Broadband adaptive lens assembly for augmented reality display

Abstract

A display device includes a waveguide configured to guide light in a lateral direction parallel to an output surface of the waveguide. The waveguide is further configured to couple out the guided light through the output surface. The display device additionally includes a broadband adaptive lens assembly configured to couple in and diffract coupled-out light from the waveguide therein. The broadband adaptive lens assembly comprises a first waveplate lens comprising a liquid crystal (LC) layer arranged such that the waveplate lens has a birefringence (Dn) that varies in a direction radially outward from a central region of the first waveplate lens, and is configured to diffract the coupled light at a diffraction efficiency greater than 90% in a wavelength range including at least 450 nm to 630 nm. The broadband adaptive lens assembly is configured to selectively switch between a plurality of states having different focal powers.

Description

[0001] This application is a divisional application of the patent application with international application number PCT / US2018 / 057604, international application date October 25, 2018, Chinese national application number 201880083678.7, and title “Wideband Adaptive Lens Assembly for Augmented Reality Display”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 577,672, filed on October 26, 2017, and entitled “BROADBANDADAPTIVE LENS ASSEMBLY FOR AUGMENTED REALITY DISPLAY,” the entire contents of which are incorporated herein by reference.

[0004] Incorporation by Reference

[0005] This application incorporates by reference the entire contents of each of the following patent applications: U.S. Application Serial No. 14 / 555,585, filed on November 27, 2014, published as U.S. Publication 2015 / 0205126 on July 23, 2015; U.S. Application Serial No. 14 / 690,401, filed on April 18, 2015, published as U.S. Publication 2015 / 0302652 on October 22, 2015; U.S. Application Serial No. 14 / 212,961, filed on March 14, 2014, now U.S. Patent 9,417,452, published on August 16, 2016; and U.S. Application Serial No. 14 / 331,218, filed on July 14, 2014, published as U.S. Publication 2015 / 0309263 on October 29, 2015. Technical Field

[0006] The present disclosure relates to display systems and, more particularly, to augmented and virtual reality display systems. Background Art

[0007] 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 looks or can be perceived as real. Virtual reality or "VR" scenarios typically involve presenting digital or virtual image information opaquely to otherwise actual real-world visual input; augmented reality or "AR" scenarios typically involve presenting digital or virtual image information as an enhancement to the visualization of the actual world around the user. A mixed reality or "MR" scenario is an AR scenario, and typically involves virtual objects that are integrated into and responsive to the natural world. For example, in an MR scenario, AR image content may be occluded by objects in the real world or perceived as interacting with objects in the real world.

[0008] refer to Figure 1 , shows an augmented reality scene 10 in which a user of 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 AR technology also perceives that he "sees" "virtual content," such as a robot statue 40 standing on the real-world platform 30, and a cartoon-like avatar character 50 flying by that appears to be an avatar of a bumblebee, even though these elements 40, 50 do not exist in the real world. Due to the complexity of the human visual perception system, it is extremely challenging to produce AR technology that facilitates comfortable, natural, and rich presentation of virtual image elements from other virtual or real-world image elements.

[0009] The systems and methods disclosed herein address various challenges associated with AR and VR technologies. Summary of the invention

[0010] In one aspect, a display device includes a waveguide configured to guide light in a lateral direction parallel to an output surface of the waveguide. The waveguide is further configured to outcouple the guided light through the output surface. The display device further includes a broadband adaptive lens assembly configured to incouple the outcoupled light from the waveguide and diffract the outcoupled light from the waveguide therein. The broadband adaptive lens assembly includes a first waveplate lens, the first waveplate lens includes a liquid crystal (LC) layer, the liquid crystal (LC) layer is arranged so that the waveplate lens has a birefringence (Δn) that varies in a direction radially outward from a central region of the first waveplate lens, and is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% within a wavelength range including at least 450nm to 630nm. The broadband adaptive lens assembly is configured to selectively switch between a plurality of states having different optical powers.

[0011] On the other hand, a broadband adaptive lens assembly for a display device includes a first wave plate lens, which includes a liquid crystal (LC) layer, the liquid crystal layer having LC molecules arranged so that the first wave plate lens has a birefringence (Δn) that varies in a direction radially outward from a central area of ​​the first wave plate lens, and is configured to diffract light with a diffraction efficiency greater than 90% over a wavelength range spanning at least 450nm to 630nm. The broadband adaptive lens assembly further includes a switchable wave plate, which is configured to be electrically activated and deactivated. The broadband adaptive lens assembly is configured to selectively switch between at least two lens states. The two lens states include: a first lens state, which is configured to apply a first lens effect according to a first optical focal length and change the polarization of light passing through the broadband adaptive lens assembly; and a second lens state, which is configured to apply a second lens effect according to a second optical focal length and maintain the polarization of light passing through the broadband adaptive lens assembly.

[0012] On the other hand, a broadband adaptive lens assembly for a display device includes a first wave plate lens, which includes a liquid crystal (LC) layer formed on a substrate. The LC layer has LC molecules arranged so that the first wave plate lens has a birefringence (Δn) that varies in a direction radially outward from a central region of the LC layer, and is configured to diffract light with a diffraction efficiency greater than 90% over a wavelength range spanning at least 450nm to 630nm. The LC molecules closest to the substrate among the LC molecules have substantially the same orientation direction at different positions at the same radius relative to the central region. The broadband adaptive lens assembly is configured to selectively switch between at least two lens states. The first lens state is configured to apply a first lens effect according to a first optical focal length and change the polarization of light passing through the broadband adaptive lens assembly. The second lens state is configured to apply a second lens effect according to a second optical focal length and maintain the polarization of light passing through the broadband adaptive lens assembly.

[0013] On the other hand, an integrated broadband adaptive lens assembly for a display device includes a first electrode, a second electrode, and a liquid crystal (LC) layer stack between the first electrode and the second electrode. The LC layer stack includes a switchable liquid crystal (LC) layer, which includes unpolymerized LC molecules between a first polymerized LC layer and a second polymerized LC layer, each of which includes polymerized LC molecules. LC molecules in the switchable LC layer adjacent to LC molecules in the first polymerized LC layer are generally elongated in a first direction. LC molecules in the switchable LC layer adjacent to LC molecules in the second polymerized LC layer are generally elongated in a second direction intersecting the first direction. The LC molecules included in the switchable LC layer are configured so that under a first voltage condition across the first electrode and the second electrode, the polarization of incident light passing therethrough is maintained, and under a second voltage condition across the first electrode and the second electrode, the polarization of incident light passing therethrough is changed.

[0014] In another aspect, a display device includes a pair of adaptive lens assemblies located in an optical path. Each of the adaptive lens assemblies includes a corresponding switchable wave plate configured to diffract light with a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm and switch between a first state and a second state to selectively change the polarization state of light passing therethrough. The adaptive lens assemblies have optical powers of opposite signs.

[0015] On the other hand, an adaptive lens assembly includes one or more wave plate lenses and one or more switchable wave plates aligned in an optical path. Each of the one or more wave plate lenses is configured to diffract outcoupled light with a diffraction efficiency greater than 90% in a wavelength range including at least 450nm to 630nm, and change the polarization state of the light passing therethrough, thereby providing a first optical focal length for light having a first polarization, and providing a second optical focal length for light having a second polarization. Each of the one or more switchable wave plates is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% in a wavelength range including at least 450nm to 630nm, and is selectively switchable between a first state configured to allow light to pass therethrough without changing the polarization state of the light and a second state configured to change the polarization state of the light passing therethrough.

[0016] On the other hand, a wearable augmented reality head-mounted display system includes: a light modulation system configured to output light to form an image; a head-mounted frame; one or more waveguides attached to the frame and configured to receive light from the light modulation system; and a pair of adaptive lens assemblies, wherein the one or more waveguides are disposed between the adaptive lens assemblies. Each of the adaptive lens assemblies includes one or more wave plate lenses, the one or more wave plate lenses configured to diffract outcoupled light with a diffraction efficiency greater than 90% in a wavelength range including at least 450nm to 630nm, and provide a first optical focal length for light having a first polarization, and provide a second optical focal length for light having a second polarization, each of the adaptive lens assemblies further includes one or more switchable wave plates located in an optical path, wherein each of the one or more switchable wave plates is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% in a wavelength range including at least 450nm to 630nm, and selectively change the polarization state of light passing therethrough. The adaptive lens assembly is configured to provide a corresponding optical focal length that is adjustable when a corresponding electrical signal is applied.

[0017] On the other hand, a method of integrating a broadband adaptive lens assembly includes forming a lower stack and an upper stack, the lower stack including a first electrode layer formed on a first substrate, a first alignment layer formed on the first electrode layer, and a first polymerized LC layer located on the first alignment layer. The upper stack includes a second electrode layer formed on a second substrate, a second alignment layer formed on the second electrode, and a second polymerized LC layer located on the second alignment layer. The method further includes stacking the upper stack and the lower stack after forming the lower stack and the upper stack so that the first polymerized LC layer and the second polymerized LC layer face each other, wherein the stacking includes forming a spacer to form a gap between the upper stack and the lower stack. The method further includes filling the gap with unpolymerized LC molecules to form a switchable liquid crystal (LC) layer. Forming the switchable LC layer includes self-aligning LC molecules in the switchable LC layer adjacent to LC molecules in the first polymerized LC layer to be elongated approximately in a first direction, and self-aligning LC molecules in the switchable LC layer adjacent to LC molecules in the second polymerized LC layer to be elongated approximately in a second direction intersecting the first direction.

[0018] In another aspect, a method for preparing a broadband wave plate lens assembly includes providing a transparent substrate and forming an alignment layer on the transparent substrate. The alignment layer is configured to align liquid crystal (LC) molecules formed thereon according to a wave plate lens pattern. The method further includes forming an LC layer on the alignment layer. LC molecules in the LC layer that are immediately adjacent to the alignment layer are aligned according to the wave plate lens pattern, in which LC molecules in the LC layer located at a given radius relative to a central area of ​​the wave plate lens pattern have elongation directions that are aligned substantially in the same direction. The LC layer is configured to diffract light with a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm. The broadband adaptive lens assembly is configured to selectively switch between a plurality of states having different optical powers.

[0019] In another aspect, a head-mounted display system is configured to project light into a user's eyes to display augmented reality image content in the user's field of view. The head-mounted display system includes a frame configured to be supported on the user's head. The display system further includes an eyepiece disposed on the frame. At least a portion of the eyepiece is transparent and is disposed in a position in front of the user's eyes when the user wears the head-mounted display, so that the transparent portion transmits light from the environment in front of the user to the user's eyes to provide a view of the environment in front of the user. The eyepiece is configured to emit light into the user's eyes to display augmented reality image content to the user's field of view. At least one switchable lens assembly includes a diffractive liquid crystal lens assembly, the diffractive liquid crystal lens assembly including a twisted nematic switchable lens. The twisted nematic switchable lens includes an active layer of twisted nematic liquid crystal; a first polymerized liquid crystal layer adjacent to the active layer of the twisted nematic liquid crystal; and a second polymerized liquid crystal layer adjacent to the active layer of the twisted nematic liquid crystal. The active layer of the twisted nematic liquid crystal is disposed between the first polymerized liquid crystal layer and the second polymerized liquid crystal layer. The nematic switchable lens further includes a first electrode and a second electrode, which are configured to apply an electric field to the active layer of the twisted nematic liquid crystal. The first electrode and the second electrode are located on opposite sides of the active layer and the first polymerized liquid crystal layer and the second polymerized liquid crystal layer, so that the active layer and the first polymerized liquid crystal layer and the second polymerized liquid crystal layer are arranged between the first electrode and the second electrode. The head-mounted display further includes an electronic device, which is configured to change the optical focal length of the switchable lens by applying an electrical signal to the electrodes. The at least one switchable lens assembly is configured to transmit light from the environment in front of the user to the user's eyes.

[0020] On the other hand, a head-mounted display system is configured to project light into the eyes of a user to display augmented reality image content in the user's field of view. The head-mounted display system includes a frame configured to be supported on the head of the user. The system further includes an eyepiece, which is disposed on the frame. At least a portion of the eyepiece is transparent and is disposed in a position in front of the user's eyes when the user wears the head-mounted display, so that the transparent portion transmits light from the environment in front of the user to the user's eyes to provide a view of the environment in front of the user. The eyepiece is configured to emit light into the user's eyes to display augmented reality image content to the user's field of view. The system further includes at least one switchable lens assembly, which includes a diffractive liquid crystal lens assembly. The diffractive liquid crystal lens assembly includes: an active layer, which includes a twisted nematic liquid crystal diffractive lens; a first retarder and a second retarder, which include polymerized liquid crystals located on opposite sides of the active layer; and a first electrode and a second electrode, which are configured to apply an electric field to the active layer of the twisted nematic liquid crystal, the first electrode and the second electrode being located on opposite sides of the active layer. The system further includes an electronic device configured to change the optical focal length of the switchable lens by applying an electrical signal to the electrode, wherein at least one of the switchable lenses is configured to transmit light from the environment in front of the user to the user's eyes.

[0021] On the other hand, a head-mounted display system is configured to project light into the eyes of a user to display augmented reality image content in the user's field of view. The head-mounted display system includes a frame configured to be supported on the head of the user. The system further includes an eyepiece, which is disposed on the frame. At least a portion of the eyepiece is transparent and is disposed in a position in front of the user's eyes when the user wears the head-mounted display, so that the transparent portion transmits light from the environment in front of the user to the user's eyes to provide a view of the environment in front of the user. The eyepiece is configured to emit light to the user's eyes to display augmented reality image content to the user's field of view. The system further includes at least one switchable lens assembly, which includes a plurality of switchable lenses. Each of the switchable lenses has at least two states. The switchable lens assembly has different optical powers for different states of the plurality of lenses. When the plurality of lenses are set to a specific state, the switchable lens assembly has different optical powers for different wavelengths. The system further includes an electronic device, which communicates with the switchable lens to change the state of the plurality of lenses. The electronic device is configured to cause different lenses of the plurality of switchable lenses to be in different states for different wavelengths.

[0022] In another aspect, a method of preparing an eyepiece for augmented reality glasses configured to direct light into an eye of a wearer to present an image to the wearer includes providing a substrate. The method further includes forming a first lens region on the substrate, wherein the first lens region includes a transparent liquid crystal lens having optical power. The method further includes providing a second region on the substrate, the second region being transparent and having no optical power.

[0023] On the other hand, a head-mounted display system is configured to project light into the eyes of a user to display augmented reality image content in the user's field of view. The head-mounted display system includes a frame configured to be supported on the head of the user. The display system further includes an eyepiece, which is disposed on the frame. At least a portion of the eyepiece is transparent and is disposed in a position in front of the user's eyes when the user wears the head-mounted display, so that the transparent portion transmits light from the environment in front of the user to the user's eyes to provide a view of the environment in front of the user. The eyepiece is configured to emit light into the user's eyes to display augmented reality image content to the user's field of view. The display system further includes at least one switchable lens assembly, which includes a plurality of switchable lenses, wherein each of the switchable lenses has at least two states. A change in the state of the switchable lens changes the state of the at least one switchable assembly. For different states of the plurality of lenses, the switchable lens assembly has different optical powers. When the plurality of lenses are set to a specific state, the switchable lens assembly has different optical powers for different wavelengths. The display system further includes an electronic device that communicates with the switchable lens to change the state of the plurality of lenses. The display device is configured to emit a first color light into the user's eyes at a first time and emit a second color light into the user's eyes at a second time to display augmented reality image content to the user's field of view. The electronic device is configured to cause at least one of the lenses to be in different states at the first time and the second time to provide images of the first color and the second color.

[0024] In order to summarize the present invention and the advantages achieved over the prior art, certain objects and advantages are described herein. Of course, it should be understood that not all of these objects or advantages need to be achieved according to any particular embodiment. Thus, for example, those skilled in the art will recognize that the present invention can be embodied or performed in a manner that can achieve or optimize one advantage or a group of advantages without necessarily achieving other objects or advantages.

[0025] All of these embodiments are intended to be within the scope of the invention disclosed herein. These and other embodiments will become readily apparent to those skilled in the art from the following detailed description with reference to the accompanying drawings, the invention not being limited to any particular disclosed embodiment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 An augmented reality (AR) view seen by a user through an AR device is shown.

[0027] Figure 2 A conventional display system for simulating a three-dimensional image for a user is shown.

[0028] Figures 3A to 3C The relationship between the radius of curvature and the focal radius is shown.

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

[0030] Figure 4B Examples of different accommodation and vergence states for a pair of eyes of a user are shown.

[0031] Figure 4C An example of a top view representation of a user viewing content via a display system is shown.

[0032] Figure 4D Another example of a top view representation of a user viewing content via a display system is shown.

[0033] Figure 5 Aspects of a method for simulating three-dimensional images by modifying wavefront divergence are shown.

[0034] Figure 6 An example of a waveguide stack for outputting image information to a user is shown.

[0035] Figure 7 An example of an outgoing light beam output by a waveguide is shown.

[0036] Figure 8 An example of a stacked waveguide assembly is shown where each depth plane includes an image formed using multiple different component colors.

[0037] Fig. 9A A cross-sectional side view of an example of a set of stacked waveguides each including an in-coupling optical element is shown.

[0038] Fig. 9B Shows Fig. 9A A perspective view of an example of multiple stacked waveguides.

[0039] Fig. 9CShows Fig. 9A and 9B A top plan view of an example of multiple stacked waveguides.

[0040] Fig.9D An example of a wearable display system is shown.

[0041] Fig.10 An example of a display system including a pair of adaptive lens assemblies is shown.

[0042] Fig.11A A method of displaying virtual content to a user at a virtual depth plane is shown. Fig.10 An example of a display system.

[0043] Fig. 11B A diagram showing providing a view of real world content to a user Fig.10 An example of a display system.

[0044] Fig. 12A An example of a wave plate lens assembly including liquid crystal is shown.

[0045] Fig. 12B An example of a switchable wave plate lens comprising liquid crystal is shown.

[0046] Fig.13A A cross-sectional view of an example of a switchable wave plate including a twisted nematic liquid crystal layer is shown.

[0047] Fig. 13B An example of a switchable wave plate assembly operating with activation or deactivation of a switchable wave plate is shown, the switchable wave plate assembly comprising a pair of quarter wave plates interposed between Fig.13A Switchable wave plates.

[0048] Fig. 13C An example of a quarter wave plate comprising multiple twisted nematic liquid crystal layers is shown.

[0049] Fig.13D An example of a switchable wave plate assembly is shown, which includes a pair of quarter wave plates integrated into a single stack using an adhesive layer between Fig.13A Switchable wave plates.

[0050] Fig.13E An example of a switchable wave plate assembly is shown that includes a twisted nematic liquid crystal layer between a pair of quarter wave plates integrated into a single stack.

[0051] Fig.13F An example of a switchable wave plate assembly is shown, which includes a switchable wave plate assembly integrated into a single stack. Fig. 13C A twisted nematic liquid crystal layer between a pair of quarter-wave plates.

[0052] Fig.14A A perspective view showing an example of one of a pair of transparent electrodes for switching a liquid crystal layer.

[0053] Fig. 14B A perspective view showing an example of the other of a pair of transparent electrodes for switching a liquid crystal layer.

[0054] Fig. 14C A perspective view showing an example of a pair of vertically separated transparent electrodes for switching a liquid crystal layer.

[0055] Fig.15A A plan view showing an example of a pair of horizontally staggered transparent electrodes for switching a liquid crystal layer.

[0056] Fig. 15B Shown include Fig.15A Cross-sectional view of an example of a switchable wave plate assembly of a pair of horizontally staggered transparent electrodes.

[0057] Fig.16A A plan view showing an example of a wave plate lens including liquid crystal is shown.

[0058] Fig. 16B A plan view showing an example of a wave plate lens including liquid crystal is shown.

[0059] Fig. 16C An example of a wave plate lens is shown, which provides different optical powers to diverge or converge light passing therethrough according to the polarization of the light and the incident side of the light.

[0060] Fig.16D An example of a wave plate lens is shown, which provides different optical powers to diverge or converge light passing therethrough according to the polarization of the light and the incident side of the light.

[0061] Fig.17A An example of an adaptive lens assembly including a wave plate lens and a switchable wave plate is shown.

[0062] Fig. 17B shows the operation with the switchable wave plate activated Fig.17A An example of an adaptive lens assembly.

[0063] Fig. 17C shows operation with the switchable wave plate deactivated Fig.13A An example of an adaptive lens assembly.

[0064] Fig.18A An example of a display device operating with a switchable wave plate activated is shown, the display device comprising a waveguide positioned between a pair of adaptive lens assemblies, each adaptive lens assembly comprising a wave plate lens and a switchable wave plate.

[0065] Fig.18B shows operation with the switchable wave plate deactivated Fig.18A An example of a display device.

[0066] Fig.19A A plan view of an example arrangement of liquid crystal molecules closest to a substrate of a broadband wave plate lens including liquid crystal is shown.

[0067] Fig.19B Shown include Fig.19A The arrangement shown is of a broadband wave plate lens of liquid crystal that focuses light having a first circular polarization.

[0068] Fig.19C Shown include Fig.19A The arrangement shown is of a liquid crystal broadband wave plate lens that disperses light having a second circular polarization.

[0069] Fig. 20A A plan view showing an example arrangement of liquid crystal molecules for a broadband wave plate lens including multiple twisted nematic liquid crystal layers.

[0070] Fig. 20B A cross-sectional view of an example of a broadband wave plate lens including multiple twisted nematic liquid crystal layers is shown.

[0071] Fig.21 A cross-sectional view of an example of a broadband wave plate lens including a liquid crystal layer having a birefringence that increases with increasing wavelength is shown.

[0072] Fig.22A A cross-sectional view of an example of a deactivated switchable broadband waveplate lens that diverges and flips the polarization of light having a first circular polarization is shown.

[0073] Fig. 22B A cross-sectional view of an example of a deactivated switchable broadband waveplate lens that concentrates and flips the polarization of light having a second circular polarization is shown.

[0074] Fig. 22C A cross-sectional view of an example of an activated switchable broadband waveplate lens that passes circularly polarized light without substantial convergence or divergence while maintaining its polarization is shown.

[0075] Fig.23A An example of a broadband adaptive wave plate lens assembly comprising a pair of broadband switchable wave plate lenses operating with both switchable wave plate lenses deactivated is shown.

[0076] Fig. 23B The operation of the switchable wave plate lens is shown in FIG. Fig.23A Broadband adaptive wave plate lens assembly.

[0077] Fig.23C The operation of the switchable wave plate lens is shown with one of the switchable wave plate lenses activated. Fig.23A Broadband adaptive wave plate lens assembly.

[0078] Fig.23D An example of a broadband adaptive wave plate lens assembly comprising a pair of broadband switchable wave plate lenses operating with both switchable wave plate lenses activated is shown.

[0079] Fig.24A An example of an integrated broadband adaptive wave plate lens assembly including a switchable broadband wave plate lens between a pair of active broadband switchable wave plate lenses is shown.

[0080] Fig. 24B shows the combined operation of a broadband half-wave plate lens Fig.24A Broadband adaptive wave plate lens assembly.

[0081] Fig.24C shows the operation of the switchable broadband wave plate when it is activated. Fig. 24B Broadband adaptive wave plate lens assembly.

[0082] Fig.24D shows the operation with the switchable broadband wave plate deactivated. Fig. 24B Broadband adaptive wave plate lens assembly.

[0083] Fig.25A The switchable broadband wave plate is activated. Fig.24A The simulated diffraction efficiency of a broadband adaptive waveplate lens assembly versus wavelength within the visible spectrum.

[0084] Fig.25B The switchable broadband wave plate is deactivated. Fig.24A The simulated diffraction efficiency of a broadband adaptive waveplate lens assembly versus wavelength within the visible spectrum.

[0085] Fig.26A The relationship between the simulated actual optical power and the target optical power of an example broadband adaptive waveplate lens assembly including three broadband switchable waveplate lenses is shown, where a single lens state and multiple lens states are used for blue wavelengths.

[0086] Fig.26B The relationship between the simulated actual optical power and the target optical power of an example broadband adaptive waveplate lens assembly including three broadband switchable waveplate lenses is shown, where a single lens state and multiple lens states are used for the green wavelength.

[0087] Fig.26CThe relationship between the simulated actual optical power and the target optical power of an example broadband adaptive waveplate lens assembly including three broadband switchable waveplate lenses is shown, where a single lens state and multiple lens states are used for the red wavelength.

[0088] Figures 27A to 27C An example method of making a broadband wave plate or a broadband wave plate lens is shown.

[0089] Fig.28 An example method of configuring an alignment layer using dual beam exposure to align liquid crystal molecules in a broadband wave plate or a broadband wave plate lens is shown.

[0090] Figures 29A to 29B An example method of configuring an alignment layer using a main lens to align liquid crystal molecules in a broadband wave plate or a broadband wave plate lens is shown.

[0091] Figures 30A to 30B An example method of configuring a nanoimprint alignment layer using a master lens and single beam exposure to align liquid crystal molecules in a broadband wave plate or broadband wave plate lens is shown.

[0092] Fig. 30C Shows the use of Figures 30A to 30B An example method to align an example nanoimprint alignment layer of liquid crystal molecules for a broadband wave plate lens.

[0093] Figures 31A to 31C An example method of fabricating a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal using a gap-filling process is shown.

[0094] Figures 32A to 32E An example method of fabricating a switchable broadband wave plate comprising liquid crystal or a switchable broadband wave plate lens comprising liquid crystal using a layer transfer process is shown.

[0095] Fig.33 An example of a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal formed on a portion of a substrate is shown.

[0096] Fig.34 An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by selective coating is shown.

[0097] Figures 35A to 35C An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by blanket coating a liquid crystal layer and subtractively removing the liquid crystal layer is shown.

[0098] Figures 36A to 36CAn example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by using selective optical patterning of an alignment layer is shown.

[0099] Figures 37A to 37B An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by using selective nanoimprinting of an alignment layer is shown.

[0100] Reference numerals may be repeated throughout the drawings to indicate corresponding relationships between referenced elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the present disclosure. DETAILED DESCRIPTION

[0101] AR systems can display virtual content to a user or viewer while still allowing the user to see the world around them. Preferably, the content is displayed on a head-mounted display, such as part of glasses, which projects image information into the user's eyes. In addition, the display can also transmit light from the surrounding environment to the user's eyes to allow viewing 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 worn on the head of a viewer or user.

[0102] In some AR systems, multiple waveguides may be configured to form virtual images at multiple virtual depth planes (also referred to herein simply as "depth planes"). Different ones of the multiple waveguides may have different optical powers and may be formed at different distances relative to the user's eyes. The display system may also include multiple lenses that provide or otherwise provide optical powers. The optical powers of the waveguides and / or lenses may provide images at different virtual depth planes. Disadvantageously, each of the waveguides and lenses increases the overall thickness, weight, and cost of the display.

[0103] Advantageously, in various embodiments described herein, an adaptive lens assembly can be utilized to provide variable optical power, for example to modify the wavefront divergence of light propagating through the lens assembly, thereby providing a virtual depth plane at different perceived distances relative to the user. The adaptive lens assembly can include a pair of wave plate lenses with a switchable wave plate disposed between the pair of wave plate lenses. Each of the first and second wave plate lenses can be configured to change the polarization state of light passing therethrough, and the switchable wave plate can be switchable between a plurality of states, for example, between a first state that allows light to pass without changing the polarization of the light and a second state that changes the polarization of the light (e.g., by changing the handedness of the polarization). In some embodiments, one or both of the wave plate lenses can be switched between the first state and the second state, and the intermediate switchable wave plate described above can be omitted.

[0104] It should be understood that the adaptive lens assembly may include a stack of multiple wave plate lenses and multiple switchable wave plates. For example, the adaptive lens assembly may include multiple sub-assemblies including a pair of wave plate lenses with an intermediate switchable wave plate. In some embodiments, the adaptive lens assembly may include alternating wave plate lenses and switchable wave plates. Advantageously, this alternating arrangement allows for reduced thickness and weight by allowing adjacent switchable wave plates to share a common wave plate lens. In some embodiments, more than two discrete optical power levels may be provided by switching the states of various combinations of switchable wave plates in the stack.

[0105] In some embodiments, an adaptive lens assembly forms a display device having a waveguide assembly to form images at different virtual depth planes. In various embodiments, the display device includes a pair of adaptive lens assemblies with a waveguide assembly inserted therein. The waveguide assembly includes a waveguide configured to propagate (e.g., via total internal reflection) light (e.g., visible light) therein and couple out the light. For example, the light can be coupled out along an optical axis direction perpendicular to the main surface of the waveguide. One of the pair of adaptive lens assemblies can be formed on a first side of the waveguide assembly and can be configured to provide a variable optical focal length to modify the wavefront of the light passing through the adaptive lens assembly, thereby forming an image at each of the multiple virtual depth planes. For example, the adaptive lens assembly can converge or diverge the coupled out light received from the waveguide assembly. In order to compensate for the modification of the real world view caused by the convergence or divergence of ambient light propagating through the adaptive lens assembly and / or the waveguide assembly, the other of the pair of adaptive lens assemblies is additionally disposed on a second side of the waveguide assembly opposite to the first side. When the switchable wave plate of each adaptive lens assembly assumes a corresponding state, the adaptive lens assembly can have optical focal lengths of opposite signs so that the other of the adaptive lens assemblies corrects the distortion caused by the adaptive lens assembly on the first side of the waveguide assembly.

[0106] Advantageously, utilizing a switchable waveplate that can be switched between two states simplifies actuation of the adaptive lens assembly relative to a continuously variable adaptive lens having a continuously variable optical element, and reduces the computational power required to determine how to appropriately activate the adaptive lens assembly to obtain a desired optical power. Additionally, by allowing the adaptive lens assembly to modify the wavefront divergence of light output by the waveguides, the number of waveguides required to provide multiple depth planes is reduced relative to an arrangement in which each waveguide provides a specific amount of wavefront divergence.

[0107] Reference will now be made to the drawings, in which like reference numerals represent like parts throughout the drawings. Unless otherwise indicated, the drawings are schematic and are not necessarily drawn to scale.

[0108] Example Display System

[0109] Figure 2 A conventional display system for simulating a three-dimensional image for a user is shown. It will be appreciated that the user's eyes are spaced apart, and when viewing a real object in space, each eye has a slightly different view of the object, and an image of the object may be formed at a different location on the retina of each eye. This may be referred to as binocular parallax, and may be used by the human visual system to provide a sense of depth. Conventional display systems simulate binocular parallax by presenting two different images 190, 200 (one for each eye 210, 220) with slightly different views of the same virtual object, corresponding to views of the virtual object that would be seen by each eye as a real object at the desired depth. These images provide binocular cues that the user's visual system may interpret to obtain a sense of depth.

[0110] Continue to refer Figure 2 , the images 190, 200 are spaced a distance 230 from the eyes 210, 220 on the z-axis. The z-axis is parallel to the optical axis of the viewer whose eyes are looking at an object at optical infinity directly in front of the viewer. The images 190, 200 are flat and are kept at a fixed distance from the eyes 210, 220. Based on the slightly different views of the virtual objects in the images presented to the eyes 210, 220, respectively, the eyes can naturally rotate so that the image of the object falls on the corresponding point on the retina of each eye to maintain a single binocular vision. The rotation can cause the line of sight of each eye 210, 220 to converge to the point in space where the virtual object is perceived to exist. Therefore, providing a three-dimensional image generally involves providing binocular cues that can manipulate the vergence of the user's eyes 210, 220 and are interpreted by the human visual system to provide a sense of depth.

[0111] However, producing a realistic and comfortable sense of depth is challenging. It should be understood that light from objects at different distances from the eye has wavefronts with different amounts of divergence. Figures 3A to 3C The relationship between distance and light divergence is shown. The distance between the object and the eye 210 is represented in the order of decreasing distance R1, R2 and R3. Figures 3A to 3C As shown, as the distance to the object decreases, the light becomes more divergent. Conversely, as the distance increases, the light becomes more collimated. In other words, it can be said that the light field generated by a point (object or part of an object) has a spherical wavefront curvature that is a function of how far the point is from the user's eye. The curvature increases as the distance between the object and the eye 210 decreases. Although for clarity in the description of Figures 3A to 3C Only a single eye 210 is shown in and other figures herein, but the discussion regarding eye 210 is applicable to both eyes 210 and 220 of a viewer.

[0112] Continue to refer Figures 3A to 3C, light from an object being looked at by a viewer's eye can have different degrees of wavefront divergence. Due to different amounts of wavefront divergence, light can be focused differently by the lens of the eye, which in turn may require the lens to assume different shapes to form a focused image on the retina of the eye. In the absence of a focused image formed on the retina, the resulting retinal blur acts as an accommodation cue, which causes a change in the shape of the eye lens until a focused image is formed on the retina. For example, an accommodation cue can trigger the ciliary muscles surrounding the eye lens to relax or contract, thereby adjusting the force applied to the suspensory ligaments that hold the lens, thereby changing the shape of the eye lens until the retinal blur of the looked object is eliminated or minimized, thereby forming a focused image of the looked object on the retina of the eye (e.g., the fovea). 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 the looked object on the retina of the eye (e.g., the fovea) may be referred to as an accommodation state.

[0113] Reference now Figure 4A , shows a representation of the accommodation-vergence response of the human visual system. Movement of the eyes to fixate on an object causes the eyes to receive light from the object, where the light forms an image on each retina of the eye. The presence of retinal blur in the image formed on the retina can provide accommodation cues, and the relative positions of the images on the retina can provide vergence cues. Accommodation cues cause accommodation to occur, so that the eye lenses each assume a specific accommodation state that forms a focused image of the object on the retina of the eye (e.g., the fovea). On the other hand, vergence cues cause vergence movements (eye rotations) to occur, so that the images formed on each retina of each eye are at corresponding retinal points that maintain single binocular vision. In these positions, it can be said that the eyes have assumed a specific vergence state. Continue with reference to Figure 4A , accommodation can be understood as the process by which the eye achieves a specific accommodation state, and vergence can be understood as the process by which the eye achieves a specific vergence state. Figure 4A As shown, if the user looks at another object, the accommodation and vergence states of the eyes may change. For example, if the user looks at a new object at a different depth on the z-axis, the accommodation state may change.

[0114] Without being limited by theory, it is believed that a viewer of an object may perceive the object as "three-dimensional" due to a combination of vergence and accommodation. As described above, the vergence movement of the two eyes relative to each other (e.g., the rotation of the eyes so that the pupils move toward or away from each other so that the eyes' line of sight converges to focus on an object) is closely related to the accommodation of the eye lenses. Under normal circumstances, changing the shape of the eye lenses to change the focus from one object to another at a different distance will automatically result in a matching change in vergence to the same distance, according to a relationship known as the "accommodation-vergence reflex." Likewise, under normal circumstances, a change in vergence will trigger a matching change in lens shape.

[0115] Reference now Figure 4B , examples of different accommodation states and vergence states of eyes are shown. A pair of eyes 222a is looking at an object at optical infinity, while a pair of eyes 222b is looking at an object 221 that is less than optical infinity. It is worth noting that the vergence state of each pair of eyes is different, with one pair of eyes 222a looking straight ahead and one pair of eyes 222 converging on object 221. The accommodation state of the eyes forming each pair of eyes 222a and 222b is also different, as shown by the different shapes of the lenses 210a, 220a.

[0116] Unexpectedly, many users of conventional "3D" display systems find that such conventional systems are uncomfortable or may not perceive a sense of depth at all due to the mismatch between the accommodation and vergence states in these displays. As described above, many stereoscopic or "3D" 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, such systems only provide different presentations of the scene and cause changes in the vergence state of the eyes, but there is no corresponding change in the accommodation state of these eyes. Instead, the image is shown by a display at a fixed distance relative to the eyes, so that the eyes view all image information in a single accommodation state. This arrangement responds to the "accommodation-vergence reflex" by causing a change in the vergence state without a matching change in the accommodation state. This mismatch is believed to cause discomfort to the viewer. A display system that provides a better match between accommodation and vergence can form a more realistic and comfortable three-dimensional image simulation.

[0117] Without being limited by theory, it is believed that the human eye can generally interpret a limited number of depth planes to provide a sense of depth. Therefore, a highly credible simulation of perceived depth can be achieved by providing the eye with a different image presentation corresponding to each of these limited number of depth planes. In some embodiments, the different presentations can provide both vergence cues and matching accommodation cues, thereby providing a physiologically correct accommodation-vergence match.

[0118] Continue to refer Figure 4B, two depth planes 240 are shown, corresponding to different spatial distances relative to the eyes 210, 220. For a given depth plane 240, vergence cues may be provided by displaying an image with an appropriately different perspective for each eye 210, 220. In addition, 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 produced by a point at the distance of that depth plane 240.

[0119] In the illustrated embodiment, the distance along the z-axis of the depth plane 240 containing point 221 is 1 meter. As used herein, the distance or depth along the z-axis can be measured using a zero point located at the user's eye exit pupil. Therefore, the depth plane 240 located at a depth of 1 meter corresponds to a distance of 1 meter from the user's eye exit pupil on the optical axis of the user's eye, where the eye points to optical infinity. As an approximation, the depth or distance along the z-axis can be measured from the display in front of the user's eye (e.g., from the surface of the waveguide), plus the value of the distance between the device and the user's eye exit pupil. This value can be referred to as the exit pupil distance and corresponds to the distance between the user's eye exit pupil and the display that the user wears in front of the eye. In practice, the value of the exit pupil distance can be a standardized value that is common to all viewers. For example, it can be assumed that the exit pupil distance is 20mm, and the depth plane at a depth of 1 meter can be at a distance of 980mm in front of the display.

[0120] Reference now Figure 4C and 4D , respectively show examples of matched accommodation-vergence distance and mismatched accommodation-vergence distance. Figure 4C As shown, the display system can provide an image of a virtual object to each eye 210, 220. These images can cause the eyes 210, 220 to present a state of convergence, in which the eyes converge at a point 15 on the depth plane 240. In addition, the image can be formed by light having a wavefront curvature corresponding to a real object at the depth plane 240. As a result, the eyes 210, 220 present an accommodation state, in which the image is focused on the retinas of these eyes. Therefore, the user can perceive the virtual object as being located at a point 15 on the depth plane 240.

[0121] It should be understood that each of the accommodation and vergence states of the eyes 210, 220 is associated with a specific distance on the z-axis. For example, an object at a specific distance from the eyes 210, 220 causes the eyes to assume a specific accommodation state based on the distance of the object. The distance associated with a specific accommodation state may be referred to as the accommodation distance A. d Similarly, there is a specific vergence distance V associated with a specific vergence state. dor positions relative to each other. In the case where the accommodation distance and the vergence distance match, the relationship between accommodation and vergence can be said to be physiologically correct. This is considered to be the most comfortable scenario for the viewer.

[0122] However, in stereoscopic displays, the accommodation distance and the vergence distance may not always match. Figure 4D As shown, the image displayed to the eyes 210, 220 can be displayed with a wavefront divergence corresponding to the depth plane 240, and the eyes 210, 220 can present a specific accommodation state in which the points 15a, 15b on the depth plane are in focus. However, the image displayed to the eyes 210, 220 can provide a vergence cue that causes the eyes 210, 220 to converge at a point 15 that is not located on the depth plane 240. Therefore, in some embodiments, the accommodation distance corresponds to the distance from the exit pupil of the eyes 210, 220 to the depth plane 240, while the vergence distance corresponds to the greater distance from the exit pupil of the eyes 210, 220 to the point 15. The accommodation distance is different from the vergence distance. Therefore, there is an accommodation-vergence mismatch. This mismatch is considered undesirable and may cause discomfort to the user. It should be understood that the mismatch corresponds to the distance (e.g., V d -A d ) and can be characterized using diopters.

[0123] In some embodiments, it should be understood that a reference point other than the exit pupil of the eye 210, 220 may be used to determine the distance used to determine the accommodation-vergence mismatch, as long as the same reference point is used for the accommodation distance and the vergence distance. For example, the distance from the cornea to the depth plane, from the retina to the depth plane, from the eyepiece (e.g., a waveguide of a display device) to the depth plane, etc. may be measured.

[0124] Without being limited by theory, it is believed that the user may still perceive accommodation-vergence mismatches of up to 0.25 diopters, up to 0.33 diopters, and up to about 0.5 diopters as physiologically correct without causing noticeable discomfort by itself. In some embodiments, the display systems disclosed herein (e.g., Figure 6 The display system 250 in the embodiment of the present invention presents an image with an accommodation-vergence mismatch of about 0.5 diopters or less to a viewer. In some other embodiments, the accommodation-vergence mismatch of the image provided by the display system is about 0.33 diopters or less. In some other embodiments, the accommodation-vergence mismatch of the image provided by the display system is about 0.25 diopters or less, including about 0.1 diopters or less.

[0125] Figure 5Aspects of a method for simulating a three-dimensional image by modifying wavefront divergence are shown. The display system includes a waveguide 270 configured to receive light 770 encoded with image information and output the light to the user's eye 210. The waveguide 270 can output light 650 with a defined amount of wavefront divergence that corresponds to the wavefront divergence of the light field produced 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 the depth plane. In addition, it will be described that image information from a similar waveguide can be provided to the user's other eye.

[0126] In some embodiments, a single waveguide may be configured to output light having a set amount of wavefront divergence corresponding to the wavefront divergence of a single depth plane or a finite number of depth planes, and / or the waveguide may be configured to output light of a finite range of wavelengths. Thus, in some embodiments, multiple waveguides or waveguide stacks may be utilized to provide different amounts of wavefront divergence for different depth planes and / or output light of different wavelength ranges. As used herein, it should be understood that a depth plane may be planar or may have a curved profile.

[0127] Figure 6 An example of a waveguide stack for outputting image information to a user is shown. The display system 250 includes a waveguide stack or stacked waveguide assembly 260, which can be used to provide a three-dimensional perception to the eye / brain using multiple waveguides 270, 280, 290, 300, 310. It should be understood that in some embodiments, the display system 250 can be considered a light field display. In addition, the waveguide assembly 260 can also be referred to as an eyepiece.

[0128] In some embodiments, the display system 250 may be configured to provide a substantially continuous vergence cue and a plurality of discrete accommodation cues. The vergence cue may be provided by displaying a different image to each eye of the user, and the accommodation cue may be provided by outputting light for forming an image with a selectable discrete amount of wavefront divergence. In other words, the display system 250 may be configured to output light with variable wavefront divergence levels. 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.

[0129] Continue to refer Figure 6, the waveguide assembly 260 may also include a plurality 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 plurality of lenses 320, 330, 340, 350 may be configured to send image information to the eye at various levels of wavefront curvature or light divergence. Each waveguide level may be associated with a particular depth plane and may be configured to output image information corresponding to the depth plane. The image injection device 360, 370, 380, 390, 400 may be used as a light source for the waveguide and may be used to inject image information into the waveguides 270, 280, 290, 300, 310, as described herein, each waveguide may be configured to distribute incident light across each corresponding waveguide to be output toward the eye 210. Light exits the output surfaces 410, 420, 430, 440, 450 of the image injection devices 360, 370, 380, 390, 400 and is injected into the 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 part of a 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 (e.g., a collimated beam) may be injected into each waveguide to output an entire field of cloned collimated beams directed toward the eye 210 at a specific angle (and divergence) corresponding to a depth plane associated with the particular waveguide. In some embodiments, a single one of the image injection devices 360, 370, 380, 390, 400 may be associated with multiple (eg, three) of the waveguides 270, 280, 290, 300, 310 and inject light therein.

[0130] In some embodiments, the image injection devices 360, 370, 380, 390, 400 are discrete displays that each generate image information for injection into a corresponding waveguide 270, 280, 290, 300, 310. In some other embodiments, the image injection devices 360, 370, 380, 390, 400 are outputs of a single multiplexed display, which may, for example, pipe the image information to each of the image injection devices 360, 370, 380, 390, 400 via one or more optical conduits (e.g., fiber optic cables). It should be understood that the image information provided by the image injection devices 360, 370, 380, 390, 400 may include light of different wavelengths or colors (e.g., different component colors as discussed herein).

[0131] 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 can be directed and modified by a light modulator 540 (e.g., a spatial light modulator) via a beam splitter 550. The light modulator 540 can be configured to change the perceived intensity of the light injected into the waveguides 270, 280, 290, 300, 310 to 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 the image injection devices 360, 370, 380, 390, 400 are shown schematically, and in some embodiments, these image injection devices can represent different optical paths and positions in a common projection system that is configured to output light into associated waveguides in waveguides 270, 280, 290, 300, 310. In some embodiments, the waveguides in the waveguide assembly 260 can act as ideal lenses while relaying the light injected into the waveguides to the user's eyes. In this concept, the object can be the spatial light modulator 540, and the image can be an image on a depth plane.

[0132] In some embodiments, the display system 250 may be a scanning fiber display including one or more scanning fibers configured to project light into one or more waveguides 270, 280, 290, 300, 310 in various patterns (e.g., raster scan, spiral scan, Lissajous pattern, etc.), and ultimately to the viewer's eye 210. In some embodiments, the image injection devices 360, 370, 380, 390, 400 shown may schematically represent a single scanning fiber or a scanning fiber bundle configured to inject light into one or more waveguides 270, 280, 290, 300, 310. In some other embodiments, the image injection devices 360, 370, 380, 390, 400 shown may schematically represent a plurality of scanning optical fibers or a plurality of scanning optical fiber bundles, each of which is configured to inject light into an associated waveguide 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 the one or more waveguides 270, 280, 290, 300, 310. It should be understood that one or more intermediate optical structures may be provided between the one or more scanning optical fibers and the one or more waveguides 270, 280, 290, 300, 310 to, for example, redirect light emitted from the scanning optical fibers into the one or more waveguides 270, 280, 290, 300, 310.

[0133] The controller 560 controls the operation of one or more of the stacked waveguide assemblies 260, including the operation of the image injection 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-transitory medium) that adjusts the timing and provides image information to the waveguides 270, 280, 290, 300, 310 according to any of the various schemes disclosed herein, for example. In some embodiments, the controller can be a single integral device, or a distributed system connected by wired or wireless communication channels. In some embodiments, the controller 560 can be a processing module 140 or 150 ( Fig.9D ) part.

[0134] Continue to refer Figure 6, the waveguides 270, 280, 290, 300, 310 can be configured to propagate light within each respective waveguide by total internal reflection (TIR). The waveguides 270, 280, 290, 300, 310 can each be planar or have another shape (e.g., curved), having a top major surface and a bottom major surface and an edge extending between these top major surfaces and bottom major surfaces. In the configuration shown, the waveguides 270, 280, 290, 300, 310 can each include an outcoupling optical element 570, 580, 590, 600, 610, which is configured to extract light from the waveguide by redirecting the light, propagating within the respective corresponding waveguide, and emitting from the waveguide to output image information to the eye 210. The extracted light can also be referred to as outcoupled light, and the outcoupling optical element light can also be referred to as a light extraction optical element. The extracted light beam can be output by the waveguide at the location where the light propagating in the waveguide impinges on the light extraction optical element. As further discussed herein, the outcoupling optical element 570, 580, 590, 600, 610 can be, for example, a grating, which includes a diffractive optical feature. Although shown as being disposed at the bottom major surface of the waveguide 270, 280, 290, 300, 310, for ease of description and clarity of drawing, in some embodiments, as further discussed herein, the outcoupling optical element 570, 580, 590, 600, 610 can be disposed at the top and / or bottom major surface, and / or can be disposed directly within the volume of the waveguide 270, 280, 290, 300, 310. In some embodiments, the outcoupling optical element 570, 580, 590, 600, 610 can be formed in a material layer attached to a transparent substrate to form the waveguide 270, 280, 290, 300, 310. In some other embodiments, the waveguides 270, 280, 290, 300, 310 may be a single piece of material and the outcoupling optical elements 570, 580, 590, 600, 610 may be formed on a surface and / or within the interior of the piece of material.

[0135] Continue to refer Figure 6As discussed herein, each waveguide 270, 280, 290, 300, 310 is configured to output light to form an image corresponding to a particular depth plane. For example, the waveguide 270 closest to the eye can be configured to deliver collimated light (which is injected into such waveguide 270) to the eye 210. This collimated light can represent an optical infinity focal plane. The next upstream waveguide 280 can be configured to emit collimated light that is transmitted through a first lens 350 (e.g., a negative lens) before it can reach the eye 210; such a first lens 350 can be configured to produce a slightly convex wavefront curvature so that the eye / brain interprets light from the next upstream waveguide 280 as coming from a first focal plane that is closer to the eye 210 from optical infinity inward. Similarly, the third upstream waveguide 290 transmits its output light through both the first lens 350 and the second lens 340 before reaching the eye 210; the combined optical power of the first lens 350 and the second lens 340 can be configured to produce another increment of wavefront curvature so that the eye / brain interprets light from the third waveguide 290 as coming from a second focal plane that is further inward from optical infinity and closer to the person than light from the next upstream waveguide 280.

[0136] 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 lenses between it and the eye to obtain a total focal power that represents the focal plane closest to the person. In order to compensate for the lens stack 320, 330, 340, 350 when observing / interpreting light from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 can be provided at the top of the stack to compensate for the total focal power of the lens stack 320, 330, 340, 350 below. This configuration provides as many perceived focal planes as there are available waveguide / lens pairs. Both the outcoupling optics of the waveguide and the focusing aspects of the lens can be static (i.e., not dynamic or electro-active). In some alternative embodiments, one or both of them can be dynamic by using electro-active features.

[0137] 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 sets of images to the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output sets of images to the same multiple depth planes, one set per depth plane. This may provide advantages for forming tiled images to provide an extended field of view at those depth planes.

[0138] Continue to refer Figure 6, the out-coupling optical elements 570, 580, 590, 600, 610 can be configured to both redirect light out of their respective waveguides 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 can have differently configured out-coupling optical elements 570, 580, 590, 600, 610, and the differently configured out-coupling optical elements 570, 580, 590, 600, 610 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 can be volume features or surface features that can be configured to output light at a particular angle. For example, the light extraction optical elements 570, 580, 590, 600, 610 can be volume holograms, surface holograms, and / or diffraction gratings. In some embodiments, features 320, 330, 340, 350 may not be lenses; instead, they may simply be spacers (eg, cladding and / or structures used to form air gaps).

[0139] In some embodiments, the outcoupling optical elements 570, 580, 590, 600, 610 are diffractive features that form a diffraction pattern, or "diffractive optical elements" (also referred to herein as "DOEs"). Preferably, the DOE has a sufficiently low diffraction efficiency that only a portion of the beam is deflected toward the eye 210 by each intersection of the DOE, while the remainder continues through the waveguide via TIR. Thus, the light carrying the image information is split into multiple related exit beams that exit the waveguide at multiple locations, and for this particular collimated beam bouncing within the waveguide, the result is a fairly uniform pattern exiting toward the eye 210.

[0140] 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 include a polymer dispersed liquid crystal layer in which a droplet includes a diffraction pattern in a host medium, and the refractive index of the droplet may be switched to substantially match that of the host material (in which case the pattern does not significantly diffract incident light) or the droplet may be switched to a refractive index that mismatches that of the host medium (in which case the pattern actively diffracts incident light).

[0141] In some embodiments, a camera assembly 630 (e.g., a digital camera, including a visible light camera and an infrared light camera) 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 state 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 to project light (e.g., infrared light) to 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 attached to the frame 80 ( Fig.9D ) and can be in electrical communication with processing module 140 and / or processing module 150, which can process image information from camera assembly 630. In some embodiments, one camera assembly 630 can be used for each eye to monitor each eye separately.

[0142] Reference now Figure 7 , shows an example of an outgoing beam output by a waveguide. One waveguide is shown, but it should be understood that the waveguide assembly 260 ( Figure 6 ) can function similarly, wherein the waveguide assembly 260 includes multiple waveguides. Light 640 is injected 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 emerges from the waveguide as an exit beam 650. The exit beams 650 are shown as being substantially parallel, but as discussed herein, they can also be redirected to propagate to the eye 210 at an angle (e.g., to form diverging exit beams) that depends on the depth plane associated with the waveguide 270. It should be understood that substantially parallel exit beams can be indicative of a waveguide having an out-coupling optical element that couples out light to form an image that appears to be disposed at a depth plane that is a long distance away from the eye 210 (e.g., optical infinity). Other waveguides or other sets of outcoupling optical elements may output a more divergent exit beam pattern, which would require the eye 210 to adapt to a closer distance so that the more divergent exit beam pattern can be focused on the retina and will be interpreted by the brain as light coming from a distance closer to the eye 210 than optical infinity.

[0143] In some embodiments, a full color image can be formed at each depth plane by superimposing images in each of the component colors (eg, three or more component colors). Figure 8An example of a stacked waveguide assembly is shown, wherein each depth plane includes an image formed using a plurality of different component 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 component color images associated therewith, 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. Different depth planes are represented in the figure by different numbers for the diopters (dpt) following the letters G, R, and B. By way of example only, the numbers following each of these letters represent the diopters (1 / m), or the inverse of the distance of the depth plane from the viewer, and each box in the figure represents a separate component color image. In some embodiments, the precise placement of the depth planes of different component colors may vary in order to account for differences in the eye's focus on light of different wavelengths. For example, different component color images of a given depth plane may be placed on depth planes corresponding to different distances from the user. Such an arrangement may increase visual acuity and user comfort, and / or may reduce chromatic aberration.

[0144] In some embodiments, light of each component color may be output by a single dedicated waveguide, and therefore, each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figure including the letters G, R, or B may be understood to represent a separate waveguide, and each depth plane may provide three waveguides, wherein each depth plane provides three component color images. Although for ease of description, the waveguides associated with each depth plane in this figure are shown as being adjacent to each other, it should be understood that in a physical device, the waveguides may all be arranged in a stacked form with one waveguide per layer. In some other embodiments, multiple component colors may be output by the same waveguide, such that, for example, each depth plane may provide only a single waveguide.

[0145] Continue to refer Figure 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 red, green, or blue, or these other colors may replace one or more of red, green, or blue.

[0146] It should be understood that references throughout this disclosure to light of a given color will be understood to include light of one or more wavelengths within a range of wavelengths perceived by a viewer as light of the given color. For example, red light may include light of one or more wavelengths within a range of about 620-780 nm, green light may include light of one or more wavelengths within a range of about 492-577 nm, and blue light may include light of one or more wavelengths within a range of about 435-493 nm.

[0147] In some embodiments, the light source 530 ( Figure 6 ) can be configured to emit one or more wavelengths of light outside the visual perception range of a viewer, such as infrared and / or ultraviolet wavelengths of light. In addition, the incoupling, outcoupling, and other light redirecting structures of the waveguide of the display 250 can be configured to guide this light and direct it out of the display toward the user's eye 210, for example, for imaging and / or user stimulation applications.

[0148] Reference now Fig. 9A In some embodiments, it may be desirable to redirect light impinging on a waveguide to couple the light into the waveguide. Incoupling optical elements may be used to redirect and couple light into its corresponding waveguide. Fig. 9A A cross-sectional side view of an example of a plurality of stacked waveguides or stacked waveguide groups 660 is shown, each stacked waveguide including an incoupling optical element. The waveguides can each be configured to output light of one or more different wavelengths, or light of one or more different wavelength ranges. It should be understood that stack 660 can correspond to stack 260 ( Figure 6 ), and the waveguides shown in stack 660 may correspond to portions of multiple waveguides 270, 280, 290, 300, 310, in addition to light from one or more image injection devices 360, 370, 380, 390, 400 being injected into the waveguide from a location where the light needs to be redirected for coupling.

[0149] The illustrated stacked waveguide group 660 includes waveguides 670, 680, and 690. Each waveguide includes an associated coupling optical element (which may also be referred to as a light input region on the waveguide), wherein, for example, coupling optical element 700 is disposed on a major surface (e.g., top major surface) of waveguide 670, coupling optical element 710 is disposed on a major surface (e.g., top major surface) of waveguide 680, and coupling optical element 720 is disposed on a major surface (e.g., top major surface) of waveguide 690. In some embodiments, one or more of the coupling optical elements 700, 710, 720 may be disposed on the bottom major surface of the corresponding waveguide 670, 680, 690 (particularly in the case where one or more coupling optical elements are reflective deflecting optical elements). As shown, coupling optical elements 700, 710, 720 may be disposed on the top major surface of their corresponding waveguides 670, 680, 690 (or the top of the next downstream waveguide), particularly in the case where those coupling optical elements are transmissive deflecting optical elements. In some embodiments, the coupling-in optical elements 700, 710, 720 can be disposed in the body of the respective waveguides 670, 680, 690. In some embodiments, as discussed herein, the coupling-in optical elements 700, 710, 720 are wavelength selective such that they selectively redirect light of one or more wavelengths while transmitting light of other wavelengths. Although shown on one side or corner of their respective waveguides 670, 680, 690, it should be understood that in some embodiments, the coupling-in optical elements 700, 710, 720 can be disposed in other areas of their respective waveguides 670, 680, 690.

[0150] As shown, the coupling optical elements 700, 710, 720 can be laterally offset from each other. In some embodiments, each coupling optical element can be offset so that the coupling optical element receives light without transmitting through another coupling optical element. Figure 6 As shown, each coupling-in optical element 700, 710, 720 can be configured to receive light from different image injection devices 360, 370, 380, 390 and 400, and can be separated from other coupling-in optical elements 700, 710, 720 (e.g., laterally spaced apart) so that the coupling-in optical element does not substantially receive light from other coupling-in optical elements in the coupling-in optical elements 700, 710, 720.

[0151] Each waveguide further includes an associated light distribution element, wherein, for example, the light distribution element 730 is disposed on a major surface (e.g., top major surface) of the waveguide 670, the light distribution element 740 is disposed on a major surface (e.g., top major surface) of the waveguide 680, and the light distribution element 750 is disposed on a major surface (e.g., top major surface) of the waveguide 690. In some other embodiments, the light distribution elements 730, 740, 750 may be disposed on the bottom major surface of the associated waveguides 670, 680, 690, respectively. In some other embodiments, the light distribution elements 730, 740, 750 may be disposed on the top major surface and the bottom major surface of the associated waveguides 670, 680, 690, respectively; or the light distribution elements 730, 740, 750 may be disposed on different major surfaces of the top major surface and the bottom major surface in different associated waveguides 670, 680, 690, respectively.

[0152] The waveguides 670, 680, 690 may be spaced apart and separated by layers of, for example, gas, liquid, and / or solid material. For example, as shown, layer 760a may separate waveguide 670 from waveguide 680; and layer 760b may separate waveguide 680 from waveguide 690. In some embodiments, layers 760a and 760b are formed of a low refractive index material (i.e., a material having a lower refractive index than the material forming one of the immediately adjacent waveguides 670, 680, 690). Preferably, the refractive index of the material forming layers 760a, 760b differs from the refractive index of the material forming waveguides 670, 680, 690 by 0.05 or more, or 0.10 or less. Advantageously, the lower refractive index layers 760a, 760b can act as cladding that promotes total internal reflection (TIR) ​​of light passing 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 of air. Although not shown, it should be understood that the top and bottom of the illustrated waveguide set 660 may include adjacent cladding.

[0153] Preferably, for ease of manufacturing and other considerations, the materials forming waveguides 670, 680, 690 are similar or the same, and the materials forming layers 760a, 760b are similar or the same. In some embodiments, the materials forming waveguides 670, 680, 690 can be different between one or more waveguides, and / or the materials forming layers 760a, 760b can be different, while still maintaining the various refractive index relationships described above.

[0154] Continue to refer Fig. 9A, light rays 770, 780, 790 are incident on the waveguide group 660. It should be understood that light rays 770, 780, 790 may be injected through one or more image injection devices 360, 370, 380, 390, 400 ( Figure 6 ) are injected into waveguides 670, 680, and 690.

[0155] In some embodiments, the light rays 770, 780, 790 have different characteristics, e.g., different wavelengths corresponding to different colors or different wavelength ranges. The incoupling optical elements 700, 710, 720 each deflect incident light so that the light propagates through a corresponding one of the waveguides 670, 680, 690 by TIR. In some embodiments, the incoupling optical elements 700, 710, 720 each selectively deflect one or more specific wavelengths of light while transmitting other wavelengths to the underlying waveguide and associated incoupling optical element.

[0156] For example, the coupling-in optical element 700 can be configured to deflect light 770 having a first wavelength or a first wavelength range, while transmitting light 780 having a different second wavelength or a second wavelength range and light 790 having a third wavelength or a third wavelength range, respectively. The transmitted light 780 impinges on and is deflected by the coupling-in optical element 710, which is configured to deflect light of the second wavelength or the second wavelength range. The light 790 is deflected by the coupling-in optical element 720, which is configured to selectively deflect light of the third wavelength or the third wavelength range.

[0157] Continue to refer Fig. 9A , the deflected light rays 770, 780, 790 are deflected so that the light rays 770, 780, 790 propagate through the corresponding waveguides 670, 680, 690; that is, the coupling-in optical element 700, 710, 720 of each waveguide deflects the light into the corresponding waveguide 670, 680, 690 to couple 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 corresponding waveguides 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the corresponding waveguides 670, 680, 690 by TIR until impinging on the corresponding light distribution elements 730, 740, 750 of the waveguides.

[0158] Reference now Fig. 9B , showing Fig. 9A670, 680, 690. As described above, the coupled-in light rays 770, 780, 790 are deflected by the coupling-in optical elements 700, 710, 720, respectively, and then propagate through TIR in the waveguides 670, 680, 690, respectively. Then, the light rays 770, 780, 790 are respectively irradiated on the light distribution elements 730, 740, 750. The light distribution elements 730, 740, 750 deflect the light rays 770, 780, 790 so that the light rays 770, 780, 790 propagate toward the coupling-out optical elements 800, 810, 820, respectively.

[0159] In some embodiments, the light distribution elements 730, 740, 750 are orthogonal pupil expanders (OPEs). In some embodiments, the OPEs deflect or distribute light to the outcoupling optical elements 800, 810, 820, and in some embodiments, may also increase the beam or spot size of the light as it propagates toward the outcoupling optical elements. In some embodiments, the light distribution elements 730, 740, 750 may be omitted, and the incoupling optical elements 700, 710, 720 may be configured to deflect light directly to the outcoupling optical elements 800, 810, 820. For example. Reference Fig. 9A , the light distribution elements 730, 740, 750 can be replaced by outcoupling optical elements 800, 810, 820, respectively. In some embodiments, the outcoupling optical elements 800, 810, 820 are exit pupils (EP) or exit pupil expanders (EPE), which direct light into the viewer's eye 210 ( Figure 7 ). It should be understood that the OPE can be configured to increase the size of the eye box in at least one axis, and the EPE can increase the eye box in an axis that intersects (e.g., is orthogonal) to the axis of the OPE. For example, each OPE can be configured to redirect a portion of the light reaching the OPE to the EPE of the same waveguide, while allowing the remainder of the light to continue to propagate along the waveguide. Upon impinging on the OPE again, another portion of the remaining light is redirected to the EPE, and the remainder of that portion continues to propagate further along the waveguide, and so on. Similarly, upon reaching the EPE, a portion of the impinging light is directed out of the waveguide toward the user, and the remainder of the light continues to propagate through the waveguide until it reaches the EPE again, at which time another portion of the impinging light is directed out of the waveguide, and so on. Therefore, whenever a portion of a single beam of coupled-in light is redirected by an OPE or EPE, that light can be "copied," thereby forming a field of cloned beams, such as Figure 6 As shown. In some embodiments, the OPE and / or EPE can be configured to modify the size of the light beam.

[0160] Therefore, reference Fig. 9A and Fig. 9B, in some embodiments, the waveguide group 660 includes: waveguides 670, 680, 690; coupling-in optical elements 700, 710, 720; light distribution elements (e.g., OPE) 730, 740, 750; and coupling-out optical elements (e.g., EP) 800, 810, 820 for each component color. The waveguides 670, 680, 690 can be stacked with an air gap / cladding between each waveguide. The coupling-in optical elements 700, 710, 720 redirect or deflect the incident light (where different coupling-in optical elements receive light of different wavelengths) into their waveguides. The light then propagates at an angle that will cause TIR within the corresponding waveguide 670, 680, 690. In the example shown, light ray 770 (e.g., blue light) is deflected by the first coupling-in optical element 700 and then continues to bounce along the waveguide, interacting with the light distribution element (e.g., OPE) 730 and the coupling-out optical element (e.g., EP) 800 in the manner previously described. Light ray 780 and light ray 790 (e.g., green light and red light, respectively) are transmitted through the waveguide 670, where light ray 780 impinges on and is deflected by the coupling-in optical element 710. Light ray 780 then bounces along the waveguide 680 via TIR, proceeds to its light distribution element (e.g., OPE) 740, and then to the coupling-out optical element (e.g., EP) 810. Finally, light ray 790 (e.g., red light) is transmitted through the waveguide 690 and impinges on the coupling-in optical element 720 of the waveguide 690. The light incoupling optical element 720 deflects the light 790 so that it propagates through TIR to the light distribution element (e.g., OPE) 750, and then propagates through TIR to the outcoupling optical element (e.g., EP) 820. The outcoupling optical element 820 then finally couples the light 790 out to the viewer, who also receives the outcoupled light from the other waveguides 670, 680.

[0161] Fig. 9C Shows Fig. 9A and Fig. 9B A top plan view of an example of multiple stacked waveguides. As shown, the waveguides 670, 680, 690 and the associated light distribution elements 730, 740, 750 and associated coupling-out optical elements 800, 810, 820 of each waveguide can be vertically aligned. However, as discussed herein, the coupling-in optical elements 700, 710, 720 are not vertically aligned; instead, the coupling-in optical elements are preferably non-overlapping (e.g., laterally spaced apart when viewed in a top view). As further discussed herein, this non-overlapping spatial arrangement facilitates one-to-one injection of light from different resources into different waveguides, thereby allowing a particular light source to be uniquely coupled to a particular waveguide. In some embodiments, arrangements including non-overlapping spatially separated coupling-in optical elements can be referred to as shifted pupil systems, and the coupling-in optical elements within these arrangements can correspond to sub-pupils.

[0162] Fig.9D An example of a wearable display system 60 is shown in which the various waveguides and related systems disclosed herein can be incorporated. In some embodiments, the display system 60 is Figure 6 The system 250, wherein Figure 6 Certain components of the system 60 are schematically shown in greater detail. For example, Figure 6 The waveguide assembly 260 can be part of the display 70.

[0163] Continue to refer Fig.9D , the display system 60 includes a display 70, and various mechanical and electronic modules and systems that support the functions of the display 70. The display 70 can be coupled to a frame 80 that can be worn by a display system user or viewer 90, and the frame 80 is configured to position the display 70 in front of the eyes of the user 90. In some embodiments, the display 70 can be regarded as glasses. In some embodiments, a speaker 100 is coupled to the frame 80 and is configured to be located adjacent to the ear canal of the user 90 (in some embodiments, another speaker (not shown) can be optionally located adjacent to another ear canal of the user to provide stereo / shaped sound control). The display system 60 may also include one or more microphones 110 or other devices to detect sound. In some embodiments, the microphone is configured to allow the user to provide input or commands to the system 60 (e.g., selection of voice menu commands, natural language questions, etc.), and / or may allow audio communication with other people (e.g., with other users of similar display systems). The microphone can be further configured as a peripheral sensor to collect audio data (e.g., sounds from the user and / or the environment). In some embodiments, the display system may further include a peripheral sensor 120a, which may be separated from the frame 80 and attached to the body of the user 90 (e.g., on the head, torso, limbs, etc. of the user 90). In some embodiments, the peripheral sensor 120a may be configured to acquire data representing a physiological state of the user 90. For example, the sensor 120a may be an electrode.

[0164] Continue to refer Fig.9D, the display 70 is operably coupled to a local data processing module 140 via a communication link 130 (e.g., via a wired lead or wireless connection), and the local data processing module 140 can 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 in headphones, or removably attached to the user 90 in other ways (e.g., in a backpack configuration, in a belt-coupled configuration). Similarly, the sensor 120a can be operably coupled to the local processing and data module 140 via a communication link 120b (e.g., a wired lead or a wireless connection). The local processing and data module 140 can include a hardware processor and digital memory, such as non-volatile memory (e.g., flash memory or a hard drive), both of which can be used to assist in the processing, caching and storage of data. Optionally, the local processing and data module 140 can 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 (which may, for example, be operably coupled to the frame 80 or otherwise attached to the user 90), such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, radios, gyroscopes, and / or other sensors disclosed herein; 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 transmission to the display 70 after such processing or retrieval. The local processing and data module 140 may be operably coupled to the remote processing module 150 and the remote data repository 160 by communication links 170, 180, such as via a wired or wireless communication link, so that these remote modules 150, 160 are operably coupled to each other and can be used as resources for the local processing and data module 140. In some embodiments, the 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 radio, and / or a gyroscope. In some other embodiments, one or more of these sensors may be attached to the frame 80, or may be an independent structure that communicates with the local processing and data module 140 via a wired or wireless communication path.

[0165] Continue to refer Fig.9DIn some embodiments, the remote processing module 150 may include one or more processors configured to analyze and process data and / or image information, for example, including one or more central processing units (CPUs), graphics processing units (GPUs), dedicated processing hardware, etc. In some embodiments, the remote data repository 160 may include a digital data storage facility that may be obtained via the Internet or other network configurations in a "cloud" resource configuration. In some embodiments, the remote data repository 160 may include one or more remote servers that provide information to the local processing and data module 140 and / or the remote processing module 150, for example, information for generating augmented reality content. In some embodiments, all data is stored in the local processing and data module, and all calculations are performed, allowing for full autonomous use from the remote module. Optionally, an external system (e.g., a system of one or more processors, one or more computers) including a CPU, GPU, etc. may execute at least a portion of the processor (e.g., generating image information, processing data), and provide information to the modules 140, 150, 160, and receive information from these modules, for example, via a wireless or wired connection.

[0166] Liquid crystal materials for broadband adaptive wave plate lens assemblies

[0167] In general, liquid crystals have physical properties that are between conventional fluids and solids. Although liquid crystals are similar to fluids in some respects, unlike most fluids, the arrangement of molecules in liquid crystals exhibits a certain structural order. Different types of liquid crystals include thermotropic liquid crystals, lyotropic liquid crystals, and polymeric liquid crystals. Thermotropic liquid crystals disclosed herein can be realized in various physical states (e.g., phases), including nematic states / phases, smectic states / phases, chiral nematic states / phases, or chiral smectic states / phases.

[0168] As described herein, a liquid crystal in a nematic state or phase may have rod-like (rod-shaped) or disc-like (disc-shaped) organic molecules that have relatively little positional order and at the same time have long-range directional order, wherein the long axes of the molecules are approximately parallel. Thus, the organic molecules can flow freely with their center of mass positions randomly distributed as in a liquid, while still maintaining their long-range directional order. In some embodiments, a liquid crystal in a nematic phase may be uniaxial; that is, the liquid crystal has one preferred axis that is longer, while the other two axes are approximately equal. In some embodiments, the liquid crystal molecules are oriented along their long axis. In other embodiments, the liquid crystal may be biaxial; that is, in addition to being oriented along its long axis, the liquid crystal may also be oriented along a secondary axis.

[0169] As described herein, a liquid crystal in a smectic state or phase may have organic molecules that form relatively well-defined layers that are able to move over each other. In some embodiments, a liquid crystal in a smectic phase may be positionally ordered along one direction. In some embodiments, the long axis of the molecules may be oriented in a direction substantially perpendicular to the plane of the liquid crystal layer, while in other embodiments, the long axis of the molecules may be tilted relative to the direction perpendicular to the plane of the layer.

[0170] In this document and throughout the disclosure, nematic liquid crystals may be composed of rod-shaped molecules in which the long axes of adjacent molecules are roughly aligned with each other. To describe this anisotropic structure, a dimensionless unit vector called a director may be used. n To describe the preferred orientation direction of liquid crystal molecules.

[0171] In this document and throughout the disclosure, the azimuth or rotation angle is used Describes the rotation angle of the liquid crystal molecules around the layer normal direction or the axis perpendicular to the main surface of the liquid crystal layer, which is measured in a plane parallel to the main surface of the liquid crystal layer or substrate (for example, the xy plane) and between the alignment direction (for example, the elongation direction or the direction of the director) and the direction parallel to the main surface (for example, the y direction).

[0172] In this document and throughout the disclosure, when the rotation angle When angles such as are referred to as being substantially the same or different between different regions, it should be understood that the averages of these angles may be, for example, within about 0.1%, about 5%, or about 10% of each other, although in some cases the average angles may be larger.

[0173] As described herein, some liquid crystals in the nematic or smectic state may also exhibit a twist in the layer normal direction. Such liquid crystals are referred to as twisted nematic (TN) liquid crystals or twisted smectic (SN) liquid crystals. TN or SN liquid crystals may exhibit a twist of the molecules around an axis perpendicular to the director, with the molecular axis parallel to the director. When the degree of twist is large, the twisted liquid crystal may be referred to as being in a chiral phase or a cholesteric phase.

[0174] As described herein, TN or SN liquid crystals may be described as having a twist angle or net twist angle (φ), which may refer, for example, to the relative azimuthal rotation between the topmost and bottommost liquid crystal molecules across a specified length (e.g., thickness) of the liquid crystal layer.

[0175] As used herein, "polymerizable liquid crystal" may refer to a liquid crystal material that can be polymerized (eg, in situ photopolymerization), which may also be described herein as a reactive mesogen (RM).

[0176] In some embodiments, the liquid crystal molecules may be polymerizable and, once polymerized, may form a large network with other liquid crystal molecules. For example, the liquid crystal molecules may be linked to other liquid crystal molecules by chemical bonds or linking chemicals. Once joined together, the liquid crystal molecules may form liquid crystal domains that have substantially the same orientation and position as before being linked together. The term "liquid crystal molecules" may refer to liquid crystal molecules before polymerization and / or to liquid crystal domains formed by these molecules after polymerization. Once polymerized, the polymerized network may be referred to as a liquid crystal polymer (LCP).

[0177] In some embodiments, unpolymerized liquid crystal molecules or polymerizable liquid crystal molecules before being polymerized may have at least limited rotational freedom. These unpolymerized liquid crystal molecules can, for example, rotate or tilt under electrical stimulation that causes a change in optical properties. For example, by applying an electric field, some liquid crystal layers including unpolymerized liquid crystal molecules can be switched between one or more states having different diffraction or polarization change properties.

[0178] The inventors have recognized that the above-mentioned properties of liquid crystals or reactive mesogens (RMs) can be advantageously applied to various components of broadband switchable wave plates and wave plate lenses disclosed herein. For example, in some unpolymerized RMs, the orientation of the LC molecules can be changed after deposition, for example, by applying an external stimulus (e.g., an electric field). Based on this recognition, the inventors disclose herein wave plates and wave plate lenses that can be switched between multiple states by applying an external stimulus.

[0179] In addition, the inventors have recognized that, when unpolymerized, the orientation of LC molecules at the surface or interface of some LCs or RMs can be aligned by controlling the surface or interface on which the LC molecules are formed. For example, a stack of multiple LC layers can be formed, wherein by controlling the orientation of the LC molecules closest to the surface of the LC layer, the orientation of the immediately adjacent LC molecules in the next LC layer can be controlled, for example, to have the same orientation as the LC molecules closest to the surface in the previous LC layer, or to have the same orientation as the elongated microstructures in the adjacent layer. In addition, LC molecules between LC molecules at the surface or interface can be controlled to have a predetermined amount of twist. Based on the recognition of these and other properties (including birefringence, chirality, and ease of multilayer coating), the inventors disclose herein wave plates and wave plate lenses having useful properties, such as broadband capabilities with customized optical properties (such as diffraction efficiency, optical power, and polarization, etc.).

[0180] Display device with switchable broadband adaptive wave plate lens assembly

[0181] As mentioned above Figure 6As described, some display systems according to embodiments include a waveguide assembly 260, which is configured to form images at multiple virtual depth planes. The waveguide assembly 260 includes waveguides 270, 280, 290, 300, 310, respectively configured to propagate light by total internal reflection (TIR), and includes outcoupling optical elements 570, 580, 590, 600, 610, respectively configured to extract light from a corresponding one of the waveguides 270, 280, 290, 300, 310 by redirecting the light. Each of the waveguides 270, 280, 290, 300, 310 is configured to output light to form an image corresponding to a specific depth plane. The waveguide assembly 260 may also optionally include a plurality of lenses 320, 330, 340, 350 located between the waveguides to provide different optical powers to form images at different virtual depth planes.

[0182] exist Figure 6 In the illustrated embodiment of the waveguide assembly 260 in FIG. 1 , the number of depth planes can be proportional to the number of waveguides and lenses. However, the inventors have recognized various challenges associated with implementing a waveguide assembly configured to display images at multiple depth planes by having a proportional number of waveguides and lenses. For example, a large number of waveguides 270, 280, 290, 300, 310 and a large number of corresponding lenses 320, 330, 340, 350 can undesirably increase the overall thickness, weight, cost, and manufacturing challenges of the waveguide assembly 260. For example, when formed from conventional lens materials (e.g., glass), each of the lenses 320, 330, 340, 350 can add several millimeters or tens of millimeters of thickness and corresponding weight to the display. In addition, a large number of waveguides and lenses can produce undesirable optical effects on the user, such as relatively high absorption losses. Thus, on the one hand, the inventors have recognized the potential benefits in certain situations of a display system capable of producing images at multiple depth planes with a fewer number of waveguides, a fewer number of lenses, thinner and lighter waveguides and lenses, and / or a fewer number of lenses per waveguide.

[0183] Still reference Figure 6, it should be understood that lenses 320, 330, 340, 350 can be configured to form images at different depth planes by applying corresponding optical powers to light from waveguides 310, 300, 290 and 280. In various embodiments, the light coupled out of the waveguide may have a polarization, such as circular polarization. However, when the polarized light coupled out of the waveguide passes through a waveplate lens or waveplate formed by liquid crystal, less than 100% of the coupled out light transmitted therethrough may be optically affected, for example, diffractive divergence, convergence or change in polarization, resulting in a portion of the coupled out light passing through without being optically affected. Light that passes through the lens without being optically affected in this manner is sometimes referred to as leakage light. Leakage light may be undesirably focused, defocused or change polarization in the downstream optical path, or may not be affected at all. When a large portion of the light passing through the waveplate or waveplate lens constitutes leakage light, the user may experience undesirable effects, such as "ghost" images, which are one or more undesired images visible to the user at undesired depth planes. The inventors have recognized that, among other reasons, such light leakage may also originate from waveplate lenses or waveplates formed by liquid crystals configured to have relatively high diffraction efficiency over a relatively narrow wavelength range of the visible spectrum. Therefore, on the other hand, the inventors have recognized that there is a need for a broadband adaptive waveplate lens assembly that can produce images at multiple depth planes with less undesirable effects of light leakage over a relatively wide wavelength range in the visible spectrum. To meet these and other needs, various embodiments include a broadband adaptive waveplate lens assembly that includes a switchable waveplate lens or switchable waveplate based on liquid crystals configured to provide variable optical focal length. Waveplate lenses and waveplates formed by liquid crystals can provide various advantages to achieve these goals, including low thickness, light weight, and high molecular-level configurability. In various embodiments described herein, a display device is configured to form images at different virtual depth planes using a waveguide assembly that is configured to guide light in a lateral direction parallel to a waveguide output surface, and to couple the guided light out to one or more broadband adaptive waveplate lens assemblies through the output surface. In various embodiments, a broadband adaptive waveplate lens assembly is configured to couple into and diffract outcoupled light from a waveguide. The broadband adaptive lens assembly includes a first waveplate lens, which includes a liquid crystal (LC) layer, and the liquid crystal layer is arranged so that the waveplate lens has a birefringence (Δn) that varies in a direction radially outward from a central region of the first waveplate lens. The resulting waveplate lens can be configured to diffract the outcoupled light with a diffraction efficiency of greater than 90%, greater than 95%, or even greater than 99% over a broadband wavelength range including at least 450nm to 630nm. In some embodiments, the broadband adaptive waveplate lens assembly according to the embodiments is significantly lighter and thinner (micrometer level) compared to conventional lenses, and can advantageously provide variable optical power over a broadband wavelength range.Advantageously, these broadband adaptive lens assemblies can reduce the size of waveguide assemblies (such as waveguide assembly 260). Figure 6 )), and reduce or eliminate the unwanted effects caused by light leakage.

[0184] As used herein, optical power (P, also called dioptric power, focusing power, or converging power) refers to the degree to which a lens, mirror, or other optical system converges or diverges light. It is equal to the reciprocal of the focal length of the device: P = 1 / f. That is, a high optical power corresponds to a short focal length. The SI unit of optical power is the reciprocal meter (m -1 ), commonly referred to as diopter (D).

[0185] As described herein, a converging lens that focuses light passing therethrough is described as having positive optical power, while a diverging lens that defocuses light passing therethrough is described as having negative optical power. Without being bound by theory, when light passes through two or more thin lenses that are relatively close to each other, the optical power of the combined lens can be approximated as the sum of the optical powers of the individual lenses. Therefore, when light passes through a first lens having a first optical power P1 and further passes through a second lens having a second optical power P2, the light can be understood as converging or diverging according to the sum of the optical powers Pnet=P1+P2.

[0186] A medium having a refractive index that depends on the polarization and propagation direction of light is called birefringent (or birefringent). As described throughout this specification and as understood in the relevant industry, a birefringent medium is described as having an ordinary refractive index (n) when light has a polarization perpendicular to the optical axis of the birefringent medium. o ), when light has polarization parallel to the optical axis of the birefringent medium, the birefringent medium is described as having an extraordinary refractive index (n e ), and the difference in refractive index n between the birefringent materials e -n o It is called birefringence Δn. The phase delay of light in a material medium with birefringence Δn can be expressed as Γ=2πΔnd / λ, where λ is the wavelength of light and d is the thickness of the medium.

[0187] Typically, optically anisotropic materials (e.g., liquid crystals) exhibit positive dispersion of birefringence (Δn), where Δn decreases as the wavelength of light λ increases. Positive dispersion of Δn results in different phase retardations Γ=2πΔnd / λ at different λ. As disclosed herein, an anisotropic material exhibiting negative dispersion of birefringence (Δn) refers to a material in which the birefringence increases as the wavelength of light λ increases.

[0188] As described above, the wavelength dependence of the diffraction efficiency of a waveplate lens or waveplate can be an important consideration in reducing or minimizing various undesirable optical effects. As described herein, the diffraction efficiency (η) of a birefringent medium such as a liquid crystal layer can be expressed as η = sin 2 (πΔnd / λ), where Δn is the birefringence, λ is the wavelength, and d is the thickness. Since the phase delay of light propagating through the diffractive component varies with the wavelength of the conventional birefringent medium, some diffractive components including wave plate lenses and wave plates show a relatively narrow wavelength range or bandwidth in which the diffraction efficiency is sufficiently high in the visible light range. In contrast, the wave plate lenses and wave plates according to the embodiments show a relatively wide wavelength range or bandwidth in which the diffraction efficiency is sufficiently high in the visible spectrum for the various applications described herein.

[0189] According to various embodiments, a broadband wave plate lens or wave plate may be described as having a normalized bandwidth (Δλ / λ0), where λ0 is a center wavelength within a visible spectrum spanning a wavelength range of approximately 400 to 800 nm, the visible spectrum including one or more of: a red spectrum having a wavelength range of approximately 620 to 780 nm, a green spectrum having a wavelength range of approximately 492 to 577 nm, and a blue spectrum having a wavelength range of approximately 435 to 493 nm, and Δλ is a wavelength range centered about λ0 within which the diffraction efficiency exceeds 70%, 80%, 90%, 95%, 99%, or any value within a range bounded by these values.

[0190] According to various embodiments, when a wave plate lens or a wave plate is described as a broadband wave plate lens or a broadband wave plate, it should be understood as having an average, instantaneous, mean, median or minimum value of diffraction efficiency greater than 70%, 80%, 90%, 95%, 99% or a percentage within any of these values ​​within at least a portion of the visible spectrum spanning a wavelength range of approximately 400 to 800 nm (including one or more of the following: a red spectrum including wavelengths in a range of approximately 620 to 780 nm, a green spectrum including wavelengths in a range of approximately 492 to 577 nm, and a blue spectrum in a range of approximately 435 to 493 nm), or within a wavelength range defined by any wavelength in the visible spectrum within approximately 400 to 800 nm (e.g., 400 to 700 nm, 430 to 650 nm, or 450 to 630 nm).

[0191] Based on the relationship η=sin described above for diffraction efficiency 2(πΔnd / λ), when the ratio of Δn / λ has a relatively constant positive value, the broadband waveplate lens or waveplate has an efficiency for a fixed d. As described herein, a medium having a positive ratio of Δn / λ is referred to as having negative dispersion. According to an embodiment, the broadband waveplate lens or broadband waveplate described herein has negative dispersion, or the above-mentioned birefringence (Δn) that increases with increasing wavelength (λ) within a wavelength range.

[0192] According to various embodiments, a broadband waveplate lens or waveplate may be described as an instantaneous value, mean, median, minimum or maximum value of a ratio Δn / λ that is positive in any range of the above-mentioned visible spectrum. In addition, a broadband waveplate lens or waveplate has a relatively high ratio Δλ / λ0, where Δλ is a wavelength range in any range of the above-mentioned visible spectrum and λ0 is a central wavelength within Δλ. According to various embodiments, a high normalized bandwidth Δλ / λ0 may have a value of about 0.3 to 0.7, 0.4 to 0.7, 0.5 to 0.7, 0.6 to 0.7, or a value within any range defined by these values. In addition, a broadband waveplate lens or waveplate has a relatively constant ratio Δn / λ in various wavelength ranges within the above-mentioned visible spectrum. For example, the ratio Δn / λ may have a deviation (e.g., standard deviation) of no more than 30%, 20%, 10%, 5%, 1% or a percentage within any of these values ​​relative to the mean, median, minimum or maximum value of the ratio Δn / λ.

[0193] As described herein, a "transmissive" or "transparent" structure (e.g., a transparent substrate) can allow at least some (e.g., at least 20%, 30%, 50%, 70%, or 90%) of incident light to pass therethrough. Thus, in some embodiments, the transparent substrate can be a glass, sapphire, or polymer substrate. In contrast, a "reflective" structure (e.g., a reflective substrate) can reflect at least some (e.g., at least 20, 30, 50, 70, 90%, or more) of incident light therefrom.

[0194] Fig.10An example of a display device 1000 (e.g., a wearable display device) is shown, which includes one or more broadband adaptive lens components, such as a pair of broadband adaptive lens components 1004, 1008 with a waveguide component 1012 inserted in the middle in an optical path 1016. As described above, the waveguide component includes a waveguide configured to propagate light (e.g., visible light), for example, under total internal reflection, and couple out the light along an optical axis extending from a light output surface of the waveguide (e.g., a major surface of the waveguide) (e.g., along a direction perpendicular to the light output surface of the waveguide). In some embodiments, the light can be coupled out through a diffraction grating. Each of the broadband adaptive lens components 1004, 1008 can be configured to at least partially transmit the outcoupled light therein. In the embodiment shown, each of the adaptive lens components can be configured to receive the outcoupled light from the waveguide component 1012 and converge or diverge the outcoupled light in the direction of the optical axis. Each of the broadband adaptive lens assemblies 1004, 1008 includes a wave plate lens, the wave plate lens includes liquid crystals, and the liquid crystals are arranged so that the wave plate lens has a birefringence (Δn) that varies in a radial direction from a central region of the wave plate lens and increases or decreases with increasing wavelength (λ) in the visible spectrum range. The broadband adaptive lens assembly is configured to selectively switch between a plurality of states having different optical powers. The broadband adaptive lens assembly is configured to change the polarization state of outcoupled light passing therethrough when activated (e.g., electrically activated).

[0195] As described 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. Example optical properties that can be reversibly activated and deactivated include, among other properties, optical power (focal length), phase, polarization, polarization selectivity, transmittance, reflectivity, birefringence, and diffraction properties. In various embodiments, the adaptive lens assembly is capable of electrically changing the optical power and polarization state of light passing therethrough.

[0196] In the illustrated embodiment, each of the pair of broadband adaptive lens assemblies 1004, 1008 is configured to selectively switch between at least two states. In a first state, each is configured to pass outcoupled light therethrough without changing its polarization state, and in a second state, each is configured to change the polarization state of the outcoupled light passing therethrough. For example, in the second state, each of the broadband adaptive lens assemblies 1004, 1008 reverses the handedness of circularly polarized light, while in the first state, each of the broadband adaptive lens assemblies 1004, 1008 maintains the handedness of the circularly polarized light.

[0197] Still reference Fig.10, the display device 1000 further includes a waveguide component 1012 between the pair of adaptive lens components 1004, 1008. The waveguide component 1012 can be similar to the above Figure 6 The waveguide assembly 260 includes one or more waveguides similar to Figure 6 One or more waveguides 270, 280, 290, 300, 310 in. As described above, for example Figure 6 and 7 As described, the waveguide can be configured to propagate light under total internal reflection along a lateral direction parallel to the main surface of the waveguide. The waveguide can also be configured to couple out light, for example, in a direction perpendicular to the main surface of the waveguide.

[0198] Still reference Fig.10 , a first adaptive lens assembly 1004 of the pair of adaptive lens assemblies is disposed on a first side of a waveguide assembly 1012, such as a side of the world 510 observed by a 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, such as a side of the user's eye 210. As described below, the pair of configured adaptive lens assemblies provide the user with virtual content from the waveguide assembly 1012 and also provide a real-world view at multiple virtual depth planes. In some embodiments, there is no or little distortion due to the presence of the adaptive lens assemblies. As described below with respect to Fig.11A and 11B As described, when the first and second adaptive lens assemblies 1004, 1008 are activated, virtual content and real-world views are provided to the user.

[0199] Fig.11A and 11BAn example of a display device 1100A / 1100B is shown, each display device including an adaptive lens assembly that outputs image information to a user in operation. Display devices 1100A and 1100B in an unpowered state are structurally identical. Display device 1100A is used herein to describe outputting a virtual image to a user, while display device 1100B is used herein to describe transmitting a real-world image to a user via display device 1100B. Display device 1100A / 1100B includes a pair of switchable lens assemblies 1004, 1008 that are configured to be electrically activated, for example, by applying a voltage or current. In some embodiments, in a deactivated state (e.g., when no voltage or current is applied), each of the first and second switchable lens assemblies 1004, 1008 has a low optical power (e.g., approximately zero). In some embodiments, in an activated state (e.g., when a voltage or current is applied), the first adaptive lens assembly 1004 on the world side can provide a first net optical power (Pnet1) having a first sign (e.g., positive optical power). When in an activated state, the second adaptive lens assembly 1008 on the user side can provide a second net optical power (Pnet2) having a second sign (e.g., negative optical power).

[0200] Fig.11A FIG. 1 shows a method of displaying virtual content to a user at a virtual depth plane according to some embodiments. Fig.10 As described above, the waveguide assembly 1012 between the pair of adaptive lens assemblies 1004, 1008 includes 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 couple light toward the eye 210 through, for example, a diffraction grating. The coupled light passes through the second adaptive lens assembly 1008 before entering the eye 210. When activated, the second adaptive lens assembly 1008 has a second net optical power Pnet2, which can have a negative value, so that the user sees a virtual image at the virtual depth plane 1104.

[0201] In some embodiments, the second adaptive lens assembly 1008 can be electrically adjusted to adjust the second net optical power (Pnet2) of the second adaptive lens assembly 1008 to adjust the distance to the virtual depth plane 1104. For example, when a virtual object "moves" closer or farther relative to the eye 210 in the virtual three-dimensional space, the second net optical power Pnet2 of the second adaptive lens assembly 1008 can be adjusted accordingly so that the virtual depth plane 1104 is adjusted to track the virtual object. As a result, the user may experience a relatively small accommodation / vergence mismatch that exceeds an acceptable threshold, or may not experience any accommodation / vergence mismatch. In some embodiments, the size of the distance to the virtual depth plane 1104 can be adjusted in discontinuous steps, while in some other embodiments, the size of the distance to the virtual depth plane 1104 can be adjusted continuously.

[0202] Fig. 11B An illustration showing providing a view of real-world content to a user according to some embodiments Fig.10 An example of a display system of . When the second adaptive lens component 1008 is activated to have a second net optical power (Pnet2) so as to display virtual content at the virtual depth plane 1104, light from the real world passing through the second adaptive lens component 1008 may also be converged or diverged according to Pnet2 of the activated second adaptive lens component 1008. Therefore, objects in the real world may appear out of focus. In order to mitigate this distortion, according to an embodiment, when activated, the first and second adaptive lens components 1004, 1008 may be configured to have optical powers with opposite signs. In some embodiments, the light passing through the first and second adaptive lens components 1004, 1008 converges or diverges according to the combined optical power, the size of which is approximately the difference between the sizes of the first and second net optical powers Pnet1, Pnet2 of the first and second adaptive lens components 1004, 1008. In some embodiments, the waveguide component 1012 may also have an optical power, and the adaptive lens component 1008 may be configured to address the distortion caused by both the lens component 1004 and the waveguide component 1012. For example, the sign of the optical power of adaptive lens assembly 1008 can be opposite to the sum of the optical powers of lens assembly 1004 and waveguide assembly 1012.

[0203] In some embodiments, the first adaptive lens assembly 1004 is configured to have a first net optical power Pnet1 that is close in magnitude to or the same as a second net optical power Pnet2 of the second adaptive lens assembly 1008, but has an opposite sign to Pnet2. Therefore, when the first and second adaptive lens assemblies 1004, 1008 are activated simultaneously, objects in the real world appear relatively unaffected by the optical power of the second adaptive lens assembly 1008 provided for displaying virtual content.

[0204] In some embodiments, the first adaptive lens assembly 1004 may be configured such that, when activated, the first net optical power Pnet1 dynamically matches the second net optical power Pnet2 of the second adaptive lens assembly 1008. For example, when the optical power Pnet1 of the second switchable assembly 1008 is adjusted to track a moving virtual object within a virtual three-dimensional space, the first net optical power Pnet1 of the first adaptive lens assembly 1004 may be dynamically adjusted so that the magnitude of the combined optical power P=Pnet1+Pnet2 may be maintained less than a predetermined value. Therefore, according to an embodiment, the second net optical power (Pnet2) of the second adaptive lens assembly 1008, which may have a negative value, may be compensated by using the first net optical power (Pnet1) of the first adaptive lens assembly 1004 so that the combined optical power P=Pnet1+Pnet2 remains small (e.g., close to about 0 m). -1 ) to prevent real-world objects from appearing unacceptably out of focus.

[0205] Switchable wave plates and switchable wave plate lenses for broadband adaptive wave plate lens assemblies

[0206] As described above, the advantages of forming images at multiple depth planes with fewer waveguides include display devices (e.g., Fig.10 The overall reduction in thickness and weight of the display device 1000 in FIG. 1000 is achieved. Thus, the various embodiments described herein provide a compact, lightweight adaptive wave plate lens assembly and provide various optical functions, such as high bandwidth capability and variable optical power. In addition, the various embodiments described herein provide an adaptive lens assembly with a relatively small amount of light leakage.

[0207] In order to provide images at multiple depth planes with high efficiency over a wide visible spectral range, a broadband adaptive lens assembly according to various embodiments includes a wave plate lens (respectively Fig. 12A , 12B1154A, 1154B in, the wave plate lens includes a liquid crystal, and the liquid crystal is arranged so that the wave plate lens has a birefringence (Δn) that varies in a radial direction from a central region of the first wave plate lens and increases or decreases with an increase in wavelength (λ) in the visible spectrum range. As described above, according to various embodiments, a broadband adaptive wave plate lens assembly can generate images at multiple depth planes by being configured to selectively switch between multiple states with different optical powers. As discussed herein, the selective switching of the broadband lens assembly can be performed by switching a wave plate lens or a wave plate included in a broadband adaptive wave plate lens assembly according to an embodiment.

[0208] refer to Fig. 12A In some embodiments, the broadband adaptive lens assembly 1150A is configured to switch between different optical power states by employing a switchable wave plate 1158 located in the same optical path as the wave plate lens 1154A, the switchable wave plate 1158 comprising a liquid crystal. The wave plate lens 1154A can be a passive lens, and the broadband adaptive lens assembly 1150A can be selectively switched between different states by electrically activating and deactivating the switchable wave plate 1158.

[0209] Still reference Fig. 12A According to various embodiments, in operation, the wave plate lens 1154A is configured to diverge or converge incident light 1162A, 1162B passing therethrough depending on the polarization (e.g., circular polarization) of the light. When configured as a half-wave plate (HWP) lens, the illustrated wave plate lens 1154A (which may be a passive wave plate lens) is configured to converge a right-handed circularly polarized (RHCP) light beam 1162B incident on the wave plate lens 1154A into a left-handed circularly polarized (LHCP) light beam 1166A. On the other hand, the wave plate lens 1154A is configured to diverge an LHCP light beam 1162A incident on the wave plate lens 1154A into a right-handed circularly polarized (RHCP) light beam 1166B.

[0210] Still reference Fig. 12A, after being focused or defocused by the wave plate lens 1154A according to the circular polarization of the light incident thereon, the LHCP beam 1166A or the RHCP beam 1166B is incident on the switchable wave plate 1158. The liquid crystal of the switchable wave plate 1158 is configured so that when activated (e.g., electrically activated), the polarization of the circularly polarized light passing therethrough is maintained (not shown). That is, the LHCP beam 1166A and the RHCP beam 1166B pass through the switchable wave plate 1158 unaffected. On the other hand, when deactivated (e.g., electrically activated), the polarization of the circularly polarized light passing therethrough is changed or flipped (shown). That is, the LHCP beam 1166A is transformed into the RHCP beam 1170A, and the RHCP beam 1166B is transformed into the LHCP beam 1170B.

[0211] refer to Fig. 12B In some other embodiments, the broadband adaptive lens assembly 1150B is configured to switch between different optical power states by employing a switchable wave plate lens 1154B comprising liquid crystal. The adaptive lens assembly 1150B can be selectively switched between different states by electrically activating and deactivating the switchable wave plate lens 1154B.

[0212] According to various embodiments, in operation, the liquid crystal of the wave plate lens 1154B is configured such that the wave plate lens 1154B diverges or converges incident light 1162A, 1162B passing therethrough depending on the polarization (e.g., circular polarization) of the incident light. When configured as a half-wave plate lens, when deactivated (e.g., electrically deactivated), the wave plate lens 1154B shown is configured to converge the RHCP light beam 1162B incident on the wave plate lens 1160B into the LHCP light beam 1166A. Conversely, when deactivated, the wave plate lens 1154B is configured to diverge the left-handedly polarized (LHCP) light beam 1162A incident on the wave plate lens 1154B into the RHCP light beam 1166B. On the other hand, when activated (e.g., electrically deactivated), the polarization of the circularly polarized light passing therethrough is maintained or unaffected (not shown), and the LHCP light beam 1162A and the RHCP light beam 1162B incident thereon pass through the wave plate lens 1154B without substantially converging or diverging, without having their polarization states affected. In various embodiments, the wave plate lens assemblies 1150A, 1150B may be activated or deactivated to converge or diverge according to the polarization of the circularly polarized light, and to flip or maintain its polarization, by configuring the liquid crystal to rearrange in response to a switching signal (e.g., an electric field).

[0213] Broadband switchable wave plates

[0214] As described above, according to various embodiments, a broadband adaptive wave plate lens assembly can be used to generate images at multiple depth planes by selectively switching the broadband wave plate lens assembly between multiple lens states with different optical powers. As described above, in some embodiments, the broadband adaptive wave plate lens assembly can be configured to selectively switch between multiple lens states by electrically activating a broadband switchable wave plate included in the broadband adaptive wave plate lens assembly. Hereinafter, embodiments of such a broadband switchable wave plate are disclosed.

[0215] In some embodiments, a broadband switchable wave plate includes an unpolymerized twisted nematic (TN) liquid crystal (LC) layer and is configured to switch when an electric field is applied across the entire thickness of the TN LC layer. Without being bound by any theory, switching may be achieved by changing the orientation of the unpolymerized LC molecules across the entire thickness of the TN LC layer.

[0216] refer to Figures 13A to 13F According to various embodiments, a broadband switchable wave plate includes a twisted nematic (TN) liquid crystal (LC) layer. Fig.13A A cross-sectional view of an example of a switchable wave plate comprising a TN LC layer is shown. The TN LC switchable wave plate 1300A comprises a TN LC layer 1302 disposed between a pair of transparent substrates 1312. Each of the transparent substrates 1312 has a conductive transparent electrode 1316, 1320 formed on an inner surface thereof.

[0217] The surfaces of the transparent electrodes 1316, 1320 and / or the substrate 1312 may be configured such that the TN LC molecules in contact with or in close proximity to the upper electrode 1316 tend to be oriented with their long axes extending in a first lateral direction, while the TN LC molecules in contact with or in close proximity to the lower electrode 1320 tend to be oriented with their long axes extending in a second lateral direction, which may intersect the first lateral direction, for example, forming an angle of about 90 degrees relative to the first lateral direction. The TN LC molecules between the TN LC molecules in close proximity to the lower electrode 1320 and the TN LC molecules in close proximity to the upper electrode 1316 are twisted. The TN LC switchable wave plate 1300A shown is configured as a broadband wave plate.

[0218] Still reference Fig.13A, in operation, in the absence of an electric field across the TN LC layer 1302 (deactivated state), the nematic directors of the TN LC molecules are smoothly twisted 90 degrees across the thickness of the TN LC layer 1302. In this state, incident light 1308 polarized in a first direction (the same direction as the LC molecules closest to the lower electrode 1312, indicated by a double-headed arrow) is incident on the TN LC layer 1302. The twisted arrangement of the LC molecules within the TN LC layer 1302 acts as an optical waveguide and rotates the polarization plane by a quarter turn (90 degrees) before reaching the upper electrode 1316. In this state, the TN LC layer 1302 acts to change the polarization direction of linearly polarized light passing therethrough from one linear polarization direction to another linear polarization direction. As a result, the transmitted light 1304A is polarized in a second direction (the same direction as the LC molecules closest to the upper electrode 1316) that is opposite to the first direction.

[0219] On the other hand, when a voltage exceeding the threshold voltage (V>Vth) of the TN LC switchable wave plate 1300A is applied across the electrodes 1316, 1320 (activated state), the TN LC molecules within the TN LC layer 1306 tend to align with the generated electric field and lose the optical waveguide properties of the TN LC layer 1304 described above with respect to the deactivated state. In this state, the TN LC layer 1306 serves to maintain the polarization direction of light passing therethrough. Therefore, the incident light 1308 and the transmitted light 1304B are polarized in the same first direction (the same direction as the LC molecules closest to the lower electrode 1312).

[0220] Still referring to the actuated state, when the voltage or electric field is turned off, the TN LC molecules relax back to their twisted state and the TN LC molecules of the TN LC layer 1306 in the actuated state return to the configuration of the TN LC molecules of the TN LC layer 1302 in the deactuated state.

[0221] As mentioned above, the above Fig.13A The TN LC switchable wave plate 1300A described herein is used to change the polarization direction of linearly polarized light. However, various broadband wave plate lens assemblies described herein include a switchable wave plate configured as a switchable half-wave plate for reversing the handedness of circularly polarized light. Figures 13B to 13D Hereinafter, a switchable wave plate configured as a switchable half-wave plate is described according to an embodiment.

[0222] Fig. 13B FIG. 1 shows a cross-sectional view of a switchable broadband wave plate 1300B configured as a half-wave plate according to an embodiment. The switchable broadband wave plate 1300B includes Fig.13AThe TN LC switchable wave plate 1300A is shown. In addition, the switchable broadband wave plate 1300B further includes a pair of achromatic quarter wave plates (QWP) 1324, 1326 in order to function as a broadband half wave plate for circularly polarized light.

[0223] In operation, in the activated state of the switchable broadband wave plate 1300B ( Fig. 13B ), when an incident circularly polarized light beam 1324 having a first handedness (e.g., a left-handed circularly polarized (LHCP) light beam) passes through the first QWP 1324, the first QWP 1324 transforms the circularly polarized light beam 1324 into a first linearly polarized light beam 1328 having a first linear polarization. Subsequently, when passing through the activated TN LC switchable wave plate 1300A, the first linearly polarized light beam 1328 is transformed into a second linearly polarized light beam 1332 having a second linear polarization. Next, when passing through the second QWP 1326, the second linearly polarized light beam 1332 is transformed into an outgoing circularly polarized light beam 1340 having a second handedness opposite to the first handedness, for example, into a RHCP light beam. Therefore, when activated, the switchable broadband wave plate 1300B acts as a half-wave plate that reverses the polarization of the circularly polarized light beam.

[0224] On the other hand, when the switchable broadband wave plate 1300B is deactivated ( Fig. 13B ), after the incident circularly polarized light beam 1324 passes through the first QWP 1324 as described above and then passes through the deactivated TN LC switchable wave plate 1300A, the polarization of the first linearly polarized light beam 1328 is maintained. Thereafter, when passing through the second QWP 1326, the first linearly polarized light beam 1328 is transformed into an outgoing circularly polarized light beam 1340 having a first handedness, for example, into an LHCP beam. Therefore, when deactivated, the broadband wave plate 1300B acts as a transparent medium that maintains the polarization of the circularly polarized light beam.

[0225] In various embodiments described herein, the first and / or second QWP 1324, 1326 are broadband quarter wave plates having similar bandwidths compared to the TN LC switchable wave plate 1300A. According to an embodiment, the quarter wave plates 1324, 1326 may be formed using polymeric TN LC layers. In order to provide broadband capabilities, the QWP according to various embodiments includes multiple TN LC layers. When each of the TN LC layers is formed on its own substrate, the resulting broadband quarter wave plate and / or the resulting stacked light absorption becomes unacceptably thick. Therefore, in the following, embodiments of QWPs including multiple TN LC layers formed on a single substrate are described for efficient integration with the TN LC switchable wave plate 1300A.

[0226] Fig. 13CA cross-sectional view of a broadband QWP 1300C is shown, which may be the broadband QWP 1300C described above. Fig. 13B The first and / or second QWP 1324, 1326 shown includes a plurality (M) of TN LC layers 1302-1, 1302-2, ... 1302-M stacked on an alignment layer 1302-0 formed on a substrate 1312. The alignment layer 1302-0, which is further described elsewhere in this specification, is configured to induce the elongation direction of LC molecules in the first TN LC layer 1302-1 that are immediately adjacent to the alignment layer 1302-0 to be aligned in a first direction. The LC molecules above the LC molecules aligned by the alignment layer 1302-0 are successively first twisted, so that the LC molecules in the first TN LC layer 1302-1 that are farthest from the alignment layer 1302-0 (immediately adjacent to the second TN LC layer 1302-2) are elongated in a second direction. The alignment of the LC molecules in each of the subsequent TN LC layers 1302-2 to 1302-M is aligned in a similar manner to the first TN LC layer 1302-1, except that the LC molecules closest to the previous layer are aligned in the same direction as the topmost LC molecules of the previous layer. For example, the topmost LC molecules in the first TN LC layer 1302-1 and the bottommost LC molecules in the second TN LC layer 1302-2 are aligned in the same second direction. The LC molecules in the second TN LC layer 1302-2 undergo a second twist, so that the topmost LC molecules in the second TN LC layer 1302-2 are elongated in a third direction. This alignment of the LC molecules in a given TN LC layer caused by the alignment of the LC molecules in the adjacent layers in contact is sometimes referred to as self-alignment because no intermediate alignment layer is interposed between them. Therefore, in some embodiments, the broadband QWP includes a plurality of TN LC layers having two or more self-aligned TN LC layers, each of which has a non-zero twist.

[0227] In an embodiment, the TN LC layer includes polymerized LC molecules (LCP) formed using, for example, a reactive mesogen. As described above, the reactive mesogen is initially a low molecular weight LC, which, like a conventional LC, can be aligned through surface and distortion to have a complex distribution, but the low molecular weight LC is then cured into a solid polymer film by, for example, photopolymerization.

[0228] Fig.13D A cross-sectional view of an integrated switchable broadband wave plate 1300D is shown, wherein the Fig.13A A TN LC switchable wave plate 1300A similar to the TN LC switchable wave plate described above is integrated into a Fig. 13CA pair of broadband QWPs are depicted in a single stack of a similar pair of broadband QWPs 1324, 1326. In the embodiment shown, the TNLC switchable waveplate 1300A is integrated into a single stack by attaching the pair of broadband quarter waveplates 1324, 1326 on opposite sides of the single stack using adhesive layers 1348.

[0229] Fig.13E A cross-sectional view of an integrated switchable broadband wave plate 1300E is shown, wherein the Fig.13D A similar approach would be similar to the one described above regarding Fig.13A The TN LC switchable wave plate 1300A is described as being integrated into a single stack with a pair of broadband quarter wave plates 1324, 1326, but instead of using an adhesive to form the integrated stack, one of the pair of broadband quarter wave plates 1324, 1326 is used as an adhesive on which the TN LC switchable wave plate 1300A can be directly formed. Fig.13A ) substrate. For example, on the surface of one or both of the QWPs 1324, 1326, the different layers of the TN LC switchable wave plate 1300A may be formed directly. Advantageously, one or both of the substrates 1312 of the TN LC switchable wave plate 1300A may be omitted. Thus, the TN LC switchable wave plate 1300A is integrated into a compact single stack by being formed directly on one of the pair of broadband QWPs 1324, 1326 and then forming the other of the pair of broadband QWPs 1324, 1326 thereon.

[0230] In the above about Fig.13D and 13E In each of the embodiments shown, the broadband QWP can be formed from liquid crystal based materials or other non-liquid crystal based materials (e.g., quartz and MgF2). Fig.13F , showing an embodiment in which a broadband QWP comprising liquid crystals is particularly advantageously integrated with a TN LC switchable wave plate into a single stack to function not only as a QWP but also as an alignment layer of the TN LC switchable wave plate.

[0231] Fig.13F 13 shows a cross-sectional view of an integrated switchable broadband wave plate 1300F that integrates a TN LC switchable wave plate similar to that described above with respect to FIG. 13. The switchable broadband wave plate 1300F includes a pair of broadband QWPs 1324, 1326 that are arranged in the same manner as described above with respect to FIG. Fig.13EThe arrangement is similar to that described above, but instead of broadband QWPs 1324, 1326 as substrates for the TN LC layer 1302, the broadband QWPs 1324, 1326 include thin polymerized LC layers formed on respective surfaces of a substrate 1312. The LC molecules of the TN LC layer 1302 are inserted into the gaps formed between the opposing surfaces of the broadband QWPs 1324, 1326 by spacers 1350 that define the thickness of the TN LC layer 1302. The method of inserting the LC molecules is further described elsewhere in the specification. In addition, the different layers of the TN LC switchable wave plate 1300A and the different layers of the broadband QWPs 1324, 1326 are integrally formed as a single stack. For example, the first broadband QWP 1324 includes a substrate 1312 with a lower transparent electrode 1316 formed thereon, followed by an alignment layer 1302-0 and a plurality of TN LC layers 1302-1, 1302-2. Similarly, the second broadband QWP 1326 comprises a substrate 1312 having an upper transparent electrode 1320 formed thereon, followed by an alignment layer 1302-0 and a plurality of TN LC layers 1302-1, 1302-2.

[0232] Still reference Fig.13F Advantageously, the outermost LC molecules of the TN LC layer 1302-2 of the first broadband QWP 1324 facing the gap and the outermost LC molecules of the TN LC layer 1302-2 of the second broadband QWP 1326 facing the gap are arranged to serve as an alignment layer for the switchable TN LC layer 1302, so that the outermost LC molecules of the TN LC layer 1302 are aligned in a manner similar to that described above with respect to Fig. 13C In addition, by integrally stacking different layers of the TN LC switchable wave plate 1300A and different layers of the broadband QWP 1324, 1326, the overall thickness of the entire stack can be significantly reduced. For example, although mechanical bonding Fig.13A The TN LC switchable wave plate 1300A shown is Fig. 13C The broadband quarter wave plates 1324, 1326 shown may result in up to four substrates, but the entire stack of switchable broadband wave plates 1300F has only two substrates.

[0233] refer to Fig.13FIn various embodiments throughout the specification, the switchable LC layer (e.g., the TN LC layer 1302 inserted in the gap) has a thickness of about 1 μm to 50 μm, 1 to 10 μm, 10 to 20 μm, 20 to 30 μm, 30 to 40 μm, 40 to 50 μm, or any range of values ​​defined by these values. In addition, the passive LC layer (e.g., the TN LC layers 1302-1, 1302-2) may have a thickness of about 0.1 μm to 50 μm, 0.1 to 1 μm, 1 to 10 μm, 10 to 20 μm, 20 to 30 μm, 30 to 40 μm, 40 to 50 μm, or any range of values ​​defined by these values.

[0234] In various embodiments described herein, the alignment layer (e.g. Fig. 13C , 13F 1302-0) in the embodiment is used to align the LC molecules, for example, to align the elongation direction of the LC molecules along a specific direction. FIG. 13A to FIG. 13F As described, the alignment layer can be used to define the director (n) or the local average elongation direction of the elongated LC molecules in a predetermined direction. In some other embodiments, the alignment layer can be formed of an organic polymer, such as mechanically rubbed polyimides and polyamides, obliquely deposited inorganic oxides (such as SiO2) or long-chain aliphatic siloxanes. In some embodiments, the non-contact alignment layer can be formed of an organic polymer, where plane polarized light is used to produce surface anisotropy, which in turn defines the director. For example, cis-trans photoisomerization using azo dyes that can be directly deposited or dissolved into standard alignment layers (such as polyimide) or LC mixtures can produce an aligning effect in the alignment layer without rubbing. Non-contact alignment layers using azo chromophores sometimes use strong lasers to induce isomerization of the dye molecules.

[0235] In some other embodiments, the pattern of nanostructures may be used as an alignment layer for aligning LC molecules. Advantageously, in some embodiments, the pattern of nanostructures may be formed as part of an electrode layer to improve light transmittance, reduce process steps, and / or further reduce, for example, the above-mentioned Figures 13A to 13F The total thickness of the broadband wave plate described by . To achieve this, Fig.14AA perspective view of a pattern of a nanostructure 1400A according to an embodiment is shown, the nanostructure 1400A is, for example, a nanowire formed on a transparent substrate 1312, which plays a dual role as an alignment layer and an electrode layer. The pattern of the nanostructure 1400A can be patterned on the substrate 1312 using, for example, a lithography or nanoimprinting technique described in detail elsewhere in this specification. The nanostructure can be formed by a sufficiently thin conductive material patterned as an elongated metal wire. For example, the conductive material can be gold, silver, copper, aluminum or ITO or any suitable conductive material, the thickness and resistivity of the suitable conductive material making the resulting nanostructure pattern can be used as an alignment layer and an electrode layer at the same time. In the illustrated embodiment, the pattern of the nanostructure 1400A includes periodic wires 1404A extending in a first direction (e.g., x direction), which are connected to a rail 1408A to which a current or voltage is supplied. In various embodiments, the periodic wire 1404A may have a spacing of 1 μm to 1000 μm, 5 μm to 500 μm, 10 μm to 100 μm, or any value within the range defined by these values. The wire 1404 may have a width of 10 nm to 1 μm, 100 nm to 1000 nm, 100 nm to 500 nm, 200 nm to 300 nm, or any value within the range defined by these values. The periodic wire 1404 may have a thickness of 10 nm to 1 μm, 100 nm to 1000 nm, 100 nm to 500 nm, 400 nm to 500 nm, or any value within the range defined by these values. The combination of material, thickness, and width of the periodic wire 1404A may be selected so that the sheet resistance of the resulting periodic wire 1404A is about 1 ohm / s. Up to 100 ohms / , 2 ohms / Up to 50 ohms / , 5 ohms / Up to 20 ohms / or any value within the range defined by these values, such as about 10 ohms / In addition, the combination of material and thickness of the conductor 1404A can be selected so that the resulting transmittance in the visible spectrum is 80% to 99%, 90% to 99%, 95% to 99%, 97% to 99%, or any value within the range bounded by these values, such as about 98%. Other sizes, configurations, and values ​​are also possible.

[0236] Fig. 14B A perspective view of a pattern of nanostructures 1400B is shown, which is similar to the pattern of nanostructures 1400B described above. Fig.14AThe pattern of nanostructure 1400A is depicted except that the pattern of nanostructure 1400B includes periodic conductive lines 1404B extending in a second direction (eg, the x-direction), the periodic conductive lines 1404B being connected to tracks 1408B for supplying current thereto.

[0237] Fig. 14C 14 shows a perspective view of a pair of electrodes 1400C according to an embodiment. The pair of electrodes 1400C includes a pattern of nanostructures 1400A ( Fig.14A ) and the pattern of nanostructure 1400B ( Fig. 14B ), these patterns are arranged such that the periodic wires 1404A and the periodic wires 1404B face and cross each other and are separated by a gap 1412, which is configured to arrange one or more LC layers, such as TN LC layers, therein. Advantageously, it has been found that each of the patterns of nanostructures 1400A and 1400B can be used as described above with respect to Fig. 13C , 13F An alignment layer similar to the alignment layer 1302-0 described above is formed so that when nematic LC molecules (e.g., reactive mesogens) are formed thereon, LC molecules immediately adjacent to each of the patterns of nanostructures 1400A and 1400B can become aligned, for example, wherein the directors of the nematic LC molecules are approximately aligned in the same direction as the elongation direction of the periodic wires 1404A, 1404B. In addition, LC molecules between LC molecules immediately adjacent to the periodic wires 1404A, 1404B can be configured to be twisted using a twisting agent so that the same alignment as described above with respect to the periodic wires 1404A, 1404B can be formed. Fig.13A An unpolymerized TN LC layer similar to the TN LC layer 1302 described above, and Fig. 13C The depicted TN LC layers 1302-1, 1302-2, ... 1302-M are similar polymeric TN LC layers.

[0238] Return to reference Fig.13F It should be understood that in some embodiments, by combining the functions of the electrodes and the alignment layers, the pattern of nanostructures 1400A can replace the combination of the transparent electrode 1316 and the alignment layer 1302-0 of the broadband QWP 1324, and the pattern of nanostructures 1400B can replace the combination of the transparent electrode 1320 and the alignment layer 1302-0 of the broadband QWP 1326, thereby allowing a more compact overall stacking.

[0239] Still reference Fig. 14C , in operation, the arrangement of LC molecules with and without an electric field and the corresponding effect on the polarization of light is similar to that described above with respect to Fig.13A Describe the situation.

[0240] Fig.15A and15B 1 and 2 show a plan view and a cross-sectional view of a TN LC switchable broadband wave plate 1500 according to an embodiment. Fig.13A and Fig.13F Unlike the broadband wave plate shown with vertically separated switching electrodes, the TN LC switchable broadband wave plate includes in-plane laterally separated switching electrodes. The TN LC switchable broadband wave plate 1500 includes an alignment electrode stack 1524 and an alignment layer stack 1526. Fig.13F In a similar manner, LC molecules are inserted into the gap formed by the spacer 1350 between the opposite surfaces of the alignment electrode stack 1524 and the alignment layer stack 1526. The method of inserting LC molecules is described elsewhere in the specification. The alignment electrode stack 1524 includes the first and second electrodes 1500A, 1500B formed on the upper transparent substrate 1312, and further includes an optional upper alignment layer 1302-0. The alignment layer stack 1526 includes a lower alignment layer 1302-0 formed on the lower transparent substrate 1312.

[0241] refer to Fig.15A , the alignment electrode stack 1524 includes first and second electrodes 1500A, 1500B, which respectively include a corresponding one of the first and second periodic wires 1504A, 1504B. The periodic wires 1504A and the periodic wires 1504B are interdigitated or staggered and alternated. Each of the first and second periodic wires 1504A, 1504B is respectively arranged in the same manner as described above with respect to the patterned nanostructure 1400A ( Fig.14A )、1400B( Fig. 14B ) are tied to the tracks 1508A, 1508B in a similar manner. The materials, thickness, width and spacing of the alternating periodic wires 1504A, 1504B can be similar to those described above with respect to the patterned nanostructure 1400A ( Fig.14A )、1400B( Fig. 14B ) described above. However, Fig. 14C Unlike the depicted vertically separated pair of electrodes 1400C, the periodic wires 1504A alternate with the periodic wires 1504B in a lateral direction (eg, y-direction) such that the electric field between the periodic wires 1504A and the periodic wires 1504B is oriented in the lateral direction.

[0242] refer to Fig. 15B A cross-sectional view of a TN LC switchable unit 1500 in FIG. Fig.13F In a similar manner, LC molecules are inserted into the gap formed between the opposite surfaces of the alignment electrode stack 1524 and the alignment layer stack 1526, so that a TN LC layer 1302 ( Fig.13A) of a TN LC layer (not shown). Methods of inserting LC molecules are described elsewhere in the specification.

[0243] In some embodiments, the Fig. 14C In a similar manner, the alternating periodic wires 1504A, 1504B and / or the upper alignment layer 1302-0 in the alignment electrode stack 1524 may serve as an alignment layer for the outermost LC molecules of the TN LC layer 1302 formed in the gap 1412, in a manner similar to that described above with respect to Fig.13A The alignment layer 1316 described above is similar to the alignment layer 1316 described above. Fig. 14C When the alternating periodic wires 1504A, 1504B are used as alignment layers, in some embodiments, the upper alignment layer 1302-0 may be omitted. Fig.13A The alignment layer 1320 described above is similar to the alignment layer 1320 described above. Fig. 14C In a similar manner as described for the conductive line 1404A, the lower alignment layer 1302 - 0 may be used to align the LC molecules immediately adjacent thereto in the gap 1412 .

[0244] Although not shown, in some embodiments, the illustrated TN LC switchable broadband wave plate 1500 may integrate multiple TN LC layers similar to the TN LC layers 1302-1, 1302-2, .... 1302-M (between the alternating periodic conductive lines 1504A, 1504B and the LC molecules in the gap 1412, and / or between the lower alignment layer 1302-0 and the LC molecules in the gap 1412) in a manner similar to that described above with respect to FIG. 1300F. Fig.13F , not shown), so as to be consistent with the above Fig.13F A similar approach as described provides integrated QWP functionality.

[0245] Still reference Fig.15A , 15B In operation, in the absence of an electric field, the alternating periodic wires 1504A, 1504B act as an alignment layer for the LC molecules immediately adjacent to the periodic wires 1504A, 1504B, such that the LC molecules have directors extending substantially parallel to the periodic wires 1504A, 1504B. Fig.13AIn a similar manner, the switchable broadband wave plate 1500 is configured to flip the polarization of linearly polarized light. On the other hand, when an electric field is applied between the periodic wire 1504A and the periodic wire 1504B in a transverse direction (e.g., y direction), the LC molecules between the adjacent periodic wires 1504A, 1504B are aligned, wherein their elongation directions are in a direction deviating from parallel (e.g., between parallel and perpendicular) or perpendicular to the periodic wires 1504A, 1504B. In the activated state, the LC molecules are aligned in a direction similar to that described above with respect to the periodic wires 1504A, 1504B. Fig.13A In a similar manner, the switchable broadband wave plate 1500 is configured to maintain the polarization of linearly polarized light.

[0246] In some embodiments, in addition to the functions of the combined electrode and the alignment layer, the first and second electrodes 1500A, 1500B can, for example, replace the transparent electrodes 1316, 1320 and the broadband wave plate 1300F ( Fig.13F ) is a combination of upper and lower alignment layers 1302-2, thereby making the overall stack more compact due to the reduction of the electrode layer in half, and further improving the transmittance.

[0247] Liquid crystal based wave plate lenses

[0248] As mentioned above Fig. 12A As described, in order to efficiently provide images at multiple depth planes over a wide visible spectrum, some broadband adaptive wave plate lens assemblies according to embodiments include a switchable wave plate and one or more wave plate lenses, which may be passive or switchable, formed by a birefringent liquid crystal film. Hereinafter, an example wave plate lens including a liquid crystal is disclosed, wherein the orientation of the liquid crystal in the wave plate plane is suitable for focusing light transmitted therethrough and / or changing the polarization state of light transmitted therethrough. Hereinafter, various embodiments of lenses and wave plates formed by liquid crystals are described.

[0249] An example of a liquid crystal based wave plate lens Fig.16A and 16B Shown.

[0250] Fig.16A and 16B Examples of wave plate lenses 1200A and 1200B are shown, respectively, each of which includes a transparent substrate 1204 (e.g., a glass substrate) on which liquid crystal molecules 1208 are formed, and the liquid crystal molecules 1208 are elongated along different elongation directions relative to a direction parallel to an axial direction (e.g., an x-direction or a y-direction) along a major surface of the substrate 1204. That is, the liquid crystal molecules 1208 are rotated around a direction perpendicular to the major surface of the substrate 1204 (e.g., a z-direction) at different rotation angles (φ), where φ is described as an angle between the elongation direction of the liquid crystal molecules relative to a direction parallel to a layer normal (e.g., an x-direction or a y-direction).

[0251] In the illustrated embodiment, the liquid crystal molecules 1208 located at a given radius relative to the central axis C or the center of the lens have substantially the same rotation angle (φ). As arranged, the liquid crystal molecules 1208 are configured to focus the collimated light beam to a point at the focal length. Without being bound by any theory, the rotation angle (φ) of the liquid crystal molecules 1208 can be proportional to a power of r, where r is the radial distance from C, and has a value between about 1 and 3, such as 2. In one embodiment, the angle (φ) can be + / - k0r 2 / f, where r is the radial distance from C, and k0 = 2π / λ is the wave number of light to be focused by the diffractive wave plate lens, λ is the wavelength of light, and f is the focal length of the wave plate lens 1200A, 1200B. The + and - signs may correspond to the rotation direction of the liquid crystal molecules 1208 relative to the liquid crystal molecules 1208 closest to the center C of the wave plate lens 1200A, 1200B.

[0252] It should be understood that the patterns of the liquid crystal molecules 1208 of the wave plate lenses 1200A and 1200B represent flipped images of each other. That is, the other of the wave plate lenses 1200A and 1200B can be obtained by rotating one of the wave plate lenses 1200A and 1200B 180 degrees around an axial direction (e.g., the x-direction or the y-direction). As configured, the focal lengths and optical powers of the wave plate lenses 1200A and 1200B are the same in magnitude but opposite in sign.

[0253] In some embodiments, each of the wave plate lenses 1200A and 1200B can be used as a half-wave plate lens. When configured as a half-wave plate lens, each of the wave plate lenses 1200A and 1200B rotates the plane of linear polarized light by an angle of 2α relative to the polarization of the input beam, where α is the angle between the input polarization direction and the wave plate axis. For a circularly polarized beam, this angle change is converted into a phase shift and a reversal of the polarization handedness. Thus, a ±2α phase shift can be generated in the circularly polarized beam, where the sign of the phase shift depends on the polarization handedness.

[0254] Fig. 16C An example of an optical wave plate lens is shown that diverges or converges light passing therethrough depending on the polarization of the light and the incident side of the light, according to some embodiments. When configured as a half-wave plate lens, the illustrated wave plate lens 1200A can be configured to diverge a right-handed circularly polarized (RHCP) light beam 1212 incident on a first side into a left-handed circularly polarized (LHCP) light beam 1216. On the other hand, the wave plate lens 1200A can be configured to converge a RHCP light beam 1220 incident on a second side opposite to the first side into a left-handed circularly polarized (LHCP) light beam 1224.

[0255] For wave plate lens 1200B, the situation is the opposite. Fig.16DAs shown, when configured as a half-wave plate, the wave plate lens 1200B can be configured to converge the LHCP beam 1228 incident on the first side into the RHCP beam 1232. On the other hand, the wave plate lens 1200B can be configured to diverge the LHCP beam 1236 incident on the second side opposite to the first side into the RHCP beam 1240.

[0256] Thus, by controlling the rotation angle direction and radial distribution of the liquid crystal 1208, the wave plate lens can be configured to converge or diverge circularly polarized light with either handedness. It should be understood that based on the relationship between the liquid crystal rotation angles, the optical power can be increased or decreased. Additionally, in some embodiments, the liquid crystals can be aligned and misaligned by applying an electric field. Thus, it should be understood that in the limit where the optical power approaches zero, the wave plate lens can be used as a wave plate, such as a switchable wave plate.

[0257] Broadband adaptive wave plate lens assembly including switchable wave plates

[0258] As mentioned above Fig. 12A As described above, in order to efficiently provide images at multiple depth planes over a wide visible spectrum, some broadband adaptive wave plate lens assemblies according to embodiments include a switchable wave plate and one or more wave plate lenses, which may be passive or switchable, formed of a birefringent material (e.g., liquid crystal) film. In the following, embodiments of broadband adaptive wave plate lens assemblies including switchable broadband wave plates are disclosed. For example, the switchable broadband wave plate may be the above-mentioned Figures 13A to 13F , Figures 14A to 14C and Figures 15A to 15B One of the broadband switchable wave plates described.

[0259] Fig.17A An example of a broadband adaptive wave plate lens assembly 1700 including a wave plate lens (eg, a passive wave plate lens) and a switchable wave plate according to some embodiments is shown. The broadband adaptive wave plate lens assembly 1700 may be configured, for example, as described above with respect to Fig.10 , 11A Any of a pair of switchable wave plate assemblies 1004, 1008 described in and 11B. Fig. 17B Shows the activation Fig.17A The adaptive lens assembly 1700 shown in FIG. 1 is a broadband adaptive wave plate lens assembly 1700A that operates in the case of a switchable wave plate, while Fig. 17C Shows the deactivation Fig.17A The adaptive lens assembly 1700 is shown as a broadband adaptive wave plate lens assembly 1700B operating in the case of a switchable wave plate. The adaptive lens assembly 1700 is configured to couple and transmit therein the wave plate assembly 1012 ( Fig.10 , 11A, 11B) outcoupled light. The adaptive lens assembly 1700 includes a first wave plate lens (L1 / HWP1) 1704 (e.g., a first half-wave plate lens), a second wave plate lens (L2 / HWP2) 1708 (e.g., a second half-wave plate lens), and a switchable wave plate (HWP3) 1712 (e.g., a switchable half-wave plate).

[0260] In various embodiments, each of L1 / HWP1 1704 and L2 / HWP2 1708 is configured to function as a lens and a half-wave plate. Fig. 12A and 12B As described above, when configured as a half-wave plate, each of L1 / HWP1 1704 and L2 / HWP2 1708 is configured to transform circularly polarized light having a first handedness (first HCP) into circularly polarized light having a second handedness (second HCP). That is, each of L1 / HWP1 1704 and L2 / HWP2 1708 is configured to transform light passing therethrough from light having LHCP or RHCP into light having RHCP or LHCP, respectively.

[0261] In various embodiments, each of L1 / HWP1 1704 and L2 / HWP2 1708 is configured to function as a lens, having a first lens effect or a second lens effect opposite to the second lens effect for a given polarization. That is, each of L1 / HWP1 1704 and L2 / HWP2 1708 is configured to converge or diverge light passing therethrough. In various embodiments, each of L1 / HWP1 1704 and L2 / HWP2 1708 may be configured to have opposite lens effects, depending on the polarization state of the incident light. For example, each of L1 / HWP1 1704 and L2 / HWP2 1708 may be configured to focus light having a first HCP incident thereon, while being configured to defocus light having a second HCP incident thereon.

[0262] In some embodiments, L1 / HWP1 1704 and L2 / HWP2 1708 are configured to have the same lens effect for light having a given HCP. That is, both L1 / HWP1 1704 and L2 / HWP2 1708 can be configured to focus light having an LHCP, focus light having an RHCP, defocus light having an LHCP, or defocus light having an RHCP.

[0263] In some embodiments, each of L1 / HWP1 1704 and L2 / HWP2 1708 may include liquid crystal molecules that are elongated and rotated so that the liquid crystals located at a given radius from the central axis of each wave plate lens 1704, 1708 have the same rotation angle (φ), as described above with respect to Fig. 12Aand 12B Each of the first and second wave plate lenses 1704, 1708 is configured to change the polarization state of light passing therethrough, such as to invert the polarization state. The switchable wave plate 1712 is configured to change the polarization state of light passing therethrough, such as to invert the polarization state, when electrically deactivated, and is configured to substantially pass light through without changing the polarization state of light passing therethrough when activated. An electrical signal (e.g., a current signal or a voltage signal) for switching the switchable wave plate 1712 can be provided by a switch circuit 1716 electrically connected thereto.

[0264] In various embodiments, when deactivated (eg, electrically deactivated using a voltage or current signal provided by switch circuit 1716), HWP3 1712B ( Fig. 17C ) is used as a half-wave plate. That is, when deactivated, HWP3 1712B ( Fig. 17C ) is used as a half-wave plate configured to transform light passing therethrough from light having LHCP or RHCP to light having RHCP or LHCP, respectively. Thus, when deactivated, L1 / HWP1 1704, L2 / HWP2 1708, and HWP3 1712B ( Fig. 17C ) are each configured to convert circularly polarized light having a first handedness (first HCP) into circularly polarized light having a second handedness (second HCP).

[0265] In various embodiments, when activated (eg, electrically activated (eg, by removing the voltage or current signal) using a voltage or current signal provided by the switch circuit 1716), the HWP3 1712A ( Fig. 17B ) acts as a light transmitting medium without affecting polarization or providing any lens effect.

[0266] In some embodiments, a single wave plate lens 1704 and / or 1708 can be used as both a wave plate lens and a switchable half-wave plate. In such an embodiment, a dedicated switchable half-wave plate 1712 can be omitted.

[0267] Fig. 17B FIG. 1 shows an example of a switchable wave plate operating with the switchable wave plate activated according to some embodiments. Fig.17A1700A. When switchable wave plate 1712 is activated, for example when switch circuit 1716 does not apply current or voltage to switchable wave plate 1712, adaptive lens assembly 1700A can be activated. Adaptive lens assembly 1700A can correspond to first adaptive lens assembly 1004 (located on the world side) or second adaptive lens assembly 1008 (located on the user side). By way of example only, adaptive lens assembly 1700A will be described as corresponding to first adaptive lens assembly 1004 or second adaptive lens assembly 1008 as a display device 1000 (displaying a view of the real world to a user without displaying a virtual image) Fig.10 ). For example, the display device 1000 ( Fig.10 ) can be used as ordinary glasses or ordinary goggles. Each of L1 / HWP1 1704 and L2 / HWP2 1708 can be configured to have a first lens effect (e.g., diverging effect) on light having a first HCP (e.g., LHCP) passing therethrough. Each of L1 / HWP1 1704 and L2 / HWP2 1708 can also be configured to have a second lens effect (e.g., converging effect) opposite to the first lens effect on light having an opposite HCP (e.g., RHCP) passing therethrough.

[0268] In the illustrated embodiment, when the display device 1700A is used as ordinary glasses or goggles without displaying virtual content, the light beam 1720 can represent a light beam from the world that is incident on the first adaptive lens assembly 1004 ( Fig.11A / B, located on the world side) or the second adaptive lens assembly 1008 ( Fig.11A 1704, the light beam 1720 having the first HCP (e.g., LHCP) travels (e.g., travels in the positive z-direction) until the light beam 1720 impinges on and is transmitted through the L1 / HWP1 1704. The L1 / HWP1 1704 transforms the light beam 1720 having the LHCP into a light beam 1724 having the RHCP. Since the L1 / HWP1 1704 is also configured as a lens, the L1 / HWP1 1704 also diverges the light beam 1720 according to the first optical power P1 of the L1 / HWP1 1704.

[0269] The beam 1724 with RHCP is then incident on HWP3 1712A which is in the activated state. Since HWP3 1712A is activated, the beam 1724 with RHCP is transmitted through HWP3 1712A without being substantially affected in terms of polarization or lens effect, and will be incident on H2 / HWP2 1708 as beam 1728A with RHCP. As described above, when configured as a user-side adaptive lens assembly (e.g., Fig.101704 ), L2 / HWP2 1708 is configured similarly to L1 / HWP1 1704 in the illustrated embodiment, i.e., transforming polarization and diverging light with LHCP while converging light with RHCP. Thus, light beam 1728A with RHCP is transformed back to light beam 1732 with LHCP. Thus, when HWP3 1712A is activated, L1 / HWP1 1704 and L2 / HWP2 1704 transmit light beams with opposite polarizations, so that L1 / HWP1 1704 and L2 / HWP2 1708 have opposite lens effects on light passing therethrough. That is, since the light beam 1728A incident on the L2 / HWP2 1704 has the RHCP, the light beam 1732A emitted from the L2 / HWP2 1708 is converged according to the second optical power P2, which is different from the light beam 1724 emitted from the L1 / HWP1 1704, which is divergent according to the first optical power P1. Thereafter, when emitted from the adaptive lens assembly 1700A in the activated state, the light beam 1732A can be seen by the eye.

[0270] In some embodiments, when HWP3 1712A is activated, the first optical power P1 of L1 / HWP1 1704 (which may be negative, i.e., divergent) and the second optical power P2 of L2 / HWP2 1708 (which may be positive, i.e., convergent) may have substantially the same or matching magnitudes. In these embodiments, due to the compensation of the lens effects of L1 / HWP1 1704 and L2 / HWP2 1708, the net optical power Pnet of the adaptive lens assembly 1700A (which may be approximately -P1+P2) may be substantially zero. However, embodiments are not limited thereto, and the first and second optical powers P1, P2 may have different magnitudes, such that the net optical power Pnet may have a non-zero value. For example, in some embodiments, the non-zero Pnet may be equal to the eyeglass prescription of the user, thereby allowing correction of focusing errors (e.g., refractive focusing errors) of the user's eyes.

[0271] It should be understood that although in the illustrated embodiment, the incident beam 1720 has an LHCP, similar results will occur when the incident beam 1720 has an RHCP. That is, when the beam 1720 has an RHCP, the beams 1724 and 1728A have an LHCP, and unlike the illustrated embodiment, the beams 1724 and 1728A converge with respect to the beam 1720. Likewise, the L2 / HWP2 1708 diverges the beam 1728A converged by the L1 / HWP1 1704, so that the net optical power Pnet can be substantially zero.

[0272] It should be understood that the lens effect of L1 / HWP1 1704 and L2 / HWP2 1708 and the above Fig. 17BThe selectivity of the lens effect of the polarization state of the incident light beam described is only an example, and other configurations are possible. Fig. 17B In the embodiment, L1 / HWP1 1704 and L2 / HWP2 1708 are configured to diverge light having LHCP while converging light having RHCP, but in other embodiments, L1 / HWP1 1704 and L2 / HWP2 1708 may be configured to converge light having LHCP while diverging light having RHCP.

[0273] In summary, in some embodiments, when HWP3 1712A of adaptive lens assembly 1700A is in an activated state, due to the compensation of the lens effect between P1 of L1 / HWP1 1704 and P2 of L2 / HWP2 1708, the outgoing light beam 1732A has the same HCP as the incident light beam 1720 and substantially matches the incident light beam 1720 in terms of the lens effect. Therefore, when the user is not viewing virtual content, the world view is relatively unaffected by the adaptive lens assembly ( Fig.10 , 11A , 1004, 1008 in 11B).

[0274] Fig. 17C FIG. 1 shows an example of a switchable wave plate operating with the switchable wave plate deactivated according to some embodiments. Fig.17A 1700B. When the switchable wave plate 1712B is deactivated, for example, when the switch circuit 1716 applies a current or voltage to the switchable wave plate 1712B, the adaptive lens assembly 1700B can be deactivated. The adaptive lens assembly 1700B can correspond to, for example, the first adaptive lens assembly 1004 (located on the world side) or the second adaptive lens assembly 1008 (located on the user side). Hereinafter, as an example, the adaptive lens assembly 1700B will first be described as being configured as the second adaptive lens assembly 1008 on the user side, as a display device (e.g., a display device) that outputs a virtual image to a user. Fig.11A Next, the adaptive lens assembly 1700B will be described as being configured as a first adaptive lens assembly 1004 on the world side, as a display device 1100B ( Fig. 11B ) to reduce or substantially eliminate distortion of the real-world view caused by the lens effect of the second adaptive lens assembly 1008.

[0275] When configured as the second adaptive lens assembly 1008 on the user side ( Fig.11A), each of L1 / HWP1 1704 and L2 / HWP2 1708 can be configured to diverge light having one HCP (e.g., LHCP) passing therethrough. Each of L1 / HWP1 1704 and L2 / HWP2 1708 can also be configured to converge light having another HCP (e.g., RHCP) passing therethrough.

[0276] As mentioned above Fig.11A As described above, some of the light propagating in the x-direction within the waveguide assembly 1012, for example by total internal reflection, can be redirected or coupled out in the z-direction. Fig.11A ) The light coupled out of the switchable lens assembly 1700B may be incident on the switchable lens assembly 1700B as a circularly polarized light beam 1720 having an LHCP. The light beam 1720 travels, for example, along the positive z-direction until the light beam 1720 impinges on the L1 / HWP 1704 to be transmitted therethrough. The L1 / HWP1 1704 transforms the light beam 1720 having the LHCP into a light beam 1724 having an RHCP. Since the L1 / HWP1 1704 is configured to diverge the light having the LHCP, the light beam 1724 also diverges according to the first optical power P1 of the L1 / HWP1 1704.

[0277] The beam 1724 with RHCP is then incident on HWP3 1712B which is in the deactivated state. Fig. 17B Unlike the activated HWP 1712A shown, since HWP3 1712B is deactivated, the beam 1724 having RHCP transmitted through HWP3 1712B is transformed into a beam 1728B having LCHP. Subsequently, the beam 1728B having LHCP is incident on L2 / HWP2 1708. Fig. 17B Unlike the beam 1728A shown, the beam 1728B incident on the L2 / HWP2 1708 has an LHCP, so the L2 / HWP2 1708 further diverges the beam 1728B into a beam 1732B having an RHCP according to the second optical power P2. Fig. 17B Unlike the activation state of HWP 1712A shown, since HWP 1712B is deactivated, L1 / HWP1 1704 and L2 / HWP1 1704 are configured to transmit light beams having the same polarization LHCP. Fig. 17B The compensation effects shown are different for L1 / HWP1 1704 and L2 / HWP2 1708. Fig. 17CL1 / HWP1 1704 and L2 / HWP2 1708 in the embodiment have a superimposed lens effect on the light passing therethrough. That is, since both the light beam 1720 incident on L1 / HWP1 and the light beam 1728B incident on L2 / HWP2 1704 have LHCP, the light beam 1732B emitted from L2 / HWP2 1708 is further diverged in addition to being diverged by L1 / HWP1 1704. Thereafter, when emitted from the adaptive lens assembly 1700B in the deactivated state, the light beam 1732A can be seen by the eye.

[0278] In some embodiments, both the first power P1 of L1 / HWP1 1704 and the second power P2 of L2 / HWP2 1708 may be negative (i.e., divergent) and may have substantially the same or matching magnitudes. In these embodiments, the net power Pnet (which may be approximated as P1+P2) of the adaptive lens assembly 1700B may be substantially twice that of P1 or P2 due to the combined superposition lens effect of L1 / HWP1 1704 and L2 / HWP2 1708. However, embodiments are not limited thereto, and the first and second powers P1, P2 may have different magnitudes.

[0279] It should be understood that although in the illustrated embodiment, the incident light beam 1720 has a LHCP, a parallel result will be produced when the incident light beam 1720 has a RHCP. That is, when the light beam 1720 has a RHCP, unlike the illustrated embodiment, the resulting light beam 1732B has a LHCP and is converged by L1 / HWP1 1704 and L2 / HWP2 1708 according to a net optical power Pnet, the magnitude of which is approximately equal to the sum of the magnitudes of the first and second optical powers P1 and P2.

[0280] It should be understood that the lens effects of L1 / HWP1 1704 and L2 / HWP2 1708 and the effects of these lens effects on the above Fig. 17C The described dependence on the polarization state of the incident light beam is only an example, and other configurations are possible. Fig. 17B In the embodiment, L1 / HWP1 1704 and L2 / HWP2 1708 are configured to diverge light having LHCP while converging light having RHCP, but in other embodiments, L1 / HWP1 1704 and L2 / HWP2 1708 may be conversely configured to diverge light having LHCP while converging light having RHCP.

[0281] Thus, in some embodiments, when the switchable half-wave plate 1712B of the adaptive lens assembly 1700B is in a deactivated state, the outgoing light beam 1732B has an opposite HCP to the incident light beam 1720 and may diverge according to the superimposed optical power P1 of L1 / HWP1 1704 and the optical power P2 of L2 / HWP2 1708. Thus, when the user views virtual content, the virtual content is focused into the eye 210 according to a net optical power having a value of approximately Pnet=P1+P2.

[0282] In the above, it has been described that the Fig.11A The second adaptive lens assembly 1008 on the user side of the display device 1100A is described as being in a deactivated state of the adaptive lens assembly 1700B. However, as described above with respect to Fig. 11B As described above, activating the second adaptive lens assembly 1008 to display virtual content to the user's eye 210 without any compensating effect may result in an undesirable defocus or distortion of the real world view. Therefore, it is desirable to configure the first adaptive lens assembly 1004 on the world side to at least partially compensate or cancel the lens effect of the second adaptive lens assembly 1008 when it is deactivated to display virtual content.

[0283] Return to reference Fig. 17C , when configured to offset the second adaptive lens assembly 1008 ( Fig. 11B ) of the first adaptive lens assembly 1004 on the world side of the lens effect Fig. 11B ), the components of the adaptive lens assembly 1700B may be arranged similarly to those described above with respect to Fig. 11B That is, when light transmitted from the world 510 to the eye 210 passes through the first and second adaptive lens assemblies 1004, 1008, the adaptive lens assembly 1700B (with respect to FIG. Fig. 17C Each of the first and second adaptive lens assemblies 1004, 1008 is configured in the manner described above. In operation, as described above, the polarization of light transmitted from the world through the first adaptive lens assembly 1004 is transformed from a first polarization state to a second polarization state, for example, from RHCP to LHCP. Subsequently, the polarization of light transmitted through the second adaptive lens assembly 1008 is transformed from the second polarization state back to the first polarization state, for example, from LHCP to RHCP. In addition, as described above with respect to Fig. 11BAs described, light transmitted from the world through the first adaptive lens assembly 1004 experiences a first lens effect (e.g., a converging effect) according to a first net optical power Pnet1=P1+P2 having a first sign (e.g., a positive sign). Subsequently, light transmitted through the second adaptive lens assembly 1008 experiences a second lens effect (e.g., a diverging effect) opposite to the first lens effect according to a second net optical power Pnet2=P1'+P2' having a second sign (e.g., a negative sign), because the light incident on the second adaptive lens assembly 1008 has a polarization opposite to that of the light incident on the first adaptive lens assembly 1004. When Pnet1 and Pnet2 have substantially similar sizes, the total lens effect approximated by P=Pnet1+Pnet2 can be substantially zero. Therefore, when the user views virtual content and views real objects in the surrounding world by activating the second lens assembly 1008, the world view is relatively unaffected by the compensation effect of the first lens assembly 1004.

[0284] In various embodiments, when deactivated, each of the first and second adaptive lens assemblies 1004, 1008 can provide a net optical power (positive or negative) within a range of approximately between ±5.0 Diopters and 0 Diopters, between ±4.0 Diopters and 0 Diopters, between ±3.0 Diopters and 0 Diopters, between ±2.0 Diopters and 0 Diopters, between ±1.0 Diopters and 0 Diopters, including any ranges bounded by these values, such as ±1.5 Diopters.

[0285] Display device including an adaptive lens assembly having a switchable half-wave plate and a wave plate lens

[0286] In the following, an adaptive lens assembly including a wave plate lens and a switchable wave plate is described according to some embodiments (e.g., Figures 17A to 17C The display device of the adaptive lens assembly 1300 described above Fig.10 , 11A 11B and 11B) are examples of display devices. The switchable wave plate can be, for example, Figures 13A to 13F , Figures 14A to 14C and Figures 15A to 15B One of the broadband switchable wave plates described.

[0287] Fig.18A and 18B Exemplary display devices 1800A / 1800B are shown, each including a waveguide assembly 1012 between a first broadband adaptive waveplate lens assembly 1004 and a second broadband adaptive waveplate lens assembly 1008. Display device 1800A is similar to the display device 1800A described above with respect to FIG. Fig.11A / 11B describes a display device 1100A / 1100B, wherein each of the first and second adaptive lens assemblies 1004, 1008 includes: a first wave plate lens (L1 / HWP1) 1704, for example, a first half-wave plate lens; a second wave plate lens (L2 / HWP2) 1708, for example, a second half-wave plate lens; and a switchable wave plate (HWP3) 1712, for example, a switchable half-wave plate.

[0288] refer to Fig.18A , described in the above Fig.17A The display device 1800A is described as operating with both the first and second adaptive lens assemblies 1004, 1008 activated. When the switchable wave plate 1712 ( Fig.17A ) is activated, for example, when no current or voltage is applied to the switchable wave plate 1712 by the switch circuit 1816, 1816', the first and second adaptive lens assemblies 1004, 1008 can be activated. As configured, the display device 1800A can be configured to display a real world view to a user, for example, without displaying a virtual image. For example, the display device 1800A can be configured to be used as ordinary glasses or ordinary goggles, such as with respect to Fig. 17B Described in detail. Similar to Fig.17A Each of the first and second adaptive lens assemblies 1004, 1008 includes: a first wave plate lens (L1 / HWP1) 1804, such as a first half-wave plate lens; a second wave plate lens (L2 / HWP2) 1808, such as a second half-wave plate lens; and a switchable wave plate (HWP3) 1812, such as a switchable half-wave plate. Fig.17A As described above, each of L1 / HWP1 1804 and L2 / HWP2 1808 may be configured to have a first lens effect (e.g., a diverging effect) on light having a first HCP (e.g., LHCP) passing therethrough. In addition, each of L1 / HWP1 1804 and L2 / HWP2 1808 may also be configured to have a second lens effect (e.g., a converging effect) opposite to the first lens effect on light having an opposite HCP (e.g., RHCP) passing therethrough. When deactivated (e.g., electrically deactivated using a voltage or current signal provided by switch circuits 1816, 1816'), HWP3 1712B ( Fig. 17C ) is used as a wave plate, such as a half-wave plate. Fig. 17C As described above, when deactivated, HWP31712B ( Fig. 17C) is used as a half-wave plate, which is configured to transform light having LHCP or RHCP passing therethrough into light having RHCP or LHCP, respectively. On the other hand, when activated (e.g., electrically activated (e.g., by removing the voltage or current signal) using a voltage or current signal provided by the switching circuit 1816, 1816'), the HWP3 1712A ( Fig. 17B ) is used as a light transmission medium that does not affect polarization. Fig.17A and 17B A detailed operation principle of the first and second adaptive lens assemblies 1004, 1008 including L1 / HWP1 1804, L2 / HWP2 1808 and HWP3 1812A is provided and is omitted here.

[0289] Based on about Fig. 17B and 17C Detailed description of the operating principle, when the first and second adaptive lens assemblies 1004, 1008 are in an activated state, the light beams (e.g., Fig. 17B 1732A) has a light beam incident thereon (e.g., Fig. 17B In addition, as mentioned above, Fig. 13B As described above, due to the compensation of the net optical power of the first and second lens assemblies 1004 and 1008, the incident light beam 1720 and the outgoing light beam 1732A are substantially matched in terms of the size of the lens optical power.

[0290] Fig.18B FIG. 1 shows an example of a switchable wave plate operating with the switchable wave plate deactivated according to some embodiments. Fig.18A The first and second adaptive lens assemblies 1004, 1008 activate the corresponding switchable wave plates 1712 ( Fig.17A ), for example, by applying a current or voltage to the switchable wave plate 1712 using the switching circuits 1816, 1816'. Hereinafter, the operation of the display device 1800B is described, which outputs a virtual image to a user while also transmitting light from objects in the real world in a manner that reduces or substantially eliminates distortion caused by the lens effect of the adaptive lens assemblies 1004, 1008.

[0291] When displaying a virtual image, as described above Fig.11A and Fig. 17C As described above, some of the light propagating in the waveguide within the waveguide assembly 1012 along the x-direction can be redirected or coupled out in the z-direction. The light beam 1720 travels, for example, along the positive z-direction until the light beam 1720 impinges on the L1 / HWP 1804 of the second adaptive lens assembly 1008. Fig. 17CThe operating principle of the second adaptive lens assembly 1008 described above is that when the second adaptive lens assembly 1008 is in a deactivated state, the outgoing light beam (eg, Fig. 17C 1732B) has a similar structure to the incident beam (e.g., Fig. 17C 1720) in the opposite HCP and diverges according to the second net optical focal length Pnet2 to display virtual content at the corresponding virtual depth plane.

[0292] In various embodiments, when deactivated, each of the first and second adaptive lens assemblies 1004, 1008 can provide a net optical power (positive or negative) within a range between approximately ±5.0 diopters and 0 diopters, between ±4.0 diopters and 0 diopters, between ±3.0 diopters and 0 diopters, between ±2.0 diopters and 0 diopters, between ±1.0 diopters and 0 diopters (including any range bounded by these values, such as ±1.5 diopters). In some embodiments, the first adaptive lens assembly 1004 located between the waveguide assembly 1012 and the world can have a positive optical power, while the second adaptive lens assembly 1008 located between the waveguide assembly 1012 and the user can have a negative optical power, so that the optical powers of the first and second switchable assemblies 1004, 1008 compensate for each other when viewing the world.

[0293] Therefore, still refer to Fig.18A and 18B , the display device 1800A / 1800B includes a pair of adaptive lens assemblies 1004, 1008 located in the optical path between the world 510 and the eye 210, wherein each of the pair of adaptive lens assemblies 1004, 1008 includes a switchable wave plate (e.g., Fig.17A / 1712A / 1712B in 1712A / 1712B) are configured to change the polarization state of light passing therethrough when electrically deactivated. When electrically deactivated, the pair of adaptive lens assemblies have net optical powers (Pnet1, Pnet2) of opposite signs, such that light passing through the pair of adaptive lens assemblies converges or diverges according to a combined optical power, the magnitude of which is approximately the difference in magnitude of the optical powers of the pair of adaptive lens assemblies. The user can view virtual content at a depth plane according to Pnet2 (which can be negative), while the view of the world is relatively unaffected by Pnet2, which is at least partially compensated by Pnet1 (which can be positive).

[0294] In some embodiments, each of the pair of adaptive lens components has a corresponding net optical power (Pnet1, Pnet2), which can be electrically adjusted or modulated to one of a plurality of values ​​using switch circuits 1816, 1816'. As described above, when the image of the virtual object generated by the light coupled out of the waveguide component 1012 moves in 3D, the second net optical power (Pnet2) of the second adaptive lens component 1008 on the user side is adjusted to adapt to the changing depth of the virtual depth plane. At the same time, according to an embodiment, the first net optical power (Pnet1) of the first adaptive lens component 1004 is adjusted accordingly using switch circuits 1816, 1816' so that the real world view does not suffer from undesirable defocus or distortion. To meet this and other needs, in some embodiments, the display device 1800A / 1800B includes a controller 1804 configured such that when a first net optical power (Pnet1) of a first adaptive lens assembly in the pair of adaptive lens assemblies 1004, 1008 is electrically adjusted, a second optical power (Pnet2) of a second adaptive lens assembly in the pair of adaptive lens assemblies is correspondingly adjusted such that the combined optical power (Pnet1+Pnet2) remains approximately constant (e.g., approximately zero). The controller circuitry and the switchable wave plate 1812 are configured such that the time to switch the first and second net optical powers Pnet, Pnet2 so as to adjust the virtual depth plane using the second adaptive lens assembly 1008 as described herein and to compensate the real-world view using the first adaptive lens assembly 1004 is less than about 100 milliseconds, less than about 50 milliseconds, less than about less than about 10 milliseconds, less than about 5 milliseconds, less than about 1 millisecond, or a value within a range defined by any of these values.

[0295] Broadband switchable waveplate lens

[0296] As described above, according to various embodiments, a broadband adaptive wave plate lens assembly can generate images at multiple depth planes by selectively switching between multiple states with different optical powers. In some of the above embodiments, the broadband adaptive wave plate lens assembly can generate images at multiple depth planes by selectively switching between multiple states with different optical powers. Fig. 12A 1158) coupled to one or more broadband passive wave plate lenses (e.g., Fig. 12A In some other embodiments, a broadband switchable wave plate lens (e.g., Fig. 12B 1154B in the embodiment) to realize the broadband capability of the broadband adaptive wave plate lens assembly. In the following, the structure and configuration of the liquid crystal layer of the broadband switchable wave plate lens and the broadband adaptive lens assembly with the broadband switchable wave plate lens according to the embodiment are described.

[0297] Fig.19A1900 is a plan view of a broadband wave plate lens 1900 including a LC molecule layer formed on a transparent substrate according to various embodiments. Fig.19A The arrow pattern shown is used to assign the elongation direction of the bottommost LC molecules or the LC molecules closest to the substrate, and / or the spatial distribution of the local directors of the LC molecules resulting therefrom. In the embodiment shown, the LC molecules closest to the substrate at a given radius relative to the central region have substantially the same elongation direction.

[0298] In some embodiments, the wave plate lens 1900 is a polarization type Fresnel Zone Plate (FZP) lens having a radially symmetric and radially modulated birefringence distribution. In some embodiments, the elongation direction orientation or local director of the LC molecules can vary with radius according to a mathematical function. In the illustrated embodiment, the azimuth angle φ of the local director of the LC molecules can have discrete values ​​in different zones arranged at different radii relative to the center of the wave plate lens 1900. For example, φ in the mth zone can be expressed as

[0299]

[0300] Where f is the focal length and r is the distance from the center of the wave plate lens 1900.

[0301] In some other embodiments, the spatial distribution of the elongation directions or local directors of the LC molecules or the resulting local birefringence is similar to that described above with respect to Fig.16A and 16B The situation described.

[0302] In some embodiments, the local orientation direction (e.g., the elongation direction) of the LC molecules above the bottommost LC molecules may be substantially the same as the local orientation direction of the bottommost LC molecules closest to the substrate. In some other embodiments, the local orientation direction of the LC molecules above the bottommost LC molecules may be substantially different from the local orientation direction of the bottommost LC molecules closest to the substrate. For example, the local orientation direction of the LC molecules above the bottommost LC molecules may be continuously twisted, as described below (e.g., Fig. 20A , 20B ).

[0303] In operation, the Fig.16A and 16B In a manner similar to the wave plate lens described above, the broadband wave plate lens 1900 has a polarization selective lens action, acting as a convex (or positive) lens ( Fig.19B ), for incident light 1162B having a first polarization (e.g., right-handed circular polarization (RHCP)), and also acts as a concave (or negative) lens ( Fig.19C) for an incident light beam 1162A having a second polarization (e.g., left-handed circular polarization (LHCP)). In addition, the broadband wave plate lens 1900 flips the polarization of the diffracted light. That is, Fig.19B As shown, incident light 1162B having RHCP is transformed into light 1166A having LHCP by broadband wave plate lens 1900, and as shown in FIG. Fig.19C As shown, incident light 1162A having LCHP is transformed into light 1166B having RHCP by wave plate lens 1900. As described above, the relative proportion of undiffracted leakage light 1904 determines the diffraction efficiency.

[0304] The inventors have found that by specifically configuring the twisted arrangement of LC molecules vertically within one or more LC layers (e.g. Fig. 20A , 20B ), or by using negative dispersion LC materials ( Fig.21 ), the high bandwidth capability of the wave plate lens can be further improved to further reduce undiffracted light leakage 1904 and improve diffraction efficiency, thereby further reducing unwanted visual effects (such as ghost images), as described below.

[0305] Fig. 20A and 20B A plan view and a cross-sectional view of a broadband wave plate lens 2000 including a plurality of LC layers according to an embodiment are schematically shown, respectively. The broadband wave plate lens 2000 shown includes a stack of two LC layers 2004, 2008 having LC molecules with opposite twist senses, such that light delay caused by one of the LC layers 2004, 2008 is compensated by the other of the LC layers 2004, 2008. For illustrative purposes only, Fig. 20A and 20B The relative orientation of the LC molecules is shown schematically varying laterally in a particular manner. However, it should be understood that the lateral arrangement of the LC molecules across the xy plane at a given depth in the z direction may have any of the various arrangements described above, including those described above with respect to Fig.16A and 16B and about Fig.19A For example, in some embodiments, the Fig.19A In a similar manner, the LC molecules closest to the substrate have approximately the same local orientation direction (e.g., local elongation direction or local director) at a given radius relative to the central region, and / or have an orientation direction that varies with radius. In addition, the arrangement of LC molecules in a given columnar region in the two LC layers 2004, 2008 can be represented as having a nematic director n that varies with vertical position within the LC layer according to the following formula:

[0306]

[0307] where φ is the azimuth angle of the director n in the xz plane. That is, for a given column of LC molecules having a first twist direction in one of the LC layers 2004, 2008, the corresponding column of LC molecules in the other of the LC layers 2004, 2008 has an opposite twist direction. In other words, the LC molecules in the two LC layers 2004, 2008 have mirror images of each other with respect to the interface between the two LC layers 2004, 2008.

[0308] According to an embodiment, reactive mesogens may be used to create LC molecule arrangements in the two LC layers 2004, 2008. For example, by appropriately configuring the alignment layer 1302-0 on the substrate 1312, the bottommost LC molecules in the first LC layer 2004 closest to the alignment layer 1302-0 may be arranged to have a first azimuth angle.

[0309] The first azimuth angle can be determined, for example, according to the above Fig.16A , 16B 19A. In addition, by adding a chiral agent to the first LC layer 2004, the LC molecules above the bottommost LC molecules in the first LC layer 2004 may be configured to have a first twist, so that the topmost LC molecules closest to the surface of the first LC layer 2004 have a second azimuth. Thereafter, by appropriately configuring the surface area of ​​the first LC layer 2004, the bottommost LC molecules in the second LC layer 2008 closest to the first LC layer 2004 may be arranged to have a second azimuth. In addition, by adding a chiral agent to the second LC layer 2008, the LC molecules above the bottommost LC molecules in the second LC layer 2008 may be configured to have a second chiral twist, so that the topmost LC molecules closest to the surface of the second LC layer 2008 have a third azimuth. In some embodiments, the first and second chiral twists are substantially the same, so that the bottommost LC molecules of the first LC layer 2004 and the topmost LC molecules of the second LC layer 2008 have the same first azimuth.

[0310] In one example configuration, by configuring the LC layers 2004, 2008 to have a suitable thickness, for example between about 1 μm and 2 μm or between about 1.5 μm and 2 μm (e.g., about 1.7 μm), and a suitable chiral twist between about 50 degrees and 90 degrees or between about 60 degrees and 80 degrees (e.g., about 70 degrees), a relative width Δλ / λ0 greater than 40%, 50% or 60% (e.g., about 56%) can be achieved, and according to an embodiment, the diffraction efficiency is greater than 99% in this wavelength range.

[0311] As mentioned above, the diffraction efficiency (η) can be expressed as η = sin 2(πΔnd / λ), where Δn is the birefringence, λ is the wavelength, and d is the thickness. Typically, an optically anisotropic material shows a Δn that decreases as λ increases (referred to herein as positive dispersion of Δn). However, positive dispersion of Δn results in different phase retardations Γ=2πΔnd / λ at different λ. The inventors have recognized that by employing an optically anisotropic material that shows a Δn that increases as λ increases (referred to herein as having negative dispersion of Δn), the phase retardation Γ can be kept relatively constant at different λ, and according to an embodiment, the diffraction efficiency η can be kept relatively high and constant over a relatively wide wavelength range.

[0312] Fig.21 1 shows a cross-sectional view of a broadband wave plate lens 2100 according to an embodiment, which includes a negative dispersion (ND) liquid crystal (LC) layer 2104 and an alignment layer 1312-0 formed on a substrate 1312. Fig.19A and Fig. 20A In order to provide a lens effect, the broadband wave plate lens described in / 20B can arrange the ND LC layer 2104 by appropriately arranging the alignment layer 1312-0, so that the wave plate lens 2100 has a birefringence (Δn) that varies in the radial direction starting from the central area. In addition, in some embodiments, the above-mentioned Fig.16A , 16B In a manner similar to that described in 19A, for example, using an alignment layer 1312-0 configured in a manner discussed elsewhere in this specification, the bottommost LC molecules closest to the substrate 1312 can be arranged to have approximately the same orientation direction at a given radius relative to the center region, as well as to have an orientation direction that varies approximately with radius.

[0313] In various embodiments, the negative dispersion (ND) liquid crystal (LC) layer 2104 may have an average, local, mean, median, maximum, or minimum value of the birefringence (Δn) of 0.05 to 0.10, 0.15 to 0.20, 0.20 to 0.25, 0.25 to 0.30, 0.30 to 0.35, 0.35 to 0.40, 0.40 to 0.45, 0.45 to 0.50, 0.50 to 0.55, 0.55 to 0.60, 0.60 to 0.65, 0.65 to 0.70, or a value within a range defined by any of these values. In addition, the negative dispersion (ND) liquid crystal (LC) layer 2104 may have the following intra-layer birefringence (Δn) range: 0.01 to 0.05, 0.05 to 0.10, 0.15 to 0.20, 0.20 to 0.25, 0.25 to 0.30, 0.30 to 0.35, 0.35 to 0.40, or a value within a range bounded by any of these values.

[0314] Still reference Fig.21, and the above Fig. 20A and 20B Unlike the LC molecules described above, the ND LC layer 2104 may be vertically homogenous. For example, in the ND LC layer 2104, the LC crystals formed above the bottommost LC molecules may not be twisted. Alternatively, in some embodiments, within a given columnar region, the local director n may be substantially constant throughout the thickness of the ND LC layer 2104. In some other embodiments, within a given columnar region, the local director n may be substantially random throughout the thickness of the LC layer 2104.

[0315] According to various embodiments, the ND LC layer 2104 may be formed of a material (e.g., a reactive liquid crystal element) having material properties such that Δn increases with increasing wavelength (λ) within at least a portion of a visible spectrum within 400 to 800 nm, wherein at least a portion of the visible spectrum includes one or more of a red spectrum including wavelengths within a range of about 620 to 780 nm, a green spectrum including wavelengths within a range of about 492 to 577 nm, and a blue spectrum within a range of about 435 to 493 nm, or a spectrum within a wavelength range defined by any wavelength within the visible spectrum within about 400 to 800 nm (e.g., 400 to 700 nm, 430 to 650 nm, or 450 to 630 nm). In some embodiments, the NC LC layer 2104 has an anomalous refractive index n within any of these wavelength ranges. e The dispersion is smaller than the ordinary refractive index n o of dispersion.

[0316] In some embodiments, the ND LC layer 2104 includes a smectic liquid crystal (LC), such as a smectic LC-polymer composite material.

[0317] Advantageously, in some embodiments, the broadband waveplate lens 2100 includes a single ND LC layer 2104 having a birefringence index different from, for example, that described above with respect to Fig. 20A and 20B A broadband waveplate lens 2000 having multiple layers is described.

[0318] According to the embodiment, in the above Fig.16A , 16B In various embodiments of the broadband wave plate lens described in any of 19A, 20A / 20B and 21, the LC layer can be configured to be passive or switchable. When configured as a passive lens, the LC molecule layer can be formed of polymerized LC (LCP), and when configured as a switchable lens, the LC molecule layer can be formed of unpolymerized LC molecules or reactive liquid crystal elements. In a manner similar to that described above with respect to the various embodiments above, when configured as a switchable lens, the above with respect to Fig.16A, 16B , 19A, 20A / 20B and 21 described wave plate lenses further include a layer located on both sides of the LC molecule layer (e.g., Fig. 14C ) or the same side (e.g. Fig.15A / 15B) transparent electrode.

[0319] Figures 22A to 22C The switchable broadband wave plate lens 2200 is shown in operation, which can be similar to the above with respect to Fig.16A , 16B Any broadband wave plate lens described in any of 19A, 20A / 20B and 21. Fig.22A , 22B and 22C respectively show a deactivated switchable broadband wave plate lens 2200 with an LHCP beam incident thereon, a deactivated switchable broadband wave plate lens 2200 with an RHCP beam incident thereon, and an activated switchable broadband wave plate lens 2200 with an LHCP beam 1162A or a RHCP beam 1162B incident thereon.

[0320] refer to Fig.22A , the switchable broadband wave plate lens 2200 includes as described above Fig.16A , 16B , 19A, 20A / 20B and 21, and is configured to selectively switch between different lens states by electrically activating and deactivating. According to various embodiments, in operation, the switchable broadband wave plate lens 2200 is configured to diverge light according to an optical power -P depending on the polarization (e.g., circular polarization) of the incident light 1162A, 1162B, and to converge light according to an optical power P depending on the polarization (e.g., circular polarization) of the incident light 1162A, 1162B.

[0321] refer to Fig.22A , when deactivated, the switchable broadband wave plate lens 2200 is configured to diverge the LHCP beam 1162A incident thereon into a RHCP beam 1166B according to the optical power -P. Fig. 22B , when deactivated (e.g., electrically deactivated), the switchable broadband wave plate lens 2200 is configured to converge the RHCP beam 1162B incident thereon into the LHCP beam 1166A according to the optical power P. On the other hand, referring to Fig. 22C , when activated (e.g., electrically activated), the polarization of the circularly polarized light passing therethrough is maintained (not shown), and the RHCP beam 1162B and the LHCP beam 1162A incident thereon pass through the switchable broadband waveplate lens 2200 without being substantially converged or diverged (i.e., optical power P~0).

[0322] Broadband adaptive wave plate lens assembly with switchable wave plate lens

[0323] As mentioned above Figures 22A to 22C As described, the switchable broadband wave plate lens according to the embodiment can be configured so that when deactivated, it can apply an optical power P or -P depending on the polarization of the incident light, and when activated, it substantially does not apply an optical power. The inventors have recognized that by combining two or more switchable broadband wave plate lenses, more lens states can be obtained to display virtual images at many different focal depths. In the following, a broadband adaptive lens assembly including a plurality of switchable broadband wave plate lenses is described, wherein by configuring the broadband wave plate lenses to have different optical powers, 2 lens states can be obtained for incident light with a given polarization. n different optical power states.

[0324] Figures 23A to 23D A broadband adaptive lens assembly 2300 is shown, which includes a first switchable broadband wave plate lens 2204 and a second switchable broadband wave plate lens 2208, each of which can be used in the same manner as described above with respect to Figures 22A to 22C Each of the switchable broadband waveplate lenses 2204, 2208 can be operated in a similar manner to the switchable broadband waveplate lenses described above. Fig.16A , 16B , 19A, 20A / 20B and any of the broadband wave plate lenses described in 21 are arranged in a similar manner. Fig.23A , 23B , 23C and 23D show state combinations in which the first switchable broadband wave plate lens 2304 / the second switchable broadband wave plate lens 2308 are deactivated / deactivated, deactivated / activated, activated / deactivated, and activated / activated, respectively.

[0325] In the illustrated embodiment, the first switchable broadband wave plate lens 2304 is configured to be similar to the above Figures 22A to 22C The first switchable broadband wave plate lens 2304 is configured in a similar manner to the broadband wave plate lens 2200 described above. That is, when deactivated, the first switchable broadband wave plate lens 2304 is configured to diverge the LHCP light beam 1162A incident thereon into the RHCP light beam 1166B according to the optical focal length -P1. In addition, although not shown, when deactivated, the first switchable broadband wave plate lens 2304 is configured to converge the RHCP light beam incident thereon into the LHCP light beam according to the optical focal length +P1. On the other hand, when activated, the first switchable broadband wave plate lens 2304 is configured to substantially maintain the polarization of the circularly polarized light passing therethrough without substantially converging or diverging the light (i.e., the optical focal length P1 to 0).

[0326] On the other hand, when deactivated, the second switchable broadband waveplate lens 2308 is configured to have the same sign as described above with respect to the sign of the applied optical power. Figures 22A to 22C The broadband wave plate lens 2200 described above operates in the opposite manner. That is, when deactivated, the second switchable broadband wave plate lens 2308 is configured to converge the LHCP light beam 1162A incident thereon into the RHCP light beam 1166B according to the optical focal length +P2. In addition, although not shown, when deactivated, the second switchable broadband wave plate lens 2308 is configured to diverge the RHCP light beam incident thereon into the LHCP light beam according to the optical focal length -P2. On the other hand, when activated, the second switchable broadband wave plate lens 2308 is configured to substantially maintain the polarization of the circularly polarized light passing therethrough without substantially converging or diverging the light (i.e., optical focal length P2~0).

[0327] refer to Fig.23A , the first switchable broadband wave plate lens 2304 is deactivated, and the LHCP beam 1162A incident thereon is diverged into the RHCP beam 1166B according to the optical power -P1. Thereafter, the second switchable broadband wave plate lens 2208 is deactivated, and the RHCP beam 1166B incident thereon is diverged into the LHCP beam 1170A according to the optical power -P2. In summary, the LHCP beam 1162A incident on the broadband adaptive lens assembly 2300 is diverged into the LHCP beam 1170A according to the net optical power -(P1+P2).

[0328] refer to Fig. 23B , the first switchable broadband wave plate lens 2304 is deactivated and diverges the LHCP beam 1162A incident thereon into a RHCP beam 1166B according to the optical power -P1. Thereafter, the second switchable broadband wave plate lens 2208 is activated and maintains the polarization of the RHCP beam 1166B passing therethrough without substantially converging or further diverging. In summary, the LHCP beam 1162A incident on the broadband adaptive lens assembly 2300 is diverged into a RHCP beam 1166BA according to the net optical power -P1.

[0329] refer to Fig.23C , the first switchable broadband wave plate lens 2304 is activated and maintains the polarization of the LHCP beam 1162A passing therethrough without substantially converging or diverging. Thereafter, the second switchable broadband wave plate lens 2308 is deactivated and converges the LHCP beam 1162A incident thereon into the RHCP beam 1170B according to the optical power +P2. In summary, the LHCP beam 1162B incident on the broadband adaptive lens assembly 2300 is converged into the RHCP beam 1170B according to the net optical power +P2.

[0330] refer to Fig.23D, both the first and second switchable broadband wave plate lenses 2304, 2308 are activated and maintain the polarization of the LHCP beam 1162A passing therethrough without substantially converging or diverging. Therefore, the LHCP beam 1162B incident on the broadband adaptive lens assembly 2300 appears as the LHCP beam 1162B substantially unaffected.

[0331] In short, if Figures 23A to 23D As shown, according to an embodiment, by selectively switching the first and second switchable broadband wave plate lenses 2304 and 2308, the broadband adaptive lens assembly 2300 can have four different optical power states: 0, -P1, +P2 and -(P1+P2).

[0332] In addition, although not shown, in a similar manner, when the incident light is a RHCP beam, by selectively switching the first and second switchable broadband wave plate lenses 2304 and 2308, the broadband adaptive lens assembly 2300 can have four different optical power states: 0, +P1, -P2 and +(P1+P2).

[0333] Additionally, although not shown, in some embodiments, the second switchable broadband waveplate lens 2308 may be configured to operate in the same manner as the first switchable broadband waveplate lens 2304 with respect to the dependence of the optical power sign on the polarization of the incident light. In these embodiments, for example, when the incident light is an LHCP beam, the four different optical power states obtained will be 0, -P1, -P2, and -(P1-P2).

[0334] In addition, if the second switchable broadband wave plate lens 2308 is configured to operate in the same manner as the first broadband wave plate lens 2304 with respect to the dependence of the optical power sign on the polarization of the incident light, then when the incident light is a RHCP beam, the four different optical power states obtained will be 0, P1, P2 and (P1-P2).

[0335] exist Figures 23A to 23D , the broadband adaptive lens assembly 2300 shown is configured to achieve variable optical power by independently switching the lenses themselves (e.g., the first and second switchable broadband wave plate lenses 2304, 2308). However, other embodiments are also possible: in which one or both of the first and second switchable broadband wave plate lenses 2204, 2208 are replaced by a combination of a passive wave plate lens and a switchable wave plate, similar to the above description of Fig. 12A A combination of a passive wave plate lens 1154A and a switchable wave plate 1158 is described.

[0336] Fig.24A An integrated broadband adaptive lens assembly 2400 according to an embodiment is shown, which includes similar Fig.19A , 20A The integrated broadband adaptive lens assembly 2400 includes a switchable LC layer 2304, which can be similar to the switchable LC layer 2304 described above. Fig.19A , 20A / 20B and 21, except that the switchable LC layer 2304 is between a pair of passive wave plate lens stacks 2308, 2312. Fig.13F In a similar manner, LC molecules are inserted into the gap formed between the surfaces of the passive wave plate lens stacks 2308, 2312 facing each other through the spacer 1350, and the insertion method is described elsewhere in the specification. The first passive wave plate lens stack 2308 includes a substrate 1312 with a lower transparent electrode 1316 formed thereon, followed by an alignment layer 2302 and a lower polymeric LC (LCP) layer 2302-1. Similarly, the second passive wave plate lens stack 2312 includes a substrate 1312 with an upper transparent electrode 1320 formed thereon, followed by an alignment layer 2302 and an upper polymeric LC (LCP) layer 2302-2.

[0337] Each of the first and second passive wave plate lens stacks 2308, 2312 serves as a wave plate lens as well as an alignment layer for aligning the LC molecules in the switchable LC layer 2304. Fig. 13C , 13F In a similar manner, the LC molecules closest to the gap in the lower LCP layer 2302-1 and the LC molecules closest to the gap in the upper LCP layer 2302-2 are arranged so that the outermost LC molecules of the switchable LC layer 2304 are self-aligned. However, the embodiment is not limited thereto, and in some other embodiments, the outermost LC molecules of the switchable LC layer 2204 may be sufficiently aligned by the upper and / or lower alignment layer 2302, thereby omitting one or both of the first and second LCP layers 2302-1, 2302-2.

[0338] refer to Fig.24A In various embodiments throughout the specification, the thickness of the switchable LC layer (e.g., the switchable LC layer 2304 inserted into the gap) is about 1 μm to 50 μm, 1 to 10 μm, 10 to 20 μm, 20 to 30 μm, 30 to 40 μm, 40 to 50 μm, or a value within any range defined by these values. In addition, the thickness of the passive LC layer (e.g., the LCP layers 2302-1, 2302-2) can be about 0.1 μm to 50 μm, 0.1 to 1 μm, 1 to 10 μm, 10 to 20 μm, 20 to 30 μm, 30 to 40 μm, 40 to 50 μm, or a value within any range defined by these values.

[0339] In the illustrated embodiment, the LC molecules of each of the LCP layers 2302-1, 2302-2 may have a net twist angle of 30 to 90 degrees, 40 to 80 degrees, 50 to 70 degrees, or any angle within a range bounded by any of these values, for example, about 60 degrees.

[0340] In some embodiments, the switchable LC layer 2304 may be a single layer, similar to the above description of Fig.21 However, the embodiment is not limited thereto. For example, the switchable LC layer 2204 may be configured as described above with respect to Fig. 20A A similar approach as described in / 20B includes multiple LC layers.

[0341] In operation, this article is about Fig.24A The integrated broadband adaptive lens assembly 2400 described shares similarities to the above Fig.13F Some features of the switchable wave plate 1300F described herein. For example, in both embodiments, the switchable wave plate element ( Fig.13F The switchable TN LC layer 1302 and Fig.24A The switchable LC layer 2304 in the embodiment of FIG. 2 is sandwiched between a pair of passive wave plate elements ( Fig.13F multiple TN LC layers 1302-1, 1302-2 in; polymeric LC (LCP) layers 2302-1, 2302-2). In both embodiments, the switchable wave plate element is configured to change the polarization of light passing therethrough into orthogonal polarized light. Similarly, in both embodiments, the passive wave plate elements are similarly aligned by corresponding alignment layers so that when the switchable wave plate element is electrically activated to allow light to pass therethrough without diffraction, the passive wave plate elements have a canceling effect on each other. On the other hand, when the switchable wave plate element is electrically deactivated to diffract light passing therethrough, the passive wave plate elements have a complementary effect. In a specific embodiment, when the passive wave plate elements have the same optical power, and when the switchable wave plate element is activated, the net optical power of the component is approximately zero, and the polarization of the light does not change. On the other hand, when the switchable wave plate element is deactivated, the net optical power of the component is the net sum of the optical powers of the switchable wave plate element and the passive wave plate element having different signs. In the following, with respect to Figures 24B to 24D , a specific embodiment is described in which the passive wave plate element is a half-wave plate lens and the switchable wave plate element is also a half-wave plate.

[0342] Figures 24B to 24D An integrated broadband adaptive lens assembly 2400 is shown in operation, which may be similar to the above with respect to Figures 17A to 17C An adaptive lens assembly is described, except that the middle switchable half-wave plate is configured as a lens to apply optical power.

[0343] Fig. 24BThe above is shown in terms of optical function. Fig.24A An integrated broadband adaptive lens assembly 2400 is described. Fig.24C Shown in Fig. 24B The integrated broadband adaptive lens assembly 2400A ( Fig.24A ),and Fig.24D Shown in Fig. 24B The switchable component 2400B of the integrated broadband adaptive lens component 2400 is shown as being operated with the switchable wave plate lens 2304 deactivated. The integrated broadband adaptive lens component 2400 is configured to couple and transmit therein the waveguide component 1012 ( Fig.10 , 11A , 11B) outcoupled light. The integrated broadband adaptive lens assembly 2400 includes: a passive wave plate lens stack 2308 ( Fig.24A ) corresponding to the first wave plate lens (L1 / HWP1) 2308 (eg, the first half-wave plate lens); and the passive wave plate lens stack 2312 ( Fig.24A ) corresponding to the second wave plate lens (L2 / HWP2) 2312 (eg, a second half-wave plate lens); and the switchable LC layer 2304 ( Fig.24A ) corresponds to the switchable half-wave plate (L3 / HWP3) 2304.

[0344] exist Figures 24B to 24D In the deactivated state, L3 / HWP 2304B ( Fig.24D ), L1 / HWP1 2308 and L2 / HWP2 2312 are used as passive half-wave plate lenses, which are configured to apply optical powers P3, P1 and P2, respectively, and flip the handedness of circularly polarized light passing therethrough from a first handedness (first HCP) to a second handedness (second HCP). On the other hand, L3 / HWP 2304A ( Fig.24C ) is configured to maintain the handedness of circularly polarized light passing therethrough.

[0345] Additionally, when deactivated (eg, electrically deactivated using a voltage or current signal provided by switch circuit 1716), L3 / HWP3 2304B ( Fig.24D ) is used as a half-wave plate lens with optical power P3. On the other hand, when activated using the switch circuit 1716 (e.g., by removing the voltage or current signal), the L3 / HWP3 2304A ( Fig.24C ) is used as a light transmission medium without affecting polarization or providing any substantial lensing effect.

[0346] Fig.24C2400B is shown operating with L3 / HWP 2304A activated. The integrated broadband adaptive lens assembly 2400B may correspond to the first adaptive lens assembly 1004 ( Fig.10 , located on the world side) or the second adaptive lens assembly 1008 ( Fig.10 , located on the user side). By way of example only, the integrated broadband adaptive lens assembly 2400A will be described as corresponding to the first adaptive lens assembly 1004 or the second adaptive lens assembly 1008 as a display device 1000 ( Fig.10 ). For example, the display device 1000 ( Fig.10 ) can be used as ordinary glasses or ordinary goggles. Each of L1 / HWP1 2308 and L2 / HWP2 2312 can be configured to have a first lens effect (e.g., diverging effect) on light having a first HCP (e.g., LHCP) passing therethrough. Although not shown, each of L1 / HWP1 2308 and L2 / HWP2 2312 can also be configured to have a second lens effect (e.g., converging effect) opposite to the first lens effect on light having an opposite HCP (e.g., RHCP) passing therethrough.

[0347] In the illustrated embodiment, light beam 1720 may represent a light beam from the world that is incident on either the first adaptive lens assembly 1004 (located on the world side) or the second adaptive lens assembly 1008 (located on the user side) while display device 1000 ( Fig.10 ) is used as ordinary glasses or goggles that do not display virtual content. By way of example only, the light beam 1720 having a first HCP (e.g., LHCP) travels, for example, along the positive z-direction until the light beam 1720 passes through the L1 / HWP 2308 to be transmitted therethrough and transformed into a light beam 1724 having a RHCP while diverging the light beam 1720 according to the first optical power -P1.

[0348] Still reference Fig.24C , then, since L3 / HWP3 2304A is activated, the beam 1724 with RHCP is transmitted through L3 / HWP3 2304A, substantially unaffected in terms of polarization or lensing, to be incident on L2 / HWP2 2312 as beam 1728A with RHCP. As described above, when configured as a user-side adaptive lens assembly (e.g., Fig.10 When the second adaptive lens assembly 1004 in FIG. 1 is used, L2 / HWP2 2313 is similar to L1 / HWP1 1704 ( Fig. 17B) is configured, that is, to convert polarization and diverge light with LHCP while converging light with RHCP. Therefore, the light beam 1728A with RHCP is converted back to the light beam 1732A with LHCP. Therefore, when L3 / HWP3 2304A is activated, L1 / HWP1 2308 and L2 / HWP2 2312 transmit light beams with opposite polarizations, so that L1 / HWP1 2308 and L2 / HWP2 2312 have opposite lens effects on the light passing therethrough. That is, since the light beam 1728A incident on L2 / HWP2 2312 has RHCP, the light beam 1732A emitted from L2 / HWP2 2312 converges according to the second optical power +P2, which is different from the light beam 1724 emitted from L1 / HWP1 1704, which diverges according to the first optical power -P1. Thereafter, light beam 1732A may be viewed by the eye when emitted from adaptive lens assembly 1700A in an activated state.

[0349] In some embodiments, when L3 / HWP3 2304A is activated, the first optical power -P1 of L1 / HWP1 2308 and the second optical power +P2 of L2 / HWP2 2312 may have substantially the same or matching magnitudes, while having opposite signs. In these embodiments, the net optical power Pnet (which may be approximated as -P1+P2) of the integrated broadband adaptive lens assembly 2400 may be substantially zero, such that the world view is substantially unaffected for the viewer. However, embodiments are not limited thereto, and the first and second optical powers -P1, +P2 may have different magnitudes, such that the net optical power Pnet may have a non-zero value. For example, in some embodiments, the non-zero Pnet may be equal to the user's eyeglass prescription, thereby allowing correction of focusing errors (e.g., refractive focusing errors) of the user's eyes.

[0350] Although in the illustrated embodiment, the incident light beam 1720 has an LHCP, similar results will be produced when the incident light beam 1720 has an RHCP. That is, when the incident light beam 1720 has an RHCP, the light beams 1724 and 1728A have an LHCP, and unlike the illustrated embodiment, the light beams 1724 and 1728A are converged according to the optical power +P1. Similarly, the light beam 1728A is diverged according to the optical power -P2, so that the net optical power Pnet can be +P1-P2, which can be substantially zero.

[0351] It should be understood that the lens effect of L1 / HWP1 2308 and L2 / HWP2 2312 and the above Fig.24C The described lensing effect selectivity of the polarization state of the incident light beam is only an example, and other configurations are possible. Fig.24CIn the embodiment, L1 / HWP1 2308 and L2 / HWP2 2312 are configured to diverge light having LHCP while converging light having RHCP, but in other embodiments, L1 / HWP1 2308 and L2 / HWP2 2312 may be configured to converge light having LHCP while diverging light having RHCP.

[0352] In summary, in some embodiments, when L3 / HWP3 2304A is activated, the outgoing light beam 1732A has the same HCP as the incoming light beam 1720 and substantially matches the incoming light beam 1720 in terms of lens effect due to compensation of the lens effect between P1 of L1 / HWP1 2308 and P2 of L2 / HWP2 2312. Thus, when the user is not viewing virtual content, the world view is relatively unaffected by the adaptive lens assembly ( Fig.10 , 11A , 1004, 1008 in 11B).

[0353] Fig.24D shows operation with L3 / HWP3 2304B deactivated Fig. 24B The integrated broadband adaptive lens assembly 2400B may correspond to the first adaptive lens assembly 1004 (located on the world side) or the second adaptive lens assembly 1008 (located on the user side). Hereinafter, as an example, the integrated broadband adaptive lens assembly 2400B will first be described as being configured as the second adaptive lens assembly 1008 on the user side, as a display device (e.g., Fig.11A Next, the integrated broadband adaptive lens assembly 2400B will be described as being configured as a first adaptive lens assembly 1004 on the world side, as a display device 1100B ( Fig. 11B ), thereby reducing or substantially eliminating distortion of the real-world view caused by the lens effect of the second adaptive lens assembly 1008.

[0354] When configured as the second adaptive lens assembly 1008 on the user side ( Fig.11A ), each of L1 / HWP1 2308 and L2 / HWP2 2312 can be configured to diverge light having one HCP (e.g., LHCP) passing therethrough. Each of L1 / HWP1 2308 and L2 / HWP2 2312 can also be configured to converge light having another HCP (e.g., RHCP) passing therethrough.

[0355] As mentioned above Fig.11AAs described above, some of the light propagating in the x-direction within the waveguide assembly 1012, for example by total internal reflection, can be redirected or coupled out in the z-direction. Fig.11A ) The light coupled out may be incident on the integrated broadband adaptive lens assembly 2400B as a circularly polarized light beam 1720 having an LHCP. The light beam 1720 travels, for example, along the positive z-direction until the light beam 1720 is transmitted through the L1 / HWP 2308 and is transformed into a light beam 1724 having an RHCP while also being diverged according to the first optical power -P1 of the L1 / HWP1 2308.

[0356] Subsequently, since L3 / HWP3 2304B is deactivated, the light beam 1724 with RHCP transmitted through L3 / HWP3 2304B is transformed into a light beam 1728B with LCHP while also being diverged or converged according to the third optical power - / +P3. Subsequently, the light beam 1728B with LHCP is incident on L2 / HWP2 2312. Fig.24C Unlike the beam 1728A shown, since the beam 1728B incident on the L2 / HWP2 2312 has an LHCP, the L2 / HWP2 2312 further diverges the beam 1728B into a beam 1732B having an RHCP according to the second optical power -P2. Fig.24C The configuration shown is different. Fig.24D L1 / HWP1 2308, L2 / HWP2 2312 and L3 / HWP3 2304B in the embodiment may have a superimposed lens effect. Thereafter, when emitted from the adaptive lens assembly 1700B in the deactivated state, the light beam 1732A may be seen by the eye.

[0357] In some embodiments, the first optical power -P1 of L1 / HWP1 2308 and the second optical power -P2 of L2 / HWP2 2312 may both be negative (i.e., divergent) and may have substantially the same or matching magnitudes. Additionally, the third optical power -P3 of L3 / HWP3 2304B may be negative. In these embodiments, the net optical power Pnet of the integrated broadband adaptive lens assembly 2400B may be approximated as -(P1+P2+P3). However, embodiments are not limited thereto, and in some other embodiments, the third optical power +P3 of L3 / HWP3 2304B may be positive. In these embodiments, the net optical power Pnet of the integrated broadband adaptive lens assembly 2400B may be approximated as -(P1+P2)+P3. Additionally, the first and second optical powers P1, P2 may have different magnitudes.

[0358] Although in the illustrated embodiment, the incident beam 1720 has a LHCP, a parallel result will be produced when the incident beam 1720 has a RHCP. That is, when the beam 1720 has a RHCP, unlike the illustrated embodiment, the resulting beam 1732B has a LHCP and can be converged by L1 / HWP1 2308, L2 / HWP2 2312, and L3 / HWP3 2304B according to the net optical power Pnet=+(P1+P2+P3).

[0359] Above about Fig.24D The described lens effect of L1 / HWP1 2308, L2 / HWP2 2312 and L3 / HWP 2304B and the dependence of the lens effect on the polarization state of the incident light beam are only an example, and other configurations are possible. For example, unlike the illustrated embodiment, L1 / HWP1 2308, L2 / HWP2 2312 and the deactivated L3 / HWP3 2304B can be configured to converge light with LHCP while diverging light with RHCP.

[0360] In the above, it has been described that when configured as above about Fig.11A The second adaptive lens assembly 1008 on the user side of the display device 1100A is described as being in a deactivated state of the integrated broadband adaptive lens assembly 2400B. Fig. 11B As described above, activating the second adaptive lens assembly 1008 to display virtual content to the user's eye 210 without any compensating effect may result in defocus or distortion of the real world view, which is undesirable. Therefore, it is desirable to configure the first adaptive lens assembly 1004 on the world side to at least partially compensate or cancel the lens effect of the second adaptive lens assembly 1008 that is deactivated to display virtual content.

[0361] Return to reference Fig.24D , when configured as the first adaptive lens assembly 1004 on the world side ( Fig. 11B ) to offset the second adaptive lens assembly 1008 on the user side ( Fig. 11B ) lens effect, the components of the adaptive lens assembly 1700B can be arranged as described above with respect to Fig. 11B That is, when light transmitted from the world 510 to the eye 210 passes through the first and second adaptive lens assemblies 1004, 1008, each adaptive lens assembly can be configured as described above with respect to the integrated broadband adaptive lens assembly 2400B (with respect to Fig.24DIn operation, as described above, the polarization of light transmitted from the world through the first adaptive lens assembly 1004 is transformed from a first polarization state to a second polarization state, for example, from RHCP to LHCP. Subsequently, the polarization of light transmitted through the second adaptive lens assembly 1008 is transformed from the second polarization state back to the first polarization state, for example, from LHCP to RHCP. In addition, as described above with respect to Fig. 11B As described, light transmitted from the world through the first adaptive lens assembly 1004 experiences a first lens effect (e.g., a converging effect) according to a first net optical power Pnet1=(P1+P2+P3) having a first sign (e.g., a positive sign). Subsequently, light transmitted through the second adaptive lens assembly 1008 experiences a second lens effect (e.g., a diverging effect) opposite to the first lens effect according to a second net optical power Pnet2=-(P1′+P2′+P3′) having a second sign (e.g., a negative sign), because the light incident on the second adaptive lens assembly 1008 has a polarization opposite to that of the light incident on the first adaptive lens assembly 1004. When Pnet1 and Pnet2 have substantially similar sizes, the total lens effect approximated by P=Pnet1+Pnet2 can be substantially zero. Therefore, when the user views virtual content and views real objects in the surrounding world by activating the second lens assembly 1008, the world view is relatively unaffected by the compensation effect of the first lens assembly 1004.

[0362] In various embodiments, when deactivated, each of the first and second adaptive lens assemblies 1004, 1008 can provide a net optical power (positive or negative) within a range of approximately between ±5.0 Diopters and 0 Diopters, between ±4.0 Diopters and 0 Diopters, between ±3.0 Diopters and 0 Diopters, between ±2.0 Diopters and 0 Diopters, between ±1.0 Diopters and 0 Diopters, including any ranges bounded by these values, such as ±1.5 Diopters.

[0363] Fig.25A and 25B is shown with an integrated broadband adaptive lens assembly 2400 ( Fig.24A / 24B) corresponding to the transmission spectra 2500A, 2500B, wherein L3 / HWP3 2304 is deactivated ( Fig.24C ) and activated( Fig.24D). The simulation corresponds to an integrated broadband adaptive lens assembly 2400, wherein L3 / HWP3 2304 includes a switchable LC layer 2304 formed of an unpolymerized LC layer having a thickness of 10 μm and a Δn of 0.2 (e.g., the switchable LC layer 2304 in FIG. 23 ), and each of L1 / HWP1 2308 and L2 / HWP2 2312 includes a polymerized LC layer formed of polymerized twisted LC molecules having a twist angle of 60 degrees (e.g., Fig.24A As shown in graph 2500A, when L3 / HWP3 2304A is deactivated ( Fig.24C ), the diffraction efficiency is high, and thus the light leakage is low (maximum about 20%), indicating that the incident light is effectively diffracted by the integrated broadband adaptive lens assembly 2400A, and there is essentially no light leakage between 400nm and 800nm. On the other hand, as shown in the graph 2500B, when L3 / HWP3 2304B is activated ( Fig.24D ), the diffraction efficiency is very low, and the incident light is transmitted almost without diffraction (about 100%), indicating that most of the incident light is not diffracted when passing through the integrated broadband adaptive lens assembly 2400A between 400nm and 800nm.

[0364] Chromatic aberration reduction in broadband adaptive lens assemblies

[0365] Despite high efficiency over a wide wavelength range, some broadband adaptive lens assemblies may have a focal length or optical power that depends substantially on the wavelength of light, resulting in significant chromatic aberration. This is because, for larger focal lengths, the lens optical power is proportional to the corresponding wavelength. That is, for different wavelengths of the waveplate lens, the dependence of the optical power P(λ) can be approximated as: P(λ B )=P(λ G ) B / λ G and P(λ R )=P(λ G ) R / λ G , where B, G, and R correspond to wavelengths in the blue spectrum, wavelengths in the green spectrum, and wavelengths in the red spectrum, respectively. Therefore, there is a need to reduce chromatic aberration in a broadband adaptive lens assembly. In the following, a method of reducing chromatic aberration is described according to an embodiment.

[0366] In the above, for example, Figures 23A to 23D , have disclosed embodiments of a broadband adaptive lens assembly having two switchable broadband wave plate lenses that produce 2 for light having circular polarization 2= 4 optical power states. By extension, a stack comprising more than two (N) switchable broadband waveplate lenses can be formed, which has 2 N For example, for a broadband adaptive lens assembly with three switchable broadband waveplate lenses (N=3), eight power states can be achieved. Table 1 shows the calculated power of a broadband adaptive assembly including three switchable broadband waveplate lenses, each of which is similar to the above example with respect to Figures 22A to 22C A switchable broadband wave plate lens is described.

[0367] Table 1

[0368]

[0369] For a broadband adaptive assembly with three switchable broadband waveplate lenses, the net lens power can be expressed as P net =((S1*P1+P2)*S2+P3)*S3, where P i and S i = ± 1 (i = 1, 2, 3) are the optical power and optical power state of each switchable broadband wave plate lens. For example, the activated state can be represented as S = +1, and the deactivated state can be represented as S = -1. Referring to Table 1, the columns labeled "State 1" to "State 8" correspond to different lens states of each of the three lenses, and the rows "Blue", "Green" and "Red" represent the calculated optical power at wavelengths of 450nm, 525nm and 632nm, respectively (representing the blue, green and red colors of light, respectively). In the calculation, it is assumed that only light with one polarization (e.g., the first circular polarization) reaches the eye, while other light is recycled or reflected. For the purpose of illustration, at the green wavelength (525nm), the optical power of three separate broadband wave plate lenses is calculated to be 0.5D, 0.5D and 1.5D. Based on Table 1, it can be seen that in order to obtain the target net optical power of 0.5D, 1.5D and 2.5D, lens state 3, state 5 and state 1 can be selected. However, it is observed that for a target net power of 2.5D at the red wavelength, the net power at the blue and red wavelengths (450nm and 632nm) causes significant chromatic aberration, for example as much as 0.51D.

[0370] However, the inventors have realised that chromatic aberrations can be significantly reduced if, instead of using one state to achieve one target net power for the three colours shown in Table 1, more than one state is used to achieve a given target net power for different colours. This approach is shown in Table 2.

[0371] Table 2

[0372]

[0373] Referring to Table 2, chromatic aberration can be significantly reduced by using more than one state to achieve a given target net optical power and slightly different target lens powers for different colors. Here, the optical powers of the three individual broadband waveplate lenses are 0.4D, 0.7D, and 1.6D at the green wavelength (525nm). Based on Table 2, it can be seen that in order to obtain a target net optical power of 0.5D, a single lens state 3 can be selected. However, to reduce chromatic aberration, for a target net optical power of 1.5D, states 5 and 7 can be selected, while for a target net optical power of 2.5D, states 1 and 5 can be selected. Compared to the chromatic aberration of 0.51D for the target net optical power of 2.5D shown in Table 1, by using more than one state for different colors, the chromatic aberration of the target net optical power of 2.5D at the red wavelength can be reduced to 0.2.

[0374] Fig.26A , 26B 2600A, 2600B, and 2600C are graphs 2600A, 2600B, and 2600C showing calculated target net powers versus actual net powers for blue, green, and red wavelengths, respectively, according to an embodiment, showing improved chromatic aberration performance obtained by using a method of achieving target net powers for different color wavelengths with different lens states. Within each of graphs 2600A, 2600B, and 2600C, black solid lines 2612, 2622, and 2632 represent the target net powers, dashed lines 2604, 2614, and 2624 represent the calculated powers when using the method of obtaining a given power described above with respect to Table 1 with a single lens state, and gray solid lines 2608, 2618, and 2628 represent the calculated powers when using the method of obtaining a given power described above with respect to Table 2 with multiple lens states. As observed, when multiple lens states are used to obtain a given power, the actual power is closer to the target power.

[0375] Fabrication of Broadband Wave Plates and Wave Plate Lenses Using Photoalignment Techniques

[0376] Figures 27A to 27C An example method for preparing a broadband wave plate or a broadband wave plate lens is shown. Fig.27A The intermediate structure 2700A provides a transparent substrate 1312 on which the alignment layer 1302-0 is formed. The transparent substrate 1312 may include, for example, silicon dioxide, sapphire, or any suitable transparent material. It should be understood that, although not shown, according to various embodiments described herein, additional structures and layers may be present on the substrate 1312, resulting in the formation of the alignment layer 1302-0. By way of example, when forming the switchable wave plate 1300F ( Fig.13F ), before forming the alignment layer 1302-0, the first transparent electrode layer in the transparent electrode layers 1316 and 1320 may exist on the substrate 1312 before forming the alignment layer 1302-0.

[0377] In some embodiments, the alignment layer 1302-0 may be a photo-alignment layer, and when the LC molecules are deposited, the LC molecules on the photo-alignment layer may become oriented along a preferential direction, for example, due to the anchoring energy applied by the photo-alignment layer to the liquid crystal molecules. Examples of the photo-alignment layer include polyimide, linearly polarized light polymerized polymer (LPP), azo-containing polymers, coumarin-containing polymers, and cinnamate-containing polymers as several examples, as well as the above-referenced Fig. 13C , 13F Other compounds described.

[0378] The alignment layer 1302-0 can be formed by dissolving a precursor (e.g., a monomer) in a suitable solvent and then coating the solution on the substrate 1312 using a suitable process (e.g., spin coating, slot coating, doctor blade coating, spray coating, jet (inkjet) coating, and other deposition processes). The solvent can then be removed from the coating solution. The alignment layer 1302-0 can also be cured (e.g., UV cured) using a polarizer in preparation for subsequent alignment of the LC molecules on the alignment layer 1302-0.

[0379] refer to Fig.27B After the alignment layer 1302-0 is coated, the alignment layer 1302-0 is optically patterned or recorded. The holographic double beam exposure process ( Fig.28 ) or optical replication using a master lens and single beam exposure process ( Fig.29A , 29B ) to perform optical patterning.

[0380] refer to Fig.27C The intermediate structure 2700C is formed on the alignment layer 1302-0 after coating the LC layer 2704. The LC layer 2704 can be formed by depositing a reactive liquid crystal element mixture (including, for example, liquid crystal monomers, solvents, photoinitiators, and surfactants) on the alignment layer 1302-0 using a suitable process (including, for example, spin coating, slot coating, doctor blade coating, spray coating, inkjet coating, and other deposition processes).

[0381] As described above, when the LC layer 2704 is integrated as part of a passive wave plate lens or a switchable wave plate, the LC layer 2704 may be cured (eg, UV cured) to photopolymerize the LC layer 2704 so that the LC molecules may become fixedly oriented.

[0382] In contrast, as described above, when the LC layer 2704 is integrated as part of a switchable wave plate lens or a switchable wave plate, the LC layer 2704 can be further processed without polymerizing the LC layer 2704 so that the LC molecules can reorient themselves in response to a switching signal.

[0383] When deposited, at least the bottom-most LC molecules in the liquid crystal (LC) layer 2704 that are located immediately above the alignment layer 1302-0 can self-organize according to the configuration of the alignment layer 1302-0, depending on the various applications described herein. For example, as described above, when the LC layer 2704 forms part of a broadband wave plate lens, the alignment layer 1302-0 is configured so that the bottom-most LC molecules have a radius along the LC layer 2704 (in the range from, for example, the above description of the alignment layer 1302-0 to the bottom-most LC molecules). Fig.16A , 16B , 19A). In addition, when the LC layer 2704 forms part of a broadband wave plate, the alignment layer 1302-0 is configured so that the bottommost LC molecules have their long axes approximately aligned as, for example, with respect to Fig.13A , 13C The local orientation or director is oriented in a manner extending in the first transverse direction. Still referring to Fig.27C In some embodiments, as described elsewhere in this application, LC molecules located above the bottommost LC molecules in the LC layer 2704 may be configured to be arranged differently from the bottommost LC molecules in the LC layer 2704. For example, the topmost LC molecules in the LC layer 2704 may be aligned differently by a second alignment layer formed on the LC layer 2704. In addition, the LC molecules between the topmost LC molecules and the bottommost LC molecules may have a twist, as described with respect to various embodiments, including Fig. 13C and 20A / 20B.

[0384] After deposition of the LC layer 2704 and optional polymerization, the intermediate structure 2700C may be further processed to form additional structures and / or layers, as described in accordance with various embodiments described herein. For example, when forming the switchable wave plate 1300F ( Fig.13F ), after forming the LC layer 2704, the intermediate structure 2700C may be further processed, for example, to form a second alignment layer 1302-0 on the LC layer 2704 and to form a second transparent electrode layer in the transparent electrode layers 1316, 1320. In addition, in some embodiments, an additional LC layer may be formed on the LC layer 2704, wherein the bottommost LC molecules of the subsequent LC layer are aligned with the topmost LC molecules of the previous LC layer, such as Fig.13F and 24A described.

[0385] Fig.28 The dual beam exposure process sometimes referred to as polarization holography is shown to configure the above Fig.27C The alignment layer is described as an example method to align LC molecules in a broadband wave plate or broadband wave plate lens. While most conventional holography uses intensity modulation, polarization holography involves polarization state modulation due to the interference of light with different polarizations. Reference Fig.28 The intermediate structure 2800 shown includes forming an unpolymerized photo-alignment layer 1302-0 on the substrate 1312, as described above with respect to Fig.27A As described. Thereafter, a plurality of coherent light beams (e.g., RHCP light beam 2808 and LHCP light beam 2804) with different polarizations are directed to the alignment layer 1302-2. In the illustrated embodiment, the RHCP light beam 2808 and the LHCP light beam 2804 are orthogonal circularly polarized light beams. While one of the RHCP light beam 2808 and the LHCP light beam 2804, which can be used as a reference beam, is collimated, the other of the RHCP light beam 2808 and the LHCP light beam 2804, which can be used as a recording beam, converges or diverges. However, the embodiments are not limited thereto. For example, the orthogonal polarized light beams may include a linear vertically polarized light beam and a linear horizontally polarized light beam or a linearly polarized light beam of ±45 degrees. In some embodiments, a UV laser (e.g., HeCd, 325nm) with orthogonal circular polarization may be used to perform dual-beam exposure of the alignment layer 1302-0 to a polarization hologram. Depending on the liquid crystal material and the grating parameters (e.g., thickness d), a typical recording dose may be about several J·cm -2 Thereafter, a reactive mesogen mixture (including, for example, liquid crystal monomers, solvents, photoinitiators, and surfactants) is applied so as to be aligned according to the surface pattern formed by dual-beam exposure, as described above with respect to Figures 27A to 27C described.

[0386] Figures 29A to 29B An exemplary method for configuring an alignment layer to align liquid crystal molecules in a broadband wave plate or broadband wave plate lens is shown by preparing a master wave plate or wave plate lens having a master alignment pattern of LC molecules and replicating the master alignment pattern of LC molecules onto a target alignment layer using the master wave plate or wave plate lens. Fig.28 Unlike the described dual beam exposure method in which the interference of two orthogonal polarized light beams is used to directly arrange the alignment layer, in this illustrated embodiment, a master wave plate lens and one polarized light beam are used to produce a similar polarization hologram in the near field. Therefore, once a master lens with a master alignment pattern of LC molecules is prepared, it can be used as a template and a relatively simple single beam exposure is used to prepare multiple wave plates and wave plate lenses.

[0387] Fig.29AA primary wave plate or wave plate lens 2904 is shown. The primary wave plate or wave plate lens 2904 may be used, for example, as described above with respect to Figures 27A to 27C and 28, which includes forming an alignment layer using a light interference pattern formed by, for example, a dual-beam exposure process, followed by forming a reactive liquid crystal element (RM) mixture layer (including, for example, a liquid crystal monomer, a solvent, a photoinitiator, and a surfactant) that is self-aligned with the alignment layer, and then performing blanket UV curing on the RM mixture layer to polymerize the LC molecules in the RM mixture layer. Fig.29A Further shown is an operational diagram 2900A of a primary wave plate or wave plate lens 2904 which is designed to have finite diffraction efficiency such that only a portion of polarized incident light is diffracted while a portion is passed unaffected. For example, in the illustrated embodiment, the primary wave plate or wave plate lens 2904 is configured to diffract a portion (e.g., 30-70%, 40%-60%, 45-55%, or any value within these values, for example, approximately 50%) of incident light 2908 having a first polarization (e.g., RHCP) as diffracted light 2912 having a second polarization (e.g., LHCP), while allowing a portion (e.g., 30-70%, 40%-60%, 45-55%, or any value within these values, for example, approximately 50%) of the incident light 2908 to pass through the primary lens 2904 without diffraction as leakage light 2916 (e.g., zero-order leakage light, which has the same first polarization (e.g., RHCP) as the incident light beam 2908).

[0388] Fig.29B As shown above, Fig.29A The fabricated and configured main lens 2904 and the intermediate structure including the alignment layer 1302-0 for aligning LC molecules in a broadband wave plate or broadband wave plate lens are shown in an exemplary fabricated configuration 2900B. Fig.29B Preparation configuration 2900B, as above for Fig.27A As described above, the intermediate structure shown includes an unpolymerized photo-alignment layer 1302-0 located on a substrate 1312. The preparation configuration 2900B includes a main lens 2904 arranged above the unpolymerized photo-alignment layer 1302-0. An incident light beam 2908 having a first polarization (e.g., RHCP) is directed to the alignment layer 1302-2. As described above with respect to Fig.29A As described above, since the main wave plate or wave plate lens is designed to diffract only a portion of the incident light, two light beams with opposite polarizations are incident on the alignment layer 1302-0 when passing through the main wave plate or wave plate lens 2904. In fact, the effect of the two light beams incident on the alignment layer 1302-0 is similar to the above description of Fig.28In the example shown, what is transmitted through the main wave plate or wave plate lens 2904 and incident on the alignment layer 1302-0 is a diffracted beam 2912 having a second polarization (e.g., LHCP) opposite to the first polarization (e.g., RHCP) of the incident beam 2908 and a leakage beam 2916 having the same first polarization (e.g., RHCP) as the incident beam 2908. Thus, in the same manner as described above with respect to Fig.28 In a similar manner, the diffracted beam 2912 can converge or diverge and can be used as a recording beam, while the leakage beam 2916 can be used as a reference beam. The interference of the diffracted beam 2912 and the leakage beam 2915 causes the alignment layer 1302-0 to occur in a similar manner as described above with respect to FIG. 20. Thereafter, a reactive mesogen mixture (including, for example, a liquid crystal monomer, a solvent, a photoinitiator, and a surfactant) can be applied to align it according to the surface pattern formed by the dual beam exposure, as described above with respect to FIG. Figures 27A to 27C Therefore, advantageously, once the above Fig.28 The relatively complex dual beam exposure method described above can be used to prepare the main lens 2904. Fig.29B The subsequent configuration of the alignment layer can be performed using the relatively simple single beam exposure described above. Advantageously, in some cases, a fully coherent light source (e.g., a laser) or a partially coherent light source (e.g., a UV lamp or a light emitting diode, etc.) can be used, similar to the above description of Fig.28 Compared to the dual beam exposure method described above, the described method uses less precise optics, less vibration control, and looser alignment to perform the Fig.29B The method shown.

[0389] Fabrication of Broadband Wave Plates and Wave Plate Lenses Using Nanoimprint Alignment Layers

[0390] As described throughout the application, in various embodiments, an alignment layer (e.g., a photo-alignment layer that can be configured using light) can be used to align LC molecules in the LC layer of broadband wave plates and wave plate lenses according to various embodiments. In other embodiments, patterned nanostructures can be used to align LC molecules. Fig. 30A and 30B In the following, a method of aligning LC molecules using patterned nanostructures is described, followed by Fig. 30C Examples of patterned nanostructures suitable for use as wave plate lenses are described.

[0391] Fig. 30A and 30B Cross-sectional views of intermediate structures 3000A, 3000B are shown, respectively, at different stages of fabrication using a nanoimprint process, according to some embodiments.

[0392] refer to Fig. 30AThe intermediate structure 3000A of FIG. 10 is a structure of FIG. 100A, wherein a transparent substrate 1312 is provided in a manner similar to that described above with respect to various embodiments. A nanoimprint template (not shown) or nanoimprint mold having a predefined topological pattern configured to form a subsequently formed LC layer 2704 ( Fig. 30B ) in the LC layer 2704 (e.g., at least the bottommost LC molecules in the LC layer 2704 closest to the substrate 1312). Subsequently, the template is pressed into a blanket base polymer layer, which may include a thermoplastic polymer at a specific temperature (e.g., above the glass transition temperature of the blanket base polymer layer), thereby transferring the template pattern to the softened blanket base polymer layer to form an imprinted alignment layer 3004. After cooling, the template is separated from the imprinted alignment layer 3004, which includes an alignment pattern having a predefined topological pattern, and the topological pattern is configured to form an alignment pattern of LC molecules in the subsequently formed LC layer 2704 ( Fig. 30B ). In some other methods, after being pressed into the base polymer layer, the imprinted alignment layer 3004 is hardened by cross-linking under UV light.

[0393] The imprinted alignment layer 3004 may include features with sub-wavelength dimensions. For example, the imprinted alignment layer 3004 may include features with dimensions (e.g., length, width, and / or depth) of approximately several nanometers, hundreds of nanometers, and / or several micrometers. As another example, the imprinted alignment layer 3004 may include features with a length greater than or equal to approximately 20nm and less than or equal to approximately 100nm. As yet another example, the imprinted alignment layer 3004 may include features with a width greater than or equal to approximately 20nm and less than or equal to approximately 100nm. As yet another example, the imprinted alignment layer 3004 may include features with a depth greater than or equal to approximately 10nm and less than or equal to approximately 100nm. In various embodiments, the length and / or width of the feature may be greater than the depth of the feature. However, in some embodiments, the depth may be approximately equal to the length and / or width of the feature. The features of each domain of the imprinted alignment layer 3004 may be arranged to form a complex geometric pattern within each domain, wherein the direction and / or period between consecutive features varies along a length scale on the order of nanometers, hundreds of nanometers, and / or micrometers.

[0394] Although about Fig. 30AAn example process of nanoimprinting for forming the nanoimprinted alignment layer 3004 is described, however, the embodiments are not limited thereto. In other embodiments, other patterning techniques including photolithography and etching may be used to prepare the imprinted alignment layer 3004. In addition, although the imprinted alignment layer 3004 is described as being formed of a polymer material, the embodiments are not limited thereto, and in various other embodiments, the imprinted alignment layer 3004 may include a dielectric material, such as silicon or a glass material.

[0395] refer to Fig. 30B The intermediate structure 3000B, after forming the alignment layer 3004, according to the above Figures 27A to 27C The deposition process described above is described, on which an unpolymerized LC layer 2704, such as a reactive mesogen layer, is deposited. Without being bound by any theory, the imprinted alignment layer 3004 serves as an alignment layer that aligns the LC molecules of the LC layer 2704 according to the pattern of the imprinted alignment layer 3004. For example, the elongation direction of the LC molecules within the domain may be aligned in a direction substantially parallel to the local elongation direction of the nanostructures in the imprinted alignment layer 3004. Without being bound by any theory, the alignment of the LC molecules with the pattern of the imprinted alignment layer 3004 may be attributed to spatial interactions with the liquid crystal molecules and / or anchoring energy exerted by the imprinted alignment layer 3004 on the deposited LC molecules.

[0396] Still refer to Fig. 30B The intermediate structure 3000B can be based on the above Figures 27A to 27C Various embodiments are described for further processing of the LC layer 2704, including polymerization, further alignment of LC molecules above the bottommost LC molecules, and stacking of multiple LC layers.

[0397] Fig. 30C It shows that according to the above Figures 30A to 30B 3004. The embossed alignment layer 3004 can be used as an alignment layer to form a layer of LC molecules having various lateral arrangements as described herein, including, for example, those described above with respect to Fig.13A , 13C , the arrangements described in 16A, 16B, 19A, and other arrangements.

[0398] According to various embodiments, when the LC layer formed according to the imprinted alignment layer 3004 forms a part of a wave plate lens, the imprinted alignment layer 3004 according to various embodiments includes a plurality of regions, for example, concentric regions 3008-1, 3008-2, ... 3008-n in the xy plane. The imprinted nanostructures within each region of the imprinted alignment layer 3004 are oriented along a specific direction. The orientations of the molecules of the liquid crystal material in adjacent regions may be different. For example, the elongation directions or local directors of the LC molecules in the respective regions 3008-1, 3008-2, ... 3008-n may be oriented according to a power r that depends on the radius from the center position. n The invention is a function of the rotation in the radial direction, wherein n can vary from about 1 to 3, such as for example Fig.16A / 16B and Figure 19.

[0399] The imprinted nanostructures and the formed liquid crystal molecules may have different elongation directions in different regions 3008-1, 3008-2, ... 3008-n. For example, the elongation directions of the imprinted nanostructures in the continuous region may be rotated at an angle of about 18 degrees relative to each other in the clockwise direction. However, the embodiment is not limited thereto, and the relative rotation angle between the continuous regions may be less than 1 degree, between about 1 degree and 45 degrees, between about 1 degree and 18 degrees, or between about 18 degrees and 45 degrees.

[0400] Integration of broadband adaptive lens assemblies with broadband wave plates and / or wave plate lenses

[0401] According to various embodiments described above, for example, a broadband adaptive lens assembly includes an integrated wave plate and a wave plate lens. Hereinafter, a method of integrating a wave plate and a wave plate lens is described according to an embodiment. Figures 31A to 31C An example method for preparing a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal using a gap filling process is shown. According to various embodiments, the method includes providing a lower stack, the lower stack including a first electrode layer located on a first substrate and a first alignment layer formed on the first electrode layer, and the method also includes providing an upper stack, the upper stack including a second electrode layer located on a second substrate and a second alignment layer formed on the second electrode layer. The first stack and the second stack are then stacked into a single stack so that the first and second alignment layers face each other, wherein a spacer is formed between the lower stack and the upper stack to create a gap therebetween, and the gap is subsequently filled with a liquid LC layer material. Reference Fig.31A The method includes following the above example with respect to Fig.27A Provide a substrate 1312 in a similar manner, and then follow the above example with respect to Fig.27A In a similar manner, a first electrode layer 1320, such as a transparent electrode layer, is formed on the substrate 1312. Fig.31B, a first alignment layer 1302-0 is formed on the substrate 1312, thereby forming the lower stack 3100A. The alignment layer 1302-2 may be similar to that described above with respect to, for example Figures 27A to 27C , 28 and 29, or a photo-alignment layer similar to that described above with respect to, for example Figures 30A to 30C An imprinted alignment layer is described.

[0402] refer to Fig. 31C , in a manner similar to that of forming the lower stack 3100A, an upper stack 3100B is formed, the upper stack 3100B comprising a second substrate 1312, on which a second substrate 1312 is formed in a manner similar to that of forming the lower stack 3100A (as described above with respect to Fig.31B The method further comprises forming a first electrode layer 1320 (eg, a transparent electrode layer) and a second alignment layer 1302-0.

[0403] In some embodiments, the first and second alignment layers 1302-0 (which may be photo-alignment layers or imprinted alignment layers) may be configured differently, as described above with respect to various embodiments, so that the LC molecules adjacent to the first and second alignment layers 1302-0 are aligned differently, for example, aligned so that the elongation directions or pointing vector directions of the LC molecules cross each other, for example, at an angle of approximately 90 degrees.

[0404] Still reference Fig. 31C , the upper and lower stacks 3100B, 3100A are then stacked into a single stack so that the first and second alignment layers 1302-0 face each other with a gap 1302 formed therebetween. The gap 1302 may be formed by a spacer 1350 formed between the lower and upper stacks 3100A, 3100B.

[0405] The spacer 1350 may be formed of a suitable material, such as silica beads having a diameter that creates a gap whose distance defines the target thickness of the subsequently inserted LC material. In some embodiments, the spacer 1350 in the form of silica beads may be dispersed on the surface of one or both of the upper and lower stacks 3100B, 3100A using a dry process. In other embodiments, the spacer 1350 in the form of silica beads may be mixed with an adhesive and applied to the surface edge of one or both of the upper and lower stacks 3100B, 3100A. Thereafter, the upper and lower stacks 3100B, 3100A are pressed toward each other until a final gap distance corresponding to the resulting LC layer thickness is obtained. The gap distance may be monitored using Fabry-Perot interference fringes.

[0406] After the gap 1302 is formed, an LC material is inserted into the gap 1302. As described above, the inserted LC material may be a reactive liquid crystal element mixture, which includes, for example, a liquid crystal monomer, a solvent, a photoinitiator, and a surfactant. The LC material may be inserted into the gap 1302 by capillary forces. In some embodiments, the insertion is performed under vacuum.

[0407] Above about Figures 31A to 31C The described integration process can be applied to any suitable embodiment described herein. For example, the method can be used to form a similar Fig.13F The switchable broadband wave plate comprises the switchable TN LC layer 1302 ( Fig.13F ) a pair of wideband QWPs 1324, 1326 ( Fig.13F In these embodiments, the lower stack 3100A includes a QWP 1324 ( Fig. 13B ) of multiple TNLC layers 1302-1, 1302-2 ( Fig.13F ), the upper stack 3100B similarly includes a QWP 1326 ( Fig. 13B ) of multiple TN LC layers 1302-1, 1302-2 ( Fig.13F ).

[0408] To provide another example, the above description of Figures 31A to 31C The integration process described above is applied to form Fig.24A The integrated broadband adaptive lens assembly comprises a switchable TN LC layer 2304 ( Fig.24A ) a pair of polymerized LC (LCP) layers 2302-1, 2302-2 ( Fig.24A ), a switchable TNLC layer 2304 is inserted into the above gap 1302 to serve as L3 / HWP3 2304 ( Figures 23B to 24D In these embodiments, the lower stack 3100A includes L1 / HWP2 2308 ( Figures 24B to 24D ) of the lower polymerized LC (LCP) layer 2302-1 ( Fig.24A ), the upper stack 3100B similarly includes L2 / HWP2 2312 ( Figures 24B to 24D ) of the upper polymerized LC (LCP) layer 2302-2 ( Fig.24A ).

[0409] In the following, methods of integrating wave plates and wave plate lenses according to some other embodiments are described. Figures 32A to 32EIn the present invention, an example method of preparing a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal adopts a layer transfer process. In the layer transfer process, the LC layer is formed on a donor, sacrificial or carrier substrate, which may be flexible, and then transferred to a permanent substrate, which may be rigid. Forming the LC layer on such a carrier substrate may allow for higher production throughput and / or higher manufacturing yield.

[0410] Fig.32A An intermediate structure 3200A is shown that includes a carrier substrate 3204, which may be a suitable substrate that is sufficiently flexible while having sufficient thermal stability for subsequent processing, including polymerization of the LC layer on which the alignment layer 1302-0 is formed. The alignment layer 1302-0 may be of the same type as described above with respect to, for example, Figures 27A to 27C , 28 and 29, or may be a photo-alignment layer formed and configured in a manner similar to that described above with respect to, for example Figures 30A to 30C The embossed alignment layer is formed and configured in a similar manner as described above.

[0411] Fig.32B An intermediate structure 3200B including a release layer 3208 formed on an alignment layer 3208 is shown. Fig.32C An intermediate structure 3200C is shown including an LC layer 3212 formed on a lift-off layer 3208, thereby temporarily bonding the LC layer 3212 to the alignment layer 3208. The LC layer 3212 may be formed in the same manner as described above with respect to Fig.27C Formed and configured in a similar manner as described above.

[0412] In some embodiments, the peeling layer 3208 includes a thin surface layer formed by surface treatment, which weakens the adhesive strength between the LC layer 3212 and the alignment layer 1302 - 0 but does not substantially affect the alignment property of the alignment layer 3208 .

[0413] In some embodiments, the peeling layer 3208 is a separate suitable thin film coated on the alignment layer 1302-0, and the adhesive strength of the film to the underlying layer is higher than the adhesive strength to the layer above the peeling layer 3208. In the example shown, the peeling layer 3208 is formed between the alignment layer 1302-0 and the LC layer 3212 ( Fig.32C ). Therefore, according to some embodiments, the peeling layer 3208 is formed of a suitable material that forms a stronger bonding interface with the alignment layer than the LC layer 3212, so that when a mechanical force is applied, the peeling layer 3208 is relatively easier to separate from the LC layer 3212 than the alignment layer 3202-2.

[0414] In some embodiments, the peeling layer 3208 includes a separate liquid curable adhesive coated on the peeling layer 3208, which can be cured in situ when exposed to UV light for curing the LC layer 3212. Curing converts the adhesive layer into a 3D polymer network that is resistant to flow before separation. In some other embodiments, the peeling layer 3208 includes a separate thermoplastic bonding material coated on the peeling layer 3203, rather than a curable adhesive material. The thermoplastic bonding material includes a thermoplastic polymer that is not cross-linked or cured, but reversibly softens and then re-hardens into a glassy state when cooled to room temperature. At room temperature, the thermoplastic bonding material forms a rigid and resilient bonding agent that allows subsequent processes to be performed without substantial deformation.

[0415] Fig.32D An intermediate structure 3200D is shown comprising a target substrate 1312 (which may be a permanent substrate) attached to an LC layer 3212 using a glue layer 3216. The substrate 1312 may be any transparent substrate described elsewhere in this specification.

[0416] Fig.32EAn intermediate structure 3200e is shown in which a target stack including a target substrate 1312 attached to an LC layer 3212 by a glue layer 3216 is separated from a carrier stack including a carrier substrate 3204, an alignment layer 1302-0, and a peeling layer 3208. In some embodiments, the separation is performed by mechanical debonding (sometimes referred to as peeling separation). The separation occurs at the interface between the peeling layer 3208 and the LC layer 3212, for example, at the peeling layer 3208 that has been surface treated or one of the different types of separately deposited peeling layers described above. The separate peeling layer 3208 or surface treatment is designed to have sufficient adhesion at its interface so that the bonded structure can withstand normal process stresses, but the bond strength is not yet too strong, so a strong force that can interrupt the thin device wafer is required to separate between these layers. The separation process may include inducing delamination between the peeling layer 3208 and the LC layer 3212 at an edge interface (this edge interface extends over the entire interface between the peeling layer 3208 and the LC layer 3212) using a very small force that causes separation. The use of thermoplastic bonding materials and low surface energy polymer peeling layers (which may be curable or thermoplastic compositions) is suitable for mechanical debonding. However, the embodiments are not limited thereto, and in some other embodiments, the separation involves sliding debonding. These embodiments utilize the reversible softening behavior of thermoplastic bonding materials. In this mode, the bonded structure is heated to above the softening temperature of the bonding material, and opposite shear forces are applied to the device and the carrier wafer, causing them to slowly slide over each other until the structure is separated. In some other embodiments, the separation involves laser debonding. In these embodiments, when the scanning laser irradiates through the carrier substrate 3204, the laser beam is used to ablate the peeling layer 3208 or decompose the peeling layer 3208 into gaseous byproducts and a small amount of carbon-containing residue.

[0417] Still reference Fig.32E , the LC layer 2704 on the separated target stack can be further processed, and can be further processed according to different embodiments, as described above with respect to Figures 27A to 27C The above-mentioned steps include polymerization, further alignment of LC molecules above the bottommost LC molecules, and stacking of multiple LC layers.

[0418] Formation of broadband adaptive lens components on selected substrate areas

[0419] As described above with respect to various display devices (e.g., wearable display device 1000 ( Fig.10)) As described above, a broadband adaptive lens assembly (e.g., a pair of broadband adaptive lens assemblies 1004, 1008) may be formed in an optical path 1016 with a waveguide assembly 1012 interposed therebetween to display virtual images and world images. However, in some embodiments, as part of a wearable display device, the broadband adaptive lens assembly may be formed on a portion of a substrate, such as a portion of the waveguide assembly 1012 or a portion of a lens of goggles on which the eye 210 is expected to view a virtual image. Various embodiments of forming a broadband adaptive lens assembly on a selected substrate area are described below.

[0420] Fig.33 An example of a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal formed on a portion of a substrate 3300 is shown. The substrate 3300 may represent, for example, a portion of a waveguide component 1012 or a wearable display device 1000 (such as goggles or glasses). Fig.10 The substrate 3300 includes a lens region 3204 on which an optically active switchable broadband wave plate or a switchable broadband wave plate lens will be formed, and a clear region 3308 on which no switchable broadband wave plate or switchable broadband wave plate lens will remain.

[0421] Fig.34 A first example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate 3400 is shown by selectively coating or depositing an LC layer 3404 of the switchable broadband wave plate or broadband wave plate lens on the lens area 3204 while preventing them from forming in the blank area 3308. Figures 27A to 27C As described, the LC layer 3404 is first coated in the form of a reactive liquid crystal element mixture layer (including, for example, liquid crystal monomers, solvents, photoinitiators and surfactants), followed by suitable subsequent processes, such as solvent evaporation and optional polymerization (for polymerized LC layers). In some embodiments, each layer can be deposited using a suitable non-contact or contact process to perform selective coating, such as a slit-die coating process, a gravure coating process or a jet (inkjet) coating process.

[0422] Figures 35A to 35C An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by blanket coating a liquid crystal layer and performing subtractive removal is shown. Fig.35A , first on the substrate 3300 ( Fig.33) is formed on the entire area of ​​the liquid crystal element layer 3504 (which may include, for example, liquid crystal monomers, solvents, photoinitiators, and surfactants), and then a suitable subsequent process, such as solvent evaporation, is performed. Fig.35B , the reactive liquid crystal element layer in the lens area 3304 is selectively cured using an optical mask or photomask to block the UV light in the blank area 3308, thereby forming a polymerized LC layer 3508 in the lens area 3304, while the uncured reactive liquid crystal element layer 3512 in the blank area remains uncured (i.e., not polymerized). Next, referring to Fig.35C , the uncured reactive liquid crystal element layer 3512 is selectively removed from the blank area 3308 using a suitable solvent, thereby producing a selectively coated substrate 3500C having a polymerized LC layer 3508 selectively retained only in the lens area 3304.

[0423] Figures 36A to 36C An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by using selective optical patterning of an alignment layer is shown. Fig.36A In the intermediate structure 3600A shown, after blanket deposition of the photo-alignment layer, a first optical mask or reticle 3604 is used to cover the lens area 3304 while exposing the blank area 3308 to uniform linearly polarized light. Fig.36B The intermediate structure 3600B shown, by using a second optical mask or reticle 3616 whose mask pattern may be opposite to the first optical mask 3604, uses a dual beam exposure process such as described above with respect to FIG. 29 using orthogonally polarized UV laser beams to expose the lens area 3304 to a polarization hologram, while the blank area 3308 is covered. Fig.28 and 29A As described above, interference of light having orthogonal polarizations causes the alignment layer to be configured to align LC crystal molecules subsequently formed thereon according to the wave plate pattern or wave plate lens pattern described with respect to the various embodiments above. Thus, as a result of the arrangement of the first and second optical masks 3604, 3616, the alignment layer 3616 ( Fig.36B ) located in the lens region is selectively configured to align LC molecules subsequently formed thereon. In contrast, the alignment layer 3608 ( Fig.36A ) is configured differently and does not have the wave plate pattern or wave plate lens pattern described with respect to the various embodiments described above. Fig.36C The intermediate structure 3600C shown is similar to the above Figures 27A to 27CIn a similar manner, a reactive liquid crystal element layer 3620 (which may include, for example, liquid crystal monomers, solvents, photoinitiators, and surfactants) is blanket deposited over the entire substrate area including the blank area and the lens area, followed by appropriate subsequent processes including, for example, solvent evaporation and optional UV curing. Fig.36C In the resulting intermediate structure 3600C, although the entire surface area is covered with LC molecules, the LC molecules above the lens area are aligned according to the configuration of the underlying alignment layer and have a systematic orientation for functioning as a wave plate or a wave plate lens according to the various embodiments described above, while the LC molecules above the blank area do not have a systematic orientation for functioning as a wave plate or a wave plate lens.

[0424] Figures 37A to 37B An example method of forming a switchable broadband wave plate including liquid crystal or a switchable broadband wave plate lens including liquid crystal on a portion of a substrate by using a selective nanoimprint alignment layer is shown. Fig.37A The intermediate structure 3700A shown has a nanoimprinted alignment layer formed on the substrate surface, wherein the nanoimprinted alignment layer has different patterns between the lens region 3304 and the blank region 3308. In particular, the nanoimprinted alignment layer 3708 ( Fig.37A ) located in the lens region 3304 is configured to align the LC crystal molecules subsequently formed thereon according to the wave plate pattern or wave plate lens pattern described with respect to the various embodiments above. In contrast, the lens alignment layer 3608 ( Fig.37A ) is configured differently and does not have the wave plate pattern or wave plate lens pattern described with respect to the various embodiments described above. Fig.37B The intermediate structure 3700B shown is similar to the above Figures 27A to 27C In a similar manner, a reactive liquid crystal element layer 3712 (which may include, for example, liquid crystal monomers, solvents, photoinitiators, and surfactants) is blanket deposited on the blank areas 3308 and the lens areas 3304, followed by appropriate subsequent processes including, for example, solvent evaporation and optional UV curing. In the resulting intermediate structure 3600C, although the entire surface area is covered with LC molecules, the LC molecules above the lens areas 3304 are aligned according to the configuration of the underlying embossed alignment layer and have a systematic orientation for use as a wave plate or a wave plate lens according to the various embodiments described above, while the LC molecules formed above the blank areas 3308 do not have a systematic orientation for use as a wave plate or a wave plate lens.

[0425] Other Examples

[0426] In a first example, a display device includes a waveguide configured to guide light in a lateral direction parallel to an output surface of the waveguide. The waveguide is further configured to couple out the guided light through the output surface. The display device further includes a broadband adaptive lens assembly configured to couple in and diffract outcoupled light from the waveguide. The broadband adaptive lens assembly includes a first waveplate lens, the first waveplate lens includes a liquid crystal (LC) layer, the liquid crystal layer is arranged so that the waveplate lens has a birefringence (Δn) that varies in a direction radially outward from a central region of the first waveplate lens, and is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% within a wavelength range including at least 450nm to 630nm. The broadband adaptive lens assembly is configured to selectively switch between a plurality of states having different optical powers.

[0427] In a second example, in the display device according to the first example, Δn of the first wave plate lens increases as the wavelength (λ) in the wavelength range increases.

[0428] In a third example, in the display device according to the first example or the second example, the broadband adaptive lens assembly includes a plurality of liquid crystal layers, wherein each of the liquid crystal layers includes liquid crystal molecules continuously twisted in a layer normal direction.

[0429] In a fourth example, in a display device according to any one of the first to third examples, when the outcoupled light has polarization, the broadband adaptive lens assembly is configured to selectively switch between at least two lens states. The two lens states include: a first lens state configured to converge or diverge the outcoupled light from the waveguide according to a first optical focal length and change the polarization of the outcoupled light; and a second lens state configured to converge or diverge the outcoupled light from the waveguide according to a second optical focal length without changing the polarization of the outcoupled light.

[0430] In Example 5, in a display device according to any one of Examples 1 to 4, the broadband adaptive lens component further includes a second wave plate lens comprising a second liquid crystal layer, and a switchable wave plate between the first wave plate lens and the second wave plate lens, wherein the broadband adaptive lens component is configur...

Claims

1. An adaptive lens assembly, comprising: one or more waveplate lenses and one or more switchable waveplates aligned in the optical path, wherein each of the one or more wave plate lenses is configured to diffract outcoupled light with a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm, and to change the polarization state of light passing therethrough to provide a first optical power for light having a first polarization and a second optical power for light having a second polarization, and wherein each of the one or more switchable wave plates is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% within a wavelength range including at least 450 nm to 630 nm, and is selectively switchable between the following states: a first state configured to allow light to pass therethrough without changing the polarization state of the light; as well as A second state is configured to change the polarization state of light passing therethrough.

2. The adaptive lens assembly of claim 1, wherein one or both of the wave plate lens and the switchable wave plate comprise liquid crystal.

3. The adaptive lens assembly of claim 1, wherein each of the one or more switchable wave plates in the second state is a half-wave plate configured to invert the handedness of circularly polarized light.

4. The adaptive lens assembly of claim 1, wherein each of the switchable wave plates is interposed between a pair of the one or more wave plate lenses. 5 . The adaptive lens assembly according to claim 4 , wherein the adaptive lens assembly comprises a plurality of the wave plate lenses and a plurality of the switchable wave plates, wherein the wave plate lenses and the switchable wave plates are alternately stacked.

6. A wearable augmented reality head-mounted display system, comprising: a light modulation system configured to output light to form an image; Head mounted frame; one or more waveguides attached to the frame and configured to receive light from the light modulation system; A pair of adaptive lens assemblies, wherein the one or more waveguides are disposed between the adaptive lens assemblies, wherein each of the adaptive lens assemblies comprises: one or more wave plate lenses configured to diffract outcoupled light with a diffraction efficiency greater than 90% over a wavelength range including at least 450 nm to 630 nm and to provide a first optical power for light having a first polarization and a second optical power for light having a second polarization, and one or more switchable wave plates located in the optical path, wherein each of the one or more switchable wave plates is configured to diffract the outcoupled light with a diffraction efficiency greater than 90% in a wavelength range including at least 450 nm to 630 nm, and to selectively change the polarization state of light passing therethrough, The adaptive lens assembly is configured to provide a corresponding optical power that is adjustable when a corresponding electrical signal is applied.

7. A head mounted display system configured to project light into a user's eyes to display augmented reality image content in the user's field of view, the head mounted display system comprising: a frame configured to be supported on a head of the user; as well as an eyepiece disposed on the frame, at least a portion of the eyepiece being transparent and disposed in a position in front of the user's eyes when the user wears the head mounted display, such that the transparent portion transmits light from the environment in front of the user to the user's eyes to provide a view of the environment in front of the user, the eyepiece being configured to emit light into the user's eyes to display augmented reality image content to the user's field of view; At least one switchable lens assembly comprising a diffractive liquid crystal lens assembly, the diffractive liquid crystal lens assembly comprising a twisted nematic switchable lens, the twisted nematic switchable lens comprising: Active layer of twisted nematic liquid crystal; a first polymerized liquid crystal layer adjacent to the active layer of twisted nematic liquid crystal; a second polymerized liquid crystal layer adjacent to the active layer of twisted nematic liquid crystal, the active layer of twisted nematic liquid crystal being disposed between the first polymerized liquid crystal layer and the second polymerized liquid crystal layer; a first electrode and a second electrode configured to apply an electric field to an active layer of the twisted nematic liquid crystal, the first electrode and the second electrode being located on opposite sides of the active layer and the first and second polymerized liquid crystal layers, such that the active layer and the first and second polymerized liquid crystal layers are disposed between the first electrode and the second electrode; and an electronic device configured to change the optical power of the switchable lens by applying an electrical signal to the electrode, Wherein the at least one switchable lens assembly is configured to transmit light from the environment in front of the user to the user's eyes. The display device according to claim 7 , wherein the active layer comprises a diffractive lens.

9. The display device according to any one of claims 7 or 8, wherein the first polymerized liquid crystal layer and the second polymerized liquid crystal layer comprise diffractive lenses.

10. The display device according to any one of claims 7 to 9, wherein the first polymerized liquid crystal layer and the second polymerized liquid crystal layer are alignment layers for the active liquid crystal layer.

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