Method for fabricating light guide optical elements

Abstract

The optical device is fabricated by obtaining at least one optical element and a frame. The at least one optical element is positioned within the frame according to a spatial configuration that defines the position of the at least one optical element within the frame and the orientation of the at least one optical element relative to the frame. The at least one optical element is bonded to the frame to fix the spatial configuration, and the area of ​​the frame not occupied by the at least one optical element is filled with a transparent optical material.

Description

[Technical Field]

[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Patent Application No. 63 / 521,409, filed on 16 June 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0002] This disclosure relates to an optical system, and more specifically, to a method for fabricating an optical device including a light guide optical element. [Background technology]

[0003] The optical arrangements of near-eye displays (NEDs), head-mounted displays (HMDs), and head-up displays (HUDs) require a large aperture to cover the area where the observer's (user's) eyes are located (commonly referred to as the eye movement box or EMB). To implement compact devices, the image projected onto the observer's eyes is generated by a small optical image generator (projector) with a small optical aperture. The image from the image projector is transmitted to the eyes by an optical combiner, which may be implemented as a light guide optical element (LOE) having one or more sets of parallel partially reflective inner surfaces, and the light guide optical element magnifies (multiplies) the image in one or two dimensions to generate a large aperture. [Overview of the Initiative]

[0004] This disclosure provides a method for fabricating an optical device including a light guide element (LOE).

[0005] A method for fabricating an optical device is provided according to the teachings of embodiments of the present disclosure. The method includes obtaining at least one optical element; obtaining a frame; arranging the at least one optical element within the frame according to a spatial configuration defining the position of the at least one optical element within the frame and the orientation of the at least one optical element relative to the frame; bonding the at least one optical element to the frame to fix the spatial configuration; and filling the area of ​​the frame not occupied by the at least one optical element with a transparent optical material.

[0006] Optionally, the method further includes arranging the frame between a pair of parallel surfaces, such that at least one optical element is located between the parallel surfaces, before filling the region of the frame with a transparent optical material.

[0007] Optionally, the method further includes curing a transparent optical material.

[0008] Optionally, at least one optical element is constructed from a material identical to the transparent optical material.

[0009] Optionally, at least one optical element is constructed from a glass material having a low glass transition temperature, or from a plastic or polymer material having a high glass transition temperature.

[0010] Optionally arranging at least one optical element within a frame involves deploying a device that arranges each of the at least one optical element according to the spatial configuration.

[0011] Optionally, at least one optical element has a material embedded inside the at least one optical element that is sensitive to at least one of an electric field or a magnetic field.

[0012] Optionally, disposing at least one optical element within the frame is at least partially effected by applying at least one of an electric field or a magnetic field to a material embedded within the at least one optical element.

[0013] Optionally, the embedded material comprises at least one of a ferromagnetic material or a dielectric material.

[0014] Optionally, the at least one optical element comprises a planar partially reflective surface.

[0015] Optionally, the at least one optical element comprises a lens.

[0016] Optionally, the at least one optical element comprises a polarizing beam splitter.

[0017] Optionally, the at least one optical element comprises an optical retarder.

[0018] Optionally, the at least one optical element comprises a reflective surface.

[0019] Optionally, the at least one optical element comprises a plurality of optical elements.

[0020] Optionally, the plurality of optical elements comprises a first plurality of planar partially reflective surfaces.

[0021] Optionally, the orientation defined by the spatial configuration is such that the first plurality of partially reflective surfaces are inclined obliquely with respect to a pair of parallel surfaces between which the frame is located.

[0022] Optionally, the orientation defined by the spatial configuration is such that the first plurality of partially reflective surfaces are perpendicular with respect to a pair of parallel surfaces between which the frame is located.

[0023] The orientation defined by the spatial configuration is such that the first set of partial reflective surfaces are parallel to each other.

[0024] Optionally, the method further includes obtaining a second plurality of planar partial reflective surfaces, and arranging the second plurality of partial reflective surfaces within a frame according to a second spatial configuration that defines the positions of the second plurality of partial reflective surfaces within the frame and the orientation of the second plurality of partial reflective surfaces relative to the frame, wherein the orientation defined by the second spatial configuration is such that the second plurality of partial reflective surfaces are parallel to each other and non-parallel to the first plurality of partial reflective surfaces.

[0025] Optionally, at least one optical element includes a plurality of planar partial reflective surfaces, and obtaining at least one optical element includes obtaining a production plate formed from glass having a low glass transition temperature or a plastic or polymer material having a high glass transition temperature, coating the production plate with a partial reflective coating, and slicing the coated production plate to produce a plurality of coated plates, each coated plate being a planar partial reflective surface.

[0026] Optionally, at least one optical element includes a plurality of planar partial reflective surfaces, and obtaining at least one optical element includes obtaining a plurality of generating plates, each generating plate being formed from glass having a low glass transition temperature or a plastic or polymer material having a high glass transition temperature; coating each of the generating plates with a partial reflective coating; stacking the coated generating plates in a laminate and temporarily joining the coated generating plates together with a temporary adhesive; slicing the laminate and removing the temporary adhesive to produce a plurality of coated plates, each coated plate being a planar partial reflective surface.

[0027] Selectively obtaining at least one optical element includes obtaining a certain amount of material that is sensitive to at least one of an electric field or a magnetic field, and embedding that amount of material into an optical material to form at least one optical element.

[0028] Methods for fabricating optical devices are also provided according to the teachings of embodiments of the present disclosure. The method includes obtaining at least one optical element; obtaining a block of transparent material, the block of transparent material having at least one opening, wherein at least one opening and at least one optical element are configured in correspondence, and each opening of the at least one opening is an internal surface of the block having a spatial configuration that defines the position of the internal surface within the block and the orientation of the internal surface with respect to the external surface of the block; inserting each optical element of the at least one optical element into a corresponding opening of the at least one opening; and joining each optical element of the at least one optical element into the corresponding opening.

[0029] Optionally, the method further includes arranging a block between a pair of parallel surfaces such that at least one optical element is located between plates, and filling the area between the parallel surfaces and the block with a transparent filler material.

[0030] Optionally, the transparent filler material includes at least one of an optical adhesive or an index matching liquid.

[0031] Optionally, the transparent material is glass with a low glass transition temperature, or a plastic or polymer material with a high glass transition temperature.

[0032] Optionally, at least one optical element is constructed from glass having a low glass transition temperature, or from a plastic or polymer material having a high glass transition temperature.

[0033] Optionally, at least one optical element includes a planar partial reflective surface.

[0034] Optionally, at least one optical element includes a lens.

[0035] Optionally, at least one optical element includes a polarizing beam splitter.

[0036] Optionally, at least one optical element includes an optical retarder.

[0037] Optionally, at least one optical element includes a plurality of planar partial reflective surfaces.

[0038] Optionally, at least one opening includes a plurality of openings defining a plurality of first internal surfaces, and an orientation of the first internal surfaces defined by the spatial configuration such that the first internal surfaces are parallel to each other.

[0039] Optionally, at least one optical element includes a first plurality of planar partial reflective surfaces, and a block of transparent material has a second plurality of openings, each of which is a second internal surface of the block. A method for defining a second internal surface of a block having a second spatial configuration that defines the position of the second internal surface within the block and the orientation of the second internal surface with respect to the external surface of the block, wherein the orientation of the second internal surface is defined by the second spatial configuration such that the second internal surface is parallel to each other and non-parallel to the first internal surface, and the method for obtaining a second plurality of planar partial reflections, wherein a second plurality of openings and a second plurality of partial reflection surfaces are configured in correspondence, the method further includes inserting each partial reflection surface of the second plurality of partial reflection surfaces into a corresponding opening of a second plurality of elongated openings, and joining the partial reflection surfaces of the second plurality of partial reflection surfaces into the openings of the second plurality of openings.

[0040] Optionally, obtaining a block of transparent material includes obtaining a solid block of transparent material and removing at least a portion of the solid block to create at least one opening.

[0041] Throughout this book, optical materials are referred to as low-refractive-index materials, medium-refractive-index materials, and high-refractive-index materials. In the context of this book, an optical material is considered a high-refractive-index material if its refractive index is approximately 1.7 or higher. In the context of this book, an optical material is considered a low-refractive-index material if its refractive index is within the range of approximately 1 to approximately 1.53. In the context of this book, an optical material is considered a medium-refractive-index material if it is neither a low-refractive-index material nor a high-refractive-index material, in other words, if its refractive index is within the range of approximately 1.53 to 1.7.

[0042] Unless otherwise defined herein, all technical and / or scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to whom this disclosure relates. Similar or equivalent methods and materials may be used in carrying out or testing embodiments of this disclosure, but exemplary methods and / or materials are described below. In case of any conflict, the patent specification, including definitions, shall prevail. In addition, materials, methods, and examples are illustrative and not necessarily intended to be limiting. [Brief explanation of the drawing]

[0043] Some embodiments of the present disclosure are described herein merely as examples with reference to the accompanying drawings. It should be emphasized that any specific references to the drawings are provided as examples and for illustrative purposes of the embodiments of the present disclosure. In this regard, the specification, made in conjunction with the drawings, will make it clear to those skilled in the art how embodiments of the present disclosure may be carried out.

[0044] Now, if we turn our attention to the drawings, in the drawings, similar reference numbers or letters indicate corresponding or similar components.

[0045] [Figure 1] This is a schematic side view illustrating an optical device in the form of light guide optics (LOE), which can be fabricated using a method according to an embodiment of the present disclosure, having a set of main external surfaces and a set of mutually parallel partially reflective internal surfaces inclined obliquely with respect to the main external surfaces to achieve one-dimensional aperture expansion. [Figure 2] This is a schematic diagram of an optical device in the form of a Loom of Energy (LOE), which can be fabricated using the method according to the embodiments of the present disclosure, having first and second sets of mutually parallel partially reflective inner surfaces, wherein the orientation of the first set of surfaces is nonparallel to the orientation of the second set of surfaces in order to achieve two-dimensional aperture expansion. [Figure 3] Figures 3A to 3N illustrate the steps for fabricating an optical device to be implemented as a Line of Engineering (LOE) according to an embodiment of the present disclosure. [Figure 4] This disclosure illustrates a robotic device that can be used to position a partially reflective surface as part of the fabrication step of an optical device. [Figure 5] This is a schematic diagram of a device implemented as an optical test bench apparatus that can be used to position a partially reflective surface as part of the fabrication step of a LOE according to embodiments of the present disclosure. [Figure 6] This invention schematically illustrates an arrangement that can be used for mass production of optical devices according to the embodiments of this disclosure. [Figure 7] Figures 7A to 7C illustrate the steps for manufacturing a partially reflective surface according to an embodiment of the present disclosure. [Figure 8] Figures 8A–8F illustrate steps for manufacturing a partially reflective surface according to another set of embodiments of the present disclosure. [Figure 9] Figures 9A to 9F illustrate steps for mass-producing partially reflective surfaces according to yet another set of embodiments of the present disclosure. [Figure 10]This is a schematic diagram of a device that can be used as part of the fabrication step of a Loom of Energy (LOE) to position a partially reflective surface having an embedded magnetic material and / or dielectric material by applying an electric field and / or magnetic field to the partially reflective surface, according to an embodiment of the present disclosure. [Figure 11] Figures 11A–11D illustrate the steps for fabricating an optical device to be implemented as a Line of Engineering (LOE) according to another set of embodiments of the present disclosure. [Figure 12] Figures 12A–12C illustrate the steps for fabricating a LOE according to yet another set of embodiments of the present disclosure. [Figure 13] Figures 13A and 13B illustrate the steps for fabricating a LOE according to a further set of embodiments of the present disclosure. [Figure 14] This graph shows the reflectance curves for p-polarized and s-polarized light in a specific angular range of 40° to 60°. [Modes for carrying out the invention]

[0046] Certain embodiments of this disclosure provide a method for fabricating a LOE.

[0047] The principles and operation of the methods described herein can be better understood by referring to the drawings accompanying this specification.

[0048] Before describing in detail at least one embodiment of this disclosure, it should be understood that in its application, this disclosure is not necessarily limited to the structural and arrangement and / or method details of the components described below and / or illustrated in the drawings and / or examples. Other embodiments of this disclosure are possible, or it can be practiced or implemented in various ways.

[0049] Firstly, Figures 1 and 2 illustrate a particular, especially preferred embodiment of an optical device to which the fabrication method of this disclosure is particularly relevant, but the fabrication method is not limited to such applications.

[0050] Figure 1 schematically illustrates an exemplary mounting configuration of an optical device generally designated 10 employing the LOE (also referred to as the “substrate”) 12 according to this disclosure. The LOE 12 is formed from a transparent (i.e., light-transmitting) material and includes a set (pair) of parallel main external surfaces 14, 16 and a set (pair) of parallel planar partial reflective surfaces (“facets”) 18. The facets 18 are located inside the LOE 12, i.e., they are located between the main external surfaces 14, 16 and are inclined obliquely with respect to the main external surfaces 14, 16. A compact image projector 20 injects image illumination (corresponding to a collimated image) 19 into the LOE 12 and is optically coupled to the LOE 12 via a preferred optical coupling configuration 22 (represented in the drawings as a coupling prism, but may be in other preferred forms such as a coupling reflector) such that the image light is captured by internal reflection at the main external surfaces 14, 16. The propagating image light (represented as ray 24) interacts with facet 18, which gradually deflects (couples out) a portion of the image illumination (represented as ray 30) from LOE 12 towards the observer's eye 26 located within the region defined as the eye movement box (EMB) 28, thereby achieving a one-dimensional expansion of the optical aperture.

[0051] Figure 2 illustrates another exemplary implementation of the optical device according to the disclosure, employing LOE 12' to achieve two-dimensional aperture expansion. Here, LOE 12' comprises two regions designated 13 and 15, each having its own set of facets 17 and 18 having its own orientation. The main external surfaces 14, 16 extend across the two regions 13 and 15 such that both sets of facets 17 and 18 are located between the main external surfaces 14, 16. Most preferably, the main external surfaces 14, 16 are a pair of surfaces that are each continuous across the entirety of the two regions 13 and 15, although options having a set-down or increasing thickness between regions 13 and 15 are also within the scope of the disclosure. Regions 13 and 15 may be juxtaposed in close proximity so as to meet at a boundary that may be a linear boundary or some other form of boundary, or there may be one or more additional LOE regions interposed between them to provide various additional optical or mechanical functions, depending on the particular application. Although this disclosure is not limited to any particular manufacturing technique, in certain particularly preferred configurations, a particularly high-quality main outer surface can be achieved by employing a continuous outer plate in which separately formed regions 13 and 15 are sandwiched between them to form a composite LOE structure.

[0052] In Figure 2, the compact image projector 20 injects image illumination into the LOE region 13 via a coupling prism 22 and is optically coupled with LOE 12' so that the image light is captured (propagates) within the LOE region 13 by internal reflections at the main outer surfaces 14 and 16. The propagating image illumination (ray 24) collides with facets 17 in region 13 and is also captured / guided by internal reflections within LOE 12', with each consecutive facet deflecting a portion of the image illumination in the deflection direction. These partial reflections at the consecutive facets achieve a first-dimensional optical aperture expansion. In a first set of preferred but non-limiting embodiments of the present disclosure, the set of facets 17 in region 13 is orthogonal to the main outer surface of LOE 12'. In this case, both the injected image and its conjugate, which undergoes internal reflections as it propagates within region 13, become a deflected and propagating conjugate image. In an alternative set of preferred but non-limiting embodiments, facet 17 is angled obliquely to the main external surface. In the latter case, either the injected image or its conjugate forms a desired deflected image propagating within the LOE 12', while other reflections can be minimized, for example, by employing an angle-selective coating on the facet that makes the facet relatively transparent to the range of incident angles presented by images for which reflection is not desired.

[0053] Facet 17 has an orientation that is nonparallel to the orientation of facet 18 and is specifically oriented so that a portion of the image illumination 24 propagating within the LOE 12' by internal reflection at the main external surfaces 14, 16 from the coupled input region (coupled prism 22) is deflected from region 13 toward region 15 (into region 15). The deflected image illumination from region 13 (represented as rays 25) then enters another region 15, which can be mounted as an adjacent separate substrate or as an extension of a single substrate. Facet 18 is oriented such that facet 18 is obliquely tilted with respect to the main external surfaces 14, 16, and gradually couples out a portion of the image illumination 25 propagating within the LOE 12' by internal reflection at the main external surfaces 14, 16 from region 13 toward region 15 toward the observer's eye located within the EMB 28, thereby achieving a second-dimensional optical aperture expansion. The coupled-out illumination is represented as rays 30.

[0054] Conventional methods for generating LOEs typically rely on the steps of coating a transparent plate (referred to as the “generating plate”) with a partial reflective coating, then laminating the coated plates, and joining the laminated plates together. To generate an LOE that achieves one-dimensional aperture expansion, such as the LOE illustrated in Figure 1 (a “1DLOE”), the joined laminate is then cut along a series of parallel cutting planes angled to the outer surface of the laminate to extract the 1DLOE. The angle of the cutting planes defines the oblique inclination angle of the facets of the final LOE product. Examples of 1DLOE generating methods are described in detail in various patent publications by Lumus Ltd. (Israel), including, for example, U.S. Patent No. 8,873,150, PCT Publication WO2016 / 103263, and PCT Publication WO2020 / 212835, which are incorporated herein by reference in their entirety.

[0055] To generate a LOE ("2DLOE") that achieves two-dimensional aperture expansion, such as the LOE illustrated in Figure 2, a similar laminate of coated plates is formed and then bonded to a bonded laminate of 1DLOE such that the coated plates of the second laminate and the facets of the 1DLOE are non-parallel to each other. The bonded structure is then cut along a series of parallel cutting planes, typically parallel to the main surface of the 1DLOE, to extract the 2DLOE. Examples of conventional 2DLOE generation methods are described in detail in various patent publications by Lumus Ltd. (Israel), including, for example, PCT Publication WO2021 / 240513, PCT Publication WO2021 / 152602, PCT Publication WO2021 / 001841, and U.S. Patent No. 10,551,544, which are incorporated herein by reference in their entirety.

[0056] In the method described above, the lamination and bonding steps are performed under tight optical tolerances to ensure parallelism between facets and between main outer surfaces. In addition, including uncoated elements such as optical retarders, polarizing beam splitters, perfect reflective surfaces (i.e., mirrors), and lenses within the LOE presents manufacturing challenges when employing conventional methods, as each of these elements must typically withstand the demanding lamination and bonding fabrication steps, while adding time-consuming optical testing to ensure that the uncoated elements are not damaged during fabrication and still function properly optically.

[0057] Certain embodiments of the present disclosure provide a method for fabricating optical devices including LOEs that do not rely on laminating and bonding of generated plates. Rather, as will be described, these embodiments rely on the arrangement of partially reflective surfaces fabricated within a frame structure or optical structure having correspondingly configured apertures. Other embodiments of the present disclosure also rely on laminating and bonding of plates, but do not employ coated plates, but rather employ a high refractive index optical adhesive spread between optical plates of lower refractive index to achieve the partially reflective function. The advantages of the fabrication methods of the present disclosure will become apparent from the following description.

[0058] Referring here to Figures 3A to 3N, a method for fabricating an optical device that may be a LOE is illustrated according to a non-limiting exemplary embodiment of the present disclosure. In the illustrated embodiment, a frame member 102, which is preferably a hollow (i.e., empty) frame, is obtained, as shown in the top and side views of Figures 3A and 3B. The frame member 102 is a carrier member configured to have at least one optical element bonded (as will be considered below), and may be a rigid member that can be constructed from any suitable material, such as plastic or aluminum, or a material with a low coefficient of thermal expansion (such as Zerodur®, commercially available from Schott AG in Munich, Germany), to ensure that the bonded optical element remains in place during the remaining steps of the fabrication process (which may include a heat treatment step) after bonding. In the non-limiting embodiments illustrated in the drawings, the frame 102 includes first and second pairs of planar (rectangular) parallel side walls 101a, 101b, 109a, 109a, 109b such that the frame 102 has a rectangular cross-section in a plane (i.e., the plane of paper) perpendicular to the side walls 101a, 101b, 109a, 109a, 109b. The top and bottom of the hollow opening of the frame 102 are bounded by the first and second parallel planes 103a and 103b, respectively. Although the frame 102 is shown in the drawings as having a rectangular cross-section and being formed from rectangular side walls, the frame can be constructed using various side wall arrangements and geometric shapes, including, for example, polygonal or non-polygonal side walls. For example, embodiments in which the frame is formed from curved side walls such that the frame has a non-polygonal cross-section in the plane of paper are contemplated herein.

[0059] As illustrated in the top and side views of Figures 3C and 3D, at least one optical element 104 is also obtained. In non-limiting exemplary embodiments, at least one optical element 104 is implemented as a set(s) of planar partial reflective surfaces (hereinafter referred to as "facets"). The facets 104 may preferably be constructed from a base element such as an optical plate having a partially reflective coating applied to it, and having equal size and dimensions. In certain embodiments, all facets are formed from a base element having a partially reflective coating applied to one side of the base element (referred to as one-side or single-side coated facets). In other embodiments, each facet of a first subset of facets is formed from a base element having a partially reflective coating applied to both sides of the base element (referred to as a double-sided coated facet), and each facet of a second subset of facets is formed from an uncoated base element (referred to as an uncoated facet).

[0060] Examples of methods for constructing facets will be described in subsequent sections of this disclosure.

[0061] Incidentally, the embodiments illustrated in Figures 3A to 3N will be described in the context that at least one optical element 104 is a set of facets, but at least one optical element 104 may be implemented as one or more other types of coated optical elements, such as reflective surfaces (i.e., mirrors), and / or lenses, polarizing beam splitters, optical retarders (e.g., waveplates), including but not limited to these, one or more types of uncoated optical elements.

[0062] Referring here to Figures 3E and 3F, which show a top view and a side view, respectively, the optical element 104 is arranged within the frame 102 according to a spatial configuration, preferably a predetermined spatial configuration. The spatial configuration of the optical element 104 within the frame 102 defines the position (location) of the optical element 104 within the frame 102 and the orientation of the optical element 104 with respect to the frame 102. The orientation includes angular orientation in three-dimensional space, and in the case of facets 104, it may include the three angles of the plane of each facet with respect to the central plane of the frame 102. In embodiments in which the optical device under construction is LOE, the orientation of the facets 104 defined by the spatial configuration is such that the facets 104 are parallel to each other. In certain embodiments, the spatial orientation of the facet 104 is preferably such that the first long side (i.e., end, edge) 105a of the facet 104 is bounded by a first boundary plane, and the second long side (end or edge) 105b of the facet 104 is bounded by a second boundary plane parallel to the first boundary plane. The first and second boundary planes (which each define the first and second long sides 105a and 105b) may be parallel to planes 103a and 103b, or they may be non-parallel to planes 103a and 103b.

[0063] Once the facets 104 are positioned according to the spatial configuration, they are joined to the frame 102 to fix the spatial configuration. Throughout this specification, the terms “joined” or “joined” should be understood to mean being attached using an adhesive / seal, which may be an optical adhesive (also referred to as optical cement or optical glue), depending on the specific case. For example, the adhesive used to join the facets 104 to the frame 102 does not necessarily have to be an optical adhesive, while the adhesive used in the embodiments described with reference to Figures 11A–11D may or may not be an optical glue.

[0064] In certain embodiments, the adhesive used to bond the facet 104 to the frame 102 requires activation or crosslinking by ultraviolet (UV) curing (e.g., via a UV lamp), oxygen curing, thermal curing (e.g., via a heat lamp), or several other preferred forms of curing. Accordingly, according to certain embodiments, the adhesive is applied to the interface region between the facet 104 and the frame 102, e.g., the short sides (ends or edges) 107a and 107b) of the facet 104, and then cured using appropriate curing means. Figures 3G and 3H (top view and side view, respectively) show the amount of adhesive 106 applied to the interface region between the facet 104 and the frame 102 before curing, and Figures 3I and 3J show the cured adhesive 108. The drawings show that adhesive 106 / 108 is applied to the entire short sides 107a and 107b of facet 104, but it should be noted that the adhesive may be applied to only a portion of the short sides 107a and 107b. Furthermore, the drawings show that adhesive 106 / 108 is applied to both the short sides 107a and 107b of each facet 104, but in some cases the adhesive may be applied to the entire or partial side of only one of the short sides of each facet.

[0065] In certain embodiments, all facets 104 may be arranged according to the spatial configuration and then joined to the frame 102. In other embodiments, facets may be arranged and joined one at a time. For example, a first facet may be arranged within the frame according to the spatial configuration, then glue / adhesive may be applied between the first facet and the frame to fix the spatial configuration, and then the glue / adhesive may be cured. Then the next facet may be arranged and joined, and so on.

[0066] Once all facets 104 are joined to the frame 102, the spatial configuration of facets 104 is fixed, so that the facets are parallel to each other. The areas of the frame not occupied by facets 104 are then filled with a transparent optical material that forms the bulk of the fabricated optical device. The unoccupied areas are represented as 110 in the side view of Figure 3J, and the transparent optical material that fills the previously unoccupied areas 110 is represented as the dotted area 112 in Figure 3K. In a particular preferred embodiment, facets 104 are constructed from the same material as the transparent optical material 112 that fills the frame 102.

[0067] The transparent optical material 112 may be, for example, a plastic, glass, or polymer resin that can be injected into the region 110 via any suitable injection means. The injected resin 112 can then be cured to solidify / harden, for example, by UV and / or heat curing (e.g., via a UV lamp and / or heat lamp), thereby forming the bulk of the optical device.

[0068] To support light propagation by internal reflection, the LOE requires parallelism between a pair of main outer surfaces. To produce an LOE with parallel main outer surfaces, the frame 102 is preferably positioned between a pair of parallel surfaces 114a and 114b such that facet 104 is located between the parallel surfaces 114a and 114b before the unoccupied region 110 is filled with transparent optical material. This is illustrated in Figure 3L (side view). The parallel surfaces 114a and 114b can be implemented, for example, as a pair of parallel transparent glass or plastic plates, or opaque carrier plates.

[0069] Figure 3M is similar to Figure 3L, but shows uncured transparent optical material 112 filling previously unoccupied areas. Figure 3N shows post-curing of the transparent optical material, represented as cross-hatching 112'.

[0070] After the transparent optical material 112' has hardened, the frame and surfaces (e.g., plates) 114a and 114b can be removed to expose the fabricated optical device having the embedded optical element 104. The main outer surface of the optical device can then be optically polished. In some cases, for example, if the frame does not optically interfere with the optical function of the optical device, the fabricated optical device can be left in the frame.

[0071] In certain embodiments, the facets may be arranged according to an alternating double-sided coated and uncoated configuration, such that each double-sided coated facet is adjacent to an uncoated facet, and each uncoated facet is adjacent to a double-sided coated facet. Such a configuration can achieve results similar to the alternating configuration described in PCT Publication WO2020 / 212835.

[0072] As should be obvious, the optical performance of an optical device largely depends on the proper arrangement of the optical elements 104 according to a suitable spatial configuration. In practice, misalignment of optical elements can lead to a decrease in optical performance. Various methods can be used to arrange the facets (or optical elements in general) 104 with high precision within the frame 102 according to a spatial configuration. According to a particular embodiment of this disclosure, the device is unfolded to arrange the facets 104 according to a spatial configuration.

[0073] In one set of non-limiting embodiments, the device is implemented as a surface mount technology (SMT) component placement system, commonly referred to as a pick-and-place machine, which is typically a robotic machine having one or more robotic arms controlled by a hardware processing unit, and having one or more computerized processors coupled to one or more computerized storage devices (e.g., memory) that store program code for controlling the robotic arms. The robotic machine typically employs an optical system that performs calculations regarding the spatial position and orientation of the devices being placed. These robotic machines are common in the semiconductor industry for high-speed, high-precision placement of electronic components on printed circuit boards and are commonly available from companies such as Fuji, Panasonic, Yamaha, and Hitachi. Figure 4 illustrates a particular example of a pick-and-place robot 120, available from Mecademic of Canada, having a robotic arm 122, which can be used to place optical elements, e.g., facets 104, within a frame 102 with high precision according to the spatial configuration. The specific pick-and-place robot illustrated in Figure 4 is one non-limiting example of a pick-and-place robot that may be used in embodiments of this disclosure.

[0074] In another set of non-limiting embodiments, for example, as illustrated in Figure 5, the device is implemented as an optical test bench apparatus (commonly referred to as a “jig”) 130 for arranging and aligning optical components. The jig 130 includes a frame holder 132 and an optical element placement apparatus 140.

[0075] The frame holding device 132 may include a frame holder 133 for holding the frame 102. The frame holder 133 may be mechanically coupled (e.g., mounted) to a rotatable stage 134 that provides adjustment of the yaw angle of the frame 102. The rotatable stage 134 may be mechanically coupled (e.g., mounted) to a roll goniometer 136 that provides adjustment of the roll angle of the frame 102. The roll goniometer 136 may be mechanically coupled (e.g., mounted) to a pitch goniometer 138 that provides adjustment of the pitch angle of the frame 102. Components 134, 136, and 138 provide multiple degrees of freedom for positioning / orientation of the frame 102.

[0076] The optical element placement device 140 may include a mechanical arm 142 for positioning optical elements (facets) 104 within a frame 102. The mechanical arm 142 may be mechanically coupled (e.g., mounted) (e.g., via a rod 143) to a rotatable stage 144 that provides adjustment of the yaw angle of the mechanical arm 142. The rotatable stage 144 may be mechanically coupled (e.g., mounted) to a roll goniometer 146 that provides adjustment of the roll angle of the mechanical arm 142. The roll goniometer 146 may be mechanically coupled (e.g., mounted) to a pitch goniometer 148 that provides adjustment of the pitch angle of the mechanical arm 142. The pitch goniometer 148 may be mechanically coupled (e.g., mounted) to a positioning stage 149 that provides lateral movement of the placement device 140. Components 144, 146, 148, and 149 provide multiple degrees of freedom for the positioning and orientation of the mechanical arm 142.

[0077] The jig 130 may further include an autocollimator 150 and an imaging device (camera) 152 that can be used to measure the spatial position and orientation of the optical elements relative to the frame. The combination of components of the jig 130 enables the jig 130 to position the optical elements within the frame with high precision according to the required spatial configuration.

[0078] In certain embodiments, the frame 102 may include a structure that provides temporary retention of facets according to the required spatial configuration. For example, according to certain embodiments, the frame 102 may include one or more pairs of channels or grooves (one pair per facet) that define the spatial configuration of the facets. The facets and channels / grooves are configured in correspondence such that the facets can be retained within the frame by being placed within the channels or grooves, thereby allowing the facets to be temporarily retained within the frame before bonding and filling of the transparent optical material.

[0079] In certain embodiments, optical element magazines can be used to temporarily store optical elements in a temporary spatial configuration before they are placed in the frame 102, and the magazines can be positioned relative to the frame so that the optical elements are positioned relative to their final positions when stored in the magazines, and as a result, the optical elements can be quickly dumped into the frame in the correct spatial configuration. Such embodiments are particularly useful, for example, for the mass production of optical devices in an assembly line. Figure 6 illustrates an embodiment employing multiple facet magazines 160, each temporarily storing a set of facets 104 to be placed in a corresponding frame. In the figure, the first frame 102a is completed (i.e., all facets 104a in frame 102a are properly placed and joined), the next frame 102b is being filled by one of the facet magazines 160 (i.e., some of the facets 104b are properly placed and joined), and the next frame 102c is empty and awaiting filling from another of the facet magazines 160.

[0080] The methods described herein are suitable for producing various types of optical devices, including, exemplarily, LOEs that may be 1DLOEs such as the LOE illustrated in Figure 1, and 2DLOEs such as the LOE illustrated in Figure 2. The spatial configuration of facets within the frame can be selected according to the type of LOE and the required position and orientation of the facets in the final LOE product. For example, when constructing a 1DLOE or 2DLOE where facet 104 will become facet 18 in the final LOE product, facet 104 should be positioned within the frame 102 such that the orientation of the facets defined by the spatial configuration is such that facet 104 is parallel to each other, and preferably, facet 104 is obliquely inclined with respect to a pair of parallel surfaces 114a and 114b, or planes 103a and 103b, between which the frame lies. As another example, when constructing a 2DLOE where facet 104 will become facet 17 in the final LOE product, facet 104 may be positioned within the frame 102 such that the orientation of the facets defined by the spatial configuration is such that facet 104 is parallel to one another, and optionally facet 104 is inclined obliquely to a pair of parallel surfaces 114a and 114b, or planes 103a and 103b, or facet 104 is perpendicular to a pair of parallel surfaces 114a and 114b, or planes 103a and 103b. When constructing a 2DLOE, a first set of facets 104 (corresponding to facet 18) may be arranged according to a first spatial configuration such that they are parallel to each other and inclined obliquely with respect to a pair of parallel surfaces 114a and 114b or planes 103a and 103b, and a second set of facets 104 (corresponding to facet 17) may be arranged according to a second spatial configuration such that they are parallel to each other and have an orientation (defined by the second spatial configuration) that is non-parallel to the orientation of the first set of facets.

[0081] As described above, in certain embodiments, the same type of optical material is used to fabricate the facets and fill the frame. In other words, in certain embodiments, the bulk of the facets and the optical device are formed from the same material. In a preferred embodiment, this material is a low density material, which provides the additional advantage that the final optical device (e.g., LOE) product is lighter than conventional LOEs. Examples of types of low density materials include plastics, certain types of glass, and polymers. As described above, when such materials are used as the bulk of the LOE, they can be injected as a resin and then cured to solidify.

[0082] One class of optical materials that provide certain advantages when used in the fabrication methods discussed above are materials that have a low or high glass transition temperature (T g ), specifically, low T g glass and high T g plastic / polymer materials. The terms "low" and "high" are defined herein within the specific context of the types of materials that are "low" or "high" in T g . For example, in the case of plastic or polymer materials, "high" T g is defined herein as being greater than about 100°C. In the case of glass, "low" T g is preferably defined as about 380°C, although in some cases, for example, when an oxide coating is used to produce partial reflectivity of the glass facets, glasses having a higher T g , e.g., about 560°C or even higher Tg, are acceptable. In addition to being low density and thus lightweight, one advantage of using high T g plastics / polymers in the LOE fabrication method is that less material is wasted during the fabrication process (compared to the materials used in conventional LOE fabrication methods). In certain embodiments, both the facets themselves and the optical material used to fill the frame after the facets are joined to the frame are made from the same low or high T g material. In such embodiments, the frame has a low or high Tg After being filled with optical material (resin), the optical device under fabrication is T to reduce birefringence and increase the overall refractive index uniformity of the optical device. g It can be heated to a temperature close to . Suitable for low or high T for constructing facets and filling the frame. g As for materials, for example, T g A cycloolefin polymer (COP) having 130°C to 180°C g A cycloolefin copolymer (COP) having low T g One example is the P-PK53 glass.

[0083] Referring now to Figures 7A to 7C, a non-limiting exemplary embodiment of the present disclosure illustrates a low or high T g This document describes methods for constructing facets from materials.

[0084] Referring particularly to Figure 7A, low or high T g A production plate 170 formed from a transparent material having [a certain characteristic] is obtained and coated on one side with a partial reflective coating 172. The plate 170 is, for example, coated when the temperature of the coating 172 is T g Coating 172 can be cold coated by a physical vapor deposition coating process or by a sputtering coater, if the T is less than 1. Alternatively, plate 170 can be cold coated by a physical vapor deposition coating process or by a sputtering coater. g Glass or high Tg plastics / polymers, or even higher T g Glass (for example, T in the range of 120°C to 600°C) g Glass having a temperature of approximately 557°C, for example, T g It can be coated using a sacrificial layer 174 on a substrate / plate of BK7 glass (which has a higher T). g From the plate, the final low or high T gIt can be used to replicate onto a plate. In an embodiment in which a sacrificial layer 174 is deposited on a plate 170 and then the sacrificial layer 174 is coated with a coating 172, an optionally thick layer of optical adhesive can be applied to the coating layer 172 and then the sacrificial layer 174 can be removed. As an additional option, a partial reflective coating 172 can be applied to both sides of the plate 170 to create a double-sided coated facet.

[0085] In certain embodiments, the coated 170 may be sized and dimensioned to produce a single facet. In other embodiments, for example, as shown in Figure 7B, the coated plate 170 may be sized and dimensioned to produce multiple facets, and the coated plate 170 may be sliced ​​(cut) along a set of cutting planes to produce multiple smaller coated plates, each smaller coated plate being a facet 104 (corresponding to facet 104). In Figure 7B, the coated plate 170 is cut along a set of five cutting planes, four of which are parallel to each other and evenly spaced, and a fifth cutting plane 178 is perpendicular to the plane 176, thereby producing 10 facets 104.

[0086] For larger-scale generation of facets 104, multiple coated plates 170 (e.g., each having or not having a sacrificial layer 174 as shown in Figure 7A) can be generated and then arranged in a laminate 180, for example, as illustrated in Figure 7C. The plates 170 within the laminate 180 can be temporarily bonded together using a temporary adhesive 182 layered between the coating 172 of one plate and the uncoated surface of an adjacent plate 170, for example. The laminate 180 can then be cut along a set of cross-sections similar to those in Figure 7B to generate multiple laminates of smaller-sized coated plates. The temporary adhesive between the coated plates within each laminate can then be removed to separate the individual smaller-sized coated plates, each of which is a facet.

[0087] Referring here to Figures 8A to 9F, a method for fabricating facets is described according to another non-limiting exemplary embodiment of the present disclosure, where each facet has an embedded material within the facet that is sensitive to at least one of an electric field or a magnetic field. The embedded material may be a magnetic material, such as one or more ferromagnetic particles, and a dielectric material. The facet bulk material may be any optical material exhibiting partial reflectivity, such as optical glue, glass, plastic, or polymer.

[0088] Referring particularly to Figure 8A, a certain amount of embedded material 190 (implemented as a ferromagnetic material in this example) is placed on a carrier plate 192, which is preferably a flat plate. A magnet (not shown) can be used to move the ferromagnetic material 190 to the desired position on the carrier plate 192. Then, as shown in Figure 8B, a certain amount of faceted bulk material (represented in the figure as a dotted region 194), for example, optical glue, is placed on the carrier plate 192 such that the ferromagnetic material 190 is embedded within the bulk material 194, i.e., inside the bulk material 194. Optionally, as illustrated in Figure 8C, another flat plate 192a can be placed on the bulk material 194 such that the bulk material 194 having the embedded ferromagnetic material 190 is sandwiched between plates 192 and 192a. Plates 192 and 192a can be pressed together, thereby helping to flatten the bulk material 194 to the desired thickness. Next, the bulk material 194 can be cured, for example, by UV and / or thermal curing (e.g., via a UV lamp and / or heat lamp) so that it solidifies / hardens. Figure 8D shows the post-curing of the bulk material, represented as cross-hatching 194'.

[0089] Once the bulk material has cured, the top flat plate 192a can be removed, and then, as shown in Figure 8E, a portion of the cured material having an embedded ferromagnetic material 190 is removed from the carrier plate 192 to form facets 104. Optionally, facets 104 can be reduced in size and / or dimensions, as shown in Figure 8F. In certain embodiments, one or more coating layers 195, e.g., thin film coatings (which may be multilayer coatings) and / or one or more optical sheets (e.g., available from 3M), can be applied to the cured bulk material 194' before or after removal from the carrier plate 192, and before or after reducing the size and / or dimensions of the facets. The coating layer 195 may be a partially reflective coating that provides the facets 104 with their partial reflectivity. In other embodiments, the partial reflectivity of the facets may be achieved by using a high-refractive-index or medium-refractive-index optical adhesive as the facet bulk material 194', and by using a lower refractive index material (either a medium-refractive-index material or a low-refractive-index material) as the LOE bulk material. Embedding a high-refractive-index material within a lower-refractive-index bulk LOE material to influence the partial reflectivity of the facets will be discussed in more detail below with reference to Figures 13A and 13B in the context of another embodiment.

[0090] Here, as can be seen with reference to Figures 9A to 9F, the production method illustrated in Figures 8A to 8F can be extended for the production of larger facets. In Figure 9A, multiple particles of ferromagnetic material 190 are placed on a carrier plate 192 and can be aligned and distributed to the desired positions via a magnet. Figure 9B shows the aligned ferromagnetic material 190 on the carrier plate 192. Figure 9C shows optical adhesive 194 (or other suitable partial reflective bulk material) placed on the carrier plate 192 so that the aligned ferromagnetic material 190 is embedded in the optical adhesive 194. As discussed above, the bulk material 194 can be sandwiched between the carrier plate 192 and another flat plate to flatten the bulk material 194 to a desired thickness. The optical adhesive 194 can then be cured as discussed above. Figure 9D shows the post-curing of the optical adhesive 194'. Once the optical adhesive has cured, the cured material 194' having the internally embedded and aligned ferromagnetic material 190 is removed from the carrier plate 192, as shown in Figure 9E, and then cut to form individual facets 104, each having the internally embedded ferromagnetic material, as shown in Figure 9F. In embodiments where the partial reflectivity of the facets is achieved by a partial reflective coating, a thin film coating and / or one or more optical sheets can be applied to the cured bulk material 194' before or after removal from the carrier plate 192 (as described above and shown in Figure 8F), preferably before the cured bulk material 194' is cut to form individual facets.

[0091] In certain embodiments, a certain amount of dielectric material can be embedded in the facets in addition to, or instead of, the ferromagnetic material. The embedding can be achieved using the same or similar techniques described above for embedding the ferromagnetic material.

[0092] According to certain embodiments, the orientation of the embedded magnetic and / or dielectric material can be adjusted before the curing of the bulk material.

[0093] Using the processes described with reference to Figures 8A to 9F, multiple very small partial reflectors, or faceted fragments, can be fabricated. In certain embodiments, a group of faceted fragments may be oriented within the bulk material to function as a single, standalone faceted structure. In such embodiments, the faceted fragments of the group (each having embedded magnetic and / or dielectric material) may be oriented at an angle before the bulk material is compressed.

[0094] The embodiments discussed above with reference to Figures 8A to 9E were described in the context of non-limiting examples where the faceted bulk material is a high-refractive-index or medium-refractive-index optical glue. However, embodiments in which other materials are used to form the faceted bulk, such as high- or medium-refractive-index glass, plastic, or polymer, are contemplated herein. In such embodiments, the glass, plastic, or polymer material can be placed on the carrier plate 192 as a resin and then cured to harden it. In other embodiments, the faceted material can be index-matched with the LOE bulk material and used to manipulate an optical coating / optical sheet (e.g., from 3M) to achieve a desired spatial orientation (resulting in partial reflectivity).

[0095] In certain embodiments, facets having embedded magnetic and / or dielectric materials can be generated using a frame structure. For example, a certain amount of magnetic and / or dielectric material can be placed within a frame structure that is sized and dimensioned to correspond to the size and dimensions of a single facet, or to the size and dimensions of multiple adjacent facets (e.g., facets arranged side by side). The frame structure can then be filled with facet bulk material, such as optical glue, glass resin, plastic resin, or polymer resin. The bulk material can then be cured and hardened, and the facet structure having embedded magnetic and / or dielectric material can be removed from the frame. If multiple facets are generated, the facet structure can then be cut to extract individual facets, each having magnetic and / or dielectric material embedded within the facet. Optionally, a thin film coating and / or one or more optical sheets can be applied to the facets either before or after removal from the frame.

[0096] In other embodiments, a facet mold can be used to produce facets having embedded magnetic and / or dielectric materials. For example, a mold can be obtained that corresponds to the size and dimensions of a single facet, or to the size and dimensions of multiple adjacent facets (e.g., facets arranged side by side). The magnetic and / or dielectric material can be placed inside the mold, and then a facet bulk material (e.g., optical glue, glass resin, plastic resin, polymer resin) can be injected into the mold. The bulk material can then be cured and hardened, and the facet structure having embedded magnetic and / or dielectric material can be removed from the mold.

[0097] Facets having embedded magnetic and / or dielectric materials can be positioned within the frame 102 according to a suitable spatial configuration using, for example, a pick-and-place machine and / or jig, as described above. Alternatively, the positioning of such facets can be at least partially carried out by employing an apparatus having a device for applying controlled electric and / or controlled magnetic fields to the facets so that the electric and / or magnetic fields are controllably applied to the embedded material inside the facets. Figure 10 schematically illustrates a non-limiting exemplary embodiment of an apparatus 200 that can be used to position the facets of Figures 8A to 9F within the frame 102. The apparatus 200 includes a stage 202 supporting the frame 102 and a device 204 configured to generate controlled electric and / or magnetic fields 206a and / or magnetic fields 206b of controllable magnitude. In one configuration, device 204 controls the position and orientation of facets in three-dimensional space by generating controlled electric fields 206a and / or magnetic fields 206b to position facets within frame 102 according to the required spatial configuration. Device 204 typically includes a computerized control system, implemented as a computerized processor or controller coupled to, for example, a memory (e.g., memory), which controls device 204 to generate electric and / or magnetic fields. For example, the control system can actuate device 204 to generate electric and / or magnetic fields, and can change the magnitude / intensity of the generated electric and / or magnetic fields by, for example, changing the applied voltage over time and space. In another configuration, positioning facets within frame 102 according to the required spatial configuration can be assisted by a stage 202, which can be implemented as a movable stage that is movable along two or three movement axes and preferably also tiltable around two or three tilt axes. In such a configuration, the device 204 and the stage 202 may have separate control systems, and more preferably, a single control system may be used to control both the generation of the electric and / or magnetic field by the device 204 and the movement of the stage 202.For example, controlled electric and magnetic fields can be generated using various types of devices, including stepping motors, which are well known in the art.

[0098] Once the facets having embedded magnetic and / or dielectric materials are appropriately positioned within the frame, the facets are bonded to the frame in place, for example, using a low-refractive-index or medium-refractive-index optical adhesive that can be UV-cured. The frame can then be filled with a transparent optical material to form the bulk of the optical device. As discussed above, the transparent optical material may be a plastic, glass, or polymer resin that can be injected as a resin into the unoccupied areas of the frame, for example, via any suitable injection means. The injected resin can be solidified / hardened, preferably using curing, for example, via UV and / or thermal curing (e.g., via a UV lamp and / or heat lamp), to accelerate the hardening process and thereby form the bulk of the optical device.

[0099] In certain embodiments, the bulk material resin is a low-refractive-index optical adhesive or a medium-refractive-index optical adhesive. Embedding a high-refractive-index material within a low- or medium-refractive-index bulk LOE material to affect the partial reflective layer will be discussed in more detail below in the context of another embodiment with reference to Figures 13A and 13B.

[0100] In the embodiments described so far, the steps for fabricating an optical device generally involve arranging the fabricated facets (or other optical elements) within a frame structure in a predetermined position and orientation (spatial configuration), bonding the facets to the frame, and then forming a bulk material (e.g., low or high T gThis includes adding a material resin to the frame. On the other hand, other embodiments are contemplated herein in which the bulk portion of the optical device is preferably pre-constructed as a single piece and has defined openings configured to receive optical elements (e.g., facets), and the optical elements (e.g., facets) are placed in the openings and bonded to the bulk portion. Embodiments of such methods are described here with reference to Figures 11A to 11D. First, it should be noted that Figures 11A to 11D illustrate a particular exemplary configuration of an optical device implemented as a 2DLOE having two sets of facets, where the facets in a set are parallel to each other, but the two sets of facets have non-parallel orientations. On the other hand, as will be considered, the methods of Figures 11A to 11D can be used to fabricate various optical devices including 1DLOE, as well as optical devices having non-faceted optical elements instead of or in addition to faceted optical elements.

[0101] Referring here to Figure 11A, a solid block 300 of transparent material is obtained. The block 300 can be formed from any suitable optical material, including, for example, glass or plastic. In certain non-limiting embodiments, the block 300 is low T g Glass material or high T g It is formed from plastic / polymer materials.

[0102] Next, one or more portions / sections of the transparent material can be cut (removed) from the solid block 300 to produce a solid block 302 having one or more openings 304a, 304b in the locations where the material was removed from the block 300, as shown in Figure 11B. The portions / sections of the transparent material can be removed, for example, by laser etching, charged particle beam, or other suitable means.

[0103] In a preferred embodiment, the openings 304a, 304b are hollow openings extending between opposing faces (sides) of block 302 (only one face 308 is shown in the drawing). In a particular embodiment, the openings may be slits, slots, channels, or hollow grooves formed within block 302.

[0104] Each opening 304a, 304b has a spatial configuration that defines the internal surfaces 306a, 306b of block 302, the positions of the internal surfaces 306a, 306b within block 302, and the orientation of the internal surfaces 306a, 306b with respect to the external surface of block 302. In the illustrated embodiment, the spatial configuration of opening 304a is such that the internal surfaces 306a are parallel to each other, and the spatial configuration of opening 304b is such that the internal surfaces 306b are parallel to each other but not parallel to the internal surfaces 306a. Furthermore, the spatial configuration of opening 304b is such that the internal surface 306b is inclined obliquely with respect to the surface 308 of block 302. The spatial configuration of opening 304a is such that the internal surface 306a is either obliquely inclined with respect to the surface 308 or perpendicular to the surface 308.

[0105] As shown in Figure 11C, multiple facets 104a and 104b are also acquired. Each of the openings 304a and 304b is configured to receive one corresponding optical element (facets 104a and 104b). In particular, the openings 304a and 306b and facets 104a and 104b are configured in correspondence (i.e., in size and dimensions). As shown in Figure 11D, each of the openings 304 and 306 receives one corresponding facet 104a and 104b. In other words, each facet of facets 104a and 104b is inserted into one corresponding opening 304a and 304b. The inserted facets 104a and 104b are then joined within the opening, thereby joining the facets within the block 302. Each of the facets 104a and 104b has a spatial configuration, and as a result of the corresponding configurations of the openings 304a and 304b and the facets 104a and 104b, the facets 104a and 104b inherit the spatial configuration of their corresponding openings 304a and 304b. Note that when optically active areas of a facet (i.e., areas that will reflect or transmit image illumination) are joined to an opening, optical adhesive should be used for joining. On the other hand, when optically inactive areas of a facet (i.e., areas that do not deflect or transmit image illumination in a usable manner) are joined to an opening, non-optical adhesive can be used for joining.

[0106] Facets 104a and 104b can be manufactured, for example, using any of the techniques described above or any other suitable techniques. For example, in a particular embodiment, all of facets 104a and 104b are formed from a transparent plate, each coated with a partial reflective coating on one side (i.e., one-sided coated facets). In other embodiments, some of facets 104a and 104b are double-sided coated facets, and some of facets 104a and 104b are uncoated facets. In a particular embodiment, an alternating arrangement of double-sided coated facets and uncoated facets can be inserted into the openings such that each opening receiving a double-sided coated facet is adjacent to an opening receiving an uncoated facet, and each opening receiving an uncoated facet is adjacent to an opening receiving a double-sided coated facet. Such a configuration can achieve results similar to the alternating arrangement described in PCT Publication WO2020 / 212835.

[0107] In certain embodiments, a pair of surfaces, such as a cover plate, can be provided on opposing surfaces of block 302 (i.e., on surface 308 and its opposite surface). The pair of surfaces are preferably arranged so that they are parallel to each other, which may require adjustment of the pair of surfaces to address any non-parallelism between surface 308 and its opposite surface. The area or region between the parallel surfaces and block 302 can then be filled with a transparent filler material, such as optical glue, index matching liquid, or resin. The transparent filler material can then be left to solidify and harden, and / or the hardening process can be accelerated by curing, for example, using UV curing.

[0108] As described above, in the embodiments illustrated in Figures 11A to 11D, the fabricated optical device is a 2DLOE having two sets of facets, where the facets of the set are parallel to each other, but the two sets of facets have a non-parallel orientation. Thus, block 302 has a first set of parallel apertures 304a for receiving a first set of facets 104a, and a second set of parallel apertures 304b that are non-parallel to apertures 304a for receiving a second set of facets 104b. However, in principle, a solid block can have any number of apertures in any suitable spatial configuration for receiving any corresponding suitable number and type of optical elements, such as lenses, optical retarders, and polarizing beam splitters. In a simple embodiment, for example, in an embodiment in which the optical device includes a single optical element such as a reflective surface (e.g., a mirror), a lens, a retarder, or a polarizing beam splitter, a single aperture can be provided.

[0109] According to a particular embodiment, a block 302 (Figure 11B) having one or more openings 304a, 304b can be produced by compressing a bulk material resin in a mold having regions with ridges or bumps, such that the ridges or bumps in the mold form one or more openings 304a, 304b in the block as the resin hardens to form a block of bulk material. The facets can then be bonded to the openings, or the openings can then be filled with a suitable optical material such as a high refractive index optical glue to achieve partial reflectivity.

[0110] Referring here to Figures 12A to 12C, a method for fabricating a LOE according to another embodiment of the present disclosure is illustrated, in which a set of facets is inserted in appropriate locations between two similarly molded and dimensioned optical structures that are joined together. In particular, as illustrated in Figure 12A, the first optical structure 402a has a serrated configuration defining a set of surfaces 406a. Each surface 406a has a spatial configuration that defines the position of the surface 406a within the optical structure 402a and the orientation of the surface 406a with respect to an external surface of the optical structure 402a, for example, surface 404.

[0111] As illustrated in Figure 12B, surface 406a is configured to receive a corresponding set of facets 104 that can be bonded to surface 406a. When facets 104 are positioned on the corresponding surface 406a, facets 104 inherit the spatial configuration of surface 406a. As illustrated in Figure 12C, a second optical structure 402b, which is substantially similar to optical structure 402a, is then fitted with the first optical structure 402a, and the two optical structures 402a and 402b are bonded together to form a bonded structure 408 having embedded facets 104.

[0112] In the embodiments illustrated in Figures 12A to 12C, facet 104 can be manufactured, for example, using any of the techniques described above or any other suitable techniques. In one particularly preferred but non-limiting implantation, facet 104 may be low or high T as described above with reference to Figures 7A to 7C, for example. g It is constructed from a material having the following properties. The optical structures 402a and 402b can be manufactured in various ways, for example, using injection molding or casting, for example, low or high T g It can be constructed from a variety of optical materials, preferably from the same material used to construct the bulk portion of the facets.

[0113] In certain embodiments, facet 104 can be constructed from a high refractive index material, and optical structures 402a and 402b can be constructed from low or medium refractive index optical materials. In certain embodiments, facet 104 may be a single-sided coated facet, while in other embodiments, the first set of facets may be a double-sided coated facet, the second set of facets may be an uncoated facet, and the first and second sets of facets may be arranged in an alternating configuration, as previously considered.

[0114] Referring here to Figures 13A and 13B, a method for fabricating a LOE according to another embodiment of the present disclosure is illustrated. In this embodiment, the partial reflective layer (i.e., facets) of the LOE is mounted by a high refractive index optical adhesive embedded in a low refractive index transparent optical material such as low refractive index glass or low refractive index plastic. As shown in Figure 13A, a plurality of optical plates 502 are obtained, each having a pair of parallel main external surfaces 503a, 503b. As shown in Figure 13B, the optical plates 502 are bonded together to form a bonded laminate 500. The optical plates 502 are bonded together by providing one or more layers of optical adhesive 504 between adjacent plates 502. The optical plates 502 are formed from a low refractive index material such as low refractive index glass or low refractive index plastic, preferably having a refractive index of about 1.5. The optical adhesive is a high refractive index adhesive, preferably having a refractive index of about 1.7. The bonding process can be accelerated by thermal curing or UV curing of the optical adhesive 504. Furthermore, as shown in Figure 13B, the laminate 500 is cut along at least two parallel cutting planes 506 that are inclined with respect to the main surfaces 503a, 503b of the optical plate 502 to extract one or more LOEs, each extracted LOE having a pair of main outer surfaces (defined by the cutting planes 506) with embedded facets (formed from the adhesive layer 504). In addition to defining the main outer surfaces of the LOE, the cutting planes also define the oblique inclination angles of the facets (adhesive layer 504) embedded in the LOE. Specifically, the inclination angles of the cutting planes 506 with respect to the main surfaces 503a, 503b of the optical plate 502 in the laminate 500 define the inclination angles of the facets with respect to the main outer surfaces of the LOE.

[0115] It should be noted that high refractive index adhesives in low refractive index optical media have sufficient colorless reflectivity for s-polarized light at incident angles close to the Brewster angle. Therefore, for example, by adopting a tilt angle of approximately 57° for the cross-section 506, a LOE will be obtained in which the s-polarized image light propagating towards the facet, which collides with the facet at an angle of approximately 40° to 60°, is coupled out from the LOE, and the propagating image light, which collides with the facet at an angle of approximately 10° to 30°, is transmitted by the facet. This is specifically illustrated in Figure 14, which shows that when a high refractive index adhesive is used in a low refractive index optical medium, the reflectivity (Rs) of s-polarized light as a function of angle is low, but sufficient in the angular range of 40° to 60° (compared to the reflectivity Rp of p-polarized light in the same angular range), and at the same time, high transmittance (low Rs) of s-polarized light is achieved in the angular range of 10° to 30°.

[0116] The above method for mounting a partial reflective layer by embedding a high refractive index optical adhesive within a low refractive index transparent optical material can be extended to methods for generating 2DLOE, such as those described in PCT Publication WO2021 / 240513, PCT Publication WO2021 / 152602, PCT Publication WO2021 / 001841, and U.S. Patent No. 10,551,544.

[0117] In yet another embodiment, the partial reflective layer can be formed from a high refractive index optical adhesive, similar to the embodiments described above with reference to Figures 13A and 13B, but in contrast to the embodiments described above, the LOE bulk material can be formed from a low refractive index optical adhesive instead of an optical plate. In such embodiments, both low refractive index and high refractive index adhesives can be injected into the mold. For example, the low refractive index adhesive can be injected into a first set of molds, which in form may correspond to the optical plate 502 in Figures 13A and 13B, and the high refractive index adhesive can be injected into a second set of molds located between adjacent molds in the first set of molds. A movable stage (movable along two or three movement axes, and preferably tiltable around two or three tilt axes) can be used in the injection process to position the mold correctly relative to the adhesive injector. In certain embodiments, a UV source having one or more focused lasers can be used to cure the adhesive to provide higher resolution during the curing process.

[0118] In another embodiment, instead of injecting the high refractive index material (used to form facets) and the low refractive index material (used to form the LOE bulk) into a mold, the material can be deposited onto a carrier plate positioned on a movable stage, or deposited directly onto the movable stage itself, the movable stage being movable along two or three movement axes, and preferably also being tiltable around two or three tilt axes. In such embodiments, the fabrication process can employ a cycle of material placement (e.g., low refractive index bulk and / or high refractive index facet deposition), curing (e.g., UV / thermal curing), cleaning or washing of residual material (e.g., incompressible portions of the high or low refractive index material), and drying. After each cycle, the stage can be moved (e.g., via a control system) to orient the stage (and thus the LOE under construction) to the appropriate orientation so that the facets inherit the appropriate spatial configuration. Similar to the embodiments described above, the curing process can employ a UV source having one or more focused lasers for curing the low refractive index and high refractive index materials to provide higher resolution during the curing process. In further embodiments, LOEs can be fabricated by constructing the LOE bulk through the deposition of optical bulk material and the deposition of optical material as a resin in thin layers within the LOE bulk material. The deposited thin layers of optical material within the LOE bulk material mimic the optical behavior of thin-film multilayer partial reflection coatings in conventional LOE fabrication. The optical materials have different refractive indices and are deposited sequentially in thin layers on or within the bulk material (preferably on a submicrometer scale, e.g., less than 10 nanometers, more preferably less than 5 nanometers, but can reach thicknesses of 1-2 microns or more) to achieve partial reflection functionality. In a non-limiting example, the LOE bulk is partially constructed by depositing multiple layers of optical bulk material (having a certain refractive index, e.g., 1.5) on or directly on a carrier plate placed on a movable stage. Then, a first thin layer of a first optical material (e.g., optical glue) having a first refractive index (e.g., 1.34) is deposited on the partially constructed bulk material.Next, a second thin layer of a second optical material (e.g., optical glue) having a second refractive index (e.g., 1.6) is deposited on the first thin layer. This can be continued as needed, or according to the LOE optical design and / or specific facet optical requirements. Low / high layers (1.34 / 1.6) can be repeated to satisfy the optical requirements, or, for example, other refractive indices can also be repeated, such as a third layer of optical glue having a third refractive index (e.g., 1.5) deposited on the second thin layer, and a fourth layer of optical glue having a fourth refractive index (e.g., 1.7) deposited on the third thin layer. After the deposition of each thin layer, the optical material can be cured and then cleaned or washed (as discussed above). Furthermore, during the deposition of each thin layer, the movable stage can be controlledly moved to orient the stage (and thus the LOE under construction) to the appropriate orientation so that the thin layers (together forming facets) inherit the appropriate spatial configuration. This layering of multiple thin and bulk materials can be repeated facet by facet as needed until the LOE is fully constructed.

[0119] Throughout this document, there is reference to the coating and / or injection of optical materials, including transparent optical materials in the form of optical adhesives and resins. Such coating and / or injection can be achieved by the use of a suitable applicator and / or injector (syringe) that provides electronic and / or electromechanical control of the deposition of the optical material, including one or more of the thickness of the deposited optical material and the location of deposition. One preferred arrangement having a suitable applicator / injector that may be used in some of the fabrication processes disclosed herein is the FlashForge Guider 33D printer, commercially available from FlashForge USA in Los Angeles, California.

[0120] The descriptions of the various embodiments of this disclosure are presented for illustrative purposes only and are not intended to be exhaustive or limitful to the embodiments disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the embodiments described. The terms used herein have been selected to best describe the principles of the embodiments, their practical applications or technical improvements to the technologies available on the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0121] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly indicates otherwise.

[0122] The term “exemplary” is used herein to mean “serving as an example, illustration, or illustration.” Any embodiment described as “exemplary” should not necessarily be construed as being preferable or advantageous to other embodiments, and / or preclude the incorporation of features from other embodiments.

[0123] For clarity, it should be understood that certain features of the Disclosure described in the context of separate embodiments may be provided in combination in a single embodiment. Conversely, for brevity, various features of the Disclosure described in the context of a single embodiment may be provided separately, in any preferred partial combination, or as suitable for any other described embodiment of the Disclosure. Certain features described in the context of various embodiments should not be considered essential features of those embodiments unless the embodiments would not function without those elements.

[0124] To the extent that the attached claims are drafted without multiple dependencies, this is done solely to comply with the formal requirements of jurisdictions that do not permit such multiple dependencies. Note that all possible combinations of features that would be implied by making the claims multiple dependencies are explicitly assumed and should be considered part of this disclosure.

[0125] While this disclosure has been described in relation to its particular embodiments, it is obvious that many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, it is intended to encompass all such alternatives, modifications, and variations that fall within the spirit and broad scope of the appended claims.

Claims

1. A method for fabricating optical devices, Obtaining at least one optical element, To obtain a frame, The at least one optical element is arranged within the frame according to a spatial configuration that defines the position of the at least one optical element within the frame and the orientation of the at least one optical element relative to the frame, The spatial configuration is fixed by joining the at least one optical element to the frame, A method comprising filling the region of the frame not occupied by the at least one optical element with a transparent optical material.

2. The method according to claim 1, further comprising arranging the frame between a pair of parallel surfaces such that the at least one optical element is located between the parallel surfaces, before filling the region of the frame with the transparent optical material.

3. The method according to claim 1, further comprising curing the transparent optical material.

4. The method according to claim 1, wherein the at least one optical element is constructed from the same material as the transparent optical material.

5. The method according to claim 1, wherein the at least one optical element is constructed from a glass material having a low glass transition temperature, or from a plastic or polymer material having a high glass transition temperature.

6. The method according to claim 1, wherein arranging the at least one optical element within the frame includes deploying a device that arranges each of the at least one optical element according to the spatial configuration.

7. The method according to claim 1, wherein the at least one optical element has a material embedded inside the at least one optical element that is sensitive to at least one of an electric field or a magnetic field.

8. The method according to claim 7, wherein the arrangement of the at least one optical element within the frame is at least partially carried out by applying at least one of an electric field or a magnetic field to the embedded material inside the at least one optical element.

9. The method according to claim 7, wherein the embedded material includes at least one of a ferromagnetic material or a dielectric material.

10. The method according to claim 1, wherein the at least one optical element includes a planar partial reflective surface.

11. The method according to claim 1, wherein the at least one optical element includes a lens.

12. The method according to claim 1, wherein the at least one optical element includes a polarizing beam splitter.

13. The method according to claim 1, wherein the at least one optical element includes an optical retarder.

14. The method according to claim 1, wherein the at least one optical element includes a reflective surface.

15. The method according to claim 1, wherein the at least one optical element includes a plurality of optical elements.

16. The method according to claim 15, wherein the plurality of optical elements include a first plurality of planar partial reflective surfaces.

17. The method according to claim 16, wherein the orientation defined by the spatial configuration is such that the first plurality of partial reflective surfaces are obliquely inclined with respect to a pair of parallel surfaces between which the frame lies.

18. The method according to claim 16, wherein the orientation defined by the spatial configuration is such that the first plurality of partial reflective surfaces are perpendicular to a pair of parallel surfaces between which the frame lies.

19. The method according to claim 16, wherein the orientation defined by the spatial configuration is such that the first plurality of partial reflective surfaces are parallel to each other.

20. To obtain a second set of planar partial reflective surfaces, The method according to claim 19, further comprising arranging the second plurality of partial reflective surfaces within the frame according to a second spatial configuration that defines the positions of the second plurality of partial reflective surfaces within the frame and the orientation of the second plurality of partial reflective surfaces with respect to the frame, wherein the orientation defined by the second spatial configuration is such that the second plurality of partial reflective surfaces are parallel to each other and non-parallel to the first plurality of partial reflective surfaces.

21. The at least one optical element includes a plurality of planar partial reflective surfaces, and obtaining the at least one optical element is To obtain a production plate formed from glass having a low glass transition temperature or from a plastic or polymer material having a high glass transition temperature, The aforementioned generating plate is coated with a partial reflection coating, The method according to claim 1, comprising slicing the coated generating plate to generate a plurality of coated plates, wherein each coated plate is a planar partially reflective surface.

22. The at least one optical element includes a plurality of planar partial reflective surfaces, and obtaining the at least one optical element is Obtaining multiple production plates, each production plate being formed from glass having a low glass transition temperature or from a plastic or polymer material having a high glass transition temperature, Each of the aforementioned generating plates is coated with a partial reflection coating, The coated generating plates are laminated onto a laminate, and the coated generating plates are temporarily joined together with a temporary adhesive. The method according to claim 1, comprising slicing the laminate and removing the temporary adhesive to produce a plurality of coated plates, wherein each coated plate is a planar partially reflective surface.

23. Obtaining the aforementioned at least one optical element is Obtaining a certain amount of material that is sensitive to at least one of an electric field or a magnetic field, The method according to claim 1, comprising embedding the amount of the material in an optical material in order to form the at least one optical element.

24. A method for fabricating optical devices, Obtaining at least one optical element, Obtaining a block of transparent material, wherein the block of transparent material has at least one opening, the at least one opening and the at least one optical element are configured in correspondence, and each of the at least one opening is an internal surface of the block, and the internal surface of the block is defined by a spatial configuration that defines the position of the internal surface within the block and the orientation of the internal surface with respect to the external surface of the block. Inserting each of the at least one optical elements into a corresponding opening among the at least one opening, A method comprising joining each of the at least one optical elements into the corresponding opening.

25. The method according to claim 24, further comprising: arranging the block between a pair of parallel surfaces such that the at least one optical element is located between the plates; and filling the area between the parallel surfaces and the block with a transparent filler material.

26. The method according to claim 25, wherein the transparent filling material comprises at least one of an optical adhesive or an index matching liquid.

27. The method according to claim 25, wherein the transparent material is a glass having a low glass transition temperature, or a plastic or polymer material having a high glass transition temperature.

28. The method according to claim 24, wherein the at least one optical element is constructed from glass having a low glass transition temperature, or from a plastic or polymer material having a high glass transition temperature.

29. The method according to claim 24, wherein the at least one optical element includes a planar partial reflective surface.

30. The method according to claim 24, wherein the at least one optical element includes a lens.

31. The method according to claim 24, wherein the at least one optical element includes a polarizing beam splitter.

32. The method according to claim 24, wherein the at least one optical element includes an optical retarder.

33. The method according to claim 24, wherein the at least one optical element includes a plurality of planar partial reflective surfaces.

34. The method according to claim 24, wherein the at least one opening includes a plurality of openings defining a plurality of first internal surfaces, and the orientation of the first internal surfaces defined by the spatial configuration is such that the first internal surfaces are parallel to each other.

35. The method comprises at least one optical element including a first plurality of planar partial reflective surfaces, the block of the transparent material having a second plurality of openings, each of the second plurality of openings being a second internal surface of the block having a second spatial configuration that defines the position of the second internal surface within the block and the orientation of the second internal surface with respect to the outer surface of the block, wherein the orientation of the second internal surface defined by the second spatial configuration is such that the second internal surfaces are parallel to each other and non-parallel to the first internal surface, and the method is To obtain a second plurality of planar partial reflections, wherein the second plurality of apertures and the second plurality of partial reflection surfaces are configured in correspondence, Inserting each of the second plurality of partial reflective surfaces into a corresponding one of the second plurality of elongated openings, The method according to claim 34, further comprising joining the partial reflective surfaces of the second plurality of partial reflective surfaces to the openings of the second plurality of openings.

36. The method according to claim 24, wherein obtaining the block of transparent material comprises obtaining a solid block of transparent material and removing at least a portion of the solid block to produce the at least one opening.

Images