CN218524914U - Optical waveguide system and near-eye display device - Google Patents

Abstract

The application discloses an optical waveguide system and a near-eye display device. The optical waveguide system comprises a waveguide substrate, a two-dimensional coupling-in grating, a folding grating and a coupling-out grating. The two-dimensional coupling-in grating conversion grating and the coupling-out grating are arranged on the waveguide substrate and are used for coupling the incident light into the optical waveguide. The incident light is diffracted by the two-dimensional coupling grating and then is divided into a first diffracted light beam with a first space vector K1 along the first direction and a second diffracted light beam with a second space vector Kn along other directions. The coupling grating is positioned on the first diffracted light beam propagation path, and the first diffracted light beam directly enters the coupling grating after being transmitted by the waveguide substrate. The deflecting grating is located on the propagation path of the second diffracted beam and is used for deflecting the second diffracted beam to emit the coupled-out grating. The folded grating has a space vector Km. The space vectors K1, kn and Km form a closed vector triangle. Through the mode, the transmission efficiency of coupled light is improved by the aid of the refraction grating.

Description

Optical waveguide system and near-eye display device

Technical Field

The present application relates to the field of optical imaging devices, and in particular, to optical waveguide systems and near-eye display devices.

Background

With the continuous development of the information age, people have higher and higher requirements on the performance of near-eye display equipment in production and life, and various novel display technologies emerge endlessly, wherein a display system utilizing the holographic waveguide technology is a research hotspot in the field of Augmented Reality (AR) at present. The holographic waveguide is an optical technology for realizing a large exit pupil and a large field of view by utilizing an incoupling grating, a waveguide material and an outcoupling grating, the technology combines the diffraction characteristic of the grating in a holographic recording material and the total reflection characteristic of light beams at the boundary of a waveguide medium, has smaller volume and lighter weight compared with a traditional optical system, is widely applied to a portable/head-mounted display terminal, and achieves certain achievements in the aspects of augmented reality and virtual reality display helmets in recent years.

In the holographic waveguide display structure, light beams can be diffracted out of a waveguide through a coupling-out grating and simultaneously can be totally reflected on the inner surface of a waveguide material, the times of the diffracted light are determined according to the size of the coupling-out grating and the size of an incident angle, the total reflection is generated, the light intensity incident on the coupling-out grating is sequentially weakened along with the increase of the diffraction times, if the diffraction efficiency of the coupling-out grating is certain, the phenomenon of uneven diffracted light can occur, and the brightness uniformity of the whole view field is poor.

SUMMERY OF THE UTILITY MODEL

The technical problem that this application mainly solved provides an optical waveguide system and near-eye display device, can improve the inhomogeneous problem of luminance of field of view.

In order to solve the technical problem, the application adopts a technical scheme that: there is provided an optical waveguide system comprising:

a waveguide substrate;

the two-dimensional incoupling grating is arranged on the waveguide substrate and used for incoupling incident light into the waveguide substrate, the incident light is diffracted by the two-dimensional incoupling grating and then is divided into a first diffracted light beam propagating along a first direction and a second diffracted light beam propagating along other directions, wherein the first diffracted light beam has a first space vector K1, and the second diffracted light beam has a second space vector Kn;

the coupling-out grating is arranged on the waveguide substrate and is positioned on a propagation path of the first diffracted light beam on the waveguide substrate, and the first diffracted light beam directly enters the coupling-out grating after being transmitted by the waveguide substrate;

the refraction grating is arranged on the waveguide substrate, is positioned on a propagation path of the second diffracted light beam on the waveguide substrate, and is used for refracting and converting the second diffracted light beam to the coupling-out grating, and the refraction grating has a space vector Km;

the space vectors K1, kn and Km of the first diffracted light beam, the second diffracted light beam and the refraction grating form a closed vector triangle.

In order to solve the technical problem, the application adopts a technical scheme that: the utility model provides a near-eye display device, includes the image source and the optical waveguide system that this application provided, the image source to optical waveguide system transmission light, optical waveguide system will the light is coupled out.

The beneficial effect of this application is: the optical waveguide system of the application comprises a waveguide substrate, a two-dimensional coupling-in grating, a folding grating and a coupling-out grating. The two-dimensional coupling grating is arranged on the waveguide substrate and used for coupling incident light into the optical waveguide, and the incident light is diffracted by the two-dimensional coupling grating and then is divided into a first diffracted light beam with a first space vector K1 and a second diffracted light beam with a second space vector Kn, which are transmitted along a first direction. The coupling grating is arranged on the waveguide substrate and is positioned on a propagation path of the first diffracted light beam on the waveguide substrate, and the first diffracted light beam directly enters the coupling grating after being transmitted by the waveguide substrate. The refraction grating is arranged on the waveguide substrate, is positioned on a propagation path of the second diffracted light beam on the waveguide substrate, and is used for refracting and deflecting the second diffracted light beam to the coupling-out grating. The folded grating has a space vector Km. The space vectors K1, kn and Km of the first diffracted light beam, the second diffracted light beam and the refraction grating form a closed vector triangle. Different from the prior art, the optical waveguide system of the application improves the utilization efficiency of light in the two-dimensional coupling grating coupling waveguide substrate and improves the whole energy utilization efficiency by arranging the turning grating on the waveguide substrate, so that the coupling light can enter a coupling-out area through a plurality of paths, and the problem of uneven brightness of a view field is solved.

Drawings

FIG. 1 is a schematic diagram of a near-eye display device according to an embodiment of the present application;

FIG. 2 is a schematic structural diagram of an embodiment of an optical waveguide system of the present application;

FIG. 3 is a schematic view of a light path on a waveguide substrate according to an embodiment of the present invention;

FIG. 4 is a schematic view of another propagation path of light at a waveguide substrate in an embodiment of an optical waveguide system of the present application;

FIG. 5 is a schematic view of another path of light propagating on a waveguide substrate in an embodiment of the optical waveguide system of the present application;

FIG. 6 is a schematic diagram of a grating vector of an embodiment of an optical waveguide system of the present application;

FIG. 7 is a schematic structural diagram of another embodiment of an optical waveguide system according to the present application;

fig. 8 is a schematic structural diagram of another embodiment of an optical waveguide system of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a near-eye display device according to an embodiment of the present application.

Near-eye display device 10 includes a wearing frame 11, a wearing frame 12, an image source 13, and an optical lens assembly 14. The wearing frame 12 is connected to the wearing frame 11. The image source 13 may also be referred to as a projector.

The wearing frame 11 has two window areas arranged at intervals, at least one of the two window areas is provided with an optical waveguide system 100, and the optical waveguide system 100 is the optical waveguide system provided by the present application.

The image source 13 is disposed at one side of the optical waveguide system 100 for generating light according to an image to be displayed. The optical lens assembly 14 is disposed between the image source 13 and the optical waveguide system 100, and is configured to inject the light into the optical waveguide system 100 according to a preset rule, and at least one of the image source 13 and the optical lens assembly 14 is disposed at a connection position where the wearing frame 11 is connected to the wearing frame 12.

It should be noted that the near-eye display device in the present application may include smart glasses, virtual reality smart glasses, and the like. It should be noted that the terms "comprises" and "comprising," and any variations thereof, in the embodiments of the present application, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or may alternatively include other steps or elements inherent to such process, method, article, or apparatus.

Referring to fig. 2, fig. 2 is a schematic structural diagram of an optical waveguide system according to an embodiment of the present application.

In the present application, the terms "first", "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present embodiment, the optical waveguide system 100 includes a waveguide substrate 110, a two-dimensional incoupling grating 120, a folding grating (not numbered), and an outcoupling grating 150.

The waveguide substrate 110 is a medium in which the guided light propagates, the light emits total reflection inside the waveguide substrate 110 for propagating the light of the light source to the human eye, and the waveguide substrate 110 may be a planar optical waveguide. Optionally, the waveguide substrate 110 is made of high-refractive-index glass, and the refractive index of the waveguide substrate 110 is greater than or equal to 1.7 and less than or equal to 2.3, which is beneficial to ensuring the high-refractive-index characteristic of the waveguide substrate 110, and the high refractive index can increase the size of the field angle, so as to implement an optical waveguide sheet with an ultra-large field angle. Of course, different materials can be selected according to actual requirements.

A two-dimensional incoupling grating 120 is disposed on the waveguide substrate 110 for coupling incident light of a light source into the waveguide substrate 110.

In the present embodiment, since the two-dimensional incoupling grating 120 is a two-dimensional grating, the two-dimensional incoupling grating 120 has a plurality of diffraction fields compared to a one-dimensional grating. In this embodiment, light coupled into the waveguide substrate 110 by the two-dimensional coupling grating 120 is diffracted by the two-dimensional coupling grating 120 and then divided into a first diffracted light beam L1 propagating along a first direction and a second diffracted light beam Ln propagating along other directions. Wherein the first diffracted light beam L1 has a first space vector K1, and the second diffracted light beam Ln has a second space vector Kn.

The coupling-out grating 150 is disposed on the waveguide substrate 110 and located on a propagation path of the waveguide substrate 110 where the first diffracted light beam L1 is located. Fig. 3 is a schematic diagram of a propagation path of a light ray at a waveguide substrate according to an embodiment of the present invention, and fig. 3 is a side view of fig. 2 relative to fig. 2, where the arrows indicate the general propagation path of the light ray and do not indicate the actual light path of the light ray.

The incident light is coupled into the waveguide substrate 110 by the two-dimensional coupling grating 120 to form a first diffracted light beam L1, which is transmitted in the waveguide substrate 110, is totally reflected and propagated in the waveguide substrate 110, is incident to directly enter the coupling grating 150, and is finally coupled out to the human eye by the coupling grating 150.

In the present embodiment, the coupling-out grating 150 is also a two-dimensional grating and has a plurality of diffraction fields, so that the coupling-out grating 150 not only functions to couple out light in the waveguide substrate 110, but also functions as a pupil expanding.

In the prior art, a method of setting a one-dimensional incoupling grating and a two-dimensional outcoupling grating is often used, and the diffraction directions of light incoupled by the one-dimensional incoupling grating are relatively concentrated, so that when relatively concentrated light enters the outcoupling grating, light emitted from the outcoupling grating will show a problem of middle bright stripes. In addition, the pupil expanding function of the coupling-out grating is limited, light rays of light waves incident on the coupling-out grating on the waveguide substrate are weakened along with the increase of diffraction times, the light rays emitted by the coupling-out grating are distributed unevenly, and the brightness of the central area of the coupled-out image is higher than that of the edge area of the coupled-out image.

In the embodiment, the two-dimensional incoupling grating 120 is disposed, and after the light is incoupled into the waveguide substrate 110 through the two-dimensional incoupling grating 120, light in multiple diffraction directions is generated. In order to couple out the light beams from the coupling-out grating 150, a turning grating is further disposed in the embodiment, the turning grating is located on a propagation path of the second diffracted light beam Ln, which is diffracted by the two-dimensional coupling-in grating 120 and propagates along other directions, on the waveguide substrate 110, and the turning grating can turn the second diffracted light beam Ln to the coupling-out grating 150, so that the light beams in different directions can be coupled out from the coupling-out grating 150, thereby improving the brightness of the edge area of the coupled-out image and improving the uniformity of the coupled-out image.

In order to meet the requirement that the deflecting grating can deflect the second diffracted light beam Ln to the coupled-out grating 150, the space vector Km of the deflecting grating should form a closed vector triangle with the first space vector K1 of the first diffracted light beam L1 and the second space vector Kn of the second diffracted light beam Ln.

The turning grating includes a first turning grating assembly 130 and a second turning grating assembly 140, and the first turning grating assembly 130 and the second turning grating assembly 140 are disposed on the waveguide substrate 110.

The first folding grating assembly 130 is located on the same side of the two-dimensional coupling grating 120 as the coupling grating, and the first folding grating assembly 130 is configured to fold and fold the second diffracted light beam Ln emitted to the outside of the coupling grating 150 to the coupling grating 150.

Referring to fig. 4, fig. 4 is a schematic diagram of another propagation path of a light ray on a waveguide substrate according to an embodiment of the present invention, in which arrows indicate the general propagation path of the light ray, and do not indicate the actual optical path of the light ray.

A part of the second diffracted light beam Ln1 diffracted by the two-dimensional coupling grating 120 and propagated in other directions propagates inside the waveguide substrate 110 to the first folding grating assembly 130, and after the second diffracted light beam Ln1 enters the first folding grating assembly 130, it is diffracted inside the first folding grating assembly 130, and then enters the waveguide substrate 110 again, and continues to propagate inside the waveguide substrate 110.

The first folding grating assembly 130 performs a folding function with respect to the second diffracted light beam Ln 1. The refracted light beam acted by the first refracted grating assembly 130 propagates inside the waveguide substrate 110, and is finally received by the coupling grating 150 and coupled out to human eyes.

Therefore, in the present embodiment, the first folding grating component 130 can fold a portion of the second diffracted light beam Ln1, which is diffracted by the two-dimensional incoupling grating 120 and propagates in other directions, and fold and convert the light to the outcoupling grating 150, so as to improve the energy of the light waves coupled out by the outcoupling grating 150 and increase the energy transfer efficiency of the optical waveguide system 100.

Referring to fig. 5, fig. 5 is a schematic diagram of another propagation path of light on a waveguide substrate according to an embodiment of the present invention, in which arrows indicate the general propagation path of light and do not indicate the actual optical path of light.

Specifically, a part of the second diffracted light beam Ln2, which is diffracted by the two-dimensional coupled-in grating 120 to propagate in the other direction, propagates inside the waveguide substrate 110 into the second folding grating assembly 140. After entering the second folding grating assembly 140, the light is emitted and diffracted inside the second folding grating assembly 140, and then enters the waveguide substrate 110 again, and continues to propagate inside the waveguide substrate 110. The second folding grating assembly 140 performs a folding function with respect to the second diffracted light beam Ln 2.

Therefore, in the embodiment, the first folding grating element 130 and the second folding grating element 140 can fold and convert more lights of other diffraction orders of the two-dimensional coupling grating 120, and fold and convert the lights to the coupling grating 150, so as to further improve the utilization efficiency of the coupled lights of the two-dimensional coupling grating 120, improve the energy of the light waves coupled out by the coupling grating 150, increase the energy transfer efficiency of the optical waveguide system 100, and improve the problem of uneven distribution of the coupled lights of the conventional optical waveguide.

Referring to fig. 2 and 6, fig. 6 is a schematic diagram of a grating vector according to an embodiment of the present invention.

Further, in the present embodiment, the second diffracted light beam Ln has the second space vector Kn including at least Kn1, kn2, kn3, kn4, kn5. Wherein the included angle between two adjacent vector directions of K1, kn2, kn3, kn4 and Kn5 is 60 degrees.

The first folding grating assembly 130 includes a first folding grating 131 having a space vector Km1 and a second folding grating 132 having a space vector Km2, and the first and second folding gratings 131 and 132 are diffraction gratings.

The first folding grating 131 and the second folding grating 132 are disposed at an interval on one side of the two-dimensional coupling-in grating 120 close to the coupling-out grating 150, and the first folding grating 131 and the second folding grating 132 are disposed on a propagation path of a portion of the second diffracted light beam Ln on the waveguide substrate 110, and perform a folding action on the light beams.

For example, the space vector Km1 of the first folding grating 131, the second space vector Kn1 of the second diffracted light beam Ln, and the first space vector K1 of the first diffracted light beam L1 form a closed vector triangle, so that the first folding grating 131 folds part of the second diffracted light beam Ln on the first space vector K1, so that these light beams can be folded to the coupling-out grating 150.

The space vector Km2 of the second turning grating 132, the second space vector Kn2 of the second diffracted light beam Ln, and the first space vector K1 of the first diffracted light beam L1 form a closed vector triangle, so that the second turning grating 132 turns a part of the second diffracted light beam Ln on the first space vector K1, and these light beams can be turned to the coupling grating 150.

The second folding grating assembly 140 includes a third folding grating 141 and a fourth folding grating 142, and the third folding grating 141 and the fourth folding grating 142 are diffraction gratings.

The third turning grating 141 and the fourth turning grating 142 are adjacently disposed on a side of the two-dimensional incoupling grating 120 away from the outcoupling grating 150, and the third turning grating 141 and the fourth turning grating 142 are disposed on a propagation path of a part of the second diffracted light beam Ln on the waveguide substrate 110, and perform a turning action on the light beams.

For example, three of the space vector Km3 of the third folding grating 141, the second space vector Kn3 of the second diffracted light beam Ln, and the first space vector K1 of the first diffracted light beam L1 form a closed vector triangle, so that the third folding grating 141 folds part of the second diffracted light beam Ln on the first space vector K1, so that these light beams can be folded to the coupling-out grating 150.

The space vector Km4 of the fourth turning grating 142, the second space vector Kn4 of the second diffracted light beam Ln, and the first space vector K1 of the first diffracted light beam L1 form a closed vector triangle, so that the fourth turning grating 142 turns a part of the second diffracted light beam Ln on the first space vector K1, and these light rays can be turned to the coupling grating 150.

Alternatively, the second space vector Kn5 of the second diffracted light beam Ln opposite to the first space vector K may form a closed vector triangle with three of the space vector Km3 of the third folding grating 141 and the space vector Km1 of the first folding grating 131, or form a closed vector triangle with three of the space vector Km4 of the fourth folding grating 142 and the space vector Km2 of the second folding grating 132, so that the light in the second space vector Kn5 direction can be refracted by the third folding grating 141 and the first folding grating 131, or by the fourth folding grating 142 and the second folding grating 132 and then enter the outcoupling grating 150.

Further, the first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 are one-dimensional gratings, and the one-dimensional gratings may be one or more of blazed gratings, tilted gratings, rectangular gratings, double-ridge gratings, and multi-layer gratings.

The first turning grating 131, the second turning grating 132, the third turning grating 141 and the fourth turning grating 142 transmit the corresponding coupled light in a one-dimensional direction, and transmit the coupled light in a pupil-expanding direction.

Based on the vector distribution of the gratings, grating size parameters of the two-dimensional incoupling grating 120, the outcoupling grating 150, the first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 are designed.

Optionally, the height of the two-dimensional incoupling grating 120 is greater than 50nm and less than or equal to 500nm, the duty ratio is greater than or equal to 30% and less than or equal to 80%, and the period is greater than or equal to 300nm and less than or equal to 600nm.

Optionally, the height of the outcoupling grating 150 is greater than 30nm and less than or equal to 300nm, the duty ratio is greater than or equal to 30% and less than or equal to 80%, and the period is greater than or equal to 300nm and less than or equal to 600nm.

Optionally, the height of each of the first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 is greater than 30nm and less than or equal to 300nm, the duty ratio is greater than or equal to 30% and less than or equal to 80%, and the period is greater than or equal to 250nm and less than or equal to 600nm.

The duty ratio, height and period of each grating are controlled within a reasonable range, so that the coupling-out efficiency of the coupling-out grating 150 is improved, and the specific parameters can be adjusted according to actual conditions, so that the uniformity of the coupled-out light intensity meets specific requirements.

In this embodiment, the first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 can fold light in 5 grating vector directions of the two-dimensional coupling grating 120, which are not in the direction of the coupling grating 150, so that the light in these directions can be coupled out from the coupling grating 150, the light wave energy of the coupling grating 150 is increased, the brightness of the coupling light of the coupling grating 150 is improved, and the problem of non-uniformity of the coupling light is compensated.

Referring to fig. 7, fig. 7 is a schematic structural diagram of an optical waveguide system according to another embodiment of the present application.

In this embodiment, the two-dimensional incoupling grating 120 is a circular grating, the first folding grating 131, the third folding grating 141 and the fourth folding grating 142 are parallelogram gratings, and the second folding grating 132 is a trapezoid grating.

In other embodiments, the two-dimensional incoupling grating 120, the outcoupling grating 150, the first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 may be any one of rectangles, diamonds, circles, or other polygons, and those skilled in the art may arbitrarily set according to practical situations.

Referring to fig. 8, fig. 8 is a schematic structural diagram of an optical waveguide system according to another embodiment of the present application.

In this embodiment, the outcoupling grating 150 is a rectangular grating, and the two-dimensional incoupling grating 120 is opposite to a certain corner of the rectangular grating, i.e. the outcoupling grating 150 and the two-dimensional incoupling grating 120 are obliquely arranged opposite to each other.

The first folding grating 131, the second folding grating 132, the third folding grating 141, and the fourth folding grating 142 are arranged in a manner and function similar to the above embodiments, and can also fold the light coupled into the two-dimensional grating 120 by a portion of the diffraction field, so that the light can be coupled out from the coupling grating 150.

In summary, the present application provides an optical waveguide system and an embodiment of a near-eye display device, in which the optical waveguide system couples light coupled into a waveguide substrate by a plurality of turning gratings, and the light can be coupled out from a coupling grating, thereby improving the utilization efficiency of the coupled light, compensating a darker coupled pattern area, making the coupled image clearer, and improving the imaging quality.

In further embodiments, a fifth, a sixth, and so on of more turning gratings may be further added to turn some light rays that cannot propagate to the coupling-out grating, so that the light rays can be coupled out from the coupling-out grating, and the number of the turning gratings is not limited herein.

In the description of the present application, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like is intended to mean that a particular feature, mechanism, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, mechanisms, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Moreover, various embodiments or examples and features of various embodiments or examples described in this specification can be combined and combined by one skilled in the art without being mutually inconsistent.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.

Claims (10)

1. An optical waveguide system, comprising:

a waveguide substrate;

the two-dimensional incoupling grating is arranged on the waveguide substrate and used for incoupling incident light into the waveguide substrate, the incident light is diffracted by the two-dimensional incoupling grating and then is divided into a first diffracted light beam propagating along a first direction and a second diffracted light beam propagating along other directions, wherein the first diffracted light beam has a first space vector K1, and the second diffracted light beam has a second space vector Kn;

the coupling-out grating is arranged on the waveguide substrate and is positioned on a propagation path of the first diffracted light beam on the waveguide substrate, and the first diffracted light beam directly enters the coupling-out grating after being transmitted by the waveguide substrate;

the refraction grating is arranged on the waveguide substrate, is positioned on a propagation path of the second diffracted light beam on the waveguide substrate, and is used for refracting and deflecting the second diffracted light beam to the coupling-out grating, and the refraction grating has a space vector Km;

the space vectors K1, kn and Km of the first diffracted light beam, the second diffracted light beam and the refraction grating form a closed vector triangle.

2. The optical waveguide system of claim 1,

the refraction grating comprises a first refraction grating component and a second refraction grating component, the first refraction grating component and the coupling grating are positioned on the same side of the two-dimensional coupling grating, the first refraction grating component is used for refracting and converting the second diffraction beam which is emitted to the outside of the range of the coupling grating to the coupling grating, the second refraction grating component and the coupling grating are positioned on the opposite sides of the two-dimensional coupling grating, and the second refraction grating component is used for refracting and converting the second diffraction beam which is emitted in the direction deviating from the direction of the coupling grating to the coupling grating.

3. The optical waveguide system of claim 2,

the first folding grating component comprises a first folding grating with a space vector Km1 and a second folding grating with a space vector Km2, the first folding grating and the second folding grating are arranged on one side, close to the coupling grating, of the two-dimensional coupling grating at intervals, the first folding grating is used for folding the second diffraction beam which is emitted to the outside of the range of the coupling grating and correspondingly has a space vector Kn1 to the coupling grating, and the second folding grating is used for folding the second diffraction beam which is emitted to the outside of the range of the coupling grating and correspondingly has a space vector Kn2 to the coupling grating;

the space vectors K1, kn1 and Km1 form a closed vector triangle, and the space vectors K1, kn2 and Km2 form a closed vector triangle.

4. The optical waveguide system of claim 3,

the second turning grating component comprises a third turning grating with a space vector Km3 and a fourth turning grating with a space vector Km4, the third turning grating and the fourth turning grating are adjacently arranged on one side, away from the coupling grating, of the two-dimensional coupling grating, the first turning grating is used for turning the second diffraction beam which is emitted to the outside of the range of the coupling grating and correspondingly has a space vector Kn3 to the coupling grating, and the second turning grating is used for turning the second diffraction beam which is emitted to the outside of the range of the coupling grating and correspondingly has a space vector Kn4 to the coupling grating;

the space vectors K1, kn3 and Km3 form a closed vector triangle, and the space vectors K1, kn4 and Km4 form a closed vector triangle.

5. The optical waveguide system of claim 4,

the heights of the first, second, third and fourth refraction gratings are greater than 30nm and less than or equal to 300nm, the duty ratio is greater than or equal to 30% and less than or equal to 80%, and the period is greater than or equal to 250nm and less than or equal to 600nm.

6. The optical waveguide system of claim 4,

the first, second, third and fourth folded gratings are one-dimensional gratings, and the one-dimensional gratings are one or more of blazed gratings, tilted gratings, rectangular gratings, double-ridge gratings and multi-layer gratings.

7. The optical waveguide system of claim 1,

the height of the two-dimensional coupling-in grating is larger than 50nm and smaller than or equal to 500nm, the duty ratio is larger than or equal to 30% and smaller than or equal to 80%, and the period is larger than or equal to 300nm and smaller than or equal to 600nm.

8. The optical waveguide system of claim 1,

the height of the coupled-out grating is greater than 30nm and less than or equal to 300nm, the duty ratio is greater than or equal to 30% and less than or equal to 80%, and the period is greater than or equal to 300nm and less than or equal to 600nm.

9. The optical waveguide system of claim 1,

the light coupling grating is a rectangular grating, and the two-dimensional light coupling grating is opposite to the corner of the rectangular grating.

10. A near-eye display device comprising an image source and an optical waveguide system as claimed in any one of claims 1 to 9, the image source emitting light into the optical waveguide system, the optical waveguide system coupling out the light.

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