Metasurface-based ar display device and design method and apparatus thereof

Abstract

The embodiment of the application discloses an AR display device based on a super surface and a design method and device thereof. The AR display device based on the super surface comprises a display device, a collimating device, a main lens, a super surface in-coupling light waveguide and a super surface out-coupling light waveguide. The display device is used for loading a virtual scene image. The collimating device is used for making the polychromatic light emitted by the display device vertically incident to the super surface in-coupling light waveguide. The super surface in-coupling light waveguide is used for coupling the light at a plurality of different preset wavelengths in the polychromatic light into the main lens at the same angle through a plurality of different first target diffraction orders. The main lens is used for totally reflecting the light at the plurality of different preset wavelengths. The super surface out-coupling light waveguide is used for coupling the light at the plurality of different preset wavelengths, which is totally reflected by the main lens, out at the same angle through a plurality of different second target diffraction orders. The display effect of the AR display device can be improved by implementing the method of the embodiment of the application.

Description

Technical Field

[0001] This application relates to the field of optical metasurface technology, and in particular to an AR display device based on metasurface and its design method and apparatus. Background Technology

[0002] With the development of technology, 3D display and human-computer interaction are gradually entering people's lives, such as intelligent driving assistance for vehicles, augmented reality (AR) swimming goggles, and virtual reality (VR) motion-sensing games.

[0003] In the field of AR displays, traditional solutions for AR display devices mainly rely on optical waveguide structures with periodic grating designs, including holographic diffractive waveguides, diffractive waveguides, and freeform surface schemes. In these schemes, different wavelengths of light are coupled in and out using the same grating period and first-order diffraction.

[0004] According to the diffraction formula: (Where, d represents the grating period, N represents the diffraction order, and λ represents the wavelength.) As can be seen from the diffraction angle, when the grating period of each wavelength is the same and the diffraction order is 1, the AR display device will have a deviation in the corresponding diffraction angle when coupling in and out light of different wavelengths. This will cause the edge of the AR display device to show color distortion, affecting the display effect of the AR display device. Summary of the Invention

[0005] This application provides an AR display device based on metasurface and its design method and apparatus, which can avoid the color shift at the edge of the eye box caused by different diffraction angles when the AR display device couples in and out with light of different wavelengths, thereby improving the display effect of the AR display device.

[0006] In a first aspect, embodiments of this application provide an AR display device based on a metasurface. The metasurface-based AR display device includes a display device, a collimating device, a main lens, a metasurface-coupled optical waveguide attached to the surface of the main lens, and a metasurface-coupled optical waveguide attached to the surface of the main lens, wherein:

[0007] The display device is used to load virtual scene images;

[0008] The collimation device is used to perpendicularly incident the polychromatic light corresponding to the virtual scene image emitted by the display device onto the metasurface coupled optical waveguide, wherein the polychromatic light includes light at multiple different preset wavelengths;

[0009] The metasurface coupled optical waveguide is used to couple light of multiple different preset wavelengths into the main lens at the same angle through multiple different first target diffraction orders;

[0010] The main lens is used to perform total internal reflection of light at the multiple preset wavelengths;

[0011] The metasurface coupled optical waveguide is used to couple light of multiple different preset wavelengths that have passed through the total internal reflection of the main lens at the same angle through multiple different second target diffraction orders, wherein the first target diffraction order at the same preset wavelength is opposite to the second target diffraction order.

[0012] In some embodiments, the display device is an Lcos, Micro LED, or Mini LED.

[0013] In some embodiments, the metasurface coupled-in waveguide and the metasurface coupled-out waveguide are disposed on a first surface or a second surface of the main lens, wherein the first surface is the side of the main lens closer to the display device, and the second surface is the side of the main lens away from the display device.

[0014] In some embodiments, the main lens is made of glass or resin.

[0015] Secondly, embodiments of this application also provide a design method for an AR display device based on a metasurface, applied to the aforementioned AR display device based on a metasurface in the first aspect, the design method comprising:

[0016] The multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens are obtained, wherein the superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide;

[0017] Based on the preset grating diffraction rules, the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index.

[0018] A first ideal phase distribution is determined based on the plurality of different first target diffraction orders and the target grating period, and a second ideal phase distribution is determined based on the plurality of different second target diffraction orders and the target grating period;

[0019] A first evaluation function is determined based on the first ideal phase distribution, and a second evaluation function is determined based on the second ideal phase distribution;

[0020] The initial metasurface coupled optical waveguide is optimized based on the first evaluation function to obtain the final metasurface coupled optical waveguide, and the initial metasurface coupled optical waveguide is optimized based on the second evaluation function to obtain the final metasurface coupled optical waveguide.

[0021] In some embodiments, the plurality of different preset wavelengths include a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength; the plurality of different first target diffraction orders include red light diffraction orders, green light diffraction orders, and blue light diffraction orders; and the preset grating diffraction rule includes a grating diffraction formula. The determination of the plurality of different first target diffraction orders, the plurality of different second target diffraction orders, and the target grating period based on the preset grating diffraction rule, according to the superatomic period, the plurality of different preset wavelengths, and the refractive index, includes:

[0022] Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is as follows:

[0023] ;

[0024] in, The period of the target grating is, and , It is a positive integer. For the aforementioned superatomic period, The preset red light wavelength, The preset green light wavelength, The preset blue light wavelength, The red light diffraction order is mentioned above. The green light diffraction order is mentioned above. The blue light diffraction order is mentioned above. Let be the coupling angle of the metasurface-coupled optical waveguide, and Where n is the refractive index;

[0025] The plurality of different second target diffraction orders are determined based on the negative numbers of the plurality of different first target diffraction orders.

[0026] In some embodiments, determining the first evaluation function based on the first ideal phase distribution includes:

[0027] The first evaluation function is calculated according to the following formula:

[0028] ;

[0029] in, For the first evaluation function, , representing the number of superatoms within the target grating period. The period of the target grating, Where N is the superatomic period, and N is the number of wavelengths with multiple different preset wavelengths. The position of superatoms and wavelength The first ideal phase distribution under, The position of superatoms and wavelength The actual phase distribution below;

[0030] The second evaluation function is determined based on the second ideal phase distribution, including:

[0031] The first evaluation function is calculated according to the following formula:

[0032] ;

[0033] in, This is the second evaluation function. The position of superatoms and wavelength The second ideal phase distribution below, The position of superatoms and wavelength The actual phase distribution below.

[0034] In some embodiments, optimizing the initial metasurface-coupled optical waveguide based on the first evaluation function to obtain the final metasurface-coupled optical waveguide includes:

[0035] Based on the first evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the first updated structure;

[0036] The first evaluation function is iteratively updated based on the first update structure;

[0037] If the first evaluation function is greater than the first preset threshold and the number of iterations is less than the first preset number of iterations threshold, then continue to update the first update structure to the superatomic size and return to the step of iteratively updating the first evaluation function based on the first update structure;

[0038] If the first evaluation function is less than or equal to the first preset threshold, or the number of iterations is greater than or equal to the first preset number of iterations threshold, then the iterative update is stopped, and the corresponding first update structure is taken as the final metasurface coupled optical waveguide.

[0039] In some embodiments, optimizing the initial metasurface-coupled optical waveguide based on the second evaluation function to obtain the final metasurface-coupled optical waveguide includes:

[0040] Based on the second evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the second updated structure;

[0041] The second evaluation function is iteratively updated based on the second update structure;

[0042] If the second evaluation function is greater than the second preset threshold and the number of iterations is less than the second preset number of iterations threshold, then continue to update the second update structure to the superatomic size and return to the step of iteratively updating the second evaluation function based on the second update structure;

[0043] If the second evaluation function is less than or equal to the second preset threshold, or the number of iterations is greater than or equal to the second preset number of iterations threshold, then the iterative update is stopped, and the corresponding second update structure is taken as the final metasurface coupled optical waveguide.

[0044] Thirdly, embodiments of this application also provide a design apparatus for an AR display device based on a metasurface, comprising:

[0045] The transceiver unit is used to acquire multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens. The superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide.

[0046] The processing unit is configured to, based on a preset grating diffraction rule, determine a plurality of different first target diffraction orders, a plurality of different second target diffraction orders, and a target grating period according to the superatomic period, the plurality of different preset wavelengths, and the refractive index; determine a first ideal phase distribution according to the plurality of different first target diffraction orders and the target grating period, and determine a second ideal phase distribution according to the plurality of different second target diffraction orders and the target grating period; determine a first evaluation function according to the first ideal phase distribution, and determine a second evaluation function according to the second ideal phase distribution; optimize the initial metasurface coupled optical waveguide based on the first evaluation function to obtain a final metasurface coupled optical waveguide, and optimize the initial metasurface coupled optical waveguide based on the second evaluation function to obtain a final metasurface coupled optical waveguide.

[0047] This application provides an AR display device based on metasurfaces and its design method and apparatus. The metasurface-based AR display device includes a display device, a collimating device, a main lens, a metasurface-coupled waveguide attached to the surface of the main lens, and a metasurface-coupled waveguide attached to the surface of the main lens. The display device is used to load a virtual scene image. The collimating device is used to perpendicularly incident polychromatic light corresponding to the virtual scene image emitted by the display device onto the metasurface-coupled waveguide, the polychromatic light including light at multiple different preset wavelengths. The metasurface-coupled waveguide is used to couple the light at multiple different preset wavelengths into the main lens at the same angle through multiple different first target diffraction orders. The main lens is used to perform total internal reflection of the light at multiple different preset wavelengths. The metasurface-coupled waveguide is used to couple the light at multiple different preset wavelengths, after total internal reflection by the main lens, out at the same angle through multiple different second target diffraction orders, wherein the first target diffraction order and the second target diffraction order at the same preset wavelength have opposite values. The metasurface-based AR display device provided in this application has metasurface-coupled waveguides and metasurface-coupled waveguides with different diffraction orders for light of different preset wavelengths. By using different diffraction orders, light of different wavelengths can be coupled in and out at the same angle, thereby avoiding color shift at the edge of the eye box caused by different diffraction angles when the AR display device couples in and out light of different wavelengths, thus improving the display effect of the AR display device. Attached Figure Description

[0048] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0049] Figure 1 This is a schematic diagram of the propagation of polychromatic light in a traditional waveguide.

[0050] Figure 2 A schematic diagram of the structure of an AR display device based on metasurface provided in an embodiment of this application;

[0051] Figure 3 A schematic diagram illustrating the propagation of polychromatic light through a metasurface-coupled optical waveguide provided in an embodiment of this application;

[0052] Figure 4 A flowchart illustrating a design method for an AR display device based on a metasurface, provided in an embodiment of this application;

[0053] Figure 5This is a schematic block diagram of a design apparatus for an AR display device based on a metasurface, provided for an embodiment of this application. Detailed Implementation

[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0055] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0056] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0057] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0058] Please see Figure 1 , Figure 1 This is a schematic diagram of the propagation of polychromatic light in a conventional waveguide. The polychromatic light 10 includes light at different preset wavelengths (11, 12, and 13). Since the conventional waveguide uses the same grating period and first-order diffraction for different wavelengths to achieve the coupling of light in and out, according to the diffraction formula: (Where, d represents the grating period, N represents the diffraction order, and λ represents the wavelength.) As can be seen from the diffraction angle, when the grating period of each wavelength is the same and the diffraction order is 1, the diffraction angle of the traditional AR display device will be deviated when the light of different wavelengths is coupled in and out. This will cause the edge of the AR display device to be color-shifted, affecting the display effect of the AR display device.

[0059] To address the aforementioned issues, this application provides an AR display device based on metasurfaces.

[0060] Please see Figure 2 as well as Figure 3 , Figure 2 This is a schematic diagram of the structure of the AR display device based on metasurface provided in this application. Figure 3 This is a schematic diagram illustrating the propagation of polychromatic light 10 via a metasurface-coupled optical waveguide provided in this application. The metasurface-based AR display device includes a display device 20, a collimating device 30, a main lens 40, a metasurface-coupled optical waveguide 50 attached to the surface of the main lens 40, and a metasurface-coupled optical waveguide 60 attached to the surface of the main lens 40, wherein:

[0061] The display device 20 is used to load virtual scene images. The display device 20 is disposed on the back focal plane of the collimating device 30 to eliminate the light divergence angle and ensure that the light is incident on the main lens 40 / metasurface coupled optical waveguide 50 in a vertical direction.

[0062] The collimation device 30 is used to perpendicularly incident the polychromatic light corresponding to the virtual scene image emitted by the display device 20 onto the metasurface coupled light waveguide 50, wherein the polychromatic light includes light at multiple different preset wavelengths.

[0063] The metasurface coupled optical waveguide 50 is used to couple light of multiple different preset wavelengths into the main lens 40 at the same angle through multiple different first target diffraction orders;

[0064] The main lens 40 is used to perform total internal reflection of light at the multiple preset wavelengths;

[0065] The metasurface coupled optical waveguide 60 is used to couple light of multiple different preset wavelengths that have been totally reflected by the main lens 40 at the same angle through multiple different second target diffraction orders, wherein the first target diffraction order at the same preset wavelength is opposite to the second target diffraction order.

[0066] In this embodiment, the metasurface coupled-in waveguide 50 and the metasurface coupled-out waveguide 60 in the metasurface-based AR display device are configured with different diffraction orders for light of different preset wavelengths. By using different diffraction orders, light of different wavelengths can be coupled out and coupled in at the same angle, thereby avoiding the occurrence of color shift at the edge of the eye box due to different diffraction angles when the AR display device couples in and out light of different wavelengths, thus improving the display effect of the AR display device.

[0067] In some embodiments, the display device 20 is a liquid crystal on silicon (LCOS), a micro light-emitting diode (Micro LED), or a miniature light-emitting diode (Mini LED).

[0068] In some embodiments, the metasurface waveguide 50 and the metasurface waveguide 60 are disposed on a first surface or a second surface of the main lens 40. The first surface is the side of the main lens 40 closest to the display device 20, and the second surface is the side of the main lens 40 furthest from the display device 20. (See also...) Figure 2 , Figure 2 The metasurface coupled-in waveguide 50 and the metasurface coupled-out waveguide 60 described herein are disposed on the second surface of the main lens 40. It can be seen that when the metasurface coupled-in waveguide 50 and the metasurface coupled-out waveguide 60 are disposed on the second surface, light of multiple different preset wavelengths needs to pass through the main lens 40 and then be perpendicularly incident on the metasurface coupled-in waveguide 50 after being collimated by the collimating device 30. If they are disposed on the first surface, light of multiple different preset wavelengths can be directly incident perpendicularly on the metasurface coupled-in waveguide 50 after being collimated by the collimating device 30.

[0069] In some embodiments, the main lens 40 is made of glass or resin. In this embodiment, the selection principle for the material of the main lens 40 is that the higher the refractive index and the higher the light transmission performance, the better. This is because the higher the refractive index, the wider the transmission angle range of the main lens 40, and the higher the light transmission performance, the more realistic the scene perceived by the wearer, which is beneficial to improving the viewing experience.

[0070] Furthermore, the waveguides (metasurface coupled-in waveguide 50 and metasurface coupled-out waveguide 60) in the metasurface-based AR display device provided in this application are directly attached to the surface of the main lens 40, with a thickness of only micrometers (nanopillar structure). Compared with traditional discrete optical components (such as prisms and mirror groups), this greatly reduces the size and weight of optical components in the AR display device, improving the user's comfort when wearing the AR display device.

[0071] like Figure 4As shown, this application embodiment also provides a design method for an AR display device based on a metasurface, applied to the metasurface-based AR display device described above. This application embodiment uses multiple different preset wavelengths, including preset red light wavelength, preset green light wavelength, and preset blue light wavelength, as examples for illustration. This design method mainly describes the design of the metasurface-coupled optical waveguide and the metasurface-coupled optical waveguide in the metasurface-based AR display device. The design method includes: steps S110~S150:

[0072] S110. Obtain the multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens, wherein the superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide.

[0073] In this embodiment, before designing the metasurface coupled-in waveguide and the metasurface coupled-out waveguide, it is necessary to first determine the values ​​of multiple different preset wavelengths in the polychromatic light entering the metasurface coupled-in waveguide and the metasurface coupled-out waveguide.

[0074] In one specific embodiment, a preset red light wavelength is used. 660nm, preset green light wavelength 550nm, preset blue light wavelength It is 437nm.

[0075] Among them, the superatomic period p can be determined according to the structural characteristics of the metasurface. For example, p = 350nm. The refractive index of the main lens is determined by the structural characteristics of the main lens material. The higher the refractive index, the better.

[0076] S120. Based on the preset grating diffraction rules, determine the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period according to the superatomic period, the multiple different preset wavelengths, and the refractive index.

[0077] In some embodiments, the plurality of different preset wavelengths include a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength; the plurality of different first target diffraction orders include red light diffraction orders, green light diffraction orders, and blue light diffraction orders; the preset grating diffraction rule includes a grating diffraction formula; and step S120 includes:

[0078] Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is as follows:

[0079] ;

[0080] in, The period of the target grating is, and , It is a positive integer. For the aforementioned superatomic period, The preset red light wavelength, The preset green light wavelength, The preset blue light wavelength, The red light diffraction order is mentioned above. The green light diffraction order is mentioned above. The blue light diffraction order is mentioned above. Let be the coupling angle of the metasurface-coupled optical waveguide, and Where n is the refractive index;

[0081] The plurality of different second target diffraction orders are determined based on the negative numbers of the plurality of different first target diffraction orders.

[0082] Specifically, the diffraction order and the target grating period for each wavelength are determined, ensuring that the obtained diffraction order and target grating period satisfy the grating diffraction formula while also ensuring that the target grating period is divisible by the atomic period p. Furthermore, the coupling angle of the metasurface-coupled waveguide needs to be greater than [missing value]. .

[0083] In one specific embodiment, after obtaining multiple different first target diffraction orders, taking the negative of each of the multiple different first target diffraction orders yields multiple different second target diffraction orders. For example, the red light diffraction order among the multiple different first target diffraction orders. =+4, Green light diffraction order =+5 and blue light diffraction order =+6; Multiple different second-target diffraction orders also include red, green, and blue diffraction orders, and the red diffraction order is present in multiple different second-target diffraction orders. =-4, Green light diffraction order =-5 and blue light diffraction order =-6.

[0084] In one specific embodiment, the calculated target grating period is 3500nm.

[0085] S130. Determine a first ideal phase distribution based on the plurality of different first target diffraction orders and the target grating period, and determine a second ideal phase distribution based on the plurality of different second target diffraction orders and the target grating period.

[0086] In this embodiment, since the incident and exit angles of light rays in the metasurface coupled-in waveguide and the metasurface coupled-out waveguide are different (opposite), this embodiment requires separate design for the surface coupled-in waveguide and the metasurface coupled-out waveguide. First, the first ideal phase distribution and the second ideal phase distribution are determined respectively.

[0087] Specifically, in this embodiment, the first ideal phase distribution and the second ideal phase distribution can be determined by the multi-order diffraction phase mapping method (a mathematical modeling method based on multi-order diffraction theory, which calculates the ideal phase distribution of the metasurface by setting the wavelength, diffraction order and grating period).

[0088] Specifically, when the phase distribution of the metasurface coupled optical waveguide is in the first ideal phase distribution, the energy of different wavelengths of light in its outgoing light (the light coupled into the main lens) can be mainly concentrated in the corresponding target diffraction order; when the phase distribution of the metasurface coupled optical waveguide is in the second ideal phase distribution, the energy of different wavelengths of light in its outgoing light (the light coupled out into the air (entering the human eye)) can be mainly concentrated in the corresponding target diffraction order.

[0089] S140. Determine a first evaluation function based on the first ideal phase distribution, and determine a second evaluation function based on the second ideal phase distribution.

[0090] Specifically, in some embodiments, the first evaluation function is calculated according to the following formula:

[0091] ;

[0092] in, For the first evaluation function, , representing the number of superatoms within the target grating period. The period of the target grating, Where N is the superatomic period, and N is the number of wavelengths with multiple different preset wavelengths. The position of superatoms and wavelength The first ideal phase distribution under, The position of superatoms and wavelength The actual phase distribution below;

[0093] The second evaluation function is determined based on the second ideal phase distribution, including:

[0094] The first evaluation function is calculated according to the following formula:

[0095] ;

[0096] in, This is the second evaluation function. The position of superatoms and wavelength The second ideal phase distribution below, The position of superatoms and wavelength The actual phase distribution below.

[0097] S150. Based on the first evaluation function, the initial metasurface coupled optical waveguide is optimized to obtain the final metasurface coupled optical waveguide, and based on the second evaluation function, the initial metasurface coupled optical waveguide is optimized to obtain the final metasurface coupled optical waveguide.

[0098] Specifically, in some embodiments, optimizing the initial metasurface-coupled optical waveguide based on the first evaluation function to obtain the final metasurface-coupled optical waveguide includes:

[0099] Based on the first evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the first updated structure;

[0100] The first evaluation function is iteratively updated based on the first update structure;

[0101] If the first evaluation function is greater than the first preset threshold and the number of iterations is less than the first preset number of iterations threshold, then continue to update the first update structure to the superatomic size and return to the step of iteratively updating the first evaluation function based on the first update structure;

[0102] If the first evaluation function is less than or equal to the first preset threshold, or the number of iterations is greater than or equal to the first preset number of iterations threshold, then the iterative update is stopped, and the corresponding first update structure is taken as the final metasurface coupled optical waveguide.

[0103] Specifically, during iteration, particle swarm optimization can be used to make the actual phase distribution match the corresponding first ideal phase distribution as closely as possible.

[0104] Similarly, the optimization of the initial metasurface-coupled optical waveguide based on the second evaluation function to obtain the final metasurface-coupled optical waveguide includes:

[0105] Based on the second evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the second updated structure;

[0106] The second evaluation function is iteratively updated based on the second update structure;

[0107] If the second evaluation function is greater than the second preset threshold and the number of iterations is less than the second preset number of iterations threshold, then continue to update the second update structure to the superatomic size and return to the step of iteratively updating the second evaluation function based on the second update structure;

[0108] If the second evaluation function is less than or equal to the second preset threshold, or the number of iterations is greater than or equal to the second preset number of iterations threshold, then the iterative update is stopped, and the corresponding second update structure is taken as the final metasurface coupled optical waveguide.

[0109] Specifically, during iteration, particle swarm optimization can be used to make the actual phase distribution match the corresponding second ideal phase distribution as closely as possible.

[0110] In this embodiment, the optimized metasurface-coupled waveguide and metasurface-coupled waveguide ensure that when polychromatic light is incident at the same angle, the reflected light angle remains consistent across different wavelengths. This allows different wavelengths of polychromatic light to be coupled out at the same angle after passing through the metasurface-coupled and metasurface-coupled waveguides. This avoids color shift at the edge of the display box caused by different diffraction angles when different wavelengths of light are coupled in and out of the AR display device, thus improving the display effect of the AR display device.

[0111] like Figure 5 As shown in the figure, this application embodiment also provides a design apparatus 500 for an AR display device based on a metasurface, the apparatus 500 comprising:

[0112] The transceiver unit 501 is used to acquire multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens. The superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide.

[0113] Processing unit 502 is configured to, based on preset grating diffraction rules, determine a plurality of different first target diffraction orders, a plurality of different second target diffraction orders, and a target grating period according to the superatomic period, the plurality of different preset wavelengths, and the refractive index; determine a first ideal phase distribution according to the plurality of different first target diffraction orders and the target grating period, and determine a second ideal phase distribution according to the plurality of different second target diffraction orders and the target grating period; determine a first evaluation function according to the first ideal phase distribution, and determine a second evaluation function according to the second ideal phase distribution; optimize the initial metasurface coupled optical waveguide based on the first evaluation function to obtain a final metasurface coupled optical waveguide, and optimize the initial metasurface coupled optical waveguide based on the second evaluation function to obtain a final metasurface coupled optical waveguide.

[0114] In some embodiments, the plurality of different preset wavelengths include a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength; the plurality of different first target diffraction orders include red light diffraction orders, green light diffraction orders, and blue light diffraction orders; and the preset grating diffraction rule includes a grating diffraction formula. When the processing unit executes the step of determining the plurality of different first target diffraction orders, the plurality of different second target diffraction orders, and the target grating period based on the preset grating diffraction rule, according to the superatomic period, the plurality of different preset wavelengths, and the refractive index, it is specifically used for:

[0115] Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is as follows:

[0116] ;

[0117] in, The period of the target grating is, and , It is a positive integer. For the superatomic period, The preset red light wavelength, The preset green light wavelength, The preset blue light wavelength, The red light diffraction order is mentioned above. The green light diffraction order is mentioned above. The blue light diffraction order is mentioned above. Let be the coupling angle of the metasurface-coupled optical waveguide, and Where n is the refractive index;

[0118] The plurality of different second target diffraction orders are determined based on the negative numbers of the plurality of different first target diffraction orders.

[0119] In some embodiments, when the processing unit performs the step of determining the first evaluation function based on the first ideal phase distribution, it is specifically used for:

[0120] The first evaluation function is calculated according to the following formula:

[0121] ;

[0122] in, For the first evaluation function, , representing the number of superatoms within the target grating period. The period of the target grating, Where N is the superatomic period, and N is the number of wavelengths with multiple different preset wavelengths. The position of superatoms and wavelength The first ideal phase distribution under, The position of superatoms and wavelength The actual phase distribution below;

[0123] The second evaluation function is determined based on the second ideal phase distribution, including:

[0124] The first evaluation function is calculated according to the following formula:

[0125] ;

[0126] in, This is the second evaluation function. The position of superatoms and wavelength The second ideal phase distribution below, The position of superatoms and wavelength The actual phase distribution below.

[0127] In some embodiments, when the processing unit performs the step of optimizing the initial metasurface-coupled optical waveguide based on the first evaluation function to obtain the final metasurface-coupled optical waveguide, it is specifically used for:

[0128] Based on the first evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the first updated structure;

[0129] The first evaluation function is iteratively updated based on the first update structure;

[0130] If the first evaluation function is greater than the first preset threshold and the number of iterations is less than the first preset number of iterations threshold, then continue to update the first update structure to the superatomic size and return to the step of iteratively updating the first evaluation function based on the first update structure;

[0131] If the first evaluation function is less than or equal to the first preset threshold, or the number of iterations is greater than or equal to the first preset number of iterations threshold, then the iterative update is stopped, and the corresponding first update structure is taken as the final metasurface coupled optical waveguide.

[0132] In some embodiments, when the processing unit performs the step of optimizing the initial metasurface-coupled optical waveguide based on the second evaluation function to obtain the final metasurface-coupled optical waveguide, it is specifically used for:

[0133] Based on the second evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the second updated structure;

[0134] The second evaluation function is iteratively updated based on the second update structure;

[0135] If the second evaluation function is greater than the second preset threshold and the number of iterations is less than the second preset number of iterations threshold, then continue to update the second update structure to the superatomic size and return to the step of iteratively updating the second evaluation function based on the second update structure;

[0136] If the second evaluation function is less than or equal to the second preset threshold, or the number of iterations is greater than or equal to the second preset number of iterations threshold, then the iterative update is stopped, and the corresponding second update structure is taken as the final metasurface coupled optical waveguide.

[0137] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0138] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. An AR display device based on metasurfaces, characterized in that, The metasurface-based AR display device includes a display device, a collimating device, a main lens, a metasurface-coupled optical waveguide attached to the surface of the main lens, and a metasurface-coupled optical waveguide attached to the surface of the main lens, wherein: The display device is used to load virtual scene images, and the display device is disposed on the back focal plane of the collimation device; The collimation device is used to perpendicularly incident the polychromatic light corresponding to the virtual scene image emitted by the display device onto the metasurface coupled optical waveguide, wherein the polychromatic light includes light at multiple different preset wavelengths; The metasurface coupled optical waveguide is used to couple light of multiple different preset wavelengths into the main lens at the same angle through multiple different first target diffraction orders; The main lens is used to perform total internal reflection of light at the multiple preset wavelengths; The metasurface coupled optical waveguide is used to couple out light at the same angle from the main mirror at the same preset angle through multiple different second target diffraction orders, wherein the first target diffraction order at the same preset wavelength is opposite to the second target diffraction order value. The plurality of different preset wavelengths include preset red light wavelength, preset green light wavelength, and preset blue light wavelength. The first target diffraction order is determined based on the grating diffraction formula, which is: ； Where d is the target grating period, and d = M × p, M is a positive integer, and p is the superatomic period of the metasurface-coupled optical waveguide. The preset red light wavelength, The preset green light wavelength, The preset blue light wavelength, The red light diffraction order is mentioned above. The green light diffraction order is mentioned above. The blue light diffraction order is mentioned above. Let be the coupling angle of the metasurface-coupled optical waveguide, and , where n is the refractive index of the primary lens.

2. The AR display device based on metasurface according to claim 1, characterized in that, The display device is an Icos, Micro LED, or Mini LED.

3. The AR display device based on metasurface according to claim 1, characterized in that, The metasurface coupled-in waveguide and the metasurface coupled-out waveguide are disposed on the first surface or the second surface of the main lens. The first surface is the side of the main lens closer to the display device, and the second surface is the side of the main lens away from the display device.

4. The AR display device based on metasurface according to claim 1, characterized in that, The main lens is made of glass or resin.

5. A design method for an AR display device based on metasurfaces, applied to the AR display device based on metasurfaces as described in any one of claims 1-4, characterized in that, The design method includes: The multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens are obtained, wherein the superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide; Based on the preset grating diffraction rules, the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index. A first ideal phase distribution is determined based on the plurality of different first target diffraction orders and the target grating period, and a second ideal phase distribution is determined based on the plurality of different second target diffraction orders and the target grating period; A first evaluation function is determined based on the first ideal phase distribution, and a second evaluation function is determined based on the second ideal phase distribution; The initial metasurface coupled optical waveguide is optimized based on the first evaluation function to obtain the final metasurface coupled optical waveguide, and the initial metasurface coupled optical waveguide is optimized based on the second evaluation function to obtain the final metasurface coupled optical waveguide.

6. The method according to claim 5, characterized in that, The plurality of different preset wavelengths include preset red light wavelength, preset green light wavelength, and preset blue light wavelength; the plurality of different first target diffraction orders include red light diffraction order, green light diffraction order, and blue light diffraction order; the preset grating diffraction rule includes a grating diffraction formula; the preset grating diffraction rule, based on the superatomic period, the plurality of different preset wavelengths, and the refractive index, determines the plurality of different first target diffraction orders, the plurality of different second target diffraction orders, and the target grating period, including: Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the superatomic period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is as follows: ； Where d is the target grating period, and d = M × p, M is a positive integer, and p is the superatomic period of the metasurface-coupled optical waveguide. The preset red light wavelength, The preset green light wavelength, The preset blue light wavelength, The red light diffraction order is mentioned above. The green light diffraction order is mentioned above. The blue light diffraction order is mentioned above. Let be the coupling angle of the metasurface-coupled optical waveguide, and , where n is the refractive index of the primary lens; The plurality of different second target diffraction orders are determined based on the negative numbers of the plurality of different first target diffraction orders.

7. The method according to claim 5, characterized in that, Determining the first evaluation function based on the first ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ； in, For the first evaluation function, , where d represents the number of superatoms within the target grating period, p represents the superatomic period, and N represents the number of wavelengths with multiple different preset wavelengths. The position of superatoms and wavelength The first ideal phase distribution under, The position of superatoms and wavelength The actual phase distribution below; The second evaluation function is determined based on the second ideal phase distribution, including: The second evaluation function is calculated using the following formula: ； in, This is the second evaluation function. The position of superatoms and wavelength The second ideal phase distribution below, The position of superatoms and wavelength The actual phase distribution below.

8. The method according to claim 5, characterized in that, The optimization process based on the first evaluation function to obtain the final metasurface-coupled optical waveguide includes: Based on the first evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the first updated structure; The first evaluation function is iteratively updated based on the first update structure; If the first evaluation function is greater than the first preset threshold and the number of iterations is less than the first preset number of iterations threshold, then continue to update the first update structure to the superatomic size and return to the step of iteratively updating the first evaluation function based on the first update structure; If the first evaluation function is less than or equal to the first preset threshold, or the number of iterations is greater than or equal to the first preset number of iterations threshold, then the iterative update is stopped, and the corresponding first update structure is taken as the final metasurface coupled optical waveguide.

9. The method according to claim 5, characterized in that, The optimization process based on the second evaluation function to obtain the final metasurface coupled optical waveguide includes: Based on the second evaluation function, the initial metasurface coupled optical waveguide is updated to its superatomic size to obtain the second updated structure; The second evaluation function is iteratively updated based on the second update structure; If the second evaluation function is greater than the second preset threshold and the number of iterations is less than the second preset number of iterations threshold, then continue to update the second update structure to the superatomic size and return to the step of iteratively updating the second evaluation function based on the second update structure; If the second evaluation function is less than or equal to the second preset threshold, or the number of iterations is greater than or equal to the second preset number of iterations threshold, then the iterative update is stopped, and the corresponding second update structure is taken as the final metasurface coupled optical waveguide.

10. A design apparatus for an AR display device based on a metasurface as described in claim 1, characterized in that, include: The transceiver unit is used to acquire multiple different preset wavelengths, superatomic periods, and the refractive index of the main lens. The superatomic period is the superatomic period corresponding to the initial metasurface coupled-in waveguide and the initial metasurface coupled-out waveguide. The processing unit is configured to, based on a preset grating diffraction rule, determine a plurality of different first target diffraction orders, a plurality of different second target diffraction orders, and a target grating period according to the superatomic period, the plurality of different preset wavelengths, and the refractive index; determine a first ideal phase distribution according to the plurality of different first target diffraction orders and the target grating period, and determine a second ideal phase distribution according to the plurality of different second target diffraction orders and the target grating period; determine a first evaluation function according to the first ideal phase distribution, and determine a second evaluation function according to the second ideal phase distribution; optimize the initial metasurface coupled optical waveguide based on the first evaluation function to obtain a final metasurface coupled optical waveguide, and optimize the initial metasurface coupled optical waveguide based on the second evaluation function to obtain a final metasurface coupled optical waveguide.

Images