Imaging waveguide

Abstract

An optical waveguide combiner includes an optical waveguide substrate and an optical input region. The optical input region includes an optical input diffraction grating integrated in or disposed on the optical waveguide substrate. The optical output region includes an optical output diffraction grating integrated in or disposed on the optical waveguide substrate. At least one non-diffraction region includes at least one nanostructured optical non-diffraction array, wherein the at least one nanostructured optical non-diffraction array is integrated in or disposed on the object side of the optical waveguide substrate and at least partially surrounds at least the optical output grating; wherein the external visible reflectance of the at least one nanostructured non-diffraction array is substantially equal to the external visible reflectance of the optical output grating.

Description

[0001] Relevant application data

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 174,000, filed April 12, 2021, and U.S. Provisional Patent Application Serial No. 63 / 174,385, filed April 13, 2021, the contents of which are incorporated herein by reference as expressly stated. Technical Field

[0003] The present invention relates to imaging waveguides, and more particularly, but not exclusively, to imaging waveguide combiners including diffraction grating regions for augmented reality devices or mixed reality devices. Background Technology

[0004] Imaging waveguides for augmented reality devices (such as near-eye-based augmented reality (AR) devices) and mixed reality (MR) devices (such as mixed reality smart glasses applications) have been developed for at least two decades and have undergone continuous improvements during this period. Many improvements focus on enhancing functionality in both optical performance and wearer comfort. Significant efforts have been invested in reducing the shape factor of near-eye devices, making them look more like conventional ophthalmic glasses, while also making them lighter and therefore easier to use for extended periods. Attached Figure Description

[0005] To make this technology easier to understand, reference will now be made to the accompanying drawings, in which:

[0006] Figure 1 shows a cross-sectional view of a typical waveguide device in the prior art when the projector module is turned on, i.e., when the projector module projects an image carrying light.

[0007] Figure 2 depicts a perspective view of a prior art waveguide device as viewed by an observer when the projector module is turned off.

[0008] Figure 3 A perspective view of a waveguide device according to some embodiments, as viewed by an observer when the projector module is turned off.

[0009] Figure 4 Depicting, according to some implementation methods, from, such as Figure 3 An exemplary plan view of the waveguide device viewed from above, indicating different regions of the waveguide.

[0010] Figure 5 Cell elements representing surface patterns according to some implementations.

[0011] Figure 6 Depicting Figure 4The graph shows the light reflectance at different locations on the waveguide surface.

[0012] Figure 7 A cross-sectional view of a waveguide device according to some embodiments is shown when the projector module is turned on, i.e., when the projector module projects an image carrying light.

[0013] Figure 8 A cross-sectional view of a waveguide device according to some embodiments is shown when the projector module is turned off, i.e., when the projector module is not projecting an image and carrying light.

[0014] Figure 9 An optical waveguide combiner implemented in eyeglasses according to one aspect is shown.

[0015] Unless otherwise specified, the accompanying drawings referenced in this specification should be understood as not drawn to scale in order to illustrate the details of this disclosure more clearly. The same reference numerals in the drawings indicate the same elements in several views. Other features and advantages of this disclosure will become apparent from the drawings and the following detailed description. Detailed Implementation

[0016] In the following description, specific details, such as particular embodiments, processes, techniques, etc., are set forth for purposes of explanation and not limitation, in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced in other embodiments departing from these specific details.

[0017] One less-discussed aspect of waveguide design involves the visible appearance of diffractive elements forming the effective image-carrying region of the waveguide to a bystander. This disclosure describes structures and features that improve the aesthetic appearance of waveguides used in AR or MR smart glasses for bystanders and other types of AR and MR devices such as head-up display systems in automobiles or other vehicles.

[0018] The improved uniformity of visible reflectivity on the surface of the waveguide combiner masks the presence of the embossed grating region on the diffractive surface to an observer.

[0019] The object side of an optical waveguide combiner is defined herein as the side of the combiner that is identical to a real-world object, which can be viewed by the user of the optical waveguide combiner through the combiner. The eye side of an optical waveguide combiner is defined herein as the side of the combiner that is identical to the eye-tracking box of the combiner.

[0020] Figure 1 illustrates the working principle of an augmented reality (AR) or mixed reality (MR) see-through display. First, a projected image is generated by the projector module 1. The resulting image carries light 2, which is coupled to a transparent waveguide substrate 3 via an input region 4. The light then undergoes total internal reflection within the waveguide substrate and is finally coupled out of the waveguide substrate via an output region 5 toward the user's eye 6. Simultaneously, the user perceives their surrounding environment 7 by transmitting a corresponding set of light rays 8 through the transparent waveguide substrate 3 toward their eye 6.

[0021] Figure 2 depicts a perspective view of a prior art waveguide combiner 10 for displaying information in an augmented reality (AR) or mixed reality (MR) configuration in smart glasses. The waveguide combiner 10 has an input region 11, an output region 12, and a region in which a polymer layer 13 has a smooth surface profile. A transparent waveguide substrate 10A is formed from a planar glass sheet having a high degree of surface flatness, uniform thickness, and defined refractive index. One main surface of the waveguide combiner 10 is coated with a refractive index-matched polymer layer 13, while the other main surface is covered with an anti-reflective coating. The input region 11 and the output region 12 are imprinted into the polymer layer 13 using a nanoimprint lithography process. Thus, the input region 11 and the output region 12 are diffractive surface relief gratings: the input region 11 presents a linear or pseudo-linear grating (as shown in enlarged view 16 representing the input region 11), while the output region 12 is a cross grating (as shown in enlarged view 17 representing the output region 12). Input region 11 is designed to diffract the image-carrying light (from projector module 15) directed thereto into waveguide combiner 10. The image-carrying light coupled to the transparent waveguide substrate 10A is directed to output region 12 via total internal reflection, through which a person wearing glasses, a head-mounted device, or other head-mounted or near-eye device (which positions the waveguide in front of the eye 14) can perceive the image carried by the image-carrying light. Commonly owned application US Patent Application Publication 2020 / 0110261 (the contents of which are incorporated herein by reference) describes the operating principle of such waveguide combiner 10 as follows: a single input pupil of the image-carrying light entering input region 11 is replicated as multiple output pupils displayed over the magnified eye-tracking box range of output region 12.

[0022] Any portion of the polymer layer 13 that is not imprinted with a surface relief grating structure has a smooth surface profile (as shown in enlarged view 18, illustrating the absence of a structure and therefore no smooth surface profile). The region of the polymer layer 13 with the smooth surface profile occupies the main surface of the waveguide combiner 10 that is not patterned through the input region 11 and the output region 12. The presence of the output region 12 is particularly noticeable when an individual, i.e., an observer 19 on the object side of the optical combiner / device opposite the user's eye side, approaches a person wearing a head-mounted device including at least one waveguide combiner 10, due to the difference in visible reflectivity of the surface regions on the waveguide combiner 10.

[0023] Figure 3 A perspective view of a waveguide combiner 20 according to some embodiments is depicted. The waveguide combiner 20 has an optical waveguide substrate 20A, a light input region 21, a light output region 22 (the location of which is indicated by a dashed outline), and a polymer layer 23 with an imprinted region of a non-diffractive array of nanostructures (as shown in enlarged view 28). This non-diffractive array of nanostructures modulates the surface reflectivity of the waveguide combiner 20 (when the projector module 25 is off) and has no or negligible effect on image-carrying light undergoing total internal reflection within the transparent waveguide substrate 20A (when the projector module is on, as shown in enlarged view 28). Figure 7 (As shown in the diagram). The non-diffractive array of nanostructures has a size smaller than the wavelength of image-carrying light that undergoes total internal reflection within the transparent waveguide substrate 20A, such that they do not diffract such image-carrying light.

[0024] In some implementations, when the non-diffractive array of the nanostructure causes up to 2% of any wavelength of the image-carrying light to diffract into a diffraction order, the non-diffractive array of the nanostructure is considered to have essentially no effect on the total internal reflection of the image-carrying light from the projector module.

[0025] The region with the non-diffractive array of nanostructures imprinted occupies the main surface of the transparent waveguide substrate not occupied by the input region 21 and the output region 22. The input region 21 is a linear or pseudo-linear diffraction grating (as shown in enlarged view 26 representing the input region 21), while the output region 22 is a cross-diffraction grating (as shown in enlarged view 27 representing the output region 22). In some embodiments, the input grating is a cross-diffraction grating, and the output grating is a linear or pseudo-linear grating. In some embodiments, the input grating is a cross-diffraction grating, and the output grating is a cross-diffraction grating. In some embodiments, the input grating is a linear or pseudo-linear grating, and the output grating is a linear or pseudo-linear grating. Similar to FIG. 2, image-carrying light is directed to the input region 21, which diffracts the light into the transparent waveguide substrate 20A and directs it toward the output region 22, which replicates the input pupil onto an enlarged eye-tracking box region present on the output region 22, through which the wearer perceives the image present in the input pupil.

[0026] Unlike the prior art device described in Figure 2, the polymer layer 23, which is not imprinted with the input region 21 or the output region 22, is imprinted with a nanostructure array whose size, shape, and spacing are determined such that the array is non-diffractive, thereby having no or negligible effect on the image-carrying light undergoing total internal reflection within the transparent waveguide substrate 20A (when the projector module is on, such as...). Figure 7 (As shown). The presence of such a non-diffractive array of nanostructures on the object-side surface of waveguide 20 modulates the visible reflection of the surface, such that, unlike the prior art devices depicted in Figure 2, the appearance of waveguide combiner 20 to the observer 29 is uniformly reflected when projector module 25 (close to the user's eye 24) is off. Figure 3 In this design, the input region 21, the output region 22, and the region with the imprinted non-diffractive array of nanostructures exhibit similar surface reflectivity on the non-eye side. This makes the diffractive regions, i.e., the input region 21 and the output region 22, less noticeable to an observer. In some embodiments, the polymer layer 23 may be replaced by an optical coating such as titanium dioxide or silicon nitride, patterned to define the input region 21, the output region 22, and the non-diffractive region; and in other embodiments, the polymer layer 23 is absent, and the glass surface of the waveguide is directly structured or patterned with diffraction gratings and a non-diffractive array of nanostructures. The nanostructures can be defined in the optical coating or the glass surface, respectively, using chemical or wet etching with a protective mask produced by a suitable photolithography technique. Alternatively, electron beam or other etching techniques may be used.

[0027] In some other embodiments, any one or a combination of the light input region, the light output region, and the non-diffraction region is integrated with or disposed on the optical waveguide substrate by other means.

[0028] Once the nanostructure has been defined by nanoimprinting of the polymer layer or by etching of the surface, another conformal optical coating can be applied to the entire surface of the waveguide combiner 20 that has been patterned with the nanostructure.

[0029] Figure 4 It shows from Figure 3 The image depicts a plan view of the waveguide combiner 20 from above, showing details of the various patterned nanostructures. The input region 21 is provided as a linear or pseudo-linear diffraction grating, which is typically configured to diffract image-bearing light orthogonally oriented to the surface of the input region 21 into the transparent waveguide substrate 20A and to direct the light toward the output region 22.

[0030] However, in some cases, depending on the specific design of the system, the image-carrying light can be introduced at an angle other than 90 degrees to the surface. Output region 22 includes a photonic crystal or cross-diffraction grating structure configured to replicate the input pupil of the image-carrying light in two dimensions over a region of the output region, and direct the replicated pupil toward the eyes of a person viewing through waveguide combiner 20, allowing them to perceive the information conveyed by the image-carrying light while simultaneously viewing the real world through the waveguide. Any remaining surface of waveguide combiner 20 not patterned by the diffraction structure is patterned by an array of 30-nanometer cell structures of sufficiently small size (see...). Figure 4 and Figure 5 This is to prevent diffraction of image-carrying light propagating within the transparent waveguide substrate via total internal reflection. The visible reflection of the non-diffractive array of cell 30 nanometer structures can be modulated through specific design variations, including modulating the spacing, profile shape, and size of such structures; assuming the size remains small enough to have little or no impact on the image-carrying light guided into the transparent waveguide substrate 20A via input region 21. In some embodiments, the non-diffractive array of cell 30 nanometer structures is considered to have little impact on the total internal reflection of image-carrying light from the projector module if at most 2% of any wavelength of the image-carrying light is diffracted into a diffraction order by the non-diffractive array of cell 30 nanometer structures. Therefore, the design characteristics of the cell 30 nanometer structures can be modulated to ensure that the surface reflectivity closely matches the surface reflectivity of the diffractive structures present in input region 21 and output region 22.

[0031] The presence of such a non-diffractive array of 30-nanometer cell structures is sufficient to alter the reflectivity of the surface of the waveguide combiner 20 (on which input region 21 and output region 22 exist) to achieve a uniform reflectivity on the object-side surface of the waveguide combiner. Thus, the non-diffractive array of 30-nanometer cell structures is designed to mask or disguise the presence of a diffraction grating (when the projector module 25 is off) by mimicking the surface reflection characteristics of a diffraction grating. The result of this surface modification is that, for an individual viewing an appearance-enhanced waveguide-based eyeglass (see user's eye 24), (e.g., Figure 3 The presence of bystanders (29) reduces the originally obvious appearance, especially the appearance of the output region 21. The input region is typically hidden from the user and bystanders by the frame supporting the waveguide combiner. Therefore, in some embodiments, it may only be necessary to disguise the output region. In other embodiments, the input region is not hidden, and a non-diffractive array of nanostructures is used to disguise both the input and output regions. In some embodiments, optical non-diffractive nanostructures completely or partially surround the optical output grating and / or the optical input grating.

[0032] Figure 5 This refers to a non-diffractive cell element 30 according to some embodiments, which can be used in any of the waveguide embodiments disclosed herein. The non-diffractive cell element 30 is patterned in a checkerboard pattern on the surface of the waveguide 20, outside the input region 21 and the output region 22, both of which are patterned using a diffraction grating structure. In some embodiments, the cell 30 includes a central region 32 with a depth between 15 nm and 100 nm and a cross-sectional dimension between 15 nm and 75 nm, while the outer region of the cell 30 has a length between 25 nm and 200 nm in the x-direction and a length between 25 nm and 200 nm in the y-direction. In an exemplary embodiment, the cell 30 has a length of 100 nm in the x-direction and a length of 100 nm in the y-direction, wherein the central region 22 has a diameter of 58 nm and a depth of 55 nm. Therefore, as... Figure 4As shown, the central region 32 of cell 30 can be obtained by imprinting "holes" in polymer layer 23 or etching holes in the glass or optical coating of waveguide 20. When viewed from above the waveguide, the "hole" can be circular, as it is the shape most easily obtained via the manufacturing process. Alternatively, the "hole" can be any polygon-based shape. The central region 32 of cell 30 can have any spacing, shape, and size, as long as these dimensional parameters are sufficiently smaller than the wavelength of visible light to prevent any unwanted diffraction of the image-carrying light undergoing total internal reflection within the transparent waveguide substrate. In some embodiments, the non-diffractive array of the nanostructures of cell 30 causes at most 2% of any wavelength of the projector module light carrying the image to be diffracted into a diffraction order. Thus, this is considered to indicate that there is essentially no effect on the total internal reflection of the image-carrying light from the projector module. In some other implementations, the cell dimensions, including the dimensions of the outer and / or central regions, may differ from those specifically mentioned, as long as the nanostructure substantially prevents any unwanted diffraction of image-carrying light undergoing total internal reflection within the transparent waveguide substrate, while ensuring that the surface visible reflectivity of the waveguide assembly is similar across the entire surface.

[0033] For a non-diffractive 30-nanometer array of cell structures, the spacing d between the "holes," i.e., the period of the non-diffractive array of nanostructures, must follow the following inequality:

[0034] Where α is the angle of incidence, λ is the wavelength, and n is the refractive index of the waveguide. This condition must be satisfied for all propagation angles of the image-carrying light within the waveguide.

[0035] The reflectivity R from a non-diffractive array derived from a nanostructure can be calculated as follows:

[0036] in,

[0037]

[0038] Where, r 12 r 21 and r 23 This is the Fresnel reflection coefficient used for the interface between layers in a layered system. The Fresnel coefficients for s- and p-polarized light are given by the following equation:

[0039]

[0040] Where n1 and n2 are the refractive indices of the material. The refractive index of the metamaterial corresponding to the non-diffractive array of the nanostructure can be approximated as...

[0041]

[0042] Where β is the fill fraction of the structure within the cell.

[0043] In some implementations, when the input region 21 is much smaller than the output region 22 and the region of the non-diffractive array with the cell structure 30 imprinted, an observer will not be able to see the input grating 21.

[0044] For the region of the non-diffractive array imprinted with 30-nanometer cell structures to masquerade as output region 22, its visible external reflection must exhibit an acceptable level similar to the visible external reflectivity of the output region. In some embodiments, a similar acceptable level is defined as a visible reflection contrast of less than 1.5% for an incident angle from 0 degrees to 60 degrees.

[0045] Visible reflectance is defined as

[0046]

[0047] Where R is the surface reflectance, L is the luminous efficiency function, and S is the illumination spectrum. In some other embodiments, an acceptable level of similarity is defined as not less than 1.5%, but such that the non-diffractive structure essentially masquerades as the output region 22.

[0048] The patterning of the surface of the waveguide combiner 20 with the non-diffractive array of the input region 21, output region 22, and cell 30 nanometer structures can be performed in a single operation using a range of techniques, including but not limited to nanoimprint lithography, reactive ion etching, electron beam etching, and chemical etching, as known in the art. In the case of nanoimprint lithography, a master imprint pattern is prepared in an imprinting tool, which is imprinted onto the polymer layer 23 in a single step. Therefore, misalignment of the individual patterned regions does not occur. Consequently, the resulting imprinted waveguide combiner 20 can be mass-produced with high precision and high uniformity between devices. In the case of an etching process, the entire surface of the waveguide combiner 20 can be patterned again in a single operation.

[0049] Figure 6 The light reflectance (i.e., visible reflectance) of an embodiment in which polymer layer 23 is provided on the surface of waveguide 20 is depicted relative to the light reflected from the eye of a person viewing through the waveguide (i.e., the user's eye). Figure 3 A graph of the angle of incidence of external illumination light (that is, non-image-carrying light specifically directed into the input area 21) on the outer surface of the user's eye 24). Figure 6 The visible reflectance of the imprinted surface regions of the waveguide 20, including the unimprinted polymer layer 23 (rhomboid), output region 22 (triangular), and cell 30 (circular), is shown. (By...) Figure 6Multiplying the visible reflectance values ​​of the curves by 100 yields their corresponding percentages. Then, by subtracting the visible reflectance values ​​(expressed as percentages) of the curves of interest, it can be determined whether they are below or above an acceptable level of similarity. In some implementations, an acceptable level of similarity is defined as a visible light reflectance contrast of less than 1.5% for incident angles from 0 to 60 degrees.

[0050] The non-impregnated polymer layer 23 (rhomboid) exhibits the highest light reflectivity at all incident angles; while (after the imprinting of diffractive surface relief gratings in input region 21 and output region 22 and non-diffractive surface relief gratings outside input region 21 and output region 22), the region (circular) of waveguide 20 with imprinted cells 30 shows excellent consistency with the light reflectivity of output region 22 (triangular), i.e., their visible light reflectivity difference is less than 1.5%; thus indicating that for all incident angles, output region 22 (triangular) has a similar light reflectivity to the surrounding region which has been imprinted with non-diffractive cells 30 (circular). Therefore, the presence of non-diffractive cells 30 (circular) alters the reflective appearance of waveguide 20, making output region 22 (triangular) more reflective to an observer 29 (such as...). Figure 3 (As shown) This is not very visible, thus improving the aesthetic appearance of smart glasses with such an improved waveguide when the projector module 25 is off, without compromising the functional performance regarding the presentation of information contained in the image-carrying light, which is introduced into the waveguide 20 when the projector module 25 is on.

[0051] Figure 7 The diagram illustrates how image-carrying light 32 from projector 31 propagates within a waveguide in some embodiments. The main surface of the transparent waveguide substrate 33 supports the input region 34, the output region 35, and a region 39 (which occupies the main surface of the transparent waveguide substrate 33 excluding the input and output regions 34 and 35) imprinted with a non-diffractive array of cell 30 nanometer structures, as shown in the enlarged view 42 representing region 39. As depicted in the enlarged view 40 representing the input region 34, the input region 34 is imprinted with a linear or pseudo-linear diffraction grating; while the output region 35 is imprinted with a diffraction cross grating (as shown in the enlarged view 41 representing the output region 35).

[0052] Image-carrying light 32 generated by projector module 31 is coupled into transparent waveguide substrate 33 via input region 34, undergoes total internal reflection within the waveguide substrate, and is finally coupled out of the waveguide substrate via output region 35 toward user eye 36. Simultaneously, the user perceives their surrounding environment 37 via a group of related light rays 38 transmitted through transparent waveguide substrate 33 toward user eye 36. The array of non-diffractive structures of cell 30 imprinted in region 39 has virtually no effect on the image-carrying light undergoing total internal reflection within transparent waveguide substrate 33.

[0053] exist Figure 8 The image shows the situation with the projector off. Figure 7 The optical waveguide combiner does not carry light from an image from a projector. The main surface of the transparent waveguide substrate 33 includes an input region 34, an output region 35, and a region 39 (which occupies the main surface of the transparent waveguide substrate 33 excluding the input and output regions 34 and 35) with a non-diffractive array of cell 30 nanometer structures imprinted as shown in the enlarged view 42 representing region 39. As depicted in the enlarged view 40 representing input region 34, the input region 34 is imprinted with a linear or pseudo-linear diffraction grating; while the output region 35 is imprinted with a diffraction cross grating (as shown in the enlarged view 41 representing output region 35).

[0054] The user perceives their surroundings 37 through a set of 38 rays transmitted through the transparent waveguide substrate 33 toward the user's eye 36. Region 39 exhibits a similar visible reflectivity to the output region 35, such that region 39 masks the output region 35: (see element 43, which represents a set of identical rays from the user's surroundings, reflected in the same manner on the input region 34, output region 35, and region 39, so as to have similar visible reflectivity for an observer, which is in Figure 8 (Not shown in the image).

[0055] In other embodiments, the optical combiner of any of the embodiments described above may include one or more second non-diffractive arrays of nanostructures configured to have a visible reflectance different from that of the output region and other non-diffractive arrays of nanostructures. The second non-diffractive array of nanostructures represents a predetermined pattern on the object side of the optical waveguide combiner, such as, but not limited to, a logo or trademark. In some embodiments, the second non-diffractive array of nanostructures is configured such that the visible reflectance contrast between one or more second non-diffractive arrays of nanostructures and other non-diffractive arrays of nanostructures exceeds 1.5%.

[0056] According to some aspects, a near-eye optical display system is provided. This near-eye optical display system may include any of the optical waveguide combiners of the embodiments described herein. In some aspects, any of the optical waveguide combiners of the embodiments described herein can be implemented in a near-eye optical display system having an eyeglass shape factor. In some embodiments, the near-eye optical display system has a light engine (projector or other light engine), a battery, and an optical waveguide combiner of any of the embodiments described herein. The near-eye optical display system may be an AR or MR optical display system. As an example, such as Figure 9 As shown, the near-eye optical display system includes an optical projector 1002, an optical waveguide combiner 1001 (which may be an optical waveguide combiner according to any of the embodiments disclosed herein), and a battery 1003. The optical projector 1002 is optically coupled to the optical waveguide combiner and electrically coupled to the battery 1003. The optical projector, optical waveguide combiner, and battery are mounted on the frame of the eyeglasses, and for example, as shown in the diagram. Figure 9 The layout is shown.

[0057] The following are examples of systems, devices, and methods taught in accordance with this disclosure.

[0058] Example 1 is an optical waveguide combiner, comprising: an optical waveguide substrate; an optical input region; wherein the optical input region includes an optical input diffraction grating integrated in or disposed on the optical waveguide substrate; an optical output region; wherein the optical output region includes an optical output diffraction grating integrated in or disposed on the optical waveguide substrate; and at least one non-diffraction region; wherein the at least one non-diffraction region includes at least one nanostructured optical non-diffraction array, wherein the at least one nanostructured optical non-diffraction array is integrated in or disposed on the object side of the optical waveguide substrate and at least partially surrounds at least the optical output grating; wherein the external visible reflectance of the at least one nanostructured non-diffraction array is substantially equal to the external visible reflectance of the optical output grating.

[0059] Example 2 includes Example 1, wherein the total internal reflection of image-carrying light capable of propagating from the light input region to the light output region within the optical waveguide substrate is substantially unaffected by the non-diffractive array of the nanostructure.

[0060] Example 3 includes Example 1 or 2, wherein the refractive index of the nanostructured optical non-diffractive array is substantially matched with the refractive index of the optical waveguide substrate.

[0061] Example 4 includes Example 1, 2, or 3, wherein the optical non-diffractive array of the nanostructure or a plurality of the non-diffractive arrays of the nanostructure completely surrounds the light output diffraction grating and / or the light input diffraction grating; and wherein the external visible reflectance of the at least one non-diffractive array of the nanostructure is substantially equal to the external visible reflectance of at least the light output diffraction grating and / or the light input diffraction grating.

[0062] Example 5 includes any one of Examples 1, 2, 3, or 4, wherein the optical waveguide substrate includes a first side and a second side opposite to the first side; wherein, when in use, the first side is the eye side of the optical waveguide combiner, and the second side is the object side of the optical waveguide combiner; wherein a coating is applied to the second side of the optical waveguide substrate; wherein the at least one light input region includes a linear surface relief grating patterned in the coating; wherein the at least one light output region includes a surface relief grating patterned in the coating; and wherein the non-diffractive region includes an additional region of the coating patterned with a non-diffractive array of the nanostructure and surrounds the light input region and / or the light output region.

[0063] Example 6 includes Example 5, wherein the coating has a refractive index substantially the same as that of the waveguide substrate.

[0064] Example 7 is an improved imaging waveguide for augmented reality (AR) or mixed reality (MR) devices, comprising: a waveguide having a first primary surface and a second primary surface; an antireflective coating applied to the first primary surface of the waveguide; and a coating applied to the second primary surface of the waveguide, wherein the coating has a refractive index substantially the same as that of the waveguide and includes a first region patterned with a linear surface relief grating and a second region patterned with a two-dimensional surface relief grating; characterized in that the coating further comprises an additional region patterned with a non-diffractive array of nanostructures, the additional region being disposed across the surface of the waveguide surrounding the first and second regions, wherein the additional patterned region is configured to exhibit an external visible reflectance substantially the same as that of the region patterned with a diffractive surface relief grating, while having minimal impact on the total internal reflection of image-carrying light introduced via the first linear surface relief grating and guided out of the waveguide via the two-dimensional surface relief grating.

[0065] Example 8 includes any one of Examples 1 to 7, wherein the non-diffractive region or additional patterned region comprises a non-diffractive array of repeating unit nanostructures.

[0066] Example 9 includes Example 8, wherein each of the repeating unit nanostructures has an outer edge dimension of at least 50 nm, at least 75 nm, at least 100 nm, at least 125 nm, at least 150 nm, at least 175 nm, or at least 200 nm.

[0067] Implementation 10 includes implementation 8, wherein each of the repeating unit nanostructures has an internal feature diameter of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, or at least 100 nm.

[0068] Example 11 includes Example 8, wherein each of the repeating nanostructures has internal features with depths of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, and at least 100 nm.

[0069] Example 12 includes Example 8, wherein each of the repeating unit nanostructures has an exemplary outer edge dimension of 100 nm; and the internal features have a cross-sectional dimension of 58 nm and a depth of 55 nm.

[0070] Example 13 includes any of Examples 1 to 12, wherein the coating has a refractive index different from that of the waveguide.

[0071] Example 14 includes any one of Examples 1 to 13, and further includes a second non-diffractive array of at least one nanostructure having a visible reflectance different from that of the output region and another non-diffractive array of the nanostructure; the second non-diffractive array of the at least one nanostructure defines a predetermined pattern visible on the object side of the optical waveguide combiner; wherein optionally, the pattern is a logo or trademark.

[0072] Example 15 includes Example 14, wherein the visible reflectance contrast between the second non-diffractive array of the at least one nanostructure and another non-diffractive array of the nanostructure exceeds 1.5% visible reflectance contrast.

[0073] Example 16 is a method for modifying the surface visible reflectivity of an imaging waveguide to blur the presence of a surface relief grating, comprising: providing a waveguide having a first principal surface and a second principal surface; patterning a linear surface relief grating in a first region of the first principal surface; patterning a two-dimensional surface relief grating in a second region of the first principal surface; and

[0074] Another structure is patterned on the unpatterned area of ​​the first main surface with a linear or two-dimensional surface relief grating. The other structure is a non-diffractive array of nanostructures. The other structure, which is a non-diffractive array of nanostructures, is configured to exhibit a surface visible reflectance that is substantially the same as that of the linear or two-dimensional surface relief grating, thus blurring the appearance of the surface relief grating.

[0075] Example 17 includes Example 16, wherein the other structure comprises a non-diffractive array of repeating unit nanostructures.

[0076] Example 18 includes Example 17, wherein each of the repeating unit nanostructures has an outer edge dimension of at least 50 nm, at least 75 nm, at least 100 nm, at least 125 nm, at least 150 nm, at least 175 nm, or at least 200 nm.

[0077] Implementation 19 includes Example 17, wherein each of the repeating unit nanostructures has internal features of a size of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, or at least 100 nm.

[0078] Example 20 includes Example 17, wherein each of the repeating unit nanostructures has internal features with depths of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, and at least 100 nm.

[0079] Implementation 21 includes implementation 17, wherein each of the repeating unit nanostructures has an exemplary outer edge dimension of 100 nm; and an exemplary internal feature having a cross-sectional dimension of 58 nm and a depth of 55 nm.

[0080] Example 22 includes any one of Examples 16 to 21, wherein the step of patterning the coating applied to the waveguide surface is replaced by a process of directly etching the main surface of the waveguide to define nanostructure features.

[0081] Example 23 is a near-eye optical display system, comprising: a light engine; and a waveguide as described in any of Examples 1 to 15 above.

[0082] Example 24 includes Example 23, wherein the near-optical display system includes an augmented reality display system.

[0083] Example 25 includes Example 23, wherein the near-optical display system includes a mixed reality display system.

[0084] Example 26 includes any of Examples 23 to 25, wherein the light engine and waveguide are mounted on the eyeglass frame.

[0085] Example 27 is a head-up display system comprising: a light engine; and a waveguide as in any of Examples 1 to 15.

[0086] Example 28 is a method for modifying the visible light reflectance of a surface of an optical waveguide assembly to obscure the presence of a surface relief grating. The method includes: providing an optical waveguide assembly comprising an optical waveguide substrate, an optical input region, and an optical output region, wherein the optical input region includes an optical input diffraction grating integrated in or disposed on the optical waveguide substrate; and wherein the optical output region includes an optical output diffraction grating integrated in or disposed on the optical waveguide substrate; and forming at least one non-diffraction region; wherein forming the at least one non-diffraction region includes: disposing or integrating at least one optical non-diffraction array of nanostructures on the object side of the optical waveguide substrate and at least partially surrounding at least the optical output grating; wherein the external visible reflectance of the non-diffraction array of the at least one nanostructure is substantially equal to the external visible reflectance of the optical output grating on the object side of the optical waveguide assembly.

[0087] Example 29 includes Example 28, wherein the total internal reflection of image-carrying light propagating from the light input region to the light output region within the optical waveguide substrate is substantially unaffected by the non-diffractive array of the nanostructure.

[0088] The present invention has been presented for purposes of illustration and description, but this description is not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Exemplary embodiments were chosen and described in order to best explain the principles of the invention and its practical application, and to enable others skilled in the art to understand various embodiments of the invention with various modifications suitable for the particular purpose considered.

[0089] Throughout this specification, references to "one embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the phrases "in one embodiment," "in an embodiment," or "according to one embodiment" (or other phrases with similar meanings) appearing in various places throughout this specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in one or more embodiments in any suitable manner. Additionally, depending on the context discussed herein, singular terms may include their plural forms, and plural terms may include their singular forms.

[0090] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms (“a,” “an,” and “the”) are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “including” are used in this specification, they specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0091] If any disclosure is incorporated herein by reference and such incorporated disclosure conflicts in whole or in part with this disclosure, then this disclosure shall prevail for the purposes of conflict, and / or the broader disclosure, and / or the broader definitions of terms. If any such incorporated disclosure conflicts in whole or in part with each other, then the later-date disclosure shall prevail for the purposes of conflict.

[0092] The terms used herein may imply direct or indirect, whole or part, temporary or permanent, immediate or delayed, synchronous or asynchronous, or action or non-action. For example, when an element is referred to as being “on,” “connected,” or “coupled” to another element, the element may be directly on, directly connected to, or directly coupled to the other element, and / or there may be intermediate elements, including indirect and / or direct variations. Conversely, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intermediate elements. The descriptions herein are illustrative and not restrictive. Many variations of the technology will become apparent to those skilled in the art upon reading this disclosure.

[0093] It should be understood that the various features and functions disclosed above, and others, or their alternatives, can be ideally combined into many other different systems or applications (e.g., head-up displays). Those skilled in the art can then make various alternatives, modifications, variations, or improvements that are not currently foreseen or anticipated, and these are also intended to be covered by the appended claims. For example, the head-mounted display device can be glasses, goggles, or a headband structure, and is not limited to the specific type shown in the figures. Similarly, the shape of the optical combiner substrate can be any shape capable of guiding and combining images in the manner described above.

[0094] The description of this disclosure has been presented for purposes of illustration and description, but it is not intended to be exhaustive or to limit the disclosure to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of this disclosure. Exemplary embodiments have been chosen and described in order to best explain the principles of this disclosure and its practical application, and to enable others skilled in the art to understand various embodiments of this disclosure with various modifications suitable for the particular purpose considered.

[0095] While various embodiments have been described above, it should be understood that they are presented by way of example only and not as limitations. These descriptions are not intended to limit the scope of the technology to the specific forms set forth herein. Therefore, the breadth and scope of preferred embodiments should not be limited by any of the exemplary embodiments described above. It should be understood that the above description is illustrative and not restrictive. Rather, this specification is intended to cover alternatives, modifications, and equivalents that may be included within the spirit and scope of the technology defined by the appended claims, as well as others understood by those skilled in the art. Therefore, the scope of the technology should not be determined by reference to the above description, but rather by the full scope of the appended claims and their equivalents.

Claims

1. An optical waveguide combiner, comprising: Optical waveguide substrate; The light input region includes a light input diffraction grating integrated in or disposed on the optical waveguide substrate. A light output region, wherein the light output region includes a light output diffraction grating integrated in or disposed on the optical waveguide substrate; and At least one non-diffraction region, wherein the at least one non-diffraction region comprises at least one nanostructured optical non-diffraction array, wherein the at least one nanostructured optical non-diffraction array is integrated in or disposed on the object side of the optical waveguide substrate and at least partially surrounds at least the light output diffraction grating, wherein the external visible reflectance of the at least one nanostructured optical non-diffraction array is substantially equal to the external visible reflectance of the light output diffraction grating.

2. The optical waveguide combiner according to claim 1, wherein, The total internal reflection of image-carrying light that can propagate from the light input region to the light output region within the optical waveguide substrate is substantially unaffected by the optical non-diffractive array of the at least one nanostructure.

3. The optical waveguide combiner according to claim 1 or 2, wherein, The refractive index of the optical non-diffractive array of at least one nanostructure is substantially matched with the refractive index of the optical waveguide substrate.

4. The optical waveguide combiner according to claim 1, wherein, The at least one nanostructured optical non-diffractive array completely surrounds the light output diffraction grating and / or the light input diffraction grating; and wherein the external visible reflectance of the at least one nanostructured optical non-diffractive array is substantially equal to the external visible reflectance of at least the light output diffraction grating and / or the external visible reflectance of the light input diffraction grating.

5. The optical waveguide combiner according to any claim 1, wherein, The optical waveguide substrate includes a first side and a second side opposite to the first side; wherein, in use, the first side is the eye side of the optical waveguide assembly, and the second side is the object side of the optical waveguide assembly, and wherein a coating is applied to the second side of the optical waveguide substrate. Wherein, the at least one light input region includes a linear surface relief grating patterned in the coating; Wherein, the at least one light output region includes a surface relief grating patterned in the coating; and The non-diffraction region includes an additional region of the coating patterned using a non-diffraction array of the at least one nanostructure and surrounding the light input region and / or the light output region.

6. The optical waveguide combiner according to claim 5, wherein, The coating has a refractive index that is substantially the same as that of the waveguide substrate.

7. An imaging waveguide for an augmented reality (AR) or mixed reality (MR) device, comprising: A waveguide having a first main surface and a second main surface, and an anti-reflection coating applied to the first main surface of the waveguide; as well as A coating applied to the second main surface of the waveguide, wherein the coating has a refractive index substantially the same as that of the waveguide, and comprises a first region patterned using a linear surface relief grating and a second region patterned using a two-dimensional surface relief grating; The coating further includes additional regions patterned using a non-diffractive array of nanostructures, the additional regions being disposed across the surface of the waveguide surrounding the first and second regions, wherein the additional regions are configured to exhibit substantially the same external visible reflectance as the regions patterned using a diffractive surface relief grating, while having minimal impact on the total internal reflection of image-carrying light introduced via the linear surface relief grating and guided out of the waveguide via the two-dimensional surface relief grating.

8. The waveguide according to claim 7, wherein, The additional region patterned using a non-diffraction array of nanostructures includes a non-diffraction array of unit nanostructures.

9. The waveguide according to claim 8, wherein, Each of the non-diffractive arrays of the unit nanostructures has an outer edge size of at least 50 nm, at least 75 nm, at least 100 nm, at least 125 nm, at least 150 nm, at least 175 nm, or at least 200 nm.

10. The waveguide according to claim 8, wherein, Each of the non-diffractive arrays of the unit nanostructures has an internal feature diameter of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, or at least 100 nm.

11. The waveguide according to claim 8, wherein, Each of the non-diffractive arrays of the nanostructures has internal features with depths of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, and at least 100 nm.

12. The waveguide according to claim 8, wherein, Each of the non-diffractive arrays of the unit nanostructures has an outer edge dimension of 100 nm and an internal feature with a cross-sectional dimension of 58 nm and a depth of 55 nm.

13. The waveguide according to claim 8, wherein, The coating has a different refractive index compared to that of the waveguide.

14. The waveguide of claim 8, further comprising at least one second non-diffractive array of nanostructures having a visible reflectance different from the visible reflectance of the additional region patterned using the non-diffractive array of nanostructures; the second non-diffractive array of at least one nanostructure defines a predefined pattern visible on the object side of the waveguide.

15. The waveguide according to claim 14, wherein, The visible reflectance contrast between the second non-diffractive array of the at least one nanostructure and the additional region patterned using the non-diffractive array of the nanostructure exceeds 1.5%.

16. A method for modifying the visible reflectivity of a surface of an imaging waveguide to obscure the presence of a surface relief grating on the surface, the method comprising: Provide a waveguide having a first principal surface and a second principal surface. A linear surface relief grating is patterned in a first region of the first main surface; A two-dimensional surface relief grating is patterned in the second region of the first main surface; as well as Another structure is patterned on an unpatterned area of ​​the first main surface with a linear or two-dimensional surface relief grating, the other structure being a non-diffractive array of nanostructures; The other structure, which is a non-diffractive array of nanostructures, is configured to exhibit a visible reflectance substantially the same as that of the linear surface relief grating or the two-dimensional surface relief grating, thereby obscuring the appearance of the surface relief grating on the first main surface.

17. The method according to claim 16, wherein, The other structure includes a non-diffractive array of repeating unit nanostructures.

18. The method according to claim 17, wherein, Each of the repeating unit nanostructures has an outer edge dimension of at least 50 nm, at least 75 nm, at least 100 nm, at least 125 nm, at least 150 nm, at least 175 nm, or at least 200 nm.

19. The method of claim 17, wherein, Each of the repeating unit nanostructures has internal features with dimensions of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, and at least 100 nm.

20. The method of claim 17, wherein, Each of the repeating unit nanostructures has internal features with depths of at least 15 nm, at least 25 nm, at least 50 nm, at least 75 nm, and at least 100 nm.

21. The method according to claim 17, wherein, Each of the repeating unit nanostructures has an outer edge dimension of 100 nm and an internal feature with a cross-sectional dimension of 58 nm and a depth of 55 nm.

22. The method according to claim 16, wherein, The patterning operation includes one of the following: patterning a coating applied to the first primary surface of the waveguide; or directly etching the first primary surface of the waveguide to define nanostructure features.

23. An optical display system, comprising: Light engine; as well as Waveguide, the waveguide comprising: Optical waveguide substrate; The light input region includes a light input diffraction grating integrated in or disposed on the optical waveguide substrate. A light output region, wherein the light output region includes a light output diffraction grating integrated in or disposed on the optical waveguide substrate; and At least one non-diffraction region, the at least one non-diffraction region comprising at least one nanostructured optical non-diffraction array, wherein the at least one nanostructured optical non-diffraction array is integrated in or disposed on the object side of the optical waveguide substrate and at least partially surrounds at least the light output diffraction grating, wherein the external visible reflectance of the at least one nanostructured non-diffraction array is substantially equal to the external visible reflectance of the light output grating.

24. The optical display system according to claim 23, wherein, The optical display system includes a near-eye optical display system.

25. The optical display system according to claim 24, wherein, The near-eye optical display system includes an augmented reality display system.

26. The optical display system according to claim 24, wherein, The near-eye optical display system includes a mixed reality display system.

27. The optical display system according to claim 23, wherein, The optical engine and the waveguide are mounted on the eyeglass frame.

28. The optical display system according to claim 23, wherein, The optical display system includes a head-up display system.

29. A method for modifying the visible reflectivity of a surface of an optical waveguide combiner to obscure the presence of a surface relief grating on the surface, the method comprising: An optical waveguide assembly is provided, the optical waveguide assembly including an optical waveguide substrate, an optical input region, and an optical output region, wherein the optical input region includes an optical input diffraction grating integrated in or disposed on the optical waveguide substrate; and wherein the optical output region includes an optical output diffraction grating integrated in or disposed on the optical waveguide substrate; and Forming at least one non-diffraction region, including: An optical non-diffractive array of at least one nanostructure is disposed or integrated on the object side of the optical waveguide substrate and at least partially around the optical output diffraction grating, wherein the external visible reflectivity of the at least one nanostructure optical non-diffractive array is substantially equal to the external visible reflectivity of the optical output diffraction grating on the object side of the optical waveguide combiner.

30. The method according to claim 29, wherein, The total internal reflection of image-carrying light that can propagate from the light input region to the light output region within the optical waveguide substrate is essentially unaffected by the optical non-diffractive array of the nanostructure.

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