Augmented reality display having liquid crystal variable focus element, and roll-to-roll method and apparatus for forming the same

Abstract

To provide a favorable augmented reality display having a liquid crystal variable focus element, and a roll-to-roll method and apparatus for forming the same.SOLUTION: A display device includes a waveguide assembly comprising a waveguide configured to outcouple light out of a major surface of the waveguide to form an image in the eyes of a user. An adaptive lens assembly has a major surface facing the output surface, a waveplate lens, and a switchable waveplate assembly. The switchable waveplate assembly includes quarter-wave plates on opposing sides of a switchable liquid crystal layer, and electrodes on the quarter-wave plates in the volume between the quarter-wave plates. The electrodes can selectively establish an electric field and may serve as an alignment structure for molecules of the liquid crystal layer. Portions of the adaptive lens assembly may be manufactured by roll-to-roll processing, in which a substrate roll is unwound and alignment layers and liquid crystal layers are formed on the substrate as it moves towards a second roller so as to be wound on the second roller.SELECTED DRAWING: Figure 16A

Description

[Technical field]

[0001] (Priority Claim) This application claims the benefit of priority to U.S. Provisional Application No. 62 / 577,678, filed October 26, 2017, and entitled "AUGMENTED REALITY DISPLAY HAVING LIQUID CRYSTAL VARIABLE FOCUS ELEMENT AND ROLL-TO-ROLL METHOD AND APPARATUS FOR FORMING THE SAME," the entire contents of which are incorporated herein by reference. (Cited by reference)

[0002] This application is based on the following patent applications: U.S. Patent Application No. 14 / 555,585, filed November 27, 2014, and published on July 23, 2015 as U.S. Patent Publication No. 2015 / 0205126; U.S. Patent Application No. 14 / 690,401, filed April 18, 2015, and published on October 22, 2015 as U.S. Patent Publication No. 2015 / 0302652; U.S. Patent Application No. 14 / 212,961, filed March 14, 2014, and published on August 16, 2016 as U.S. Patent Publication No. 9,417,452; and The present disclosure incorporates by reference in its entirety each of U.S. Patent Application No. 14 / 331,218, filed July 14, 2014, published as U.S. Patent Publication No. 2015 / 0309263 on October 29, 2015, U.S. Patent Application No. 15 / 683,706, filed August 22, 2017, U.S. Provisional Patent Application No. 62 / 424,341, filed November 18, 2016, U.S. Provisional Patent Application No. 62 / 518,539, filed June 12, 2017, and U.S. Patent Application No. 15 / 990,155, filed May 25, 2018.

[0003] The present disclosure relates to display systems, and more particularly to augmented reality display systems. [Background technology]

[0004] Modern computing and display technologies have facilitated the development of systems for so-called "virtual reality" or "augmented reality" experiences, in which digitally reproduced images or portions thereof are presented to a user in a manner that appears or may be perceived as real. Virtual reality or "VR" scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual inputs, while augmented reality or "AR" scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user. Mixed reality or "MR" scenarios are a type of AR scenario that typically involve virtual objects that are integrated into and responsive to the natural world. For example, in MR scenarios, AR image content is perceived to appear occluded by or otherwise interact with objects in the real world.

[0005] 1, an augmented reality scene 10 is depicted in which a user of the AR technology sees a real-world park-like setting 20 featuring people, trees, buildings in the background, and a concrete platform 30. In addition to these items, the user of the AR technology also perceives that they are "seeing" "virtual content," such as a robotic figure 40 standing on the real-world platform 30 and a flying, cartoon-like avatar character 50 that appears to be an anthropomorphic bumblebee, even though these elements 40, 50 do not exist in the real world. The human visual perception system is complex, making it difficult to create AR technology that facilitates a comfortable, natural-feeling, and rich presentation of virtual image elements among other virtual or real-world image elements.

[0006] The systems and methods disclosed herein address various challenges associated with AR or VR technology. Summary of the Invention [Means for solving the problem]

[0007] Details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Neither this summary nor the following detailed description purports to define or limit the scope of the inventive subject matter.

[0008] In a first embodiment, a display device is described. The display device comprises a waveguide assembly comprising a waveguide configured to output light and display an image, and an adaptive lens assembly having a major surface facing the major surface of the waveguide. The adaptive lens assembly comprises a waveplate lens and a switchable waveplate assembly. The switchable waveplate assembly comprises a first non-liquid crystal quarter waveplate and a second non-liquid crystal quarter waveplate defining a volume therebetween, and a liquid crystal layer disposed within the volume between the first and second quarter waveplates, the liquid crystal molecules of the liquid crystal layer having a selectively switchable orientation.

[0009] The switchable waveplate assembly may further comprise an electrode pattern disposed in a volume between the first quarter-wave plate and the second quarter-wave plate, the electrode pattern including a conductive material configured to selectively establish an electric field to change the orientation of the liquid crystal molecules. The electrode pattern may be disposed on the first quarter-wave plate, and another electrode pattern may be disposed in a volume on the second quarter-wave plate. The waveplate lens may comprise a liquid crystal polymer layer. The adaptive lens assembly may further comprise a matching layer disposed between the waveplate lens and the first quarter-wave plate, the matching layer at least partially determining the orientation of the liquid crystal molecules in the liquid crystal polymer layer. The waveplate lens may comprise another liquid crystal polymer layer on the liquid crystal polymer layer. The volume between the first quarter-wave plate and the second quarter-wave plate may further be defined by a cell wall extending between the first quarter-wave plate and the second quarter-wave plate, the cell wall including an inkjet printable material. The waveplate lens and the switchable waveplate assembly may comprise an adaptive lens assembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each comprising a waveplate lens and a switchable waveplate assembly. The display device may further comprise another adaptive lens assembly on an opposite side of the waveguide assembly to the adaptive lens assembly, the other adaptive lens assembly comprising an associated waveplate lens and an associated switchable waveplate assembly.

[0010] In another embodiment, an adaptive lens assembly is described. The adaptive lens assembly comprises a waveplate lens and a switchable waveplate assembly. The switchable waveplate assembly comprises a first non-liquid crystal quarter waveplate, a second non-liquid crystal quarter waveplate defining a volume therebetween, and a liquid crystal layer disposed within the volume between the first and second quarter waveplates, the liquid crystal molecules of the liquid crystal layer having a selectively switchable orientation.

[0011] The switchable waveplate assembly may further comprise an electrode pattern disposed in a volume between the first quarter-wave plate and the second quarter-wave plate, the electrode pattern including a conductive material configured to selectively establish an electric field to change the orientation of the liquid crystal molecules. The electrode pattern may be disposed on the first quarter-wave plate, and another electrode pattern may be disposed in a volume on the second quarter-wave plate. The waveplate lens may comprise a liquid crystal polymer layer. The adaptive lens assembly may further comprise a matching layer disposed between the waveplate lens and the first quarter-wave plate, the matching layer at least partially determining the orientation of the liquid crystal molecules in the liquid crystal polymer layer. The waveplate lens may comprise another liquid crystal polymer layer on the liquid crystal polymer layer. The volume between the first quarter-wave plate and the second quarter-wave plate may further be defined by a cell wall extending between the first quarter-wave plate and the second quarter-wave plate, the cell wall including an inkjet printable material. The waveplate lens and the switchable waveplate assembly may form an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each comprising a waveplate lens and a switchable waveplate assembly.

[0012] In another embodiment, a display device is described. The display device includes a waveguide assembly including a waveguide configured to output light and display an image, and an adaptive lens assembly having a major surface facing a major surface of the waveguide. The adaptive lens assembly includes a waveplate lens and a switchable waveplate assembly. The switchable waveplate assembly includes a first substrate and a second substrate defining a volume therebetween, a liquid crystal layer disposed within the volume, a first set of guides for aligning liquid crystal molecules of the liquid crystal layer, the first set of guides including a first electrode pattern disposed within the volume and on the first substrate, and a second set of guides for aligning liquid crystal molecules of the liquid crystal layer, the second set of guides including a second electrode pattern disposed within the volume and on the first substrate. The first electrode pattern and the second electrode pattern are configured to establish an electric field for selectively changing the orientation of the liquid crystal molecules of the liquid crystal layer.

[0013] At least one of the first and second electrode patterns may comprise an array of parallel conductors. At least one of the first and second electrode patterns may comprise a wire mesh. The first and second substrates may each comprise a quarter wave plate. The wave plate lens and the switchable wave plate assembly may constitute an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising a wave plate lens and a switchable wave plate assembly. The display device may further comprise another adaptive lens assembly on an opposite side of the waveguide assembly to the adaptive lens assembly, the other adaptive lens assembly comprising an associated wave plate lens and an associated switchable wave plate assembly.

[0014] In another embodiment, an adaptive lens assembly is described. The adaptive lens assembly comprises a waveplate lens and a switchable waveplate assembly. The switchable waveplate assembly comprises a first substrate and a second substrate defining a volume therebetween, a liquid crystal layer disposed within the volume, a first set of guides for aligning liquid crystal molecules of the liquid crystal layer, the first set of guides comprising a first electrode pattern disposed within the volume and on the first substrate, and a second set of guides for aligning liquid crystal molecules of the liquid crystal layer, the second set of guides comprising a second electrode pattern disposed within the volume and on the first substrate. The first and second electrode patterns are configured to establish an electric field for selectively changing the orientation of the liquid crystal molecules of the liquid crystal layer.

[0015] At least one of the first and second electrode patterns may comprise an array of parallel conductors. At least one of the first and second electrode patterns may comprise a wire mesh. The first and second substrates may each comprise a quarter wave plate. The wave plate lens may comprise a liquid crystal polymer layer. The adaptive lens assembly may further comprise a matching layer disposed between the wave plate lens and the first quarter wave plate, the matching layer at least partially determining the orientation of the liquid crystal molecules in the liquid crystal polymer layer. The wave plate lens may comprise another liquid crystal polymer layer on the liquid crystal polymer layer. The wave plate lens and the switchable wave plate assembly may constitute an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising a wave plate lens and a switchable wave plate assembly.

[0016] In another embodiment, a roll-to-roll apparatus for manufacturing liquid crystal lenses is described. The apparatus includes a supply substrate roller for providing a roll of substrate for processing, a lens substrate roller for receiving a processed substrate having lens structures thereon, a substrate path defining a path of the unrolled substrate from the supply substrate roller to the lens substrate roller, a first lens layer applicator in the substrate path and configured to form alignment structures for inducing an orientation of liquid crystal molecules on the first side of the substrate, a slot die in the substrate path and configured to apply a first liquid crystal layer to the first side of the supply substrate, and a first curing station configured to cure the first liquid crystal layer.

[0017] The first curing station may comprise an ultraviolet (UV) light source, the UV light source configured to polymerize the liquid crystal molecules of the first liquid crystal layer. The first curing station may comprise a heat source configured to heat the first liquid crystal layer. The roll-to-roll apparatus may further comprise a second lens layer applicator comprising a slot die configured to apply a second liquid crystal layer onto the cured first lens layer and a second curing station configured to cure the second liquid crystal layer. The second curing station may comprise an ultraviolet (UV) light source, the UV light source configured to polymerize the liquid crystal molecules of the second liquid crystal layer. The second curing station may comprise a heat source configured to heat the second liquid crystal layer. The alignment structure applicator may comprise a slot die configured to apply alignment layer resist material to a first side of the supply substrate, a curing station configured to cure the alignment layer resist material to form a solid alignment layer, and an optical aligner configured to optically pattern one or more alignment structures into the solid alignment layer. The alignment structure applicator may include an inkjet printer configured to print a liquid resist material onto a first side of a supply substrate; a roll template configured to imprint the liquid resist material and form a liquid crystal alignment structure; and an energy source configured to harden the liquid resist material while it is in contact with the conformal roll template and form a solid resist comprising the pattern of the alignment structure on the first side of the supply substrate.

[0018] In another embodiment, a roll-to-roll apparatus for manufacturing liquid crystal lenses is described, the apparatus comprising a supply substrate roller for providing a roll of substrate for processing, an intermediate substrate roller for receiving the processed substrate having alignment structures thereon, a substrate path defining a path of the unfolded substrate from the supply substrate roller to the intermediate substrate roller, a deposition device configured to deposit an imprint resist, a continuous template loop configured to advance along a closed template path defined by the plurality of rollers (the imprinted portion of the template path coincides with a portion of the substrate path), and an energy source configured to harden the alignment structures and form a solid alignment layer.

[0019] The energy source may comprise an ultraviolet (UV) light source. The deposition device may comprise a slot die upstream of the energy source and configured to apply the imprint resist to the first side of the feed substrate, and the template loop may be configured to imprint the imprint resist along the imprint portion of the roll template path. The deposition device may comprise an inkjet printer upstream of the energy source and configured to print the imprint resist, and the template is configured to imprint the imprint resist along the imprint portion of the template path. The inkjet printer may be configured to deposit the imprint resist on the template.

[0020] In another embodiment, a method for manufacturing a liquid crystal lens is described, the method comprising the steps of unrolling a supply roll of substrate on a supply substrate roller, processing the unrolled substrate extending between the supply substrate roller and the lens substrate roller, and subsequently rewinding the unrolled substrate on the lens substrate roller, the processing of the unrolled substrate comprising forming a matching layer on a first side of the unrolled substrate, depositing a first liquid crystal layer over the matching structure, and curing the first liquid crystal layer to form a first lens layer.

[0021] Depositing the first liquid crystal layer may include applying the liquid crystal onto the alignment structures using a slot die. Curing the first liquid crystal layer may include irradiating the first liquid crystal layer with ultraviolet (UV) light. Curing the first liquid crystal layer may include heating the first liquid crystal layer in an oven. Forming the alignment layer may include depositing a selectively definable material on the first side of the substrate and patterning the deposited selectively definable material. Patterning the selectively definable material may include exposing the selectively definable material to light to form a holographic recording. The selectively definable material may be a resist, and patterning the selectively definable material includes imprinting the resist using a conformal roll template and curing the liquid resist material while the liquid resist material is in contact with the conformal roll template to form a solid alignment structure on the first side of the supply substrate. The method may further include applying a second liquid crystal layer over the first lens layer and curing the second liquid crystal layer to form a solid second lens layer. The method may further include forming an electrode pattern on a bottom side of the substrate opposite the side on which the matching layer is formed before unrolling the supply roll. The method may further include unrolling the substrate after rewinding the unrolled substrate and forming a plurality of liquid crystal cell walls on the bottom side of the substrate. The forming the plurality of liquid crystal cell walls may include inkjet deposition. The method may further include attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate, and the liquid crystal cell walls, and filling the open volume with liquid crystal. The substrate may be a quarter wave plate.

[0022] In another embodiment, a method for manufacturing a liquid crystal lens is described, the method comprising the steps of unrolling a supply roll of substrate on a supply substrate roller, the unrolled substrate extending between the supply substrate roller and an intermediate substrate roller, forming alignment features on the unrolled substrate to guide orientation of liquid crystal molecules on the substrate, the forming of the alignment features comprising imprinting the alignment features using a closed-loop template having a travel path defined by a plurality of rollers, and subsequently rewinding the unrolled substrate on the intermediate substrate roller.

[0023] The step of forming the alignment features may include depositing an imprint resist on the substrate, imprinting the imprint resist using the template, and curing the imprint resist while the template imprints the imprint resist to form solid alignment structures on the supply substrate. The supply roll may include an electrode pattern on a lower side of the substrate opposite to the upper side on which the alignment layer is to be formed. The method may further include unfolding the substrate after rewinding the unfolded substrate and forming a plurality of liquid crystal cell walls on the upper side of the substrate. The step of forming a plurality of liquid crystal cell walls may include printing the cell walls by inkjet deposition. The method may further include attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate, and the liquid crystal cell walls, and filling the open volume with liquid crystal. The substrate may be a quarter wave plate.

[0024] In another embodiment, a method for manufacturing a liquid crystal lens is described. The method includes the steps of unrolling a roll of an intermediate substrate on an intermediate substrate roller, the intermediate substrate comprising alignment features for liquid crystal molecules, the alignment features being on a first side of the intermediate substrate, processing the unrolled substrate extending between the intermediate substrate roller and the lens substrate roller, and subsequently rewinding the unrolled substrate on the lens substrate roller. Processing the unrolled substrate includes depositing a first liquid crystal layer on the alignment features and curing the first liquid crystal layer to form a first lens layer.

[0025] The step of depositing the first liquid crystal layer may include applying the liquid crystal material using a slot die. The step of curing the first liquid crystal layer may include irradiating the first liquid crystal layer with ultraviolet (UV) light. The step of curing the first liquid crystal layer may include heating the first liquid crystal layer in an oven. The method may further include applying a second liquid crystal layer over the first lens layer and curing the second liquid crystal layer to form a solid second lens layer. The method may further include unrolling the unrolled substrate after rerolling the substrate and forming a plurality of liquid crystal cell walls on the substrate. The step of forming a plurality of liquid crystal cell walls may include inkjet deposition. The method may further include attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate, and the liquid crystal cell walls, and filling the open volume with liquid crystal material. The substrate may be a quarter wave plate with alignment features thereon. The present specification also provides, for example, the following items: (Item 1) 1. A display device, comprising: a waveguide assembly, the waveguide assembly comprising a waveguide configured to output light and display an image; an adaptive lens assembly having a major surface facing a major surface of the waveguide, the adaptive lens assembly comprising: A wave plate lens; 1. A switchable waveplate assembly comprising: a first non-liquid crystal quarter wave plate and a second non-liquid crystal quarter wave plate defining a volume therebetween; a liquid crystal layer disposed within a volume between the first quarter wave plate and the second quarter wave plate, liquid crystal molecules of the liquid crystal layer having a selectively switchable orientation; a switchable waveplate assembly comprising: an adaptive lens assembly comprising: A display device comprising: (Item 2) 2. The display device of claim 1, wherein the switchable waveplate assembly further comprises an electrode pattern disposed within a volume between the first quarter-waveplate and the second quarter-waveplate, the electrode pattern comprising a conductive material configured to selectively establish an electric field to change the orientation of the liquid crystal molecules. (Item 3) 3. The display device of claim 2, wherein the electrode pattern is disposed on the first quarter-wave plate and another electrode pattern is disposed within a volume above the second quarter-wave plate. (Item 4) Item 2. The display device of item 1, wherein the waveplate lens comprises a liquid crystal polymer layer. (Item 5) 5. The display device of claim 4, wherein the adaptive lens assembly further comprises an alignment layer disposed between the wave plate lens and the first quarter wave plate, the alignment layer at least partially determining an orientation of liquid crystal molecules within the liquid crystal polymer layer. (Item 6) 5. The display device of claim 4, wherein the waveplate lens comprises another liquid crystal polymer layer on the liquid crystal polymer layer. (Item 7) 2. The display device of claim 1, wherein a volume between the first quarter-wave plate and the second quarter-wave plate is further defined by a cell wall extending between the first quarter-wave plate and the second quarter-wave plate, the cell wall comprising an inkjet printable material. (Item 8) The waveplate lens and the switchable waveplate assembly form an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising: A wave plate lens; A switchable waveplate assembly 2. The display device of item 1, comprising: (Item 9) 2. The display device of claim 1, further comprising another adaptive lens assembly on an opposite side of the waveguide assembly to the adaptive lens assembly, the other adaptive lens assembly comprising an associated wave plate lens and an associated switchable wave plate assembly. (Item 10) 1. An adaptive lens assembly, comprising: A wave plate lens; 1. A switchable waveplate assembly comprising: a first non-liquid crystal quarter wave plate and a second non-liquid crystal quarter wave plate defining a volume therebetween; a liquid crystal layer disposed within a volume between the first quarter wave plate and the second quarter wave plate, liquid crystal molecules of the liquid crystal layer having a selectively switchable orientation; a switchable waveplate assembly comprising: An adaptive lens assembly comprising: (Item 11) Item 11. The display device of item 10, wherein the switchable waveplate assembly further comprises an electrode pattern disposed within a volume between the first quarter-waveplate and the second quarter-waveplate, the electrode pattern including a conductive material configured to selectively establish an electric field to change the orientation of the liquid crystal molecules. (Item 12) Item 12. The display device of item 11, wherein the electrode pattern is disposed on the first quarter-wave plate and another electrode pattern is disposed within a volume above the second quarter-wave plate. (Item 13) Item 11. The display device of item 10, wherein the waveplate lens comprises a liquid crystal polymer layer. (Item 14) Item 14. The display device of item 13, wherein the adaptive lens assembly further comprises an alignment layer disposed between the wave plate lens and the first quarter wave plate, the alignment layer at least in part determining an orientation of liquid crystal molecules within the liquid crystal polymer layer. (Item 15) Item 14. The display device of item 13, wherein the waveplate lens comprises another liquid crystal polymer layer on the liquid crystal polymer layer. (Item 16) Item 11. The display device of item 10, wherein a volume between the first quarter-wave plate and the second quarter-wave plate is further defined by a cell wall extending between the first quarter-wave plate and the second quarter-wave plate, the cell wall comprising an inkjet printable material. (Item 17) The waveplate lens and the switchable waveplate assembly form an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising: A wave plate lens; A switchable waveplate assembly Item 11. A display device according to item 10, comprising: (Item 18) 1. A display device, comprising: a waveguide assembly, the waveguide assembly comprising a waveguide configured to output light and display an image; an adaptive lens assembly having a major surface facing a major surface of the waveguide, the adaptive lens assembly comprising: A wave plate lens; 1. A switchable waveplate assembly comprising: a first substrate and a second substrate defining a volume therebetween; a liquid crystal layer disposed within the volume; a first set of guides for aligning liquid crystal molecules of the liquid crystal layer, the first set of guides being disposed within the volume and comprising a first electrode pattern on the first substrate; a second set of guides for aligning liquid crystal molecules of the liquid crystal layer, the second set of guides being disposed within the volume and comprising a second electrode pattern on the first substrate; and Equipped with a switchable waveplate assembly, the first electrode pattern and the second electrode pattern being configured to establish an electric field for selectively changing an orientation of liquid crystal molecules of the liquid crystal layer; an adaptive lens assembly comprising: A display device comprising: (Item 19) Item 19. The display device of item 18, wherein at least one of the first electrode pattern and the second electrode pattern comprises an array of parallel conductors. (Item 20) Item 19. The display device of item 18, wherein at least one of the first electrode pattern and the second electrode pattern comprises a wire mesh. (Item 21) Item 19. The display device of item 18, wherein the first substrate and the second substrate each comprise a quarter wave plate. (Item 22) The waveplate lens and the switchable waveplate assembly form an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising: A wave plate lens; A switchable waveplate assembly 20. The display device of item 18, comprising: (Item 23) Item 19. The display device of item 18, further comprising another adaptive lens assembly on an opposite side of the waveguide assembly to the adaptive lens assembly, the other adaptive lens assembly comprising an associated wave plate lens and an associated switchable wave plate assembly. (Item 24) 1. An adaptive lens assembly, comprising: A wave plate lens; 1. A switchable waveplate assembly comprising: a first substrate and a second substrate defining a volume therebetween; a liquid crystal layer disposed within the volume; a first set of guides for aligning liquid crystal molecules of the liquid crystal layer, the first set of guides being disposed within the volume and comprising a first electrode pattern on the first substrate; a second set of guides for aligning liquid crystal molecules of the liquid crystal layer, the second set of guides being disposed within the volume and comprising a second electrode pattern on the first substrate; and Equipped with a switchable waveplate assembly, the first electrode pattern and the second electrode pattern being configured to establish an electric field for selectively changing an orientation of liquid crystal molecules of the liquid crystal layer; An adaptive lens assembly comprising: (Item 25) Item 25. The adaptive lens assembly of item 24, wherein at least one of the first electrode pattern and the second electrode pattern comprises an array of parallel conductors. (Item 26) Item 25. The adaptive lens assembly of item 24, wherein at least one of the first electrode pattern and the second electrode pattern comprises a wire mesh. (Item 27) Item 25. The display device of item 24, wherein the first substrate and the second substrate each comprise a quarter wave plate. (Item 28) Item 25. The display device of item 24, wherein the waveplate lens comprises a liquid crystal polymer layer. (Item 29) 30. The display device of claim 28, wherein the adaptive lens assembly further comprises an alignment layer disposed between the wave plate lens and the first quarter wave plate, the alignment layer at least in part determining an orientation of liquid crystal molecules within the liquid crystal polymer layer. (Item 30) Item 29. The display device of item 28, wherein the waveplate lens comprises another liquid crystal polymer layer on the liquid crystal polymer layer. (Item 31) The waveplate lens and the switchable waveplate assembly form an adaptive lens subassembly, the adaptive lens assembly comprising a plurality of adaptive lens subassemblies, each adaptive lens subassembly comprising: A wave plate lens; A switchable waveplate assembly 25. The display device of item 24, comprising: (Item 32) 1. A roll-to-roll apparatus for manufacturing a liquid crystal lens, the apparatus comprising: a supply substrate roller for providing a roll of substrate for processing; a lens substrate roller for receiving thereon a processed substrate having a lens structure; a substrate path defining a path of an unfolded substrate from the supply substrate roller to the lens substrate roller; an alignment structure applicator in the substrate path, the alignment structure applicator configured to form alignment structures for inducing an orientation of liquid crystal molecules on a first side of the substrate; a first lens layer applicator in the substrate path, the first lens layer applicator comprising: a slot die configured to apply a first liquid crystal layer to a first side of the donor substrate; a first curing station configured to cure the first liquid crystal layer; a first lens layer applicator comprising: An apparatus comprising: (Item 33) Item 33. The roll-to-roll apparatus of item 32, wherein the first curing station comprises an ultraviolet (UV) light source, the UV light source configured to polymerize liquid crystal molecules of the first liquid crystal layer. (Item 34) Item 33. The roll-to-roll apparatus of item 32, wherein the first curing station comprises a heat source configured to heat the first liquid crystal layer. (Item 35) a second lens layer applicator, a slot die configured to apply a second liquid crystal layer onto the cured first lens layer; a second curing station configured to cure the second liquid crystal layer; A second lens layer applicator comprising: Item 33. The roll-to-roll apparatus of item 32, further comprising: (Item 36) Item 36. The roll-to-roll apparatus of item 35, wherein the second curing station comprises an ultraviolet (UV) light source, the UV light source configured to polymerize liquid crystal molecules of the second liquid crystal layer. (Item 37) Item 36. The roll-to-roll apparatus of item 35, wherein the second curing station comprises a heat source configured to heat the second liquid crystal layer. (Item 38) The alignment structure applicator comprises: a slot die configured to apply a matching layer resist material to a first side of the feed substrate; a curing station configured to harden the matching layer resist material to form a solid matching layer; an optical aligner configured to optically pattern one or more alignment structures in the solid alignment layer; Item 33. The roll-to-roll apparatus of item 32, comprising: (Item 39) The alignment structure applicator comprises: an inkjet printer configured to print a liquid resist material onto a first side of the supply substrate; a roll template configured to imprint the liquid resist material to form a liquid crystal alignment structure; an energy source configured to harden the liquid resist material while the liquid resist material is in contact with the conformal roll template to form a solid resist comprising a pattern of alignment structures on a first side of the supply substrate; Item 33. The roll-to-roll apparatus of item 32, comprising: (Item 40) 1. A roll-to-roll apparatus for manufacturing a liquid crystal lens, the apparatus comprising: a supply substrate roller for providing a roll of substrate for processing; an intermediate substrate roller for receiving a processed substrate having alignment structures thereon; a substrate path defining a path of an unfolded substrate from the supply substrate roller to the intermediate substrate roller; a deposition device configured to deposit an imprint resist; a continuous template loop configured to travel along a closed template path defined by a plurality of rollers, an imprint portion of the template path coinciding with a portion of the substrate path; an energy source configured to cure the alignment structure to form a solid alignment layer; An apparatus comprising: (Item 41) Item 41. The roll-to-roll apparatus of item 40, wherein the energy source comprises an ultraviolet (UV) light source. (Item 42) Item 41. The roll-to-roll apparatus of item 40, wherein the deposition device comprises a slot die upstream of the energy source, the slot die configured to apply the imprint resist to a first side of the supply substrate, and the template loop configured to imprint the imprint resist along an imprint portion of the roll template path. (Item 43) Item 41. The roll-to-roll apparatus of item 40, wherein the deposition device comprises an inkjet printer upstream of the energy source, the inkjet printer configured to print an imprint resist, and the template configured to imprint the imprint resist along an imprint portion of the template path. (Item 44) Item 44. The roll-to-roll apparatus of item 43, wherein the inkjet printer is configured to deposit the imprint resist onto the template. (Item 45) 1. A method for manufacturing a liquid crystal lens, the method comprising: unrolling a supply roll of substrate at a supply substrate roller; processing a spread substrate extending between the supply substrate roller and a lens substrate roller; Next, the unrolled substrate is re-wound on the lens substrate roller. and processing the unfolded substrate comprises: forming a matching layer on a first side of the unfolded substrate; depositing a first liquid crystal layer over the alignment structure; curing the first liquid crystal layer to form a first lens layer; A method comprising: (Item 46) Item 46. The method of item 45, wherein depositing the first liquid crystal layer comprises applying liquid crystal onto the alignment structure using a slot die. (Item 47) Item 46. The method of item 45, wherein curing the first liquid crystal layer comprises irradiating the first liquid crystal layer with ultraviolet (UV) light. (Item 48) Item 46. The method of item 45, wherein curing the first liquid crystal layer comprises heating the first liquid crystal layer in an oven. (Item 49) forming the matching layer depositing a selectively definable material on a first side of the substrate; patterning the deposited selectively definable material; and Item 46. The method according to item 45, comprising: (Item 50) 50. The method of claim 49, wherein patterning the selectively definable material comprises exposing the selectively definable material to light to form a holographic recording. (Item 51) The selectively definable material is a resist, and patterning the selectively definable material comprises: imprinting the resist using a conformal roll template; hardening the liquid resist material while the liquid resist material is in contact with the conformal roll template to form a solid alignment structure on the first side of the supply substrate; 50. The method according to item 49, comprising: (Item 52) applying a second liquid crystal layer over the first lens layer; curing the second liquid crystal layer to form a solid second lens layer. Item 46. The method of item 45, further comprising: (Item 53) Item 46. The method of item 45, further comprising forming an electrode pattern on a bottom side of the substrate opposite to the side on which the matching layer is formed, prior to unfolding the donor roll. (Item 54) Item 54. The method of item 53, further comprising unrolling the unrolled substrate and forming a plurality of liquid crystal cell walls on the underside of the substrate. (Item 55) Item 55. The method of item 54, wherein forming the plurality of liquid crystal cell walls comprises inkjet deposition. (Item 56) attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate and the liquid crystal cell wall; filling said open volume with liquid crystal; 55. The method of claim 54, further comprising: (Item 57) Item 46. The method of item 45, wherein the substrate is a quarter wave plate. (Item 58) 1. A method for manufacturing a liquid crystal lens, the method comprising: unrolling a supply roll of substrate at a supply substrate roller, the unrolled substrate extending between the supply substrate roller and an intermediate substrate roller; forming alignment features on the developed substrate to guide orientation of liquid crystal molecules on the substrate, the forming of the alignment features including imprinting the alignment features using a closed-loop template having a travel path defined by a plurality of rollers; Next, the unrolled substrate is re-wound on the intermediate substrate roller. A method comprising: (Item 59) forming the alignment feature depositing an imprint resist onto the substrate; imprinting the imprint resist using the template; curing the imprint resist while the template imprints the imprint resist to form a solid alignment structure on the supply substrate. 59. The method according to claim 58, comprising: (Item 60) Item 59. The method of item 58, wherein the supply roll comprises an electrode pattern on a lower side of the substrate opposite an upper side on which the matching layer is to be formed. (Item 61) Item 61. The method of item 60, further comprising unrolling the unrolled substrate and forming a plurality of liquid crystal cell walls on the top side of the substrate after unrolling the unrolled substrate. (Item 62) Item 62. The method of item 61, wherein forming the plurality of liquid crystal cell walls comprises printing the cell walls by inkjet deposition. (Item 63) attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate and the liquid crystal cell wall; filling said open volume with liquid crystal; Item 62. The method of item 61, further comprising: (Item 64) Item 59. The method of item 58, wherein the substrate is a quarter wave plate. (Item 65) 1. A method for manufacturing a liquid crystal lens, the method comprising: unrolling a roll of intermediate substrate on an intermediate substrate roller, the intermediate substrate comprising alignment features for liquid crystal molecules, the alignment features being on a first side of the intermediate substrate; Processing a spread-out substrate extending between the intermediate substrate roller and the lens substrate roller, the processing of the spread-out substrate comprising: depositing a first liquid crystal layer over the alignment features; curing the first liquid crystal layer to form a first lens layer; and Next, the unrolled substrate is re-wound on the lens substrate roller. A method comprising: (Item 66) Item 66. The method of item 65, wherein depositing the first liquid crystal layer comprises applying the liquid crystal material using a slot die. (Item 67) Item 66. The method of item 65, wherein curing the first liquid crystal layer comprises irradiating the first liquid crystal layer with ultraviolet (UV) light. (Item 68) Item 66. The method of item 65, wherein curing the first liquid crystal layer comprises heating the first liquid crystal layer in an oven. (Item 69) applying a second liquid crystal layer over the first lens layer; curing the second liquid crystal layer to form a solid second lens layer. Item 66. The method of item 65, further comprising: (Item 70) Item 66. The method of item 65, further comprising unrolling the unrolled substrate and forming a plurality of liquid crystal cell walls on the substrate. (Item 71) Item 71. The method of item 70, wherein forming the plurality of liquid crystal cell walls comprises inkjet deposition. (Item 72) attaching the substrate to another substrate to form an open volume defined by the substrate, the other substrate and the liquid crystal cell wall; filling said open volume with a liquid crystal material; 71. The method of claim 70, further comprising: (Item 73) Item 46. The method of item 45, wherein the substrate is a quarter wave plate having the alignment features thereon. [Brief description of the drawings]

[0026] [Figure 1] FIG. 1 illustrates a user's view of an augmented reality (AR) device.

[0027] [Diagram 2] FIG. 2 illustrates a conventional display system for simulating a three-dimensional image for a user.

[0028] [Diagram 3] 3A-3C illustrate the relationship between the radius of curvature and the radius of focus.

[0029] [Figure 4A]FIG. 4A illustrates a representation of the accommodation-vergence response of the human visual system.

[0030] [Figure 4B] FIG. 4B illustrates examples of different accommodation and convergence states of a pair of eyes of a user.

[0031] [Figure 4C] FIG. 4C illustrates an example of a top-down view representation of a user viewing content through a display system.

[0032] [Figure 4D] FIG. 4D illustrates another example of a top-down view representation of a user viewing content through a display system.

[0033] [Diagram 5] FIG. 5 illustrates aspects of an approach for simulating a three-dimensional image by modifying wavefront divergence.

[0034] [Figure 6] FIG. 6 illustrates an embodiment of a waveguide stack for outputting image information to a user.

[0035] [Figure 7] FIG. 7 illustrates an example of an output beam output by a waveguide.

[0036] [Figure 8] FIG. 8 illustrates an example of a stacked waveguide assembly where each depth plane contains an image formed using multiple different primary colors.

[0037] [Figure 9A] FIG. 9A illustrates a cross-sectional side view of an example of a set of stacked waveguides, each of which includes an internal coupling optical element.

[0038] [Figure 9B] FIG. 9B illustrates a perspective view of the multiple stacked waveguide embodiment of FIG. 9A.

[0039] [Figure 9C] FIG. 9C illustrates a top-down plan view of the multiple stacked waveguide embodiment of FIGS. 9A and 9B.

[0040] [Figure 9D] FIG. 9D illustrates an example of a wearable display system.

[0041] [Figure 10] FIG. 10 illustrates an example of a display system including a pair of adaptive lens assemblies.

[0042] [Figure 11] Figure 11A illustrates an embodiment of the display system of Figure 10 that displays virtual content to a user in a virtual depth plane, and Figure 11B illustrates an embodiment of the display system of Figure 10 that provides a user with a view of real-world content.

[0043] [Figure 12] FIG. 12 illustrates an example of a display device comprising a pair of adaptive lens assemblies, each comprising an alternating stack of waveplate lenses and a switchable waveplate.

[0044] [Figure 13A] 13A and 13B illustrate an example of a display device comprising a pair of adaptive lens assemblies and a pair of fixed lenses. [Figure 13B] 13A and 13B illustrate an example of a display device comprising a pair of adaptive lens assemblies and a pair of fixed lenses.

[0045] [Figure 14]FIG. 14 illustrates an example of a display device comprising a pair of adaptive lens assemblies and a fixed lens.

[0046] [Figure 15] FIG. 15 illustrates an exemplary adaptive lens assembly comprising three adaptive lens layers.

[0047] [Figure 16A] 16A and 16B each illustrate a further example adaptive lens assembly comprising three adaptive lens layers. [Figure 16B] 16A and 16B each illustrate a further example adaptive lens assembly comprising three adaptive lens layers.

[0048] [Figure 17A] 17A-17E illustrate an exemplary process for manufacturing an adaptive lens assembly. [Figure 17B] 17A-17E illustrate an exemplary process for manufacturing an adaptive lens assembly. [Figure 17C] 17A-17E illustrate an exemplary process for manufacturing an adaptive lens assembly. [Figure 17D] 17A-17E illustrate an exemplary process for manufacturing an adaptive lens assembly. [Figure 17E] 17A-17E illustrate an exemplary process for manufacturing an adaptive lens assembly.

[0049] [Figure 18A] FIG. 18A illustrates an exemplary apparatus for roll-to-roll manufacturing of lens substrates with optical alignment processes for adaptive lens assemblies.

[0050] [Figure 18B] 18B-C illustrate an exemplary apparatus for roll-to-roll manufacturing of lens substrates using an imprint alignment process for adaptive lens assemblies. [Figure 18C] 18B-C illustrate an exemplary apparatus for roll-to-roll manufacturing of lens substrates using an imprint alignment process for adaptive lens assemblies.

[0051] [Figure 18D] FIG. 18D illustrates an exemplary apparatus for roll-to-roll manufacturing of intermediate substrates using an imprint alignment process for adaptive lens assemblies.

[0052] [Figure 18E] FIG. 18E illustrates an exemplary apparatus for roll-to-roll manufacturing of lens substrates using intermediate substrates produced by the apparatus of FIG. 18D.

[0053] [Figure 19A] FIG. 19A illustrates an exemplary apparatus for sheet manufacturing of lens substrates using an imprint alignment process for adaptive lens assemblies.

[0054] [Figure 19B] FIG. 19B illustrates an exemplary apparatus for sheet manufacturing of lens substrates using an optical alignment process for adaptive lens assemblies.

[0055] [Figure 20A] FIG. 20A illustrates an exemplary apparatus for spin-coat manufacturing of lens substrates using an imprint alignment process for adaptive lens assemblies.

[0056] [Figure 20B] FIG. 20B illustrates an exemplary apparatus for spin-coat manufacturing of lens substrates with optical alignment processes for adaptive lens assemblies.

[0057] [Figure 21] 21A-21C illustrate an embodiment of a process for forming a pattern of conductive material by directional etching.

[0058] [Figure 22] 22A-22C illustrate an example process for forming a pattern of conductive material using a solvent dissolvable layer.

[0059] [Figure 23] 23A-23C illustrate an embodiment of a process for forming a pattern of conductive material using a seed layer.

[0060] [Figure 24] 24A-24C illustrate another embodiment of a process for forming a pattern of conductive material using a seed layer.

[0061] [Diagram 25] 25A-25C illustrate an example of a process for forming a pattern of conductive material by deposition of a suspension of metallic material into openings in a patterned layer.

[0062] [Figure 26] 26A-26F illustrate examples of top-down views of patterns of conductive material.

[0063] [Figure 27] 27A-27D illustrate examples of cross-sectional side views of lines of conductive material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] The AR system may display virtual content to a user or viewer while still allowing the user to see the world around them. Preferably, this content is displayed on a head-mounted display, e.g., as part of eyewear, that projects image information to the user's eyes. In addition, the display may also transmit light from the surrounding environment to the user's eyes, allowing a view of the surrounding environment. As used herein, it should be understood that a "head-mounted" or "head-mountable" display is a display that can be mounted on the viewer's or user's head.

[0065] In some AR systems, the multiple waveguides may be configured to form virtual images at multiple virtual depth planes (also referred to simply herein as "depth planes"). Different waveguides of the multiple waveguides may have different refractive powers, which may provide images that appear on different depth planes at different distances from the user's eyes. The display system may also include multiple lenses that provide or modify the refractive power of the waveguides. Undesirably, the waveguides and lenses may each increase the overall thickness and weight of the display.

[0066] Adaptive lens assemblies, which may also be referred to as variable focus lens assemblies, have been proposed in an approach to reduce the thickness and weight of displays. The adaptive lens assemblies provide variable refractive power, e.g., modify the wavefront divergence of light propagating through the lens assembly, and provide multiple different virtual depth planes. For example, rather than multiple waveguides, a single adaptive lens assembly may be utilized to provide different sets of refractive powers and associated depth planes. Examples of adaptive lens assemblies and related structures are disclosed in U.S. Provisional Patent Application No. 62 / 424,341, filed November 18, 2016, and U.S. Provisional Patent Application No. 62 / 518,539, filed June 12, 2017, the entire disclosures of each of which are incorporated herein by reference.

[0067] The adaptive lens assembly may include a stack of adaptive lens subassemblies, each of which may include a waveplate lens and a switchable waveplate assembly, which may include a liquid crystal layer with liquid crystal molecules switchable between different states having different orientations. The switchable waveplate assembly may include a pair of substrates for confining the liquid crystal layer, an alignment layer for establishing the orientation of the liquid crystal molecules in the liquid crystal layer, and a conductive layer for providing an electric field and switching the orientation of the liquid crystal molecules. It should be understood that each adaptive lens subassembly may affect the wavefront of light passing therethrough differently depending on the state of the switchable waveplate. The refractive powers of multiple subassemblies may be combined to provide different aggregate refractive powers. However, it has been found that an adaptive lens assembly with a large number of such subassemblies may still be thicker than desired.

[0068] Advantageously, in some embodiments, a thin adaptive lens assembly and methods and apparatus for making such an assembly are provided. In some embodiments, the switchable waveplate assembly may include a pair of substrates that are themselves waveplates (e.g., quarter waveplates) with a switchable waveplate (preferably a liquid crystal layer having liquid crystal molecules with selectively switchable orientation) disposed between them. Preferably, the substrates do not comprise liquid crystal. In some other embodiments, the switchable waveplate assembly may include a pattern of electrodes that act both as alignment guides for the liquid crystal molecules and as a conductive layer that selectively establishes an electric field to switch the orientation of the liquid crystal molecules. In some embodiments, the electrode pattern may be disposed on the surface of the substrate that also functions as a waveplate. For example, the electrodes may be on opposing faces of the substrates and disposed within the same volume between the substrates occupied by the liquid crystal layer. It should be understood that the electrodes may be freestanding on the surface of the substrate or may be embedded in a layer of other material.

[0069] Advantageously, the thin switchable waveplate assembly may form an adaptive lens subassembly with a passive waveplate lens that does not include liquid crystal molecules that change orientation with the application of an electric field as described above. It should be understood that the switchable waveplate assembly and the passive waveplate lens can modify the polarization of light and thus provide refractive power. The passive waveplate lens may be formed from polymerized liquid crystal molecules locked into a specific pattern and / or orientation. The specific pattern and / or orientation may provide a desired optical response only in a narrow wavelength range of light. In some embodiments, multiple waveplate lenses may be provided to provide a broader band response over a wider wavelength range. Each waveplate lens may have a peak response over a different wavelength range, and collectively, the waveplate lens provides a response over a wider wavelength range.

[0070] As described herein, multiple subassemblies may be stacked together to form an adaptive lens assembly that provides a range of optical powers. In some other embodiments, the adaptive lens assembly may include only a single subassembly.

[0071] In some embodiments, the adaptive lens assembly or a portion thereof may be manufactured using a roll-to-roll manufacturing apparatus. A substrate forming part of a volume containing a switchable liquid crystal layer may be used as the substrate on which adjacent layers are formed, and then the pair of substrates may be joined together to form a volume that is subsequently filled with the switchable liquid crystal. The substrate is preferably formed from a flexible, mechanically stable, optically transparent material that can be rolled up and unrolled during the manufacturing process. For example, a supply of substrate may be provided on a first roller and extended onto a second roller. The substrate is unrolled on the first roller and then rerolled on the second roller. In the meantime, a matching layer may be deposited and patterned on the substrate, and one or more liquid crystal layers may be deposited and cured on the matching layer. Preferably, the substrate provided on the first roller may include a preformed pattern of electrodes on the back surface of the substrate.

[0072] In some embodiments, the fabrication of the matching layer may be performed using a first roll-to-roll machine, in which a substrate roll is unrolled and an imprinted matching layer (with matching features for liquid crystal molecules) is formed on the substrate, which is rewound after forming the imprinted matching layer, followed by a second roll-to-roll manufacturing machine using the substrate with the imprinted matching layer with matching features as a starting material, depositing a liquid crystal layer on the substrate, and then rewound the substrate with the deposited liquid crystal layer.

[0073] In some embodiments, after roll-to-roll processing, the processed substrate sheet, with the electrodes on one side of the sheet and the deposited layers on the other side, may be joined with another substrate sheet, with the electrodes on the surface of the sheet. Before joining the substrate sheets together, walls may be formed on one or both sheets to laterally confine the subsequent liquid crystal filling. The walls may be in the desired shape for the display eyepiece. The sheets may then be joined together with the electrodes facing each other, forming an open volume. The open volume may then be filled with liquid crystal, and the sheets may then be cut to form individual display eyepieces. In some other embodiments, liquid crystal may be provided within the volume defined by the walls and the lower substrate, and then the upper substrate may be bonded to the walls to form a closed volume.

[0074] Advantageously, in some embodiments, the adaptive lens assemblies described herein may be of thin and / or lightweight construction. For example, an adaptive lens assembly having three adaptive lens subassemblies may have a relatively thin thickness (e.g., less than 2 mm in some embodiments). By having a quarter wave plate serve both as an optical element in the adaptive lens subassembly and as a support substrate, an additional support substrate may not be required. Furthermore, an array of meshes or wires on a surface of the quarter wave plate proximate to the liquid crystal layer may be arranged to serve both as a potential source and as an alignment structure to induce alignment of liquid crystal molecules in the liquid crystal layer. Additionally, the disclosed roll-to-roll manufacturing apparatus and methods enable efficient high-throughput manufacturing of adaptive lens assemblies.

[0075] Reference is now made to the drawings, in which like reference numbers refer to like parts throughout, and in which, unless otherwise indicated, the drawings are schematic and are not necessarily drawn to scale.

[0076] FIG. 2 illustrates a conventional display system for simulating a three-dimensional image for a user. It should be understood that when a user's eyes are spaced apart and viewing a real object in space, each eye may have a slightly different view of the object and form an image of the object at a different location on each eye's retina. This may be referred to as binocular disparity and may be exploited by the human visual system to provide a perception of depth. Conventional display systems simulate binocular disparity by presenting two distinctly different images 190, 200 with slightly different views of the same virtual object, one for each eye 210, 220, corresponding to the view of the virtual object as it would appear by each eye as if the virtual object were a real object at a desired depth. These images provide binocular cues that the user's visual system may interpret to derive a perception of depth.

[0077] Continuing with reference to FIG. 2, the images 190, 200 are spaced from the eyes 210, 220 by a distance 230 on the z-axis, which is parallel to the optical axis of the viewer when that eye is fixating on an object at optical infinity directly in front of the viewer. The images 190, 200 are flat and at a fixed distance from the eyes 210, 220. Based on slightly different views of the virtual object in the images presented to the eyes 210, 220, respectively, the eyes may necessarily rotate such that the image of the object falls on a corresponding point on the eye's respective retina to maintain single binocular vision. This rotation may cause the line of sight of each of the eyes 210, 220 to converge on a point in space where the virtual object is perceived to reside. As a result, providing three-dimensional images traditionally involves manipulating the convergence and divergence movements of the user's eyes 210, 220 to provide binocular cues that the human visual system interprets to provide the perception of depth.

[0078] However, creating a realistic and comfortable perception of depth is difficult. It should be understood that light from an object at different distances from the eye has a wavefront with different amounts of divergence. Figures 3A-3C illustrate the relationship between distance and divergence of light rays. The distance between the object and the eye 210 is represented in the order of decreasing distances R1, R2, and R3. As shown in Figures 3A-3C, the light rays become more divergent as the distance to the object decreases. Conversely, as the distance increases, the light rays become more collimated. In other words, the light field generated by a point (an object or part of an object) can be said to have a spherical wavefront curvature that is a function of the distance the point is away from the user's eye. As the curvature increases, the distance between the object and the eye 210 decreases. Although only a single eye 210 is illustrated in Figures 3A-3C and various other figures herein for clarity of illustration, the discussion regarding the eye 210 may apply to both eyes 210 and 220 of a viewer.

[0079] 3A-3C, light from an object that a viewer's eye is fixating on may have different wavefront divergences. Due to the different wavefront divergences, the light may be focused differently by the eye's lens, which in turn may require the lens to assume a different shape and form a focused image on the eye's retina. If a focused image is not formed on the retina, the resulting retinal blur acts as an accommodative cue, causing the shape of the eye's lens to change until a focused image is formed on the retina. For example, an accommodative cue may induce relaxation or contraction of the ciliary muscle surrounding the eye's lens, thereby modulating the force applied to the suspensory ligament that holds the lens, thus changing the shape of the eye's lens, thereby forming a focused image of the fixated object on the eye's retina (e.g., the fovea) until retinal blur of the fixated object is eliminated or minimized. The process by which the eye lens changes shape may be referred to as accommodation, and the shape of the eye lens required to form a focused image of a fixated object on the eye's retina (e.g., the fovea) may be referred to as the state of accommodation.

[0080] Referring now to FIG. 4A, a representation of the accommodation-vergence response of the human visual system is illustrated. A movement of the eye to fixate an object causes the eye to receive light from the object, which forms an image on each of the eye's retinas. The presence of retinal blur in the image formed on the retina may provide a cue for accommodation, and the relative location of the image on the retina may provide a cue for vergence. A cue for accommodation causes accommodation, resulting in the eye's lens adopting a particular accommodation state in which each of the eyes' lenses forms a focused image of the object on the eye's retina (e.g., the fovea). On the other hand, a cue for vergence causes a vergence movement (eye rotation) such that the image formed on each retina of each eye is at a corresponding retinal point that maintains single binocular vision. In these positions, the eyes may be said to adopt a particular vergence state. Continuing with reference to FIG. 4A, accommodation can be understood to be the process by which the eye achieves a particular accommodation state, and convergence can be understood to be the process by which the eye achieves a particular convergence state. As shown in FIG. 4A, the accommodation and convergence state of the eye can change when the user fixates a different object. For example, the accommodated state can change when the user fixates a new object at a different depth on the z-axis.

[0081] Without being limited by theory, it is believed that a viewer of an object may perceive the object as being "three-dimensional" due to a combination of vergence-divergence and accommodation. As previously mentioned, vergence-divergence movements of the two eyes relative to one another (e.g., rotation of the eyes such that the pupils move toward or away from one another, converging the gaze of the eyes to fixate on an object) are closely linked to accommodation of the eye's lenses. Under normal conditions, changing the shape of the eye's lenses and shifting focus from one object to another at a different distance will automatically produce a matching change in vergence to the same distance, a relationship known as the "accommodation-vergence-divergence reflex." Similarly, a change in vergence will induce a matching change in lens shape under normal conditions.

[0082] 4B, an example of different accommodation and convergence states of the eyes is illustrated. The pair of eyes 222a fixates an object at optical infinity, while the pair of eyes 222b fixates an object 221 at less than optical infinity. Notably, the convergence states of each pair of eyes are different, with the pair of eyes 222a pointing straight ahead, while the pair of eyes 222 converge on the object 221. The accommodation states of the eyes forming each pair of eyes 222a and 222b are also different, as represented by the different shapes of the lenses 210a, 220a.

[0083] Unfortunately, many users of conventional "3-D" display systems may find such conventional systems uncomfortable or may not perceive any depth sensation due to a mismatch between accommodation and vergence states in these displays. As previously mentioned, many stereoscopic or "3-D" display systems display a scene by providing a slightly different image to each eye. Such systems are uncomfortable for many viewers because, among other things, they simply provide a different presentation of the scene, causing changes in the vergence states of the eyes, but without a corresponding change in the accommodation states of those eyes. Rather, images are presented by the display at a fixed distance from the eyes, such that the eyes view all image information in a single accommodation state. Such an arrangement counters the "accommodation-vergence-divergence reflex" by causing changes in vergence states without a matching change in accommodation state. This mismatch is believed to cause viewer discomfort. By providing better matching between accommodation and convergence-divergence movements, display systems may form a more realistic and comfortable simulation of three-dimensional images.

[0084] Without being limited by theory, it is believed that the human eye is typically capable of interpreting a finite number of depth planes to provide depth perception. As a result, a highly realistic simulation of perceived depth may be achieved by providing the eye with different presentations of images corresponding to each of these limited number of depth planes. In some embodiments, the different presentations may provide both vergence cues and matching cues for accommodation, thereby providing physiologically correct accommodation-vergence divergence matching.

[0085] 4B, two depth planes 240 are illustrated, corresponding to different distances in space from the eyes 210, 220. For a given depth plane 240, vergence-divergence cues may be provided by displaying appropriately different perspective images for each eye 210, 220. Additionally, for a given depth plane 240, the light forming the image provided to each eye 210, 220 may have a wavefront divergence corresponding to the light field generated by a point at the distance of that depth plane 240.

[0086] In the illustrated embodiment, the distance along the z-axis of the depth plane 240 containing the point 221 is 1 m. As used herein, the distance or depth along the z-axis may be measured with the zero point located at the exit pupil of the user's eye. Thus, the depth plane 240 located at a depth of 1 m corresponds to a distance of 1 m away from the exit pupil of the user's eye on the optical axis of the eye with the eye pointed towards optical infinity. As an approximation, the depth or distance along the z-axis may be measured from the display (e.g., the surface of the waveguide) in front of the user's eye, and a value for the distance between the device and the exit pupil of the user's eye may be added. That value may be called the pupil distance and may correspond to the distance between the exit pupil of the user's eye and the display worn by the user in front of the eye. In practice, the value for the pupil distance may be a normalized value that is generally used for all viewers. For example, the pupil distance may be assumed to be 20 mm, and the depth plane at a depth of 1 m may be at a distance of 980 mm in front of the display.

[0087] 4C and 4D, examples of matched accommodation-vergence-divergence distances and mismatched accommodation-vergence-divergence distances are illustrated, respectively. As illustrated in FIG. 4C, the display system may provide an image of a virtual object to each eye 210, 220. The image may cause the eyes 210, 220 to assume a convergence-divergence state in which the eyes converge on point 15 on the depth plane 240. In addition, the image may be formed by light having a wavefront curvature corresponding to a real object in that depth plane 240. As a result, the eyes 210, 220 assume an accommodation state in which the image is focused on the retinas of those eyes. Thus, the user may perceive the virtual object as being at point 15 on the depth plane 240.

[0088] It should be appreciated that each of the accommodation and convergence states of the eyes 210, 220 is associated with a particular distance on the z-axis. For example, an object at a particular distance from the eyes 210, 220 will cause those eyes to assume a particular accommodation state based on the distance of the object. The distance associated with a particular accommodation state is referred to as the accommodation distance A. d Similarly, a particular convergence-divergence distance V associated with the eyes in a particular convergence-divergence state may be referred to as d or positions relative to each other. When the accommodation distance and the vergence distance match, the relationship between accommodation and vergence is said to be physiologically correct. This is considered to be the most comfortable scenario for the viewer.

[0089] However, in a stereoscopic display, the accommodation distance and the vergence distance may not always match. For example, as illustrated in FIG. 4D, the images displayed to the eyes 210, 220 may be displayed with a wavefront divergence corresponding to the depth plane 240, and the eyes 210, 220 may be in a particular accommodation state in which the points 15a, 15b on the depth plane are in focus. However, the images displayed to the eyes 210, 220 may provide a cue for vergence that causes the eyes 210, 220 to converge on a point 15 that is not located on the depth plane 240. As a result, the accommodation distance corresponds in some embodiments to the distance from the exit pupils of the eyes 210, 220 to the depth plane 240, while the vergence distance corresponds to a larger distance from the exit pupils of the eyes 210, 220 to the point 15. The accommodation distance is different from the vergence distance. As a result, there is an accommodation-vergence-divergence mismatch. Such a mismatch may be considered undesirable and may cause discomfort to the user. The mismatch may be related to distance (e.g., V d -A d ) and can be characterized in terms of diopters.

[0090] It should be understood that in some embodiments, reference points other than the exit pupils of the eyes 210, 220 may be utilized to determine distances for determining accommodation-vergence-divergence mismatch, so long as the same reference points are utilized for accommodation distance and vergence-divergence distance. For example, distances may be measured from the cornea to the depth plane, from the retina to the depth plane, from the eyepiece (e.g., a waveguide in a display device) to the depth plane, etc.

[0091] Without being limited by theory, it is believed that a user may still perceive an accommodation-vergence-divergence mismatch of up to about 0.25 diopters, up to about 0.33 diopters, and up to about 0.5 diopters as physiologically correct, without the mismatch itself causing significant discomfort. In some embodiments, a display system disclosed herein (e.g., display system 250, FIG. 6) presents an image to a viewer having an accommodation-vergence-divergence mismatch of about 0.5 diopters or less. In some other embodiments, the accommodation-vergence-divergence mismatch of the image provided by the display system is about 0.33 diopters or less. In still other embodiments, the accommodation-vergence-divergence mismatch of the image provided by the display system is about 0.25 diopters or less, including about 0.1 diopters or less.

[0092] FIG. 5 illustrates aspects of an approach for simulating a three-dimensional image by modifying wavefront divergence. The display system includes a waveguide 270 configured to receive light 770 encoded with image information and output the light to a user's eye 210. The waveguide 270 may output light 650 with a defined amount of wavefront divergence that corresponds to the wavefront divergence of a light field generated by a point on a desired depth plane 240. In some embodiments, the same amount of wavefront divergence is provided for all objects presented on that depth plane. In addition, the user's other eye will be illustrated as being provided with image information from a similar waveguide.

[0093] In some embodiments, a single waveguide may be configured to output light with a set wavefront divergence corresponding to a single or limited number of depth planes, and / or the waveguide may be configured to output light of a limited range of wavelengths. As a result, in some embodiments, multiple or stacked waveguides may be utilized to provide different wavefront divergence for different depth planes and / or output light of different ranges of wavelengths. As used herein, it should be understood that a depth plane may follow the contour of a flat or curved surface. In some embodiments, advantageously, for simplicity, a depth plane may follow the contour of a flat surface.

[0094] 6 illustrates an example of a waveguide stack for outputting image information to a user. The display system 250 includes a stack of waveguides or a stacked waveguide assembly 260 that can be utilized to provide a three-dimensional perception to the eye / brain using multiple waveguides 270, 280, 290, 300, 310. It should be understood that the display system 250 may be considered a light field display in some embodiments. Additionally, the waveguide assembly 260 may also be referred to as an eyepiece.

[0095] In some embodiments, the display system 250 may be configured to provide a substantially continuous cue for convergence and multiple discrete cues for accommodation. The cues for convergence may be provided by displaying different images to each of the user's eyes, and the cues for accommodation may be provided by outputting light forming images with selectable discrete amounts of wavefront divergence. In other words, the display system 250 may be configured to output light with variable levels of wavefront divergence. In some embodiments, each discrete level of wavefront divergence corresponds to a particular depth plane and may be provided by a particular one of the waveguides 270, 280, 290, 300, 310.

[0096] Continuing with reference to FIG. 6, the waveguide assembly 260 may also include a number of features 320, 330, 340, 350 between the waveguides. In some embodiments, the features 320, 330, 340, 350 may be one or more lenses. The waveguides 270, 280, 290, 300, 310 and / or the number of lenses 320, 330, 340, 350 may be configured to transmit image information to the eye with various levels of wavefront curvature or light beam divergence. Each waveguide level may be associated with a particular depth plane and may be configured to output image information corresponding to that depth plane. The image input devices 360, 370, 380, 390, 400 may act as light sources for the waveguides and may be utilized to input image information into the waveguides 270, 280, 290, 300, 310, each of which may be configured to disperse incident light across each individual waveguide for output towards the eye 210, as described herein. Light exits output surfaces 410, 420, 430, 440, 450 of the image input devices 360, 370, 380, 390, 400 and is input into corresponding input surfaces 460, 470, 480, 490, 500 of the waveguides 270, 280, 290, 300, 310. In some embodiments, each of the input surfaces 460, 470, 480, 490, 500 may be an edge of the corresponding waveguide or may be a portion of the major surface of the corresponding waveguide (i.e., one of the waveguide surfaces that directly faces the world 510 or the viewer's eye 210). In some embodiments, a single beam of light (e.g., a collimated beam) may be launched into each waveguide, outputting a total field of cloned collimated beams that are directed towards the eye 210 at a particular angle (and divergence) corresponding to the depth plane associated with the particular waveguide. In some embodiments, a single one of the image launch devices 360, 370, 380, 390, 400 may be associated with and launch light into multiple (e.g., three) waveguides 270, 280, 290, 300, 310.

[0097] In some embodiments, each of the image input devices 360, 370, 380, 390, 400 is a discrete display that generates image information for input into the respective waveguides 270, 280, 290, 300, 310. In some other embodiments, the image input devices 360, 370, 380, 390, 400 are the output of a single multiplexed display that may, for example, send image information to each of the image input devices 360, 370, 380, 390, 400 via one or more optical conduits (such as fiber optic cables). It should be understood that the image information provided by the image input devices 360, 370, 380, 390, 400 may include light of different wavelengths or colors (e.g., different primary colors as discussed herein).

[0098] In some embodiments, the light injected into the waveguides 270, 280, 290, 300, 310 is provided by a light projector system 520, which includes a light module 530, which may include a light emitter such as a light emitting diode (LED). The light from the light module 530 may be directed and modified by a light modulator 540, e.g., a spatial light modulator, via a beam splitter 550. The light modulator 540 may be configured to vary the perceived intensity of the light injected into the waveguides 270, 280, 290, 300, 310 and encode the light with image information. Examples of spatial light modulators include liquid crystal displays (LCDs), including liquid crystal on silicon (LCOS) displays. It should be understood that image injection devices 360, 370, 380, 390, 400 are illustrated diagrammatically and in some embodiments these image injection devices may represent light paths and locations within a common projection system configured to output light into associated ones of waveguides 270, 280, 290, 300, 310. In some embodiments, the waveguides of the waveguide assembly 260 may act as ideal lenses, relaying light injected into the waveguides to the user's eye. In this concept, the object may be a spatial light modulator 540 and the image may be an image on a depth plane.

[0099] In some embodiments, the display system 250 may be a scanning fiber display comprising one or more scanning fibers configured to project light in various patterns (e.g., raster scan, spiral scan, Lissajous pattern, etc.) into one or more waveguides 270, 280, 290, 300, 310 and ultimately to the viewer's eye 210. In some embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may diagrammatically represent a single scanning fiber or a bundle of scanning fibers configured to inject light into one or more waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may diagrammatically represent multiple scanning fibers or multiple bundles of scanning fibers, each configured to inject light into an associated one of the waveguides 270, 280, 290, 300, 310. It should be understood that one or more optical fibers may be configured to transmit light from the optical module 530 to one or more of the waveguides 270, 280, 290, 300, 310. It should be understood that one or more intervening optical structures may be provided between the scanning fiber or fibers and one or more of the waveguides 270, 280, 290, 300, 310, for example, to redirect light exiting the scanning fiber into one or more of the waveguides 270, 280, 290, 300, 310.

[0100] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image input devices 360, 370, 380, 390, 400, the light source 530, and the light modulator 540. In some embodiments, the controller 560 is part of the local data processing module 140. The controller 560 includes programming (e.g., instructions in a non-transient medium) that coordinates the timing and provisioning of image information to the waveguides 270, 280, 290, 300, 310, for example, according to any of the various schemes disclosed herein. In some embodiments, the controller may be a single integrated device or a distributed system connected by wired or wireless communication channels. The controller 560 may be part of the processing module 140 or 150 (FIG. 9D) in some embodiments.

[0101] Continuing with reference to FIG. 6, the waveguides 270, 280, 290, 300, 310 may be configured to propagate light within each individual waveguide by total internal reflection (TIR). Each of the waveguides 270, 280, 290, 300, 310 may be planar or have another shape (e.g., curved) with major top and bottom surfaces and edges extending between the major top and bottom surfaces. In the illustrated configuration, each of the waveguides 270, 280, 290, 300, 310 may include an outcoupling optical element 570, 580, 590, 600, 610 configured to extract light from the waveguide by redirecting light propagating within each individual waveguide out of the waveguide and outputting image information to the eye 210. The extracted light may also be referred to as outcoupling light, and the outcoupling optical element light may also be referred to as a light extraction optical element. The extracted beam of light may be output by the waveguide at a location where the light propagating within the waveguide strikes the light extraction optical element. The outcoupling optical element 570, 580, 590, 600, 610 may be a grating, for example, including diffractive optical features as further discussed herein. Although shown disposed on the bottom major surface of the waveguide 270, 280, 290, 300, 310 for ease of explanation and clarity of the drawings, in some embodiments the outcoupling optical element 570, 580, 590, 600, 610 may be disposed on the top and / or bottom major surfaces and / or directly within the volume of the waveguide 270, 280, 290, 300, 310, as further discussed herein. In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 may be formed within a layer of material that is attached to a transparent substrate and forms the waveguide 270, 280, 290, 300, 310. In some other embodiments, the waveguide 270, 280, 290, 300, 310 may be a monolithic piece of material and the outcoupling optical elements 570, 580, 590, 600, 610 may be formed on a surface of and / or within that piece of material.

[0102] With continued reference to FIG. 6, as discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to output light and form an image corresponding to a particular depth plane. For example, the waveguide 270 closest to the eye may be configured to deliver collimated light (injected into such waveguide 270) to the eye 210. The collimated light may represent an optical infinity focal plane. The next upper waveguide 280 may be configured to send collimated light that passes through a first lens 350 (e.g., a negative lens) before it can reach the eye 210. Such first lens 350 may be configured to generate a slight convex wavefront curvature such that the eye / brain interprets the light originating from the next upper waveguide 280 as originating from a first focal plane closer inward from optical infinity toward the eye 210. Similarly, the third upper waveguide 290 passes its output light through both the first lens 350 and the second lens 340 before reaching the eye 210. The combined refractive powers of the first lens 350 and the second lens 340 may be configured to produce another incremental amount of wavefront curvature such that the eye / brain interprets the light emerging from the third waveguide 290 as emerging from a second focal plane that is closer inward from optical infinity towards the person than was the light from the next upper waveguide 280.

[0103] The other waveguide layers 300, 310 and lenses 330, 320 are similarly configured, with the highest waveguide 310 in the stack sending its output through all of the lenses between it and the eye for an aggregate focal power that represents the focal plane closest to the person. To compensate the stack of lenses 320, 330, 340, 350 when viewing / interpreting light originating from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 may be placed on top of the stack to compensate for the aggregate power of the lens stacks 320, 330, 340, 350 below. Such a configuration provides as many perceived focal planes as there are waveguide / lens pairs available. Both the outcoupling optical elements of the waveguides and the focusing sides of the lenses may be static (i.e., not dynamic or electroactive). In some alternative embodiments, one or both may be dynamic using electroactive features.

[0104] In some embodiments, two or more of the waveguides 270, 280, 290, 300, 310 may have the same associated depth plane. For example, multiple waveguides 270, 280, 290, 300, 310 may be configured to output images set at the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output images set at the same depth planes, with one set per depth plane. This may provide the advantage of forming tiled images to provide an extended field of view at those depth planes.

[0105] Continuing with reference to FIG. 6, the outcoupling optical elements 570, 580, 590, 600, 610 may be configured to redirect light from its respective waveguide and output the light with an appropriate amount of divergence or collimation for a particular depth plane associated with the waveguide. As a result, waveguides with different associated depth planes may have different configurations of outcoupling optical elements 570, 580, 590, 600, 610 that output light with different amounts of divergence depending on the associated depth plane. In some embodiments, the light extraction optical elements 570, 580, 590, 600, 610 may be volume or surface features that may be configured to output light at specific angles. For example, the light extraction optical elements 570, 580, 590, 600, 610 may be volume holograms, surface holograms, and / or diffraction gratings. In some embodiments, features 320, 330, 340, 350 may not be lenses. Rather, they may simply be spacers (e.g., cladding layers and / or structures for forming air gaps).

[0106] In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 are diffractive features or "diffractive optical elements" (also referred to herein as "DOEs") that form a diffraction pattern. Preferably, the DOEs have a sufficiently low diffraction efficiency such that only a portion of the light in the beam is deflected toward the eye 210 at each intersection of the DOE, while the remainder continues to travel through the waveguide via TIR. The light carrying the image information is thus split into several related exit beams that exit the waveguide at various locations, resulting in a very uniform pattern of exit emission toward the eye 210 for this particular collimated beam bouncing within the waveguide.

[0107] In some embodiments, one or more DOEs may be switchable between an "on" state in which they actively diffract and an "off" state in which they do not significantly diffract. For example, a switchable DOE may comprise a layer of polymer dispersed liquid crystal in which microdroplets comprise a diffractive pattern in a host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not significantly diffract incident light), or the microdroplets may be switched to a refractive index that does not match that of the host medium (in which case the pattern actively diffracts incident light).

[0108] In some embodiments, a camera assembly 630 (e.g., a digital camera, including visible and infrared light cameras) may be provided to capture images of the eye 210 and / or tissue surrounding the eye 210, for example, to detect user input and / or monitor a physiological condition of the user. As used herein, a camera may be any image capture device. In some embodiments, the camera assembly 630 may include an image capture device and a light source that projects light (e.g., infrared light) onto the eye, which may then be reflected by the eye and detected by the image capture device. In some embodiments, the camera assembly 630 may be mounted to the frame 80 (FIG. 9D) and may be in electrical communication with the processing modules 140 and / or 150, which may process image information from the camera assembly 630. In some embodiments, one camera assembly 630 may be utilized per eye, monitoring each eye separately.

[0109] 7, an example of an output beam output by a waveguide is shown. Although one waveguide is shown, it should be understood that other waveguides in the waveguide assembly 260 (FIG. 6) may function similarly and that the waveguide assembly 260 includes multiple waveguides. Light 640 is launched into the waveguide 270 at the input surface 460 of the waveguide 270 and propagates within the waveguide 270 by TIR. At the point where the light 640 impinges on the DOE 570, a portion of the light exits the waveguide as an output beam 650. The output beam 650 is shown as approximately parallel, but may be redirected to propagate to the eye 210 at an angle (e.g., divergent output beam formation) as discussed herein and depending on the depth plane associated with the waveguide 270. It should be understood that a nearly collimated exit beam may refer to a waveguide with outcoupling optics that outcouples light to form an image that appears to be set at a depth plane at a large distance (e.g., optical infinity) from the eye 210. Other waveguides or other sets of outcoupling optics may output an exit beam pattern that is more divergent, which would require the eye 210 to accommodate to a closer distance and focus on the retina, and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

[0110] In some embodiments, a full color image may be formed at each depth plane by overlaying an image on each of the primary colors, for example, three or more primary colors. FIG. 8 illustrates an example of a stacked waveguide assembly, where each depth plane includes an image formed using multiple different primary colors. The illustrated embodiment shows depth planes 240a-240f, but more or less depths are also contemplated. Each depth plane may have three or more primary color images associated with it, including a first image of a first color G, a second image of a second color R, and a third image of a third color B. The different depth planes are indicated in the diagram by different numbers for diopters (dpt) following the letters G, R, and B. Merely by way of example, the numbers following each of these letters indicate the diopters (1 / m), i.e., the inverse distance of the depth plane from the viewer, and each box in the diagram represents an individual primary color image. In some embodiments, the exact locations of the depth planes for the different primary colors may be varied to account for differences in the eye's focusing of light of different wavelengths. For example, different primary color images for a given depth plane may be placed on depth planes that correspond to different distances from the user. Such an arrangement may increase visual acuity and user comfort, and / or reduce chromatic aberration.

[0111] In some embodiments, the light of each primary color may be output by a single dedicated waveguide, such that each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figure containing the letter G, R, or B may be understood to represent an individual waveguide, and three waveguides may be provided per depth plane, with three primary color images provided per depth plane. The waveguides associated with each depth plane are shown adjacent to each other in this drawing for ease of illustration, but it should be understood that in a physical device, the waveguides may all be arranged in a stack with one waveguide per level. In some other embodiments, multiple primary colors may be output by the same waveguide, such that, for example, only a single waveguide may be provided per depth plane.

[0112] 8, in some embodiments, G is green, R is red, and B is blue. In some other embodiments, other colors associated with other wavelengths of light, including magenta and cyan, may be used in addition to or in place of one or more of the red, green, or blue colors.

[0113] It should be understood that references throughout this disclosure to a given color of light will be understood to encompass light of one or more wavelengths within the range of wavelengths of light that are perceived by a viewer to be of that given color. For example, red light may include one or more wavelengths of light within a range of about 620-780 nm, green light may include one or more wavelengths of light within a range of about 492-577 nm, and blue light may include one or more wavelengths of light within a range of about 435-493 nm.

[0114] In some embodiments, the light source 530 (FIG. 6) may be configured to emit light at one or more wavelengths outside the range of visual perception of a viewer, e.g., infrared and / or ultraviolet wavelengths. Additionally, the waveguide in-coupling, out-coupling, and other light redirecting structures of the display 250 may be configured to direct and emit this light from the display toward the user's eye 210, e.g., for imaging and / or user stimulation applications.

[0115] 9A, in some embodiments, light impinging on a waveguide may need to be redirected to in-couple the light into the waveguide. An in-coupling optical element may be used to redirect and in-couple the light into its corresponding waveguide. FIG. 9A illustrates a cross-sectional side view of an example of a plurality or set 660 of stacked waveguides, each including an in-coupling optical element. Each of the waveguides may be configured to output light of one or more different wavelengths or one or more different wavelength ranges. The stack 660 may correspond to the stack 260 (FIG. 6), and the illustrated waveguides of the stack 660 may correspond to a portion of the plurality of waveguides 270, 280, 290, 300, 310, although it should be understood that light from one or more of the image input devices 360, 370, 380, 390, 400 is launched into the waveguide from a position that requires the light to be redirected for in-coupling.

[0116] The illustrated set 660 of stacked waveguides includes waveguides 670, 680, and 690. Each waveguide includes an associated incoupling optical element (which may also be referred to as the light input area on the waveguide), for example, incoupling optical element 700 is disposed on a major surface (e.g., the top major surface) of waveguide 670, incoupling optical element 710 is disposed on a major surface (e.g., the top major surface) of waveguide 680, and incoupling optical element 720 is disposed on a major surface (e.g., the top major surface) of waveguide 690. In some embodiments, one or more of the incoupling optical elements 700, 710, 720 may be disposed on a bottom major surface of an individual waveguide 670, 680, 690 (particularly, one or more of the incoupling optical elements are reflective polarizing optical elements). As shown, the incoupling optical elements 700, 710, 720 may be disposed on the upper major surface of the respective waveguide 670, 680, 690 (or on top of the next lower waveguide), and in particular, the incoupling optical elements are transmissive deflecting optical elements. In some embodiments, the incoupling optical elements 700, 710, 720 may be disposed within the body of the respective waveguide 670, 680, 690. In some embodiments, as discussed herein, the incoupling optical elements 700, 710, 720 are wavelength selective such that they selectively redirect one or more wavelengths of light while transmitting other wavelengths of light. Although illustrated on one side or corner of the respective waveguide 670, 680, 690, it should be understood that the incoupling optical elements 700, 710, 720 may be disposed within other areas of the respective waveguide 670, 680, 690 in some embodiments.

[0117] As shown, the in-coupling optical elements 700, 710, 720 may be laterally offset from one another. In some embodiments, each in-coupling optical element may be offset to receive light without that light passing through another in-coupling optical element. For example, each in-coupling optical element 700, 710, 720 may be configured to receive light from different image input devices 360, 370, 380, 390, and 400 as shown in FIG. 6 and may be separated (e.g., laterally spaced) from the other in-coupling optical elements 700, 710, 720 so as to not substantially receive light from others of the in-coupling optical elements 700, 710, 720.

[0118] Each waveguide also includes an associated optically dispersive element, for example, optically dispersive element 730 is disposed on a major surface (e.g., the top major surface) of waveguide 670, optically dispersive element 740 is disposed on a major surface (e.g., the top major surface) of waveguide 680, and optically dispersive element 750 is disposed on a major surface (e.g., the top major surface) of waveguide 690. In some other embodiments, optically dispersive elements 730, 740, 750 may be disposed on the bottom major surfaces of the associated waveguides 670, 680, 690, respectively. In some other embodiments, the optically dispersive elements 730, 740, 750 may be disposed on both the top and bottom major surfaces of the associated waveguides 670, 680, 690, respectively, or the optically dispersive elements 730, 740, 750 may be disposed on different ones of the top and bottom major surfaces in different associated waveguides 670, 680, 690, respectively.

[0119] The waveguides 670, 680, 690 may be spaced apart and separated by, for example, gas, liquid, and / or solid layers of material. For example, as shown, layer 760a may separate the waveguides 670 and 680, and layer 760b may separate the waveguides 680 and 690. In some embodiments, layers 760a and 760b are formed from a low index material (i.e., a material having a lower index of refraction than the material forming the immediate neighbors of the waveguides 670, 680, 690). Preferably, the index of refraction of the material forming layers 760a, 760b is 0.05 or greater, or 0.10 or less, relative to the index of refraction of the material forming the waveguides 670, 680, 690. Advantageously, the lower refractive index layers 760a, 760b may act as cladding layers to promote total internal reflection (TIR) ​​of light through the waveguides 670, 680, 690 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some embodiments, the layers 760a, 760b are formed from air. Although not shown, it should be understood that the top and bottom of the illustrated set of waveguides 660 may include immediate cladding layers.

[0120] Preferably, for ease of manufacturing and other considerations, the materials forming the waveguides 670, 680, 690 are similar or the same, and the materials forming the layers 760a, 760b are similar or the same. In some embodiments, the materials forming the waveguides 670, 680, 690 may differ between one or more of the waveguides, and / or the materials forming the layers 760a, 760b may differ while still maintaining the various refractive index relationships discussed above.

[0121] 9A, light rays 770, 780, 790 are incident on the set of waveguides 660. It should be understood that light rays 770, 780, 790 may be injected into the waveguides 670, 680, 690 by one or more image injection devices 360, 370, 380, 390, 400 (FIG. 6).

[0122] In some embodiments, the light beams 770, 780, 790 have different properties, e.g., different wavelengths or different wavelength ranges, that may correspond to different colors. Each of the incoupling optical elements 700, 710, 720 deflects the incident light such that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR. In some embodiments, each of the incoupling optical elements 700, 710, 720 selectively deflects one or more particular wavelengths of light while transmitting other wavelengths to the underlying waveguide and associated incoupling optical element.

[0123] For example, incoupling optical element 700 may be configured to selectively deflect light beam 770 having a first wavelength or wavelength range while transmitting light beams 780 and 790 having different second and third wavelengths or wavelength ranges, respectively. Transmitted light beam 780 impinges on and is deflected by incoupling optical element 710, which is configured to selectively deflect light of the second wavelength or wavelength range. Light beam 790 is deflected by incoupling optical element 720, which is configured to selectively deflect light of the third wavelength or wavelength range.

[0124] 9A, the deflected light rays 770, 780, 790 are deflected to propagate through the corresponding waveguides 670, 680, 690. That is, the incoupling optical element 700, 710, 720 of each waveguide deflects the light into its corresponding waveguide 670, 680, 690 and incouplings the light into the corresponding waveguide. The light rays 770, 780, 790 are deflected at an angle that causes the light to propagate through the respective waveguides 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the respective waveguides 670, 680, 690 by TIR until they impinge on the corresponding optical dispersive element 730, 740, 750 of the waveguide.

[0125] 9B, a perspective view of the multiple stacked waveguide embodiment of FIG. 9A is illustrated. As previously described, the in-coupled light rays 770, 780, 790 are deflected by the in-coupling optical elements 700, 710, 720, respectively, and then propagate by TIR within the waveguides 670, 680, 690, respectively. The light rays 770, 780, 790 then impinge on the optically dispersive elements 730, 740, 750, respectively. The optically dispersive elements 730, 740, 750 deflect the light rays 770, 780, 790 to propagate towards the out-coupling optical elements 800, 810, 820, respectively.

[0126] In some embodiments, the optically dispersive elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or disperse the light to the out-coupling optical elements 800, 810, 820, and in some embodiments may also increase the beam or spot size of this light as it propagates to the out-coupling optical elements. In some embodiments, the optically dispersive elements 730, 740, 750 may be omitted and the in-coupling optical elements 700, 710, 720 may be configured to deflect the light directly to the out-coupling optical elements 800, 810, 820. For example, referring to FIG. 9A, the optically dispersive elements 730, 740, 750 may be replaced with the out-coupling optical elements 800, 810, 820, respectively. In some embodiments, the outcoupling optical elements 800, 810, 820 are exit pupils (EPs) or exit pupil expanders (EPEs) that direct light to the viewer's eye 210 (FIG. 7). It should be understood that the OPEs may be configured to increase the size of the eyebox in at least one axis, and the EPEs may increase the eyebox in an axis that intersects, e.g., orthogonal to, the axis of the OPE. 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 propagating down the waveguide. In response to striking the OPE, again, another portion of the remaining light is redirected to the EPE, which continues to propagate further down the waveguide, etc. Similarly, in response to striking the EPE, a portion of the striking light is directed out of the waveguide towards the user, and the remaining portion of the light continues to propagate through the waveguide until it strikes the EP again, at which point another portion of the striking light is directed out of the waveguide, etc. As a result, a single beam of internally coupled light may be "replicated" each time a portion of that light is redirected by an OPE or EPE, thereby forming a cloned beam field of light, as shown in Figure 6. In some embodiments, the OPE and / or EPE may be configured to modify the size of the beam of light.

[0127] Thus, referring to Figures 9A and 9B, in some embodiments, a set of waveguides 660 includes, for each primary color, a waveguide 670, 680, 690, an in-coupling optical element 700, 710, 720, an optical dispersion element (e.g., OPE) 730, 740, 750, and an out-coupling optical element (e.g., EP) 800, 810, 820. The waveguides 670, 680, 690 may be stacked with an air gap / cladding layer between each one. The in-coupling optical element 700, 710, 720 redirects or deflects the incoming light into its waveguide (with different in-coupling optical elements receiving different wavelengths of light). The light then propagates at an angle that will result in TIR within the individual waveguides 670, 680, 690. In the illustrated embodiment, light ray 770 (e.g., blue light) is deflected by the first in-coupling optical element 700 in the manner described above, then continues to bounce back down the waveguide, interacting with the optically dispersive element (e.g., OPE) 730 and then the out-coupling optical element (e.g., EP) 800. Light rays 780 and 790 (e.g., green and red light, respectively) pass through the waveguide 670, with light ray 780 incident on the in-coupling optical element 710 and being deflected thereby. Light ray 780 will then proceed via TIR back down the waveguide 680, to its optically dispersive element (e.g., OPE) 740 and then the out-coupling optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) passes through the waveguide 690 and impinges on the optically in-coupling optical element 720 of the waveguide 690. The light in-coupling optical element 720 deflects the light beam 790 such that it propagates by TIR to a light dispersive element (e.g., OPE) 750 and then by TIR to an out-coupling optical element (e.g., EP) 820. The out-coupling optical element 820 then finally out-couples the light beam 790 to a viewer, who also receives the out-coupled light from the other waveguides 670, 680.

[0128] FIG. 9C illustrates a top-down plan view of an example of the multiple stacked waveguides of FIGS. 9A and 9B. As shown, the waveguides 670, 680, 690 may be vertically aligned with each waveguide's associated light dispersive element 730, 740, 750 and associated out-coupling optical elements 800, 810, 820. However, as discussed herein, the in-coupling optical elements 700, 710, 720 are not vertically aligned. Rather, the in-coupling optical elements are preferably non-overlapping (e.g., laterally spaced apart, as seen in the top-down view). As discussed further herein, this non-overlapping spatial arrangement facilitates the injection of light from different sources 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, an arrangement including non-overlapping spatially separated in-coupling optical elements may be referred to as a shifted pupil system, and the in-coupling optical elements in these arrangements may correspond to sub-pupils.

[0129] 9D illustrates an example of a wearable display system 60 into which the various waveguide and associated systems disclosed herein may be integrated. In some embodiments, the display system 60 is the system 250 of FIG. 6, which diagrammatically illustrates some portions of the system 60 in greater detail. For example, the waveguide assembly 260 of FIG. 6 may be part of the display 70.

[0130] 9D , the display system 60 includes a display 70 and various mechanical and electronic modules and systems to support the functionality of the display 70. The display 70 may be coupled to a frame 80, which is wearable by a display system user or viewer 90 and configured to position the display 70 in front of the user's 90 eye. The display 70 may be considered eyewear in some embodiments. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned adjacent to the ear canal of the user 90 (in some embodiments, another speaker, not shown, may also be optionally positioned adjacent the user's other ear canal to provide stereo / shapeable sound control). The display system 60 may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphones may be configured to allow the user to provide input or commands to the system 60 (e.g., voice menu command selection, natural language queries, etc.) and / or enable audio communication with other persons (e.g., other users of similar display systems). The microphone may further be configured as an ambient sensor and collect audio data (e.g., sounds from the user and / or the environment). In some embodiments, the display system 60 may further include one or more outwardly directed environmental sensors 112 configured to detect objects, stimuli, people, animals, places, or other aspects of the world around the user. For example, the environmental sensors 112 may include, for example, one or more cameras that may be oriented outwardly and positioned to capture images similar to at least a portion of the user 90's normal field of view. In some embodiments, the display system may also include an ambient sensor 120a, which may be separate from the frame 80 and mounted on the body of the user 90 (e.g., the head, torso, limbs, etc. of the user 90). The ambient sensor 120a may, in some embodiments, be configured to obtain data characterizing a physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0131] 9D, the display 70 is operably coupled to the local data processing module 140 by a communication link 130, such as wired or wireless connectivity, which may be mounted in a variety of configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded within headphones, or otherwise removably attached to the user 90 (e.g., in a backpack configuration, in a belt-connected configuration). Similarly, the sensor 120a may be operably coupled to the local processor and data module 140 by a communication link 120b, such as wired or wireless connectivity. The local processing and data module 140 may comprise a hardware processor and digital memory, such as non-volatile memory (e.g., flash memory or hard disk drive), both of which may be utilized to aid in processing, caching, and storing data. Optionally, the local processing and data module 140 may include one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, and the like. The data may include a) data captured from sensors (such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, gyroscopes, and / or other sensors disclosed herein (e.g., which may be operatively coupled to the frame 80 or otherwise attached to the user 90)) and / or b) data acquired and / or processed using the remote processing module 150 and / or remote data repository 160 (including data related to virtual content), possibly for passing to the display 70 after processing or retrieval. The local processing and data module 140 may be operatively coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180, such as via wired or wireless communication links, such that these remote modules 150, 160 are operatively coupled to each other and available as resources to the local processing and data module 140.In some embodiments, local processing and data module 140 may include one or more of an image capture device, a microphone, an inertial measurement unit, an accelerometer, a compass, a GPS unit, a wireless device, and / or a gyroscope. In some other embodiments, one or more of these sensors may be mounted on frame 80 or may be a stand-alone structure that communicates with local processing and data module 140 by a wired or wireless communication path.

[0132] 9D , in some embodiments, remote processing module 150 may comprise one or more processors configured to analyze and process data and / or image information, and may include, for example, one or more central processing units (CPUs), graphics processing units (GPUs), special purpose processing hardware, etc. In some embodiments, remote data repository 160 may comprise digital data storage facilities that may be available through the Internet or other networking configurations in a "cloud" resource configuration. In some embodiments, remote data repository 160 may include one or more remote servers, which provide information, for example, information for generating augmented reality content to local processing and data module 140 and / or remote processing module 150. In some embodiments, all data is stored and all computations are performed within the local processing and data module, allowing for fully autonomous use from the remote modules. Optionally, an external system (e.g., one or more processors, one or more computer systems), including a CPU, GPU, etc., may perform at least a portion of the processing (e.g., generating image information, processing data) and provide information to and receive information from modules 140, 150, 160, e.g., via a wireless or wired connection. Compatible Lens Assembly

[0133] 9A , some display systems include a waveguide assembly 660 configured to form an image at multiple virtual depth planes. In the illustrated embodiment, the image may be formed, for example, using multiple waveguides 670, 680, 690 configured to form an image at one of the different depth planes. The waveguide assembly 660 may also include additional waveguides having different optical powers and forming images at different virtual depth planes. However, because each of the waveguides 670, 680, 690 increases the overall thickness, weight, and cost of the waveguide assembly 660, it would be desirable to form images at multiple virtual depth planes using fewer waveguides.

[0134] In various embodiments described herein, the display device is configured to form images at different virtual depth planes using a waveguide assembly and one or more adaptive lens assemblies. In some embodiments, the adaptive lens assemblies comprise liquid crystals, which can form a lens assembly that is lighter and thinner (a few microns) than conventional lenses, and which can advantageously be configured to be switchable (e.g., electrically switchable). Advantageously, such adaptive lens assemblies can reduce the number, thickness, and weight of waveguide assemblies such as assembly 660.

[0135] As used herein, optical power (also referred to as refractive power, focusing power, or converging power) is the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the inverse of the focal length of the device: P=1 / f. That is, high optical power corresponds to a short focal length. The SI unit for optical power is per meter (m -1), which is commonly referred to as a diopter. As described herein, a converging lens is described as having a positive refractive power, while a diverging lens is described as having a negative refractive power. Without being bound by theory, when light passes through two or more thin lenses that are relatively close to each other, the refractive power of the combined lenses can be approximated as the sum of the refractive powers of the individual lenses. Thus, when light passes through a first lens having a first refractive power P1 and further passes through a second lens having a second refractive power P2, the light can be understood to converge or diverge according to the sum of the refractive powers P=P1+P2.

[0136] FIG. 10 illustrates an example of a display device 1000, e.g., a wearable display device, comprising one or more adaptive lens assemblies, e.g., a pair of adaptive lens assemblies 1004, 1008, in an optical path 1016, interposed by a waveguide assembly 1012. In some embodiments, the waveguide assembly 1012 may correspond to a waveguide stack 260 or 660. As described herein, the waveguide assembly includes a waveguide configured to propagate light (e.g., visible light) under total internal reflection and to outcouple the light in an optical axis extending from (e.g., normal to) a light output surface of the waveguide. Preferably, the light output surface is a major surface of the waveguide (e.g., a major surface of a waveguide may be understood to be a broad surface of the waveguide between which the thickness, e.g., smallest dimension, of the waveguide extends). The light may be outcoupled by a diffraction grating in some embodiments. Each of the adaptive lens assemblies 1004, 1008 may be configured to at least partially transmit the outcoupled light therethrough. As shown, each of the adaptive lens assemblies 1004, 1008 may be configured to receive the outcoupled light from the waveguide assembly 1012 and converge or diverge the outcoupled light along an optical axis. Each of the adaptive lens assemblies 1004, 1008 may comprise a waveplate lens and a switchable waveplate assembly, which itself comprises first and second waveplate lenses interposed by a switchable waveplate. Each of the waveplates may be configured to alter the polarization state of the outcoupled light passing therethrough. The switchable waveplates may be configured to alter the polarization state of the outcoupled light passing therethrough when activated (e.g., electrically activated).

[0137] As used herein, an adaptive lens assembly refers to a lens assembly having at least one optical property that can be adjusted, e.g., reversibly activated and deactivated using an external stimulus. Exemplary optical properties that can be reversibly activated and deactivated include, among other properties, refractive power (focal length), phase, polarization, polarization selectivity, transmittance, reflectance, birefringence, and diffractive properties. In various embodiments, an adaptive lens assembly is capable of varying the refractive power and polarization state of light passing therethrough by this selective application of an electric field.

[0138] In the illustrated embodiment, the pair of adaptive lens assemblies 1004, 1008 are each configured to be electrically activated and deactivated, such that in a deactivated state, the adaptive lens assemblies 1004, 1008 each provide a first refractive power, while in an activated state, the adaptive lens assemblies 1004, 1008 each provide a second refractive power that is different from the first refractive power. Additionally, in some embodiments, in one state, the adaptive lens assemblies 1004, 1008 each modify the polarization state of light (e.g., visible light) passing therethrough, while in another state, the adaptive lens assemblies 1004, 1008 each preserve the polarization state of light passing therethrough.

[0139] Still referring to FIG. 10, the display device 1000 further comprises a waveguide assembly 1012 interposed between the pair of adaptive lens assemblies 1004, 1008. The waveguide assembly 1012 may be similar to the waveguide assemblies 260 or 660 described above with respect to FIGS. 6 and 9A-9C, respectively. The waveguide assembly 1012 may comprise a waveguide similar to the waveguides 270, 280, 290, 300, 310 of FIG. 6 or the waveguides 670, 680, 690 of FIGS. 9A-9C. As described herein, the waveguide may be configured to propagate light in a lateral direction parallel to the major surface of the waveguide under total internal reflection. The waveguide may further be configured to outcouple the light and output the light through the adaptive lens assembly 1008 to the user's eye 210.

[0140] Still referring to FIG. 10 , a first adaptive lens assembly 1004 of the pair of adaptive lens assemblies is disposed on a first side of the waveguide assembly 1012, e.g., the side of the world 510 observed by the user, and a second adaptive lens assembly 1008 of the pair of lens assemblies is disposed on a second side of the waveguide assembly 1012, e.g., the side closest to the user's eye 210. As described below, the pair of adaptive lens assemblies as configured provide the user with virtual content from the waveguide assembly 1012 in multiple virtual depth planes along with a view of the real world. In some embodiments, there is little or no distortion due to the presence of the adaptive lens assemblies. The virtual content and views of the real world are provided to the user in response to activation of the first and second adaptive lens assemblies 1004, 1008, as described below with respect to FIGS. 11A and 11B.

[0141] 11A and 11B illustrate examples of display devices 1100A / 1100B, each with an adaptive lens assembly, that, in operation, output image information to a user. The display devices 1100A and 1100B may be structurally identical in an unpowered state. The display device 1100A is used herein to illustrate outputting a virtual image to a user, while the display device 1100B is used herein to illustrate transmitting a real-world image to a user through the display device 1100B. The display devices 1100A / 1100B include a pair of adaptive lens assemblies 1004, 1008 that are configured to be electrically activated, for example, by application of a voltage or current. In some embodiments, in a deactivated state, for example, where no voltage or current is applied, the first and second switchable lens assemblies 1004, 1008 each have a low, e.g., about zero, optical power. In some embodiments, in an activated state, e.g., when a voltage or current is applied, the first world side adaptive lens assembly 1004 on the world side may provide a first net refractive power (Pnet1) having a first sign, e.g., positive refractive power, and the second user side adaptive lens assembly 1008 on the user side may provide a second net refractive power (Pnet2) having a second sign, e.g., negative refractive power, when in the activated state.

[0142] FIG. 11A illustrates an example of the display system of FIG. 10 that displays virtual content to a user in a virtual depth plane, according to some embodiments. As described herein, the waveguide assembly 1012, interposed between a pair of adaptive lens assemblies 1004, 1008, comprises a waveguide configured to receive light containing virtual image information and propagate the light under total internal reflection. The waveguide assembly 1012 is further configured to outcouple the light toward the eye 210, for example, through a diffraction grating. The outcoupled light passes through the second adaptive lens assembly 1008 prior to entering the eye 210. When activated, the second adaptive lens assembly 1008 has a second net refractive power Pnet2, which may have a negative value, such that the user sees a virtual image in the virtual depth plane 1104.

[0143] In some embodiments, the second net refractive power Pnet2 may be electronically adjusted to adjust the second net refractive power (Pnet2) of the second adaptive lens assembly 1008, thereby adjusting the distance to the virtual depth plane 1104. For example, as a virtual object "moves" closer and farther in the virtual three-dimensional space relative to the eye 210, the second net refractive power Pnet2 of the second adaptive lens assembly 1008 may be correspondingly adjusted such that the virtual depth plane 1104 is adjusted to track the virtual object. Thus, the user may experience relatively little or no accommodation / vergence-divergence mismatch beyond an acceptable threshold. In some embodiments, the magnitude of the distance to the virtual depth plane 1104 may be adjusted in discrete steps, while in some other embodiments, the magnitude of the distance to the virtual depth plane 1104 may be adjusted continuously.

[0144] 11B illustrates an example of the display system of FIG. 10 providing a user with a view of real-world content, according to some embodiments. When the second adaptive lens assembly 1008 is activated to have a second net refractive power (Pnet2) for displaying virtual content in the virtual depth plane 1104, light from the real world passing through the second adaptive lens assembly 1008 may also converge or diverge according to the Pnet2 of the activated second adaptive lens assembly 1008. Thus, objects in the real world may appear out of focus. To mitigate such distortion, according to some embodiments, when activated, the first and second adaptive lens assemblies 1004, 1008 may be configured to have refractive powers with opposite signs. In some embodiments, light passing through the first and second adaptive lens assemblies 1004, 1008 converges or diverges according to a combined refractive power having a magnitude approximately equal to the difference between the magnitudes of the first and second net refractive powers Pnet1, Pnet2 of the first and second adaptive lens assemblies 1004, 1008, respectively. In some embodiments, the waveguide assembly 1012 may also have a refractive power, and the adaptive lens assembly 1008 may be configured to account for distortions caused by both the lens assembly 1004 and the waveguide assembly 1012. For example, the refractive power of the adaptive lens assembly 1008 may be the opposite sign of the sum of the refractive powers of the lens assembly 1004 and the waveguide assembly 1012.

[0145] In some embodiments, the first adaptive lens assembly 1004 is configured to have a first net refractive power Pnet1 having a magnitude that is close to or identical to the magnitude of the second net refractive power Pnet2 of the second adaptive lens assembly 1008. As a result, when both the first and second adaptive lens assemblies 1004, 1008 are activated simultaneously, objects in the real world appear relatively unaffected by the refractive power of the second adaptive lens assembly 1008 that is provided to display virtual content.

[0146] In some embodiments, the first adaptive lens assembly 1004 may be configured such that, when activated, the first net refractive power Pnet1 dynamically matches the second net refractive power Pnet2 of the second adaptive lens assembly 1008. For example, as the second net refractive power Pnet1 of the second switchable assembly 1008 is adjusted to track a moving virtual object in the virtual three-dimensional space, the first net refractive power Pnet1 of the first adaptive lens assembly 1004 may be dynamically adjusted such that the magnitude of the combined refractive power P=Pnet1+Pnet2 may be kept below a predetermined value. Thus, according to an embodiment, an object in the real world may be adjusted such that the magnitude of the combined refractive power P=Pnet1+Pnet2 is small, e.g., approximately 0 m. -1 By compensating the second net refractive power (Pnet2) of the second adaptive lens assembly 1008, which may have a negative value, with the first net refractive power (Pnet1) of the first adaptive lens assembly 1004 so that the second net refractive power (Pnet2) of the second adaptive lens assembly 1008 remains negative, unacceptable focus can be prevented.

[0147] 12 illustrates an example of a display device 1500 including a pair of adaptive lens assemblies, each including an adaptive lens subassembly including a waveplate lens and a switchable waveplate. The first and second adaptive lens assemblies 1504, 1508 each include a plurality of waveplate lenses, e.g., first to third waveplate lenses 1308-1, 1308-2, 1308-3, stacked alternately with a plurality of switchable waveplate assemblies, e.g., first to third switchable waveplate assemblies 1312-1, 1312-2, 1312-3. The waveplate lenses 1308-1, 1308-2, 1308-3 and adjacent switchable waveplate assemblies 1312-1, 1312-2, 1312-3 form subassemblies 1504-1, 1504-2, 1504-3, respectively. Each of the multiple switchable waveplate assemblies 1312 may be independently activated using switching circuitry. In some embodiments, electrically activating different ones of the switchable waveplates causes light passing through the adaptive lens assembly to diverge or converge according to different net refractive powers having magnitudes that are approximately the sum of the magnitudes of the refractive powers of immediately adjacent waveplate lenses interposed by the different ones of the switchable waveplate assemblies.

[0148] Advantageously, by selecting different ones of one or more of the subassemblies 1508-1, 1508-2, 1508-3 in the second adaptive lens assembly 1508, virtual images at different depth planes may be displayed to the user, and in addition, by selecting different corresponding ones of the subassemblies 1504-1, 1504-2, 1504-3 in the first adaptive lens assembly 1504, defocus or distortion of the real world image that may result from the refractive powers of the subassemblies 1508-1, 1508-2, 1508-3 may be compensated for or reduced. Adaptive lens assembly with fixed lens

[0149] In the exemplary display devices described above that include an adaptive lens assembly, the adaptive lens assembly included a waveplate lens and a switchable waveplate, which has the advantage of, among other things, reducing the number of waveguides and thus reducing the overall device weight and thickness. In some embodiments, additional fixed lenses may be stacked on one or more adaptive lens assemblies. Advantageously, the additional lenses provide various possible advantages. For example, under some circumstances, such lenses may be provided to add additional refractive power. In addition, some users who use a wearable display device according to some embodiments, such as the wearable device 1000 described with respect to FIG. 10, have eyes with refractive errors that prevent light from being correctly focused on the retina of that eye. In some embodiments, the additional lens elements may be configured to provide a specific prescription refractive power and allow the user to clearly view image information projected by the display and / or transmitted from the real world through the display. Additionally, the additional lens may have a surface with a curvature to allow the device to better conform to the contours of the user's face, to better integrate with normal frames for eyewear, and / or to provide a more aesthetically pleasing appearance to the display device.

[0150] 13A and 13B illustrate a display device comprising a pair of adaptive lens assemblies and a pair of fixed lenses, according to some embodiments. As discussed above, display device 1800A / 1800B comprises a pair of adaptive lens assemblies (e.g., 1504, 1508 in FIG. 12) and a waveguide assembly 1012 interposed between the pair of adaptive lens assemblies, the waveguide assembly comprising a waveguide configured to propagate light under total internal reflection, out-couple the light into one of the pair of adaptive lens assemblies (including 1005, 1504 on one side and 1508, 1008 on the other side), and display virtual content in multiple virtual depth planes.

[0151] As discussed above, in some circumstances, it may be desirable to add an additional fixed lens, e.g., a corrective lens, to allow the user to see more clearly. In some embodiments, a first fixed focus lens element 1808 may be provided between the waveguide assembly 1012 and the viewer's eye 210. The addition of the first fixed focus lens element may provide proper accommodation and adjust the light coupled out of the waveguide assembly 1012, which may include virtual content, to be properly focused for the viewer's eye 210. However, the first fixed focus lens element 1808 is also in the path of light propagating from the world 510 to the viewer's eye 210. As a result, the first lens element may modify light from the surrounding environment, thereby causing aberrations in the viewer's view of the world. To correct such aberrations, a second fixed focus lens element 1804 may be disposed on the opposite side of the waveguide assembly 1012 from the first variable focus lens element 1808. The second fixed focus lens element 1804 may be configured to compensate for aberrations caused by the first fixed focus lens element 1808.

[0152] In some embodiments, the focus of the second fixed focus lens element 1804 may be the inverse or opposite of the focus of the first fixed focus lens element 1808. For example, if the first fixed focus lens element 1808 has a positive refractive power, the second fixed focus lens element 1804 may have a negative refractive power, and vice versa, which may be of similar magnitude in some embodiments.

[0153] In some embodiments, the display device 1800A / 1800B without the fixed focus lens elements 1804, 1808 may not have sufficient refractive power, and the first variable focus lens element may be configured to provide an appropriate amount of additional divergence to the light for the image information to be interpreted by a viewer as being at a particular depth plane.

[0154] It should be understood that first and second fixed focus lens elements 1804, 1808, respectively, may be provided for one of the viewer's eyes, and third and fourth fixed focus lens elements (not shown) similar to the first and second fixed focus lens elements (but possibly with different refractive powers) may be provided for the other of the viewer's eyes.

[0155] In various embodiments, the first and second fixed focus lens elements may each provide a net optical power (positive or negative) within the range of approximately ±5.0 diopters to 0 diopters, ±4.0 diopters to 0 diopters, ±3.0 diopters to 0 diopters, ±2.0 diopters to 0 diopters, ±1.0 diopters to 0 diopters (including any range defined by these values, e.g., ±1.5 diopters).

[0156] 13A and 13B, the refractive power of the first fixed focus lens element 1804, which may be, for example, a concave or plano-concave lens, has a positive value and the refractive power of the second fixed focus lens element 1808, which may be, for example, a convex or plano-convex lens, has a negative value, such that the refractive powers of the first and second fixed focus lens elements 1804, 1808 compensate each other. However, in some other embodiments, the refractive power of the second fixed focus lens element 1808 may have a positive value and the refractive power of the first fixed focus lens element 1804 may have a negative value, such that the refractive powers of the first and second fixed focus lens elements 1804, 1808 compensate each other.

[0157] FIG. 14 illustrates a display device 1900 according to some other embodiments. Similar to the display devices 1800A / 1800B described above with respect to FIGS. 13A, 13B, the display device 1900 includes a pair of adaptive lens assemblies (e.g., 1504, 1508 in FIG. 12) and a waveguide assembly 1012 interposed between the pair of adaptive lens assemblies. However, unlike the display devices 1800A / 1800B of FIGS. 13A, 13B, the waveguide assembly 1012 may be configured to have built-in refractive power instead of having a first fixed focus lens element 1808 between the waveguide assembly 1012 and the viewer's eye 210 to adjust the light coupled out from the waveguide assembly 1012, which may include virtual content, so that it is properly focused for the viewer's eye 210. Similar to the display devices 1800A / 1800B described above, the built-in refractive power in the waveguide assembly 1012 may modify the wavefront of light from the surrounding environment, thereby causing aberrations in the viewer's view of the world. To correct such aberrations, a fixed focus lens element 1804, similar to the second fixed focus lens element 1804 described above with respect to FIGS. 13A, 13B, may be disposed between the world and the waveguide assembly 1012. The fixed focus lens element 1804 may be configured to compensate for the aberrations caused by the built-in refractive power in the waveguide assembly 1012, similar to the compensation mechanism described above with respect to FIGS. 13A, 13B. In some embodiments, the built-in refractive power in the waveguide assembly 1012 may have a negative value and the refractive power of the fixed focus lens element 1804 may have a positive value, such that the refractive powers of the waveguide assembly and the fixed focus lens element compensate each other. Various characteristics of the fixed focus lens element 1804 are similar to those described above with respect to Figures 13A and 13B.

[0158] 14, the fixed focus lens element 1804 is disposed between the world 510 and the waveguide assembly 1012, although it should be understood that other embodiments are possible. For example, a fixed focus lens element 1808 may be disposed between the eye 210 and the waveguide assembly 1012, similar to the first fixed focus lens element 1808 described above with respect to FIGS. 13A, 13B. In these embodiments, the built-in refractive power within the waveguide assembly 1012 may have a positive value and the refractive power of the fixed focus lens element 1808 may have a negative value, such that the refractive powers of the waveguide assembly and the fixed focus lens element compensate each other (e.g., sum to substantially zero). Switchable variable focus element component

[0159] FIG. 15 illustrates an exemplary adaptive lens assembly 1200 comprising three adaptive lens subassemblies 1210. The adaptive lens assembly 1200 may be, for example, a front lens assembly 1004, 1504 or a rear lens assembly 1008, 1508 as shown in FIGS. 10-12. Each layer 1210 includes a waveplate lens 1212 and a switchable liquid crystal layer 1214. A conductive layer 1216, such as one or more conductive wire or mesh layers, is included within each of the several assemblies 1210 for selective switching of the switchable liquid crystal layer 1214. In some proposed configurations, the subassemblies 1210 may require an additional support substrate 1218 and a matching layer 1222. An adhesive 1220 and further coating layers 1224 (e.g., anti-reflective layers) are provided between the various layers and between the lens layers 1210. It should be appreciated that the presence of multiple support substrates 1218 and matching layers 1222 can significantly increase the weight and thickness of the adaptive lens assembly 1200. Therefore, a thinner and lighter adaptive lens assembly structure may be desirable.

[0160] 16A and 16B illustrate an exemplary adaptive lens assembly 1400, each comprising three adaptive lens subassemblies, according to various embodiments. Advantageously, the adaptive lens assembly 1400 has a simplified structure relative to the adaptive lens assembly 1200 of FIG. 15. In some embodiments, the structure shown in FIGS. 16A and 16B may advantageously provide an adaptive lens assembly that is thinner and lighter than existing adaptive lens assemblies and may be manufactured more efficiently. The illustrated adaptive lens assemblies 1400 depicted in FIGS. 16A and 16B each include three adaptive lens subassemblies 1410. However, it should be understood that the adaptive lens assembly 1400 may be implemented with fewer than three adaptive lens subassemblies (e.g., one or two subassemblies) or more than three adaptive lens subassemblies (e.g., four, five, six, or more subassemblies). It should be understood that the adaptive lens assembly 1400 may correspond to the lens assemblies 1004, 1504, 1008, 1508 of FIGS. 10-14, such that the adaptive lens assembly 1400 may be utilized in place of the lens assemblies 1004, 1504, 1008, 1508.

[0161] 16A and 16B, the adaptive lens assembly 1400 includes three adaptive lens subassemblies 1410 bonded by an adhesive layer 1424 (e.g., comprising an index-matching adhesive). Each adaptive lens subassembly 1410 includes at least one waveplate lens 1412, 1412a, 1412b. For example, FIG. 16A depicts an adaptive lens subassembly 1410 including a single waveplate lens 1412, while FIG. 16B depicts an adaptive lens subassembly 1410 including a first waveplate lens 1412a and a second waveplate lens 1412b. The multiple lens configuration shown in FIG. 16B may be desirable if the lenses 1412a, 1412b are of a type that affect only a subset of wavelengths. Thus, multiple adjacent lenses 1412a, 1412b can be combined to form a system that would provide the desired optical power over a larger wavelength range.

[0162] Each adaptive lens subassembly 1410 further includes a switchable waveplate assembly comprising two quarter waveplates 1416 and a switching cell wall 1418 that defines an enclosed volume between the quarter waveplates 1416. Preferably, the quarter waveplates 1416 are formed from an optically transmissive material that is flexible (allowing the quarter waveplates 1416 to be rolled up and unrolled), mechanically stable, and sufficiently inelastic for use in roll-to-roll processing as disclosed herein. Preferably, the material does not comprise liquid crystals. Examples of suitable materials for the quarter waveplates 1416 include plastic (polymer) sheets such as polycarbonate or equivalent.

[0163] The quarter wave plate 1416 and the switching cell walls 1418 encapsulate the switching medium 1414 (e.g., liquid crystal material) and the conductive material 1420 (e.g., wires, conductive mesh, etc.). In some embodiments, the conductive material 1420 is an indium tin oxide (ITO) layer, which may be patterned into a pattern of electrodes. A matching layer may be provided between the switchable wave plate assembly and the wave plate lenses 1412, 1412a, 1412b. The matching layer may include one or more matching structures for proper vertical, horizontal, and / or rotational alignment of the adaptive lens subassembly 1410. Alternatively, in some embodiments, the matching layer 1422 may be omitted and one or more matching structures may be added to and / or imprinted into the surfaces of adjacent quarter wave plates 1416 and / or lenses 1412, 1412a.

[0164] With respect to the adaptive lens subassembly 1210 depicted in FIG. 15, the adaptive lens subassembly 1410 depicted in FIGS. 16A and 16B may advantageously have fewer component layers. The quarter wave plate 1416 may provide sufficient structural support to each lens subassembly 1410 such that an additional support substrate 1218 (FIG. 15) is not required. In addition, the switchable wave plate of the adaptive lens subassembly 1410 includes a conductive material 1420 in the space occupied by the switchable wave plate layer 1414 (e.g., a liquid crystal layer) in the form of a mesh or wire integrated with the quarter wave plate 1416 such that an additional conductive layer 1216 (FIG. 15) is not required. As a non-limiting example of an advantageously thin adaptive lens assembly described herein, the adaptive lens assembly 1400 depicted in FIG. 16B may have an overall thickness of 1 mm to 3 mm, such as about 1.3 mm. For example, each quarter wave plate may have a thickness of 100 microns to 300 microns (e.g., 200 microns), each switching cell wall 1418 may have a thickness of 5 to 20 microns (e.g., 10 microns), each wave plate lens 1412a, 1412b may have a thickness of 1 to 5 microns (e.g., 2 microns), and each matching layer, if present, may have a thickness of less than 100 nm (e.g., 20 nm to 30 nm). Thus, each adaptive lens subassembly 1410 may have a thickness of approximately 414 microns. The adhesive layers 1424 may each have a thickness of 10 to 50 microns (e.g., 20 microns) such that the adaptive lens assembly 1400 has a total thickness of approximately 1.3 mm. Method and apparatus for manufacturing variable focus elements

[0165] 17A-17E illustrate an example process for manufacturing an adaptive lens assembly, such as the adaptive lens assembly 1400 described with reference to FIGS. 16A and 16B. It should be understood that individual parts of the process may be added or omitted without departing from the scope of the present disclosure. As will be described in more detail, the process may generally include forming a quarter wave plate substrate 1430 and a lens substrate 1440 (which may be formed by adding a lens layer to an existing quarter wave plate substrate 1430), combining the quarter wave plate substrate 1430 and the lens substrate 1440 to form an adaptive lens subassembly 1410 and a gap, i.e., a volume that encloses the switchable liquid crystal layer 1414 of FIGS. 16A and 16B. A plurality of adaptive lens subassemblies 1410 may then be combined in a stack (e.g., glued together using an index-matched adhesive layer) to form the adaptive lens assembly 1400.

[0166] As shown in FIG. 17A, a conductive material 1420 can be formed as a mesh and / or an array of wires (e.g., parallel wires) on each quarter-wave plate 1416 to form a quarter-wave plate substrate 1430. For example, the conductive material 1420 can be formed directly on each quarter-wave plate 1416 by a process including one or more of imprinting, deposition, etching, sputtering, and / or washing. Various methods for forming a pattern of conductive material 1420 are further discussed herein, for example, with respect to FIGS. 21A-27D. In addition, methods for forming a pattern of conductive material 1420 are also disclosed in U.S. Patent Application No. 15 / 683,706, filed August 22, 2017, the entire disclosure of which is incorporated herein by reference. In some embodiments, a metal layer can be deposited on the quarter-wave plate substrate 1430 and then patterned to define electrodes and form an electrode pattern on the surface of the substrate 1430. In various embodiments, the conductive material 1420 may be formed on a sheet of quarter wave plate substrate, a singulated quarter wave plate layer, and / or a larger roll of quarter wave plate substrate (e.g., in a roll-to-roll manufacturing process). In some embodiments, the orientation, size, spacing, or other aspects of the conductive layer can be selected such that the wires form alignment guides for the liquid crystal layer 1414 (FIGS. 16A, 16B). Additional surface features may also be imprinted into the quarter wave plate substrate in some embodiments to further guide alignment of the liquid crystal molecules in the liquid crystal layer 1414. In some embodiments, the substrate fed onto the first roller may include a preformed pattern of electrodes on the back surface of the substrate. Additional methods of forming features on a substrate are also disclosed in U.S. Patent Application Serial No. 15 / 990,155, filed May 25, 2018, the entire disclosure of which is incorporated herein by reference.

[0167] FIG. 17B depicts further steps in an exemplary manufacturing process. As shown in FIG. 17B, the quarter wave plate 1416 includes a matching layer 1422, a first wave plate lens 1412a, and a second wave plate lens 1412b forming a lens substrate 1440. In some embodiments, the matching layer 1422 may include one or more matching features printed on the side of the quarter wave plate 1416 opposite the electrodes or conductive material 1420. After the matching layer 1422 and / or other matching structures are created on the surface of the quarter wave plate 1416, the first wave plate lens 1412a and the second wave plate lens 1412b are formed. For example, each lens 1412a, 1412b may be formed by depositing a layer of liquid crystal (e.g., by a slot die or other deposition device) and curing each layer to polymerize the liquid crystal and form the wave plate lens 1412a, 1412b. It should be appreciated that the alignment structures of the alignment layer 1422 and / or the alignment structures on the surface of the quarter wave plate 1416 aid in the alignment of the liquid crystal molecules in the first wave plate lens 1412a. The alignment of the crystals may then be retained (e.g., via polymerization of the liquid crystal molecules) when the first lens 1412a is cured, such as by ultraviolet (UV) radiation and / or heat. The second lens 1412b may similarly be applied in a flowable form and cured using UV radiation and / or heat.

[0168] As shown in FIG. 17C, switching cell walls 1418 may further be added on the lens substrate 1440 on the side including the conductive material 1420. For example, the cell walls 1418 may comprise an inkjet printable material such that the cell walls 1418 may be printed on the quarter wave plate 1416 by inkjet printing. In some embodiments, additional spacing structures may be added at locations between the cell walls 1418 to maintain substrate spacing along all locations between the cell walls 1418. For example, the spacing structures may be inkjet printed with the same or different material used to print the cell walls 1418. Additionally, during the inkjet printing phase, a conductive material may be printed to interconnect the conductive materials 1420. For example, if the conductive material 1420 comprises an array of parallel wires, one or more lines of conductive inkjet printable material may be printed perpendicular or at an angle to the parallel wires such that the conductive material 1420 are interconnected and may effectively apply a voltage difference across the liquid crystal layer 1414 depicted in Figures 16A and 16B. In one exemplary manufacturing process, the component shown in Figure 17B may be formed in a roll-to-roll process and cut into sheets, as shown in Figure 17C, prior to printing the cell walls 1418.

[0169] As shown in FIG. 17D, the quarter wave plate substrate 1430 is bonded to the lens substrate 1440 to complete the adaptive lens subassembly 1410. The gap created between the quarter wave plate substrate 1430 and the lens substrate 1440 is filled with liquid crystal material. For example, the lens substrate 1440 may be placed in a horizontal orientation. The liquid crystal material may be dispensed onto the lens substrate 1440 such that the spaces between the cell walls 1418 are filled with the liquid crystal material. The quarter wave plate substrate 1430 may then be glued or otherwise affixed in place relative to the lens substrate 1440 to retain the liquid crystal material. Preferably, the adaptive lens subassembly 1410 is formed such that no air is retained within the liquid crystal material. For example, the filling and assembly may be performed in a vacuum and / or the space for the liquid crystal may be overfilled such that the space between the quarter wave plates 1416 is substantially filled with the switching medium and substantially free of air, and an air vent may be provided in at least one cell wall 1418. In some other embodiments, the lens substrate 1440 and the quarter wave plate substrate 1430 may be bonded together to form an open volume, and then liquid crystal is introduced to fill the volume. Although the cell walls 1418 are shown printed on the lens substrate 1440, in some embodiments the cell walls 1418 may be printed on the quarter wave plate substrate 1430 rather than the lens substrate 1440, and the filling and assembly steps may be performed with the lens substrate 1440 placed on top of the quarter wave plate substrate. In some embodiments, portions of the cell walls 1418 may be printed on both the quarter wave plate substrate 1430 and the lens substrate 1440.

[0170] After the adaptive lens subassemblies 1410 are formed, they may be stacked with one or more additional adaptive lens subassemblies 1410 to form the adaptive lens assembly 1400 comprising a stack of adaptive lens subassemblies 1410, as shown in FIG. 17E. Each pair of adaptive lens subassemblies 1410 may be bonded together by an adhesive layer 1424. It should be understood that the relative orientation of the wave plates with respect to one another affects the optical properties of the subassembly 1410 and the larger adaptive lens assembly 1400. Preferably, when bonding the adaptive lens subassemblies 1410 together, it may be desirable to align each lens subassembly 1410 with each adjacent lens subassembly 1410, for example, with an accuracy of within about 100 microns laterally in the x and y dimensions, and with a rotation of about 0.1 mrad.

[0171] 18A illustrates an exemplary apparatus for roll-to-roll manufacturing of lens substrates using an optical alignment process for adaptive lens assemblies. The lens substrate 1650 formed by the apparatus 1600A may be, for example, the lens substrate 1440 depicted in FIG. 17B. The apparatus 1400A is configured to receive a supply substrate 1605 in the form of a supply substrate roll, which may be disposed about a roller 1602, and produce the lens substrate 1650, which may also be in the form of a lens substrate roll 1655, for further processing. In some embodiments, the supply substrate may have a composition and / or cross-sectional profile that matches the quarter wave plate substrate 1430 depicted in FIG. 17A.

[0172] The feed substrate roll 1602 may include a feed substrate 1605 with a protective film 1610. The protective film 1610 may be removed before further layers are applied. A matching slot die 1615 applies a matching layer 1617, which may include a photosensitive material such as a resist material (e.g., a photoresist, such as a positive photoresist or a negative photoresist), or a holographic medium on which holographic recording may occur. The feed substrate 1605 may advance over a matching application roller 1619 adjacent the matching slot die 1615 (e.g., the matching application roller 1619 may be located directly or approximately below the matching slot die 1615). The matching application roller 1619 may stabilize the feed substrate 1605 as it advances under the matching slot die 1615, ensuring uniform coating of the matching layer 1617 onto the feed substrate 1605. The matching layer 1617 on the supply substrate 1605 may include a solvent that may be at least partially removed, for example, by heating in an oven 1620, irradiation, or other solvent removal methods to prepare the matching layer 1617 for subsequent processing. As used herein, it should be understood that an oven is a device for providing thermal energy and heating an object. After the solvent is removed from the matching layer 1617, an optical aligner 1625 creates a matching pattern in the matching layer 1617. For example, the optical aligner 1625 may create the pattern using various lithography techniques, such as direct-write (maskless) lithography, photolithography using an optical mask and / or large exposure lens, optical master lens, or the like. In some embodiments, the matching layer 1617 may be a holographic medium, and the optical aligner 1625 may direct light onto the medium to create a direct holographic recording. In some embodiments, the substrate 1605 and matching layer 1617 may be stationary while the optical aligner 1625 produces a matching pattern in the matching layer 1617 .

[0173] After the matching layer is imprinted and cured, a first lens slot die 1630 applies a first wave plate lens layer 1632 onto the matching layer 1617. A first wave plate lens application roller 1634 may be provided to stabilize the supply substrate 1605 and the matching layer 1617 as it progresses under the first lens slot die 1615 and ensure uniform coating of the first wave plate lens layer 1632 onto the matching layer 1617. In some embodiments, the first wave plate lens layer 1632 comprises liquid crystals. The liquid crystal molecules of the liquid crystal layer may be aligned, at least in part, in a alignment determined by the patterns and / or structures in the matching layer 1617 adjacent to the first wave plate lens layer 1632. Solvent present in the first wave plate lens layer may be removed by drying and / or by passing the substrate through an oven 1637 or other heat source. An ultraviolet (UV) light source may then irradiate the first wave plate lens layer 1632 with UV light and harden the first wave plate lens layer 1632, which may polymerize the liquid crystal molecules and lock in the orientation of these molecules.

[0174] After the first waveplate lens layer 1632 is deposited and cured, an optional second waveplate lens layer 1642 may be added. A second waveplate lens slot die 1640 deposits the second waveplate lens layer 1642 as a liquid crystal polymer. A second lens application roller 1644 may be provided to stabilize the feed substrate 1605, the matching layer 1617, and the first waveplate lens layer 1632 as it progresses under the second lens slot die 1640, and ensure uniform coating of the second waveplate lens layer 1642 onto the first waveplate lens layer 1632. The second waveplate lens layer 1642 may likewise be cured by irradiation from a UV light source 1645, and the solvent may be removed by application of heat in an oven 1647. It should be understood that a single waveplate lens layer 1632 or more than two waveplate lens layers may be added by an apparatus similar to the apparatus 1600A of FIG. 18A. For example, if three waveplate lens layers are desired, apparatus 1600A may have more lens slot dies (eg, three lens slot dies) to apply the additional waveplate lens layers.

[0175] Once all of the waveplate lens layers 1632, 1642 have been applied and cured, the resulting lens substrate 1650 can be rolled up onto a lens substrate roll 1655. In some embodiments, an additional protective film 1652 is applied to one or both sides of the lens substrate 1650 to protect the surface and structure of the lens substrate 1650 during handling of the lens substrate roll 1655.

[0176] 18B-18C illustrate further examples of apparatus for roll-to-roll manufacturing of lens substrates. Similar to apparatus 1600A of FIG. 18A, apparatuses 1600B and 1600C are configured to receive a feed substrate 1605 in the form of a feed substrate roll disposed about roller 1602 and produce a lens substrate 1650, which may also be in the form of a lens substrate roll 1655, for further processing. Apparatus 1600B also includes lens slot dies 1630, 1640 to apply liquid crystal polymer waveplate lens layers 1632, 1642, which may be cured by UV light sources 1635, 1645 and / or heat sources 1637, 1647.

[0177] The apparatuses 1600B and 1600C are configured to perform an imprint alignment process in which alignment features 1662 are added to the surface of the feed substrate 1605 by imprinting. The imprint alignment may be formed using a deposition device 1660, e.g., an inkjet printer or slot die, a conformal roll template (CRT) drum 1665, and a curing device 6070, e.g., a UV light source. The deposition device 1660 may be located at various locations within the apparatuses 1600B, 1600C. In the exemplary configuration of the apparatus 1600B depicted in FIG. 18B, the deposition device 1660 is located upstream of the CRT drum 1665 and applies the imprintable material directly to the feed substrate 1605. It should be understood that the apparatus is configured to move the substrate in a particular direction (e.g., from the roller 1602 to the substrate roll 1655), and thus the terms "upstream" and "downstream" refer to points in the substrate path. "Upstream" refers to a location opposite to a direction in which the apparatus is configured to move a substrate, while "downstream" refers to a location in the direction in which the apparatus is configured to move a substrate.

[0178] In the configuration shown in FIG. 18B, as the feed substrate 1605 passes the deposition device 1660, the deposition device 1660 deposits a layer or pattern of droplets onto the feed substrate 1605. In some embodiments, the pattern of droplets may form a continuous layer of material to be imprinted, e.g., resist material. A matching print roller 1664 may be provided to stabilize the feed substrate 1605 as it progresses past the deposition device 1660 and provide a stable surface to enable the deposition device 1660 to deposit material onto the feed substrate 1605. The side of the feed substrate 1605 bearing the deposited material then contacts a CRT drum 1665. The surface of the CRT drum 1665 comprises a pattern of physical features that imprint the pattern into the imprint material deposited on the surface of the feed substrate 1605. 18C , the deposition device 1660 may be positioned to deposit the imprintable material directly onto the CRT drum 1665. In this case, the imprintable material on the surface of the CRT drum 1665 may be applied to the surface of the supply substrate 1605 and imprinted and adhered to the supply substrate 1605 as the CRT drum 1665 contacts the supply substrate 1605.

[0179] The UV light source 1670 cures the imprinted material such that the negative trends of the features of the CRT drum 1665 surface remain as alignment features 1662 on the feed substrate 1605. When the liquid crystal polymer for the first waveplate lens layer 1632 is applied to the feed substrate 1605 over the alignment features 1662 in the first lens slot die 1630, the alignment features 1662 may induce alignment of the crystals of the liquid crystal polymer prior to the curing caused by the energy source 1635, e.g., a UV light source. In some embodiments, the imprint layer formation applied by the apparatus 1600B may enable continuous operation of the apparatus 1600B (e.g., non-stop processing of an entire roll of feed substrate 1605 to lens substrate 1650) because the imprint alignment process may be operated continuously without requiring sections of the feed substrate 1605 to be paused, e.g., for stationary optical alignment.

[0180] In some embodiments, the roll-to-roll manufacturing process described and depicted with reference to Figures 18A-18C may be performed in two or more sub-processes, for example using different manufacturing equipment. With reference to Figure 18D, an apparatus 1600D may perform a first roll-to-roll manufacturing process to produce an intermediate substrate 1607 having alignment features from a supply substrate 1605. With reference to Figure 18E, an apparatus 1600E may subsequently perform a second roll-to-roll manufacturing process to produce a lens substrate 1655 having a deposited liquid crystal layer using the intermediate substrate 1607.

[0181] 18D, an apparatus 1600D is configured to perform an imprint alignment process similar to the portion of the imprint alignment process of FIGS. 18B and 18C. The apparatus 1600D is configured to receive a feed substrate 1605 in the form of a feed substrate roll disposed about a feed substrate roller 1602. In some embodiments, the feed substrate roll includes a protective film 1610, which may be removed before alignment features are formed on the feed substrate 1605. The feed substrate 1605 progresses through the apparatus 1600D supported by a number of feed substrate rollers 1676, which may be located, for example, at points where the path of the feed substrate 1605 changes direction. The rollers 1676 facilitate movement of the feed substrate 1605 along the substrate path from the substrate feed roller 1602 to rollers 1607 around which the intermediate substrate is wound to form an intermediate substrate roll. As used herein, a substrate supply roll is a roll of supply substrate 1605 before the formation of alignment features thereon, which may be wrapped around substrate supply roller 1602, and an intermediate substrate roll is a roll of supply substrate 1605 after the formation of alignment features thereon, which may be wrapped around roller 1607.

[0182] The apparatus 1600D further includes a template 1672 (e.g., a conformal roll template), which may be a closed or continuous loop formed of a flexible material having an imprint template pattern on its surface. Preferably, rollers 1674 support, move, and provide tension for the template 1672. Thus, the rollers 1674 define a closed template path or travel loop for the template 1672. In some embodiments, the template 1672 may include a repeating template pattern similar to the template pattern present on the surface of the CRT drum 1665 of Figures 18B and 18C. It should be understood that the template paths abut or directly abut in portions of the substrate paths, and the pattern may be transferred from the template 1672 to the substrate 1605 at the location where these two paths meet (the imprint portion of the template path).

[0183] The closed loop template 1672 may advantageously provide advantages over a CRT drum arrangement. For example, it should be understood that a CRT drum may have a template wrapped around its surface with the ends of the template formed on a sheet of material with the ends spliced ​​together on the drum. At the point where the ends are spliced, there may be an overlap between the ends. Undesirably, this overlap does not provide acceptable imprint results due to, for example, height differences between the overlap and other areas of the template. As a result, the overlap undesirably reduces the yield and / or throughput of the lens structures formed in the substrate 1605. Advantageously, the template 1672 may also have an overlap area, but the length of the template loop 1672 is typically longer than the circumference of the CRT drum. As a result, the percentage of the template 1672 occupied by the overlap is less than the percentage of the overlap area with the CRT drum. This may improve the yield and / or throughput relative to a typical CRT drum. Further, in some embodiments, the length of the template 1672 may be increased, as desired, by appropriate extension and / or routing of the template 1672 along the path defined by the rollers 1674. It should be understood that the length of the template associated with a CRT drum is not very easily manipulated, as it depends on the size of the drum. In addition, as shown in Figures 18B and 18C, the CRT drum 1665 contacts the substrate along its curved surface, which may be subject to tension changes at different contact points with the substrate, and because the drum surface is curved, may not provide the same high fidelity for transferring an imprint pattern as contact along a flat area as provided by the template 1672.

[0184] 18D, at least one deposition device 1660 is positioned above the feed substrate 1605 and / or the conformal roll template 1672. Similar to the deposition device 1660 of FIGS. 18B and 18C, the deposition device 1660 can be any suitable device for depositing material onto one or both of the conformal roll template 1672 and the feed substrate 1605, such as an inkjet printer, a slot die, or the like. The deposited material can be a selectively definable material, such as an imprint resist, in some embodiments. Preferably, the feed substrate 1605 and the template 1672 travel in the same direction and at the same speed along at least a portion of their path through the apparatus 1600D. In some embodiments, adjacent portions of the feed substrate 1605 and the template 1672 travel paths are located downstream of the deposition device 1660 such that the deposited material can be imprinted by the template features of the conformal roll template 1672. An energy source 1670 (e.g., a light source such as a UV light source) is positioned along the adjacent portion to cure the imprinted material such that the negative trend of the template 1672 surface features remain on the feed substrate 1605 after contact with the CRT drum 1665 as one or more matching features similar to those depicted in Figures 18B and 18C. In some embodiments, the adjacent portion is preferably a linear portion of the path of the display substrate 1605 such that both the conformal roll template 1672 and the feed substrate 1605 are substantially flat as the deposited material is imprinted and cured. The imprinting and curing of the negative trend on the feed substrate 1605 results in an intermediate substrate. The imprinted side of the intermediate substrate may then be coated with a protective film 1608 before the intermediate substrate is rolled up on roller 1607 to complete the first portion of the roll-to-roll manufacturing process.

[0185] 18E, a second portion of the roll-to-roll manufacturing process may be used to form a waveplate layer on the intermediate substrate to produce a finished lens substrate 1650. Apparatus 1600E, in some embodiments, is configured to receive an intermediate substrate formed using apparatus 1600D. In some embodiments, apparatus 1600E may be located at a different location from apparatus 1600D, and the intermediate substrate may be transported in roll form to a location of apparatus 1600E to be converted to lens substrate 1650. In apparatus 1600E, the intermediate substrate may be unrolled on intermediate substrate roller 1607′. Any protective film 1608 may also be removed during this unrolling. 18A-18C, after the protective film 1608 is removed from the intermediate substrate, a first wave plate lens layer 1632 may be deposited by a first wave plate lens layer dispenser 1615 (e.g., a slot die), which may then be cured using a heat source 1637 (e.g., an oven) and / or a light source 1635 (e.g., a UV light source). A second wave plate lens layer may similarly be deposited by a second wave plate lens layer dispenser 1640 (e.g., a second slot die), which may then be cured using a second heat source 1647 (e.g., a second oven) and / or a second light source 1645 (e.g., a second UV light source). The resulting lens substrate 1650 may be rolled up onto a lens substrate roller 1655. In some embodiments, an additional protective film 1652 may be applied to one or both sides of the lens substrate 1650 to protect the surface and structure of the lens substrate 1650 during handling by the lens substrate roller 1655 .

[0186] 19A and 19B illustrate additional exemplary systems for sheet manufacturing of lens substrates for adaptive lens assemblies. Similar to the configurations of FIGS. 18A-18E, systems 1700A and 1700B are configured to apply one or more thin waveplate lens layers, such as liquid crystal polymer waveplate lens layers, to a feed substrate to form a lens substrate. The processes applied in FIGS. 19A and 19B correspond to the processes applied in FIGS. 18A-18E, respectively. Systems 1700A and 1700B differ from apparatuses 1600A, 1600B, 1600C, 1600D, and 1600E primarily in that systems 1700A and 17000B are configured for a sheet-based manufacturing process rather than the roll-to-roll manufacturing process described with reference to FIGS. 18A-18E. For example, substrate sheets 1705, rather than rolls, may be utilized for processing. In various embodiments, the sheets may be square or rectangular and may have dimensions of 6 inches to 36 inches on each side.

[0187] The system 1700A receives a feed substrate sheet 1705, which may be, for example, a quarter wave plate substrate having a mesh or other array of conductive material on one side of the substrate. The system 1700A includes an optical aligner 1710, a matching layer applicator 1715, a first wave plate lens layer applicator 1720, a second wave plate lens layer applicator 1725, a UV light source 1730, and an oven 1735, which may be similar to the deposition and curing device of the apparatus 1600A of FIG. 18A. The matching layer applicator 1715 and the wave plate lens layer applicators 1720, 1725 may each include a slot die and / or other mechanism for depositing a layer of material onto the feed substrate sheet 1705. The feed substrate sheet 1705 progresses along a process path 1707 and through other components of the system 1700A. The optical aligner 1710 is configured to advance along an axis 1712 transverse to the process path 1707 such that the optical aligner may apply one or more alignment structures to the feed substrate sheet 1705 and / or the alignment layer material 1715 by photolithography, direct write methods, holographic recording, or other optical processes. In some embodiments, the optical aligner 1710 may apply the alignment structures while the feed substrate sheet 1705 is in a stationary position at least partially intersecting the axis 1712.

[0188] The system 1700B of FIG. 19B employs a similar sheet processing method as shown in FIG. 19A. The system 1700B is configured to receive a supply substrate sheet 1705 that has been previously prepared with alignment features 1708. For example, the alignment structures 1708 can be applied by a jet and flash process similar to the imprint alignment process described with reference to FIG. 18B (which involves depositing a resist layer and patterning the resist layer by imprinting to form the alignment structures 1708). It should be understood that the alignment structures 1708 are represented diagrammatically and may have other arbitrary shapes of features and more complex arrangements than those depicted. Examples of alignment structures are disclosed in U.S. Provisional Patent Application No. 62 / 424,341, filed November 18, 2016, and U.S. Provisional Patent Application No. 62 / 518,539, filed June 12, 2017, both of which are incorporated herein by reference in their entirety. Thus, the alignment features 1708 can determine, at least in part, the orientation of the crystals in the liquid crystal polymer applied by the first wave plate lens layer applicator 1720.

[0189] 20A and 20B illustrate an exemplary system for spin-coat fabrication of a lens substrate for an adaptive lens subassembly. Similar to systems 1700A and 1700B of FIGS. 19A and 19B, systems 2000A and 2000B are configured to apply one or more thin waveplate lens layers, such as liquid crystal waveplate lens layers, to discrete sections of a feed substrate to form a lens substrate. The processes applied in FIGS. 20A and 20B correspond to those applied in FIGS. 19A and 19B, respectively. Systems 2000A and 2000B differ from systems 1700A and 1700B primarily in that systems 2000A and 2000B are configured to form a waveplate lens layer on a generally circular feed substrate 2005 rather than the rectangular feed substrate sheet 1705 depicted in FIGS. 19A and 19B. For example, a roll of supply substrate may be cut into supply substrate sheets 2005 prior to entering systems 2000A, 2000B, and custom substrate sheets may be obtained as circular sheets 2005. In various embodiments, supply substrate wafers 2005 may have a diameter between 100 mm and 500 mm. For example, supply substrate wafers 2005 may be standardized wafer sizes such as 150 mm, 200 mm, 300 mm, 450 mm, etc.

[0190] The system 2000A receives a feed substrate 2005, which may be, for example, a quarter wave plate substrate having a mesh or other array of conductive material preformed on one side of the substrate 2005. Similar to the system 1700A of FIG. 19A, the system 2000A includes an optical aligner 2010, a matching layer applicator 2015, a first wave plate lens layer applicator 2020, a second wave plate lens layer applicator 2025, a UV light source 2030, and an oven 2035, some or all of which may be located on a gantry 2040. The gantry may be movable along a gantry axis 2042 such that the gantry 2040 may advance, partially or in whole, to any of a variety of positions across the rotating feed substrate wafer 2005. The optical aligner 2010 may be configured to advance along an aligner axis 2012 on the gantry 2040. The matching layer applicator 1715 and the waveplate lens layer applicators 1720, 1725 may each include a dispensing mechanism configured to deposit a portion of the liquid material onto the supply substrate 2005. For example, the dispensing mechanism may be a spin-coating deposition device. In some embodiments, the dispensing mechanism may apply the liquid material to the center of the supply substrate wafer 2005 such that spinning of the supply substrate 2005 distributes the liquid radially outward across the surface of the supply substrate wafer 2005 by centrifugal force.

[0191] The feed substrate wafer 2005 rotates about the center of the substrate 2005 while the gantry 2040 passes along the gantry axis 2042 over the wafer 2005. In some embodiments, the gantry 2040 may pass over the feed substrate wafer 2005 several times. For example, on the first pass, the matching layer applicator 2015 may apply a liquid matching layer, which is dispersed by centrifugal force and cured as the UV light source 2030 and / or oven 2035 pass over the wafer 2005. The optical aligner 2010 may then pass over the wafer 2005 and optically create one or more matching structures in the matching layer before the waveplate lens layer is applied by the first and second waveplate lens layer applicators 2020, 2025. It should be understood that the matching and waveplate lens layers may each be deposited by spin coating, by deposition of material toward the center of the substrate 2005, and by distribution of material over the substrate by feeding the substrate.

[0192] The system 2000B of FIG. 20B employs a similar sheet processing method as shown in FIG. 20A. The system 2000B is configured to receive a prepared feed substrate wafer 2005 with alignment features 2008, which may be similar to the alignment features 1708 of FIG. 19B. For example, the alignment structures 2008 can be applied by an inkjet deposition and imprint process in which an imprint material is deposited on the substrate 2005, the material is physically imprinted with a pattern (e.g., using a mold or imprint reticle), the imprinted material is solidified or cured, and the mold or imprint reticle is removed. Thus, the alignment features 2008 can determine, at least in part, the orientation of the crystals in the liquid crystal polymer applied by the first waveplate lens layer applicator 2020. One or more waveplate lenses may be formed on the alignment features 2008 using one or more waveplate lens layer applicators 2020, 2025, as described above with respect to FIG. 20A.

[0193] Referring together to FIGS. 18A-20B, each of the described apparatuses, systems, and methods may produce rolls or sheets of lens substrates that are larger and / or differently shaped than the adaptive lens assemblies that will be incorporated into a display device (e.g., adaptive lens assemblies 1004, 1008 as shown in FIG. 10). For example, a roll or sheet of lens substrate may contain enough lens substrates to form multiple adaptive lens assemblies or subassemblies. Thus, the adaptive lens assemblies, subassemblies, and / or substrates may be split, shaped, and / or singulated at some point during the manufacturing process. In one example, a roll of lens substrate may be cut into sheets. Cell walls (e.g., cell walls 1418 as shown in FIGS. 17C and 17D) may be printed onto the sheet in the desired shape of the adaptive lens assembly. Liquid crystals may then be added and quarter wave plate substrates bonded to the cell walls as described herein to form sheets of adaptive lens subassemblies. Alternatively, sections of the substrate may be separated into lens substrates for individual adaptive lens subassemblies before the liquid crystals are added. When a sheet of adaptive lens subassemblies is formed, the sheet may then be separated into individual adaptive lens subassemblies, which may then be combined in multiple layers to form a completed adaptive lens assembly. Method for forming wire mesh and electrode patterns - Patents.com

[0194] As discussed above, a variety of methods may be employed to form the electrode patterns or wire meshes 1420 disclosed herein.

[0195] 21A-21C illustrate an example of a process for forming a pattern of conductive material by directional etching. A metal layer 1420 is deposited on a substrate 1416, and a resist layer 2100 is deposited on the metal layer 1420 (e.g., by inkjet deposition). The resist layer 2100 is subsequently patterned (e.g., by imprinting and subsequent solidification by UV exposure). The patterned resist layer 2100 can then be used as a mask for directional or anisotropic etching of an underlying metal layer to define patterned conductive features 1420, which can be electrodes as disclosed herein. It should be understood that the substrate 1416 may correspond to the substrates 1605, 1705, 2005 discussed with reference to various figures herein.

[0196] 22A-22C illustrate an example of a process for forming a pattern of conductive material using a solvent soluble "lift-off" layer. A solvent soluble layer 2102 is deposited on the substrate 1416, and a resist layer 2100 is deposited on the solvent soluble layer 2102 (e.g., by inkjet deposition). The resist layer 2100 is subsequently patterned (e.g., by imprinting and subsequent solidification by UV exposure). The patterned resist layer 2100 may include a pattern of openings 2101a and may be used as a mask for wet etching of the solvent soluble underlayer layer 2102, thereby opening volumes into which a metal (e.g., silver) is deposited using a blanket deposition as shown in FIG. 22B. It should be understood that blanket deposition may include chemical vapor deposition (CVD or AP-CVD), physical vapor deposition (PVD), slot-die deposition, inkjet printing, doctor blade deposition, etc. In some embodiments, the solvent soluble layer is formed from a water soluble material, and the wet etching includes exposure to water. In some other embodiments, the solvent soluble layer is formed from PMMA and the wet etch involves exposure to acetone or toluene. After metal deposition, referring to FIG. 22C, the entire structure is again exposed to a solvent, which removes or easily lifts off the solvent soluble layer 2102, leaving the deposited metal in the pattern dictated by the originally patterned resist layer 2100.

[0197] 23A-23C illustrate an example of a process for forming a pattern of a conductive material using a seed layer. A resist layer 2100 is deposited (e.g., by inkjet deposition) on the substrate 1416, and a solvent soluble layer 2102 is deposited on the resist layer 2100. The resist layer 2100 and the solvent soluble layer 2102 are patterned (e.g., by imprinting and subsequent solidification by UV exposure) to have a shared open volume 2101a. A conductive seed layer (e.g., a metal layer) is blanket deposited (e.g., by CVD or PVD) over the entire structure. The solvent soluble layer 2102 is subsequently exposed to a solvent, thereby allowing removal of a portion of the seed layer 2104' above the solvent soluble layer 2102. A conductive metal is then selectively deposited in the openings 2101a, for example, by electroplating.

[0198] 24A-24C illustrate another example of a process for forming a pattern of conductive material using a seed layer. A conductive seed layer 2104 is deposited (e.g., by CVD or PVD) on the substrate 1416, and a resist layer 2100 is deposited on the seed layer 2104. The resist layer 2100 is patterned (e.g., by imprinting and subsequent solidification by UV exposure), for example, to define a volume 2101a. The volume 2101a may be extended downwards to expose the seed layer 2104 by etching, for example, using an anisotropic etch selective with respect to the material forming the resist layer 2100. A conductive metal is then selectively deposited in the openings 2101a, for example, by electroplating.

[0199] 25A-25C illustrate an example of a process for forming a pattern of conductive material by deposition of a suspension of metal material into openings in a patterned layer. A resist layer 2100 is deposited (e.g., by CVD or PVD) on a substrate 1416 and patterned (e.g., by imprinting and subsequent solidification by UV exposure) to define, for example, volume 2101a. A metal-containing solution or suspension 1420'' is then deposited into the openings 2101a, for example, by inkjet deposition, slot-die deposition, etc. The liquid in the suspension or solution may then be removed, for example, by exposure to heat (e.g., sintering), leaving the metal in the openings. In some embodiments, the solution or suspension 1420'' may be exposed to a timed wet or dry etchant to remove an upper portion of the deposited metal-containing layer extending above the openings 2101a, and optionally not exposed to heat to drive the liquid out of the suspension or solution. In some embodiments, the resist 2100 may then be removed. In some other embodiments, the resist may be retained to provide additional mechanical and structural stability.

[0200] 26A-26F illustrate examples of top-down views of patterns of conductive material. In some embodiments, the conductive material 1420 in each of FIGS. 26A-26F may be formed by the methods described above with reference to FIGS. 21A-25C. In general, the conductive material 1420 may be arranged in various shapes, patterns, paths, and / or orientations along the substrate. In some embodiments, the arrangement of the conductive material 1420 may be selected to provide a sufficiently uniform electric field across the liquid crystal material disposed adjacent to the substrate. In various non-limiting examples, the arrangement of conductive material 1420 may include a square or rectangular array (e.g., FIG. 26A), an array of parallel wires connected by one or more transverse wires (e.g., FIG. 26B), non-overlapping serpentine wires (e.g., FIG. 26C), multiple overlapping serpentine wires (e.g., FIG. 26D), generally spiral wires (e.g., FIG. 26E), a parallelogram array (e.g., FIG. 26F), or various other arrangements of straight and / or curved elongated wires of material. The ends of the various wires of conductive material 1420 may be in contact with other circuitry configured to selectively apply a voltage difference across conductive material 1420 to generate an electric field.

[0201] 27A-27D, examples of cross-sectional side views of lines of conductive material are illustrated. In some embodiments, the methods and layers depicted in FIG. 27A-27D may be used to form various shapes and / or layers of, for example, conductive material 1420 or other materials. For example, additional layers may be useful in forming an anti-reflective coating. For example, a layer of cap material 1421 (e.g., an optically transmissive material) may be applied over at least a portion of the conductive material 1421. The thickness of the cap material 1421 may be selected to enable the cap material 1421 to function as an anti-reflective coating, for example, to provide destructive interference in a desired range of wavelengths.

[0202] As shown in Figure 27A, in some embodiments, the conductive material 1420 can be applied to a desired shape by angled deposition. In Figure 27A, the patterned layer 2100 includes a plurality of features that protrude away from the substrate 1416, 1605, 1705, 2005. The angled deposition of the conductive material 1420, such as silver or the like, can result in a configuration in which one side of the protruding features is substantially covered while other portions of the patterned layer 2100 remain exposed, for example, providing a relatively large cross-sectional area for electrical current to flow.

[0203] As shown in FIG. 27B, a cap material 1421 may be applied to the layer of conductive material 1420. For example, the cap material 1421 may be an additional metal such as chromium or equivalent, an ionic compound such as MgF2, SiO2, TiO2, or equivalent, or any other cap material that may be deposited on the conductive material 1420 to provide the desired electrical and / or optical properties. FIG. 27C depicts a similar arrangement to FIG. 27B, where an additional seed layer 2104 or adhesion layer is provided between the conductive material 1420 and the substrate 1416, 1605, 1705, 2005. For example, a seed layer may be left from the formation of the conductive material 1420 using the process of FIGS. 23A-24C. As shown in FIG. 27D, the conductive material 1420 may be formed on the substrate 1416, 1605, 1705, 2005 in various shapes. For example, the cross-sectional profile of the conductive material 1420 may be a rectangular profile 1420a, a triangular profile 1420b, a rounded profile 1420c, a trapezoidal profile 1420d, or any other desired profile shape. Additional Considerations

[0204] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be apparent that various modifications and changes can be made therein without departing from the broader spirit and scope of the invention. The specification and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.

[0205] Indeed, it should be understood that the systems and methods of the present disclosure each have several innovative aspects, none of which is solely responsible for 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 the present disclosure.

[0206] Certain features described herein in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a combination and may even be initially claimed as such, one or more features from the claimed combination may in some cases be deleted from the combination, and the claimed combination may be directed to a subcombination or variation of the subcombination. No single feature or group of features is necessary or essential to every embodiment.

[0207] In particular, it should be understood that conditional statements used herein, such as "can," "could," "might," "may," "eg," and the like, are generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not, unless specifically stated otherwise or understood otherwise within the context as used. Thus, such conditional statements are generally not intended to suggest 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 determining whether or not those features, elements, and / or steps should be included or performed in any particular embodiment, with or without authorial input or prompting. The terms "comprise," "include," "have," and the like, are synonymous and used inclusively in a non-limiting manner and do not exclude additional elements, features, acts, operations, etc. Also, the term "or" is used in its inclusive sense (and not its exclusive sense), thus, for example, when used 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, should be interpreted to mean "one or more" or "at least one," unless otherwise specified. Similarly, although operations may be depicted in the figures in a particular order, it should be recognized that such operations need not be performed in the particular order depicted, or in sequential order, or that all of the depicted operations need not be performed to achieve desirable results. Furthermore, the figures may diagrammatically depict one or more exemplary processes in the form of a flow chart. However, other operations not depicted may also be incorporated within the diagrammatically depicted exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the depicted operations. In addition, operations may be rearranged or reordered in other embodiments.In some situations, multitasking and parallel processing may be advantageous. Furthermore, 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 program components and systems described may generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

[0208] Thus, the claims are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with the present disclosure, the principles and novel features disclosed herein.

Claims

[Claim 1] The invention described in this specification.

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