NZ794153A - Liquid crystal diffractive devices with nano-scale pattern and methods of manufacturing the same - Google Patents

Abstract

optical device, comprising: a patterned substrate comprising at least a first zone comprising a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction, wherein the first plurality of features and the second plurality of features have a dimension less than or equal to about 100 nm; and a liquid crystal layer over the patterned substrate; wherein molecules of the liquid crystal layer are self-aligned to the first and the second plurality of features. he second plurality of features have a dimension less than or equal to about 100 nm; and a liquid crystal layer over the patterned substrate; wherein molecules of the liquid crystal layer are self-aligned to the first and the second plurality of features.

Description

An optical device, comprising: a patterned substrate comprising at least a first zone comprising a first plurality of es oriented along a first direction and a second zone comprising a second plurality of features ed along a second direction, wherein the first plurality of features and the second plurality of es have a dimension less than or equal to about 100 nm; and a liquid crystal layer over the patterned substrate; wherein molecules of the liquid crystal layer are selfaligned to the first and the second plurality of features.

NZ 794153 MLEAP.062WO PATENT LIQUID CRYSTAL DIFFRACTIVE DEVICES WITH NANO-SCALE PATTERN AND S OF MANUFACTURING THE SAME Priority Claim This application claims the priority benefit of U.S. Non-Provisional Application No. 15/795,067, filed on October 26, 2017 and U.S. Provisional Patent Application No. 62/424,341 filed on November 18, 2016, both of which are incorporated by reference herein in their entireties. [0001a] This application is a divisional of New Zealand Patent Application No. 753635, the entire contents of which are incorporated herein by reference.

Incorporation by nce This application incorporates by reference the entirety of each of the following patent applications: U.S. ation No. 14/555,585 filed on November 27, 2014; U.S. Application No. 14/690,401 filed on April 18, 2015; U.S. Application No. 14/212,961 filed on March 14, 2014; U.S. Application No. 14/331,218 filed on July 14, 2014; and U.S.

Application No. 15/072,290 filed on March 16, 2016.

BACKGROUND Field The present disclosure relates to optical devices, ing l reality and augmented reality imaging and visualization systems. ption of the Related Art Modern computing and display technologies have facilitated the development of systems for so called “virtual reality” or nted reality” experiences, wherein digitally reproduced images or ns thereof are presented to a user in a manner wherein they seem to be, or may be perceived as, real. A virtual reality, or “VR”, scenario typically involves presentation of digital or virtual image information without arency to Knobbe, Martens other actual real-world visual input; an augmented reality, or “AR”, io typically involves presentation of digital or l image information as an augmentation to visualization of the actual world around the user. A mixed reality, or “MR”, io is a type of AR scenario and typically involves virtual objects that are integrated into, and responsive to, the l world. For e, in an MR scenario, AR image content may be blocked by or otherwise be perceived as interacting with objects in the real world. ing to an augmented reality scene 10 is depicted wherein a user of an AR logy sees a real-world park-like g 20 featuring people, trees, buildings in the background, and a concrete platform 30. In addition to these items, the user of the AR technology also perceives that he “sees” “virtual content” such as a robot statue 40 standing upon the real-world platform 30, and a cartoon-like avatar character 50 flying by which seems to be a personification of a bumble bee, even though these elements 40, 50 do not exist in the real world. Because the human visual perception system is x, it is challenging to produce an AR technology that facilitates a comfortable, natural-feeling, rich presentation of virtual image elements amongst other virtual or real-world imagery elements.

Systems and methods disclosed herein s various challenges related to AR and VR technology.

SUMMARY The systems, methods and devices of the disclosure each have l innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

An innovative aspect of the subject matter of this application is ed in an optical device comprising a liquid crystal layer having a first major surface, a second major surface and a thickness, the first and the second major surfaces extending across a transverse direction and the thickness extending along a direction parallel to a surface normal of the first or the second major surface, the liquid crystal layer comprising a plurality of sublayers distributed across the thickness of the liquid crystal layer, each of the plurality of sublayers comprising a single layer of liquid crystal molecules, each of the liquid crystal molecules having a longitudinal axis. Each sub-layer comprises a first domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a first Knobbe, Martens pattern; and a second domain in which the longitudinal axes of a plurality of the liquid crystal molecules are arranged to form a second pattern. The first domain is spaced apart laterally along the transverse ion from the second domain by a domain gap having a ce D between about 10 nm and about 50 nm. The longitudinal axes of the liquid crystal molecules in the domain gap progressively transition from the first pattern to the second pattern.

In various embodiments of the device, the longitudinal axes of the molecules of the first domain of a sub-layer can be twisted with respect to the longitudinal axes of the molecules of the first domain of an adjacent sub-layer. Various embodiments of the device can further comprise a second liquid crystal layer comprising, wherein liquid crystal les of the second liquid crystal layer are configured to self-align to the first direction and the second direction in first and second domains respectively. The liquid crystal layer or the second liquid l layer can comprise a rizable liquid crystal material. Various embodiments of the device can further comprise a third liquid crystal layer over the second liquid crystal layer, wherein a plurality of liquid crystal molecules of the third liquid crystal can be arranged along a third direction. Various ments of the device can further comprise a fourth liquid crystal layer over the third liquid crystal layer, n a plurality of liquid crystals of the fourth liquid crystal layer can be configured to self-align to the third direction. In various embodiments, the second liquid crystal layer and/or the fourth liquid crystal layer can be disposed over a waveguide. The second liquid crystal layer and/or the fourth liquid crystal layer can comprise in-coupling optical elements configured to in-couple an incident beam of light into the waveguide such that the incident beam of light propagates through the waveguide by total internal reflection. s ments of the device can comprise a light modulation device configured to direct light into the waveguide via the in-coupling optical elements. The second liquid crystal layer and/or the fourth liquid crystal layer can comprise out-coupling optical elements configured to out-couple an incident beam of light propagating through the waveguide by total al reflection.

In various embodiments, the second liquid crystal layer and/or the fourth liquid crystal layer can comprise orthogonal pupil ers configured to redirect light propagating through the waveguide by total internal tion, wherein the redirected light continues to propagate h the waveguide by total internal reflection. In s Knobbe, Martens embodiments of the device, the liquid crystal layer can comprise in-coupling optical elements configured to in-couple an incident beam of light into a waveguide such that an nt beam of light propagates through the waveguide by total al reflection. In various embodiments of the device, the liquid crystal layer can comprise out-coupling optical elements configured to uple beam of light propagating through a waveguide by total internal reflection. The longitudinal axes of the ity of the liquid crystal molecules in the first domain can be aligned along a first ion and the longitudinal axes of the ity of the liquid crystal molecules in the second domain can be aligned along a second direction. The longitudinal axes of the liquid crystal molecules in the domain gap can progressively transition from the first direction to the second direction.

Another innovative aspect of the subject matter of this application es a method for fabricating an optical device, the method comprising: providing a polymerizable liquid crystal layer over a substrate; patterning the polymerizable liquid crystal layer; and depositing a liquid crystal layer on the patterned polymerizable liquid crystal layer. Molecules of the deposited liquid crystal layer are ligned to the patterned polymerizable liquid crystal layer. Patterning the rizable liquid crystal layer comprises imprinting the polymerizable liquid crystal layer by an imprint template having a first domain comprising a first plurality of features and a second domain comprising a second plurality of features, the first domain spaced apart from the second domain by a region devoid of features, a dimension of the region devoid of es having a value between about 20 nm and about 100 nm. The dimension can comprise at least one of a length or a width. A width of the first plurality of features can be greater than or equal to about 20 nm and less than or equal to about 100 nm. A width of the second plurality of features can be greater than or equal to about 20 nm and less than or equal to about 100 nm. A distance between centers of two consecutive features of the first ity of features can be greater than or equal to about 20 nm and less than or equal to about 100 nm. A height of the first plurality of features can be greater than or equal to about 10 nm and less than or equal to about 100 nm. A distance n centers of two consecutive features of the second plurality of es can be greater than or equal to about 20 nm and less than or equal to about 100 nm. A height of the second plurality of features can be greater than or equal to about 10 nm and less than or equal to about 100 nm.

Knobbe, Martens The first plurality of features of the first domain can be arranged to form a first n and the second plurality of features of the second domain can be arranged to form a second pattern. The first pattern can be distinct from the second pattern. The first plurality of features can be oriented along a first direction and the second plurality of features of the second domain can be oriented along a second pattern. The first ion can be distinct from the second direction. The first plurality of features can comprise at least one of linear grooves, curvilinear grooves, linear facets or curvilinear facets. The second plurality of features can comprise at least one of linear grooves, curvilinear grooves, linear facets or curvilinear facets. The t template can comprise a semiconductor material. In various embodiments, the imprint template can be manufactured using at least one of optical lithography, nano-imprint, or ion- and on-beam lithography.

Another innovative aspect of the subject matter of this application is included in a method of manufacturing a liquid crystal device. The method comprises ting a layer of liquid crystal material on a substrate; and using an imprint template comprising a pattern to imprint a n on the layer of liquid crystal material such that molecules of the liquid crystal material are self-aligned to the pattern. The pattern comprises a first domain having a first ity of features arranged to form a first pattern and a second domain having a second ity of es arranged to form a second pattern. The first domain is spaced apart from the second domain by a region devoid of features. At least one of a width or a length of the region devoid of features is between about 20 nm and about 100 In various embodiments, the method further comprises depositing a layer of material having a tive index lower than refractive index of the liquid crystal material.

The layer of low refractive index material can be configured as a ization layer using a planarization template. The first plurality of features or the second plurality of es can include surface relief features. At least one of a length, width or height of the first plurality of features or the second plurality of features can be between about 10 nm and about 100 nm.

The first domain or the second domain can include PBPE ures. The liquid crystal device can comprise a metasurface and/or a metamaterial. The first domain or the second domain includes a grating array. In various embodiments, the first domain or the second domain can comprise curvilinear grooves or arcs.

Knobbe, Martens In various embodiments of the method, depositing a layer of liquid crystal material can include jet depositing the layer of liquid crystal material. The method further comprises depositing an onal layer of liquid crystal al over the layer of liquid crystal al. The additional layer of liquid crystal material can be self-aligned to the pattern of the layer of liquid crystal material. A pattern can be imprinted on the additional layer of liquid crystal al. The pattern imprinted on the additional layer of liquid l material can be different from the pattern imprinted on the layer of liquid crystal material. In various embodiments, the pattern imprinted on the layer of liquid crystal material can be configured to act on a first wavelength, and the pattern imprinted on the additional layer of liquid l material can be configured to act on a second wavelength.

Yet another innovative aspect of the subject matter of this application is included in a method of manufacturing a liquid crystal device. The method comprises ting a layer of polymerizable liquid crystal material on a substrate; imprinting a pattern on the polymerizable liquid crystal material using an imprint template; and ting a layer of liquid crystal material on the patterned polymerizable liquid crystal al such that molecules of the liquid crystal material are self-aligned to the pattern.

The imprint template comprises an imprint n including a first domain having a first plurality of features arranged to form a first pattern and a second domain having a second plurality of features arranged to form a second pattern. The first domain is spaced apart from the second domain by a domain gap region devoid of features. At least one of a width or a length of the domain gap region is between about 20 nm and about 100 In various embodiments of the method, depositing a layer of polymerizable liquid crystal material can include jet ting the polymerizable liquid crystal material. The first or the second plurality of features can comprise surface relief features. The first or the second ity of features can have a size between about 10 nm and about 100 nm. The first or the second domain can include PBPE structures. The liquid crystal device can comprise a metasurface and/or a metamaterial. The first or the second domain can e a grating array. The first or the second plurality of features can include curvilinear grooves or arcs. In various embodiments of the method, ting a layer of liquid crystal material can include jet depositing the layer of liquid crystal material.

Knobbe, Martens The method can r comprise ting an additional layer of liquid crystal material over the layer of liquid l material. The additional layer of liquid crystal material can be self-aligned to the pattern of the layer of liquid crystal al. A pattern can be imprinted on the additional layer of liquid crystal al. The pattern imprinted on the onal layer of liquid crystal material can be different from the pattern imprinted on the layer of liquid crystal material. The pattern imprinted on the layer of liquid crystal material can be configured to act on a first wavelength, and the pattern imprinted on the additional layer of liquid crystal material can be configured to act on a second wavelength.

Yet another innovative aspect of the subject matter of this application includes a method of manufacturing a liquid crystal device. The method comprises depositing a layer on a substrate; imprinting a pattern on the layer using an t template comprising an imprint pattern; and depositing a layer of liquid crystal material on the patterned layer such that molecules of the liquid l material are self-aligned to the pattern. The imprint pattern comprises a first domain having a first plurality of features arranged to form a first pattern and a second domain having a second plurality of features arranged to form a second pattern. The first domain is spaced apart from the second domain by a domain gap region devoid of features, and at least one of a width or a length of the domain gap region is between about 20 nm and about 100 nm.

The layer can comprise a polymerizable liquid crystal material. In various embodiments of the method, depositing a layer includes jet depositing the layer. The first or the second plurality of features can include e relief features. The first or the second plurality of features can have a size between about 10 nm and about 100 nm. The first or the second domain can include PBPE structures or a metasurface. The first or the second domain can include a grating array. The first or the second plurality of features can include curvilinear grooves or arcs. In various embodiments, depositing a layer of liquid crystal material can include jet depositing the layer of liquid crystal material.

Various embodiments of the method can further comprise depositing an additional layer of liquid l material over the layer of liquid l al. The additional layer of liquid crystal material can be self-aligned to the pattern of the layer of liquid crystal material. A pattern can be imprinted on the additional layer of liquid crystal material. The pattern imprinted on the additional layer of liquid crystal material can be Knobbe, Martens different from the pattern imprinted on the layer of liquid crystal material. The pattern imprinted on the layer of liquid crystal material can be configured to act on a first wavelength, and the pattern imprinted on the additional layer of liquid crystal material can be configured to act on a second wavelength.

Another innovative aspect of the subject matter of this application es a liquid crystal device comprising a ate; and a layer of liquid crystal material have a first surface nt the substrate and a second surface opposite the first surface. A first plurality of les of the layer of liquid crystal material on the second surface are arranged to form a first pattern and a second first plurality of molecules of the layer of liquid l material on the second surface are arranged to form a second pattern. The first plurality of molecules are spaced apart from the second plurality of molecules by a gap having a distance between about 20 nm and about 100 nm, and wherein les of the layer of liquid crystal material in the gap are arranged to progressively transition from the first pattern to the second pattern. In various embodiments, the layer of liquid crystal material is configured as a polarization g.

Another innovative aspect of the subject matter of this application includes a liquid crystal device comprising a substrate; a material have a first surface adjacent the substrate and a second surface opposite the first surface; and a liquid crystal material on the second surface of the material. The material comprises a first pattern on the second surface; and a second n on the second e. The first pattern is spaced apart from the second pattern by a gap having a distance between about 20 nm and about 100 nm. In s embodiments of the device, the material can comprise a polymerizable liquid crystal material.

An innovative aspect of the subject matter of this application is implemented in a method for fabricating a liquid crystal lens. The method comprises providing an imprint layer over a substrate. The imprint layer ses at least a first zone comprising a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction. The second direction can be rotated by an angle between about 1 degree and about 45 degrees with respect to the first direction. The method further comprises depositing a liquid l layer on the imprint layer, wherein molecules of the deposited liquid crystal layer are self-aligned , Martens to the first and the second ity of features. In various implementations, the imprint layer can comprise between about five and thirty zones. The first and the second zones can be spaced apart by a gap less than or equal to about 10 nm. For example, the first and the second zones can be spaced apart by a gap less than or equal to about 5 nm, less than or equal to about 2 nm and/or less than or equal to about 1 nm.

The first or the second plurality of features can comprise nano-features, such as, for example, grooves. A length or a width of the first plurality of features and the second plurality of features can be less than or equal to about 200 nm. For example, the length or the width of the first ity of features and the second ity of features can be less than or equal to about 100 nm. A height or a depth of the first plurality of es and the second plurality of features can be less than or equal to about 200 nm. For e, the height or the depth of the first plurality of features and the second plurality of features can be less than or equal to about 100 nm.

The imprint layer can se a semiconductor material. The liquid crystal layer can comprise a polymerizable liquid crystal material. The method further comprises polymerizing the polymerizable liquid crystal material after the molecules of the polymerizable liquid crystal material are self-aligned to the first and the second plurality of features. Polymerizing the polymerizable liquid crystal material can comprise exposing the polymerizable liquid crystal material to ultra-violet light. The liquid crystal lens can comprise a diffractive lens. Depositing a liquid l layer on the imprint layer can comprise jet depositing the liquid crystal.

An innovative aspect of the subject matter of this application is implemented in a liquid crystal lens. The liquid crystal lens comprises a patterned substrate comprising at least a first zone comprising a first plurality of features oriented along a first direction and a second zone comprising a second plurality of es oriented along a second direction. The first plurality of features and the second ity of features have a dimension less than or equal to about 100 nm. The lens comprises a liquid crystal layer over the patterned substrate, wherein molecules of the liquid l layer are self-aligned to the first and the second plurality of features. The dimension can comprise a length, a height, a depth or a width of the feature. The liquid l can comprise a polymerizable liquid crystal.

Knobbe, Martens The patterned substrate can comprise a ate having a layer disposed thereon that is patterned. The first and the second zones can comprise concentric ring-shaped zones. The lens can comprise between about 3 and 30 zones. For example, the lens can comprise at least five zones. A width of the zones can ssively decrease with distance from a center of the patterned substrate. In various entations, the zones can have no gap therebetween. In some implementations, a gap between the zones can be less than or equal to 5 nm. For e, the gap between the zones can be less than or equal to 1 nm.

The lens can be configured as a diffractive lens. The lens can be configured to provide positive or negative optical power.

Various embodiments of the liquid crystal devices bed herein can be included with a waveguide of a display system. The embodiments of the liquid crystal devices described herein can be configured to selectively ple at least one light stream from a multiplexed light stream into the waveguide and transmit one or more other light streams from the multiplexed light . Various embodiments of the liquid crystal device described herein can be included with an eyepiece of a head mounted display. [0030A] In one broad form, an aspect of the present ion seeks to provide an optical device, comprising: a patterned substrate comprising at least a first zone comprising a first plurality of features oriented along a first ion and a second zone comprising a second plurality of features oriented along a second direction, wherein the first plurality of features and the second plurality of features have a dimension less than or equal to about 100 nm; and a liquid crystal layer over the patterned substrate; wherein molecules of the liquid crystal layer are self-aligned to the first and the second plurality of features. [0030B] In one embodiment the patterned substrate comprises a substrate having a layer disposed thereon that is patterned. [0030C] In one embodiment the at least first and second zones se tric ring-shaped zones. [0030D] In one embodiment the optical device comprises at least five zones. [0030E] In one embodiment a width of the zones ssively decrease with distance from a center of the patterned substrate.

Knobbe, Martens [0030F] In one embodiment the zones have no gap therebetween. [0030G] In one embodiment a gap between the zones is less than or equal to 1 nm. [0030H] In one embodiment a gap between the zones is less than or equal to 5 nm. [0030I] In one embodiment the dimension comprise a length or width of the feature. [0030J] In one embodiment the liquid crystal comprises polymerized liquid crystal. [0030K] In one embodiment the optical device comprises a diffractive lens. [0030L] In one embodiment the optical device is configured to provide optical power. [0030M] In one embodiment: the patterned ate comprises a substrate upon which a material is disposed, the material has a first surface adjacent the substrate and a second surface opposite the first surface, the material comprises: the first zone arranged to form a first pattern on the second surface, and the second zone arranged to form a second pattern on the second surface, the first pattern is spaced apart from the second n by a gap having a distance between about 20 nm and about 100 nm, and the liquid l layer is on the second surface of the material. [0030N] In one embodiment the material comprises a polymerizable liquid crystal material. [0030O] In one embodiment the optical device is included with an eyepiece of a head mounted display. [0030P] In one embodiment the optical device is configured to ively incouple at least one light stream from a lexed light stream into a waveguide of the eyepiece and transmit one or more other light streams from the multiplexed light . [0030Q] In one broad form an aspect of the present invention seeks to provide a method for fabricating an l device, the method comprising: , Martens providing an imprint layer over a substrate, the imprint layer comprising at least a first zone sing a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction; and depositing a liquid crystal layer on the imprint layer; wherein molecules of the deposited liquid crystal layer are self-aligned to the first and the second plurality of features. [0030R] In one embodiment the first and the second zones are spaced apart by a gap less than or equal to about 5 nm. [0030S] In one embodiment the first or the second plurality of features comprise grooves. [0030T] In one embodiment the second direction is rotated by an angle n about 1 degree and about 45 degrees with respect to the first direction. [0030U] In one ment the imprint layer comprises a semiconductor material. [0030V] In one embodiment the liquid crystal layer ses a polymerizable liquid crystal material. [0030W] In one embodiment the method further comprises polymerizing the polymerizable liquid crystal material after the molecules of the polymerizable liquid crystal material are ligned to the first and the second plurality of features. [0030X] In one embodiment polymerizing the polymerizable liquid crystal al comprises ng the polymerizable liquid crystal material to violet light. [0030Y] In one embodiment the lens comprises a ctive lens. [0030Z] In one embodiment depositing a liquid crystal layer on the imprint layer comprises jet depositing the liquid crystal. [0030ZA] In one ment a length or a width of the first plurality of features and the second plurality of features is less than or equal to about 100 nm. [0030ZB] In one embodiment a height or a depth of the first plurality of features and the second plurality of features is less than or equal to about 100 nm.

Details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, the drawings, Knobbe, Martens and the claims. Note that the relative dimensions of the ing figures may not be drawn to scale.

BRIEF DESCRIPTION OF THE DRAWINGS illustrates a user’s view of augmented reality (AR) through an AR device. illustrates an example of a wearable y system. illustrates a conventional display system for simulating threedimensional imagery for a user. illustrates aspects of an approach for simulating three-dimensional imagery using multiple depth planes.

FIGS. 5A-5C illustrate relationships between radius of ure and focal radius. illustrates an example of a waveguide stack for outputting image information to a user. rates an example of exit beams outputted by a waveguide. illustrates an example of a stacked waveguide assembly in which each depth plane includes images formed using multiple different component colors. illustrates a cross-sectional side view of an example of a set of stacked waveguides that each includes an in-coupling optical element. illustrates a perspective view of an example of the plurality of stacked waveguides of . illustrates a top-down plan view of an example of the plurality of stacked waveguides of FIGS. 9A and 9B.

A illustrates a top view of an example of a liquid l layer comprising a plurality of domains of liquid crystal molecules. B illustrates a magnified top view of the liquid crystal layer ed in A showing the orientation of the liquid crystal molecules in each domain. FIGS. 10C, 10D, 10E and 10F illustrate side views of various embodiment of the liquid l layer ed in A.

A illustrates a top view of an imprint template including a ity surface features configured to manufacture the liquid crystal layer depicted in A.

Knobbe, Martens B illustrates a side view of the imprint template ed in FIG.

FIGS. 12A-12D illustrate an embodiment of a method of manufacturing a liquid crystal layer ing a plurality of liquid crystal molecules arranged in different patterns. E illustrates an embodiment of a stacked liquid crystal device comprising a plurality of liquid crystal layers.

A rates a scanning electron microscope (SEM) image of an embodiment of an imprint template. B is a SEM image of a patterned PLC layer ctured using the imprint te of A and the method discussed above with reference to FIGS. C. C is a polarizing microscope image of the patterned PLC layer shown in B. illustrates an embodiment of an electrically-controllable liquid crystal device.

FIGS. 15A-15C illustrate an example of a method of manufacturing various liquid crystal devices described herein.

A illustrates a top view of an implementation of a diffractive lens comprising a liquid crystal material.

B illustrates a copic image of an implementation of the lens between crossed polarizers. FIGS. 16B-1 and 16B-2 depict a scanning electron microscope (SEM) image showing the pattern of the imprint layer that achieves the desired alignment of the longitudinal axes in s regions of the liquid crystal lens.

FIGS. 17A-17C illustrate an example of a method of manufacturing a liquid crystal lens A illustrates a ng electron microscope (SEM) image of an imprint layer that is used to manufacture an implementation of a liquid crystal lens. B illustrates a scanning electron microscope (SEM) image of a liquid crystal layer disposed over the imprint layer of A.

Like reference numbers and designations in the various drawings indicate like ts.

Knobbe, Martens DETAILED PTION Liquid ls (LCs) comprise liquid crystal molecules having a longitudinal axis which is arbitrarily oriented under certain conditions. However, under certain other conditions, the LC molecules can be ordered such that the longitudinal axes are oriented along an average direction (referred to herein as the director). Some liquid crystal molecules can be symmetric about the longitudinal axis. LCs are an anisotropic material that can have different optical properties for different wavelengths or polarizations of light depending on the ion of propagation of light through the LC and the polarization of light with respect to the ion along which the LC molecules are generally oriented. For example, LC molecules exhibit birefringence in which light polarized along a direction of the general orientation of the longitudinal axes of LC les has a tive index different from the tive index of light zed a ion perpendicular to the general orientation of the longitudinal axes of LC molecules. As a result of birefringent nature of LC materials, they are widely used in various systems include displays, optical communications, optical data storage, sensors, etc. The refractive index of a LC material can be varied by varying the orientation of the longitudinal axes of the molecules of the LC material.

Accordingly, LC materials can be configured as phase gratings. LC grating structures can be used to selectively diffract light along different directions based on wavelength and/or polarization.

One way of fabricating LC grating structures includes a mechanical method such as a rubbing process in which surface features are produced on an alignment layer (e.g., a r) by rubbing or a scratching the surface of the alignment layer using a mechanical object (e.g., a metal object, cloth, tip of an atomic force cope, etc.). The molecules of a layer LC material deposited on the alignment layer are aligned to e features on the alignment layer to form a grating pattern. However, the g process can cause mechanical damage to the e of the alignment layer and/or introduce electrostatic charges or impurities on the surface of the alignment layer which can reduce the diffraction efficiency of the liquid crystal grating structure. Furthermore, it may not be practical to fabricate complex grating structures (e.g., LC gs comprising patterns with different orientations of LC molecules) using the rubbing method. Additionally, it may not be practical to fabricate space-variant nano-scale patterns of liquid crystal materials that can be Knobbe, Martens used to manipulate phase, amplitude and/or polarization of incident light. In contrast, various implementations described herein can be used to fabricate space-variant nano-scale patterns of liquid crystal materials that can be used to manipulate phase, amplitude and/or polarization of incident light. Some embodiments of a liquid crystal material with space-variant nanoscale pattern can include a liquid crystal rface. Other embodiments of a liquid l al with space-variant nano-scale pattern can include a liquid crystal comprising a ity of nt domains, wherein the liquid crystal molecules in each domain can be arranged to form a nano-scale pattern.

In some embodiments, the LC grating structures may be utilized as tuent parts of a display . The display system may include a waveguide, and an image injection device configured to direct a light beam into the waveguide. The LC grating ures may be used as one or more of an in-coupling optical element, an out-coupling optical t, and an optical element for ing incident light propagating in the waveguide and for redirecting that incident light so that the redirected light continues to ate through the waveguide by total internal reflection. Examples of the latter type of optical element include pupil expanders such as orthogonal pupil expanders (OPEs).

In some embodiments, the LC grating structures may be used to in-couple, out-couple, and/or redirect light propagating within the waveguide. The light may be light of a single wavelength or a single range of wavelengths. In some other embodiments, the light may be a light stream that is part of a lexed light stream that includes a plurality of light streams having different light properties (e.g., each stream may have a different wavelength). For example, the waveguide may include the LC grating structures, which may be configured to selectively ct a light beam formed of light having a particular light property (e.g., a first ngth), while being substantially transmissive to one or more other streams of light (e.g., having wavelengths different from the first wavelength). In some embodiments, the waveguide is part of a stack of waveguides, which can include a second waveguide including in-coupling optical elements configured to selectively turn a second of the streams of light while being transmissive to one or more other streams of light. In some embodiments, the in-coupling LC grating structures of the waveguide are configured to transmit at least one of the streams of light to the in-coupling LC grating structures of the second waveguide.

Knobbe, Martens Reference will now be made to the figures, in which like reference numerals refer to like parts throughout. It will be appreciated that embodiments disclosed herein include optical systems, including display systems, generally. In some embodiments, the display systems are wearable, which may advantageously provide a more ive VR or AR experience. For example, displays ning one or more waveguides (e.g., a stack of waveguides) may be configured to be worn positioned in front of the eyes of a user, wearer and/or viewer. In some embodiments, two stacks of waveguides, one for each eye of a viewer, may be utilized to provide different images to each eye.

Example Display s rates an example of le display system 60. The display system 60 includes a display 70, and various mechanical and electronic modules and systems to support the oning of that y 70. The display 70 may be coupled to a frame 80, which is wearable by a display system user or viewer 90 and which is configured to position the display 70 in front of the eyes of the user 90. The display 70 may be considered eyewear in some embodiments. In some embodiments, a speaker 100 is coupled to the frame 80 and configured to be positioned nt the ear canal of the user 90 (in some embodiments, another speaker, not shown, is positioned adjacent the other ear canal of the user to provide stereo/shapeable sound control). In some embodiments, the display system may also include one or more microphones 110 or other devices to detect sound. In some ments, the microphone is configured to allow the user to provide inputs or commands to the system 60 (e.g., the selection of voice menu commands, natural language questions, etc.), and/or may allow audio communication with other persons (e.g., with other users of r display systems. The microphone may further be configured as a peripheral sensor to collect audio data (e.g., sounds from the user and/or environment). In some embodiments, the display system may also include a peripheral sensor 120a, which may be separate from the frame 80 and attached to the body of the user 90 (e.g., on the head, torso, an extremity, etc. of the user 90). The eral sensor 120a may be configured to acquire data characterizing the physiological state of the user 90 in some embodiments. For e, the sensor 120a may be an electrode.

Knobbe, Martens With continued reference to the display 70 is operatively coupled by communications link 130, such as by a wired lead or wireless connectivity, to a local data processing module 140 which may be mounted in a variety of configurations, such as fixedly attached to the frame 80, fixedly attached to a helmet or hat worn by the user, embedded in headphones, or otherwise removably attached to the user 90 (e.g., in a backpack-style configuration, in a belt-coupling style configuration). rly, the sensor 120a may be operatively coupled by communications link 120b, e.g., a wired lead or wireless connectivity, to the local processor and data module 140. The local sing and data module 140 may comprise a re processor, as well as digital memory, such as non-volatile memory (e.g., flash memory or hard disk drives), both of which may be ed to assist in the processing, caching, and storage of data. The data include data a) captured from sensors (which may be, e.g., operatively coupled to the frame 80 or ise attached to the user 90), such as image capture devices (such as cameras), hones, inertial measurement units, accelerometers, compasses, GPS units, radio devices, gyros, and/or other sensors sed herein; and/or b) acquired and/or processed using remote processing module 150 and/or remote data tory 160 (including data relating to virtual content), possibly for passage to the display 70 after such processing or retrieval. The local processing and data module 140 may be operatively coupled by communication links 170, 180, such as via a wired or wireless communication links, to the remote processing module 150 and remote data repository 160 such that these remote modules 150, 160 are operatively coupled to each other and available as resources to the local processing and data module 140. In some embodiments, the local processing and data module 140 may e one or more of the image capture devices, hones, inertial measurement units, rometers, compasses, GPS units, radio devices, and/or gyros. In some other embodiments, one or more of these sensors may be attached to the frame 80, or may be standalone structures that communicate with the local processing and data module 140 by wired or wireless ication pathways.

With continued reference to in some embodiments, the remote processing module 150 may comprise one or more processors configured to analyze and process data and/or image information. In some embodiments, the remote data repository 160 may se a digital data storage facility, which may be available through the internet Knobbe, Martens or other networking configuration in a “cloud” ce configuration. In some embodiments, the remote data repository 160 may include one or more remote servers, which provide information, e.g., information for generating augmented reality content, to the local processing and data module 140 and/or the remote sing module 150. In some embodiments, all data is stored and all computations are med in the local processing and data , ng fully autonomous use from a remote module.

The perception of an image as being “three-dimensional” or “3-D” may be ed by providing ly different presentations of the image to each eye of the viewer. illustrates a conventional display system for simulating three-dimensional imagery for a user. Two distinct images 190, 200—one for each eye 210, 220—are outputted to the user.

The images 190, 200 are spaced from the eyes 210, 220 by a distance 230 along an optical or z-axis that is parallel to the line of sight of the viewer. The images 190, 200 are flat and the eyes 210, 220 may focus on the images by assuming a single accommodated state. Such 3-D display systems rely on the human visual system to combine the images 190, 200 to provide a tion of depth and/or scale for the combined image.

It will be iated, however, that the human visual system is more complicated and providing a realistic perception of depth is more challenging. For example, many viewers of conventional “3-D” display systems find such systems to be uncomfortable or may not perceive a sense of depth at all. Without being limited by theory, it is believed that viewers of an object may perceive the object as being “three-dimensional” due to a ation of vergence and accommodation. Vergence movements (i.e., rotation of the eyes so that the pupils move toward or away from each other to converge the lines of sight of the eyes to fixate upon an object) of the two eyes relative to each other are closely associated with focusing (or “accommodation”) of the lenses and pupils of the eyes. Under normal conditions, changing the focus of the lenses of the eyes, or accommodating the eyes, to change focus from one object to another object at a different distance will automatically cause a matching change in ce to the same distance, under a relationship known as the “accommodation-vergence reflex,” as well as pupil dilation or constriction. Likewise, a change in vergence will trigger a ng change in accommodation of lens shape and pupil size, under normal conditions. As noted herein, many stereoscopic or “3-D” display systems display a scene using slightly different presentations (and, so, slightly different images) to Knobbe, Martens each eye such that a three-dimensional perspective is ved by the human visual system.

Such s are uncomfortable for many viewers, however, since they, among other things, simply provide a different presentation of a scene, but with the eyes g all the image information at a single odated state, and work against the “accommodation-vergence reflex.” Display systems that provide a better match between accommodation and vergence may form more realistic and comfortable simulations of three-dimensional imagery contributing to increased duration of wear and in turn compliance to diagnostic and therapy protocols. illustrates aspects of an ch for simulating three-dimensional imagery using multiple depth planes. With reference to objects at various distances from eyes 210, 220 on the z-axis are accommodated by the eyes 210, 220 so that those objects are in focus. The eyes 210, 220 assume particular accommodated states to bring into focus objects at different distances along the z-axis. Consequently, a particular accommodated state may be said to be associated with a particular one of depth planes 240, with has an associated focal distance, such that objects or parts of objects in a particular depth plane are in focus when the eye is in the accommodated state for that depth plane. In some embodiments, three-dimensional imagery may be simulated by providing ent presentations of an image for each of the eyes 210, 220, and also by providing different presentations of the image corresponding to each of the depth planes. While shown as being separate for clarity of illustration, it will be appreciated that the fields of view of the eyes 210, 220 may overlap, for example, as ce along the z-axis increases. In addition, while shown as flat for ease of illustration, it will be iated that the contours of a depth plane may be curved in physical space, such that all features in a depth plane are in focus with the eye in a particular accommodated state.

The distance between an object and the eye 210 or 220 may also change the amount of divergence of light from that object, as viewed by that eye. FIGS. 5A-5C illustrate relationships between distance and the divergence of light rays. The distance between the object and the eye 210 is represented by, in order of decreasing ce, R1, R2, and R3. As shown in FIGS. 5A-5C, the light rays become more divergent as ce to the object decreases. As distance ses, the light rays become more collimated. Stated another way, it may be said that the light field produced by a point (the object or a part of the Knobbe, Martens ) has a spherical wavefront curvature, which is a on of how far away the point is from the eye of the user. The curvature increases with decreasing distance between the object and the eye 210. Consequently, at different depth planes, the degree of divergence of light rays is also different, with the degree of divergence increasing with decreasing distance between depth planes and the viewer’s eye 210. While only a single eye 210 is illustrated for clarity of ration in FIGS. 5A-5C and other figures herein, it will be appreciated that the sions regarding eye 210 may be applied to both eyes 210 and 220 of a viewer.

Without being limited by theory, it is believed that the human eye lly can interpret a finite number of depth planes to provide depth perception.

Consequently, a highly believable simulation of perceived depth may be achieved by providing, to the eye, different presentations of an image corresponding to each of these limited number of depth planes. The ent presentations may be separately focused by the ’s eyes, thereby helping to provide the user with depth cues based on the odation of the eye required to bring into focus different image es for the scene located on different depth plane and/or based on observing different image features on different depth planes being out of focus. illustrates an example of a ide stack for outputting image information to a user. A display system 250 includes a stack of waveguides, or d waveguide assembly, 260 that may be utilized to provide three-dimensional perception to the eye/brain using a plurality of waveguides 270, 280, 290, 300, 310. In some embodiments, the display system 250 is the system 60 of with schematically showing some parts of that system 60 in greater detail. For example, the waveguide assembly 260 may be part of the y 70 of It will be appreciated that the display system 250 may be considered a light field display in some embodiments.

With continued reference to 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 with various levels of wavefront curvature or light ray divergence. Each waveguide level may be associated with a particular depth plane and may be configured to output image information corresponding to that depth plane. Image Knobbe, Martens injection devices 360, 370, 380, 390, 400 may function as a source of light for the waveguides and may be utilized to inject image information into the waveguides 270, 280, 290, 300, 310, each of which may be configured, as described herein, to bute incoming light across each tive waveguide, for output toward the eye 210. Light exits an output surface 410, 420, 430, 440, 450 of the image injection devices 360, 370, 380, 390, 400 and is ed into a corresponding input surface 460, 470, 480, 490, 500 of the waveguides 270, 280, 290, 300, 310. In some embodiments, the each of the input surfaces 460, 470, 480, 490, 500 may be an edge of a corresponding waveguide, or may be part of a major surface of the corresponding waveguide (that is, one of the waveguide es directly facing the world 510 or the viewer’s eye 210). In some embodiments, a single beam of light (e.g. a collimated beam) may be injected into each waveguide to output an entire field of cloned collimated beams that are directed toward the eye 210 at particular angles (and amounts of divergence) corresponding to the depth plane associated with a particular waveguide. In some embodiments, a single one of the image injection devices 360, 370, 380, 390, 400 may be associated with and inject light into a plurality (e.g., three) of the waveguides 270, 280, 290, 300, 310.

In some embodiments, the image injection devices 360, 370, 380, 390, 400 are discrete ys that each e image information for injection into a corresponding waveguide 270, 280, 290, 300, 310, respectively. In some other embodiments, the image injection devices 360, 370, 380, 390, 400 are the output ends of a single multiplexed display which may, e.g., pipe image information via one or more optical conduits (such as fiber optic cables) to each of the image injection devices 360, 370, 380, 390, 400. It will be appreciated that the image information provided by the image ion s 360, 370, 380, 390, 400 may include light of different wavelengths, or colors (e.g., different component colors, as discussed herein).

In some embodiments, the light injected into the waveguides 270, 280, 290, 300, 310 is provided by a light projector system 520, which ses a light module 530, which may include a light emitter, such as a light emitting diode (LED). The light from the light module 530 may be directed to and modified by a light modulator 540, e.g., a spatial light modulator, via a beam splitter 550. The light modulator 540 may be configured to change the perceived intensity of the light injected into the waveguides 270, 280, 290, 300, Knobbe, Martens 310. Examples of l light modulators include liquid crystal displays (LCD) including a liquid crystal on silicon (LCOS) displays.

In some embodiments, the display system 250 may be a scanning fiber y comprising one or more ng fibers configured to project light in various patterns (e.g., raster scan, spiral scan, Lissajous patterns, etc.) into one or more ides 270, 280, 290, 300, 310 and ultimately to the eye 210 of the viewer. In some embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may schematically represent a single scanning fiber or a bundle of scanning fibers configured to inject light into one or a plurality of the waveguides 270, 280, 290, 300, 310. In some other embodiments, the illustrated image injection devices 360, 370, 380, 390, 400 may schematically represent a plurality of scanning fibers or a ity of bundles of scanning fibers, each of which are configured to inject light into an associated one of the waveguides 270, 280, 290, 300, 310.

It will be appreciated that one or more l fibers may be configured to transmit light from the light module 530 to the one or more waveguides 270, 280, 290, 300, 310. It will be appreciated that one or more intervening optical structures may be provided between the scanning fiber, or fibers, and the one or more waveguides 270, 280, 290, 300, 310 to, e.g., redirect light exiting the scanning fiber into the one or more waveguides 270, 280, 290, 300, A controller 560 controls the operation of one or more of the stacked waveguide assembly 260, including operation of the image ion devices 360, 370, 380, 390, 400, the light source 530, and the light tor 540. In some embodiments, the controller 560 is part of the local data processing module 140. The controller 560 includes mming (e.g., instructions in a non-transitory medium) that regulates the timing and provision of image ation to the waveguides 270, 280, 290, 300, 310 according to, e.g., any of the various schemes disclosed herein. In some embodiments, the controller may be a single al device, or a distributed system connected by wired or wireless communication channels. The controller 560 may be part of the processing modules 140 or 150 ( in some embodiments.

With continued reference to the waveguides 270, 280, 290, 300, 310 may be configured to propagate light within each tive waveguide by total internal reflection (TIR). The waveguides 270, 280, 290, 300, 310 may each be planar or have Knobbe, Martens r shape (e.g., curved), with major top and bottom es and edges extending between those major top and bottom es. In the illustrated configuration, the waveguides 270, 280, 290, 300, 310 may each include out-coupling optical elements 570, 580, 590, 600, 610 that are configured to extract light out of a waveguide by redirecting the light, propagating within each respective waveguide, out of the waveguide to output image information to the eye 210. Extracted light may also be referred to as upled light and the out-coupling optical elements light may also be referred to light extracting optical elements. An extracted beam of light may be outputted by the waveguide at locations at which the light propagating in the waveguide strikes a light ting optical element. The out-coupling optical elements 570, 580, 590, 600, 610 may, for e, be gratings, including diffractive optical features, as discussed further herein. While illustrated disposed at the bottom major surfaces of the waveguides 270, 280, 290, 300, 310, for ease of description and drawing clarity, in some embodiments, the out-coupling optical elements 570, 580, 590, 600, 610 may be disposed at the top and/or bottom major surfaces, and/or may be ed directly in the volume of the waveguides 270, 280, 290, 300, 310, as discussed further herein. In some ments, the out-coupling optical elements 570, 580, 590, 600, 610 may be formed in a layer of material that is attached to a arent substrate to form the waveguides 270, 280, 290, 300, 310. In some other embodiments, the waveguides 270, 280, 290, 300, 310 may be a monolithic piece of material and the out-coupling optical ts 570, 580, 590, 600, 610 may be formed on a surface and/or in the interior of that piece of material.

With continued reference to as discussed , 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 nearest the eye may be configured to deliver collimated light (which was injected into such waveguide 270), to the eye 210.

The collimated light may be representative of the optical infinity focal plane. The next waveguide up 280 may be configured to send out collimated light which passes through the first lens 350 (e.g., a negative lens) before it can reach the eye 210; such first lens 350 may be configured to create a slight convex wavefront curvature so that the eye/brain interprets light coming from that next waveguide up 280 as coming from a first focal plane closer inward toward the eye 210 from optical infinity. Similarly, the third up waveguide 290 Knobbe, Martens passes its output light through both the first 350 and second 340 lenses before ng the eye 210; the combined optical power of the first 350 and second 340 lenses may be configured to create another incremental amount of wavefront curvature so that the eye/brain interprets light coming from the third waveguide 290 as coming from a second focal plane that is even closer inward toward the person from l infinity than was light from the next waveguide up 280.

The other waveguide layers 300, 310 and lenses 330, 320 are similarly configured, with the highest waveguide 310 in the stack sending its output through all of the lenses between it and the eye for an ate focal power representative of the closest focal plane to the . To compensate for the stack of lenses 320, 330, 340, 350 when viewing/interpreting light coming from the world 510 on the other side of the stacked waveguide assembly 260, a compensating lens layer 620 may be disposed at the top of the stack to compensate for the aggregate power of the lens stack 320, 330, 340, 350 below.

Such a uration provides as many perceived focal planes as there are ble waveguide/lens pairings. Both the out-coupling optical elements of the waveguides and the focusing aspects of the lenses may be static (i.e., not c or electro-active). In some alternative embodiments, either or both may be dynamic using electro-active features.

In some embodiments, two or more of the waveguides 270, 280, 290, 300, 310 may have the same associated depth plane. For example, multiple waveguides 270, 280, 290, 300, 310 may be configured to output images set to the same depth plane, or multiple subsets of the waveguides 270, 280, 290, 300, 310 may be configured to output images set to the same plurality of depth planes, with one set for each depth plane. This can provide advantages for forming a tiled image to provide an expanded field of view at those depth planes.

With continued reference to the out-coupling optical elements 570, 580, 590, 600, 610 may be configured to both redirect light out of their respective ides and to output this light with the appropriate amount of divergence or collimation for a particular depth plane ated with the waveguide. As a result, waveguides having different ated depth planes may have different configurations of out-coupling optical elements 570, 580, 590, 600, 610, which output light with a different amount of divergence depending on the associated depth plane. In some embodiments, the light extracting optical Knobbe, Martens elements 570, 580, 590, 600, 610 may be volumetric or surface features, which may be configured to output light at specific angles. For example, the light extracting optical elements 570, 580, 590, 600, 610 may be volume holograms, surface holograms, and/or diffraction gs. In some embodiments, the features 320, 330, 340, 350 may not be ; rather, they may simply be spacers (e.g., ng layers and/or structures for forming air gaps).

In some embodiments, the out-coupling optical elements 570, 580, 590, 600, 610 are diffractive features that form a diffraction pattern, or “diffractive optical t” (also referred to herein as a “DOE”). Preferably, the DOE’s have a sufficiently low diffraction efficiency so that only a portion of the light of the beam is deflected away toward the eye 210 with each intersection of the DOE, while the rest continues to move through a waveguide via TIR. The light carrying the image ation is thus d into a number of related exit beams that exit the waveguide at a multiplicity of locations and the result is a fairly uniform pattern of exit emission toward the eye 210 for this particular collimated beam bouncing around within a waveguide.

In some embodiments, one or more DOEs may be switchable between “on” states in which they actively diffract, and “off” states in which they do not significantly diffract. For instance, a able DOE may comprise a layer of polymer dispersed liquid crystal, in which microdroplets comprise a diffraction n in a host medium, and the refractive index of the microdroplets may be switched to substantially match the refractive index of the host material (in which case the pattern does not appreciably ct incident light) or the microdroplet may be switched to an index that does not match that of the host medium (in which case the pattern actively cts incident light).

In some embodiments, a camera ly 630 (e.g., a digital camera, including visible light and infrared light cameras) may be provided to capture images of the eye 210 and/or tissue around the eye 210 to, e.g., detect user inputs and/or to monitor the physiological state of the user. As used herein, a camera may be any image capture device.

In some ments, 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 ( and may be in electrical Knobbe, Martens communication with the sing modules 140 and/or 150, which may process image information from the camera assembly 630 to make various determinations regarding, e.g., the physiological state of the user, as discussed herein. It will be appreciated that information regarding the physiological state of user may be used to determine the behavioral or emotional state of the user. Examples of such information include movements of the user and/or facial expressions of the user. The behavioral or emotional state of the user may then be triangulated with ted environmental and/or virtual content data so as to determine relationships between the oral or nal state, physiological state, and environmental or virtual content data. In some embodiments, one camera assembly 630 may be ed for each eye, to separately monitor each eye.

With reference now to an example of exit beams outputted by a waveguide is shown. One waveguide is illustrated, but it will be appreciated that other waveguides in the waveguide assembly 260 ( may function similarly, where 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 points where the light 640 impinges on the DOE 570, a portion of the light exits the ide as exit beams 650. The exit beams 650 are illustrated as substantially parallel but, as discussed herein, they may also be redirected to propagate to the eye 210 at an angle (e.g., forming ent exit beams), depending on the depth plane associated with the waveguide 270. It will be appreciated that ntially parallel exit beams may be indicative of a waveguide with out-coupling optical elements that out-couple light to form images that appear to be set on a depth plane at a large distance (e.g., optical ty) from the eye 210. Other waveguides or other sets of out-coupling optical elements may output an exit beam pattern that is more divergent, which would require the eye 210 to accommodate to a closer distance to bring it into focus on the retina and would be interpreted by the brain as light from a distance closer to the eye 210 than optical infinity.

In some embodiments, a full color image may be formed at each depth plane by ying images in each of the component colors, e.g., three or more component colors. illustrates an example of a stacked ide ly in which each depth plane includes images formed using multiple ent component colors. The illustrated embodiment shows depth planes 240a – 240f, although more or fewer depths are also Knobbe, Martens contemplated. Each depth plane may have three or more component color images associated with it, including: a first image of a first color, G; a second image of a second color, R; and a third image of a third color, B. Different depth planes are indicated in the figure by different numbers for diopters (dpt) following the letters G, R, and B. Just as examples, the numbers following each of these letters indicate diopters (1/m), or inverse distance of the depth plane from a viewer, and each box in the figures represents an individual ent color image.

In some embodiments, to account for ences in the eye’s focusing of light of ent wavelengths, the exact placement of the depth planes for ent ent colors may vary. For example, different component color images for 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 decrease chromatic aberrations.

In some embodiments, light of each component color may be outputted by a single dedicated waveguide and, consequently, each depth plane may have multiple waveguides associated with it. In such embodiments, each box in the figures including the letters G, R, or B may be understood to represent an dual waveguide, and three waveguides may be provided per depth plane where three component color images are provided per depth plane. While the waveguides associated with each depth plane are shown adjacent to one another in this drawing for ease of description, it will be appreciated that, in a physical device, the waveguides may all be arranged in a stack with one waveguide per level.

In some other embodiments, multiple component colors may be outputted by the same ide, such that, e.g., only a single waveguide may be provided per depth plane.

With continued reference to in some embodiments, G is the color green, R is the color red, and B is the color blue. In some other embodiments, other colors associated with other wavelengths of light, ing magenta and cyan, may be used in addition to or may replace one or more of red, green, or blue. In some embodiments, features 320, 330, 340, and 350 may be active or passive optical filters configured to block or selectively light from the ambient environment to the viewer’s eyes.

It will be appreciated that references to a given color of light throughout this sure will be understood to encompass light of one or more wavelengths within a range of wavelengths of light that are perceived by a viewer as being of that given color. For example, red light may e light of one or more ngths in the range of about 620– Knobbe, Martens 780 nm, green light may include light of one or more wavelengths in the range of about 492– 577 nm, and blue light may include light of one or more wavelengths in the range of about 3 nm.

In some embodiments, the light source 530 ( may be configured to emit light of one or more wavelengths outside the visual perception range of the viewer, for example, infrared and/or ultraviolet wavelengths. In on, the pling, out-coupling, and other light redirecting structures of the waveguides of the display 250 may be configured to direct and emit this light out of the display towards the user’s eye 210, e.g., for imaging and/or user stimulation ations.

With reference now to , in some embodiments, light impinging on a waveguide may need to be redirected to in-couple that light into the ide. An incoupling optical element may be used to redirect and in-couple the light into its corresponding waveguide. illustrates a cross-sectional side view of an example of a plurality or set 660 of stacked waveguides that each includes an in-coupling optical element.

The ides may each be configured to output light of one or more different ngths, or one or more different ranges of wavelengths. It will be appreciated that the stack 660 may pond to the stack 260 ( and the illustrated waveguides of the stack 660 may correspond to part of the plurality of waveguides 270, 280, 290, 300, 310, except that light from one or more of the image injection devices 360, 370, 380, 390, 400 is injected into the ides from a position that requires light to be redirected for ling.

The illustrated set 660 of stacked waveguides includes waveguides 670, 680, and 690. Each waveguide includes an associated in-coupling optical element (which may also be referred to as a light input area on the waveguide), with, e.g., in-coupling optical element 700 disposed on a major surface (e.g., an upper major surface) of waveguide 670, incoupling optical element 710 disposed on a major surface (e.g., an upper major surface) of waveguide 680, and pling optical t 720 disposed on a major surface (e.g., an upper major surface) of waveguide 690. In some embodiments, one or more of the incoupling optical elements 700, 710, 720 may be disposed on the bottom major surface of the respective waveguide 670, 680, 690 (particularly where the one or more in-coupling optical elements are reflective, deflecting optical elements). As illustrated, the in-coupling optical Knobbe, Martens elements 700, 710, 720 may be disposed on the upper major surface of their respective waveguide 670, 680, 690 (or the top of the next lower waveguide), particularly where those in-coupling l elements are transmissive, deflecting optical elements. In some embodiments, the in-coupling optical ts 700, 710, 720 may be disposed in the body of the respective waveguide 670, 680, 690. In some embodiments, as discussed herein, the incoupling l elements 700, 710, 720 are wavelength selective, such that they ively redirect one or more wavelengths of light, while transmitting other wavelengths of light.

While illustrated on one side or corner of their tive waveguide 670, 680, 690, it will be appreciated that the in-coupling optical elements 700, 710, 720 may be disposed in other areas of their respective waveguide 670, 680, 690 in some embodiments.

As illustrated, the in-coupling optical elements 700, 710, 720 may be laterally offset from one another. In some embodiments, each in-coupling l element may be offset such that it receives light without that light passing through another incoupling optical element. For example, each in-coupling optical element 700, 710, 720 may be ured to receive light from a different image injection device 360, 370, 380, 390, and 400 as shown in and may be ted (e.g., laterally spaced apart) from other incoupling optical elements 700, 710, 720 such that it substantially does not receive light from the other ones of the in-coupling optical elements 700, 710, 720.

Each waveguide also includes associated light distributing elements, with, e.g., light distributing elements 730 disposed on a major surface (e.g., a top major surface) of waveguide 670, light distributing elements 740 disposed on a major surface (e.g., a top major surface) of waveguide 680, and light buting elements 750 disposed on a major surface (e.g., a top major surface) of waveguide 690. In some other embodiments, the light distributing elements 730, 740, 750, may be disposed on a bottom major surface of associated waveguides 670, 680, 690, respectively. In some other ments, the light distributing ts 730, 740, 750, may be disposed on both top and bottom major surface of associated waveguides 670, 680, 690, respectively; or the light buting elements 730, 740, 750, may be disposed on different ones of the top and bottom major surfaces in different associated ides 670, 680, 690, respectively.

The waveguides 670, 680, 690 may be spaced apart and separated by, e.g., gas, liquid, and/or solid layers of material. For example, as illustrated, layer 760a may Knobbe, Martens te waveguides 670 and 680; and layer 760b may separate ides 680 and 690. In some embodiments, the layers 760a and 760b are formed of low refractive index materials (that is, materials having a lower refractive index than the al forming the immediately nt one of waveguides 670, 680, 690). Preferably, the refractive index of the material g the layers 760a, 760b is 0.05 or more, or 0.10 or less than the refractive index of the material forming the waveguides 670, 680, 690. Advantageously, the lower refractive index layers 760a, 760b may function as cladding layers that facilitate TIR of light through the waveguides 670, 680, 690 (e.g., TIR between the top and bottom major surfaces of each waveguide). In some embodiments, the layers 760a, 760b are formed of air. While not illustrated, it will be appreciated that the top and bottom of the illustrated set 660 of waveguides may include immediately neighboring cladding layers.

Preferably, for ease of manufacturing and other considerations, the material forming the waveguides 670, 680, 690 are similar or the same, and the material forming the layers 760a, 760b are similar or the same. In some embodiments, the material forming the waveguides 670, 680, 690 may be different between one or more ides, and/or the material g the layers 760a, 760b may be different, while still holding to the various refractive index relationships noted above.

With continued nce to , light rays 770, 780, 790 are incident on the set 660 of waveguides. It will be appreciated that the light rays 770, 780, 790 may be injected into the waveguides 670, 680, 690 by one or more image injection devices 360, 370, 380, 390, 400 (.

In some embodiments, the light rays 770, 780, 790 have different properties, e.g., different wavelengths or different ranges of wavelengths, which may correspond to different colors. The in-coupling optical elements 700, 710, 720 each deflect the incident light such that the light propagates through a respective one of the waveguides 670, 680, 690 by TIR.

For example, in-coupling optical element 700 may be configured to deflect ray 770, which has a first wavelength or range of wavelengths. Similarly, the transmitted ray 780 es on and is deflected by the in-coupling optical t 710, which is configured to deflect light of a second wavelength or range of wavelengths.

, Martens Likewise, the ray 790 is deflected by the in-coupling optical element 720, which is configured to selectively deflect light of third wavelength or range of wavelengths.

With ued reference to , the deflected light rays 770, 780, 790 are deflected so that they propagate through a corresponding waveguide 670, 680, 690; that is, the in-coupling l elements 700, 710, 720 of each waveguide deflects light into that corresponding waveguide 670, 680, 690 to in-couple light into that corresponding waveguide. The light rays 770, 780, 790 are deflected at angles that cause the light to ate through the respective ide 670, 680, 690 by TIR. The light rays 770, 780, 790 propagate through the respective ide 670, 680, 690 by TIR until impinging on the waveguide’s corresponding light distributing elements 730, 740, 750.

With reference now to , a perspective view of an example of the plurality of stacked waveguides of is illustrated. As noted above, the in-coupled light rays 770, 780, 790, are deflected by the in-coupling optical ts 700, 710, 720, respectively, and then propagate by TIR within the waveguides 670, 680, 690, respectively.

The light rays 770, 780, 790 then impinge on the light distributing elements 730, 740, 750, respectively. The light distributing elements 730, 740, 750 deflect the light rays 770, 780, 790 so that they propagate towards the out-coupling optical elements 800, 810, 820, respectively.

In some embodiments, the light distributing ts 730, 740, 750 are orthogonal pupil expanders (OPE’s). In some embodiments, the OPE’s both deflect or distribute light to the out-coupling l elements 800, 810, 820 and also increase the beam or spot size of this light as it propagates to the out-coupling optical elements. In some embodiments, e.g., where the beam size is already of a d size, the light distributing elements 730, 740, 750 may be omitted and the in-coupling optical elements 700, 710, 720 may be configured to deflect light directly to the out-coupling optical ts 800, 810, 820. For example, with reference to , the light distributing ts 730, 740, 750 may be replaced with out-coupling optical elements 800, 810, 820, respectively. In some embodiments, the upling optical elements 800, 810, 820 are exit pupils (EP’s) or exit pupil expanders (EPE’s) that direct light in a viewer’s eye 210 (. It will be appreciated that the OPE’s may be configured to increase the dimensions of the eye box in at Knobbe, Martens least one axis and the EPE’s may be to increase the eye box in an axis crossing, e.g., orthogonal to, the axis of the OPEs.

Accordingly, with reference to FIGS. 9A and 9B, in some embodiments, the set 660 of waveguides includes waveguides 670, 680, 690; in-coupling optical elements 700, 710, 720; light buting elements (e.g., OPE’s) 730, 740, 750; and out-coupling optical elements (e.g., EP’s) 800, 810, 820 for each component color. The waveguides 670, 680, 690 may be stacked with an air gap/cladding layer n each one. The in-coupling optical elements 700, 710, 720 redirect or deflect incident light (with different pling optical elements receiving light of different wavelengths) into its ide. The light then propagates at an angle which will result in TIR within the respective waveguide 670, 680, 690. In the example shown, light ray 770 (e.g., blue light) is deflected by the first incoupling optical element 700, and then continues to bounce down the waveguide, interacting with the light distributing element (e.g., OPE’s) 730 and then the out-coupling optical element (e.g., EPs) 800, in a manner bed earlier. The light rays 780 and 790 (e.g., green and red light, respectively) will pass through the waveguide 670, with light ray 780 impinging on and being deflected by in-coupling optical element 710. The light ray 780 then bounces down the waveguide 680 via TIR, proceeding on to its light distributing element (e.g., OPEs) 740 and then the out-coupling optical element (e.g., EP’s) 810. Finally, light ray 790 (e.g., red light) passes through the waveguide 690 to e on the light in-coupling optical elements 720 of the waveguide 690. The light in-coupling l ts 720 deflect the light ray 790 such that the light ray propagates to light distributing element (e.g., OPEs) 750 by TIR, and then to the out-coupling optical element (e.g., EPs) 820 by TIR. The out-coupling optical element 820 then finally out-couples the light ray 790 to the viewer, who also receives the out-coupled light from the other waveguides 670, 680. illustrates a top-down plan view of an example of the plurality of stacked waveguides of FIGS. 9A and 9B. As rated, the waveguides 670, 680, 690, along with each waveguide’s associated light distributing t 730, 740, 750 and associated upling optical element 800, 810, 820, may be vertically aligned. However, as discussed , the in-coupling optical elements 700, 710, 720 are not vertically aligned; , the in-coupling optical elements are preferably non-overlapping (e.g., laterally spaced apart as seen in the top-down view). As discussed further herein, this nonoverlapping spatial Knobbe, Martens arrangement facilitates the injection of light from different resources into different waveguides on a one-to-one basis, thereby allowing a specific light source to be uniquely coupled to a ic waveguide. In some embodiments, arrangements including nonoverlapping spatially-separated in-coupling optical elements may be referred to as a shifted pupil system, and the in-coupling optical elements within these arrangements may correspond to sub pupils.

LIQUID CRYSTAL GS Liquid crystals are partly ordered als whose les are often shaped like rods or plates that may be aligned along a certain direction. The direction and pattern along which the molecules of the liquid crystal are ed may be manipulated by the use of a template n that interacts with the molecules (e.g., through steric and/or anchoring energy interactions). In addition, the liquid crystal materials may comprise chiral dopants and/or reactive mesogens (RMs). The chiral dopants may cause rotation of the liquid crystal molecules over the thickness of the liquid l al and the ve mesogens may allow the orientations and positions of the liquid crystal molecules to be fixed through polymerization. The rotation may be by increments corresponding to a twist angle () such as shown in C.

As described herein, the in-coupling optical elements 700, 710, 720; light distributing elements (e.g., OPE’s) 730, 740, 750; and out-coupling optical elements (e.g., EP’s) 800, 810, 820 discussed above with reference to FIGS. 9A and 9B can include liquid crystal grating structures for steering light into and/or out of the waveguides 670, 680, 690.

The liquid crystal grating structures can preferably diffract or redirect light at large angles relative to a normal to the grating to, e.g., facilitate the in-coupling of light into a waveguide such that the light ates through the waveguide by TIR. Additionally, it may be preferable if the liquid crystal grating structures have high diffraction efficiencies for a wide range of incident angles. Some types of liquid crystal gs, i.e., polarization gratings, can exhibit high diffraction efficiencies over a wide range of incident angles at large diffraction angles, which can guide light into a waveguide by TIR. Conventional alignment methods, however, including photo-alignment and micro-rubbing techniques have challenges for scaling for volume manufacturing and fundamental limits in l ns of LC materials.

Knobbe, Martens LC alignment with imprint templates having velength features (e.g., nano-scale patterns) can allow for volume manufacturing and/or provide flexibility to create arbitrary spatial patterns.

Various embodiments of conventional diffraction gratings may achieve high diffraction encies for only a small range of wavelengths. Thus, they may not be capable of broadband operation. It has been found that metasurfaces comprising subwavelength features are capable of g the optical wavefront by altering phase, amplitude and/or polarization of an incoming light. LC material in which the LC molecules are aligned using an imprint template having nano-scale features that form a rface may be used to obtain a liquid crystal metasurface which may have optical properties that are ent from the optical properties of a liquid l bulk material. For example, a liquid crystal metasurface be broadband and have the ability to diffract incoming light in a wide range of wavelength incident in a wide range of incident angles with high efficiency. For example, a LC metasurface may be e of diffracting red, green and blue wavelengths of incoming light along a desired direction with approximately same diffraction efficiency. es of LC metasurface can include liquid crystal metamaterials and/or liquid crystal based Pancharatnam-Berry phase optical elements (PBPE).

Alignment of liquid crystal molecules using nano-imprint technology as discussed herein can be used to fabricate liquid crystal material with a plurality of distinct alignment ns with progressive transition (e.g., continuous transition) of the liquid crystal molecule director between neighboring alignment patterns. In various embodiments, grating period can refer to the distance between s of two utive liquid crystal les of a grating structure having longitudinal axes oriented along the same direction.

In some embodiments of liquid crystal als having a ity of neighboring alignment patterns, grating period can refer to the distance between centers of consecutive liquid crystal molecules of each alignment pattern.

Advantageously, various liquid crystal grating structures discussed herein are preferably configured to e high diffraction efficiency for a wide range of incident angles (e.g., between at least about grees about the surface normal, between at least about ±30-degrees about the surface normal, between at least about ±45-degrees about the surface normal, etc.). For example, the liquid crystal g structures can be configured to Knobbe, Martens provide a diffraction efficiency of at least about 10% (e.g., at least 20%, 30%, 40%, 50%, 60% or 75%) for light incident at an angle between about ±50 degrees with respect to a surface normal for wavelengths between about 400 nm and about 700 nm. Accordingly, the liquid crystal grating structures described herein may advantageously have low sensitivity to the angle of nce of light. In some embodiments, the liquid crystal grating structures discussed herein are configured to be narrowband. For example, the liquid crystal grating structures discussed herein can be configured to ct wavelengths in the visible al range between about 400 nm and about 450 nm; between about 450 nm and about 500 nm; between about 500 nm and about 550 nm; between about 550 nm and about 600 nm; between about 600 nm and about 650 nm; between about 650 nm and about 700 nm. In some other embodiments, the liquid crystal grating structures sed herein are configured to be broadband. For example, the liquid l grating structures sed herein can be configured to diffract wavelengths in the visible spectral range between about 400 nm and about 700 nm. As r example, the liquid crystal grating structures discussed herein can be configured to diffract wavelengths in the ultraviolet spectral range between about 250 nm – 400 nm. As yet another example, the liquid l grating structures discussed herein can be configured to diffract wavelengths in the infrared spectral range, such as, for example, between about 700 nm – 1 , between about 1 micron – 3 micron, n about 1.5 micron – 5 micron, between about 3 micron – 10 micron or any combination of these ranges or any subrange within these ranges or combination of sub-ranges. As another example, the g structures can be configured to diffract incident light having a wavelength in a range between about 300 nm and about 10 m. Preferably, when liquid crystal grating structures as discussed herein are employed in display applications, the grating structure is ured to diffract e light (e.g., in red, green and/or blue spectral ranges). In various embodiments, the liquid crystal grating structures can diffract visible light (such as in red, green and/or blue al ranges) so that the light propagates away from the grating structure at wide diffraction angles, e.g., angles suitable for TIR within a waveguide on which the grating structure may be formed. The liquid crystal grating structures discussed herein can have a grating period in the range between about 100 nm and about 100 m depending on the wavelength range that the grating structure is ured to operate on. For example, the periodicity of the grating structure may be between about 10 nm and about 50 nm; between Knobbe, Martens about 20 nm and about 60 nm; between about 30 nm and about 70 nm; between about 40 nm and about 80 nm; between about 50 nm and about 90 nm; n about 60 nm and about 100 nm; between about 100 nm and about 200 nm; between about 200 nm and about 350 nm; between about 330 nm and about 410 nm; between about 370 nm and about 480 nm; between about 450 nm and about 510 nm; between about 500 nm and about 570 nm; between about 550 nm and about 700 nm; between about 650 nm and about 1 m; between about 980 nm and about 3 m; between about 1.3 m and about 3.2 m; between about 2.3 m and about 5 m; between about 5 m and about 10 m; between about 5 m and about 20 m; between about 15 m and about 45 m; between about 25 m and about 60 m; between about 35 m and about 75 m; between about 45 m and about 100 m or any combination of these ranges or any subrange within these ranges or combination of sub-ranges.

The grating structures may be fabricated using a variety of methods including but not limited to aligning liquid crystal molecules in a layer of polymerizable liquid crystal material using a patterned alignment layer, which may underlie the liquid crystal material. The alignment layer may be ned using imprint technology or by using optical methods.

As discussed above, in some embodiments, the liquid crystal grating structures may form light redirecting elements for the various waveguides of the waveguide stacks 260 ( or 660 (FIGS. 9A-9C). For example, such liquid crystal grating structures may advantageously be applied to form the in-coupling optical elements 3012, 3014, 3016, and/or 3018 (-8E) and/or the in-coupling optical elements 700, 710, 720; the light distributing elements 730, 740, 750; and/or the out-coupling optical elements 800, 810, 820 (FIGS. . In addition to AR display systems, the liquid l g structures may be applied in other applications in which diffractive optical elements are utilized. For example, the liquid crystal grating structures may be utilized to steer light in other optical systems, including VR display systems, flat panel computer rs or televisions, nated signs, imaging systems, etc.

A illustrates a top-down perspective view of an example of a liquid crystal layer 1000 comprising a plurality of domains (e.g., s 1001a, 1001b, 1001c, 1001d, 1001e and 1001f) nt each other. The udinal axes of the liquid crystal molecules in each domain may be generally oriented along the same ion. The Knobbe, Martens longitudinal axes of the liquid crystal molecules in adjacent domains need not be oriented along the same direction. For example, the longitudinal axes of liquid crystal molecules in each domain 1001b and 1001d, which are adjacent to the domain 1001a, are oriented along a direction different from the direction along which the longitudinal axes of the liquid crystal les of domain 1001a are oriented. gh, in the ment illustrated in A only nine domains are illustrated, other embodiments may have fewer than or greater than nine domains. Furthermore, although only three different orientations of the longitudinal axes of the liquid crystal les are shown in A, other embodiments may comprise domains with more or less than three different orientations. Additionally, in various embodiments of liquid crystal , different domains can have different shapes and/or sizes. In various embodiments, the different domains can have different shapes (e.g., square, rectangular, hexagon, octagon, oval, , etc.). In various embodiments, different domains can have irregular shapes.

B illustrates a magnified top view of the liquid crystal layer 1000 illustrated in A. This top view of B shows the liquid crystal molecules on the top of the liquid crystal layer 1000 which may be referred to herein as the top-sublayer. The liquid crystal molecules beneath the top or uppermost liquid crystal molecules (e.g., beneath the top or uppermost sublayer) may have different ations as shown in C.

Figures10C-10F illustrate a cross-section view of the liquid along the axis X-X' of the liquid crystal layer 1000. The liquid crystal layer 1000 has two major surfaces 1002a and 1002b as seen in the cross-sectional view depicted in FIGS. 10C-10F. The two major surfaces 1002a and 1002b are intersected by a e normal 1003. The two major surfaces 1002a and 1002b extend in the x-y plane and the surface normal 1003 extends parallel to the z-axis. As noted from magnified top view ed in B, the longitudinal axes of uppermost liquid crystal molecules in the first domain 1001a are generally oriented parallel to the yaxis.

The longitudinal axes of liquid crystal molecules in the second domain 1001b are generally oriented at an angle (e.g., between about 30 degrees and 60 degrees) with respect to the y-axis. The longitudinal axes of liquid crystal molecules in the third domain 1001c are generally oriented dicular to the y- and z-axis.

The liquid crystal layer 1000 can be considered to have a plurality of sublayers , such as, for example, sub-layers 1010a, 1010b, 1010c, and 1010d. Each sublayer , Martens (e.g., 1010a, 1010b, 1010c, or 1010d) may be defined by a plurality of liquid crystal molecules arranged in a common plane and, as such, each sublayer may only be a single liquid l molecule thick. The sublayers form an ate layer of liquid crystal material having a thickness T, which may be equal to the total thickness of all sublayers.

While three/four sublayers are illustrated, it will be appreciated that the liquid crystal layer 1000 may include more or fewer sublayers.

In various embodiments the liquid crystal layer 1000 can comprise a chiral nematic liquid l material. For example, the plurality of sublayers of liquid crystal material may comprise a cholesteric liquid crystal material. In embodiments of liquid crystal layer 1000 comprising chiral materials, the liquid crystal molecules may have a twist angle  defined by the r rotation between the longitudinal axis of a liquid crystal molecule (e.g., 1005a) of a sub-layer (e.g., 1010a) of the liquid crystal layer 1000, and the longitudinal axis of an underlying liquid crystal molecule (e.g., 1005b) of an adjacent sub-layer (e.g., 1010b) as shown in C. The liquid crystal material may also be polymerizable. As discussed , the liquid crystal material may comprise a reactive n (RM), such as, for example, liquid crystalline di-acrylate. As also discussed herein, the liquid crystal layer 1000 can include chiral dopants. Examples of chiral dopants include cholesteryl benzoate, cholesteryl nonanoate, teryl chloride, and cholesteryl oleyl carbonate.

The liquid crystal r need not be chiral liquid crystal material. As shown in FIGS. 10D-10F, the longitudinal axes of the les of sub-layer 1010a are not twisted with respect to the molecules of the underlying sub-layers 1010b or 1010c. The longitudinal axes of the liquid crystal les can be aligned along any of the x, y or zaxis.

For example, as shown in D, the longitudinal axis of the liquid crystal molecules is d parallel to the y-axis. As another example, as shown in E, the longitudinal axis of the liquid l molecules is aligned parallel to the x-axis. As yet another example, as shown in F, the longitudinal axis of the liquid crystal les is aligned parallel to the z-axis. The side-views shown in FIGS. 10C-10F can correspond equally to FIGS. 10A or 10B.

With reference to FIGS. 10A and 10B, it may be desirable to introduce a small domain gap ʹdʹ between adjacent domains with different alignment patterns. The presence of the small gap between adjacent domains with different alignment patterns can Knobbe, Martens advantageously reduce occurrence of disclinations or other surface defects along the domain boundary during manufacture of the liquid crystal layer 1000. Reduced disclinations or other surface defects along the domain boundaries of the liquid crystal layer 1000 can reduce unwanted light scattering and other undesirable optical effects. The domain gap ʹdʹ can refer to the shortest ce between the nearest edges of an adjacent pair of domains. For example, in the illustrated embodiment, the domain gap between the domain 1001e and the domain 1001b is d1, the domain distance between the domain 1001e and the domain 1001d is d2, the domain distance between the domain 1001e and the domain 1001f is d3. The domain gap ʹdʹ between nt domains with different alignment patterns can be configured to achieve progressive transition of the longitudinal axes of the liquid crystal molecules between adjacent domains with different alignment patterns and have reduced occurrence of nations or other surface defects along the domain boundary. For example, the domain gap ʹdʹ between adjacent domains with different alignment patterns can be configured to achieve continuous transition of the longitudinal axes of the liquid crystal molecules between adjacent domains with different ent patterns. The domain gap between adjacent domains with different alignment patterns that is ured to achieve continuous transition of liquid l molecule can be less than 200 nm. For example, the domain gap between adjacent domains with different alignment ns can be between about 1 nm and about 20 nm, between about 5 nm and about 30 nm, between about 10 nm and about 50 nm, between about 25 nm and about 75 nm, between about 45 nm and about 100 nm, between about 60 nm and about 120 nm, between about 80 nm and about 150 nm, n 100 nm and about 200 nm or any combination of these ranges or any subrange within these ranges or combination of sub-ranges. As discussed above, the domain gaps are configured such that while the longitudinal axes of the liquid crystal les in each domain are aligned in accordance with the alignment pattern in each pattern, the udinal axes of the liquid l molecules in the gaps between adjacent domains are oriented to provide a gradient or graded transition such as generally smooth or continuous transition of the longitudinal axis of the liquid l les between adjacent domains.

The liquid crystal layer 1000 can be manufactured using an alignment layer comprising surface relief features. The surface relief features of the alignment layer can induce ent of molecules of a liquid crystal al deposited on the alignment Knobbe, Martens layer. Under certain conditions, the ing energy (W) provided by surface relief 3 D2 structures of an alignment layer, is given by the equation W  2 K , where K is the deformation constant of the liquid crystal material, D is the depth of the surface relief features of the alignment layer and Λ is the width or pitch nce between two utive surface relief features) of the surface relief features. Without any loss of lity, the anchoring energy (W) sed above can provide a measure of the energy required to change the udinal axes of the LC molecule from an initial direction to the desired direction in the plane of the liquid crystal e. From the above equation, it is noted that as the width or pitch of surface relief structures () is reduced (assuming the same aspect  D  ratio of the pattern, i.e., depth/period   is a constant), a higher anchoring energy is    provided by the surface relief features.

Accordingly, an alignment layer comprising surface relief features can be used to manufacture liquid crystal devices in which the liquid crystal molecules are aligned to the pattern formed by the surface relief features. The surface relief es of the alignment layer can comprise a wide variety of groove geometries that can vary in width, pitch and/or direction along length scales of the order of a few nanometers, a few hundred nanometers and/or a few microns. Since, the anchoring energy discussed above is inversely proportional to the cube of the width or pitch of the surface relief features, large variations in ing energy can be ed across the surface of the liquid crystal by making small variations in the width or pitch of the surface relief features. For example, consider an embodiment of an alignment layer including a first domain including a first set of surface relief features arranged to form a first pattern spaced apart by a region not including surface relief features from a second domain including a second set of surface relief features arranged to form a first pattern. Such an ment of the alignment layer can be used to fabricate a liquid crystal device with a first domain in which longitudinal axes of the liquid crystal molecules are aligned along directions of the first set of surface relief features and a second domain in which longitudinal axes of the liquid crystal molecules are aligned along directions of the second set of e relief features. The longitudinal axes of the liquid crystal molecules in the region of the liquid crystal device between the first and the second Knobbe, Martens domains can progressively transition from the directions of the first set of surface relief features to the directions of the second set of surface relief features. The domain gap can be selected such that the transition between the orientation of the udinal axes of the liquid crystal molecules of the first domain and the longitudinal axes of the liquid crystal molecules of the second domain is not abrupt or discontinuous but generally smooth. For example, the domain gap corresponding to the region of the alignment layer not including surface relief features can be ed such that the transition between the orientation of the longitudinal axes of the liquid crystal molecules of the first domain and the longitudinal axes of the liquid crystal molecules of the second domain is continuous.

In an ment of a method of manufacturing a liquid crystal device in which the liquid crystal molecules are aligned to a wide variety of groove geometries that can vary in width or period and/or direction along length scales of the order of a few ters, a few hundred nanometers and/or a few microns, the alignment layer can comprise a polymerizable liquid crystal (PLC), also known as reactive mesogen (RM). The alignment layer can be ctured by contacting a layer of PLC material with an t template comprising a wide y of grooves that can vary in width or period and direction along length scales of the order of a few nanometers, a few hundred nanometers and/or a few microns. The longitudinal axes of the molecules of the PLC layer can be allowed to ign to the grooves of the imprint template. For example, the longitudinal axes of the les of the PLC layer can self-align to the s of the imprint template upon application of heat, upon irradiation with UV light and/or after sufficient passage of time.

Once the longitudinal axes of the les of the PLC layer are self-aligned to the grooves of the imprint template, the PLC layer is polymerized for example by heat and/or ation with UV illumination. Polymerization advantageously fixes the longitudinal axes of the molecules of the PLC layer such that the orientation of the molecules of the PLC layer is maintained even after the PLC layer is separated from the imprint template.

Using an imprint template to manufacture the alignment layer comprising surface relief es having dimensions (e.g., length, width and/or depth) of the order of a few nanometers, a few hundred nanometers and/or a few microns and/or surface relief features arranged to form complex geometric patterns in which the direction and/or the period between consecutive features changes along length scales of the order of a few Knobbe, Martens nanometers, a few hundred nanometers and/or a few microns can be advantageous over other liquid crystal manufacturing methods such as, for example, the rubbing method or the photoalignment method. For example, as discussed above, it may not be cal to produce surface relief features of the having dimensions (e.g., length, width and/or depth) of the order of a few nanometers, a few hundred nanometers using some micro-rubbing methods that are low resolution methods. Additionally, it may not be possible to manufacture the alignment layer with the throughput necessary to e volume manufacturing using some rubbing methods. While, a photo-alignment method can be used to manufacture ent layer with uniform and non-uniform alignment of liquid l molecules, in some instances it may not be practical to produce alignment layer with complex spatial ns using the photoalignment method. Similarly to rubbing methods, it is hard to achieve the throughput necessary to achieve volume manufacturing of complex l LC patterns using some photo-alignment methods.

A illustrates a plan view of an embodiment of an imprint te 1100 comprising a plurality of features that can be used to manufacture a liquid crystal layer 1000, such as, for example, the layer 1000 shown in A. B illustrates a crosssectional view of the imprint template 1100 along the axis B-Bʹ. The imprint template 1100 comprises a plurality of domains (e.g., 1101a, 1101b and 1101c). Each of the plurality of domains includes a plurality of surface relief es. The surface relief features can include linear or curvilinear te grooves and/or sions, prisms, arcs, raised bumps or depressions. The surface relief features in each of the plurality of domains can be arranged to form a simple or x geometric pattern. The arrangement of the surface relief features can be configured to manipulate amplitude, phase and/or polarization of incident light to achieve a desired optical effect.

In various embodiments, each of the s can include sub-wavelength features. In such embodiments, a size of the surface relief features or a gap between adjacent surface relief features can have short length scales of the order of a few ters, a few hundred ters or a few microns. For example, a width ʹʹ of each surface relief feature in each of the plurality of domains can be between about 20 nm and about 100 nm, between about 30 nm and about 90 nm, between about 40 nm and about 80 nm, between about 50 nm and about 75 nm, between about 60 nm and about 70 nm or any combination of these ranges Knobbe, Martens or any ge within these ranges or combination of sub-ranges. As another example, a gap ʹʹ between utive features in each of the plurality of domains can be between about 20 nm and about 100 nm, between about 30 nm and about 90 nm, n about 40 nm and about 80 nm, between about 50 nm and about 75 nm, between about 60 nm and about 70 nm or any combination of these ranges or any subrange within these ranges or combination of nges. Without any loss of generality, the gap ʹʹ between consecutive features may correspond to the pitch. As yet another example, a depth (or height) ʹDʹ of the features in each of the plurality of domains can be between about 10 nm and about 100 nm, between about 20 nm and about 90 nm, between about 30 nm and about 80 nm, between about 40 nm and about 75 nm, between about 50 nm and about 70 nm or any combination of these ranges or any subrange within these ranges or combination of sub-ranges.

In various embodiments, the domain gap ʹdʹ between adjacent domains can be between about 10 nm and about 100 nm, between about 20 nm and about 90 nm, between about 30 nm and about 80 nm, between about 40 nm and about 75 nm, between about 50 nm and about 70 nm or any ation of these ranges or any subrange within these ranges or combination of sub-ranges. In various embodiments, the plurality of domains comprising e relief features can be arranged as a square grid across the surface of the imprint template 1100 such that the domain gap ʹdʹ between each pair of nt domains is uniform. In other embodiments, the plurality of domains comprising surface relief features can be arranged larly across the surface of the imprint te 1100 such that the domain gap ʹdʹ between different pairs of adjacent s is not uniform. As discussed above, the domain gap introduced between adjacent domains can help in reducing disclination or other surface defects that may occur along the domain boundaries during manufacture of the liquid crystal.

EXAMPLE METHOD OF CTURING A LIQUID CRYSTAL DEVICE FIGS. 12A-12D rates an example of a method of manufacturing various liquid crystal devices described herein. Referring to A, a polymer liquid crystal (PLC) layer 1203 is disposed over a ate 1201. The substrate 1201 is preferably optically transmissive. Examples of suitable materials for the substrate 1201 include glass, quartz, sapphire, indium tin oxide (ITO), or polymeric materials, including polycarbonate, polyacetate, and acrylic. In some embodiments, the substrate 1201 can be transmissive to Knobbe, Martens light of at least one of visible wavelengths or infrared wavelengths. The substrate can include a pair of major surfaces and surrounding edges. The major surface may be the largest area surface of the substrate, or may be one of a pair of rly-sized opposing surfaces each having larger areas than other surfaces. The liquid crystal devices can be configured to reflect, refract, diffract or otherwise redirect light incident on or with respect to the major surfaces of the substrate.

In some embodiments, the PLC layer 1203 is configured as an alignment layer that causes the liquid crystal molecules to assume a particular orientation or pattern, for example, due to steric interactions with the liquid crystal molecules, and/or anchoring energy exerted on the subsequently deposited liquid crystal les by the alignment layer.

The PLC layer 1203 can include rizable liquid l materials (reactive mesogen).

In some embodiments, the PLC layer 1203 can include ntaining polymers. The PLC layer 1203 can be disposed on one of the major surfaces of the substrate, e.g., by a spincoating process or jet deposition. The PLC layer 1203 can have a ess between about nm and 10 micron.

The PLC layer 1203 is imprinted with a plurality of surface relief features by bringing an exposed surface of the PLC layer into contact with an imprint template 1205 as depicted in FIGS. 12A and 12B. The imprint template 1205 can include features that are e of the features imprinted on the exposed surface of the PLC layer. In various embodiments, the imprint template 1205 can include features sub-wavelength dimensions.

For e, the imprint template 1205 can include features having dimensions (e.g., length, width and/or depth) of the order of a few nanometers, a few hundred nanometers and/or a few microns. For example, the imprint template 1205 can include features having a length greater than or equal to about 20 nm and less than or equal to about 100 nm. As another example, the t template 1205 can include features having a width greater than or equal to about 20 nm and less than or equal to about 100 nm. As yet another example, the imprint template 1205 can include features having a depth greater than or equal to about 10 nm and less than or equal to about 100 nm. In s embodiments, the length and/or width of the features can be greater than the depth of the es. However, in some embodiments, the depth can be approximately equal to the length and/or width of the features. The features of each domain of the imprint template 1205 can be arranged to form complex geometric , Martens patterns within each domain in which the direction and/or the period n consecutive features changes along length scales of the order of a few nanometers, a few hundred nanometers and/or a few microns. In various embodiments, the t template 1205 can include a plurality of spaced-apart domains. Each domain can include a plurality of features having sub-wavelength dimensions. Each domain can be spaced-apart from a neighboring domain by a domain gap. The domain gap can have a value between about 10 nm and about 100 nm, between about 20 nm and about 90 nm, between about 30 nm and about 80 nm, between about 40 nm and about 75 nm, between about 50 nm and about 70 nm or any ation of these ranges or any subrange within these ranges or combination of ges.

In various implementations, the domain gap can be less than or equal to 10 nm and/or greater than or equal to 100 nm. For example, the domain gap can be less than or equal to 5 nm, less than or equal to 2 nm, less than or equal to 1 nm or a value greater than or equal to 0 nm and less than or equal to 10 nm. The imprint template 1205 can have characteristics similar to the imprint template 1100 discussed above with reference to FIGS. 11A and 11B. For example, the plurality of domains of the imprint template 1205 can be arranged as a square grid across the surface of the imprint template 1205 such that the domain gap between neighboring domains is uniform. As another example, the plurality of domains of the imprint template 1505 can be ed as concentric circular or elliptical regions. In other embodiments, the plurality of domains can be arranged irregularly across the surface of the imprint template 1205 such that the domain gap n neighboring domains is not uniform.

The imprint template 1205 with sub-wavelength features can be designed and fabricated using atterning techniques including optical lithography, nano-imprint, and ion- and electron-beam lithography. In various embodiments, the imprint te can comprise a semiconductor material such as silicon or a glass material.

When PLC layer 1203 is in direct contact with features of the imprint template 1205, the longitudinal axes of the liquid crystal molecules of the PLC layer 1203 are aligned to the features of the imprint template. In this , the exposed surface of the PLC layer is ted with the pattern that corresponds to or is mentary to the pattern of the imprint template. After the exposed surface of the PLC layer 1203 is ned by the imprint template 1205, the PLC layer 1203 is polymerized. Polymerization of the Knobbe, Martens PLC layer 1203 can be achieved by a variety of methods including but not limited to re to ultraviolet (UV) radiation as shown in B, application of heat, passage of time, etc. Polymerization of the PLC layer 1203 can advantageously fix the orientation of the longitudinal axes of the liquid crystal molecules of the PLC layer 1203 even after the PLC layer 1203 is separated from the imprint te as shown in C.

After polymerization of the patterned PLC layer 1203, a layer of liquid crystal material 1207 is ed over the polymerized patterned PLC layer 1203. The liquid crystal layer can be deposited over the PLC layer 1203 by spin-coating, slot-coating, barcoating or jet deposition. The layer of liquid crystal material 1207 can have a ess between about 10 nm and 10 micron. The layer of liquid l material 1207 can include a doped or an un-doped liquid crystal material. In various embodiments, the layer of liquid crystal material 1207 can be a rizable liquid crystal material, polymer-stabilized liquid crystal material or a non-polymerizable liquid l al.

The longitudinal axes of the molecules of the layer of liquid crystal material 1207 align themselves to the pattern imprinted on the PLC layer 1203. Accordingly, the PLC layer 1203 serves as an alignment layer for the layer of liquid crystal material 1207.

In some embodiments, the alignment of the longitudinal axes of the molecules of the layer of liquid crystal material 1207 can be facilitated by ation of heat and/or sufficient passage of time. Using the PLC layer 1203 as an alignment layer for the layer of liquid crystal material 1207 can have several advantages. A first advantage is that the PLC layer 1203 can provide stronger alignment ions for the layer of liquid l material 1207 as compared to alignment layers that do not comprise a polymerizable liquid crystal material. A second advantage is that a homogeneous interface can be achieved when the material of the PLC layer 1203 has similar optical properties as the material of the layer of liquid crystal material 1207. This can advantageously reduce refractions/diffractions from the boundary between the PLC layer 1203 and the layer of liquid crystal material 1207.

As shown in E, additional PLC layers 1209 and 1213 that serve as alignment layers for additional liquid crystal layers 1211 and 1215 may be successively deposited over the aligned layer of liquid crystal material 1207 by repeating the ses of FIGS. 12A-12D. For example, the second PLC layer 1209 is disposed over the layer of liquid crystal material 1207 and subsequently patterned with an imprint template and Knobbe, Martens polymerized. A second layer of liquid crystal material 1211 is disposed over the patterned and polymerized PLC layer 1209 and allowed to self-organize such that the molecules of the second layer of liquid l material 1211 are d to the pattern ted on the second PLC layer 1209. The second PLC layer 1213 is disposed over the layer of liquid crystal material 1209 and subsequently patterned with an imprint template and polymerized. A third layer of liquid l material 1215 is disposed over the patterned and polymerized PLC layer 1213 and allowed to self-organize such that the molecules of the third layer of liquid l material 1215 are aligned to the pattern imprinted on the third PLC layer 1213. This sequence may be repeated for further liquid crystal layers. Preferably, the additional PLC layers 1209 and 1213 can se polymerizable liquid crystal materials (reactive mesogens). Preferably the liquid crystal material 1207, 1211 and 1215 can se polymerizable liquid crystal materials (reactive ns). The pattern imprinted on the PLC layers 1209 and/or 1213 can be different from the pattern imprinted on the PLC layer 1203. However, in some embodiments, the pattern imprinted on the PLC layers 1209 and/or 1213 can be identical to the pattern ted on the PLC layer 1203. In various embodiments, an isolation layer such as thin oxide film (with a thickness ranging from a few nm to a few hundred nm) may be deposited over the layers of liquid l material (e.g., layer 1207 or layer 1211) before providing additional PLC layers to reduce the effect of the pattern on the liquid crystal layers (e.g., layer 1207 or layer 1211) underneath. In some embodiments, a planarization template can be used to planarize the exposed surface of the layers of liquid crystal material (e.g., layer 1207, layer 1211 or layer 1215) before providing additional PLC layers.

A illustrates a scanning electron microscope (SEM) image of an embodiment of an imprint template. The imprint template comprises three domains 1301, 1303 and 1305 spaced-apart from each other by a domain gap. The domain gap between the first domain 1301 and the second domain 1303 is d1 and the domain gap between the second domain 1302 and the third domain 1305 is d2. Each of the three domains 1301, 1303 and 1305 comprise a plurality of es. A dimension (e.g., length, width or depth) of each of the plurality of es is less than 100 nm. The domain gaps d1 and d2 are less than or equal to 100 nm. B is a SEM image of a patterned PLC layer manufactured using the imprint template of A and the method discussed above with reference to FIGS. 12A- Knobbe, Martens 12C. C is a polarizing microscope image of the patterned PLC layer shown in B. C, s a gray-scale pattern that indicates the relative LC orientations with respect to the polarizer/analyzer of a polarizing microscope. It is noted from C that the polarizing microscope image exhibits a uniform pattern which indicates LC alignment that is substantially free of alignment s (i.e., disclinations).

The methods described herein can be used to fabricate electricallycontrollable liquid crystal devices including a liquid crystal layer with sub-wavelength features. illustrates an embodiment of an electrically-controllable liquid crystal device in which a liquid crystal layer 1407 whose molecules are aligned to a patterned alignment layer 1403 is sandwiched between two electrode layers 1420 and 1425. In some embodiments, the alignment layer 1403 can comprise a patterned rizable liquid crystal layer. In some embodiments, the alignment layer 1403 can include a patterned polymer layer which directly aligns LC materials with nano-scale surface ures. The two electrode layers 1420 and 1425 can comprise a material (e.g., Indium Tin Oxide (ITO) that is transmissive to light in the e spectral range (e.g., between about 400 nm and about 700 nm). In various embodiments, the two electrode layers 1420 and 1425 can each comprise a substrate 1401a and 1401b coated with a layer of ITO 1404a and 1404b respectively. In various embodiments, the electrically-controllable liquid crystal device can be manufactured by constructing a liquid l cell structure comprising the two electrode layers and the patterned alignment layer 1403. Liquid crystal material that forms the layer 1407 can be injected in the cell ure to fabricate the ically-controllable liquid crystal device. The alignment layer 1403 can have a thickness between about 20 nm and about 10 micron. The liquid crystal layer 1407 can have a thickness between about 100 nm and 10 micron. The alignment layer 1403 can be patterned using an t template sing a plurality of sub-wavelength features similar to the te 1100 and/or the te 1205 discussed above. For example, the imprint template used to pattern the alignment layer 1403 can include a plurality of space-apart domains. Each domain can include a plurality of features having a dimension (e.g., length, width and/or depth) of the order of a few nanometers, a few hundred nanometers or a few microns. As sed above, the alignment layer 1403 can be polymerized after patterning to fix the longitudinal axes of the molecules of the alignment layer 1403. The les of the liquid crystal layer 1407 Knobbe, Martens can be allowed to self-organize to the pattern imprinted on the alignment layer 1403. After self-organizing the molecules of the liquid crystal layer 1407 form distinct domains ponding to the distinct domains of the imprint template and the longitudinal axes of the liquid crystal molecules in each domain are aligned along the directions of the individual features in the corresponding domain. The longitudinal axes of the liquid crystal molecules in the gaps between adjacent domains can progressively transition from the orientation of the longitudinal axes of the molecules in one domain to the orientation of the longitudinal axis of the adjacent domain without any abrupt discontinuities. For e, the longitudinal axes of the liquid crystal molecules in the gaps between adjacent domains can progressively transition from the orientation of the longitudinal axes of the molecules in one domain to the orientation of the longitudinal axis of the adjacent domain ntially uously. In various ments, the liquid crystal layer 1407 can comprise complex, variant nano-scale patterns.

The orientation of the udinal axes of the liquid l molecules in one or more domains can be varied by applying an electric voltage across the electrode layers 1420 and 1425. Under certain conditions, for example, the LC molecules are d along the direction of electric fields across the electrode layers 1420 and 1425. Accordingly, by applying an electric voltage across the electrode layers 1420 and 1425, the grating structure in the liquid crystal layer 1407 can be switched on or switched off.

FIGS. 15A-15C illustrate an example of a method of manufacturing various liquid crystal devices described . The method comprises providing an imprint layer 1505 over a ate 1501. Various physical and/or chemical teristics of the imprint layer 1505 and the substrate 1501 can be similar to the imprint template 1205 and the substrate 1201 respectively that are discussed above. For example, in many cases, the substrate 1501 is optically issive. Examples of suitable materials for the substrate 1501 include glass, quartz, sapphire, indium tin oxide (ITO), or polymeric materials, including polycarbonate, polyacetate, and acrylic. In some implementations, the substrate 1501 can be transmissive to light of at least one of visible wavelengths or infrared wavelengths. The substrate can include a pair of major surfaces and surrounding edges. The major surface may be the largest area surface of the substrate, or may be one of a pair of rly-sized opposing surfaces each having larger areas than other surfaces (e.g., edges).

Knobbe, Martens The liquid crystal devices can be configured to reflect, refract, diffract or otherwise redirect light incident on or with respect to the major surfaces of the substrate.

The imprint layer 1505 can be disposed over a major surface of the substrate 1501. As discussed above, the imprint layer 1505 can include features having subwavelength dimensions. For example, the imprint layer 1505 can include es having ions (e.g., length, width and/or depth) of the order of a few nanometers, a few hundred nanometers and/or a few microns. As another example, the imprint layer 1505 can include features having a length greater than or equal to about 20 nm and less than or equal to about 100 nm. As yet r example, the imprint layer 1505 can include features having a width greater than or equal to about 20 nm and less than or equal to about 100 nm. As yet another example, the imprint layer 1505 can include features having a depth greater than or equal to about 10 nm and less than or equal to about 100 nm. In s embodiments, the length and/or width of the es can be greater than the depth of the features. However, in some embodiments, the depth can be approximately equal to the length and/or width of the es. Features having dimensions outside these ranges are also possible though.

The features of each domain of the imprint layer 1505 can be arranged to form complex geometric patterns within each domain in which the direction and/or the period between consecutive es changes along length scales of the order of a few nanometers, a few hundred nanometers and/or a few microns. In various embodiments, the imprint layer 1505 can e a plurality of spaced-apart domains. Each domain can include a plurality of features having sub-wavelength dimensions. Each domain can be -apart from a neighboring domain by a domain gap. The domain gap can have a value between about 10 nm and about 100 nm, between about 20 nm and about 90 nm, between about 30 nm and about 80 nm, between about 40 nm and about 75 nm, between about 50 nm and about 70 nm or any combination of these ranges or any subrange within these ranges or combination of sub-ranges. In various entations, the domain gap can be less than or equal to 10 nm and/or greater than or equal to 100 nm. For example, the domain gap can be less than or equal to 5 nm, less than or equal to 2 nm, less than or equal to 1 nm or a value greater than or equal to 0 nm and less than or equal to 10 nm. In some implementations, the plurality of domains of the imprint template 1505 can be ed as a square grid across the surface of the imprint template 1505 such that the domain gap between neighboring domains Knobbe, Martens is uniform. In some implementations, the plurality of domains of the imprint template 1505 can be arranged as concentric circular or elliptical regions. The plurality of domains can be arranged irregularly across the surface of the imprint template 1505 such that the domain gap between neighboring domains is not m. The t layer 1505 can have characteristics similar to the imprint template 1100 and/or the imprint 1205 sed above.

The imprint layer 1505 with sub-wavelength features can be ed and fabricated using nano-patterning techniques including optical lithography, nano-imprint, and ion- and electron-beam lithography. In various embodiments, the t layer 1505 can comprise a semiconductor material such as photoresist, n or a glass material.

A polymerizable liquid l (PLC) layer 1503 is disposed over the imprint layer 1505. The PLC layer 1503 can be disposed over the imprint layer 1505, by a spin-coating process or jet tion. The PLC layer 1503 can have a thickness between about 10 nm and 10 micron. The PLC layer 1503 can include polymerizable liquid crystal materials (e.g., reactive mesogen) and/or Azo-containing rs. The t layer 1505 acts as an ent layer that causes the liquid crystal molecules of the PLC layer 1503 to align to the pattern of the imprint layer 1505. When the PLC layer 1503 is in contact with features of the imprint layer 1505, the longitudinal axes of the liquid crystal molecules of the PLC layer 1503 may be aligned to the features of the imprint layer 1505. In this manner, the surface of the PLC layer 1503 is imprinted with the pattern that corresponds to the n of the imprint layer 1503. The alignment of the liquid l molecules of the PLC layer 1503 to the pattern of the imprint layer 1505 can be attributed to steric interactions with the liquid crystal molecules, and/or anchoring energy exerted on deposited liquid crystal molecules by the imprint layer 1505. The PLC layer 1503 can be polymerized after deposition on the imprint layer 1505. rization of the PLC layer 1503 can be achieved by a variety of methods including but not limited to exposure to ultraviolet (UV) radiation, application of heat, passage of time, or combinations thereof. Polymerization of the PLC layer 1503 can advantageously fix the orientation of the longitudinal axes of the liquid crystal molecules of the PLC layer 1503.

After polymerization of the patterned PLC layer 1503, another layer of liquid crystal material 1520 is disposed over the polymerized patterned PLC layer 1503. The layer 1520 of the liquid crystal material can be deposited over the PLC layer 1503 by spin- Knobbe, Martens coating, slot-coating, bar-coating, blade-coating, jet deposition, or possibly other methods.

The layer of liquid crystal material 1520 can have a thickness between about 10 nm and 10 micron. The layer of liquid l material 1520 can include a doped or an un-doped liquid crystal material. In various embodiments, the layer of liquid crystal material 1520 can be a polymerizable liquid crystal material, polymer-stabilized liquid crystal material or a nonpolymerizable liquid crystal material.

The longitudinal axes of the molecules of the layer of liquid crystal material 1520 align lves to the pattern imprinted on the PLC layer 1503. In various implementations, only the molecules of the sub-layer of the layer of liquid crystal material 1520 that is in contact with the imprint layer 1505 may their longitudinal axes aligned to the pattern of the imprint layer 1505. Other sub-layers of the layer of liquid crystal material 1520 may have different orientations as sed above with nce to C.

Accordingly, the PLC layer 1503 serves as an alignment layer for the layer of liquid crystal material 1520. In some ments, the alignment of the longitudinal axes of the molecules of the layer of liquid crystal material 1520 can be facilitated by application of heat and/or ient passage of time.

As discussed above, using the PLC layer 1503 as an alignment layer for the layer of liquid crystal material 1520 can have several advantages. A first advantage is that the PLC layer 1503 can provide stronger alignment conditions for the layer of liquid l material 1520 as compared to alignment layers that do not comprise a polymerizable liquid crystal material. A second advantage is that a homogeneous interface can be achieved when the material of the PLC layer 1503 has similar optical properties as the material of the layer of liquid l material 1520. This can advantageously reduce refractions/diffractions from the boundary between the PLC layer 1503 and the layer of liquid crystal material 1520.

The methods sed herein may be used to fabricate liquid crystal metamaterials or liquid crystal metasurfaces. Various ments of liquid crystal layers comprising different spaced apart domains, the domain including a plurality of subwavelength scale pattern, may be formed on a substrate, which may be adjacent a transmissive waveguide or the waveguide itself as a substrate. In such embodiments, the liquid l layers with velength scale pattern may be configured, for example, to diffract light nt at an angle between about ±30 degrees with t to a normal to the Knobbe, Martens waveguide such that the diffracted light can be coupled into a guided mode of a waveguide disposed adjacent to the liquid crystal layer. In some embodiments, the waveguide can be disposed directly adjacent the liquid crystal layer without any intervening layers. In some other embodiments, intervening layers can be disposed between the waveguide and the liquid l layer adjacent to the waveguide. In some such embodiments, the liquid crystal layers with velength scale pattern may also be configured to out-couple light propagating through the waveguide. The liquid crystal layers with sub-wavelength scale pattern may be configured to be narrowband such that they can be wavelength selective or broadband such that they can efficiently diffract light over a wide range of wavelengths (e.g., ngths in the red/green/blue spectral range of the visible spectrum). The methods discussed herein can be used to ate other liquid l devices. For example, the methods discussed herein can be used to fabricate implementations of diffractive liquid crystal lens as discussed below.

DIFFRACTIVE LIQUID CRYSTAL LENS A illustrates a top view of an implementation of a diffractive lens 1600 comprising a liquid crystal material. The lens 1600 comprises a plurality of zones, such as, for example, zones 1605 and 1610 in the x-y plane. The number of the plurality of zones can be between 2 and about 50. For example, the number of the plurality of zones can be greater than or equal to 3, r than or equal to 5, greater than or equal to 8, greater than or equal to 10, greater than or equal to 15, greater than or equal to 18, greater than or equal to 22, less than or equal to 50, less than or equal to 42, less than or equal to 30, less than or equal to 20, or any number in the ranges/sub-ranges defined by these . The molecules of the liquid crystal material in each of the plurality of zones of the lens 1600 are oriented along a particular orientation or range thereabout. The orientation of the molecules of the liquid crystal al in adjacent zones can be different. For example, in the lens 1600, the udinal axes of the liquid crystal molecules in the zone 1605 can be aligned parallel to the y-axis while the longitudinal axes of the liquid crystal molecules in the zone 1610 can be rotated in a wise direction by an angle of about 18 degrees with respect to the y-axis.

In the lens 1600 depicted in A, the longitudinal axes of the molecules in each of the successive zones can be rotated in a clock-wise direction by an angle of about 18 degrees with respect to the longitudinal axes of the liquid l molecules of the preceding zone. In other lens entations, the angle between the longitudinal axes of the liquid crystal Knobbe, Martens molecules in a zone and the longitudinal axes of the liquid crystal molecules in a preceding zone can be other than 18 degrees. For example, angle between the longitudinal axes of the liquid crystal molecules in a zone and the longitudinal axes of the liquid crystal molecules in a preceding zone can be less than or equal to about 45 degrees. For example, angle between the udinal axes of the liquid crystal molecules in a zone and the longitudinal axes of the liquid crystal molecules in a preceding zone can be greater than or equal to about 1 degree, greater than or equal to about 2 degrees, greater than or equal to about 5 degrees, less than or equal to about 10 degrees, less than or equal to about 17 degrees, less than or equal to about degrees, less than or equal to about 25 s, less than or equal to about 30 degrees, less than or equal to about 35 s, less than or equal to about 40 degrees and/or less than or equal to about 45 degrees or any angle in any range defined by any of these values.

In the implementation of the lens 1600 depicted in A, the angle between the direction of the longitudinal axes of the liquid l molecules and the y-axis progressively increases by a fixed amount (e.g., 18 degrees) such that the liquid crystal les in the tenth zone 1655 have the same orientation as the liquid crystal molecules in the first zone 1605. However, the angular difference in the orientation of the longitudinal axes of the liquid crystal molecules in neighboring zones need not be fixed or constant.

Instead, the difference in the orientation angle of the longitudinal axes of the liquid crystal molecules n neighboring zones can vary across the lens. For example, the angular difference in the orientation of the longitudinal axes of the liquid crystal molecules between two neighboring zones can be 35 degrees, while the angular difference in the orientation of the longitudinal axes of the liquid crystal molecules between two other neighboring zones can be 10 degrees. Accordingly, in various implementations of the liquid crystal lens, the angular difference in the orientation of the longitudinal axes of the liquid crystal molecules between sive zones can be variable, non-constant, and/or random.

The ity of zones can be ring shaped or annular. The plurality of zones can be concentric. For example, in A, the first zone 1605 is configured as a central zone that is surrounded by the other ity of zones. The ity of zones can be concentric rings or annuluses as depicted in A. However, in other implementations, the plurality of zones can be elliptical or possibly have other shapes. The plurality of zones need not be closed curves. Instead, some of the ity of zones can be open curves (e.g., Knobbe, Martens arcs). In various implementations, the width of the plurality of zones can reduce as the distance from the first (or central) zone increases. Accordingly, the width of the first (or central) zone can be the largest and the width of each consecutive zone can successively reduce. The width of the ity of zones can reduce linearly or non-linearly as the distance from the central zone increases and/or center of the lens. The width of the plurality of zones can be governed by a mathematical equation in some cases.

In various implementations, the regions and the features contained therein are configured, e.g., have a shape, size, orientation, etc., such that the plurality of zones form an optical element such as a lens having optical power. This power may be positive or negative. The optical power may be ve or negative also depending on the polarization of incident light. For example, the optical power is positive for right-handed circular polarized light while negative for left-handed circular polarized light, and vice versa. This optical element, e.g., lens, may be a diffractive optical element such as a ctive lens.

Each of the plurality of zones can be considered as a domain as discussed above. The plurality of the zones can be spaced apart from each other with a gap (corresponding to the domain gap) between about 1 nm and about 200 nm. However, in various implementations, the plurality of zones can be arranged such that they are spaced apart by a gap less than 5.0 nm or less than 1.0 nm. For example, in some implementations, there is no gap between the plurality of zones. In other words, the gap between adjacent zones can be 0. The domain gap may vary ing on the angular difference in the orientation of the longitudinal axes of the liquid crystal molecules in neighboring zones.

Accordingly, ing on the difference in the orientation of the longitudinal axes of the liquid l molecules between neighboring zones, the gap can be between 0 and about 200 B illustrates a copic image of the lens 1600 between crossed zers ed on either side of the lens 1600. The crossed polarizers can be linear zers whose polarization axes are disposed orthogonal to each other. The crossed polarizer will show the different regions, which rotate polarization by different s, as having different intensities depending on how much the polarization of light matches the polarizer orientation. The more the polarization of light matches the polarizer, the er the light and vice versa. To obtain the microscopic image of the lens 1600 circularly Knobbe, Martens polarized light itted through one of the two crossed polarizers is incident on lens 1600.

The output of the lens 1600 is transmitted h the other of the two crossed zers and observed through a microscope. The orientation of the udinal axes of the liquid crystal molecules in dark regions of the image ed (e.g., region 1660) in B are parallel or perpendicular to the optic axes of the polarizers. The orientation of the longitudinal axes of the liquid crystal molecules in bright regions of the image depicted in B (e.g., region 1662) are approximately ±45 degrees with respect to the optic axes of the polarizers.

Variation n the brighter and darker regions is ated with variation in the polarization orientation which is caused by the different ations of the liquid crystal molecules and the optic axis of the birefringence in the particular region.

The alignment of the longitudinal axes of the plurality of the liquid crystals in the plurality of zones can be achieved by using an imprint layer as discussed above. B-1 depicts a scanning electron microscope (SEM) image showing the pattern of the imprint layer 1670 that achieves the desired alignment of the longitudinal axes of the plurality of the liquid crystals in the region 1664 comprising the zones 1605 and 1610. The SEM image in B-2 shows the pattern of the imprint layer 1670 that achieves the desired alignment of the longitudinal axes of the plurality of the liquid crystals in the region 1666. The region 1672 of the imprint layer 1670 comprises features (e.g., s) that are parallel to the y-axis. As a result, the longitudinal axes of the liquid crystal molecules that overlap with the region 1672 of the imprint layer 1670 are d parallel to the y-axis to form the zone 1605. The region 1674 of the imprint layer 1670 comprises features (e.g., grooves) that are rotated clock-wise by an angle (e.g., about 18 degrees) with respect to the . Accordingly, the longitudinal axes of the liquid crystal molecules that overlap with the region 1674 of the imprint layer 1670 are rotated wise by an angle (e.g., about 18 degrees) with respect to the y-axis to form the zone 1610. The regions 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 show different arrangements of features (e.g., grooves). The longitudinal axes of the liquid crystal molecules that overlap with the regions 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 would be aligned parallel to the grooves in the tive regions 1680, 1682, 1684, 1686, and 1688.

The features in the various regions 1672, 1674, 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 can be sub-wavelength size. For example, a length, a Knobbe, Martens height, a width and/or a depth of the features in the various regions 1672, 1674, 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 can be of the order of a few nanometers, a few hundred nanometers or a few microns. As another example, a length, a height, a width and/or a depth of the features in the various regions 1672, 1674, 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 can be between about 20 nm and about 100 nm, between about 30 nm and about 90 nm, between about 40 nm and about 80 nm, between about 50 nm and about 75 nm, between about 60 nm and about 70 nm or any combination of these ranges or any subrange within these ranges or combination of sub-ranges. In various implementations, a length, a , a width and/or a depth of the features in the s regions 1672, 1674, 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 can be less than or equal to about 20 nm or greater than or equal to about 100 nm. For example, the length, a height, a width and/or a depth of the features in the various regions 1672, 1674, 1680, 1682, 1684, 1686, and 1688 of the imprint layer 1670 can be r than or equal to 1 nm, greater than or equal to 5 nm, greater than or equal to 10 nm, greater than or equal to 15 nm, less than or equal to 100 nm, less than or equal to 125 nm, less than or equal to 150 nm, less than or equal to 200 nm, less than or equal to 250 nm, less than or equal to 1 , or a value in any range/sub-range defined by these .

FIGS. 17A-17C illustrate an example of a method of manufacturing the lens 1600. The method comprises providing an imprint layer 1670 over a substrate 1701.

Various al and/or chemical teristics of the imprint layer 1670 and the substrate 1701 can be r to the liquid crystal layer 1203 and the substrate 1201 respectively that are discussed above. For example, in various cases the substrate 1701 is optically transmissive and/or transparent. Examples of suitable materials for the substrate 1701 include glass, quartz, sapphire, indium tin oxide (ITO), or polymeric materials, including polycarbonate, polyacetate, and acrylic. In some embodiments, the substrate 1701 can be transmissive to light of at least one of visible wavelengths or infrared wavelengths. The substrate can include a pair of major surfaces and surrounding edges. The major surface may be the t area surface of the substrate, or may be one of a pair of rly-sized opposing surfaces each having larger areas than other surfaces (e.g., edges). The liquid crystal devices can be configured to reflect, refract, diffract or otherwise redirect light incident on or with respect to the major surfaces of the ate.

Knobbe, Martens The imprint layer 1670 can be disposed over a major surface of the substrate 1701. As discussed above, the imprint layer 1670 comprises a plurality of zones comprising features (e.g., grooves). The features can have sub-wavelength dimensions. For example, the imprint layer 1670 can include features having ions (e.g., length, width and/or depth) of the order of a few ters, a few hundred nanometers and/or a few microns. As another example, the imprint layer 1670 can include features having a length greater than or equal to about 20 nm and less than or equal to about 100 nm. As yet another example, the imprint layer 1670 can include features having a width greater than or equal to about 20 nm and less than or equal to about 100 nm. As yet another example, the imprint layer 1670 can include features having a depth greater than or equal to about 10 nm and less than or equal to about 100 nm. In various embodiments, the length and/or width of the features can be greater than the depth of the features. However, in some ments, the depth can be approximately equal to the length and/or width of the features. Other dimensions outside these ranges are also possible.

In various implementations, the features in each of the plurality of zones are ed along the same direction. The ion along which the features in one of the plurality of zones are oriented may be rotated by an angle with t to the direction along which the features in a zone adjacent to one of the ity of zones is ed. The plurality of zones domain can be spaced-apart from each other by a gap having a value between about 1 nm and about 100 nm, between about 20 nm and about 90 nm, between about 30 nm and about 80 nm, between about 40 nm and about 75 nm, between about 50 nm and about 70 nm or any combination of these ranges or any subrange within these ranges or combination of sub-ranges. In some implementations, the plurality of zones can be spacedapart by a gap less than about 5 nm or 1 nm. In some entations, the plurality of zones can be spaced-apart by no gap (or a gap of 0 nm). The plurality of zones can ring shaped and can be arranged concentrically. The width of plurality of zones can decrease as the distance from the center of the imprint layer 1705 increases.

The imprint layer 1705 with velength features can be fabricated using nano-patterning techniques including optical lithography, nano-imprint, and ion- and electron-beam lithography. In various embodiments, the imprint layer 17505 can comprise a semiconductor material such as photoresist, silicon or a glass material.

Knobbe, Martens A liquid crystal (LC) layer 1703 is ed over the imprint layer 1705.

The liquid crystal layer 1703 can be a polymerizable liquid crystal layer. The LC layer 1703 can be disposed over the imprint layer 1705, by a spin-coating process, slot-die coating s, bar-coating process, die coating process or jet deposition. The LC layer 1703 can have a thickness between about 10 nm and 10 micron. The LC layer 1503 can include polymerizable liquid crystal materials (e.g., reactive mesogen) and/or Azo-containing polymers. The imprint layer 1705 acts as an alignment layer that causes the liquid crystal molecules of the LC layer 1703 to align to the pattern of the imprint layer 1705. When the LC layer 1703 is in contact with features of the imprint layer 1705, the longitudinal axes of the liquid crystal molecules of the LC layer 1703 can align with the features of the imprint layer 1705. In this manner, the e of the LC layer 1703 is imprinted with the pattern that corresponds to the pattern of the imprint layer 1705. The LC layer 1703 can be polymerized after deposition on the imprint layer 1505. Polymerization of the LC layer 1703 can be achieved by a variety of methods including but not limited to exposure to ultraviolet (UV) radiation 1710 such as schematically illustrated in C, application of heat, passage of time, or combinations thereof. Polymerization of the LC layer 1703 can advantageously fix the orientation of the longitudinal axes of the liquid crystal les of the PLC layer 1703.

A illustrates a ng on microscope (SEM) image of an imprint layer 1670 provided on a substrate comprising n (Si). As depicted in A, the imprint layer 1670 comprises a first zone having a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction ent from the first direction. The first and the second zones are spaced by a gap less than 1 nm (e.g., no gap).

B illustrates a scanning electron microscope (SEM) image of a liquid crystal layer 1703 ed over the t layer 1670. The longitudinal axes of the liquid crystal les in the portion of the liquid crystal layer 1703 that overlaps with the first zone are aligned along the first direction and the longitudinal axes of the liquid crystal molecules in the portion of the liquid crystal layer 1703 that overlaps with the second zone are aligned along the second direction.

Knobbe, Martens It is contemplated that various embodiments may be implemented in or ated with a variety of ations such as imaging systems and devices, display systems and devices, spatial light modulators, liquid crystal based s, polarizers, wave guide plates, etc. The structures, devices and methods bed herein may particularly find use in displays such as wearable displays (e.g., head d displays) that can be used for augmented and/or virtually reality. More generally, the described embodiments may be implemented in any device, apparatus, or system that can be configured to y an image, whether in motion (such as video) or stationary (such as still images), and whether textual, graphical or pictorial. It is contemplated, however, that the described embodiments may be included in or ated with a y of electronic devices such as, but not limited to: mobile telephones, multimedia Internet enabled cellular telephones, mobile television receivers, wireless devices, smartphones, Bluetooth® devices, personal data assistants , wireless electronic mail ers, hand-held or portable computers, netbooks, oks, smartbooks, tablets, printers, copiers, scanners, facsimile s, global positioning system (GPS) receivers/navigators, cameras, digital media players (such as MP3 players), camcorders, game consoles, wrist s, clocks, ators, television monitors, flat panel displays, electronic reading devices (e.g., e-readers), computer monitors, auto displays (including odometer and speedometer displays, etc.), cockpit controls and/or displays, camera view displays (such as the display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, microwaves, erators, stereo systems, cassette recorders or players, DVD players, CD players, VCRs, radios, le memory chips, washers, dryers, washer/dryers, parking meters, head mounted displays and a y of imaging systems. Thus, the teachings are not intended to be limited to the embodiments depicted solely in the figures, but instead have wide applicability as will be readily apparent to one having ry skill in the art.

Various modifications to the embodiments described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of this disclosure. Various changes may be made to the invention described and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular situation, material, composition of Knobbe, Martens matter, process, process act(s) or step(s) to the objective(s), spirit or scope of the present invention. All such modifications are intended to be within the scope of claims associated with this disclosure.

The word “exemplary” is used exclusively herein to mean “serving as an example, instance, or illustration.” Any embodiment bed herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

Additionally, a person having ry skill in the art will readily appreciate, the terms ” and “lower”, ” and “below”, etc., are sometimes used for ease of describing the figures, and te relative positions corresponding to the orientation of the figure on a properly oriented page, and may not reflect the orientation of the structures described herein, as those structures are implemented.

Certain features that are described in this specification in the context of separate embodiments also can be implemented in combination in a single embodiment.

Conversely, various features that are described in the context of a single embodiment also can be implemented in le embodiments separately or in any suitable subcombination.

Moreover, although features may be bed above as acting in certain combinations and even initially claimed as such, one or more features from a d combination can in some cases be d from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may tically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel sing may be advantageous. er, the separation of various system components in the embodiments described above should not be tood as requiring such separation in all embodiments, and it should be understood that the bed program ents and systems can generally be integrated together in a single software product or Knobbe, Martens packaged into multiple software products. Additionally, other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.

The invention includes s that may be performed using the subject devices. The methods may comprise the act of providing such a le device. Such provision may be performed by the end user. In other words, the ding” act merely requires the end user obtain, access, approach, position, set-up, activate, power-up or otherwise act to provide the ite device in the subject . Methods recited herein may be carried out in any order of the recited events which is logically possible, as well as in the recited order of events.

Example aspects of the invention, er with details regarding material selection and manufacture have been set forth above. As for other details of the present invention, these may be appreciated in connection with the above-referenced patents and publications as well as generally known or appreciated by those with skill in the art. The same may hold true with t to method-based aspects of the invention in terms of additional acts as commonly or logically employed.

In addition, though the invention has been described in reference to several examples optionally incorporating s features, the invention is not to be limited to that which is described or indicated as contemplated with respect to each variation of the invention. Various s may be made to the invention described and equivalents (whether recited herein or not included for the sake of some brevity) may be tuted without departing from the true spirit and scope of the invention. In on, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the invention.

Also, it is contemplated that any optional feature of the inventive variations bed may be set forth and claimed independently, or in combination with any one or more of the features described herein. Reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in claims associated hereto, the singular forms “a,” “an,” “said,” and “the” include plural referents unless the specifically stated otherwise. In other words, use of the articles allow for Knobbe, Martens “at least one” of the subject item in the description above as well as claims associated with this disclosure. It is further noted that such claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such ive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

Without the use of such exclusive terminology, the term “comprising” in claims associated with this disclosure shall allow for the inclusion of any additional element - irrespective of whether a given number of elements are enumerated in such claims, or the addition of a feature could be regarded as transforming the nature of an element set forth in such claims. Except as specifically defined herein, all technical and scientific terms used herein are to be given as broad a commonly understood g as possible while maintaining claim validity.

The h of the present invention is not to be limited to the examples provided and/or the subject specification, but rather only by the scope of claim language associated with this disclosure.

The reference in this ication to any prior publication (or ation derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that the prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this ication relates.

, Martens

Claims (28)

WHAT IS CLAIMED IS

1. An optical device, comprising: a patterned substrate comprising at least a first zone sing a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction, wherein the first plurality of features and the second ity of features have a dimension less than or equal to about 100 nm; and a liquid crystal layer over the patterned substrate; wherein les of the liquid crystal layer are self-aligned to the first and the second plurality of features.

2. The optical device of Claim 1, wherein the patterned substrate comprises a substrate having a layer ed n that is patterned.

3. The optical device of Claim 1 or Claim 2, n the at least first and second zones comprise concentric ring-shaped zones.

4. The optical device of any one of the Claims 1 to 3, comprising at least five zones.

5. The optical device of any one of the Claims 1 to 4, wherein a width of the zones progressively decrease with distance from a center of the patterned substrate.

6. The optical device of any one of the Claims 1 to 5, wherein the zones have no gap therebetween.

7. The l device of any one of the Claims 1 to 6, wherein a gap between the zones is less than or equal to 1 nm.

8. The optical device of any one of the Claims 1 to 7, n a gap between the zones is less than or equal to 5 nm.

9. The optical device of any one of the Claims 1 to 8, wherein the dimension comprise a length or width of the feature.

10. . The optical device of any one of the Claims 1 to 9, wherein the liquid crystal comprises polymerized liquid crystal.

11. The optical device of any one of the Claims 1 to 10, wherein the optical device comprises a diffractive lens.

12. The optical device of any one of the Claims 1 to 11, configured to provide optical power. Knobbe, Martens

13. The optical device of any one of the Claims 1 to 12, n: the patterned substrate comprises a substrate upon which a material is disposed, the material has a first surface adjacent the substrate and a second surface opposite the first surface, the material comprises: the first zone arranged to form a first pattern on the second surface, and the second zone arranged to form a second pattern on the second surface, the first pattern is spaced apart from the second pattern by a gap having a distance n about 20 nm and about 100 nm, and the liquid crystal layer is on the second surface of the material.

14. The optical device of Claim 13, wherein the material comprises a polymerizable liquid crystal material.

15. The optical device of Claim 13 or Claim 14, included with an eyepiece of a head mounted display.

16. The optical device of Claim 15, ured to selectively in-couple at least one light stream from a multiplexed light stream into a waveguide of the eyepiece and transmit one or more other light streams from the multiplexed light .

17. A method for fabricating an optical , the method comprising: providing an imprint layer over a substrate, the imprint layer comprising at least a first zone comprising a first plurality of features oriented along a first direction and a second zone comprising a second plurality of features oriented along a second direction; and depositing a liquid crystal layer on the imprint layer; n molecules of the deposited liquid crystal layer are self-aligned to the first and the second plurality of features.

18. The method of Claim 17, wherein the first and the second zones are spaced apart by a gap less than or equal to about 5 nm.

19. The method of Claim 17 or Claim 18, wherein the first or the second plurality of features se grooves.

20. . The method of any one of the Claims 17 to 19, wherein the second ion is d by an angle between about 1 degree and about 45 degrees with respect to the first direction. Knobbe, Martens

21. The method of any one of the Claims 17 to 20, wherein the imprint layer comprises a semiconductor material.

22. The method of any one of the Claims 17 to 21, wherein the liquid l layer comprises a polymerizable liquid crystal material.

23. The method of Claim 22, r comprising polymerizing the polymerizable liquid crystal material after the molecules of the polymerizable liquid crystal material are self-aligned to the first and the second plurality of features.

24. The method of Claim 23, wherein polymerizing the polymerizable liquid crystal material comprises exposing the polymerizable liquid crystal material to ultra-violet light.

25. The method of any of any one of the Claims 17 to 24, wherein the lens comprises a diffractive lens.

26. The method of any one of the Claims 17 to 25, wherein depositing a liquid crystal layer on the imprint layer comprises jet ting the liquid crystal.

27. The method of any one of the Claims 17 to 26, wherein a length or a width of the first plurality of features and the second plurality of es is less than or equal to about 100

28. The method of any one of the Claims 17 to 27, wherein a height or a depth of the first plurality of features and the second plurality of features is less than or equal to about 100 , Martens