 954 associated with the virtual light 916 outputted from the eye side biasing optics 952 overlap with each other at the plane of projection. The virtual light origination points 954 can be determined by projecting the virtual light 916 outputted from the eye side biasing optics 952 to the world side until reaching the plane of projection. In some embodiments, the virtual light origination points 954 can have a finite two-dimensional extent and represent a region or field of view and the use of the term "point" is not intended to connote an area lacking two-dimensional extent.[OHl] World side biasing optics 912 for the left and right eyes may be disposed above (i.e., on the world side of) the light distributing elements 910 of the monolithic eyepiece 904. The world side biasing optics 912 may correct for any angling applied to the world light bythe eye side biasing optics 952 such that the world light appears to the user to be unaltered by the display system 900. In various examples, the world side biasing optics 912 and eye side biasing optics 952 may include push / pull lenses, refractive lenses, convex lenses, concave lenses, Fresnel lenses, geometric phase lenses, among other possibilities.

[0112] FIG. 9B illustrates a cross-sectional, side view of an example of a display system 900 having separate left and right eyepieces 904 and sets of biasing optics, i.e., world side biasing optics 912 and eye side biasing optics 952. The display system 900 includes a projector 923 that generates virtual light 918 that is injected into each of the waveguides 902 of left and right eyepieces 904. In some examples, the left and right eyepieces 904 may be laterally offset and at least partially overlapping such that the virtual light 918 passes through each of the waveguides 902. While a single waveguide is illustrated in each of the eyepieces 904, the waveguides 902 may each include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. Each of the waveguides 902 may include an incoupling optical element 903 disposed on a major surface (e.g., an upper major surface or a bottom major surface) of the waveguides 902.

[0113] The incoupling optical elements 903 may operate in a transmissive mode or in a reflective mode. For example, the incoupling optical element 903 closest to the projector 923 (e.g., the right eyepiece 904) may operate in the transmissive mode and the incoupling optical element 903 furthest from the projector 923 (e.g., the left eyepiece 904) may operate in the reflective mode. The incoupling optical elements 903 may redirect one or more wavelengths of the virtual light 918 to simultaneously propagate through the waveguides 902 of the left and right eyepieces 904. Each of the left and right eyepieces 904 may include light distributing elements 910 that output the virtual light 918 toward an eye of the user. The light distributing elements 910 for the left and right eyepieces 904 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguides 902.

[0114] Eye side biasing optics 952 for the left and right eyes may be disposed below (i.e., on the eye side of) the light distributing elements 910 of the eyepieces 904. The eye side biasing optics 952 may angle the virtual light 916 outputted from the light distributing elements 910 such that virtual light origination points 954 associated with the virtual light 916 outputted from the eye side biasing optics 952 overlap with each other at the plane ofprojection. The virtual light origination points 954 can be determined by projecting the virtual light 916 outputted from the eye side biasing optics 952 to the world side until reaching the plane of projection. Left and right world side biasing optics 912 may be disposed above (i.e., on the world side of) the light distributing elements 910 of the eyepieces 904. The world side biasing optics 912 may correct for any angling applied to the world light by the eye side biasing optics 952 such that the world light appears to the user to be unaltered by the display system 900. In various examples, the world side biasing optics 912 and the eye side biasing optics 952 may include push / pull lenses, refractive lenses, convex lenses, concave lenses, Fresnel lenses, geometric phase lenses, among other possibilities.

[0115] FIGS. 9C and 9D illustrate cross-sectional, side views of the display system 900 showing how eye side biasing optics 952 can angle the virtual light 916 outputted from the eye side biasing optics 952 to form virtual light origination points 954 at the plane of projection according to an embodiment of the present invention. Use of the eye side biasing optics 952 can help accommodate for the vergence of the virtual images from the left and right eyes which can also be to a fixed focal depth.

[0116] FIG. 9E illustrates a cross-sectional, side view of an example of a display system 970 having a monolithic eyepiece 971 and powered diffractive elements according to an embodiment of the present invention. The display system 970 includes a projector 972 that generates virtual light 973 that is injected into a waveguide 975 of the monolithic eyepiece 971. While a single waveguide is illustrated, it is to be understood that the waveguide 975 may include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. The waveguide 975 may include an incoupling optical element 903 disposed on a major surface (e.g., a lower major surface) of the waveguide 975.

[0117] The waveguide 975 may include a left light distributing optical element 976 disposed on a major surface (e.g., an upper major surface) of the left side of the waveguide975 and a left light outcoupling optical element 977 disposed on a major surface (e.g., a lower major surface) of the left side of the waveguide 975. The left light distributing optical element 976 and the left light outcoupling optical element 977 operate together as a combined pupil expander (CPE) to orthogonally spread light in the plane of the waveguide and outcouple light to the user. In some embodiments, the left light distributing optical element976 and the left light outcoupling optical element 977 are interchanged to be positioned onthe opposing side of the waveguide as appropriate to the particular application. As described more fully below, the left light distributing optical element 976 and the left light outcoupling optical element 977 include optical power that in biased toward either the inner side or the outer side of the optical element.

[0118] The waveguide 975 also includes a right light distributing optical element 978 disposed on a major surface (e.g., an upper major surface) of the right side of the waveguide 975 and a right light outcoupling optical element 979 disposed on a major surface (e.g.. a lower major surface) of the right side of the waveguide 975. Similar to the left light distributing optical element 976 and the left light outcoupling optical element 977 operating together as a CPE, the right light distributing optical element 978 and the right light outcoupling optical element 979 can operate as a CPE and their locations can be interchanged. As described more fully below, the left light distributing optical element 976 and the left light outcoupling optical element 977 include optical power that in biased toward either the inner side or the outer side of the optical element.

[0119] FIGS. 9F - 91 are plan view illustrations of the powered diffractive elements utilized in display system 970 according to an embodiment of the present invention. In these figures, the grating pitch is varied in a manner to implement optical power as a function of position across the eyepiece waveguide. Thus, the grating periodicity is controlled to not only introduce OPE / EPE functions, but also to focus / defocus light in order to introduce optical power. In these figures, the optical power is not symmetric with respect to the center of the diffractive structure, but is asymmetric to introduce biased optical power similar to that achieved using refractive lenses in the embodiments shown in FIGS. 9A - 9D.

[0120] FIG. 9F illustrates a topography of the left light distributing optical element 976. The edges correspond to the lowest effective index of refraction and the central circle 981 corresponds to the highest effective index of refraction. As will be evident to one of skill in the art, the effective index of refraction will be implemented using grating structures that complement the grating structures used implement the OPE functionality. As a result, the varying effective index of refraction across the left light distributing optical element 976 corresponds to the varying index of refraction present in world side biasing optics 912 adjacent the left side of the waveguide 902. Thus, in a manner similar to the biased refractive optics shown in FIG. 9A. powered diffractive optical elements can be utilized to implement biased optics as shown in FIGS. 9E.

[0121] FIG. 9G illustrates a topography of the left light outcoupling optical element 977. The edges correspond to the lowest effective index of refraction and the central circle 982 corresponds to the highest effective index of refraction. As will be evident to one of skill in the art, the effective index of refraction will be implemented using grating structures that complement the grating structures used implement the EPE functionality7. As a result, the varving effective index of refraction across the left light outcoupling optical element 977 corresponds to the varying index of refraction present in eye side biasing optics 952 adjacent the left side of the waveguide 902. Thus, in a manner similar to the biased refractive optics shown in FIG. 9A, powered diffractive optical elements can be utilized to implement biased optics as shown in FIGS. 9F.

[0122] FIG. 9H illustrates a topography of the right light distributing optical element 978. The edges correspond to the lowest effective index of refraction and the central circle 983 corresponds to the highest effective index of refraction. As will be evident to one of skill in the art, the effective index of refraction will be implemented using grating structures that complement the grating structures used implement the OPE functionality. As a result, the varying effective index of refraction across the right light distributing optical element 978 corresponds to the varying index of refraction present in world side biasing optics 912 adjacent the right side of the waveguide 902. Thus, in a manner similar to the biased refractive optics shown in FIG. 9A, powered diffractive optical elements can be utilized to implement biased optics as shown in FIGS. 9H.

[0123] FIG. 91 illustrates a topography of the right light outcoupling optical element 979. The edges correspond to the lowest effective index of refraction and the central circle 984 corresponds to the highest effective index of refraction. As will be evident to one of skill in the art, the effective index of refraction w ill be implemented using grating structures that complement the grating structures used implement the EPE functionality. As a result, the varying effective index of refraction across the right light outcoupling optical element 979 corresponds to the varying index of refraction present in eye side biasing optics 952 adjacent the right side of the w aveguide 902. Thus, in a manner similar to the biased refractive optics shown in FIG. 9A, powered diffractive optical elements can be utilized to implement biased optics as shown in FIGS. 91.

[0124] Thus, in a manner similar to the biased refractive optics shown in FIG. 9A, powered diffractive optical elements as shown in FIGS. 9F - 91 can be utilized to implement biased optics as shown in FIGS. 9E.

[0125] FIGS. 10A and 10B illustrate cross-sectional, side views of examples of a display system 1000 having separate and tilted left and right eyepieces 1004 and sets of biasing optics according to an embodiment of the present invention. Referring to each of FIGS. 10A and 10B, the display system 1000 includes a projector 1023 that generates virtual light 1018 that is injected into each of the waveguides 1002 of left and right eyepieces 1004. The left and right eyepieces 1004 may be laterally offset and at least partially overlapping such that the virtual light 1018 passes through each of the waveguides 1002. While a single waveguide is illustrated in each of the eyepieces 1004, the waveguides 1002 may each include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. Each of the waveguides 1002 may include an incoupling optical element 1003 disposed on a major surface (e.g., an upper major surface or a bottom major surface) of the waveguides 1002.

[0126] The incoupling optical elements 1003 may operate in a transmissive mode or in a reflective mode. For example, the incoupling optical element 1003 closest to the projector 1023 (e g., the right eyepiece 1004) may operate in the transmissive mode and the incoupling optical element 1003 furthest from the projector 1023 (e.g., the left eyepiece 1004) may operate in the reflective mode. The incoupling optical elements 1003 may redirect one or more wavelengths of the virtual light 1018 to simultaneously propagate through the waveguides 1002 of the left and right eyepieces 1004. Each of the left and right eyepieces 1004 may include light distributing elements 1010 that output the virtual light 1018 toward an eye of the user. The light distributing elements 1010 for the left and right eyepieces 1004 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguides 1002.

[0127] Left and right eye side biasing optics 1052 may be disposed below (i.e., on the eye side of) the light distributing elements 1010 of the eyepieces 1004. The eye side biasing optics 1052 may angle the virtual light 1016 outputted from the distributing elements 1010 such that virtual light origination points 1054 associated with the virtual light 1016 outputted from the eye side biasing optics 1052 overlap with each other at the plane of projection. The virtual light origination points 1054 can be determined by projecting the virtual light 1016outputted from the eye side biasing optics 1052 to the world side until reaching the plane of projection. Left and right world side biasing optics 1012 may be disposed above (i.e., on the world side of) the light distributing elements 1010 of the eyepieces 1004. The world side biasing optics 1012 may correct for any angling applied to the world light by the eye side biasing optics 1052 such that the world light appears to the user to be unaltered by the display system 1000. In various examples, the world side biasing optics 1012 and eye side biasing optics 1052 may include push / pull lenses, refractive lenses, convex lenses, concave lenses. Fresnel lenses, geometric phase lenses, among other possibilities.

[0128] Each of the left and right eyepieces 1004 may be tilted with respect to a plane of projection of the display system 1000. In the example shown in FIG. 10A, the eyepieces 1004 may be tilted such that the sides of the eyepieces 1004 that include the incoupling optical elements 1003 may be positioned closer to the eye side of the head-mounted display system 1000 (or further from the plane of projection) compared to the sides of the eyepieces 1004 that include the light distributing elements 1010. In the example shown in FIG. 10B, the eyepieces 1004 may be tilted such that the sides of the eyepieces 1004 that include the incoupling optical elements 1003 may be positioned closer to the world side of the headmounted display system 1000 (or closer to the plane of projection) compared to the sides of the eyepieces 1004 that include the light distributing elements 1010. The angle (or "tilt angle") formed by the eyepieces 1004 and the plane of projection may be between 0.5 and 4 degrees, and preferably between 1 and 2 degrees.

[0129] FIG. 11A illustrates a cross-sectional, side view of an example of a display system 1100 having a curved monolithic eyepiece 1104 according to an embodiment of the present invention. The display system 1100 includes a projector 1123 that generates virtual light 1118 that is injected into a waveguide 1102 of the monolithic eyepiece 1104. While a single waveguide is illustrated, the waveguide 1102 may include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. The waveguide 1102 may include an incoupling optical element 1103 disposed on a major surface (e.g., an upper major surface) of the waveguide 1102.

[0130] The incoupling optical element 1103 may operate in a transmissive mode or in a reflective mode and may redirect one or more wavelengths of the virtual light 1118 to simultaneously propagate toward left and right portions of the monolithic eyepiece 1104. Each of the left and right portions of the monolithic eyepiece 1104 may include lightdistributing elements 1110 that output the virtual light 1118 toward an eye of the user. The light distributing elements 1110 for the left and right portions of the monolithic eyepiece 1104 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguide 1102.

[0131] The monolithic eyepiece 1104 may have a cylindrical or spherical curvature that is convex from the perspective of the eye side of display system 1100 and concave from the perspective of the world side of display system 1100. The curvature of the monolithic eyepiece 1104 may angle the virtual light 11 16 passing therethrough such that virtual light origination points associated with the virtual light 1116 outputted from the monolithic eyepiece 1104 overlap with each other at the plane of projection. The virtual light origination points can be determined by projecting the virtual light 1116 outputted from the monolithic eyepiece 1104 to the world side until reaching the plane of projection.

[0132] For some AR waveguide implementations, for example, with an interpupillary distance (IPD) of 62 mm and a width from the left edge of the eyepiece to the right edge of the eyepiece of 100 mm, achieving the curvature illustrated in FIG. 11A will result in curving of the eyepiece so that the outer edge of the eyepiece is tilted toward the world side with respect to the center of the eyepiece by about 1.85 mm. Moreover, if the curvature of the eyepiece is cylindrical, then cylindrical biasing optic(s) based on the biasing optics illustrated in FIG. 9A can be utilized to provide optical powder in the direction orthogonal to the cylindrical optical power provided by the cylindrical curvature of the eyepiece.

[0133] FIG. 1 IB illustrates a cross-sectional, side view of an example of a display system 1150 having curved left and right eyepieces 1154. The display system 1150 includes a projector 1173 that generates virtual light 1168 that is injected into each of the waveguides 1152 of left and right eyepieces 1154. The left and right eyepieces 1154 may be laterally offset and at least partially overlapping such that the virtual light 1168 passes through each of the waveguides 1152. While a single waveguide is illustrated in each of the eyepieces 1154, the waveguides 1 152 may each include a set of stacked waveguides each configured to output light of one or more wavelengths, or one or more different ranges of wavelengths. Each of the waveguides 1152 may include an incoupling optical element 1153 disposed on a major surface (e.g., an upper major surface or a bottom major surface) of the waveguides 1152.

[0134] The incoupling optical elements 1153 may operate in a transmissive mode or in a reflective mode. For example, the incoupling optical element 1153 closest to the projector1173 (e.g., the left eyepiece 1154) may operate in the transmissive mode and the incoupling optical element 1153 furthest from the projector 1173 (e.g., the right eyepiece 1154) may operate in the reflective mode. The incoupling optical elements 1153 may redirect one or more wavelengths of the virtual light 1168 to simultaneously propagate through the waveguides 1152 of the left and right eyepieces 1154. Each of the left and right eyepieces 1154 may include light distributing elements 1160 that output the virtual light 1168 toward an eye of the user. The light distributing elements 1160 for the left and right eyepieces 1154 may be disposed on a top major surface, a bottom major surface, or both top and bottom major surfaces of the waveguides 1152.

[0135] The left and right eyepieces 1154 may have a cylindrical or spherical curvature that is convex from the perspective of the eye side of display system 1150 and concave from the perspective of the world side of display system 1150. The curvature of the left and right eyepieces 1154 may angle the virtual light 1166 passing therethrough such that virtual light origination points associated with the virtual light 1166 outputted from the left and right eyepieces 1154 overlap with each other at the plane of projection. The virtual light origination points can be determined by projecting the virtual light 1166 outputted from the left and right eyepieces 1154 to the world side until reaching the plane of projection.

[0136] FIG. 12 is a simplified flowchart illustrating a method 1200 of operating a headmounted display system (e.g., display systems 900, 1100) according to an embodiment of the present invention. The method 1200 includes, at step 1210, generating virtual light (e.g., virtual light 916, 1116) by a projector (e.g., projectors 923, 1123).

[0137] The method 1200 further includes, at step 1212, receiving, by an incoupling optical element (e g., incoupling optical elements 903, 1103) of a monolithic eyepiece (e g., monolithic eyepieces 904, 1104), the virtual light generated by the projector.

[0138] The method 1200 further includes, at step 1214, propagating, by a waveguide (e.g., waveguides 902, 1102) of the monolithic eyepiece, the virtual light toward left and right portions of the monolithic eyepiece.

[0139] The method 1200 further includes, at step 1216, outputting, by left and right light distributing elements (e.g., light distributing elements 910, 1110) of the monolithic eyepiece, the virtual light toward left and right eyes of a user.

[0140] The method 1200 further includes, at step 1218, angling the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point (e.g., virtual light origination point 954) overlaps with a right virtual light origination point (e.g., virtual light origination point 954). In some examples, the virtual light outputted from the left and right light distributing elements may be angled by left and right biasing optics (e.g., eye side biasing optics 952). In some examples, the virtual light outputted from the left and right light distributing elements may be angled by a curvature of the monolithic eyepiece.

[0141] FIG. 13 is a simplified flowchart illustrating a method 1300 of operating a headmounted display system (e.g., display systems 900, 1000, 1100) according to an embodiment of the present invention. The method 1300 includes, at step 1310, generating virtual light (e.g., virtual light 916, 1016, 1116) by a projector (e.g., projectors 923, 1023, 1123).

[0142] The method 1300 further includes, at step 1312, receiving, by a left incoupling optical element (e.g., incoupling optical elements 903, 1003, 1103) of a left eyepiece (e.g., eyepieces 904, 1004, 1104), the virtual light generated by the projector.

[0143] The method 1300 further includes, at step 1314, propagating, by a left waveguide (e.g., waveguides 902, 1002, 1102) of the left eyepiece, the virtual light toward left light distributing elements (e.g., light distributing elements 910, 1010, 1110) of the left eyepiece.

[0144] The method 1300 further includes, at step 1316, outputting, by the left light distributing elements, the virtual light toward a left eye of a user.

[0145] The method 1300 further includes, at step 1318, receiving, by a right incoupling optical element (e.g., incoupling optical elements 903, 1003, 1103) of a right eyepiece (e.g., eyepieces 904, 1004, 1104), the virtual light generated by the projector.

[0146] The method 1300 further includes, at step 1320, propagating, by a right waveguide (e.g., waveguides 902, 1002. 1102) of the right eyepiece, the virtual light toward nght light distributing elements (e.g., light distributing elements 910, 1010, 1110) of the right eyepiece.

[0147] The method 1300 further includes, at step 1322, outputting, by the right light distributing elements, the virtual light toward a right eye of the user.

[0148] The method 1300 further includes, at step 1324, angling the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point (e.g., virtual light origination point 954, 1054) overlaps with a right virtual light originationpoint (e.g., virtual light origination point 954, 1054). In some examples, the virtual light outputted from the left and right light distributing elements may be angled by left and right biasing optics (e.g., eye side biasing optics 952, eye side biasing optics 1052). In some examples, the virtual light outputted from the left and right light distributing elements may be angled by a curvature of the left and right eyepieces or by a mechanical system (e.g., worm gear, push pin, etc.) which can help modulate the extent of a tilt of the left and right eyepieces or help modulate the extent of at least one curvature (e.g.. the cylindrical curvature).

[0149] It should be appreciated that the specific steps illustrated in FIGS. 12 and 13 provide particular methods of operating a display system according to an embodiment of the present invention. Other sequences of steps may also be performed according to alternative embodiments. For example, alternative embodiments of the present invention may perform the steps outlined above in a different order. Moreover, the individual steps illustrated in FIGS. 12 and 13 may include multiple sub-steps that may be performed in various sequences as appropriate to the individual step. Furthermore, additional steps may be added or removed depending on the particular applications. One of ordinary skill in the art would recognize many variations, modifications, and alternatives.

[0150] FIG. 14 is a simplified block diagram illustrating components of an AR system 1400 or display system according to an embodiment of the present invention. AR system 1400 as illustrated in FIG. 14 may be incorporated into the AR devices as described herein. FIG. 14 provides a schematic illustration of one embodiment of AR system 1400 that can perform some or all of the steps of the methods provided by various embodiments. It should be noted that FIG. 14 is meant only to provide a generalized illustration of various components, any or all of which may be utilized as appropriate. FIG. 14, therefore, broadly illustrates how individual system elements may be implemented in a relatively separated or relatively more integrated manner.

[0151] AR system 1400 is shown comprising hardware elements that can be electrically coupled via a bus 1405, or may otherwise be in communication, as appropriate. The hardware elements may include one or more processors 1410, including without limitation one or more general-purpose processors and / or one or more special-purpose processors such as digital signal processing chips, graphics acceleration processors, and / or the like; one or more input devices 1430. which can include without limitation a mouse, a keyboard, a camera, and / or the like; and one or more output devices 1440, which can include withoutlimitation a display device, a printer, and / or the like. Additionally, AR system 1400 may further include an eye tracking system that can provide the user's eye gaze location to the AR system.

[0152] AR system 1400 may further include and / or be in communication with storage device(s) 1420 (e.g., one or more non-lransitory storage devices), which can comprise, without limitation, local and / or network accessible storage, and / or can include, without limitation, a disk drive, a drive array, an optical storage device, a solid-state storage device, such as a random access memory (RAM), and / or a read-only memory (ROM), which can be programmable, flash-updateable, and / or the like. Such storage devices may be configured to implement any appropriate data stores, including without limitation, various file systems, database structures, and / or the like.

[0153] AR system 1400 might also include a communications subsystem 1450. which can include without limitation a modem, a network card (wireless or wired), an infrared communication device, a wireless communication device, and / or a chipset such as a Bluetooth™ device, an 802. 11 device, a WiFi device, a WiMax device, cellular communication facilities, etc., and / or the like. Communications subsystem 1450 may include one or more input and / or output communication interfaces to permit data to be exchanged with a network such as the network described below to name one example, other computer systems, television, and / or any other devices described herein. Depending on the desired functionality and / or other implementation concerns, a portable electronic device or similar device may communicate an image and / or other information via communications subsystem 1450. In other embodiments, a portable electronic device, e.g., the first electronic device, may be incorporated into AR system 1400, e.g., an electronic device as an input device 1430. In some embodiments, AR system 1400 will further comprise a working memory 1460, which can include a RAM or ROM device, as described above.

[0154] AR system 1400 also can include software elements, shown as being currently located within working memory 1460, including an operating system 1462, device drivers, executable libraries, and / or other code, such as one or more application programs 1464, which may comprise computer programs provided by various embodiments, and / or may be designed to implement methods, and / or configure systems, provided by other embodiments, as described herein. Merely by way of example, one or more procedures described with respect to the methods discussed above might be implemented as code and / or instructionsexecutable by a computer and / or a processor within a computer; in an aspect, then, such code and / or instructions can be used to configure and / or adapt a general purpose computer or other device to perform one or more operations in accordance with the described methods.

[0155] A set of these instructions and / or code may be stored on anon-transitory computer- readable storage medium, such as storage device(s) 1420 described above. In some cases, the storage medium might be incorporated within a computer sy stem, such as AR system 1400. In other embodiments, the storage medium might be separate from a computer system e.g., a removable medium, such as a compact disc, and / or provided in an installation package, such that the storage medium can be used to program, configure, and / or adapt a general purpose computer with the instructions / code stored thereon. These instructions might take the form of executable code, which is executable by AR system 1400 and / or might take the form of source and / or installable code, which, upon compilation and / or installation on AR system 1400, e.g., using any of a variety of generally available compilers, installation programs, compression / decompression utilities, then takes the form of executable code.

[0156] It will be apparent to those skilled in the art that substantial variations may be made in accordance with specific requirements. For example, customized hardware might also be used, and / or particular elements might be implemented in hardware, software including portable software, such as applets, etc., or both. Further, connection to other computing devices such as network input / output devices may be employed.

[0157] As mentioned above, in one aspect, some embodiments may employ a computer system such as AR system 1400 to perform methods in accordance with various embodiments of the technology. According to a set of embodiments, some or all of the procedures of such methods are performed by AR system 1400 in response to one or more processors 1410 executing one or more sequences of one or more instructions, which might be incorporated into operating system 1462 and / or other code, such as an application program 1464. contained in working memory 1460. Such instructions may be read into working memory 1460 from another computer-readable medium, such as one or more of storage device(s) 1420. Merely by way of example, execution of the sequences of instructions contained in working memory71460 might cause one or more processors 1410 to perform one or more procedures of the methods described herein. Additionally or alternatively, portions of the methods described herein may be executed through specialized hardware.

[0158] The terms machine-readable medium and computer-readable medium, as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. In an embodiment implemented using AR system 1400, various computer-readable media might be involved in providing instructions / code to one or more processors 1410 for execution and / or might be used to store and / or carry such instructions / code. In many implementations, a computer-readable medium is a physical and / or tangible storage medium. Such a medium may take the form of a non-volatile media or volatile media. Non-volatile media include, for example, optical and / or magnetic disks, such as storage device(s) 1420. Volatile media include, without limitation, dynamic memory', such as working memory 1460.

[0159] Common forms of physical and / or tangible computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, EPROM, a FLASH-EPROM, any other memory' chip or cartridge, or any other medium from which a computer can read instructions and / or code.

[0160] Various forms of computer-readable media may be involved in carrying one or more sequences of one or more instructions to one or more processors 1410 for execution. Merely by way of example, the instructions may initially be carried on a magnetic disk and / or optical disc of a remote computer. A remote computer might load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and / or executed by AR system 1400.

[0161] Communications subsystem 1450 and / or components thereof generally will receive signals, and bus 1405 then might carry' the signals and / or the data, instructions, etc. carried by the signals to working memory 1460, from which one or more processors 1410 retrieves and executes the instructions. The instructions received by working memory 1460 may optionally be stored on storage device(s) 1420, e.g., a non-transitory' storage device, either before or after execution by one or more processors 1410.

[0162] In the foregoing specification, the disclosure has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of thedisclosure. The specification and drawings are, accordingly, to be regarded in an illustrative rather than restrictive sense.

[0163] Indeed, it will be appreciated that the systems and methods of the disclosure each have several innovative aspects, no single one of which is solely responsible or required for the desirable attributes disclosed herein. The various features and processes described above may be used independently of one another, or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of this disclosure.

[0164] Certain features that are described in this specification in the context of separate embodiments also may be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment also may be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination may in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. No single feature or group of features is necessary or indispensable to each and every embodiment.

[0165] It will be appreciated that conditional language used herein, such as, among others, "can," "could," "might," "may," "e.g.," and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements and / or steps. Thus, such conditional language is not generally intended to imply that features, elements and / or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular embodiment. The terms "comprising." "including," "having," and the like are synonymous and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term "or" is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term "or" means one, some, or all of the elements in the list. In addition, the articles "a," "an," and "the" as used in this application and the appended claims are to be construed to mean "one or more" or "at least one" unless specified otherwise.Similarly, while operations may be depicted in the drawings in a particular order, it is to be recognized that such operations need not be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one or more example processes in the form of a flowchart. However, other operations that are not depicted may be incorporated in the example methods and processes that are schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. Additionally, the operations may be rearranged or reordered in other embodiments. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products. Additionally, other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.

[0166] Accordingly, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with this disclosure, the principles, and the novel features disclosed herein. Thus, it is also understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A head-mounted display system comprising: a projector; a monolithic eyepiece including: an incoupling optical element operable to receive virtual light generated by the projector; a waveguide operable to propagate the virtual light toward left and right portions of the monolithic eyepiece; and left and right light distributing elements operable to output the virtual light toward left and right eyes of a user; and left and right biasing optics operable to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

2. The head-mounted display system of claim 1, wherein: the left and right biasing optics each comprise a first biased lens and a second biased lens; the first biased lens is characterized by a first optical thickness in a first portion of the first biased lens adjacent the projector greater than a second optical thickness in a second portion of the first biased lens distal from the projector; and the second biased lens is characterized by a third optical thickness in a first portion of the second biased lens adjacent the projector less than a second optical thickness in a second portion of the second biased lens distal from the projector.

3. The head-mounted display system of claim 1, wherein the left and right biasing optics each comprise: a rear refractive lens disposed between the monolithic eyepiece and an eye side of the head-mounted display system; and a front refractive lens disposed between the monolithic eyepiece and a world side of the head-mounted display system.

4. The head-mounted display system of claim 3, wherein: the rear refractive lens comprises a negative lens; and the front refractive lens comprises a positive lens.

5. The head-mounted display system of claim 1, wherein the left and right biasing optics each comprise: a rear Fresnel lens disposed between the monolithic eyepiece and an eye side of the head-mounted display system; and a front Fresnel lens disposed between the monolithic eyepiece and a world side of the head-mounted display system.

6. The head-mounted display system of claim 1, wherein the virtual light generated by the projector is simultaneously propagated by the waveguide toward the left and right portions of the monolithic eyepiece.

7. The head-mounted display system of claim 1, wherein the left and right light distributing elements are disposed in the left and right portions of the monolithic eyepiece, respectively.

8. The head-mounted display system of claim 7, wherein the left and right light distributing elements comprise a left diffractive structure with a first optical power biased with respect to the center of the left diffractive structure and a right diffractive structure with a second optical power biased with respect to the center of the right diffractive structure, respectively.

9. The head-mounted display system of claim 1, wherein the monolithic eyepiece is characterized by a curvature.

10. The head-mounted display system of claim 9, wherein the curvature comprises a convex curvature with respect to an eye side of the head-mounted display system.

11. The head-mounted display system of claim 1, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

12. A method of operating a head-mounted display system, the method comprising: generating virtual light by a projector;receiving, by an incoupling optical element of a monolithic eyepiece, the virtual light generated by the projector, wherein the monolithic eyepiece comprises a left light distributing element and a right light distributing element; propagating, by a waveguide of the monolithic eyepiece, the virtual light toward the left light distributing element and the right light distributing element of the monolithic eyepiece; outputting, by left light distributing element and the right light distributing element of the monolithic eyepiece, the virtual light toward a left eye and a right eye of a user, respectively; and angling the virtual light outputted from the left light distributing element and the right light distributing element such that a left virtual light origination point overlaps with a right virtual light origination point.

13. The method of claim 12, wherein angling the virtual light comprises passing the virtual light through a left light biasing optic and a right light biasing optic.

14. The method of claim 12, wherein the monolithic eyepiece is characterized by a curvature.

15. The method of claim 14, wherein the curvature comprises a convex curvature with respect to an eye side of the head-mounted display system.

16. The method of claim 14, wherein angling the virtual light outputted from the left light distributing element and the right light distributing element comprises passing the virtual light through the monolithic eyepiece characterized by the curvature.

17. The method of claim 12, wherein the left light distributing element comprises a left diffractive structure with a first optical power and the right light distributing element comprises a right diffractive structure with a second optical power.

18. The method of claim 17, wherein the first optical power is biased with respect to the center of the left diffractive structure and the second optical power is biased with respect to the center of the right diffractive structure.

19. A head-mounted display system comprising: a projector;a left eyepiece including: a left incoupling optical element operable to receive virtual light generated by the projector; a left waveguide operable to propagate the virtual light; and left light distributing elements operable to output the virtual light toward a left eye of a user; a right eyepiece overlapping and laterally offset from the left eyepiece, the right eyepiece including: a right incoupling optical element operable to receive virtual light generated by the projector; a right waveguide operable to propagate the virtual light; and right light distributing elements operable to output the virtual light toward a right eye of the user; and left and right biasing optics operable to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

20. The head-mounted display system of claim 19, wherein: the left biasing optics comprises: a left rear refractive lens disposed between the left eyepiece and an eye side of the head-mounted display system; and a left front refractive lens disposed between the left eyepiece and a world side of the head-mounted display system; and the right biasing optics comprises: a right rear refractive lens disposed between the right eyepiece and the eye side of the head-mounted display system; and a right front refractive lens disposed between the right eyepiece and the world side of the head-mounted display system.

21. The head-mounted display system of claim 19, wherein: the left biasing optics comprises: a left rear Fresnel lens disposed between the left eyepiece and an eye side of the head-mounted display system; anda left front Fresnel lens disposed between the left eyepiece and a world side of the head-mounted display system; and the right biasing optics comprises: a right rear Fresnel lens disposed between the right eyepiece and the eye side of the head-mounted display system; and a right front Fresnel lens disposed between the right eyepiece and the world side of the head-mounted display system.

22. The head-mounted display system of claim 19, wherein the virtual light generated by the projector is simultaneously propagated by the left waveguide and the right waveguide.

23. The head-mounted display system of claim 19, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

24. The head-mounted display system of claim 19, wherein the left eyepiece and the right eyepiece are tilted with respect to a plane of projection of the headmounted display system.

25. The head-mounted display system of claim 24, wherein the left eyepiece and the right eyepiece are tilted such that the left incoupling optical element and the right incoupling optical element are positioned closer to an eye side of the head-mounted display system.

26. The head-mounted display system of claim 24, wherein the left eyepiece and the right eyepiece are tilted such that the left incoupling optical element and the right incoupling optical element are positioned closer to a world side of the head-mounted display system.

27. The head-mounted display system of claim 19, wherein: the left incoupling optical element operates in a transmissive mode and the right incoupling optical element operates in a reflective mode; or the left incoupling optical element operates in the reflective mode and the right incoupling optical element operates in the transmissive mode.

28. A method of operating a head-mounted display system, the method comprising: generating virtual light by a proj ector; receiving, by a left incoupling optical element of a left eyepiece, the virtual light generated by the projector; propagating the virtual light by a left waveguide of the left eyepiece; outputting, by left light distributing elements of the left eyepiece, the virtual light toward a left eye of a user; receiving, by a right incoupling optical element of a right eyepiece, the virtual light generated by the projector; propagating the virtual light by a right waveguide of the right eyepiece; outputting, by right light distributing elements of the right eyepiece, the virtual light toward a right eye of the user; and angling the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

29. The method of claim 28, wherein the virtual light outputted from the left and right light distributing elements is angled by left and right biasing optics.

30. The method of claim 28, wherein the virtual light outputted from the left and right light distributing elements is angled by a curvature of the left and right eyepieces, wherein the left and right eyepieces are curved in a convex configuration with respect to an eye side of the head-mounted display system.

31. The method of claim 28, wherein the virtual light outputted from the left and right light distributing elements is angled by left and right powered eyepiece elements.

32. A head-mounted display system comprising: a projector; and a monolithic eyepiece including: an incoupling optical element operable to receive virtual light generated by the projector;a waveguide operable to propagate the virtual light toward left and right portions of the monolithic eyepiece; and left and right light distributing elements operable to output the virtual light toward left and right eyes of a user; and wherein the monolithic eyepiece is curved in a convex configuration with respect to an eye side of the head-mounted display system so as to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

33. The head-mounted display system of claim 32, wherein the virtual light generated by the projector is simultaneously propagated by the waveguide toward the left and right portions of the monolithic eyepiece.

34. The head-mounted display system of claim 32, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

35. The head-mounted display system of claim 32, wherein the incoupling optical element operates in a transmissive mode.

36. The head-mounted display system of claim 32, wherein the incoupling optical element operates in a reflective mode.

37. A head-mounted display system comprising: a projector; a left eyepiece including: a left incoupling optical element operable to receive virtual light generated by the projector; a left waveguide operable to propagate the virtual light; and left light distributing elements operable to output the virtual light toward a left eye of a user; and a right eyepiece separate from the left eyepiece, the right eyepiece including: a right incoupling optical element operable to receive virtual light generated by the projector; a right waveguide operable to propagate the virtual light; and right light distributing elements operable to output the virtual light toward a right eye of the user;wherein the left and right eyepieces are curved in a convex configuration with respect to an eye side of the head-mounted display system so as to angle the virtual light outputted from the left and right light distributing elements such that a left virtual light origination point overlaps with a right virtual light origination point.

38. The head-mounted display system of claim 37, wherein the virtual light generated by the projector is simultaneously propagated by the left waveguide and the right waveguide.

39. The head-mounted display system of claim 37, wherein the projector is a Liquid Crystal on Silicon (LCoS) projector.

40. The head-mounted display system of claim 37, wherein: the left incoupling optical element operates in a transmissive mode and the right incoupling optical element operates in a reflective mode: or the left incoupling optical element operates in the reflective mode and the right incoupling optical element operates in the transmissive mode.

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