A grating waveguide device and a waveguide system for reducing moiré patterns

Abstract

The present invention provides a grating waveguide device and a waveguide system for reducing rainbow patterns. The grating waveguide device includes a waveguide substrate and a grating structure. The grating structure is disposed on the waveguide substrate. The grating structure receives a projection beam from an imaging device. The grating structure has a grating vector, and the grating vector modulates the projection beam to obtain a modulated beam. The modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate, and the propagation direction of the modulated beam inside the waveguide substrate satisfies the total reflection condition. The grating vector of the grating structure forms one and only one closed loop. On the one hand, it can ensure that when the projected image of the imaging device enters the eyebox through the grating structure of the waveguide substrate in the form of a projection beam, the imaging displayed by the grating waveguide device is distortion-free and aberration-free compared to the projected image of the imaging device. On the other hand, the diffracted light generated by the diffraction of ambient light through the grating structure does not enter the eyebox area, so that the human eye will not observe the rainbow pattern phenomenon inside the eyebox.

Description

Technical Field

[0001] The present invention belongs to the technical field of augmented reality, and particularly relates to a grating waveguide device and a waveguide system for reducing rainbow fringes. Background Art

[0002] Augmented Reality (AR) technology refers to providing additional information (i.e., the so-called "augmentation") for users in the real world through certain technical means. This technology organically combines the images of the virtual world and the scenes of the real world, and through deep integration of the calculated information with the real world, it provides users with richer information and immersive experiences.

[0003] Augmented reality technology can be implemented through many hardware platforms. Among them, the most immersive one is the wearable augmented reality device, that is, AR glasses. The hardware form of this method is a simple pair of glasses, which guides light into the human eye through the microstructures on the lens surface. This hardware implementation method is the most convenient and is the mainstream technology of AR. The purpose of the AR glasses lens is to guide the image from the imaging device into the human eye through the lens. The grating waveguide solution is a mainstream technical solution. The grating waveguide includes a waveguide substrate, an input grating, and an output grating. The input grating and the output grating are arranged on the waveguide substrate, and its basic principle is as Figure 1 shown. The light output by the optical engine 1 (imaging device) is coupled into the waveguide substrate 2 by the input grating 3, and propagates in the waveguide substrate 2 by total reflection. Whenever it encounters the output grating 4, a part of the light is coupled out, and the coupled-out light (the solid line in the direction of entering the human eye in the figure) enters the human eye, so that the same image as the output of the optical engine 1 can be seen. At the same time, the human eye can see the real-world scene (the dotted line in the direction of entering the human eye in the figure). The overlap of the two parts can achieve the function of augmented reality.

[0004] However, for the grating waveguide used as the AR glasses lens solution, when the user actually wears the AR glasses, in addition to observing the image output from the optical engine and coupled out by the grating waveguide within the eye box, the user can usually also observe the rainbow fringe phenomenon formed by the ambient light directly diffracted by the output grating into the eye box. The rainbow fringe, as an interfering background, seriously affects the imaging effect of the human eye on the image. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the present invention provides a grating waveguide device and a waveguide system for reducing rainbow fringes.

[0006] The present invention is realized through the following technical solutions:

[0007] The present invention provides a grating waveguide device for reducing rainbow patterns. The grating waveguide device includes a waveguide substrate and a grating structure; the grating structure is disposed on the waveguide substrate;

[0008] The grating structure receives a projection beam from an imaging device;

[0009] The grating structure has a grating vector, which modulates the projection beam to obtain a modulated beam. The modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate, and the propagation directions of the modulated beam inside the waveguide substrate all satisfy the total reflection condition;

[0010] The grating vectors of the grating structure form one and only one closed loop.

[0011] Further, the grating structure includes an input grating and an output grating;

[0012] The waveguide substrate is provided with the input grating and the output grating on the same plane or different planes;

[0013] The input grating adopts a one-dimensional grating, a two-dimensional grating or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating;

[0014] The output grating adopts a two-dimensional grating or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0015] Further, the two-dimensional grating adopts a single two-dimensional grating or a partitioned combined grating of at least two two-dimensional gratings.

[0016] Further, the grating structure includes an input grating, a turning grating and an output grating;

[0017] The turning grating and the output grating are located on different planes and are arranged in parallel;

[0018] The input grating adopts a one-dimensional grating, a two-dimensional grating or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating;

[0019] The turning grating adopts a one-dimensional grating, a two-dimensional grating or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating;

[0020] The output grating adopts a one-dimensional grating, a two-dimensional grating or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating;

[0021] The grating line region of the turning grating and the grating line region of the output grating have an overlapping region in space.

[0022] Further, the grating vectors of the input grating and the output grating form one and only one closed loop in the K space.

[0023] Furthermore, the grating vectors of the input grating, the turning grating, and the output grating form exactly one closed loop in the K space.

[0024] Furthermore, the input grating has a grating vector The output grating has a grating vector and

[0025] In the K space, there is exactly one closed loop such that

[0026] Furthermore, the input grating has a grating vector The turning grating has a grating vector The output grating has a grating vector

[0027] In the K space, there is exactly one closed loop such that

[0028] Furthermore, by adjusting the grating period, the grating vectors of the grating structure form exactly one closed loop in the K space.

[0029] Furthermore, during the process of adjusting the grating period so that the grating vectors of the grating structure form exactly one closed loop in the K space, by adjusting the grating line direction, the projection beam of the imaging device can be completely displayed after being coupled out through the grating waveguide device and entering the human eye.

[0030] Furthermore, the grating region of the output grating is located above the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in a diagonally downward direction.

[0031] Furthermore, the overlapping region of the grating lines of the output grating and the turning grating is located above the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in a diagonally downward direction.

[0032] Furthermore, the grating region of the output grating is located below the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in a diagonally upward direction.

[0033] Furthermore, the overlapping region of the grating lines of the output grating and the turning grating is located below the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in a diagonally upward direction.

[0034] Furthermore, the grating region of the output grating is located in the pupil's horizontal viewing direction;

[0035] The projection beam enters the grating region of the input grating in a normal incidence direction.

[0036] Further, the overlapping region of the grating lines of the output grating and the turning grating is located in the direction of the pupil looking straight ahead;

[0037] The projection beam enters the grating region of the input grating in the normal incidence direction.

[0038] Further, the modulated beam obtained by modulating the ambient light by the grating vector is outside the region observable by the human eye.

[0039] The present invention also provides a waveguide system, including a grating waveguide device;

[0040] Wherein, the grating waveguide device adopts the grating waveguide device for reducing rainbow fringes as described above.

[0041] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0042] The present invention provides a grating waveguide device for reducing rainbow fringes. The grating waveguide device includes a waveguide substrate and a grating structure. The grating structure is disposed on the waveguide substrate. The grating structure receives the projection beam of the imaging device. The grating structure has a grating vector. The grating vector modulates the projection beam to obtain a modulated beam. The modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate. The propagation direction of the modulated beam inside the waveguide substrate all satisfies the total reflection condition. The grating vector of the grating structure forms one and only one closed loop. Forming one and only one closed loop for the grating vector of the grating structure, on the one hand, it can ensure that the FOV projected by the imaging device passes through the action of the grating vector of the grating structure of the waveguide substrate and finally returns to the original state, that is, when the projected image of the imaging device enters the eye box through the grating structure of the waveguide substrate in the form of a projection beam, the image displayed by the grating waveguide device is distortion-free and non-distorted compared with the projected image of the imaging device. On the other hand, the diffracted light of the ambient light diffracted by the grating structure will not enter the eye box region, so that the human eye can only observe the image output from the imaging device and coupled out by the grating waveguide device into the eye box within the eye box range, and will not observe the rainbow fringe phenomenon formed by the ambient light directly diffracted into the eye box by the grating structure, improving the viewing effect of the image output by the grating waveguide device by the human eye. Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0044] Figure 1This is a schematic diagram of the basic principle of the grating waveguide solution;

[0045] Figure 2 A schematic diagram of a grating vector for an example one-dimensional grating;

[0046] Figure 3 A schematic diagram of a grating vector of an example two-dimensional grating;

[0047] Figure 4a Schematic diagram of K space for light propagating in air;

[0048] Figure 4b Schematic diagram of K space for light propagating in a homogeneous medium with a refractive index of n;

[0049] Figure 5 Schematic diagram of the analysis of the k-vector effect of the grating waveguide on light;

[0050] Figure 6 Schematic diagram of the K-space in-plane component of an exemplary grating waveguide;

[0051] Figure 7 A schematic diagram of k-space design of an existing grating waveguide is shown as an example;

[0052] Figure 8 For Figure 7 The schematic diagram of k-space design of the existing grating waveguide is a schematic diagram of the real space light path transmission in the grating waveguide given as an example;

[0053] Figure 9a A schematic diagram of the formation principle of the rainbow pattern phenomenon when the existing grating waveguide is used as an AR glasses lens;

[0054] Figure 9b for Figure 9a Section diagram on the xz plane;

[0055] Figure 10 A first exemplary schematic diagram of a grating structure based on the concept of forming one and only one closed loop in the K space for all grating vectors of the grating structure according to the present invention;

[0056] Figure 11 A second exemplary schematic diagram of a grating structure based on the concept of forming one and only one closed loop in the K space for all grating vectors of the grating structure according to the present invention;

[0057] Figure 12 A third exemplary schematic diagram of a grating structure based on the concept of forming one and only one closed loop in the K space for all grating vectors of the grating structure according to the present invention;

[0058] Figure 13 Schematic diagram of k-space design of the grating waveguide of the present invention;

[0059] Figure 14 For the Figure 13 Schematic diagram of the real-space optical path conduction in the grating waveguide, which is exemplarily given for the k-space design of the grating waveguide of the exemplary present invention;

[0060] Figure 15 Exemplarily given based on Figure 13 Schematic diagram of the k-space design of the adjusted grating waveguide;

[0061] Figure 16 Exemplarily given based on Figure 15 Schematic diagram of the real-space optical path conduction in the grating waveguide, which is exemplarily given for the k-space design of the adjusted grating waveguide.

[0062] Wherein, 1-optical machine, 2-waveguide substrate, 3-coupling grating, 4-output grating, 5-turning grating. Detailed implementation manners

[0063] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0064] In this article, the terms "first", "second" and other similar words do not intend to imply any order, quantity and importance, but are only used to distinguish different elements. In this article, the terms "a", "an" and other similar words do not intend to mean that there is only one such thing, but mean that the relevant description is only directed to one of such things, and such things may have one or more. In this article, the terms "comprise", "include" and other similar words are intended to represent logical interrelationships and cannot be regarded as representing spatial structural relationships. For example, "A includes B" is intended to mean that logically B belongs to A, rather than meaning that B is located inside A in terms of space. In addition, the meanings of the terms "comprise", "include" and other similar words should be regarded as open rather than closed. For example, "A includes B" is intended to mean that B belongs to A, but B does not necessarily constitute all of A, and A may also include other elements such as C, D, E, etc.

[0065] In this document, the terms "embodiment", "this embodiment", "preferred embodiment", and "an embodiment" do not mean that the relevant description only applies to a specific embodiment, but rather that these descriptions may also apply to one or more other embodiments. Those skilled in the art should understand that in this document, any description made for a certain embodiment can be substituted, combined, or otherwise combined with the relevant descriptions in one or more other embodiments. The new embodiments generated by such substitution, combination, or other combination are easily conceivable by those skilled in the art and fall within the protection scope of the present invention.

[0066] In the description herein, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0067] Grating vector:

[0068] A grating has a grating vector. For example,

[0069] For a one-dimensional grating, such as Figure 2 shown, exemplarily, there is one grating vector. The magnitude of the grating vector is related to the grating period (K = 2π / d, where K represents the magnitude of the grating vector of the one-dimensional grating and d is the period of the one-dimensional grating). The direction of the grating vector is perpendicular to the grating line direction of the one-dimensional grating.

[0070] For a two-dimensional grating, such as Figure 3 shown, exemplarily, there are two grating vectors (the first grating vector and the second grating vector). The magnitude of the first grating vector is K1 = 2π / d1 / sin(a), and the magnitude of the second grating vector is K2 = 2π / d2 / sin(a). The direction of the first grating vector is perpendicular to the grating line direction of the second-dimensional grating (grating period is d2), and the direction of the second grating vector is perpendicular to the grating line direction of the first-dimensional grating (grating period is d1), where d1 is the grating period of the first-dimensional grating, d2 is the grating period of the second-dimensional grating, and a is the included angle between the grating line direction of the first-dimensional grating and the grating line direction of the second-dimensional grating.

[0071] To be consistent with the case of one-dimensional gratings, the magnitude K of the grating vector of two-dimensional gratings is usually defined as K = 2π / d eff , where K represents the magnitude of the grating vector, and d eff represents the magnitude of the grating period component in the direction of the grating vector. Exemplarily, the above K1 = 2π / d1 / sin(a) = 2π / d1 eff , K2 = 2π / d2 / sin(a) = 2π / d2 eff .

[0072] Unless otherwise specified, the grating period in the grating vector magnitude formula of the two-dimensional grating mentioned below is the magnitude of the grating period component in the grating vector direction.

[0073] K-space representation of light propagating in a homogeneous medium:

[0074] For light propagating in a homogeneous medium, its propagation behavior can usually be abstracted into k-space for representation and analysis. The magnitude of the k-vector reflects the propagation speed of light in the homogeneous medium, and the direction of the k-vector usually represents the propagation direction of light. For light propagating in vacuum (or air), the magnitude of its k-vector is Here, λ0 is the wavelength of light in vacuum (or air). For light with wavelength λ0, if is used to represent the propagation state of light in air, then all possible propagation states of light form a sphere in k-space with k0 (the magnitude of k0 is ) as the radius, as shown in Figure 4a . In the figure, K x represents the unit vector of the x-direction component, K y represents the unit vector of the y-direction component, K z represents the unit vector of the z-direction component. Each point on the sphere represents a propagation state of light, and the propagation direction of light is the vector direction from the center of the sphere to the point on the sphere. Similarly, if is used to represent the propagation state of light in a homogeneous medium with refractive index n, then all possible propagation states of light form a sphere in k-space with nk0 (the magnitude of nk0 is ) as the radius, as shown in Figure 4b .

[0075] Analysis of the effect of the grating waveguide on the k-vector of light:

[0076] For a general grating waveguide, as shown in Figure 5 , taking the grating waveguide design with the input grating 3 as a one-dimensional grating and the output grating 4 as a two-dimensional grating as an example. Assume that the waveguide substrate 2 is in the x-y plane, and all gratings on the waveguide substrate plane also lie on the x-y plane. The input grating has a grating vector The output grating has grating vectors and According to grating theory, the grating vector (where t = 1, 2, 3) is a vector lying in the x-y plane, its direction is perpendicular to the grating line direction, and its magnitude is where d t is the grating period. For light carrying A vector incident light source, which hits the grating region of the grating waveguide (the input grating 3 and the output grating 4 in the figure) and interacts with the grating vector, resulting in a change in the k-vector of light. Each time light interacts with the grating vector, the k-vector increases. where m = 0, ±1, ±2,..., corresponding to the action order of the grating vector; and because is the in-plane vector in the x-y plane, so the action of the grating vector on the k-vector of light only manifests as the action on the x-y plane component of the k-vector of light. In the figure That is, the vector of the incident light source is usually decomposed into a z-direction component and an in-plane component in the x-y plane The grating only acts on .

[0077] It should be noted that the above analysis of the action of the incident light ray on the K-vector of the grating waveguide is also applicable to the grating waveguide design in which the input grating, the turning grating, and the output grating respectively adopt one-dimensional gratings.

[0078] K-space representation of the grating waveguide:

[0079] Exemplarily, Figure 6 The figure shows a schematic diagram of the K-space of the grating waveguide when the grating waveguide plane is in the x-y plane (only focusing on the in-plane component parallel to the x-y plane in the k-space). Among them, the inner circular surface represents the projection of all possible propagation states of light in the air on the k x -k y plane, and the radius of the inner circle is the illustrated k0 (the magnitude of k0 is ), and the outer circular surface represents the projection of all possible propagation states of light in the waveguide medium with a refractive index of n on the k x -k y plane, and the radius of the outer circle is the illustrated nk0 (the magnitude of nk0 is ). Region I in the figure represents the propagation state of light in the air; Region III represents that light cannot propagate in the air or in the waveguide medium with a refractive index of n, that is, there is no propagation state; Region II represents that light cannot propagate in the air and can only propagate in the waveguide medium with a refractive index of n, that is, light undergoes total reflection propagation in the waveguide medium with a refractive index of n.

[0080] Existing grating waveguide designs generally have the following several methods:

[0081] 1. The grating waveguide includes a waveguide substrate, and the input grating, the turning grating, and the output grating are respectively arranged on the same plane (the upper bottom surface or the lower bottom surface) of the waveguide substrate. The input grating, the turning grating, and the output grating all adopt one-dimensional gratings, and the grating line regions of the input grating, the turning grating, and the output grating do not overlap each other.

[0082] 2. The grating waveguide includes a waveguide substrate. On the upper bottom surface of the waveguide substrate, an input grating and a turning grating are respectively arranged. On the lower bottom surface of the waveguide substrate, an output grating is arranged. The input grating, the turning grating, and the output grating all adopt one-dimensional gratings. The grating line region of the turning grating and the grating line region of the output grating have an overlapping region in space. Here, the grating structures arranged on the upper and lower bottom surfaces of the waveguide substrate can also be interchanged.

[0083] 3. The grating waveguide includes a waveguide substrate. On the same plane (upper bottom surface or lower bottom surface) of the waveguide substrate, an input grating and an output grating are respectively arranged. The input grating adopts a one-dimensional grating, and the output grating adopts a two-dimensional grating.

[0084] For the existing grating waveguide design structure, especially for the case of a grating line overlapping structure with multiple dimensions in the output grating region (including the spatial overlap of grating lines in different planes and the overlap of grating lines in the same plane, etc.), the grating structure receives the projection beam of the imaging device. The grating vector of the grating structure modulates the projection beam to obtain a modulated beam. The modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate. The propagation direction of the modulated beam inside the waveguide substrate satisfies the total reflection condition. The grating vector of the grating structure forms two closed loops in the k space.

[0085] Taking the example that on the same plane (upper bottom surface or lower bottom surface) of the waveguide substrate, a one-dimensional input grating and a two-dimensional output grating are respectively arranged, the k-space design schematic diagram of the existing grating waveguide is as Figure 7 shown. In the figure, the rectangular frame represents the in-plane component frame of the k vector of the FOV projected by the opto-mechanical device on the waveguide plane. The inner circle represents the projection of all possible propagation states of light when propagating in air on the K vector on the waveguide plane. The outer circle represents the projection of all possible propagation states of light when propagating in the waveguide medium with a refractive index of n on the K vector on the waveguide plane. represents the in-plane component of the k vector of the FOV projected by the opto-mechanical device (imaging device) on the waveguide plane (usually it is approximately a rectangular frame). is the grating vector of the input grating. and are the two grating vectors of the output grating (where represents the magnitude of the grating vector, d t is the grating period, where t = Gin, 1, 2).

[0086] As shown in the figure, when all of the following three conditions (1)-(3) are satisfied, the propagation direction of the modulated beam inside the waveguide substrate satisfies the total reflection condition:

[0087]

[0088] With These three grating vectors form two closed loops in k-space.

[0089] The prior art or solution With The purpose of these three k-vectors forming two closed loops in k-space is: during the process of using the grating waveguide as an AR glasses lens, it is ensured that the FOV projected by the optical engine (imaging device) passes through the grating vectors of the coupling grating and the decoupling grating, and finally returns to the original state, that is, when the projected image of the optical engine enters the eye box in the form of a projected light beam through the coupling grating into the waveguide and the decoupling grating out of the waveguide, the waveguide display imaging is distortion-free and aberration-free compared to the projected image of the optical engine.

[0090] Corresponding to the above Figure 7 Schematic k-space design of the grating waveguide, taking a pixel point light source in the projected image of the optical engine (i.e., a point within the rectangle in the above Figure 7 ) as an example, the real-space optical path conduction diagram in the grating waveguide is as shown in Figure 8 The pixel point light source is coupled into the grating and transmitted to the decoupling grating through total reflection and interacts with the decoupling grating, and a Figure 8 The dot matrix path shown in will occur. Among them, the dot matrix path of upward pupil expansion mainly experiences the action of the k-vector shown in loop 1 in Figure 7 . The specific physical process is as follows: 1. Assume that the pixel point light source carries The vector propagates along the lower left direction shown in the figure and hits the coupling grating. After the diffraction effect of the coupling grating, The vector will increase by a And become At this time, the K-vector of light is located in Figure 7 In region II of, and the light is totally reflected and propagated to the right in the waveguide. 2. When the light is totally reflected and propagated to the decoupling grating: for the light on the main path from the coupling grating to the decoupling grating, 1) part of the light will be diffracted by the decoupling grating and increase by another Vector, and at this time the k-vector becomes The light changes from the original rightward total reflection propagation to the right-upward total reflection propagation (so it is also called As the turning k-vector), when it hits the decoupling grating again, part of its light will be diffracted again and increase by a Vector, and at this time the k-vector becomes That is, in addition to the Vector that the light itself has, it has increased a total of (loop 1), and the light will be diffracted out of the waveguide and enter the eye box for imaging in the propagation state projected from the optical engine at the beginning (so it is also called For the coupled-out k vector); part of the light continues to propagate by total internal reflection in the upper right direction until it hits the coupled-out grating again and the diffraction and coupling-out process repeats. 2) The remaining light continues to propagate by total internal reflection to the right and hits the coupled-out grating again. Part of the light repeats the diffraction process in 1) while part of the light continues to propagate by total internal reflection to the right, finally achieving the pupil expansion phenomenon of diffracting while propagating, resulting in a dot matrix pattern as shown in Figure 8 the upper half of the coupled-out grating area.

[0091] Similarly, Figure 8 for the downward pupil expansion dot matrix path in Figure 7 it mainly undergoes the action of the k vector shown in loop 2 in k space. Its physical process is similar to that of loop 1. The difference is that in this process, acts as the turning k vector while acts as the coupled-out k vector, resulting in a dot matrix pattern as shown in Figure 8 the lower half of the coupled-out grating area, which will not be elaborated here. The light coupling-out in both the upper and lower parts of the coupled-out grating area ensures the integrity of the final imaging of the light within the eye box range.

[0092] However, for the solution of using the grating waveguide designed in the existing k space above as the AR glasses lens, when the user actually wears the AR glasses, in addition to being able to observe the image output from the light engine and coupled out into the eye box within the eye box range, the user can usually also observe the rainbow pattern phenomenon formed by the ambient light directly diffracted into the eye box through the coupled-out grating. As an interference background, the rainbow pattern seriously affects the imaging effect of the human eye on the image. The schematic diagram of the formation principle of the rainbow pattern when the existing grating waveguide is used as the AR glasses lens is as shown in Figure 9a shown, Figure 9b is Figure 9a the cross-sectional view on the x-z plane. The ambient light undergoes diffraction under the action of the coupled-out grating, and the diffraction process is accompanied by a dispersion phenomenon. The part of the diffracted light with dispersion that enters the eye box and is observed by the human eye is called the rainbow pattern.

[0093] Therefore, to solve the rainbow pattern problem, the present invention breaks the conventional k space design concept of the grating waveguide. The grating structure receives the projection beam of the imaging device; the grating vector modulates the projection beam to obtain a modulated beam. The modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate. The propagation direction of the modulated beam inside the waveguide substrate all satisfies the total internal reflection condition. The grating vector of the grating structure forms exactly one closed loop in k space, so that the modulated beam after modulating the ambient light by the grating vector is located outside the area that can be observed by the human eye, that is, the effect of avoiding the rainbow pattern is achieved.

[0094] In the present invention, the grating vectors of the grating structure form exactly one closed loop in the K space. On the one hand, it can ensure that the FOV projected by the optical engine, after being affected by the grating vectors of the grating structure on the waveguide substrate, will finally return to the original state. That is, when the projected image of the optical engine enters the eyebox through the grating structure of the waveguide substrate in the form of a projection beam, the waveguide display imaging is distortion - free and aberration - free compared with the projected image of the optical engine. On the other hand, the diffracted light of the ambient light diffracted by the grating structure will not enter the eyebox area, so that the human eye can only observe the image output from the optical engine, coupled out through the waveguide and entering the eyebox within the eyebox range, and will not observe the rainbow pattern phenomenon formed by the ambient light directly diffracted into the eyebox through the grating structure, improving the viewing effect of the human eye on the image output by the waveguide.

[0095] Exemplarily, the grating structure of the present invention can be the following several schemes:

[0096] Scheme 1:

[0097] The grating structure includes an input grating and an output grating.

[0098] The waveguide substrate is provided with an input grating and an output grating on the same plane or different planes.

[0099] The input grating adopts a one - dimensional grating, a two - dimensional grating or a partitioned combined grating of a one - dimensional grating and a two - dimensional grating, and the output grating adopts a two - dimensional grating.

[0100] As Figure 10 shown, it schematically shows the case where the waveguide substrate is provided with an input grating 3 and an output grating 4 on the same plane, the input grating 3 adopts a one - dimensional grating, and the output grating 4 adopts a two - dimensional grating.

[0101] Scheme 2:

[0102] The grating structure includes an input grating and an output grating.

[0103] The waveguide substrate is provided with an input grating and an output grating on the same plane or different planes.

[0104] The input grating adopts a one - dimensional grating, a two - dimensional grating or a partitioned combined grating of a one - dimensional grating and a two - dimensional grating.

[0105] The output grating adopts a partitioned combined grating of a one - dimensional grating and a two - dimensional grating, or a partitioned combined grating of at least two two - dimensional gratings.

[0106] As Figure 11 shown, it schematically shows the case where the waveguide substrate is provided with an input grating 3 and an output grating 4 on the same plane, the input grating 3 can adopt a one - dimensional grating or a two - dimensional grating, and the output grating 4 can adopt a partitioned combined grating of a one - dimensional grating and a two - dimensional grating or a partitioned combined grating of two two - dimensional gratings.

[0107] Solution 3:

[0108] The grating structure includes an input grating, a turning grating, and an output grating.

[0109] The waveguide substrate is provided with an input grating, a turning grating, and an output grating.

[0110] The turning grating and the output grating are located in different planes of the waveguide substrate and are arranged in parallel.

[0111] The input grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0112] The turning grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0113] The output grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0114] There is an overlapping area in space between the grating line area of the turning grating and the grating line area of the output grating.

[0115] As Figure 12 shown, it schematically shows a case where the input grating 3 and the turning grating 5 are respectively arranged on the upper bottom surface of the waveguide substrate 2, the output grating 4 is arranged on the lower bottom surface of the waveguide substrate 2, all the input grating 3, the turning grating 5, and the output grating 4 are one-dimensional gratings, and there is an overlapping area in space between the grating line area of the turning grating 5 and the grating line area of the output grating 4.

[0116] For the above Solution 1 and Solution 2, the grating vectors of the input grating and the output grating form exactly one closed loop in the K space. For example, the input grating has a grating vector The output grating has a grating vector And In the K space, there is exactly one closed loop such that

[0117] For the above Solution 3, the grating vectors of the input grating, the turning grating, and the output grating form exactly one closed loop in the K space. For example, the input grating has a grating vector The turning grating has a grating vector The output grating has a grating vector In the K space, there is exactly one closed loop such that

[0118] Exemplarily, as described above, taking the case where the waveguide substrate is provided with a one-dimensional input grating and a two-dimensional output grating on the same bottom surface (upper bottom surface or lower bottom surface) as an example, the k-space design schematic diagram of the grating waveguide of the present invention is as Figure 13As shown in the figure, the rectangular box in the figure represents the in-plane component box of the k-vector of the FOV projected by the optical engine on the waveguide plane. The inner circular surface represents the projection of all possible propagation states of light on the K-vector on the waveguide plane when light propagates in air. The outer circular surface represents the projection of all possible propagation states of light on the K-vector on the waveguide plane when light propagates in a waveguide medium with a refractive index of n. Represents the in-plane component of the k-vector of the FOV projected by the optical engine (imaging device) on the waveguide plane. Is the grating vector coupled into the grating. And Are the two grating vectors of the grating coupled out (where Represents the magnitude of the grating vector, d t Is the grating period, where t = Gin, 1, 2).

[0119] As shown in the figure, when the following condition (4) is satisfied, the propagation directions of the modulated light beams inside the waveguide substrate all satisfy the total reflection condition:

[0120] And,

[0121] At the same time, as shown in the figure,

[0122] The above formula (4) can also be expressed as And,

[0123] The above formula (5) can also be expressed

[0124] And These three grating vectors form a closed loop in k-space.

[0125] And These three grating vectors form a closed loop in k-space. During the process of using the grating waveguide as an AR glasses lens, on the one hand, it can ensure that the FOV projected by the optical engine will return to its original state after the action of the grating vectors of the grating coupled in and the grating coupled out. That is, when the projected image of the optical engine is coupled into the waveguide through the grating coupled in and coupled out of the waveguide through the grating coupled out and enters the eyebox, the waveguide display imaging is distortion-free and non-distorted compared to the projected image of the optical engine. On the other hand, the diffracted light of the ambient light diffracted by the action of the grating coupled out will not enter the eyebox area, so that the human eye can only observe the image output from the optical engine and coupled out of the waveguide and entering the eyebox within the eyebox range, and will not observe the rainbow pattern phenomenon formed by the direct diffraction of the ambient light into the eyebox through the grating coupled out, greatly improving the viewing effect of the human eye on the image output by the waveguide.

[0126] Corresponding to the aboveFigure 13 k-space design of a schematic grating waveguide (i.e., as shown in Figure 13 shown), and these three grating vectors form a closed loop in k-space), taking a pixel point light source in the projected image of the opto-mechanical device (i.e., a point within the rectangular frame in the above Figure 13 ) as an example, the real-space optical path conduction diagram in the grating waveguide is as shown in Figure 14 shown, and the specific physical process is as follows: 1: Assume that the pixel point light source carries vector and propagates along the lower left direction shown in the figure and hits the input grating. After the diffraction effect of the input grating, the vector will increase by and become At this time, the light undergoes total internal reflection and propagates to the right in the waveguide. 2. When the light undergoes total internal reflection and propagates to the output grating: 1) Part of the light will be diffracted by the output grating and increase by vector again. At this time, the k vector becomes The light changes from the original total internal reflection propagation to the right to the total internal reflection propagation in the upper right direction (so it is also called the turning k vector). When it hits the output grating again, part of the light will be diffracted again and increase by vector. At this time, the k vector becomes That is, in addition to the vector it itself has, this part of the light has increased by (loop 1), then the light will be diffracted out of the waveguide in the propagation state projected from the opto-mechanical device at the beginning and enter the eye box for imaging (so it is also called the output k vector); part of the light will continue to propagate by total internal reflection in the upper right direction until it hits the output grating again and repeats the diffraction and output process. 2) The remaining light will continue to propagate by total internal reflection to the right and hit the output grating again. Part of the light will repeat the diffraction process in 1) while part of the light will continue to propagate by total internal reflection to the right, finally realizing the pupil expansion phenomenon of diffraction while propagating.

[0127] Comparing Figure 8 , Figure 13 the grating vectors of the input grating and the output grating in the grating waveguide only form a closed loop in K space, Figure 14 the real-space optical path conduction route shown in the grating waveguide only contains Figure 8 the loop 1 part shown in Figure 8 , and there is no Figure 13 the loop 2 part shown in That is, the two k vectors of the output grating shown in Figure 8 no longer act as both the turning function and the output function as in but only act as the turning function, Only serves the role of coupling out. And since there is no loop 2 in the real-space optical path conduction route in the grating waveguide in the solution of the present invention, the energy originally conducted through loop 2 will be transferred to loop 1. Compared with the prior art, the energy coupling diffraction efficiency in the coupling-out grating region is improved.

[0128] In order to form exactly one closed loop of the above grating vectors of the grating structure in the K space, exemplarily, the present invention is implemented by adjusting the grating period variation. The grating period of some grating structures on the waveguide substrate can be adjusted, or the grating periods of all grating structures on the waveguide substrate can be adjusted. By adjusting the grating periods of the grating structures, exactly one closed loop of the above grating vectors of the grating structure is formed in the K space.

[0129] Take Figure 13 the grating vector of the coupling-in grating in the shown grating waveguide and the grating vector of the coupling-out grating forming a closed loop in the K space as an example. The period corresponding to the coupling-out grating vector can be mainly adjusted, and then small adjustments are made to the periods corresponding to the coupling-out grating vector and the coupling-in grating vector to ensure that the coupling-in grating vector the coupling-out grating vector and the coupling-out grating vector form exactly one closed loop in the K space.

[0130] The solution of the present invention to form exactly one closed loop of the above grating vectors of the grating structure on the waveguide substrate in the K space, compared with the prior solution of forming two closed loops of the above grating vectors of the grating structure on the waveguide substrate in the K space, will reduce one optical path conduction route in the coupling-out grating region. As the comparative analysis in the above Figure 14 and Figure 8 shows, Figure 14 forming only one closed loop of the grating vector of the coupling-in grating and the grating vector of the coupling-out grating in the K space of the grating waveguide, Figure 14 the real-space optical path conduction route in the shown grating waveguide is only the part of loop 1 shown in Figure 8 and there is no part of loop 2 shown in Figure 8 . Since one optical path conduction route is reduced in the coupling-out grating region, there will be a problem that the projected image of the optical engine passing through the waveguide and coupling out into the human eye will have incomplete imaging. As shown in Figure 14 , taking a pixel point light source in the projected image of the optical engine (i.e., the above Figure 13Taking a point within the middle rectangular frame as an example, its effective imaging coupling-out area (i.e., the light source of this pixel point can successfully enter the eyebox for imaging through the coupling effect of the coupling-out grating area, and this coupling-out grating area is the effective imaging coupling-out area of this pixel point light source) is Figure 14 The rectangular shaded area shown in the figure. When the human eye observes within the entire eyebox range, the problem of missing this pixel may occur. By extrapolating to all pixel points in the projection image of the optical engine, there may be a problem that the projection image of the optical engine passing through the waveguide coupling and entering the human eye has incomplete imaging. Therefore, this is another reason why those skilled in the art adopt the scheme of forming two closed loops rather than one closed loop for the above grating vectors of the grating structure on the waveguide substrate in the K space.

[0131] To prevent the occurrence of the above problems, that is, to prevent the problem that the projection image of the optical engine passing through the waveguide coupling and entering the human eye has incomplete imaging, in the process of adjusting the grating period so that the above grating vectors of the grating structure form exactly one closed loop in the K space, the present invention makes the projection image of the optical engine pass through the waveguide coupling and enter the human eye to be completely imaged by adjusting the grating line direction. The grating line direction of some grating structures on the waveguide substrate can be adjusted, or the grating line direction of all grating structures on the waveguide substrate can be adjusted. At the same time, in order to satisfy the above formula (4) or (5), the grating period of the grating structure may be finely adjusted.

[0132] Taking Figure 13 the grating vector of the input grating in the shown grating waveguide and the grating vector of the output grating forming a closed loop in the K space as an example, the grating line direction of the input grating can be mainly adjusted, and in order to satisfy for closure, the grating line direction of the output grating is finely adjusted. As Figure 15 is the k-space design schematic diagram of the grating waveguide further adjusted based on Figure 13 In the figure, the solid arrows represent the grating vector of the input grating corresponding to the adjusted grating line direction and the grating vector of the output grating The dashed arrows correspond to the grating vector of the input grating before the adjustment of the grating line direction and the grating vector of the output grating Figure 15 Figure a in shows changing the grating line direction of the input grating and thus changing the direction, making rotate clockwise by a small angle to become In this way, the in-plane propagation direction when coming out of the input grating and entering the output grating is adjusted from the original to Figure 15 Figure b in [reference] is an enlarged view of the grating vector adjustment of the coupled-in grating in Figure a. It can be clearly seen that after adjustment, is more downward than before adjustment.

[0133] Corresponding to the above Figure 15 k-space design of the schematic grating waveguide (that is, as Figure 15 shown, these three grating vectors form a closed loop in k-space), taking the central pixel point light source in the projected image of the optical engine (that is, the center point within the rectangular frame in the above Figure 15 ) as an example, the real-space optical path conduction diagram in the grating waveguide is as Figure 16 shown. By comparing Figure 14 it can be seen that Figure 16 the coupled-out dot matrix in [reference] covers the effective imaging coupled-out area of this pixel point light source (that is, the rectangular shaded area in Figure 16 ). Then, the human eye can observe this pixel point light source within the entire eyebox range. Similarly, other pixel point light sources in the projected image of the optical engine can be optimized and adjusted similarly to ensure that the projected image of the optical engine can be fully displayed after being coupled out by the waveguide and entering the human eye.

[0134] Moreover, during the process of fine-tuning the grating line direction of the coupled-out grating, for some pixel point light sources in the projected image of the optical engine (imaging device), their effective imaging coupled-out areas may be as shown in the Figure 16 schematic area ①. When the human eye observes within the entire eyebox range, the problem of missing this pixel may also occur. At this time, the grating line direction of the coupled-out grating can be continuously adjusted to adjust the coupled-out grating vector and so that is closer to area ① (such as Figure 15 in Figure a ). Similarly, for some pixel point light sources, their effective imaging coupled-out areas may be as shown in the Figure 16 schematic area ②. To avoid the problem of missing this pixel imaging, the grating line direction of the coupled-in grating can be continuously adjusted to adjust the coupled-in grating vector so that is more downward and closer to area ②.

[0135] In addition, it should also be noted that for the Figure 7 k-space design of the existing grating waveguide shown (the above grating vectors of the grating structure form two closed loops in k-space), due to the action of other high-order levels of the coupled-out grating, a ghost image will be formed in area I. In the present invention, by forming exactly one closed loop in K-space with the above grating vectors of the grating structure (such as Figure 13 ), no ghost image will be formed in area I.

[0136] In addition, for the grating structure adopted in the present invention as Figure 10 shown, preferably (but not limited to), the grating region of the output grating is located above the pupil's horizontal viewing direction, and the projection beam preferably (but not limited to) enters the grating region of the input grating in an obliquely downward direction. Or, the grating region of the output grating is located below the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in an obliquely upward direction.

[0137] For the grating structure adopted in the present invention as Figure 11 shown in Figure a in [reference], preferably (but not limited to), the grating region of the output grating is located above the pupil's horizontal viewing direction, and the projection beam preferably (but not limited to) enters the grating region of the input grating in an obliquely downward direction.

[0138] For the grating structure adopted in the present invention as Figure 11 shown in Figure b in [reference], preferably (but not limited to), the grating region of the output grating is located below the pupil's horizontal viewing direction, and the projection beam preferably (but not limited to) enters the grating region of the input grating in an obliquely upward direction.

[0139] For the grating structure adopted in the present invention as Figure 12 shown, preferably (but not limited to), the overlapping region of the grating lines of the output grating and the turning grating is located above the pupil's horizontal viewing direction, and the projection beam preferably (but not limited to) enters the grating region of the input grating in an obliquely downward direction. Or, the overlapping region of the grating lines of the output grating and the turning grating is located below the pupil's horizontal viewing direction, and the projection beam enters the grating region of the input grating in an obliquely upward direction.

[0140] The above operation further expands the adjustable range of the grating structure, making it easier to optimize the rainbow pattern phenomenon, that is, the diffracted light of the ambient light diffracted by the grating structure does not enter the eye box area, so that the human eye can only observe the image output from the light engine and coupled out by the waveguide into the eye box within the eye box range, and will not observe the rainbow pattern phenomenon formed by the direct diffraction of the ambient light into the eye box through the grating structure, improving the viewing effect of the human eye on the image output by the waveguide.

[0141] It should be further noted that the oblique incidence of the projection beam in the technical solution of the present invention is only a preferred solution. For Figure 10 , Figure 11 the grating structures shown, the technical solution of the present invention is also applicable to the case where the grating region of the output grating is located in the pupil's horizontal viewing direction and the projection beam enters the grating region of the input grating in a normal incidence direction. For Figure 12For the grating structure shown, the technical solution of the present invention is also applicable to the case where the overlapping region of the grating grid lines of the output grating and the turning grating is located in the pupil's forward viewing direction, and the projection beam enters the grating region of the input grating in the normal incidence direction.

[0142] The present invention also provides a waveguide system, including a grating waveguide device. Among them, the grating waveguide device adopts the above-mentioned grating waveguide device for reducing rainbow patterns. For example, an AR glasses, the lens of the AR glasses adopts the above-mentioned grating waveguide device for reducing rainbow patterns.

[0143] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still modify or equivalently replace the specific implementation manners of the present invention. Any such modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of the claims of the present invention pending approval.

Claims

1. A grating waveguide device for reducing rainbow ripples, characterized in that: The grating waveguide device comprises a waveguide substrate and a grating structure; the grating structure is arranged on the waveguide substrate; The grating structure comprises a first coupling-in grating and a first coupling-out grating, wherein the grating region of the first coupling-out grating has a grating line overlapping structure of multiple dimensions, including: the grating region of the first coupling-out grating comprises a two-dimensional grating; or, the grating structure comprises a second coupling-in grating, a turning grating and a second coupling-out grating, and the grating line region of the turning grating has an overlapping region with the grating line region of the second coupling-out grating; The grating structure receives a projection light beam from an imaging device; The grating structure has a grating vector, and the grating vector modulates the projection light beam to obtain a modulated light beam, and the modulated light beam propagates inside the waveguide matrix or emerges from the inside of the waveguide matrix, and the propagation direction of the modulated light beam modulated by the first coupling grating or the second coupling grating and the turning grating inside the waveguide matrix satisfies the total reflection condition; The method comprises: adjusting the grating period so that the grating vector of the grating structure forms one and only one closed loop in the K space; adjusting the grating period so that the grating vector of the grating structure forms one and only one closed loop in the K space, and adjusting the grating line direction so that the projection light beam of the imaging device is coupled out through the grating waveguide device and enters the human eye to be fully displayed, including: In the case where the grating structure includes the first coupling-in grating and the first coupling-out grating, and the first coupling-out grating includes a two-dimensional grating, the grating vector of the first coupling-in grating and the vector sum of the two grating vectors of the two-dimensional grating are 0, and the vector sum of the horizontal component of the projection light beam light vector, the grating vector of the first coupling-in grating, and the first grating vector of the two-dimensional grating are located outside the first projection area, and the vector sum of the horizontal component of the projection light beam light vector, the grating vector of the first coupling-in grating, and the second grating vector of the two-dimensional grating is located within the first projection area and outside the second projection area; In the case where the grating structure includes the second coupling-in grating, the turning grating and the second coupling-out grating, and the grating line area of ​​the turning grating overlaps with the grating line area of ​​the second coupling-out grating, the sum of the grating vector of the second coupling-in grating, the grating vector of the turning grating and the grating vector of the second coupling-out grating is 0, and the vector sum of the horizontal component of the projection light beam light vector and the grating vector of the second coupling-in grating and the grating vector of the coupling-out grating is located outside the first projection area, and the vector sum of the horizontal component of the projection light beam light vector and the grating vector of the second coupling-in grating and the grating vector of the turning grating is located within the first projection area and outside the second projection area; Among them, the horizontal component of the projection beam light vector is the component of the projection beam on the grating waveguide plane, the first projection area is the projection of the K-space vector sphere determined according to the refractive index of the waveguide substrate on the grating waveguide plane, and the second projection area is the projection of the K-space vector sphere determined according to the refractive index of air on the grating waveguide plane.

2. The grating waveguide device for reducing rainbow ripples according to claim 1, characterized in that: For the case where the grating structure includes a first coupling-in grating and a first coupling-out grating: The waveguide substrate is provided with the first coupling-in grating and the first coupling-out grating in the same plane or in different planes; The first coupling grating is a one-dimensional grating, a two-dimensional grating, or a partitioned combination grating of a one-dimensional grating and a two-dimensional grating; The first outcoupling grating includes not only the two-dimensional grating but also a one-dimensional grating, forming a partitioned combined grating of the one-dimensional grating and the two-dimensional grating.

3. The grating waveguide device for reducing rainbow ripples according to claim 2, characterized in that: The two-dimensional grating is a single two-dimensional grating or a partitioned combination grating of at least two two-dimensional gratings.

4. The grating waveguide device for reducing rainbow ripples according to claim 1, characterized in that: For the case where the grating structure includes a second coupling-in grating, a turning grating and a second coupling-out grating: The turning grating and the second outcoupling grating are located in different planes and are arranged in parallel; The coupling-in grating is a one-dimensional grating, a two-dimensional grating, or a partitioned combination of a one-dimensional grating and a two-dimensional grating; The turning grating adopts a one-dimensional grating, a two-dimensional grating or a partitioned combination grating of a one-dimensional grating and a two-dimensional grating; The outcoupling grating is a one-dimensional grating, a two-dimensional grating or a partitioned combination grating of a one-dimensional grating and a two-dimensional grating.

5. The grating waveguide device for reducing rainbow ripples according to claim 2 or 3, characterized in that: The grating vectors of the first coupling-in grating and the first coupling-out grating form one and only one closed loop in K space.

6. The grating waveguide device for reducing rainbow ripples according to claim 4, characterized in that: The grating vectors of the second coupling-in grating, the turning grating and the second coupling-out grating form one and only one closed loop in K space.

7. The grating waveguide device for reducing rainbow ripples according to claim 2 or 3, characterized in that: The first coupling grating has a grating vector The first outcoupling grating has a grating vector and In K space, there is only one closed loop such that 8. The grating waveguide device for reducing rainbow ripples according to claim 4 or 6, characterized in that: The second coupling grating has a grating vector The turning grating has a grating vector The second outcoupling grating has a grating vector In K space, there is only one closed loop such that 9. The grating waveguide device for reducing rainbow ripples according to claim 2 or 3, characterized in that: The grating area of ​​the first out-coupling grating is located above the pupil in the horizontal viewing direction, and the projection light beam enters the grating area of ​​the in-coupling grating in an oblique downward direction.

10. The grating waveguide device for reducing rainbow ripples according to claim 4, characterized in that: The overlapping area of ​​the grating lines of the second out-coupling grating and the turning grating is located above the pupil in the horizontal viewing direction, and the projection light beam hits the grating area of ​​the in-coupling grating in an oblique downward direction.

11. The grating waveguide device for reducing rainbow ripples according to claim 2 or 3, characterized in that: The grating area of ​​the first out-coupling grating is located below the pupil in the horizontal viewing direction, and the projection light beam enters the grating area of ​​the first in-coupling grating in an oblique upward direction.

12. The grating waveguide device for reducing rainbow ripples according to claim 4, characterized in that: The overlapping area of ​​the grating lines of the second out-coupling grating and the turning grating is located below the pupil's horizontal viewing direction, and the projection light beam hits the grating area of ​​the in-coupling grating in an oblique upward direction.

13. The grating waveguide device for reducing rainbow ripples according to claim 2 or 3, characterized in that: The grating area of ​​the first outcoupling grating is located in the pupil horizontal viewing direction; The projection light beam enters the grating region of the first incoupling grating in a normal incident direction.

14. The grating waveguide device for reducing rainbow ripples according to claim 4, characterized in that: The overlapping area of ​​the grating lines of the second outcoupling grating and the turning grating is located in the pupil horizontal viewing direction; The projection light beam enters the grating region of the coupling grating in a normal incident direction.

15. The grating waveguide device for reducing rainbow ripples according to claim 1, characterized in that: The grating vector of the first outcoupling grating, or the grating vectors of the turning grating and the second outcoupling grating, is set to a size that places the modulated light beam after modulating the ambient light outside an area observable by human eyes.

16. A waveguide system, characterized in that: A grating waveguide device comprising: Wherein, the grating waveguide device adopts the grating waveguide device for reducing rainbow ripples as described in any one of claims 1-15.

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