AR (Augmented Reality) display equipment based on metasurface and design method and device thereof

Abstract

The embodiment of the invention discloses AR (Augmented Reality) display equipment based on a metasurface and a design method and device thereof. The AR display device based on the metasurface comprises a display device, a collimating device, a main lens, a metasurface coupling-in optical waveguide and a metasurface coupling-out optical waveguide, and the display device is used for loading a virtual scene image; the collimating device is used for enabling polychromatic light emitted by the display device to vertically enter the metasurface to be coupled into the optical waveguide; the metasurface coupling-in optical waveguide is used for coupling light under multiple different preset wavelengths in the polychromatic light into the main lens at the same angle through multiple different first target diffraction orders; the main lens is used for totally reflecting the light under the plurality of different preset wavelengths; and the metasurface coupling-out optical waveguide is used for coupling out the light which is totally reflected by the main lens and is under the different preset wavelengths at the same angle through a plurality of different second target diffraction levels. By implementing the method provided by the embodiment of the invention, the display effect of the AR display equipment can be improved.

Description

Technical Field

[0001] The present application relates to the field of optical metasurface technology, and in particular to a metasurface-based AR display device and a design method and apparatus thereof. Background Art

[0002] With the development of science and technology, three-dimensional display and human-computer interaction have gradually entered people's lives, such as intelligent driving assistance for vehicles, augmented reality (AR) swimming goggles, head-mounted virtual reality (VR) somatosensory games, and so on.

[0003] In the field of AR displays, traditional solutions primarily rely on optical waveguide structures designed with periodic gratings, including holographic diffraction waveguides, diffraction waveguides, and freeform surface solutions. In these solutions, 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. is the diffraction angle), it can be seen that when the grating period of each wavelength is the same and the diffraction order is 1, when the AR display device couples in and out light of different wavelengths, there will be deviations in the corresponding diffraction angles, which will cause color cast at the edge of the eye box of the AR display device, affecting the display effect of the AR display device. Summary of the Invention

[0005] The embodiments of the present application provide an AR display device based on a metasurface and a design method and apparatus thereof, which can avoid color cast 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, thereby improving the display effect of the AR display device.

[0006] In a first aspect, an embodiment of the present application provides an AR display device based on a metasurface, wherein the AR display device based on a metasurface includes a display device, a collimating device, a main lens, a metasurface in-coupling optical waveguide attached to the surface of the main lens, and a metasurface out-coupling optical waveguide attached to the surface of the main lens, wherein: The display device is used to load the virtual scene image; The collimating device is used to vertically incident the polychromatic light corresponding to the virtual scene image emitted by the display device into the metasurface coupling optical waveguide, wherein the polychromatic light includes light at multiple different preset wavelengths; The metasurface coupled-in optical waveguide is used to couple the light at the multiple different preset wavelengths into the main lens at the same angle through multiple different first target diffraction orders; The primary lens is configured to totally reflect the light at the plurality of different preset wavelengths; The metasurface out-coupling optical waveguide is used to couple out the light of the multiple different preset wavelengths that have been totally reflected by the main lens 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 are opposite in value.

[0007] In some embodiments, the display device is Lcos, Micro LED or Mini LED.

[0008] In some embodiments, the metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide are arranged on the first surface or the second surface of the main lens, the first surface is the side of the main lens close to the display device, and the second surface is the side of the main lens away from the display device.

[0009] In some embodiments, the main lens is made of glass or resin.

[0010] In a second aspect, an embodiment of the present application further provides a design method for an AR display device based on a metasurface, which is applied to the AR display device based on a metasurface according to the first aspect. The design method includes: Acquire the plurality of different preset wavelengths, the hyperatomic period, and the refractive index of the primary lens, wherein the hyperatomic period is the hyperatomic period corresponding to the initial metasurface coupling-in optical waveguide and the initial metasurface coupling-out optical waveguide; Determining the plurality of different first target diffraction orders, the plurality of different second target diffraction orders, and a target grating period based on a preset grating diffraction rule and the meta-atom period, the plurality of different preset wavelengths, and the refractive index; determining a first ideal phase distribution based on the plurality of different first target diffraction orders and the target grating period, and determining a second ideal phase distribution based on the plurality of different second target diffraction orders and the target grating period; determining a first evaluation function according to the first ideal phase distribution, and determining a second evaluation function according to the second ideal phase distribution; The initial metasurface in-coupling optical waveguide is optimized based on the first evaluation function to obtain a final metasurface in-coupling optical waveguide, and the initial metasurface out-coupling optical waveguide is optimized based on the second evaluation function to obtain a final metasurface out-coupling optical waveguide.

[0011] 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 a red light diffraction order, a green light diffraction order, and a blue light diffraction order; the preset grating diffraction rule includes a grating diffraction formula; and 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: Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the hyperatom period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is: ; in, is the target grating period, and , is a positive integer, is the superatomic period, is the preset red light wavelength, is the preset green light wavelength, is the preset blue light wavelength, is the red light diffraction order, is the green light diffraction order, is the diffraction order of the blue light, is the coupling angle of the metasurface into the optical waveguide, and , n is the refractive index; The plurality of different second target diffraction orders are determined according to inverse numbers of the plurality of different first target diffraction orders.

[0012] In some embodiments, determining a first evaluation function according to the first ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ; in, is the first evaluation function, , represents the number of superatoms within the target grating period, is the target grating period, is the super-atom period, N is the number of wavelengths of multiple different preset wavelengths, Refers to the super atom in position and wavelength Under the first ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under ; Determining a second evaluation function according to the second ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ; in, is the second evaluation function, Refers to the super atom in position and wavelength Under the second ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under .

[0013] In some embodiments, the optimizing the initial metasurface-coupled optical waveguide based on the first evaluation function to obtain a final metasurface-coupled optical waveguide includes: Performing a super-atom size update on the initial metasurface coupled-in optical waveguide based on the first evaluation function to obtain a first updated structure; Iteratively updating the first evaluation function based on the first update structure; If the first evaluation function is greater than a first preset threshold value and the number of iterations is less than the first preset iteration number threshold value, then continuing to perform super-atom size update on the first updated structure, and returning to the step of iteratively updating the first evaluation function based on the first updated 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 iteration threshold, the iterative update is stopped, and the corresponding first updated structure is used as the final metasurface coupled to the optical waveguide.

[0014] In some embodiments, the optimizing the initial metasurface out-coupling optical waveguide based on the second evaluation function to obtain a final metasurface out-coupling optical waveguide includes: Performing a super-atom size update on the initial metasurface outcoupling optical waveguide based on the second evaluation function to obtain a second updated structure; Iteratively updating the second evaluation function based on the second update structure; If the second evaluation function is greater than a second preset threshold and the number of iterations is less than the second preset iteration number threshold, continuing to perform super-atomic size update on the second updated structure, and returning to the step of iteratively updating the second evaluation function based on the second updated 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 iteration threshold, the iterative update is stopped, and the corresponding second updated structure is used as the final metasurface outcoupling optical waveguide.

[0015] In a third aspect, an embodiment of the present application further provides a design apparatus for an AR display device based on a metasurface, comprising: A transceiver unit, configured to obtain a plurality of different preset wavelengths, meta-atomic periods, and a refractive index of a primary lens, wherein the meta-atomic period is a meta-atomic period corresponding to an initial metasurface coupled-in optical waveguide and an initial metasurface coupled-out optical waveguide; A processing unit is used to determine the multiple different first target diffraction orders, the multiple different second target diffraction orders and the target grating period based on a preset grating diffraction rule, according to the meta-atomic period, the multiple different preset wavelengths and the refractive index; determine a first ideal phase distribution based on the multiple different first target diffraction orders and the target grating period, and determine a second ideal phase distribution based on the multiple different second target diffraction orders and the target grating period; 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; optimize the initial metasurface coupling-in optical waveguide based on the first evaluation function to obtain a final metasurface coupling-in optical waveguide, and optimize the initial metasurface coupling-out optical waveguide based on the second evaluation function to obtain a final metasurface coupling-out optical waveguide.

[0016] The present invention provides a metasurface-based AR display device and a design method and apparatus thereof. The metasurface-based AR display device includes a display device, a collimating device, a primary lens, a metasurface in-coupling optical waveguide attached to the surface of the primary lens, and a metasurface out-coupling optical waveguide attached to the surface of the primary lens, wherein: the display device is configured to load a virtual scene image; the collimating device is configured to vertically incident polychromatic light corresponding to the virtual scene image emitted by the display device into the metasurface in-coupling optical waveguide, wherein the polychromatic light includes light at multiple different preset wavelengths; the metasurface in-coupling optical waveguide is configured to couple the light at the multiple different preset wavelengths into the primary lens at the same angle through multiple different first target diffraction orders; the primary lens is configured to totally reflect the light at the multiple different preset wavelengths; and the metasurface out-coupling optical waveguide is configured to couple the light at the multiple different preset wavelengths totally reflected by the primary lens out at the same angle through multiple different second target diffraction orders, wherein the first target diffraction orders and the second target diffraction orders at the same preset wavelength are opposite in magnitude. The metasurface coupling-in optical waveguide and the metasurface coupling-out optical waveguide in the metasurface-based AR display device provided in the present application are provided with different diffraction orders for light at different preset wavelengths. Through different diffraction orders, light at different wavelengths can be coupled in and out at the same angle, thereby avoiding the color cast 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, thereby improving the display effect of the AR display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 Schematic diagram of the propagation of complex light by traditional waveguide; Figure 2 A schematic structural diagram of a metasurface-based AR display device provided in an embodiment of the present application; Figure 3 Schematic diagram of the propagation of polychromatic light by coupling the metasurface into the optical waveguide provided in an embodiment of the present application; Figure 4 A schematic flow chart of a design method for a metasurface-based AR display device provided in an embodiment of the present application; Figure 5 A schematic block diagram of a design apparatus for a metasurface-based AR display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0020] It will be understood that when used in this specification and the appended claims, the terms “comprises” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0021] It should also be understood that the terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the present 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.

[0022] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0023] See also Figure 1 , Figure 1 Figure 1 is a schematic diagram of the propagation of polychromatic light by a conventional waveguide. 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 to couple light into and out of different wavelengths, according to the diffraction formula: (where d represents the grating period, N represents the diffraction order, and λ represents the wavelength. is the diffraction angle), it can be seen that when the grating period of each wavelength is the same and the diffraction order is 1, when the traditional AR display device couples in and out light of different wavelengths, there will be deviations in the corresponding diffraction angles, which will cause color cast at the edge of the eye box of the AR display device, affecting the display effect of the AR display device.

[0024] In order to solve the above problems, an embodiment of the present application provides an AR display device based on a metasurface.

[0025] See also Figure 2 as well as Figure 3 , Figure 2 This is a schematic structural diagram of an AR display device based on a metasurface provided in this application. Figure 3This is a schematic diagram of the propagation of polychromatic light 10 by the metasurface-coupled optical waveguide provided in the present 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: The display device 20 is used to load a virtual scene image, wherein the display device 20 is arranged on the back focal plane of the collimator 30 to eliminate the light divergence angle and ensure that the light is incident on the main lens 40 / metasurface coupling optical waveguide 50 in a vertical direction; The collimating device 30 is used to vertically incident the polychromatic light corresponding to the virtual scene image emitted by the display device 20 onto the metasurface coupling optical waveguide 50, wherein the polychromatic light includes light at multiple different preset wavelengths; The metasurface coupling-in optical waveguide 50 is used to couple the light at the multiple different preset wavelengths into the main lens 40 at the same angle through multiple different first target diffraction orders; The main lens 40 is used to totally reflect the light at the multiple different preset wavelengths; The metasurface outcoupling optical waveguide 60 is used to couple out the light of the multiple different preset wavelengths totally reflected by the main lens 40 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 are opposite in value.

[0026] In this embodiment, the metasurface coupling-in optical waveguide 50 and the metasurface coupling-out optical waveguide 60 in the metasurface-based AR display device are provided with different diffraction orders for light at different preset wavelengths. Through different diffraction orders, light at different wavelengths can be coupled out and coupled in at the same angle, thereby avoiding the color cast 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, thereby improving the display effect of the AR display device.

[0027] In some embodiments, the display device 20 is a liquid crystal on silicon (LCOS), a micro light emitting diode (Micro LED) or a sub-millimeter light emitting diode (Miniature Light Emitting Diode, Mini LED).

[0028] In some embodiments, the metasurface in-coupling optical waveguide 50 and the metasurface out-coupling optical waveguide 60 are disposed on the first surface or the second surface of the primary lens 40. The first surface is the side of the primary lens 40 close to the display device 20, and the second surface is the side of the primary lens 40 away from the display device 20. Figure 2 , Figure 2 The metasurface coupling-in optical waveguide 50 and the metasurface coupling-out optical waveguide 60 are arranged on the second surface of the main lens 40. It can be seen that when the metasurface coupling-in optical waveguide 50 and the metasurface coupling-out optical waveguide 60 are arranged on the second surface, light at multiple different preset wavelengths needs to pass through the main lens 40 and then be vertically incident on the metasurface coupling-in optical waveguide 50 after being collimated by the collimating device 30; if they are arranged on the first surface, light at multiple different preset wavelengths can be directly vertically incident on the metasurface coupling-in optical waveguide 50 after being collimated by the collimating device 30.

[0029] In some embodiments, the main lens 40 is made of glass or resin. In this embodiment, the principle for selecting the material of the main lens 40 is that the higher the refractive index, the better, and the higher the light transmittance, the better, because the higher the refractive index, the wider the transmission angle range of the main lens 40, and the higher the light transmittance, the more realistic the real scene perceived by the wearer, which is conducive to improving the viewing experience.

[0030] Furthermore, the waveguides (metasurface in-coupling optical waveguide 50 and metasurface out-coupling optical waveguide 60) in the metasurface-based AR display device provided by this application are directly bonded to the surface of the primary lens 40, with a thickness of only micrometers (nano-pillar structure). Compared to traditional discrete optical components (such as prisms and reflectors), this significantly reduces the size and weight of the optical components in the AR display device, improving user comfort when wearing the AR display device.

[0031] like Figure 4 As shown, the embodiment of the present application further provides a design method for an AR display device based on a metasurface, which is applied to the AR display device based on the metasurface as described above. The embodiment of the present application takes multiple different preset wavelengths including a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength as an example for explanation. The design method mainly describes the design of a metasurface coupling-in optical waveguide and a metasurface coupling-out optical waveguide in the AR display device based on the metasurface. The design method includes: steps S110 to S150: S110, obtaining the multiple different preset wavelengths, the meta-atomic period, and the refractive index of the primary lens, wherein the meta-atomic period is the meta-atomic period corresponding to the initial metasurface coupling-in optical waveguide and the initial metasurface coupling-out optical waveguide.

[0032] In this embodiment, before designing the metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide, it is first necessary to determine the values ​​of multiple different preset wavelengths in the polychromatic light entering the metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide.

[0033] In a specific embodiment, the preset red light wavelength 660nm, preset green wavelength 550nm, preset blue light wavelength It is 437nm.

[0034] Among them, the hyperatomic period p can be determined according to the structural characteristics of the metasurface, for example, p=350nm, and the refractive index of the main lens is determined by the structural characteristics of the main lens material, and the higher the refractive index, the better.

[0035] S120. Based on a preset grating diffraction rule, determine the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period according to the super-atom period, the multiple different preset wavelengths, and the refractive index.

[0036] 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 a red light diffraction order, a green light diffraction order, and a blue light diffraction order; the preset grating diffraction rule includes a grating diffraction formula; and step S120 includes: Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the hyperatom period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is: ; in, is the target grating period, and , is a positive integer, is the superatomic period, is the preset red light wavelength, is the preset green light wavelength, is the preset blue light wavelength, is the red light diffraction order, is the green light diffraction order, is the diffraction order of the blue light, is the coupling angle of the metasurface into the optical waveguide, and , n is the refractive index; The plurality of different second target diffraction orders are determined according to inverse numbers of the plurality of different first target diffraction orders.

[0037] Specifically, the diffraction order and target grating period corresponding to each wavelength are solved so that the obtained diffraction order and target grating period can satisfy the grating diffraction formula and the target grating period can be divided by the atomic period p. In addition, the coupling angle of the metasurface into the optical waveguide needs to be greater than .

[0038] In a specific embodiment, after obtaining a plurality of different first target diffraction orders, the inverse of the plurality of different first target diffraction orders is taken to obtain a plurality of different second target diffraction orders, for example, the red light diffraction order among the plurality of different first target diffraction orders. =+4, green light diffraction order =+5 and blue light diffraction order = +6; the plurality of different second target diffraction orders also include red diffraction orders, green diffraction orders and blue diffraction orders, and the red diffraction orders in the plurality of different second target diffraction orders are =-4, green light diffraction order =-5 and blue light diffraction order =-6.

[0039] In a specific embodiment, the calculated target grating period is 3500 nm.

[0040] S130. Determine a first ideal phase distribution according to the multiple different first target diffraction orders and the target grating period, and determine a second ideal phase distribution according to the multiple different second target diffraction orders and the target grating period.

[0041] In this embodiment, since the incident and exit angles of the light for the metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide are different (opposite), this embodiment requires the design of the surface in-coupling optical waveguide and the metasurface out-coupling optical waveguide separately. First, a first ideal phase distribution and a second ideal phase distribution are determined, respectively.

[0042] Specifically, this embodiment can determine the above-mentioned first ideal phase distribution and second ideal phase distribution through a multi-order diffraction phase mapping method (a mathematical modeling method based on multi-order diffraction theory that calculates the ideal phase distribution of the metasurface by presetting the wavelength, diffraction order and grating period).

[0043] Among them, when the phase distribution of the metasurface coupled into the optical waveguide is in the first ideal phase distribution, the energy of light of different wavelengths in the output light (light coupled into the main lens) can be mainly concentrated in the corresponding target diffraction order; when the phase distribution of the metasurface coupled out of the optical waveguide is in the second ideal phase distribution, the energy of light of different wavelengths in the output light (light coupled out into the air (entering the human eye)) can be mainly concentrated in the corresponding target diffraction order.

[0044] S140: 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.

[0045] Specifically, in some embodiments, the first evaluation function is calculated according to the following formula: ; in, is the first evaluation function, , represents the number of superatoms within the target grating period, is the target grating period, is the super-atom period, N is the number of wavelengths of multiple different preset wavelengths, Refers to the super atom in position and wavelength Under the first ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under ; Determining a second evaluation function according to the second ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ; in, is the second evaluation function, Refers to the super atom in position and wavelength Under the second ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under .

[0046] S150. Optimizing the initial metasurface in-coupling optical waveguide based on the first evaluation function to obtain a final metasurface in-coupling optical waveguide, and optimizing the initial metasurface out-coupling optical waveguide based on the second evaluation function to obtain a final metasurface out-coupling optical waveguide.

[0047] Specifically, in some embodiments, the optimizing the initial metasurface-coupled optical waveguide based on the first evaluation function to obtain a final metasurface-coupled optical waveguide includes: Performing a super-atom size update on the initial metasurface coupled-in optical waveguide based on the first evaluation function to obtain a first updated structure; Iteratively updating the first evaluation function based on the first update structure; If the first evaluation function is greater than a first preset threshold value and the number of iterations is less than the first preset iteration number threshold value, then continuing to perform super-atom size update on the first updated structure, and returning to the step of iteratively updating the first evaluation function based on the first updated 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 iteration threshold, the iterative update is stopped, and the corresponding first updated structure is used as the final metasurface coupled to the optical waveguide.

[0048] Specifically, during iteration, a particle swarm optimization algorithm may be used to make the actual phase distribution match the corresponding first ideal phase distribution as much as possible.

[0049] Similarly, the optimizing process of the initial metasurface out-coupling optical waveguide based on the second evaluation function to obtain the final metasurface out-coupling optical waveguide includes: Performing a super-atom size update on the initial metasurface outcoupling optical waveguide based on the second evaluation function to obtain a second updated structure; Iteratively updating the second evaluation function based on the second update structure; If the second evaluation function is greater than a second preset threshold and the number of iterations is less than the second preset iteration number threshold, continuing to perform super-atomic size update on the second updated structure, and returning to the step of iteratively updating the second evaluation function based on the second updated 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 iteration threshold, the iterative update is stopped, and the corresponding second updated structure is used as the final metasurface outcoupling optical waveguide.

[0050] Specifically, during iteration, a particle swarm optimization algorithm may be used to make the actual phase distribution match the corresponding second ideal phase distribution as much as possible.

[0051] In this embodiment, the optimized metasurface in-coupling optical waveguide and metasurface out-coupling optical waveguide can ensure that after polychromatic light is incident at the same angle, the reflected light angle remains consistent at different wavelengths, thereby ensuring that light of different wavelengths in the polychromatic light is coupled out at the same angle after passing through the metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide. This can avoid the occurrence of color cast 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, thereby improving the display effect of the AR display device.

[0052] like Figure 5 As shown, the embodiment of the present application further provides a design device 500 for an AR display device based on a metasurface, the device 500 comprising: The transceiver unit 501 is configured to obtain a plurality of different preset wavelengths, meta-atomic periods, and a refractive index of a primary lens, wherein the meta-atomic period is a meta-atomic period corresponding to an initial metasurface coupled-in optical waveguide and an initial metasurface coupled-out optical waveguide; The processing unit 502 is used to determine the multiple different first target diffraction orders, the multiple different second target diffraction orders and the target grating period based on the preset grating diffraction rule, the meta-atomic period, the multiple different preset wavelengths and the refractive index; determine a first ideal phase distribution based on the multiple different first target diffraction orders and the target grating period, and determine a second ideal phase distribution based on the multiple different second target diffraction orders and the target grating period; 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; optimize the initial metasurface coupling-in optical waveguide based on the first evaluation function to obtain a final metasurface coupling-in optical waveguide, and optimize the initial metasurface coupling-out optical waveguide based on the second evaluation function to obtain a final metasurface coupling-out optical waveguide.

[0053] In some embodiments, the multiple different preset wavelengths include a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength; the multiple different first target diffraction orders include a red light diffraction order, a green light diffraction order, and a blue light diffraction order; and the preset grating diffraction rule includes a grating diffraction formula; when the processing unit executes the step of determining the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period based on the preset grating diffraction rule according to the meta-atomic period, the multiple different preset wavelengths, and the refractive index, the processing unit is specifically configured to: Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the hyperatom period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is: ; in, is the target grating period, and , is a positive integer, is the superatomic period, is the preset red light wavelength, is the preset green light wavelength, is the preset blue light wavelength, is the red light diffraction order, is the green light diffraction order, is the diffraction order of the blue light, is the coupling angle of the metasurface into the optical waveguide, and , n is the refractive index; The plurality of different second target diffraction orders are determined according to inverse numbers of the plurality of different first target diffraction orders.

[0054] In some embodiments, when executing the step of determining the first evaluation function according to the first ideal phase distribution, the processing unit is specifically configured to: The first evaluation function is calculated according to the following formula: ; in, is the first evaluation function, , represents the number of superatoms within the target grating period, is the target grating period, is the super-atom period, N is the number of wavelengths of multiple different preset wavelengths, Refers to the super atom in position and wavelength Under the first ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under ; Determining a second evaluation function according to the second ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ; in, is the second evaluation function, Refers to the super atom in position and wavelength Under the second ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under .

[0055] 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 configured to: Performing a super-atom size update on the initial metasurface coupled-in optical waveguide based on the first evaluation function to obtain a first updated structure; Iteratively updating the first evaluation function based on the first update structure; If the first evaluation function is greater than a first preset threshold value and the number of iterations is less than the first preset iteration number threshold value, then continuing to perform super-atom size update on the first updated structure, and returning to the step of iteratively updating the first evaluation function based on the first updated 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 iteration threshold, the iterative update is stopped, and the corresponding first updated structure is used as the final metasurface coupled to the optical waveguide.

[0056] In some embodiments, when the processing unit performs the step of optimizing the initial metasurface out-coupling optical waveguide based on the second evaluation function to obtain the final metasurface out-coupling optical waveguide, it is specifically configured to: Performing a super-atom size update on the initial metasurface outcoupling optical waveguide based on the second evaluation function to obtain a second updated structure; Iteratively updating the second evaluation function based on the second update structure; If the second evaluation function is greater than a second preset threshold and the number of iterations is less than the second preset iteration number threshold, continuing to perform super-atomic size update on the second updated structure, and returning to the step of iteratively updating the second evaluation function based on the second updated 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 iteration threshold, the iterative update is stopped, and the corresponding second updated structure is used as the final metasurface outcoupling optical waveguide.

[0057] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of this application, several improvements and modifications can be made to this application, and these improvements and modifications also fall within the scope of protection of the claims of this application.

[0058] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. An AR display device based on a metasurface, characterized in that: The metasurface-based AR display device includes a display device, a collimating device, a main lens, a metasurface in-coupling optical waveguide attached to the surface of the main lens, and a metasurface out-coupling optical waveguide attached to the surface of the main lens, wherein: The display device is used to load the virtual scene image; The collimating device is used to vertically incident the polychromatic light corresponding to the virtual scene image emitted by the display device into the metasurface coupling optical waveguide, wherein the polychromatic light includes light at multiple different preset wavelengths; The metasurface coupled-in optical waveguide is used to couple the light at the multiple different preset wavelengths into the main lens at the same angle through multiple different first target diffraction orders; The primary lens is configured to totally reflect the light at the plurality of different preset wavelengths; The metasurface out-coupling optical waveguide is used to couple out the light of the multiple different preset wavelengths that have been totally reflected by the main lens 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 are opposite in value.

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

3. The metasurface-based AR display device according to claim 1, wherein: The metasurface in-coupling optical waveguide and the metasurface out-coupling optical waveguide are arranged on the first surface or the second surface of the main lens, the first surface is the side of the main lens close to the display device, and the second surface is the side of the main lens away from the display device.

4. The metasurface-based AR display device according to claim 1, wherein: The main lens is made of glass or resin.

5. A design method for an AR display device based on a metasurface, applied to the AR display device based on a metasurface according to any one of claims 1 to 4, characterized in that: The design method includes: Acquire the plurality of different preset wavelengths, the hyperatomic period, and the refractive index of the primary lens, wherein the hyperatomic period is the hyperatomic period corresponding to the initial metasurface coupling-in optical waveguide and the initial metasurface coupling-out optical waveguide; Determining the plurality of different first target diffraction orders, the plurality of different second target diffraction orders, and a target grating period based on a preset grating diffraction rule and the meta-atom period, the plurality of different preset wavelengths, and the refractive index; determining a first ideal phase distribution based on the plurality of different first target diffraction orders and the target grating period, and determining a second ideal phase distribution based on the plurality of different second target diffraction orders and the target grating period; determining a first evaluation function according to the first ideal phase distribution, and determining a second evaluation function according to the second ideal phase distribution; The initial metasurface in-coupling optical waveguide is optimized based on the first evaluation function to obtain a final metasurface in-coupling optical waveguide, and the initial metasurface out-coupling optical waveguide is optimized based on the second evaluation function to obtain a final metasurface out-coupling optical waveguide.

6. The method according to claim 5, characterized in that The multiple different preset wavelengths include a preset red light wavelength, a preset green light wavelength, and a preset blue light wavelength; the multiple different first target diffraction orders include a red light diffraction order, a green light diffraction order, and a blue light diffraction order; the preset grating diffraction rule includes a grating diffraction formula; the preset grating diffraction rule determines the multiple different first target diffraction orders, the multiple different second target diffraction orders, and the target grating period according to the super-atomic period, the multiple different preset wavelengths, and the refractive index, including: Based on the grating diffraction formula, the multiple different first target diffraction orders and the target grating period are determined according to the hyperatom period, the multiple different preset wavelengths, and the refractive index. The grating diffraction formula is: ； in, is the target grating period, and , is a positive integer, is the superatomic period, is the preset red light wavelength, is the preset green light wavelength, is the preset blue light wavelength, is the red light diffraction order, is the green light diffraction order, is the diffraction order of the blue light, is the coupling angle of the metasurface into the optical waveguide, and , n is the refractive index; The plurality of different second target diffraction orders are determined according to inverse numbers of the plurality of different first target diffraction orders.

7. The method according to claim 5, characterized in that The determining of a first evaluation function according to the first ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ； in, is the first evaluation function, , represents the number of superatoms within the target grating period, is the target grating period, is the super-atom period, N is the number of wavelengths of multiple different preset wavelengths, Refers to the super atom in position and wavelength Under the first ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under ; Determining a second evaluation function according to the second ideal phase distribution includes: The first evaluation function is calculated according to the following formula: ； in, is the second evaluation function, Refers to the super atom in position and wavelength Under the second ideal phase distribution, Refers to the super atom in position and wavelength The actual phase distribution under .

8. The method according to claim 5, characterized in that The optimizing process of the initial metasurface coupled-in optical waveguide based on the first evaluation function to obtain a final metasurface coupled-in optical waveguide includes: Performing a super-atom size update on the initial metasurface coupled-in optical waveguide based on the first evaluation function to obtain a first updated structure; Iteratively updating the first evaluation function based on the first update structure; If the first evaluation function is greater than a first preset threshold value and the number of iterations is less than the first preset iteration number threshold value, then continuing to perform super-atom size update on the first updated structure, and returning to the step of iteratively updating the first evaluation function based on the first updated 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 iteration threshold, the iterative update is stopped, and the corresponding first updated structure is used as the final metasurface coupled to the optical waveguide.

9. The method according to claim 5, characterized in that The optimizing process of the initial metasurface out-coupling optical waveguide based on the second evaluation function to obtain a final metasurface out-coupling optical waveguide comprises: Performing a super-atom size update on the initial metasurface outcoupling optical waveguide based on the second evaluation function to obtain a second updated structure; Iteratively updating the second evaluation function based on the second update structure; If the second evaluation function is greater than a second preset threshold and the number of iterations is less than the second preset iteration number threshold, continuing to perform super-atomic size update on the second updated structure, and returning to the step of iteratively updating the second evaluation function based on the second updated 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 iteration threshold, the iterative update is stopped, and the corresponding second updated structure is used as the final metasurface outcoupling optical waveguide.

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

Images