Metalens array module and display device having the same

Abstract

A metalens array module and a display device are provided, the metalens array module including at least one electronic ink display module (10), at least one optically transparent substrate (42), a plurality of nanostructures (41), and at least one spacer (51). The plurality of nanostructures are arranged on the at least one optically transparent substrate, and the plurality of substructures (41) define one or more metalenses (30) arranged in a predetermined arrangement. The spacer (51) connects the at least one electronic ink display module (10) and the at least one optically transparent substrate (42). The spacer (51) is disposed between the at least one electronic ink display module (10) and the at least one optically transparent substrate (42).

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Patent and Trademark Office (USPTO) patent applications bearing U.S. Provisional Application No. 63 / 439685, filed January 18, 2023; U.S. Provisional Application No. 63 / 454586, filed March 24, 2023; U.S. Provisional Application No. 63 / 470167, filed May 31, 2023; U.S. Provisional Application No. 63 / 533510, filed July 18, 2023; and U.S. Provisional Application No. 18 / 385723, filed October 31, 2023, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present application relates to optical technology, and more particularly to metalens array modules and display devices. [Background technology]

[0003] Hands-free gadgets are gradually replacing older technologies such as mobile phones, tablets, and laptops. Among these gadgets, AR glasses appear to be a suitable replacement. However, these smart glasses have several issues that hinder their real-world applications, including low transparency, short battery life, large volume, eye strain, and discomfort. Furthermore, conventional technologies such as bird bath (or pancake) glasses have very low transparency (less than 20% transparency). While free prisms offer a slight improvement in transparency, they are no match for fully transparent glasses placed in front of the user's eyes. On the other hand, diffractive waveguides offer a further improvement, offering approximately 80% transparency. However, color distortion at the lens edges prevents a fully immersive viewing experience.

[0004] Therefore, the best option is to avoid blocking the user's forward view, allowing the user to see the world without any translucent objects. Furthermore, the lack of optical elements that hold the front space of AR glasses essentially relies on the design flexibility of the optical elements used in the glasses. All of the aforementioned technologies lack design flexibility, primarily due to the inability to remove the optical elements from the front area of ​​the glasses.

[0005] Another approach is to use metalens surfaces, or so-called metalenses, which offer the greatest degree of design freedom. If properly designed, they can be placed anywhere on the AR glasses. However, because 100% transparency is achieved, the metalens can still be seen by the human eye. Furthermore, as the resolution of transparent displays increases, transparency decreases because the electronic devices and pixel address matrix are not completely transparent. Therefore, we speculate that placing metalens or displays around the periphery of the AR glasses frame, so as not to obstruct the user's forward view, could make AR glasses very practical.

[0006] Furthermore, only high-brightness transparent displays (>3000 nits) can be used for outdoor activities, which can easily damage the user's eyes. Therefore, using an extremely bright display is not the ultimate solution. On the other hand, e-ink displays are reflective displays (~40%), do not have a backlight, and can be easily illuminated with a simple LED array. In other words, the light does not directly hit the eyes, and users can feel comfortable looking at e-ink displays within a few hours. Therefore, outdoor activities on bright days are no longer a problem. Most importantly, e-ink displays are very energy-efficient, eliminating the need for frequent daily battery charging. Summary of the Invention [Problem to be solved by the invention]

[0007] The present application provides a metalens array module and a display device. [Means for solving the problem]

[0008] In a first aspect of the present application, a metalens array module is disclosed. The metalens array module includes at least one electronic ink display module, at least one optically transparent substrate, a plurality of nanostructures disposed on the at least one optically transparent substrate, and at least one spacer connecting the at least one electronic ink display module and the at least one optically transparent substrate, wherein the plurality of nanostructures define one or more metalenses arranged in a predetermined array. The at least one spacer is disposed between the at least one electronic ink display module and the at least one optically transparent substrate.

[0009] In one example embodiment of the first aspect, the first aspect discloses a plurality of nanostructures disposed on at least one optically transparent substrate, wherein a plurality of nanojunctions define one or more metalenses, the one or more metalenses being arranged in a predetermined array, and the overlapping metalense array can uniformly distribute light emitted from an electronic ink display module to a user's eye, thereby overcoming the gap between adjacent lenses and metalense edge defects. Furthermore, the metalens array can be applied to a head-mounted display system, thereby solving pixelation issues, realizing a thinner and lighter system, and improving the user experience.

[0010] An embodiment of the first aspect further includes a polarization module disposed between the at least one electronic ink display module and the at least one optically transparent substrate, wherein the at least one spacer is disposed between the polarization module, the at least one optically transparent substrate, and the plurality of nanostructures, and the polarization module is configured to polarize light emitted by the at least one electronic ink display module.

[0011] In one embodiment of the first aspect, the polarizing module further includes an optically transparent gel disposed between the polarizing module and the at least one electronic ink display module, and the polarizing module is pressed against the at least one electronic ink display module via the optically transparent gel.

[0012] One embodiment of the first aspect further includes one or more metalenses arranged in a non-overlapping configuration.

[0013] In one embodiment of the first aspect, the lens further includes one or more metalenses arranged in an overlapping configuration.

[0014] In one embodiment of the first aspect, each of the plurality of nanostructures is isotropically shaped, anisotropically shaped, or a combination of isotropically and anisotropically shaped.

[0015] In one embodiment of the first aspect, the nanostructure further comprises a plurality of nanostructures having the same shape and arranged in different geometric phases.

[0016] In one embodiment of the first aspect, the nanostructure further comprises a plurality of nanostructures having the same shape but different sizes.

[0017] In one embodiment of the first aspect, the nanostructure further comprises a plurality of nanostructures having different shapes and different sizes.

[0018] In one embodiment of the first aspect, the display device further includes at least one light guide disposed between the at least one electronic ink display module, the at least one optically transparent substrate, and the plurality of nanostructures, the at least one light guide configured to uniformly distribute light to the at least one electronic ink display module.

[0019] A second aspect of the present application discloses a display device. The display device includes at least one glass and a metalens array module coupled to the at least one glass. The metalens array module includes at least one electronic ink display module, at least one optically transparent substrate, a plurality of nanostructures disposed on the at least one optically transparent substrate, and at least one spacer connecting the at least one electronic ink display module and the at least one optically transparent substrate. The plurality of nanostructures define one or more metalenses arranged in a predetermined array. The at least one spacer is disposed between the at least one electronic ink display module and the at least one optically transparent substrate.

[0020] In one embodiment of the second aspect, the display device further includes a polarization module disposed between the at least one electronic ink display module and the at least one optically transparent substrate, wherein the at least one spacer is disposed between the polarization module, the at least one optically transparent substrate, and the plurality of nanostructures, and the polarization module is configured to polarize light irradiated by the at least one electronic ink display module.

[0021] In one embodiment of the second aspect, the metalens array module further includes an optically transparent gel disposed between the polarization module and the at least one electronic ink display module, and the polarization module is pressed against the at least one electronic ink display module via the optically transparent gel.

[0022] One embodiment of the second aspect further includes one or more metalenses arranged in a non-overlapping or overlapping configuration.

[0023] In one embodiment of the second aspect, each of the plurality of nanostructures is isotropically shaped, anisotropically shaped, or a combination of isotropically and anisotropically shaped.

[0024] In one embodiment of the second aspect, the nanostructure further comprises a plurality of nanostructures having the same shape and arranged in different geometric phases.

[0025] In one embodiment of the second aspect, the nanostructure further comprises a plurality of nanostructures having the same shape but different sizes.

[0026] In one embodiment of the second aspect, the nanostructure further comprises a plurality of nanostructures having different shapes and different sizes.

[0027] In one embodiment of the second aspect, the display device further includes at least one light guide disposed between the at least one electronic ink display module, the at least one optically transparent substrate, and the plurality of nanostructures, the at least one light guide configured to uniformly distribute light to the at least one electronic ink display module.

[0028] In one embodiment of the second aspect, the display device includes at least one LED disposed around the at least one glass, the at least one LED configured to emit a plurality of light beams along one direction to the at least one electronic ink display module, and the at least one electronic ink display module further configured to reflect the plurality of light beams onto the plurality of nanostructures and the at least one optically transparent substrate.

[0029] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. In the drawings, like reference numerals refer to portions of multiple views. In the drawings, like reference numerals are used throughout corresponding portions of multiple views. [Brief explanation of the drawings]

[0030] [Figure 1A]illustrates at least one embodiment of a display device that transmits or displays AR / VR / MR without a polarization module. [Figure 1B] illustrates at least one embodiment of a display device that uses a polarization module to transmit or display AR / VR / MR. [Figure 2A] ~ [Figure 2D] shows a schematic diagram of the available technologies and their transparency levels. [Figure 3A] ~ [Figure 3C] 1 shows some examples of decentering methods for positioning the display and optical device. [Figure 4A] ~ [Figure 4C] 1 shows some examples of metalens arrays for use in display devices. [Figure 5] shows an example of a metalens that can be produced with different shapes and contours. [Figure 6A] ~ [Figure 6D] 4A-4C show some example unit cells of metalenses in the metalens arrays. [Figure 7A] ~ [Figure 7C] 1A-1D show several examples of display devices including metalens arrays and electronic ink display modules. [Figure 8A] shows an example of the efficiency of three different metasurfaces. [Figure 8B] shows one example of a phase cross section of a metalens. [Figure 8C] shows another example of a phase cross section of a metalens. [Figure 8D] shows another example of a phase cross section of a metalens. [Figure 9] Figure 1 shows a schematic diagram of a combination of a metalens array module and an electronic ink display module for a simple application with an AR / VR / MR device. [Figure 10A] ~ [Figure 10D]1A-1C show some examples of front views of a display device. [Figure 11A] FIG. 1D shows one embodiment of a wedge prism for the light steering application of FIG. [Figure 11B] FIG. 1 shows one example of a free-form wedge prism having a free-form surface. [Figure 12A] ~ [Figure 12D] 1 shows some examples of several types of metalens array modules. [Figure 13A] ~ [Figure 13H] shows several examples of metalens arrays with different collimating, deflecting, and focusing properties. DETAILED DESCRIPTION OF THE INVENTION

[0031] Embodiments of the present disclosure will now be described, by way of example only, with reference to the drawings. The present disclosure is merely exemplary and details may be modified within the principles of the disclosure. It is therefore to be understood that modifications may be made to the embodiments within the scope of the claims.

[0032] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are intended to contribute to a thorough understanding of the embodiments described herein, but should not be considered to limit the scope of the embodiments.

[0033] Here are some definitions that will be used throughout this disclosure.

[0034] The term "coupled" is not necessarily limited to a physical connection, but is defined as connecting directly or indirectly through intermediate components. The term "essentially" is defined to substantially conform to the particular dimensions, shape, or other words to which the term is modified, so that the components do not require precision. The term "comprises," when used, means "including, but not necessarily limited to." Specifically, it expresses open inclusion or membership in any combination, group, series, etc., of these.

[0035] Augmented reality (AR) is a display technology that combines virtual information with the real world. That is, virtual image information projected by an electronic device is integrated based on the real world observed by the human eye. Conventionally, a head-mounted AR display device generally includes an image capture module and a display device for capturing an image within a viewer's field of view and projecting virtual image information based on the captured image at a preset position within the viewer's field of view.

[0036] As shown in FIGS. 1A and 1B, a metalens array module is provided. In the metalens array module, at least one light is emitted from a microdisplay 10, which displays an actual image visible to the viewer's eye. However, depending on the design and the distance between the microdisplays 10A, 10B and the metalens array 30, a real, virtual, or floating image, or a combination thereof, may be formed. The microdisplay 10 and the metalens array 30 are uniformly separated by a spacer 51. At least one light beam consisting of at least one light is limited by an aperture (diaphragm) 8. In the embodiment of FIG. 1A, the polarizing module 20 and the optically transparent gel 50 are not required for the display device 90A. This scheme can also be utilized when using isotropic nanostructures (41), as shown in FIGS. 6A-6D.

[0037] As shown in Figure 1A, the non-polarized display device is used in applications for transmitting or displaying augmented / virtual reality (AR / VR) or mixed reality (MR). A spacer 51 is disposed between the electronic ink display module 10 and the metalens array 30. The microdisplay 10A includes the electronic ink display module 10 in the embodiment of Figure 1A.

[0038] As shown in FIG. 1B , polarizer-dependent display devices are used in applications for conveying or displaying augmented reality (AR) or mixed reality (MR). A spacer 51 is positioned between the polarization module 20 and the metalens array 30. The polarization module 20 may be a linear or circular polarizer. The polarization module 20 is laminated to the electronic ink display module 10 using an optically transparent gel 50. If polarizer-dependent nanostructures are used to fabricate the metalens, the polarization module 20 must be added. In the embodiment of FIG. 1B , the microdisplay 10B includes the electronic ink display module 10, the polarization module 20, and the optically transparent gel 50.

[0039] Figures 2A-2D show schematic diagrams of available technologies and their transparency levels. As shown in Figure 2A, birdbath or pancake lenses used in AR / VR / MR display devices can achieve transparency levels approaching 20%. Figure 2B illustrates a freeform prism used in an AR / VR / MR display device with improved transparency. Figure 2C illustrates a diffractive waveguide method used in an AR / VR / MR display device, which further improves transparency. Finally, Figure 2D illustrates one type of metalens technology used in an AR / VR / MR display device that partially exceeds 100% transparency.

[0040] 3A-3C show some examples of decentering methods for positioning optical and display regions in a display device, such as metalens array 30 or a metalens array module. As shown in FIGS. 3A-3C, optical lenses are located in some types of glasses, such as AR or VR devices. In the optical lenses, at least one visual region is located in a central region of one optical lens.

[0041] FIG. 3A shows a decentering method for placing the optical and viewing region (metalens array 30 or metalens array module) on the left side of the glasses. FIG. 3B shows a decentering method for placing the optical and viewing region (metalens array 30 or metalens array module) at the left corner of one optical lens. FIG. 3C shows a general decentering method for placing the optical and viewing region (metalens array 30 or metalens array module). As shown, the optical and viewing region (metalens array 30 or metalens array module) can be placed anywhere around the viewing region in the form of a single patch, several patches at different locations, or a continuous patch.

[0042] 4A-4C illustrate several examples of metalens arrays 30 for use in display devices such as AR / VR / MR devices. The metalens array 30 represents an optical device including at least one optically transparent substrate 42, a plurality of nanostructures 41, and a cladding layer (in some embodiments, where the unit cell has an impedance-matching cladding layer). The metalens array 30 may be composed of one metalens 35 (single metalens configuration shown in FIG. 4C) or multiple metalenses 35 (metalens array configuration shown in FIG. 4A or FIG. 4B). The multiple nanostructures 41 can be fabricated using electron beam lithography (EBL), deep ultraviolet (DUV) lithography, extreme ultraviolet (EUV) lithography, or nanoimprint lithography (NIL). The master replica in the NIL process can be fabricated using water-soluble polymers such as hard PDMS (h-PMDS) or polyvinyl alcohol (PVA), but is not limited to these techniques. As shown in FIG. 4A, four metalenses 35 are provided on at least one optically transparent substrate 42. The number of metalenses 35 is not limited in the present disclosure. As shown in FIGS. 4A-4C , a plurality of nanostructures 41 are disposed on at least one optically transparent substrate 42 to form one or more metal lenses 35. In one embodiment, the at least one optically transparent substrate 42 may be any type of transparent substrate, such as glass made of fused silica (SiO 2 ) or sapphire. The plurality of nanostructures 41 are designed and fabricated on the surface of the at least one optically transparent substrate 42 to form one or more metalenses 35. The zoom region 40 is the magnified region of each metalens 35. In some embodiments, the plurality of nanostructures 41 may be arranged in any desired array, such as a mesh array, a row array, a column array, or an array of any shape. In some embodiments, the plurality of nanostructures 41 can be made from passive materials such as dielectrics, such as TiO2, GaN, GaP, SiN, Si, Nb2O5, SiO2, Al2O3, HfO2, Poly-Si, curable resins, photoresists, metal oxide nanoparticles, and sol-gel mixtures of gold (Au), silver (Ag), and aluminum (Al).In another embodiment, the plurality of nanostructures 41 can be made from, or a combination of, phase change materials (GST (GeSbTe), vanadium dioxide (VO), gallium (Ga), metallopolymers), and 2D materials (graphene, hBN, WS). Note that the thickness of the nanocolumns can vary from 50 nanometers to several thousand nanometers, but is not limited to these ranges. As shown in FIG. 4A , the metalenses 35 of the metalens array 30 are arranged so that they do not overlap one another.

[0043] As shown in FIG. 4B , the metalens array 30 includes a plurality of metalenses 35 and at least one optically transparent substrate 42. As shown, the metalenses 35 of the metalens array 30 are arranged so as to overlap one another on the at least one optically transparent substrate 42. The at least one optically transparent substrate 42 may be any type of transparent substrate, such as glass made of fused silica (SiO 2 ) or sapphire. As shown in FIG. 4B , one or more metalenses 35 of the metalens array 30 are formed by designing and fabricating a plurality of nanostructures 41 on the surface of the at least one optically transparent substrate 42. The number of metalenses 35 is not limited by the present application. The plurality of nanostructures 41 define a plurality of metalens arrays 30. The plurality of metalens arrays 30 can be arranged in any desired arrangement, such as a grid array, a row array, a column array, or an array of any shape. The passive nanostructures 41 are made of dielectric materials such as TiO2, GaN, GaP, SiN, Si, Nb2O5, SiO2, Al2O3, HfO2, Poly-Si, curable resins, photoresists, metal oxide nanoparticles, sol-gel mixtures, etc. The active nanostructures 41 are made of phase change materials (GST (Ge2Sb2Te5), vanadium dioxide (VO2), gallium (Ga), metal polymers), and 2D materials (graphene, hBN, WS2) or combinations of these materials, with nanocolumn thicknesses ranging from, but not limited to, 100 nanometers to several thousand nanometers.

[0044] As shown in FIG. 4B, each metalens 35 in the metalens array 30 is arranged so as to overlap another metalens 35.

[0045] As shown in FIG. 4C , the metalens array 30 includes a single metalens 35 and at least one optically transparent substrate 42. The at least one optically transparent substrate 42 may be any type of transparent substrate, such as glass made of fused silica (SiO ) or sapphire. To form the single metalens 35 of the metalens array 30, a plurality of nanostructures 41 are designed and fabricated on the surface of the at least one optically transparent substrate 42. The zoom region 40 is a magnified region of the single metalens 35. The plurality of nanostructures 41 can be arranged in any desired array, such as a grid array, a row array, a column array, or an array of any shape. The plurality of passive nanostructures 41 are fabricated from a dielectric material, such as TiO , GaN, GaP, SiN, Si, Nb O , SiO , Al O , HfO , Poly-Si, a curable resin, a photoresist, metal oxide nanoparticles, or a sol-gel mixture. Additionally, the active nanostructures 41 are made of phase change materials (GST (Ge2Sb2Te5), vanadium dioxide (VO2), gallium (Ga), metal polymers), and 2D materials (graphene, hBN, WS2) or are formed by combining these materials, and the thickness of the nanocolumns varies from 100 nanometers to several thousand nanometers, but is not limited to these ranges.

[0046] In at least one embodiment of the present application, a metalens array module includes at least one electronic ink display module 10 as shown in FIGS. 1A and 1B , a metalens array 30 including at least one optically transparent substrate 42 and a plurality of nanostructures 41 as shown in FIGS. 4A-4C , and at least one spacer 51 as shown in FIGS. 1A and 1B . In the metalens array 30, a plurality of nanostructures 41 are disposed on the at least one optically transparent substrate 42, and the plurality of nanostructures 41 define one or more metalenses 35, and the one or more metalenses 35 are arranged in a predetermined arrangement. For example, as shown in FIG. 4A , the one or more metalenses 35 may be arranged in a non-overlapping configuration, as shown in FIG. 4B , or in an overlapping configuration, as shown in FIG. 4C , or the plurality of nanostructures 41 define a single metalens. The at least one spacer 51 connects the at least one electronic ink display module 10 and the at least one optically transparent substrate 42. At least one spacer 51 is disposed between the at least one electric ink display module 10 and the at least one optically transparent substrate 42. The at least one electric ink display module 10 is configured to irradiate light onto the plurality of nanostructures 41 and the at least one optically transparent substrate 42.

[0047] In at least one embodiment of the present application, the metalens array module may further include a polarization module 20 as shown in FIG. 1B . The polarization module 20 is disposed between the at least one electronic ink display module 10 and the at least one metalens array 30. The aforementioned spacer 51 is located between the polarization module 20 and the metalens array 30 (the metalens array 30 includes at least one optically transparent substrate 42 and a plurality of nanostructures 41). The polarization module 20 is configured to polarize light emitted by the at least one electronic ink display module 10.

[0048] In at least one embodiment, the metalens array module further includes an optically transparent gel 50 as shown in FIG. 1B. The optically transparent gel 50 is disposed between the polarization module 20 and the at least one electronic ink display module 10. The polarization module 20 is laminated to the at least one electronic ink display module 10 via the optically transparent gel 50.

[0049] FIG. 5 shows an example of a metalens 35 produced with different shapes and contours, including a plurality of isotropic, anisotropic, or a combination of isotropic and anisotropic nanostructures 41. Metalenses 35 produced with different shapes can be used in the disclosed structures shown herein. A plurality of nanostructures 41 and at least one optically transparent substrate 42 can produce metalens 35 with different shapes. Metalens 35 can have different shapes, any shape, as shown in FIG. 5. Metalenses 35 with different or the same shape and at least one optically transparent substrate 42 form a metalens array 30.

[0050] In at least one embodiment, each of the plurality of nanostructures 41 may be an isotropic shape, an anisotropic shape, or a combination of isotropic and anisotropic shapes, as shown in FIG. 5. For example, an isotropic shape may be circular, square, or have the same size when viewed from either side. For example, an anisotropic shape may be rectangular, "L"-shaped, "H"-shaped, or any shape with different dimensions when viewed from different sides. In other embodiments, each of the plurality of nanostructures 41 may be other shapes, such as rectangular or "H"-shaped, without being limited to the present disclosure.

[0051] FIG. 6A shows an example of a rectangular (or any anisotropic shaped) unit cell of a metalens 35 having nanostructures 41 with dimensions of width W, length L, and height H, and at least one optically transparent substrate 42 with dimensions of pitch Px (in the x-direction) and pitch Py (in the y-direction). In this disclosure, a metalens array 30 refers to an optical device including at least one optically transparent substrate 42 and nanostructures 41. A metalens array 30 may be composed of one metalens 35 (single metalens configuration) or multiple metalenses 35 (metalens array configuration). Each metalens 35 is composed of multiple unit cells. For example, each metalens 35 may be composed of one million unit cells. If the metalens 35 is composed of anisotropic nanostructures 41, a polarization module would need to be added to the metalens array 30.

[0052] 6B shows one example of a rectangular unit cell of metalens 35. The rectangular unit cell of metalens 35 includes nanostructures 41 having dimensions of width W, length L, and height H; a cladding layer 43 having a thickness T and being an impedance matching material that matches the refractive index of the substrate, similar to a photoresist etchant; and at least one optically transparent substrate 42 having dimensions of pitch Px (along the x-direction) and pitch Py (along the y-direction). The refractive index of the cladding layer 43 can approach the refractive index of the at least one optically transparent substrate 42. The cladding layer 43 can be spin-coated (or otherwise deposited) onto the at least one optically transparent substrate 42. The cladding layer 43 can be formed from SiO, resin, photoetch resist, etc.

[0053] 6C shows an example of a cylindrical (or any isotropic shaped) unit cell of a metalens 35 that includes nanostructures 41 having dimensions of diameter D and height H, and at least one optically transparent substrate 42 having dimensions of pitch Px (along the x-direction) and pitch Py (along the y-direction). If metalens 35 is made of isotropic nanostructures 41, then no additional polarization modules are required in the metalens array 30.

[0054] FIG. 6D shows an example of a cylindrical unit cell of a metalens 35 including nanostructures 41 having a diameter D and a height H, a cladding layer 43 having a thickness T and being an impedance matching material that matches the refractive index of the substrate, similar to a photoresist etchant, and at least one optically transparent substrate 42 having dimensions of a pitch Px (along the x-direction) and a pitch Py (along the y-direction). The refractive index of the cladding layer 43 can be close to the refractive index of the at least one optically transparent substrate 42. The impedance matching material can increase the efficiency of the metalens and protect the nanostructures. The cladding layer 43 can be spin-coated (or otherwise deposited) onto the at least one optically transparent substrate 42. The cladding layer 43 can be formed from SiO, resin, photoresist etch, etc. Note that a combination of isotropic and anisotropic nanostructures 41 is also possible.

[0055] In at least one embodiment, Figures 6A-6D illustrate at least one cell of a passive metalens of the metalens array 30 of Figures 4A-4C. There may be multiple unit cells forming a metalens (e.g., one metalens 35 or multiple metalenses 35 as shown in Figures 4A-4C). There may also be multiple metalenses 35 forming the metalens array 30 (e.g., one or more metalenses 35 forming the metalens array 30 as shown in Figures 4A-4C). Alternatively, the metalens array 30 may be formed by arranging multiple metalenses 35. Furthermore, each metalens 35 may be formed by arranging multiple unit cells.

[0056] In some embodiments, the unit cells of metalens array 30 can have the same size or different sizes. For example, three or more different unit cells can be used because each color has a different spacing, width, and length, but the same height is required for all colors. However, in some particular embodiments, the same unit cells (same spacing) can be used for all colors (having different widths and lengths, but the same height).

[0057] In at least one embodiment, the plurality of nanostructures 41 may have various shapes and arrangements. For example, in one embodiment, the plurality of nanostructures 41 have the same shape and are arranged in different geometric topologies. In another embodiment, the plurality of nanostructures 41 have the same shape but different dimensions. In another embodiment, the plurality of nanostructures 41 have different shapes and different sizes.

[0058] As shown in Figures 7A-7C, only high-brightness transparent displays (>3000 nits) can be used for outdoor activities with transparent glasses (such as AR glasses), which can easily damage the user's eyes. Therefore, using an extremely bright display is not the ultimate solution. On the other hand, e-ink displays are reflective displays (~40%), lack backlighting, and can be easily illuminated with a simple LED array. In other words, reflected light does not shine directly into the eyes, ensuring that users feel comfortable while viewing e-ink displays within a few hours. Therefore, outdoor activities on bright days are no longer a problem. Most importantly, e-ink displays are very energy-efficient, eliminating the need for frequent daily battery charging.

[0059] In one embodiment, FIG. 7A shows an example of a metalens array 30 and an electronic ink display module 10 applied to an optical or display device such as an AR / VR / MR device (not shown in FIGS. 7A-7C ). As shown in FIG. 7A , the metalens array module (optical or display device) includes at least one spacer 51 disposed between the electronic ink display module 10 and the metalens array 30. In one embodiment, the electronic ink display module 10 may be any type of electronic ink display without LEDs attached, such as a monochrome, multicolor, or full-color electronic ink display. The metalens array module (optical or display device) shown in FIG. 7A may be integrated into eyeglasses or designed in the form of a clamping device that can be attached to (hang on) typical eyeglasses.

[0060] As shown in Figure 7A, some light can reach the electronic ink display module 10 through at least one spacer 51. The ambient light is reflected by the electronic ink display module 10. The light is then redirected by the metalens array 30. The light reflected by the electronic ink display module 10 is visible to the eye.

[0061] FIG. 7B shows another embodiment of a metalens array module (optical device or display device) including a metalens array 30 and an electronic ink display module 10. The metalens array module (optical device or display device) includes at least one spacer 51 disposed between the electronic ink display module 10 and the metalens array 30. Furthermore, the metalens array module (optical device) includes at least one LED 13 positioned around the eyeglass frame, elbow, or bridge of the eyeglasses. In one embodiment, at least one LED 13 is used, or multiple LEDs 13 can be used. The backlight LEDs can have different colors and tuning, such as from warm to cool temperatures. One or more LEDs can be positioned in different locations. In one embodiment, the electronic ink display module 10 can be any type of electronic ink display, such as a monochromatic, multicolor, or full-color display. The optical device or display device shown in FIG. 7B can be integrated into eyeglasses or designed in the form of a clamping device that can be attached (hang) on ​​typical eyeglasses. 7B , the at least one LED 13 emits multiple light beams toward the E-ink display module 10, and the multiple light beams are reflected by the E-ink display module 10. The E-ink display module 10 then redirects the multiple light beams toward the metalens array 30. The user's eyes see the multiple light beams reflected by the E-ink display module 10.

[0062] FIG. 7C shows another embodiment of a metalens array module (optical device or display device) using a metalens array 30, a light guide 11, and an electronic ink display module 10. As shown in FIG. 7C, the metalens array module (optical device or display device) includes at least one spacer 51 disposed between the light guide 11 and the metalens array 30. The optical device further includes an encapsulant 553 having a lower refractive index than the light guide to prevent light from being reflected by total internal reflection (TIR) ​​within the light guide. The encapsulant 553 may be an encapsulant paste or may be replaced by air. The light guide 11 is located between the electronic ink display module 10 and the metalens array 30. As shown in FIG. 7C, the output couplers of the light guide 11 may have a uniform spacing (d1 = d2 = dn) or may have different spacings (d1 ≠ d2 ≠ dn). At least one LED 13 and a spacer 51 are disposed between the electronic ink display module 10 and the metalens array 30. In one embodiment, at least one or more LEDs 13 are disposed on the opposite side of the light guide 11. The light guide 11 uniformly distributes light from the at least one LED 13 or multiple LEDs 13 to the electronic ink display module 10. The backlight LEDs can have different colors and tunings, such as from warm to cool temperatures. The single LED 13 or multiple LEDs 13 can be disposed in different positions. In one embodiment, the electronic ink display module 10 can be any type of electronic ink display, such as a monochromatic, multicolor, or full-color display. The electronic ink display can be used in the display module shown in FIG. 1A or FIG. 1B. The optical device shown in FIGS. 7A-7C can be integrated into eyeglasses or designed in the form of a clamping device that can be attached (hanged) on typical eyeglasses.

[0063] In at least one embodiment, the metalens array module further includes at least one light guide 11, as shown in FIG. 7C , disposed between the at least one electronic ink display module 10, the at least one optically transparent substrate 42, and the plurality of nanostructures 41. The at least one light guide is configured to uniformly distribute light to the at least one electronic ink display module 10.

[0064] FIG. 8A shows the efficiency of three different TiO metasurfaces of metalens 30 over the blue, green, and red spectra.

[0065] Figure 8B shows the phase distribution of a 300 μm diameter metalens with a polar incidence angle θ = 0° and an azimuthal angle φ = 0°. In Equation 1, θ is the coaxial or off-axis focus angle, and φ is the azimuthal angle. This design is similar to the prior art shown in Figure 2D, which affects the front view of the user.

[0066] Figure 8C shows the phase distribution of a 300 μm diameter metalens with a polar incident angle θ = 10° and an azimuthal angle φ = 90°, where θ is the on-axis or off-axis focus angle and φ is the azimuthal angle, as shown in Equation 1.

[0067] Figure 8D shows the phase distribution of a 300 μm diameter metalens with a polar incident angle θ = 10° and an azimuthal angle φ = 45°, where θ is the on-axis or off-axis focus angle and φ is the azimuthal angle, as shown in Equation 1.

[0068] The phase retardation of a metalens can be written in different forms, for example one common formula is: TIFF2026505950000002.tif41140

[0069] where f is the focal length of the metalens, r is the distance of each nanostructure relative to the center of the metalens, θi is the coaxial or off-axis focus angle, i is the index of the operating wavelength, Φ is the azimuthal angle, φc(r,λi) is the off-axis aberration compensation phase term, C(λi) is the steady-state phase for further phase adjustment, which can be optimized by a particle swarm optimization (PSO) algorithm, and α is the quasi-orthogonal angle, as shown in Equation 2.

[0070] 9 shows a schematic diagram of a proposed metalens array module 300 for a simple application using an AR / VR / MR device. Each metalens array module 300 can be placed in a different position on the AR / VR / MR device and in combination with different glasses. As shown, each metalens array module 300 displays different information.

[0071] FIG. 10A shows an example of a front view of an optical or display device, such as a metalens array module 300, applied to an AR / VR / MR device. As shown in FIG. 10A , a glass module 8R is used in the AR / VR / MR device. The glass module 8R shows at least one metalens array module 300 (including an electronic ink display module 10) coupled to a transparent glass zone. Ambient light reaches the eye through the transparent glass zone, and light generated or reflected by the electronic ink display module 10 is transmitted directly toward the eye.

[0072] FIG. 10B shows another example of a glass module 8R including at least one optical device, applying the metal array module 300 shown in FIGS. 7A-7C to the presented AR / VR / MR glasses. This method is effective when the metal lens is not significantly offset from the center of the glasses. The displayed content is transmitted through a metalens (any of those shown herein) with a uniform deflection angle of α1 and deflected toward the user's eye.

[0073] FIG. 10C shows another embodiment of a glass module 8R. The glass module 8R includes at least one optical device shown in FIGS. 7A-7C among the presented AR / VR / MR devices. This method is effective when the metalens is located at the corner of the glasses, away from the center of the glasses. The displayed content is transmitted and deflected to the user's eye through an installed double or double-layer metalens set with a uniform deflection angle α2, where α2 > α1. The two-layer-based metal optical element may face or not face the electronic ink display on two surfaces of a single substrate or on one surface of two separate substrates. For more details, see FIGS. 12B-12D.

[0074] FIG. 10D shows a glass module 8R with a wedge prism added, using a metalens array module 300 in one of the AR / VR / MR devices. This design requires only one metalens array 30. Also, if the display area is large and needs to be focused toward the user's eye, the wedge prism can be refracted as shown in FIG. 11A or as shown in FIG. 11B. The displayed content is transmitted to and deflected toward the user's eye by a single metalens array 30 (as shown in any of FIGS. 4A-4C) or a doublet / doublet layer metalens set (as shown in any of FIGS. 12A-12D) at non-uniform deflection angles α3, α4, and α5. The optical wedge not only helps to set the additional deflection angle of the metalens, but is also used to correct optical aberrations and wavefronts of the light beam from the metalens set.

[0075] Figure 11A shows an example of a wedge prism for light steering applications in Figure 10D. The wedge prism is made of any transparent material, such as glass, acrylic, and fluorite. ψ is the angle between the prism surfaces, α is the unrefracted angle, β is the refracted angle, and γ is the exit angle of the wedge prism.

[0076] FIG. 11B shows an example of a freeform wedge prism with a freeform surface to correct aberrations and distortions caused by the metalens before the light beam reaches the user's eye, such as the parabolic surface of FIG. 10D for light steering applications. For large monitors, it is necessary to converge the light to a focal point. The wedge prism can be made from transparent materials such as glass, acrylic, and fluorite. α is the unrefracted angle, β is the refracted angle, and γ is the exit angle of the freeform wedge prism.

[0077] In one embodiment, FIG. 12A details one type of single-layer metalens array 411 applied to an optical device. The nanostructures 41 face the electronic ink display module 10. As shown in FIG. 12A , one single-layer metalens array 411 is composed of nanostructures 41, and the single-layer metalens array 411 is disposed on at least one optically transparent substrate 42. A spacer 51 is disposed between the electronic ink display module 10 and the at least one optically transparent substrate 42. The eye sees light that is emitted or reflected from the electronic ink display module 10 and transmitted to the metalens array 411 and the at least one optically transparent substrate 42. The nanostructures 41 can face the electronic ink display module 10 (as shown in FIG. 12A ) or the user's eye (as shown in FIG. 10B ).

[0078] As shown in FIG. 12B , two-layer metalens arrays 412 and 413 are made of nanostructures 41. The two-layer metalens arrays 412 and 413 are disposed on two opposite sides of at least one optically transparent substrate 42. One of the two metalens layers is the upper layer of the metalens array 412, and the other is the lower layer of the metalens array 413. As shown, a spacer 51 is positioned between the electronic ink display module 10 and the at least one optically transparent substrate 42. A spacer 512 is positioned between the at least one optically transparent substrate 42 and a transparent protective film / substrate 422. The upper metalens array 412 represents a metalens nanostructure, and the lower metalens array 413 represents a deflecting metasurface or metalens nanostructure. A user's eye sees light emitted or reflected from the electronic ink display module 10 and transmitted to the metalens arrays 412 and 413, the substrate 42, and the transparent protective film / substrate 422. In some embodiments, the at least one optically transparent substrate 42 can be any type of flexible transparent material, such as a water-soluble polymer such as polyvinyl alcohol (PVA). The transparent protective film / substrate 422 can be any type of solid transparent film or glass, or any type of flexible transparent material that is a water-soluble polymer such as polyvinyl alcohol (PVA).

[0079] FIG. 12C is a detailed diagram of another type of optical device shown in FIG. 10C . When using two metalens arrays 412, 414 or one metalens array 412 and one deflecting metasurface 414, as shown in FIG. 12C , the two metalens arrays 412, 414 are disposed on the same side of at least one optically transparent substrate 42 and a transparent protective film / substrate 422. One of the two metalens layers is the top layer of the metalens array 412, and the other is the second top layer of the metalens array 414. The second top layer of the metalens array 414 is a deflecting metasurface or metalens. As shown in FIG. 12D , a spacer 51 is positioned between the electronic ink display module 10 and the at least one optically transparent substrate 42. A spacer 52 is positioned between the at least one optically transparent substrate 42 and the transparent protective film / substrate 422. A user's eye sees light emitted or reflected from electronic ink display module 10 and transmitted to metalens arrays 412, 414, substrate 42, and transparent protective film / substrate 422. In some embodiments, at least one optically transparent substrate 42 can be any type of flexible transparent material, such as a water-soluble polymer such as polyvinyl alcohol (PVA). Transparent protective film / substrate 422 can be any type of flexible transparent material, such as any type of solid transparent film or glass, or a water-soluble polymer such as polyvinyl alcohol (PVA).

[0080] FIG. 12D shows another type of optical device using two metalens arrays 413, 414, or one metalens array 413 and one deflecting metasurface array 414. The two metalens arrays 413, 414 are disposed on different sides of at least one optically transparent substrate 42 and a transparent protective film / substrate 422. One of the two metalens layers is a bottom layer of the metalens array 413 disposed on the at least one optically transparent substrate 42, and the other is a second, upper layer of the metalens array 414 disposed on the transparent protective film / substrate 422. The second upper layer of the metalens array 414 is a deflecting metasurface or metalens. As shown in FIG. 12D, a spacer 51 is positioned between the electronic ink display module 10 and the at least one optically transparent substrate 42. A spacer 52 is positioned between the at least one optically transparent substrate 42 and the transparent protective film / substrate 422. A user's eye sees light emitted or reflected from electronic ink display module 10 and transmitted to metalens arrays 413, 414, substrate 42, and transparent protective film / substrate 422. In some embodiments, at least one optically transparent substrate 42 can be any type of flexible transparent material, including, for example, a water-soluble polymer such as polyvinyl alcohol (PVA). Transparent protective film / substrate 422 can be any type of solid transparent film or glass, or any type of flexible transparent material that is a water-soluble polymer such as polyvinyl alcohol (PVA).

[0081] In at least one embodiment, a display or optical device includes at least one glass and a metalens array module. The metalens array module is coupled with the at least one glass, as shown in FIGS. 10A-10C. The metalens array 30 of the metalens array module 300 can be any metalens array 30 or combinations thereof, as shown in FIGS. 4A-4C, 7A-7C, and 12A-12D.

[0082] In at least one embodiment, the display device or optical device further includes at least one LED 13, as shown in Figure 7B. The at least one LED 13 is located around the at least one glass. The at least one LED 13 is configured to emit a plurality of light beams toward the at least one E-ink display module 10. The at least one E-ink display module 10 is further configured to reflect the plurality of beams onto the plurality of nanostructures 41 and the at least one optically transparent substrate 42.

[0083] FIGS. 13A-13H show several examples of metalens arrays with different collimating, deflecting, and focusing characteristics. Multiple overlapping metalens arrays or metalens arrays 71, 72, 73, 74, 75, and 76 may be one of those shown in FIGS. 12A-12D. Whether an electronic ink display module 10 has a polarization module or not depends on the type of metalens array (isotropic or anisotropic). FIGS. 13A, 13E, 13G, and 13H are coaxial designs, while the rest are off-axis schemes. The output light emitted from the electronic ink display module 10 and passing through the metalens arrays 71-76 can be collimated, tilted, diverged, or converged. When using a large electronic ink display module 10 and a proportionally large overlapping metalens array 72, as is preferred in FIG. 13B, the light beam must be focused toward the user's eye; otherwise, the user will not be able to see part of the display content. 13C, 13D, and 13F may be used when the electronic ink display module 10 is vertically displaced to enhance the visibility of ambient light. Figures 13E, 13G, and 13H are coaxial schematic diagrams with various refractive indices.

[0084] Although the present disclosure has been described with reference to specific embodiments, these embodiments should not be construed as limiting the present disclosure. Accordingly, those skilled in the art may make various modifications to the above-described embodiments without departing from the scope of the appended claims.

Claims

1. 1. A metalens array module, comprising: at least one electronic ink display module; at least one optically transparent substrate; a plurality of nanostructures disposed on the at least one optically transparent substrate; and at least one spacer connecting the at least one electronic ink display module and the at least one optically transparent substrate; the plurality of nanostructures define one or more metalenses arranged in a predetermined array; 10. The metalens array module of claim 9, wherein the at least one spacer is disposed between the at least one electronic ink display module and the at least one optically transparent substrate.

2. the metalens array module further includes a polarization module; the polarization module is disposed between the at least one electronic ink display module and the at least one optically transparent substrate; the at least one spacer is disposed between the polarization module and the at least one optically transparent substrate and the plurality of nanostructures; 10. The metalens array module of claim 1, wherein the polarization module is configured to polarize light emitted by the at least one electronic ink display module.

3. The polarizing module further includes an optically transparent gel disposed between the polarizing module and the at least one electronic ink display module; 3. The metalens array module of claim 2, wherein the polarization module is pressed onto the at least one electronic ink display module via the optically transparent gel.

4. 10. The metalens array module of claim 1, wherein the one or more metalenses are arranged in a non-overlapping configuration.

5. 10. The metalens array module of claim 1, wherein the one or more metalenses are arranged in an overlapping configuration.

6. 6. The metalens array module of claim 5, wherein each of the plurality of nanostructures has an isotropic shape, an anisotropic shape, or a combination of an isotropic and anisotropic shape.

7. 10. The metalens array module of claim 1, wherein the plurality of nanostructures have the same shape and are arranged in different geometric phases.

8. 10. The metalens array module of claim 1, wherein the plurality of nanostructures have the same shape but different sizes.

9. 10. The metalens array module of claim 1, wherein the plurality of nanostructures have different shapes and different sizes.

10. further comprising at least one light guide; the at least one light guide is disposed between the at least one electronic ink display module, the at least one optically transparent substrate, and the plurality of nanostructures; 10. The metalens array module of claim 1, wherein the at least one light guide is configured to uniformly distribute light to the at least one electronic ink display module.

11. A display device, at least one glass; and a metalens array module coupled to the at least one glass; The metalens array module comprises: at least one electronic ink display module; at least one optically transparent substrate; a plurality of nanostructures disposed on the at least one optically transparent substrate; at least one spacer connecting the at least one electronic ink display module and the at least one optically transparent substrate; the plurality of nanostructures define one or more metalenses, the one or more metalenses being arranged in a predetermined array; 10. A display device, comprising: at least one spacer disposed between the at least one electronic ink display module and the at least one optically transparent substrate.

12. further comprising a polarization module disposed between the at least one electronic ink display module and the at least one optically transparent substrate; the at least one spacer is disposed between the polarization module and the at least one optically transparent substrate and the plurality of nanostructures; 12. The display device of claim 11, wherein the polarization module is configured to polarize light emitted by the at least one electronic ink display module.

13. the metalens array module further comprises an optically transparent gel, the optically transparent gel being disposed between the polarization module and the at least one electronic ink display module; and 13. The display device of claim 12, wherein the polarizing module is pressed onto the at least one electro-ink display module via the optically transparent gel.

14. 12. The display device of claim 11 , wherein the one or more metalenses are arranged in a non-overlapping or an overlapping configuration.

15. 15. The display device of claim 14, wherein each of the plurality of nanostructures has an isotropic shape, an anisotropic shape, or a combination of an isotropic and anisotropic shape.

16. 12. The display device of claim 11, wherein the plurality of nanostructures have the same shape and are arranged in different geometric phases.

17. 12. The display device of claim 11, wherein the nanostructures have the same shape but different sizes.

18. The display device of claim 11 , wherein the plurality of nanostructures have different shapes and different sizes.

19. the metalens array module further comprises at least one light guide; the at least one light guide is disposed between the at least one electronic ink display module and the at least one optically transparent substrate and the plurality of nanostructures; 12. The display device of claim 11, wherein the at least one light guide is configured to distribute light evenly to the at least one electronic ink display module.

20. at least one LED disposed around the at least one glass; the at least one LED is configured to emit a plurality of light beams along one direction to the at least one electronic ink display module; 12. The display device of claim 11, wherein the at least one electronic ink display module is further configured to reflect a plurality of light beams onto the plurality of nanostructures and the at least one optically transparent substrate.

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