WO2024108829A1 - Meta-structured and topological optical waveguide and augmented reality display device - Google Patents

Abstract

A meta-structured and topological optical waveguide, comprising a waveguide substrate (10). The waveguide substrate (10) is provided with a meta-structured coupling-in area (20) and a topological coupling-out area (30); the meta-structured coupling-in area (20) is provided with a coupling-in grating (21) located on the surface of the waveguide substrate (10) and a metamaterial layer (22) covering the coupling-in grating (21); and the topological coupling-out area (30) is provided with a coupling-out grating, the coupling-out grating comprises a plurality of rows of grating units (31) having a coupling effect, and the forms of the grating units (31) in the respective rows are different. By means of the structure, the meta-structured and topological optical waveguide can improve the overall light energy utilization rate, can improve the light conduction efficiency and the coupling-out efficiency, and has high coupling uniformity. Also provided is an augmented reality display device comprising the meta-structured and topological optical waveguide.

Description

Super-structured topological optical waveguide and augmented reality display device Technical Field

The present invention relates to the field of augmented reality display technology, and in particular to a metamorphic topological optical waveguide and an augmented reality display device.

Background technique

Augmented Reality (AR) technology is a new technology that "seamlessly" integrates real-world information and virtual-world information. It not only displays real-world information, but also displays virtual information at the same time. The two types of information complement and overlap each other. In visual augmented reality, users use helmet displays to overlap the real world with computer graphics, so they can see the real world around them.

Optical waveguides (also referred to as "light waveguides") have a wide range of applications in the field of augmented reality due to their total reflection optical properties, ultra-thin, and surface-machinable structures. Augmented reality display based on optical waveguides has become the mainstream display technology in the industry. For example, HoloLens developed by Microsoft has a large field of view augmented reality display based on a butterfly-shaped pupil dilation conduction display window; the augmented reality glasses developed by Magic Leap in the United States are based on a secondary unidirectional conduction optical waveguide design, and a combination of multiple pieces achieves color display.

In addition to being used in the field of near-eye display, augmented reality display based on optical waveguide can also be used in vehicle-mounted head-up display. At present, the mainstream head-up display is based on the principle of geometric optical space reflection, and has disadvantages such as large front-mounted volume, short virtual image viewing distance, and narrow eye movement range. Augmented reality head-up display based on optical waveguide can achieve advantages such as small front-mounted volume, long virtual image viewing distance, large eye movement range, and large field of view by increasing the surface area of the optical waveguide. It is a key display technology for intelligent driving and human-vehicle interaction.

technical problem

Most of the current augmented reality display technologies based on optical waveguides use the transmission concept of nanostructure diffraction, which results in a lot of waste in the process of light transmission, resulting in low overall coupling efficiency and low uniformity in the coupling range.

Technical Solutions

The object of the present invention is to provide a super-structured topological optical waveguide which can improve the overall light energy utilization rate, improve the light transmission efficiency and the outcoupling efficiency, and has high outcoupling uniformity.

The present invention provides a metastructure topological optical waveguide, comprising a waveguide substrate, on which a metastructure in-coupling region and a topological out-coupling region are provided; the metastructure in-coupling region is provided with an in-coupling grating located on the surface of the waveguide substrate and a metamaterial layer covering the in-coupling grating; the topological out-coupling region is provided with an out-coupling grating, and the out-coupling grating includes a plurality of rows of grating units having a coupling effect, and the grating units in each row have different morphologies.

Furthermore, the metamaterial layer is a metal film layer.

Furthermore, the refractive index of the metamaterial layer is greater than 1.5.

Furthermore, the thickness of the metamaterial layer is greater than or equal to 100 nanometers.

Furthermore, the incident angle range of the light in the coupling-in region of the metastructure is -20 degrees to 20 degrees.

Furthermore, the coupling-in grating and the coupling-out grating are located on the same side surface of the waveguide substrate; and the coupling-in region of the metastructure couples light by means of transmission coupling or reflection coupling.

Furthermore, the grating unit is a nano dot matrix structure, each row of the grating unit includes a plurality of nano grating dots, and the nano grating dots in the same row have the same structure, while the nano grating dots in different rows have different structures.

Furthermore, the grating unit is a nano dot matrix structure, each row of the grating unit includes a plurality of nano grating dots, and the structure of each of the nano grating dots is different.

Furthermore, each row of the grating units extends along the x-direction of the waveguide substrate; a plurality of rows of the grating units form a two-dimensional array grating, the nano-grating points of the plurality of rows of the grating units are periodically arranged, and have a first grating orientation M and a second grating orientation N that are cross-arranged, and the angle between the first grating orientation M and the second grating orientation N is 20º to 160º.

Furthermore, the metastructure coupling-in region and the topological coupling-out region are both rectangular and their width and length directions are consistent with those of the waveguide substrate, and the center lines of the metastructure coupling-in region and the topological coupling-out region coincide with each other in the y direction.

Furthermore, the morphology of the grating unit includes the shape, width, and height of each of the nano-grating points in each row of the grating units; the out-coupling conduction efficiency of the nano-grating points in the y direction increases with distance from the superstructure coupling-in region to the direction away from the superstructure coupling-in region.

The present invention also provides an augmented reality display device, comprising the above-mentioned metamorphic topological optical waveguide.

Beneficial Effects

The meta-morphological topological optical waveguide provided by the present invention utilizes coupling gratings and metamaterial layers to improve the overall light energy utilization rate, produce high coupling conduction efficiency, and then greatly improve the whole-surface coupling efficiency; cooperate with the grating units with different shapes in the topological coupling area to control the whole-surface coupling uniformity point by point, effectively improve the uneven light output phenomenon, and have high coupling uniformity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of a superstructure topological optical waveguide according to a preferred embodiment of the present invention;

FIG2 is a schematic diagram of the structure of the superstructure coupling region of a preferred embodiment of the present invention;

FIG3 is a schematic diagram of a combination of image light source incident on a meta-morphological topological optical waveguide and human eye observation in a preferred embodiment of the present invention;

FIG4 is a schematic diagram of positive and negative first-order diffraction efficiencies when no metamaterial layer is provided in the coupling-in region of the metastructure;

FIG5 is a simulation efficiency diagram of the superstructure coupling region shown in FIG3;

FIG6 is a schematic diagram showing the effect of the thickness of a metamaterial layer on diffraction efficiency;

FIG7 is a schematic diagram showing the effect of the incident angle of light on the diffraction efficiency in the coupling-in region of the metastructure;

FIG8 is a schematic diagram showing the effect of the incident azimuth angle of light on the diffraction efficiency in the coupling-in region of the metastructure;

FIG9 is a schematic diagram of another combination of image light source incident on a meta-morphological topological optical waveguide and human eye observation in a preferred embodiment of the present invention;

FIG10 a is a simulation efficiency diagram when no metamaterial layer is provided in the coupling-in region of the metastructure shown in FIG9 ;

FIG10 b is a simulation efficiency diagram of the superstructure coupling region shown in FIG9 ;

FIG11 is a schematic structural diagram of a topological outcoupling region of a metamorphic topological optical waveguide according to a preferred embodiment of the present invention;

FIG12 is a schematic diagram of the conduction process of light in the topological outcoupling region of the metamorphic topological optical waveguide in a preferred embodiment of the present invention;

FIG13 is a schematic structural diagram of a topological outcoupling region of a metamorphic topological optical waveguide according to a preferred embodiment of the present invention;

FIG14 is a schematic diagram of light transmission of a superstructure topological optical waveguide according to a preferred embodiment of the present invention;

FIG15 is a schematic diagram of light transmission of a conventional optical waveguide;

FIG16 is a schematic diagram of structural points within the outcoupling range of a superstructure topological optical waveguide according to a preferred embodiment of the present invention;

FIG17 is a trend diagram showing the variation of the out-coupling efficiency with depth and duty cycle within the out-coupling range of the meta-morphological topological optical waveguide in a preferred embodiment of the present invention.

Embodiments of the present invention

The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Figure 1 is a schematic diagram of the structure of a metastructure topological optical waveguide according to a preferred embodiment of the present invention. Please refer to Figure 1. The metastructure topological optical waveguide according to a preferred embodiment of the present invention includes a waveguide substrate 10, and a metastructure coupling-in region 20 and a topological coupling-out region 30 are provided on the waveguide substrate 10.

The waveguide substrate 10 has high transmittance in the visible light wavelength range and can be made of materials such as glass and resin.

2 is a schematic diagram of the structure of a metastructure coupling region of a preferred embodiment of the present invention. The metastructure coupling region 20 is provided with a coupling grating 21 located on the surface of the waveguide substrate 10 and a metamaterial layer 22 covering the coupling grating 21. The coupling grating 21 and the metamaterial layer 22 are used to couple light and at the same time efficiently improve the light transmitted in the waveguide substrate 10.

The coupling-in grating 21 is preferably a nanowire structure. The nanowire structure is a linear structure, which can be a regular rectangle or an irregular shape, and is arranged in a periodic manner.

The x direction is defined as the width direction of the waveguide substrate 10 in the figure, the y direction is defined as the length direction of the waveguide substrate 10 in the figure, and the z direction is defined as the thickness direction of the waveguide substrate 10. In this embodiment, the coupling grating 21 has a grating orientation (i.e., the channel direction of the grating). In this embodiment, the grating orientation of the coupling grating 21 is consistent with the x direction, i.e., consistent with the width direction of the waveguide substrate 10.

The metamaterial layer 22 is, for example, a metal film layer, such as aluminum, titanium dioxide, etc. The metamaterial layer 22 is meanderingly covered on the surface of the coupling-in grating 21. In this embodiment, the refractive index of the metamaterial layer 22 is greater than 1.5. When the incident light is incident on the metastructure coupling-in region 20 and diffracted, the diffracted light includes zero-order diffraction light, negative first-order diffraction light, and positive first-order diffraction light. As shown in FIG2 , after the light passes through the metamaterial layer 22, the diffraction efficiency of the positive and negative first-order diffraction light is greatly improved, and has basically reached the diffraction efficiency of the zero-order diffraction light. The metamaterial layer 22 can improve the diffraction efficiency of the positive and negative first-order diffraction light, thereby greatly improving the conduction efficiency.

FIG3 is a schematic diagram of a combination of incident image light source and human eye observation of a meta-structure topological optical waveguide in a preferred embodiment of the present invention. Please refer to FIG3. In the embodiment of the present invention, the coupling-in grating 21 and the coupling-out grating are located on the same side surface of the waveguide substrate 10, but the invention is not limited thereto. The image light source 40 can be incident from the structural surface of the meta-structure topological optical waveguide (the surface with the coupling-in grating 21 and the coupling-out grating), and the meta-structure coupling-in region 20 adopts a transmission coupling method for light coupling, and the human eye 50 also observes from the structural surface.

FIG4 is a schematic diagram of the positive and negative first-order diffraction efficiencies when the metamaterial layer is not provided in the metastructure coupling region. As shown in FIG4 , if the metastructure coupling region 20 is only provided with a coupling grating 21 (without the metamaterial layer 22), the diffraction efficiency of the positive and negative first-order diffraction light is very low at a specific wavelength due to the diffraction efficiency limited by the physical essential characteristics.

FIG5 is a simulation efficiency diagram of the metastructure coupling region shown in FIG3 . It can be seen from FIG5 that after the light is coupled into the metastructure coupling region 20 having the metamaterial layer 22 , the transmission efficiency of the positive and negative first-order diffraction light is greater than 30%.

FIG6 is a schematic diagram of the effect of the thickness of the metamaterial layer on the diffraction efficiency. As shown in FIG6 , it can be seen that the thickness of the metamaterial layer 22 has a sudden change above 100 nanometers (nm), and the diffraction efficiency of the metastructure coupling region 22 is directly increased from a very low value to between 20% and 30%, and then with the increase of depth, its diffraction efficiency is stabilized in this range. In other words, the thickness of the metamaterial layer 22 is preferably greater than or equal to 100 nanometers.

FIG7 is a schematic diagram showing the effect of the incident angle of light in the meta-structure coupling region on the diffraction efficiency. As shown in FIG7 , within the range of incident angle of plus or minus 20 degrees, the diffraction efficiency of the meta-structure coupling region 22 is relatively balanced, indicating that it has good angle tolerance and supports field display within this range. In other words, the incident angle range of the light (i.e., the light emitted by the image light source 40) in the meta-structure coupling region 20 is preferably -20 degrees to 20 degrees.

Figure 8 is a schematic diagram of the effect of the incident azimuth angle of light in the metastructure coupling region on the diffraction efficiency. As shown in Figure 8, as the azimuth angle changes from 0 degrees to 360 degrees, it can be seen that the change in efficiency is consistently between 20% and 40%. That is to say, no matter from which azimuth angle the image light source 40 is incident, the effect on the diffraction efficiency of the metastructure coupling region 20 is not very large, and the metastructure coupling region 20 has a wide azimuth angle tolerance.

In another embodiment of the present invention, the incident light may also be on a different side from the observation direction. Specifically, FIG9 is a schematic diagram of another combination of the image light source incident on the metastructure topological optical waveguide and the human eye observation of a preferred embodiment of the present invention, as shown in FIG9 , wherein the coupling grating 21 and the coupling out grating are located on the same side surface of the waveguide substrate 10, when the image light source 40 is incident on the metastructure coupling region 20 from the non-structure surface (the side without the coupling grating 21) of the metastructure topological optical waveguide, the light is reflectively diffracted by the metastructure coupling region 20, that is, the metastructure coupling region 20 couples the light by reflective coupling, generates the conducted light, and the human eye 50 can observe from the structure surface.

FIG10a is a simulation efficiency diagram when no metamaterial layer is set in the metastructure coupling region shown in FIG9 , and FIG10b is a simulation efficiency diagram of the metastructure coupling region shown in FIG9 . Please refer to FIG10a and FIG10b together. Light is coupled in the metastructure coupling region 20 in the reflective coupling manner shown in FIG9 . At an incident wavelength of 520 nm, the coupling grating 21 is a pure nanostructure, with a period of 433 nm, a duty cycle of 0.7, and a depth of 230 nm. When the metamaterial layer 22 is not set in FIG10a , the reflective first-order diffraction efficiency is low. When the metamaterial layer 22 (such as a thickness of 40 nm) is set in FIG10b , the reflective first-order diffraction efficiency can be increased to 30% compared with FIG10a , which can be nearly 3 times higher than when the metamaterial layer 22 is not set.

The topological outcoupling region 30 is used to outcouple light. The topological outcoupling region 30 is provided with an outcoupling grating, which includes multiple rows of grating units 31 with coupling effect, and each row of grating units 31 has different shapes, specifically different structural parameters such as shape, width, height, etc.

The grating unit 31 may be a nanowire structure or a nano dot lattice structure. The nanowire structure is a linear structure, which may be a regular rectangle or an irregular shape, arranged periodically. A single unit of the nano dot lattice structure may be any regular or irregular shape such as a cylinder, a square column, a trapezoidal column, etc., and may also be arranged periodically. It may be prepared by holographic interference technology, photolithography technology or nanoimprint technology. The grating unit 31 is preferably a nano dot lattice structure.

Fig. 11 is a schematic diagram of the topological outcoupling region of the metamorphic topological optical waveguide of a preferred embodiment of the present invention, in which each row of grating units 31 is a nano dot matrix structure. Each row of grating units 31 includes a plurality of nano grating dots 311, and the structures of the nano grating dots 311 in the same row are the same. Since the structures of the grating units 31 in each row are different, the structures of the nano grating dots 311 in different rows are different.

In another embodiment of the present invention, the structure of each nano-grating dot 311 in the topological outcoupling region 30 is different, that is, not only the structures of the nano-grating dots 311 in different rows are different, but also the structures of the nano-grating dots 311 in the same row are different. It can also be understood that there are as many types of outcoupling gratings as there are nano-grating dots 311.

Furthermore, each row of grating units 31 extends along the x direction (i.e., the width direction) of the waveguide substrate 10. The multiple rows of grating units 31 form a two-dimensional array grating, and the nano-grating points 311 of the multiple rows of grating units 31 are arranged in a periodic arrangement and have a first grating orientation M and a second grating orientation N that are arranged crosswise.

Further, the angle between the first grating orientation M and the second grating orientation N is 20° to 160°. For example, the x direction of the first grating orientation M forms an angle of 120°, and the second grating orientation N forms an angle of 60° with the x direction.

The shape of the metastructure coupling-in region 20 and the topological coupling-out region 30 can be circular, rectangular, conical or other shapes adapted to the waveguide substrate 10. In this embodiment, the metastructure coupling-in region 20 and the topological coupling-out region 30 are both rectangular and the width and length directions are consistent with those of the waveguide substrate 10, and the center lines of the metastructure coupling-in region 20 and the topological coupling-out region 30 in the y direction coincide.

FIG12 is a schematic diagram of the conduction process of light in the topological out-coupling area of the meta-structure topological optical waveguide of a preferred embodiment of the present invention. Please refer to FIG11 and FIG12 together. After the image light is coupled into the meta-structure coupling-in area 20, it is conducted toward the topological out-coupling area 30. The light propagates in the topological out-coupling area 30 from the direction close to the meta-structure coupling-in area 20 to the direction away from the meta-structure coupling-in area 20. The out-coupling grating of the topological out-coupling area 30 is a nano dot matrix structure. The light transmitted through the coupling is obliquely entered into each row of grating units 31 at a certain angle. Each nano-grating point 31 in each row of grating units 31 has multi-directional diffusion of light in the optical waveguide, including coupling to the left, coupling to the right and coupling in the center. During the out-coupling conduction process of each nano-grating point 31, the light and the nano-grating point 311 are similar to the "topological" structure. The light continuously diffuses in multiple directions in the set direction, realizing the function of conducting while expanding the pupil.

Since the structures of the nano-grating dots 311 in each row of grating units 31 are different, by adjusting the structures of the nano-grating dots 311 in each row of grating units 31, the total energy of the outcoupled light from each row of nano-grating dots 311 can be adjusted to ensure the uniformity of light output in the entire outcoupled range.

Specifically, Fig. 13 is a schematic diagram of the topological out-coupling region of the meta-structure topological optical waveguide of the preferred embodiment of the present invention. Please refer to Fig. 13. In the entire topological out-coupling region 30, in order to meet the purpose of point-by-point efficiency control, the morphology of each row of grating units 31 is optimized and regulated, specifically including the morphology of each nano-grating point 311 in each row of grating units 31, including parameters such as shape, width, and height, so that the structure of the nano-grating points 311 in each row of grating units 31 is different, and finally the out-coupling conduction efficiency of the nano-grating points 311 in the direction from the meta-structure coupling-in region 20 to the direction away from the meta-structure coupling-in region 20 in the y direction increases with the distance, that is, the farther the nano-grating points 311 are from the meta-structure coupling-in region 20, the higher the out-coupling conduction efficiency is, and the closer the nano-grating points 311 are to the meta-structure coupling-in region 20, the lower the out-coupling conduction efficiency is, and the incremental change can be uniform or non-uniform.

Fig. 14 is a schematic diagram of light transmission of a metamorphic topological optical waveguide according to a preferred embodiment of the present invention. It can be seen that, assuming that the topological structures at abc are designed differently, and the out-coupling transmission efficiency at c is greater than that at b, and the out-coupling transmission efficiency at b is greater than that at a. When the light passes through abc, its out-coupling efficiency can be controlled point by point, thereby achieving uniform out-coupling of the light in the z direction.

FIG15 is a schematic diagram of light conduction in an existing optical waveguide. When the structure of each row of grating units in the out-coupling region 30' is the same, it can be seen that the light is coupled in through the coupling-in region 20', regardless of whether the coupling-in region 20' is provided with a metamaterial layer 22, and is conducted in the waveguide. When passing through the out-coupling region 30', part of the light is coupled out, and part of the light continues to be conducted in the waveguide. However, it can be known that if the out-coupling structure is not point-by-point controlled, the total energy of the light coupled out in the z direction each time is reduced according to the distance, which will lead to the phenomenon of uneven efficiency of the out-coupling region (the conduction efficiency close to the coupling-in region 20' is high, and the conduction efficiency far from the coupling-in region 20' is low).

Fig. 16 is a schematic diagram of the structure points within the outcoupling range of the metamorphic topological optical waveguide of the preferred embodiment of the present invention. In fact, by controlling the parameters abcd in the figure (a is the grating period, b is the spacing between two adjacent nano-grating points 311, cd is the morphological parameters of the nano-grating point 311 (such as the short side and long side of the rectangular grating structure, when the nano-grating point 311 is other structures, the morphological parameters have different definitions)), point-by-point precise efficiency modulation can be achieved, thereby achieving uniformity of outcoupling efficiency.

FIG17 is a trend diagram of the coupling efficiency of the meta-morphology topological optical waveguide in the coupling range of the preferred embodiment of the present invention as the depth and duty cycle change. Among them, the period is set to 433nm, the incident wave is from 520nm, the long side duty cycle varies from 0.4 to 1.4, the short side is set to 0.6 times the long side size, and the depth varies from 10 to 800nm. It can be seen from the simulation diagram that by modulating the long side duty cycle or depth (i.e., the height of the nano-grating point 311), a large range of coupling efficiency changes can be achieved, thereby providing a method for accurately controlling uniformity.

The present invention also relates to an augmented reality display device, comprising the above-mentioned metamorphic topological optical waveguide. Other structures of the augmented reality display device are well known to those skilled in the art and will not be described in detail here.

Beneficial effects: The metastructure topological optical waveguide of the present invention is provided with a metastructure coupling-in region and a topological coupling-out region on the waveguide substrate; wherein the metastructure coupling-in region is provided with a coupling-in grating located on the surface of the waveguide substrate and a metamaterial layer covering the coupling-in grating; the topological coupling-out region is provided with a coupling-out grating, and the coupling-out grating includes multiple rows of grating units with coupling effects, and the grating units in each row have different shapes. The present invention utilizes the coupling-in grating and the metamaterial layer to improve the overall light energy utilization rate, generate high coupling-in conduction efficiency, and then greatly improve the whole-surface coupling-out efficiency; cooperate with the grating units with different shapes in the topological coupling-out region, control the whole-surface coupling-out uniformity point by point, effectively improve the light output unevenness phenomenon, and achieve high coupling-out uniformity.

In the drawings, the sizes and relative sizes of layers and regions are exaggerated for clarity. It should be understood that when an element, such as a layer, region, or substrate, is referred to as being "formed on," "disposed on," or "located on" another element, the element may be disposed directly on the other element, or there may be intervening elements. Conversely, when an element is referred to as being "formed directly on" or "disposed directly on" another element, there are no intervening elements.

In this document, unless otherwise specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

In this document, the directions or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "vertical", and "horizontal" are based on the directions or positional relationships shown in the accompanying drawings and are only for the clarity of expressing the technical solutions and the convenience of description, and therefore should not be understood as limitations of the present invention.

In this document, the ordinal adjectives “first”, “second”, etc. used to describe elements are only used to distinguish elements with similar attributes, and do not mean that the elements described in this way must follow a given order, or time, space, level or other limitations.

As used herein, unless otherwise specified, “plurality” or “several” means two or more.

In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (12)

1. A metastructure topological optical waveguide comprises a waveguide substrate (10), characterized in that a metastructure in-coupling region (20) and a topological out-coupling region (30) are provided on the waveguide substrate (10); the metastructure in-coupling region (20) is provided with an in-coupling grating (21) located on the surface of the waveguide substrate (10) and a metamaterial layer (22) covering the in-coupling grating (21); the topological out-coupling region (30) is provided with an out-coupling grating, the out-coupling grating comprising a plurality of rows of grating units (31) having a coupling effect, the grating units (31) in each row having a different morphology.
2. The metamorphic topological optical waveguide according to claim 1, characterized in that the metamaterial layer (22) is a metal film layer.
3. The metamorphic topological optical waveguide according to claim 1, characterized in that the refractive index of the metamaterial layer (22) is greater than 1.5.
4. The metamorphic topological optical waveguide according to claim 1, characterized in that the thickness of the metamaterial layer (22) is greater than or equal to 100 nanometers.
5. The metamorphic topological optical waveguide as claimed in claim 1 is characterized in that the incident angle range of the light in the metamorphic coupling-in region (20) is -20 degrees to 20 degrees.
6. The metastructure topological optical waveguide according to claim 1 is characterized in that the coupling-in grating (21) and the coupling-out grating are located on the same side surface of the waveguide substrate (10); and the metastructure coupling-in region (20) couples light by means of transmission coupling or reflection coupling.
7. The metamorphic topological optical waveguide according to claim 1, characterized in that the grating unit (31) is a nano dot matrix structure, each row of the grating units (31) comprises a plurality of nano grating dots (311), and the structures of the nano grating dots (311) in the same row are the same, while the structures of the nano grating dots (311) in different rows are different.
8. The metamorphic topological optical waveguide according to claim 1, characterized in that the grating unit (31) is a nano-dot matrix structure, each row of the grating units (31) includes a plurality of nano-grating dots (311), and the structure of each of the nano-grating dots (311) is different.
9. The metamorphic topological optical waveguide according to claim 7 or 8, characterized in that each row of the grating units (31) extends along the x-direction of the waveguide substrate (10); a plurality of rows of the grating units (31) form a two-dimensional array grating, the nano-grating points (311) of the plurality of rows of the grating units (31) are arranged in a periodic arrangement, and have a first grating orientation M and a second grating orientation N that are arranged in a cross-arrangement, and the angle between the first grating orientation M and the second grating orientation N is 20° to 160°.
10. The metastructure topological optical waveguide according to claim 7 or 8, characterized in that the metastructure coupling-in region (20) and the topological coupling-out region (30) are both rectangular and the width and length directions are consistent with those of the waveguide substrate (10), and the center lines of the metastructure coupling-in region (20) and the topological coupling-out region (30) in the y direction coincide with each other.
11. The metastructure topological optical waveguide according to claim 7 or 8, characterized in that the shape of the grating unit (31) includes the shape, width and height of each of the nano-grating points (311) in each row of the grating units (31); and the out-coupling conduction efficiency of the nano-grating points (311) in the y direction from the direction close to the metastructure coupling-in region (20) to the direction away from the metastructure coupling-in region (20) increases with the distance.
12. An augmented reality display device, characterized in that it comprises a metamorphic topological optical waveguide as described in any one of claims 1 to 11.