A Micro LED waveguide AR glasses on-chip integrated system

Abstract

The present invention provides an on-chip integrated system for Micro LED (Micro LED) optical waveguide AR glasses, relating to the field of optical imaging technology. The system comprises a dielectric substrate layer; an optical waveguide layer disposed on the dielectric substrate layer; and a nanostructure layer disposed on the optical waveguide layer, the nanostructure layer comprising a supercoupler and a waveguide-driven metasurface. The supercoupler comprises a polarization-independent unit structure and is used to couple a vertically incident collimated light beam from a Micro LED into the optical waveguide layer at a set angle to form a waveguide-mode light. The waveguide-driven metasurface is used to decouple the waveguide-mode light into free space, forming a controllable light field. The present invention achieves efficient optical coupling and decoupling through the polarization-independent supercoupler and the waveguide-driven metasurface. Combined with the one-to-one integrated design of Micro LEDs and strip waveguides, the system significantly improves the display quality and volume of AR glasses, eliminates optical crosstalk, and enhances wearing comfort and optical performance.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to an on-chip integrated system for Micro LED optical waveguide AR glasses. Background Art

[0002] Augmented reality (AR) and virtual reality (VR) technologies have developed rapidly in recent years. Near-eye display systems, as core components, play a key role in achieving an immersive experience. In AR devices, the optical display system typically consists of a microdisplay and optical components. Currently, microdisplays mostly use Micro LEDs. Utilizing optical waveguide technology, the display and imaging system can be moved to the top or side of the forehead. This design significantly reduces the optical system's obstruction of the user's view of the outside world and makes the device's weight distribution more ergonomic, significantly improving the wearing experience.

[0003] However, existing AR glasses technology faces several pressing challenges. Traditional optical components (such as prisms and gratings) are bulky in the coupling and decoupling stages between free-space light and waveguides. This not only limits the flexibility of optical operations but also hinders overall system integration. Furthermore, these traditional components have limited functionality and are unable to meet the growing demand for high-performance displays.

[0004] From the perspective of Micro LED manufacturing, existing coupling technologies place high demands on the polarization of Micro LEDs, which increases the complexity of manufacturing and causes energy loss during polarization adjustment, thus affecting the display quality. Furthermore, because existing technologies struggle to achieve precise one-to-one coupling between Micro LEDs and optical waveguides, crosstalk between light from different Micro LEDs coupled into the same waveguide can severely interfere with display quality, resulting in reduced image clarity and color reproduction.

[0005] In summary, existing AR glasses technology has many shortcomings in optical coupling elements, Micro LED process preparation, and coupling accuracy. An innovative technical solution is urgently needed to solve these problems in order to improve the display performance and user experience of AR glasses. Summary of the Invention

[0006] To this end, embodiments of the present invention provide an on-chip integrated system for Micro LED optical waveguide AR glasses, which is used to solve the problems in the prior art of coupling between free-space light and waveguides, the bulky decoupling optical components that restrict the freedom of optical operation and have limited functions, as well as the high complexity of Micro LED process preparation, large polarization adjustment loss, and the crosstalk easily generated when different Micro LED lights are coupled into the same waveguide, which affects the display effect.

[0007] To solve the above problems, an embodiment of the present invention provides an on-chip integrated system for Micro LED optical waveguide AR glasses, the system comprising:

[0008] dielectric substrate layer;

[0009] an optical waveguide layer, disposed on the dielectric substrate layer;

[0010] a nanostructure layer located on the optical waveguide layer, wherein the nanostructure layer includes a supercoupler and a waveguide-driven metasurface;

[0011] The supercoupler is composed of a polarization-independent unit structure, which is used to couple the collimated light beam of the Micro LED vertically incident into the optical waveguide layer at a set angle to form a waveguide mode light; the waveguide-driven metasurface is used to decouple the waveguide mode light into free space to form a controllable light field.

[0012] Preferably, the unit structure of the supercoupler includes a cylinder or a square cylinder, whose size parameters are arranged through phase gradient so that the vertically incident collimated light beam undergoes abnormal refraction and satisfies the waveguide total reflection condition, thereby realizing the coupling of free space light to waveguide mode light.

[0013] Preferably, the supercoupler and the Micro LED are in a one-to-one correspondence, each Micro LED is independently coupled to a corresponding strip waveguide channel, and the strip waveguide channel is formed in the optical waveguide layer by etching to avoid crosstalk during light transmission.

[0014] Preferably, the unit structure of the waveguide-driven metasurface is designed through periodic displacement of nanocolumns and phase mutation to extract the waveguide mode light and superimpose the transmitted accumulated phase to achieve arbitrary wavefront control of the decoupled light field.

[0015] Preferably, the refractive index of the material of the optical waveguide layer is higher than that of the dielectric substrate layer and the air cladding, satisfying the total reflection transmission condition of the guided wave mode light, and the waveguide thickness is limited to single-mode transmission.

[0016] Preferably, the nanocolumn structural parameters of the supercoupler and the waveguide-driven metasurface are optimized by a particle swarm algorithm or a genetic algorithm to improve the coupling efficiency and decoupling accuracy of the target wavelength.

[0017] Preferably, the optical waveguide layer is a strip waveguide array, the arrangement of which is consistent with the geometric distribution of the Micro LED array, and each strip waveguide corresponds to a Micro LED light source.

[0018] Preferably, the waveguide-driven metasurface and the supercoupler are separately arranged in the nanostructure layer and do not satisfy reciprocity, allowing only unidirectional coupling of free-space light through the supercoupler and unidirectional decoupling of waveguide mode light through the waveguide-driven metasurface.

[0019] Preferably, the transmittance of the unit structure of the supercoupler is greater than a set threshold, and its phase library covers the range of 0 to 2π, and the light field distribution is verified by time-domain finite difference simulation.

[0020] Preferably, the decoupled light field of the waveguide-driven metasurface is used for holographic imaging or augmented reality display, and the light field control range covers the field of view of the human eye.

[0021] It can be seen from the above technical solutions that the present invention has the following beneficial effects:

[0022] (1) The present invention utilizes a phase gradient metasurface composed of a polarization-independent unit structure in a supercoupler, which can accurately couple the vertically incident collimated light beam of Micro LED to the optical waveguide layer. In addition, the waveguide-driven metasurface can realize arbitrary wavefront control and decoupling of the waveguide mode light, effectively improving the transmission and control efficiency of light and ensuring the quality and clarity of the display image.

[0023] (2) The supercoupler of the present invention has a one-to-one correspondence with the Micro LED. Each Micro LED is independently coupled to a corresponding strip waveguide channel. The channel is formed in the optical waveguide layer by etching, which greatly avoids the crosstalk problem during light transmission, making each optical path independent and stable, thereby enhancing the accuracy and stability of the display effect.

[0024] (3) The structural parameters of the optical waveguide layer, supercoupler, and waveguide-driven metasurface of the present invention can be optimized using particle swarm optimization algorithms, and the components of the nanostructured layer are separated and unidirectional. This design not only facilitates flexible adjustment according to different needs, but also improves the coupling efficiency and decoupling accuracy of the target wavelength, enhancing the applicability and performance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the implementation cases of the present invention or the technical solutions in the prior art, the following is a brief description of the drawings required for use in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be understood as limiting the present invention in any way. Those skilled in the art can derive other drawings based on these drawings without inventive effort. Among them:

[0026] Figure 1 A schematic diagram of an on-chip integrated system for Micro LED optical waveguide AR glasses provided by the present invention;

[0027] Figure 2 Schematic diagram of the structural principle of the supercoupler of the present invention;

[0028] Figure 3Schematic diagram of the principle of the waveguide driven metasurface structure of the present invention;

[0029] Figure 4 This is a schematic structural diagram of an on-chip integrated system for Micro LED optical waveguide AR glasses provided by the present invention.

[0030] Description of the accompanying drawings in the specification: 1. dielectric substrate layer; 2. optical waveguide layer; 31. supercoupler; 32. waveguide-driven metasurface. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] Example 1:

[0033] In order to solve the problems in the existing technology of coupling and decoupling between free space light and waveguide (mode light), the bulky optical components restrict the freedom of optical operation and have limited functions, as well as the high complexity of Micro LED process preparation, large polarization adjustment loss, and the crosstalk caused by different Micro LED lights coupled into the same waveguide that affects the display effect. Figure 1 As shown, the present invention proposes an on-chip integrated system for Micro LED optical waveguide AR glasses, which includes:

[0034] dielectric substrate layer 1;

[0035] The optical waveguide layer 2 is provided on the dielectric substrate layer 1;

[0036] A nanostructure layer is located on the optical waveguide layer 2, and the nanostructure layer includes a supercoupler 31 and a waveguide driven metasurface 32;

[0037] The supercoupler 31 is composed of a polarization-independent unit structure, which is used to couple the collimated light beam of the Micro LED vertically incident into the optical waveguide layer 2 at a set angle to form a waveguide mode light; the waveguide driven metasurface 32 is used to decouple the waveguide mode light into free space to form a controllable light field.

[0038] As can be seen from the above technical solution, the present invention proposes an on-chip integrated system for Micro LED optical waveguide AR glasses. The supercoupler of the present invention is composed of a polarization-independent unit structure, which has a precise one-to-one correspondence with the Micro LED. Through a unique phase gradient arrangement and strip waveguide channel design, it can not only efficiently couple a vertically incident collimated light beam to the optical waveguide layer, but also avoid optical crosstalk, ensuring imaging accuracy. The refractive index of the optical waveguide layer material is carefully selected to be higher than that of the dielectric substrate layer and the air cladding, and is limited to single-mode transmission, ensuring stable total reflection transmission of the waveguide mode light and reducing interference. The waveguide-driven metasurface can achieve arbitrary wavefront control of the waveguide mode light through the periodic displacement and phase mutation design of the nanopillars, accurately decoupling it into free space, covering the human eye's field of view, and is suitable for holographic imaging or augmented reality display. In addition, the nanopillar structural parameters of the supercoupler and waveguide-driven metasurface are optimized with the help of particle swarm optimization and other methods to further improve the coupling efficiency and decoupling accuracy. The overall solution significantly improves the optical performance and display effect of Micro LED optical waveguide AR glasses, bringing users a better AR experience.

[0039] Furthermore, the Micro LED optical waveguide AR glasses on-lens integrated system of the present invention mainly consists of a dielectric substrate layer 1, an optical waveguide layer 2, and a nanostructure layer. The nanostructure layer is located on the optical waveguide layer 2 and includes a supercoupler 31 and a waveguide-driven metasurface 32.

[0040] In this embodiment, the supercoupler 31 is composed of polarization-independent unit structures, such as cylindrical or square prisms. Its design is based on the dimensions of the Micro LED, aiming to couple a vertically incident collimated light beam from the Micro LED into the optical waveguide layer 2 at a set angle, generating guided wavemode light. During the design process, the unit structure was simulated using FDTD (Finite Difference Time Domain) simulation software. By varying parameters such as the period (P), diameter (D), and height (H) of the unit structure, the phase of the incident light field can be manipulated. The unit structures are arranged according to the desired phase, causing anomalous refraction of the vertically incident collimated light beam. When the transmission angle meets the waveguide's total internal reflection condition, free-space light can be coupled into the waveguide and transmitted in the fundamental mode (TE or TM), thus achieving coupling of free-space light to guided wavemode light.

[0041] To ensure the performance of supercoupler 31, its unit structure transmittance must exceed a set threshold (set at 80% in this example), and the phase library must cover the range from 0 to 2π. FDTD simulation software can be used to determine the optical field distribution of free-space light coupled into the waveguide of supercoupler 31, verifying the rationality of its design. For example, in an actual design, for a specific Micro LED, multiple simulations and optimizations are performed to determine the unit structure's period (P), diameter (D), and height (H) to achieve the ideal coupling effect.

[0042] like Figure 2 As shown, the supercoupler 31 uses a nanostructure of a phase gradient metasurface, which can couple vertically incident linearly polarized light in free space into a waveguide. The coupling principle and design basis of the supercoupler 31 are as follows:

[0043] In the design of the supercoupler 31 of the integrated system of the Micro LED optical waveguide AR glasses, according to the generalized Snell's law, the refraction angle and the incident angle of the plane light incident from free space after passing through the interface must satisfy a specific relationship, that is, .

[0044] In practical application scenarios, when free space light is incident vertically, that is, the incident angle , and the refraction angle and waveguide refractive index The product of is equal to the effective refractive index of a waveguide mode ( ), the formula can be simplified to .

[0045] Based on this principle, when designing the supercoupler 31 unit structure, as long as the phase gradient at the interface is reasonably controlled, , metasurfaces can achieve the conversion of free-space light into arbitrary guided wavemode light. For example, in the design of a supercoupler 31 for a specific Micro LED light source and waveguide system, by precisely calculating and controlling the phase gradient, adjusting the dimensional parameters of the supercoupler 31 unit structure (such as a cylinder or square prism), and arranging them according to the phase gradient, a vertically incident collimated light beam undergoes anomalous refraction, satisfying the waveguide's total internal reflection condition, thereby successfully achieving efficient coupling of free-space light into guided wavemode light.

[0046] In addition, it is worth noting that The positive or negative sign of the term determines the direction of coupling, which needs to be carefully considered in the actual design process to ensure that light is coupled into the waveguide in the expected direction, laying the foundation for subsequent guided wave mode light transmission and decoupling display.

[0047] In this embodiment, the waveguide-driven metasurface 32 is used to decouple the guided wave mode light into free space, forming a controllable light field. Its unit structure utilizes nanopillar periodic displacement and phase mutation. During the guided wave mode light transmission process, the nanopillar displacement within the period is used to extract light of different phases, with a 2π period. The accumulated phases are then superimposed and transmitted, achieving arbitrary wavefront control of the decoupled light field.

[0048] like Figure 3 As shown, it is assumed that the initial phase of the incident guided wave mode light is , when the guided wave mode light passes through the first nanorod, the phase of the coupled light decoupled into the free space becomes ,in The phase jump provided by the first nanopillar. When the light reaches the second nanopillar position, the phase of the light coupled from the second nanopillar to the free space is , is the propagation constant of the guided mode light, is the phase change caused by phase accumulation during transmission. Let the initial phase , the initial position x=0, then the total phase of the coupled light at different x positions is From the above formula, it can be clearly seen that the total phase of the light coupled into free space is It consists of two parts: the phase jump provided by superatoms at different x positions ; Phase accumulation of guided wave mode light during transmission By rationally designing the parameters and displacement of the nanopillars, the phase distribution of the decoupled light field can be precisely controlled to meet the needs of holographic imaging or augmented reality display, and the light field control range covers the human eye's field of view.

[0049] In this embodiment, the optical waveguide layer 2 is disposed above the dielectric substrate layer 1. Its material has a higher refractive index than both the dielectric substrate layer 1 and the air cladding. This ensures total internal reflection of the guided wave mode light, ensuring stable light transmission within the waveguide. When selecting the material for the optical waveguide layer 2, the transmission loss and dispersion characteristics of different materials for light in different wavelength bands must be considered. Furthermore, the waveguide thickness is limited to single-mode transmission to reduce inter-mode interference and ensure display stability. Ansys Lumerical's FDE (finite-difference eigenmode) simulation accurately models the waveguide and coupler performance and determines the appropriate waveguide thickness and other structural parameters.

[0050] Furthermore, the system preparation and optimization process of the present invention includes:

[0051] (1) Preparation of strip waveguide array: According to the arrangement of Micro LED array, the optical waveguide layer 2 is photolithographically and etched to form a strip waveguide array. Figure 4 As shown, each strip waveguide corresponds to a Micro LED light source, and its arrangement is consistent with the geometric distribution of the Micro LED array. In this way, each Micro LED is independently coupled to its corresponding strip waveguide channel, avoiding crosstalk during light transmission and ensuring display clarity and accuracy.

[0052] (2) Preparation of the nanostructure layer: In the nanostructure layer, a supercoupler 31 and a waveguide-driven metasurface 32 are prepared according to the needs of coupling Micro LEDs into optical waveguides and decoupling modulated waveguides. The supercoupler 31 and the waveguide-driven metasurface 32 are arranged separately in the nanostructure layer and do not satisfy reciprocity. They only allow free-space light to be unidirectionally coupled through the supercoupler 31 and waveguide mode light to be unidirectionally decoupled through the waveguide-driven metasurface 32. During the preparation process, the size, shape, and position of the nanopillars are precisely controlled through processes such as photolithography and etching to ensure that their performance meets the design requirements.

[0053] (3) Structural parameter optimization: The nanopillar structural parameters of the supercoupler 31 and the waveguide-driven metasurface 32 are optimized using optimization algorithms such as particle swarm optimization or genetic algorithm. Taking the particle swarm algorithm as an example, during the optimization process, the coupling efficiency and decoupling accuracy are used as optimization targets, and the size, shape, spacing and other parameters of the nanopillars are continuously adjusted. After multiple iterative calculations, the optimal parameter combination is found, which improves the coupling efficiency and decoupling accuracy of the target wavelength and further enhances the display effect of the system.

[0054] Furthermore, the system of the present invention operates as follows: the collimated Micro LED light beam is perpendicularly incident on the corresponding supercoupler 31. The supercoupler 31 couples the light beam into the optical waveguide layer 2, forming a waveguide mode light. The waveguide mode light propagates in the waveguide and, upon reaching the waveguide-driven metasurface 32, is decoupled into free space, forming a controllable light field. This light field is received by both eyes and used for holographic imaging or augmented reality display. Throughout this process, the incident position of the Micro LED and the unit nanopillar structure (size, shape, and spacing) of the supercoupler 31 are optimized to improve coupling efficiency and ensure the display effect. For example, in a practical application scenario, when a user wears AR glasses to view a virtual scene, the light emitted by the Micro LED is coupled into the waveguide through the supercoupler 31 and then decoupled into free space by the waveguide-driven metasurface 32, forming a clear and realistic virtual image that is presented to the user, achieving an immersive augmented reality experience.

[0055] In summary, the on-chip integrated system for Micro LED waveguide AR glasses of the present invention effectively addresses the shortcomings of existing technologies through unique structural design, preparation process, and parameter optimization, significantly improving the display effect of Micro LED in waveguide AR glasses applications, and has important practical value and market prospects.

[0056] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications derived therefrom remain within the scope of protection of the present invention.

Claims

1. A micro LED waveguide AR glasses on-chip integrated system, characterized by: include: dielectric substrate layer; An optical waveguide layer is provided on the dielectric substrate layer. The optical waveguide layer is a strip waveguide array whose arrangement is consistent with the geometric distribution of the Micro LED array, and each strip waveguide corresponds to a Micro LED light source; a nanostructure layer located on the optical waveguide layer, wherein the nanostructure layer includes a supercoupler and a waveguide-driven metasurface; The supercoupler is composed of a polarization-independent unit structure, which is used to couple the collimated light beam of the Micro LED vertically incident into the optical waveguide layer at a set angle to form a waveguide mode light; the waveguide-driven metasurface is used to decouple the waveguide mode light into free space to form a controllable light field.

2. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The unit structure of the supercoupler includes a cylinder or a square cylinder, whose size parameters are arranged through phase gradient, so that the vertically incident collimated light beam undergoes abnormal refraction and meets the waveguide total reflection condition, thereby realizing the coupling of free-space light to waveguide mode light.

3. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The supercoupler and Micro LED have a one-to-one correspondence, and each Micro LED is independently coupled to a corresponding strip waveguide channel. The strip waveguide channel is formed in the optical waveguide layer by etching to avoid crosstalk during light transmission.

4. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The unit structure of the waveguide-driven metasurface is designed through periodic displacement of nanocolumns and phase mutation, which extracts the waveguide mode light and superimposes the transmitted accumulated phase to achieve arbitrary wavefront control of the decoupled light field.

5. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The material refractive index of the optical waveguide layer is higher than that of the dielectric substrate layer and the air cladding layer, meeting the total reflection transmission condition of the guided wave mode light, and the waveguide thickness is limited to single-mode transmission.

6. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The nanocolumn structural parameters of the supercoupler and the waveguide driven supersurface are optimized by particle swarm algorithm or genetic algorithm to improve the coupling efficiency and decoupling accuracy of the target wavelength.

7. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The waveguide-driven metasurface and the supercoupler are separately arranged in the nanostructure layer and do not satisfy reciprocity, allowing only unidirectional coupling of free-space light through the supercoupler and unidirectional decoupling of guided-wave mode light through the waveguide-driven metasurface.

8. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The transmittance of the unit structure of the supercoupler is greater than a set threshold, and its phase library covers the range of 0 to 2π, and the light field distribution is verified by time-domain finite difference simulation.

9. The micro LED waveguide AR glasses on-chip integrated system according to claim 1, characterized in that: The decoupled light field of the waveguide-driven metasurface is used for holographic imaging or augmented reality display, and the light field control range covers the human eye's field of view.

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