Optical device and method for manufacturing an optical device

Abstract

The present disclosure relates to an optical device and a method for manufacturing an optical device. Wherein the optical device comprises: a first waveguide comprising a first surface; the first waveguide comprises a first surface, the second waveguide comprises a second surface, the first waveguide is in a fixed position relative to the second waveguide, the first surface at least partially faces the second surface, the first surface comprises a first positioning element, and the first positioning element is a nanoimprint lithography structure; the first surface comprises a first positioning element, and the second surface comprises a second positioning element which is a nanoimprint lithography structure; the optical device further comprises an adhesive arranged for attaching the first surface to the second surface, where the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises a hydrophobic region, the hydrophobic region is adapted to repel the adhesive by having a higher contact angle with the adhesive than the surrounding region.

Description

[0001] This application is a divisional application of the application with national application number 202180026533.5, international application date April 7, 2021, national entry date September 30, 2022, and invention name “Optical Device”. Technical Field

[0002] The present disclosure relates to optical devices including waveguides. For example, such optical devices can be used in near-eye displays. Background Art

[0003] Optical devices including multiple stacked waveguides are desirable in various scenarios. For example, each of the multiple stacked waveguides can be optimized to guide light having a correspondingly different frequency, so that the optical device as a whole is capable of guiding light over a wide frequency range.

[0004] For example, in a virtual reality headset, an optical device including one or more waveguides is provided in front of one or both eyes of a user. A light projector transmits light toward the waveguides. Light may be coupled into each waveguide by an input diffraction grating. The light then propagates within each waveguide by total internal reflection, and an output diffraction grating couples the light out of each waveguide and toward the viewer.

[0005] Additionally, the viewer may be able to see light from their external environment, transmitted through the waveguide, and projected light from the projector. This may provide an augmented reality experience.

[0006] One challenge in the field of virtual or augmented reality is to provide a full-color display using projected light. Aberrations and effects introduced by optics mean that this can be difficult to achieve in practice. By stacking multiple waveguides optimized for different frequencies, each waveguide can provide a color component of a full-color display while minimizing any aberrations or undesired optical effects.

[0007] The application of optical devices with stacked waveguides requires precise positioning of the waveguides in the stack. For example, the waveguides are preferably kept as close together as possible to reduce the apparent volume of the optical device. However, the distance between the waveguides must be kept large enough to eliminate evanescent wave coupling and minimize crosstalk or energy losses. Similarly, the lateral positioning of the waveguides must be precisely controlled, for example to align the optically functional areas of different waveguides.

[0008] Stacked waveguides are typically attached to each other using an adhesive such as glue. However, a problem with such adhesives is that they can flow. In the case of flowing adhesives, it is difficult to precisely control the distance between waveguides or the lateral positioning of the waveguides because either or both of these properties may change as the adhesive cures.

[0009] It would therefore be desirable to provide an optical device comprising a plurality of waveguides in which the relative positioning of the waveguides is precisely controlled.

[0010] In addition, each waveguide has at least one optically functional area on the surface. For example, the at least one optically functional area may be an area where light enters or leaves the waveguide. The flowing adhesive may partially flow along the surface into the optically functional area and prevent the waveguide from functioning or reduce the effectiveness of the waveguide.

[0011] It would therefore be desirable to provide an optical device comprising a plurality of waveguides in which the position of the adhesive between the waveguides is precisely controlled. Summary of the invention

[0012] According to a first aspect of the present disclosure, an optical device is provided, comprising: a first waveguide, the first waveguide comprising a first surface; and a second waveguide, the second waveguide comprising a second surface, wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, and the first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography (NIL) structure.

[0013] Providing a NIL positioning element has the effect of more conveniently and / or more accurately defining the relative position of the first waveguide and the second waveguide.

[0014] Optionally, the first positioning element is arranged to control a position of the second surface relative to the first surface.

[0015] By specifically using the NIL positioning element to control the relative position of the two surfaces, the positioning element can be used as a precise physical constraint on the relative position of the two surfaces.

[0016] Optionally, the first positioning element is arranged to control a spacing between the first surface and the second surface.

[0017] Using a NIL positioning element to control the spacing between the two waveguides means that it is no longer necessary to use more complex positioning techniques based on optical feedback such as tracking of images or fiducials through the waveguides. Instead, the two surfaces can simply be placed in physical contact and the NIL positioning element can correctly control the desired spacing between the waveguides.

[0018] Optionally, the second surface comprises a second positioning element, and the second positioning element is a nanoimprint lithography (NIL) structure.

[0019] Providing a second positioning element on the surface opposite to the first surface reinforces the advantages of the first positioning element on the first surface. In addition, by extending the positioning function across both surfaces, the density of NIL modification on each surface can be reduced.

[0020] Optionally, the second positioning element is adapted to engage with the first positioning element.

[0021] Providing locating elements on opposing surfaces of the waveguide and adapting the locating elements to engage each other means that locating elements on one surface do not have to contact the opposing surface. This therefore reduces the likelihood of damaging the surface of the waveguide during assembly of the optical device.

[0022] Optionally, the optical device further comprises an adhesive arranged to attach the first surface to the second surface.

[0023] Attaching the waveguides together ensures that precise relative positioning is maintained.

[0024] Optionally, the first positioning element is arranged to control the position of the adhesive.

[0025] Providing positioning elements for controlling the position of the adhesive enables precise control of where the adhesive is located, thereby ensuring that the adhesive is adequately disposed in areas intended for bonding the two surfaces and that the adhesive is absent in areas not intended for bonding the two surfaces.

[0026] Optionally, the first positioning element comprises: an affinic region adapted to attract the adhesive; or a phobic region adapted to repel the adhesive.

[0027] Modifying the attractiveness or repulsiveness of the first surface means that the positioning element can control the position of the adhesive without using solid protrusions to block and / or contain the adhesive. For example, this controls the position of the adhesive without reducing the volume of adhesive that can be contained between two waveguides and enables the adhesive to be removed without damaging the positioning element.

[0028] Optionally, the first surface or the second surface includes an optical function area, the first positioning element includes a barrier portion arranged to surround the optical function area, and the adhesive is arranged on the first surface outside the barrier portion.

[0029] Such an arrangement of the barrier portion has the advantage of preventing the adhesive from flowing into the optically functional area and thus increasing the likelihood that the optical device will function correctly after assembly.

[0030] Optionally, the adhesive is opaque.

[0031] The use of an opaque adhesive enables the adhesive to simultaneously reduce interference from light sources not intended as input to the waveguide.

[0032] Optionally, the adhesive is adapted to control a spacing between the first surface and the second surface.

[0033] Using an adhesive adapted to control the spacing between the waveguides means that the positioning elements can simultaneously and synergistically prevent the adhesive from spreading to areas where it should not spread, and improve the precision of the spacing between the waveguides.

[0034] Optionally, the adhesive comprises microspheres or beads.

[0035] The microspheres and beads provide a solid or elastic component to the adhesive, which sets the minimum thickness of the adhesive. By controlling the size of the microspheres or beads, the spacing between the waveguides can also be controlled.

[0036] According to a second aspect of the present disclosure, there is provided a method for manufacturing an optical device, the optical device comprising a first waveguide and a second waveguide, wherein the first waveguide is in a fixed position relative to the second waveguide, the method comprising: performing nanoimprint lithography on a first surface of the first waveguide to produce positioning elements on the first surface; and arranging the first waveguide in a fixed position relative to the second waveguide using the positioning elements, wherein the first surface at least partially faces the second surface.

[0037] Performing nanoimprint lithography to create the NIL positioning element has the effect of more conveniently and / or more accurately defining the relative position of the first waveguide and the second waveguide.

[0038] According to one aspect of the present disclosure, an optical device is provided, comprising: a first waveguide comprising a first surface; and a second waveguide comprising a second surface, wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, the first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography structure; and the second surface comprises a second positioning element, wherein the second positioning element is a nanoimprint lithography structure; the optical device also comprises an adhesive, the adhesive is arranged to attach the first surface to the second surface, wherein the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises a hydrophobic region, the hydrophobic region is adapted to repel the adhesive by having a higher contact angle with the adhesive than the surrounding area.

[0039] According to one aspect of the present disclosure, a method for manufacturing an optical device is provided, the optical device comprising a first waveguide and a second waveguide, wherein the first waveguide is in a fixed position relative to the second waveguide, the method comprising: performing nanoimprint lithography on a first surface of the first waveguide to produce a first positioning element on the first surface; performing nanoimprint lithography on a second surface of the second waveguide to produce a second positioning element on the second surface; using the first positioning element and the second positioning element to arrange the first waveguide at a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface of the second waveguide; and providing an adhesive for attaching the first surface to the second surface, wherein the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises a hydrophobic region adapted to repel the adhesive by having a higher contact angle with the adhesive than a surrounding area.

[0040] According to one aspect of the present disclosure, an optical device is provided, comprising: a first waveguide comprising a first surface; and a second waveguide comprising a second surface, wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, the first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography structure; and the second surface comprises a second positioning element, wherein the second positioning element is a nanoimprint lithography structure; the optical device also comprises an adhesive, the adhesive is arranged to attach the first surface to the second surface, wherein the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises an affinity region, the affinity region is adapted to attract the adhesive by having a lower contact angle with the adhesive than the surrounding area.

[0041] According to one aspect of the present disclosure, a method for manufacturing an optical device is provided, the optical device comprising a first waveguide and a second waveguide, wherein the first waveguide is in a fixed position relative to the second waveguide, the method comprising: performing nanoimprint lithography on a first surface of the first waveguide to produce a first positioning element on the first surface; performing nanoimprint lithography on a second surface of the second waveguide to produce a second positioning element on the second surface; arranging the first waveguide at a fixed position relative to the second waveguide using the first positioning element and the second positioning element, wherein the first surface at least partially faces the second surface of the second waveguide; and providing an adhesive for attaching the first surface to the second surface, wherein the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises an affinity region adapted to attract the adhesive by having a lower contact angle with the adhesive than a surrounding area. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a schematic diagram of an optical device manufactured according to known techniques;

[0043] Figure 2A is a schematic diagram of an optical device according to an embodiment;

[0044] Figure 2B is a schematic diagram of an optical device in which a first positioning element is adapted to engage with a second positioning element;

[0045] Figure 3A and Figure 3B It is a schematic diagram of the hydrophobic and hydrophilic regions on the surface;

[0046] Figure 4A and Figure 4B is a schematic diagram of positioning elements on the waveguide surface;

[0047] Figure 5 is a flowchart schematically illustrating a method of manufacturing an optical device according to an embodiment.

[0048] Figure 6 is a stereoscopic diagram of a user wearing a portion of an augmented reality device in an embodiment of the present invention. DETAILED DESCRIPTION

[0049] Figure 1 Schematically shown is a cross section of an optical device 1 comprising a first waveguide 11 and a second waveguide 12. A first surface 13 of the first waveguide 11 is arranged to face a second surface 14 of the second waveguide 12.

[0050] With such an arrangement, the first optical functional region 15 of the first waveguide 11 and the second optical functional region 16 of the second waveguide 12 can be arranged on a common optical axis. For example, the first optical functional region 15 and the second optical functional region 16 can be output gratings arranged to diffract light onto the common optical axis for providing combined light output from the optical device. Alternatively, the first optical functional region 15 and the second optical functional region 16 can be input gratings arranged to diffract different optical frequency ranges from incident light into the respective waveguides 11, 12.

[0051] The first waveguide 11 and the second waveguide 12 are formed by using one or more regions of adhesive 17 (eg Figure 1 The adhesive 17 has the effect of fixing the relative position of the first waveguide 11 with respect to the second waveguide 12.

[0052] However, by comparison Figure 1 As can be seen from the different areas of adhesive 17 in FIG. 1 , this approach cannot reliably provide a constant spacing between the first waveguide 11 and the second waveguide 12. In this example, the two waveguides 11, 12 are spaced closer together on the right side of the figure than on the left side.

[0053] Furthermore, in this example, there is nothing to prevent the adhesive 17 from flowing into the optically functional area 15 on the first surface 13 during manufacturing before the adhesive is cured.

[0054] In accordance with the present invention, nanoimprint lithography (NIL) is used to address either or both of these issues.

[0055] Nanoimprint lithography involves deforming an imprint resist using a mold and curing the resist in the final shape. For example, the resist can be a thermoplastic material that is subjected to heat during molding, or a UV-curable material that is subjected to UV light while it is in the mold. When the mold is removed, the resist has the desired shape defined by the mold.

[0056] As an example, the resist may include a polymer such as polypropylene. As another example, the resist may include a transparent resin, specifically, a high refractive index transparent resin. The mold may include a material similar to the resist. Alternatively, a harder material may be used to make the mold. For example, electroplated nickel may be used to make the mold.

[0057] Nanoimprint lithography can be used to modify an existing surface by first depositing the resist as a film on the surface. For example, the resist can be deposited using spin coating. After deposition, the resist is deformed as described above. Alternatively, the resist can be molded before attaching the resist to the existing surface.

[0058] With this technique, customized surface structures with micrometer- or nanometer-scale dimensions can be added to the surface.

[0059] The theory of nanoimprint lithography is discussed, for example, in Ariadna FernandezEstevez's 2016 doctoral thesis "Functional surfaces by means of nanoimprint lithography techniques" at the Autonomous University of Barcelona.

[0060] Figure 2A is a schematic cross-sectional view of an optical device according to an embodiment. Unless otherwise described below, Figure 2A The optical device can be used with Figure 1 The optical device is the same.

[0061] like Figure 2A As shown, the optical device 2 includes a first waveguide 21 and a second waveguide 22, and a first surface 23 of the first waveguide is arranged to face a second surface 24 of the second waveguide.

[0062] In this embodiment, the two waveguides 21, 22 have similar shapes, and the first surface 23 is completely aligned to face the second surface 24. However, this is not necessary for embodiments of the present invention, and in other embodiments, the first surface 23 may have different shapes than the second surface 24 and / or may only partially face the second surface 24.

[0063] In this embodiment, each waveguide 21, 22 has two optical functional regions 25, 26. The first optical functional region on each waveguide is arranged along the input optical axis A. i The second optical function area on each waveguide is arranged along the output optical axis A. o For example, the optical device can be arranged to receive a i The incident light in the field of view and the output is around the output optical axis A o In other embodiments, each waveguide may have one or more optically functional regions arranged in any manner.

[0064] In this embodiment, the first surface 23 comprises three positioning elements 27 , 28 , each of which is a nanoimprint lithography (NIL) structure. Each of the positioning elements 27 , 28 is arranged to control the position of the second surface 24 relative to the first surface 23 .

[0065] The first positioning element 27 is arranged to control the spacing between the first surface 23 and the second surface 24. For example, the first positioning element 27 may be a block or a columnar protrusion from the first surface 23.

[0066] The second and third positioning elements 28 are arranged to control both the spacing between the first surface 23 and the second surface 24 and the relative position of the waveguide in the second direction (labeled as the x direction). In the embodiment shown in FIG. 2 , this is achieved by adapting the second and third positioning elements 28 to cooperate with the corners of the second waveguide 22.

[0067] More generally, one or more positioning elements may be arranged to control the position of the second surface relative to the first surface in three dimensions. For example, a plurality of positioning elements including different height protrusions from the first surface 23 may be used to define an inclined space between the first surface 23 and the second surface 24.

[0068] In addition, the second surface 24 may also include one or more positioning elements as nanoimprint lithography (NIL) structures. For example, the first positioning element 27 may protrude from the second surface 24 instead of protruding from the first surface 23 .

[0069] For example, Figure 2BAs shown, the positioning element 272 of the second surface 24 can be adapted to engage with the positioning element 271 of the first surface 23. For example, two positioning elements each including a protrusion can be adapted to engage end to end. This has the advantage that the positioning element of one surface does not have to contact the other surface, and reduces the risk of damaging the surface of the waveguide when constructing the optical device.

[0070] An adhesive may be arranged to attach the first surface 23 to the second surface 24. For example, the adhesive may be arranged on one or more of the positioning elements.

[0071] You can Figure 1 The adhesive is simply placed as shown and allowed to cure. However, it is advantageous to provide a positioning element on the first surface or the second surface that is adapted to control the position of the adhesive, for example to prevent the adhesive from flowing into the optical function area. This positioning element can be provided in addition to the positioning element described above for controlling the position of the second surface relative to the first surface, or in place of the positioning element described above for controlling the position of the second surface relative to the first surface.

[0072] like Figure 3A and Figure 3B As schematically shown in , nanoimprint lithography can additionally be used to create hydrophobic structures that repel the binder and hydrophilic structures that attract the binder.

[0073] For a smooth surface, whether a liquid or gel (hereinafter simply referred to as a "liquid") is attracted to the surface (philic surface) or repelled by the surface (phobic surface) depends on the surface bond. More specifically, if the total surface energy of the liquid (including the energy at the solid-liquid interface and the energy at the liquid-gas interface) is reduced by spreading on the surface, the liquid will "wet" the surface, i.e., spread on the surface. As the liquid spreads, the contact angle between the surface and the liquid changes, and eventually reaches an equilibrium where further spreading does not reduce the surface energy.

[0074] In this specification, "affinity" and "phobic" are defined relative to each other. The degree to which an adhesive is attracted to a surface depends on the contact angle formed when the adhesive rests on the surface.

[0075] At the boundary between a surface with a higher contact angle (relatively hydrophobic surface) and a surface with a lower contact angle (relatively hydrophilic surface), the adhesive is preferentially attracted to the hydrophilic surface with a lower surface energy and is effectively repelled from the hydrophobic surface with a higher surface energy. Thus, the boundary acts as a barrier to prevent the adhesive from moving from the hydrophilic surface to the hydrophobic surface.

[0076] Additionally, the higher the contact angle, the lower the contact surface area between the surface and the adhesive, and the less firmly the adhesive is bonded to the surface, making it easier for the adhesive to slide (flow) over the surface or to separate from the surface.

[0077] As described in detail in the previously mentioned 2016 paper "Functional surfaces by means of nanoimprint lithography techniques" by Ariadna Fernandez Estevez of the Autonomous University of Barcelona, ​​a general surface roughness or designed surface structure can have the effect of increasing the contact angle and / or reducing the contact surface area, i.e., increasing the relative "phobicity" of the surface. Nanoimprint lithography can be used to produce such a liquid-repellent surface, for example, by producing a pattern of nanoscale protrusions. By designing the pattern of protrusions to be close enough that surface tension prevents liquid from flowing into the gaps between the protrusions, and designing the protrusions to be narrow so that the proportional contact area with the protrusions is low, a "superphobic" surface can be produced in which there are air gaps between the surface and the liquid and the contact area between the surface and the liquid is reduced.

[0078] Figure 3A A drop of adhesive 31 is shown resting on a hydrophobic area 32. In this case, the pattern of protrusions has a protrusion pitch equal to the protrusion width. Thus, a drop 31 resting on three protrusions has a proportional contact area of ​​60% compared to a smooth surface of the same material.

[0079] on the other hand, Figure 3B A drop of adhesive 31 is shown resting on a hydrophilic region 33 between two hydrophobic regions 32. In this case, the drop 31 rests on a smooth surface with a 100% proportional contact area.

[0080] Therefore, with Figure 3A Compared with Figure 3B The middle droplet 31 is in a lower energy state (a more attractive state). Figure 3B The status shown changes to Figure 3A The state shown requires an increase in the surface energy of the adhesive 31, and this energy change corresponds to the repulsive effect of the hydrophobic region and the attractive effect of the hydrophilic region.

[0081] The above principles apply to any liquid or gel in contact with any surface. The equilibrium contact angle between a liquid or gel and a smooth surface depends on the chemical nature of the materials involved, and the scale of structural modifications required to increase repellency depends on this equilibrium contact angle.

[0082] By modifying the relative attractiveness or repulsion of the surface to the adhesive, rather than using e.g. Figure 2AThe structure shown physically blocks movement of the adhesive, providing the additional advantage that the adhesive can be removed (e.g. chemically dissolved) without having to destroy or remove the physical barrier, and therefore this form of positioning element does not hinder deconstruction of the optical device to retrieve individual waveguides (e.g. as part of a recovery method).

[0083] Figure 4A is a schematic diagram of a surface of a waveguide 4 including a first optical function region 41, a second optical function region 42 and a positioning element 43. As previously described with respect to Fig. 2, the waveguide 4 may be arranged to face the second waveguide.

[0084] In this case, the first optically functional region 41 is an input grating and the second optically functional region 42 is an output grating. More generally, the surface may have one or more optically functional regions of any type.

[0085] Figure 4B An enlarged view of a portion of the positioning element 43 is shown. In more detail, the positioning element 43 includes a first hydrophobic region 431 , a first hydrophilic region 432 , a second hydrophobic region 433 , and a second hydrophilic region 434 .

[0086] The affinity region and the repellency region of the positioning element 43 are provided as a series of concentric portions, and the series of concentric portions are arranged to surround the first optical function region 41 and the second optical function region 42 .

[0087] The innermost part, i.e., the first hydrophobic region 431, is arranged as a barrier portion surrounding the optical functional region. With this arrangement, the barrier portion divides the surface of the waveguide into a second portion and a first portion including the optical functional regions 41, 42. The adhesive placed in the second portion outside the barrier portion is prevented from moving into the first portion by the barrier portion, and is therefore prevented from moving into the optical functional regions 41, 42.

[0088] Surrounding the first hydrophobic region 431 is a first hydrophobic region 432, and surrounding the first hydrophobic region 432 is a second hydrophobic region 433. This arrangement is similar to that described above. Figure 3B . For example Figure 3B As described, the adhesive placed on the first affinity region 432 is prevented from moving out of the first affinity region 432, as this would require moving to the first hydrophobic region 431 or the second hydrophobic region 433. Thus, the arrangement of the first hydrophobic region 431, the first hydrophobic region 432, and the second hydrophobic region 433 defines a first region of the waveguide surface in which the adhesive may be confined.

[0089] The waveguide shown in Figure 4 also includes a second affinity region 434, which extends to the edge of the waveguide 4. The arrangement of the second repellent region 433 and the second affinity region 434 defines a second region of the waveguide surface in which an adhesive can be incorporated. The second region of the waveguide surface can be used to confine an adhesive different from the adhesive of the first region.

[0090] For example, a second region corresponding to the second affinity region 434 may be used to confine an opaque adhesive and thereby prevent unwanted light from entering an optical device including the waveguide 4 between the respective ends of the pair of waveguides.

[0091] On the other hand, as a supplement or alternative to the positioning element 27 previously shown in Figure 2, the first area corresponding to the first affinity region 432 can be used to limit the adhesive adapted to control the interval between the waveguides (e.g., the interval between the first surface 23 and the second surface 24). In one embodiment, the adhesive can include microspheres or beads. In such an embodiment, the fluid component of the adhesive can flow to reduce the interval between the first surface and the second surface, but the microspheres or beads define the minimum interval that can be occupied by the adhesive. Alternatively, by using one or more affinity regions and / or hydrophobic regions to limit the adhesive of a known volume, or by using one or more NIL protrusions as a direct barrier rather than a hydrophobic barrier, the interval between the first surface and the second surface can be controlled.

[0092] In the example shown in Figure 4, the two optically functional regions 41, 42 are located on the same surface of the waveguide 4 as the positioning element 43. However, the above-described techniques can generally be used to keep the adhesive out of the light path associated with any optically functional region, which may be on the same surface as the positioning element 43, on the opposite surface of the waveguide 4, or on a different waveguide of an optical device that includes the waveguide 4.

[0093] The specific example above includes two hydrophilic regions and two hydrophobic regions. However, in embodiments of the invention having positioning elements arranged to control the position of the adhesive, the positioning elements may have any number of hydrophilic or hydrophobic regions.

[0094] For example, another embodiment includes the hydrophobic barrier portion being arranged to form a loop in which the adhesive can be placed. Thus, the hydrophobic portion need not surround the optically functional area.

[0095] Where the affinity region is provided in isolation, it will be understood that the affinity region is smoother than the surrounding surface, or is a region having a different surface material or a coating having a lower contact angle than the surrounding surface.

[0096] You can Figure 5The optical device according to the present invention is manufactured as shown, for example Figure 2A The optical device shown in FIG. 4 , or the optical device having the waveguide 4 as shown in FIG. 4 .

[0097] First, at step S510, each individual waveguide 21, 22 is produced using known techniques.

[0098] At step S520, nanoimprint lithography (NIL) is performed on one or more surfaces 23, 24 of the waveguides 21, 22, 4 using the above-described techniques to produce one or more positioning elements 27, 28, 43. This step includes performing NIL on at least a first surface of a first waveguide to produce positioning elements on the first surface.

[0099] Then, at step S530, any optical function region 25, 41, 42 is formed on one or more surfaces 23, 24 of the waveguides 21, 22, 4. For example, the optical function region 25 shown in FIG.

[0100] Alternatively, any optical functional area can be formed before or while performing NIL. However, in this case, when performing NIL, it must be ensured that the resist does not cover the optical functional area. In addition, in the case where there is no optical functional area on the surface where the positioning element is formed, the formation of the optical functional area can be omitted.

[0101] Then, at step S540, the waveguide is arranged using one or more positioning elements. As described above, the positioning elements can control the relative position of the surfaces of the waveguide and / or can control the position of the adhesive used to attach the surfaces together. For example, referring to Figure 2A , the first waveguide 21 is arranged at a fixed position relative to the second waveguide 22 using positioning elements 27 and 28 , wherein the first surface 23 at least partially faces the second surface 24 .

[0102] Figure 6 6 is a stereoscopic view of a user wearing a portion of an augmented reality headset in an embodiment of the present invention. In this example, an optical device 61 is provided in front of the user's eyes so that the user can view augmented reality images while continuing to see the physical world around them. The headset includes a projector 62 that is positioned to project light along the z-axis toward the optical device 61. A battery (not shown) is provided and supplies power to the projector 62. In addition, a frame (not shown) is provided for mounting the assembly on the user's head. Alternatively, the augmented reality headset can be a virtual reality headset that does not require the user to see light from their external environment.

[0103] In the above description, the optical device includes two waveguides. However, it will be readily appreciated that the above techniques may be applied to optical devices including any number of waveguides having one or more pairs of surfaces facing each other.

[0104] According to the above description, the embodiments of the present invention also disclose the following technical solutions, including but not limited to:

[0105] Solution 1. An optical device, comprising:

[0106] a first waveguide comprising a first surface; and

[0107] a second waveguide comprising a second surface,

[0108] wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, and

[0109] The first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography (NIL) structure,

[0110] The optical device further comprises an adhesive arranged to attach the first surface to the second surface,

[0111] Wherein, the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises:

[0112] an affinity region adapted to attract said adhesive; or

[0113] A repellent region adapted to repel the adhesive.

[0114] Option 2. An optical device according to Option 1, wherein the first positioning element is arranged to control the position of the second surface relative to the first surface.

[0115] Option 3. An optical device according to Option 2, wherein the first positioning element is arranged to control the spacing between the first surface and the second surface.

[0116] Option 4. An optical device according to any of the preceding options, wherein the second surface includes a second positioning element, and the second positioning element is a nanoimprint lithography (NIL) structure.

[0117] Option 5. An optical device according to any preceding option, wherein the second positioning element is adapted to engage with the first positioning element.

[0118] Option 6. An optical device according to any of the preceding options, wherein the first surface or the second surface includes an optically functional area, the first positioning element includes a barrier portion, the barrier portion is arranged to surround the optically functional area, and the adhesive is arranged on the first surface outside the barrier portion.

[0119] Option 7. An optical device according to any preceding option, wherein the adhesive is opaque.

[0120] Embodiment 8. An optical device according to any preceding embodiment, wherein the adhesive is adapted to control a spacing between the first surface and the second surface.

[0121] Option 9. An optical device according to Option 8, wherein the adhesive comprises microspheres or beads.

[0122] Embodiment 10. A method for manufacturing an optical device, the optical device comprising a first waveguide and a second waveguide, wherein the first waveguide is in a fixed position relative to the second waveguide, the method comprising:

[0123] performing nanoimprint lithography on a first surface of the first waveguide to produce positioning elements on the first surface;

[0124] arranging the first waveguide at a fixed position relative to the second waveguide using the positioning element, wherein the first surface at least partially faces the second surface; and

[0125] providing an adhesive for attaching the first surface to the second surface,

[0126] Wherein, the positioning element is arranged to control the position of the adhesive, and the positioning element comprises:

[0127] an affinity region adapted to attract said adhesive; or

[0128] A repellent region adapted to repel the adhesive.

Claims

1. An optical device, comprising: a first waveguide comprising a first surface; as well as a second waveguide comprising a second surface, wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, The first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography (NIL) structure; and The second surface includes a second positioning element, wherein the second positioning element is a nanoimprint lithography structure; The optical device further comprises an adhesive arranged to attach the first surface to the second surface, Wherein, the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises a repellent region adapted to repel the adhesive by having a higher contact angle with the adhesive than a surrounding area.

2. The optical device according to claim 1, wherein: The first positioning element is arranged to control a position of the second surface relative to the first surface.

3. The optical device according to claim 2, wherein: The first positioning element is arranged to control a spacing between the first surface and the second surface.

4. An optical device according to any preceding claim, wherein: The first surface or the second surface includes an optical function area, the first positioning element includes a barrier portion, the barrier portion is arranged to surround the optical function area, and the adhesive is arranged on the first surface outside the barrier portion.

5. The optical device according to any one of claims 1 to 3, wherein: The adhesive is opaque.

6. The optical device according to any one of claims 1 to 3, wherein: The adhesive is adapted to control a spacing between the first surface and the second surface.

7. The optical device according to claim 6, wherein: The binder comprises microspheres or beads.

8. A method for manufacturing an optical device, the optical device comprising a first waveguide and a second waveguide, wherein: The first waveguide is in a fixed position relative to the second waveguide, the method comprising: performing nanoimprint lithography on a first surface of the first waveguide to produce first positioning elements on the first surface; performing nanoimprint lithography on a second surface of the second waveguide to produce second positioning elements on the second surface; arranging the first waveguide at a fixed position relative to the second waveguide using the first positioning element and the second positioning element, wherein the first surface at least partially faces the second surface of the second waveguide; and providing an adhesive for attaching the first surface to the second surface, Wherein, the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises a repellent region adapted to repel the adhesive by having a higher contact angle with the adhesive than a surrounding area.

9. An optical device comprising: a first waveguide comprising a first surface; as well as a second waveguide comprising a second surface, wherein the first waveguide is in a fixed position relative to the second waveguide, wherein the first surface at least partially faces the second surface, The first surface comprises a first positioning element, wherein the first positioning element is a nanoimprint lithography (NIL) structure; and The second surface includes a second positioning element, wherein the second positioning element is a nanoimprint lithography structure; The optical device further comprises an adhesive arranged to attach the first surface to the second surface, Wherein, the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises an affinity region adapted to attract the adhesive by having a lower contact angle with the adhesive than a surrounding region.

10. The optical device according to claim 9, wherein: The first positioning element is arranged to control a position of the second surface relative to the first surface.

11. The optical device according to claim 10, wherein: The first positioning element is arranged to control a spacing between the first surface and the second surface.

12. An optical device according to any one of claims 9 to 11, wherein: The first surface or the second surface includes an optical function area, the first positioning element includes a barrier portion, the barrier portion is arranged to surround the optical function area, and the adhesive is arranged on the first surface outside the barrier portion.

13. An optical device according to any one of claims 9 to 11, wherein: The adhesive is opaque.

14. An optical device according to any one of claims 9 to 11, wherein: The adhesive is adapted to control a spacing between the first surface and the second surface.

15. The optical device according to claim 14, wherein: The binder comprises microspheres or beads.

16. A method for manufacturing an optical device, the optical device comprising a first waveguide and a second waveguide, wherein: The first waveguide is in a fixed position relative to the second waveguide, the method comprising: performing nanoimprint lithography on a first surface of the first waveguide to produce first positioning elements on the first surface; performing nanoimprint lithography on a second surface of the second waveguide to produce second positioning elements on the second surface; arranging the first waveguide at a fixed position relative to the second waveguide using the first positioning element and the second positioning element, wherein the first surface at least partially faces the second surface of the second waveguide; and providing an adhesive for attaching the first surface to the second surface, Wherein, the first positioning element is arranged to control the position of the adhesive, and the first positioning element comprises an affinity region adapted to attract the adhesive by having a lower contact angle with the adhesive than a surrounding region.

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