Grating waveguide device and display system

Abstract

The invention provides a grating waveguide device and a display system, and the device comprises a waveguide substrate and a grating structure. The grating structure is arranged on the waveguide substrate; the grating structure receives a projection beam of the imaging device; the grating structure is provided with a grating vector, the grating vector modulates a projection light beam to obtain a modulated light beam, the modulated light beam is propagated in the waveguide substrate or emitted from the interior of the waveguide substrate, and the propagation direction of the modulated light beam in the waveguide substrate meets the total reflection condition; the grating vectors of the grating structure form and have only one closed loop. On one hand, when a projection image of the imaging device enters the eye box through the grating structure of the waveguide substrate in a beam projection mode, compared with the projection image of the imaging device, the imaging displayed by the grating waveguide device is undistorted, and on the other hand, diffraction light diffracted by ambient light through the grating structure does not enter the area of the eye box; therefore, the human eyes cannot observe the rainbow pattern phenomenon in the eye box.

Description

[0001] This application is a divisional application. The filing date of the original application is May 27, 2024, the application number of the original application is 202410658035.8, and the title of the invention of the original application is: A grating waveguide device and a waveguide system for reducing rainbow patterns. Technical Field

[0002] The present invention belongs to the technical field of augmented reality, and particularly relates to a grating waveguide device and a display system. Background Art

[0003] 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 integrates the images of the virtual world and the scenes of the real world, and through in-depth integration of the calculated information with the real world, it provides users with richer information and immersive experiences.

[0004] 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, propagates in the waveguide substrate 2 by total internal reflection, and every time it encounters the output grating 4, a part of the light is coupled out. 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.

[0005] However, for the AR glasses lens solution using a grating waveguide, 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 pattern phenomenon formed by the ambient light directly diffracting into the eye box through the output grating. The rainbow pattern, as an interfering background, seriously affects the viewing effect of the human eye on the image. Summary of the Invention

[0006] In order to overcome the defects of the prior art, the present invention provides a grating waveguide device and a display system.

[0007] The present invention is implemented through the following technical solutions:

[0008] The present invention provides a grating waveguide device, which includes a waveguide substrate, an input grating and an output grating arranged on the waveguide substrate; the output grating includes a two-dimensional grating line region;

[0009] The input grating is used to couple image light into the waveguide substrate; the vector sum of the first sub-vector of the image light and the grating vector of the input grating is located within a first projection region and outside a second projection region;

[0010] The sum vector of the vector sum and the first grating vector of the two-dimensional grating line region is located within the first projection region and outside the second projection region; the sum vector of the vector sum and the second grating vector of the two-dimensional grating line region is located outside the first projection region;

[0011] The sum of the grating vector of the input grating, the first grating vector and the second grating vector is 0;

[0012] Wherein: the first sub-vector is the sub-vector of the image light in the plane where the grating vector is located; the first projection region is the projection region of the K-space vector sphere determined according to the refractive index of the waveguide substrate in the plane where the grating vector is located; the second projection region is the projection region of the K-space vector sphere determined according to the refractive index of air in the plane where the grating vector is located.

[0013] Further, the output grating further includes a one-dimensional grating line region.

[0014] Further, the grating vector of the one-dimensional grating line region is the second grating vector;

[0015] The one-dimensional grating line region is arranged on the first side of the two-dimensional grating line region, and the first side is the side pointed to by the sum vector of the vector sum and the first grating vector.

[0016] Further, it further includes a turning grating;

[0017] The grating vector of the turning grating is the first grating vector;

[0018] The turning grating is arranged on the second side of the two-dimensional grating line region, and the second side is the opposite side of the side pointed to by the sum vector of the vector sum and the first grating vector.

[0019] Further, the two-dimensional grating line region includes a first two-dimensional grating and a second two-dimensional grating;

[0020] The pointing side of the first grating vector of the first two-dimensional grating is opposite to that of the first grating vector of the second two-dimensional grating, and the pointing side of the second grating vector of the first two-dimensional grating is opposite to that of the second grating vector of the second two-dimensional grating;

[0021] The first two-dimensional grating is disposed on the first side of the second two-dimensional grating, and the first side is the pointing side of the sum vector of the vector sum and the first grating vector of the first two-dimensional grating.

[0022] Further, the coupling grating includes a one-dimensional coupling region, and / or the coupling grating includes a two-dimensional coupling region.

[0023] Further, in the case where the coupling grating includes both the one-dimensional coupling region and the two-dimensional coupling region:

[0024] One grating vector of the two-dimensional coupling region is the same as the grating vector of the one-dimensional coupling region; or,

[0025] The vector sum of the two grating vectors of the two-dimensional coupling region is the same as the grating vector of the one-dimensional coupling region.

[0026] Further, at least by reducing the grating period corresponding to the first grating vector and / or the second grating vector, the sum vector of the vector sum and the first grating vector is located within the first projection region and outside the second projection region, and the sum vector of the vector sum and the second grating vector is located outside the first projection region.

[0027] Further, the grating line direction of the coupling grating, the grating line directions corresponding to the first grating vector and the second grating vector are set such that the image light rays in each incident direction are coupled into the waveguide substrate through the coupling grating and are coupled out by the coupling-out grating, so that the image light rays in each incident direction are received by the visual receptor after being coupled out;

[0028] Wherein, the image light rays in each incident direction are the light rays that are irradiated onto the coupling grating and are used to cooperate to form a complete imaging image.

[0029] The present invention also provides a grating waveguide device, including a waveguide substrate, a coupling grating, a one-dimensional turning grating, and a one-dimensional coupling-out grating disposed on the waveguide substrate;

[0030] The coupling grating is used to couple image light rays into the waveguide substrate; the first sub-vector of the image light rays and the vector sum of the grating vectors of the coupling grating are located within the first projection region and outside the second projection region;

[0031] The one-dimensional turning grating includes a first grating line region; the one-dimensional output grating includes a second grating line region; the projections of the first grating line region and the second grating line region on the plane where the grating vector lies coincide;

[0032] The sum vector of the vector sum and the first grating vector of the first grating line region is located within the first projection region and outside the second projection region; the sum vector of the vector sum and the second grating vector of the second grating line region is located outside the first projection region;

[0033] The vector sum of the grating vector of the input grating, the first grating vector, and the second grating vector is 0;

[0034] Wherein: the first component vector is the component vector of the image light ray on the plane where the grating vector lies; the first projection region is the projection region of the K-space vector sphere determined according to the refractive index of the waveguide substrate on the plane where the grating vector lies; the second projection region is the projection region of the K-space vector sphere determined according to the refractive index of air on the plane where the grating vector lies.

[0035] Furthermore, the one-dimensional output grating further includes a third grating line region;

[0036] The grating vector of the third grating line region is the second grating vector;

[0037] The third grating line region is disposed on the first side of the second grating line region, and the first side is the side pointed to by the sum vector of the vector sum and the first grating vector.

[0038] Furthermore, the one-dimensional turning grating further includes a fourth grating line region;

[0039] The grating vector of the fourth grating line region is the first grating vector;

[0040] The fourth grating line region is disposed on the second side of the first grating line region, and the second side is the side opposite to the direction pointed to by the sum vector of the first grating line region grating vector.

[0041] Furthermore, the input grating includes a one-dimensional input region, and / or the input grating includes a two-dimensional input region.

[0042] Furthermore, in the case where the input grating includes both the one-dimensional input region and the two-dimensional input region:

[0043] One grating vector of the two-dimensional input region is the same as the grating vector of the one-dimensional input region; or,

[0044] The vector sum of the two grating vectors of the two-dimensional input region is the same as the grating vector of the one-dimensional input region.

[0045] Further, at least by reducing the grating period of the one-dimensional turning grating and / or the one-dimensional output grating, the sum vector of the vector sum and the first grating vector is located within the first projection area and outside the second projection area, and the sum vector of the vector sum and the second grating vector is located outside the first projection area.

[0046] Further, the grating line direction of the input grating, the grating line directions of the one-dimensional turning grating and the one-dimensional output grating are set such that the image light rays in each incident direction are coupled into the waveguide body through the input grating and are coupled out by the output grating, so that the image light rays in each incident direction are received by the visual receptor after being coupled out;

[0047] Wherein, the image light rays in each incident direction are the light rays that irradiate the input grating and are used to cooperate to form a complete imaging image.

[0048] The present invention also provides a display system, including an optical engine and the above-mentioned grating waveguide device;

[0049] The output end of the optical engine faces the input grating of the grating waveguide device, and is used to irradiate the image light rays to the input grating.

[0050] Further, the output grating is located above the reference datum plane; the optical axis of the optical engine points obliquely downward to the input grating;

[0051] The output grating is located below the reference datum plane; the optical axis of the optical engine points obliquely upward to the input grating; or,

[0052] The output grating covers the area where the reference datum plane is located; the optical axis of the optical engine is directly opposite to the input grating;

[0053] Wherein: the reference datum plane is the plane where the optical axis of the visual receptor is located when the visual receptor faces the grating waveguide device and looks straight ahead.

[0054] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0055] The present invention provides a grating waveguide device, which 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 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. The propagation direction of the modulated beam inside the waveguide substrate all satisfies the total reflection condition. The grating vectors of the grating structure form one and only one closed loop. Forming one and only one closed loop for the grating vectors of the grating structure, on the one hand, can ensure that the FOV projected by the imaging device, after being affected by the grating vectors of the grating structure of the waveguide substrate, will eventually return to the original state, that is, when the projected image of the imaging device enters the eyebox through the projection beam and the grating structure of the waveguide substrate, the imaging displayed by the grating waveguide device is distortion - free and aberration - free 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 eyebox area, so that the human eye can only observe the image output from the imaging device and coupled out through the grating waveguide device 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 structure, improving the viewing effect of the human eye on the image output by the grating waveguide device. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] 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 - described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0057] Figure 1 Schematic diagram of the basic principle of the grating waveguide solution;

[0058] Figure 2 Schematic diagram of the grating vector of an example one - dimensional grating;

[0059] Figure 3 Schematic diagram of the grating vector of an example two - dimensional grating;

[0060] Figure 4a Schematic diagram of the K - space of light propagating in air;

[0061] Figure 4b Schematic diagram of the K - space of light propagating in a uniform medium with a refractive index of n;

[0062] Figure 5 Schematic diagram of the analysis of the action of the k - vector of light by an example grating waveguide;

[0063] Figure 6 Schematic diagram of the in - plane components of the K - space of an example grating waveguide;

[0064] Figure 7 Schematic diagram of the k-space design of an existing grating waveguide for illustration;

[0065] Figure 8 For Figure 7 Schematic diagram of the real-space optical path conduction in the grating waveguide exemplarily given for the k-space design of the existing grating waveguide;

[0066] Figure 9a Schematic diagram of the formation principle of rainbow patterns when the existing grating waveguide is used as an AR glasses lens;

[0067] Figure 9b For Figure 9a Cross-sectional view on the x-z plane;

[0068] Figure 10 First exemplary schematic diagram of the grating structure under the concept that all grating vectors of the grating structure form one and only one closed loop in the K space based on the present invention;

[0069] Figure 11 Second exemplary schematic diagram of the grating structure under the concept that all grating vectors of the grating structure form one and only one closed loop in the K space based on the present invention;

[0070] Figure 12 Third exemplary schematic diagram of the grating structure under the concept that all grating vectors of the grating structure form one and only one closed loop in the K space based on the present invention;

[0071] Figure 13 Schematic diagram of the k-space design of the grating waveguide of the present invention for illustration;

[0072] Figure 14 For Figure 13 Schematic diagram of the real-space optical path conduction in the grating waveguide exemplarily given for the k-space design of the grating waveguide of the present invention for illustration;

[0073] Figure 15 Exemplarily given based on Figure 13 Adjusted k-space design schematic diagram of the grating waveguide;

[0074] Figure 16 Exemplarily given based on Figure 15 Schematic diagram of the real-space optical path conduction in the grating waveguide exemplarily given for the adjusted k-space design schematic diagram of the grating waveguide.

[0075] Among them, 1-optical machine, 2-waveguide substrate, 3-coupling grating, 4-output grating, 5-turning grating. Detailed implementation manner

[0076] The embodiments of the present invention will be described clearly and completely with reference to 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0077] In this document, terms such as "first", "second" and other similar terms do not imply any order, quantity or importance, but are only used to distinguish different elements. In this document, terms such as "a", "an" and other similar terms do not mean that there is only one such thing, but mean that the relevant description only refers to one of such things, and such things may have one or more. In this document, terms such as "comprising", "including" and other similar terms are intended to represent a logical relationship and should not be regarded as representing a spatial structure relationship. 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 terms such as "comprising", "including" and other similar terms 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.

[0078] In this document, terms such as "embodiment", "this embodiment", "preferred embodiment", "an embodiment" do not mean that the relevant description only applies to a specific embodiment, but mean 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, and 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.

[0079] In the description of this document, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0080] Grating vector:

[0081] A grating has a grating vector. For example,

[0082] For a one-dimensional grating, 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), and the direction of the grating vector is perpendicular to the grating line direction of the one-dimensional grating.

[0083] For a two-dimensional grating, such as Figure 3 shown, exemplary, 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.

[0084] To be consistent with the one-dimensional grating case, the magnitude K of the grating vector of the two-dimensional grating 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. Exemplary, the above K1 = 2π / d1 / sin(a) = 2π / d1 eff , K2 = 2π / d2 / sin(a) = 2π / d2 eff .

[0085] 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 direction of the grating vector.

[0086] K-space representation of light propagation in a homogeneous medium:

[0087] For light propagating in a homogeneous medium, its propagation behavior can usually be abstracted into the 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 constitute a sphere in k-space with k0 (the magnitude of k0 is ) as the radius, as Figure 4a shown. 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 Indicates the propagation state of light in a homogeneous medium with refractive index n. All possible propagation states of light constitute a sphere in k-space with a radius of nk0 (the magnitude of nk0 is ), as shown in Figure 4b .

[0088] Analysis of the action of the grating waveguide on the k-vector of light:

[0089] For a general grating waveguide, as shown in Figure 5 , take the design of a grating waveguide 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 the grating theory, the grating vector (where t = 1, 2, 3) is a vector lying in the x-y plane, whose direction is perpendicular to the grating line direction and the magnitude is where d t is the grating period. For an incident light source carrying a vector, its interaction with the grating region of the grating waveguide (the input grating 3 and the output grating 4 in the figure) with the grating vector is manifested as a change in the k-vector of light. Each time light interacts with the grating vector, the k-vector increases by where m = 0, ±1, ±2,..., corresponding to the action order of the grating vector; and because is a vector in the x-y plane, so the action of the grating vector on the k-vector of light is only manifested as the action on the x-y plane component of the k-vector of light. In the figure that is, the vector of the usually incident light source can be decomposed into a z-direction component and an in-plane component in the x-y plane The grating only acts on .

[0090] 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 design of a grating waveguide in which the input grating, the turning grating, and the output grating respectively adopt one-dimensional gratings.

[0091] K-space representation of the grating waveguide:

[0092] Exemplarily, Figure 6 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 k-space). Among them, the inner circular surface represents all possible propagation states of light when light propagates in air in k x -k yThe projection on the plane, the radius of the inner circle is shown as k0 (the size of k0 is ), and the outer circle represents all possible propagation states of light when light propagates in the waveguide medium with refractive index n in the projection on the k x -k y plane. The radius of the outer circle is shown as nk0 (the size of nk0 is ). Region I in the figure represents the propagation state of light in air; Region III represents that light can neither propagate in air nor in the waveguide medium with refractive index n, that is, there is no propagation state; Region II represents that light cannot propagate in air but can only propagate in the waveguide medium with refractive index n, that is, light undergoes total internal reflection propagation in the waveguide medium with refractive index n.

[0093] The existing grating waveguide designs generally have the following several methods:

[0094] 1. The grating waveguide includes a waveguide substrate. On the same plane (the upper bottom surface or the lower bottom surface), an input grating, a turning grating, and an output grating are respectively arranged on 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 with each other.

[0095] 2. The grating waveguide includes a waveguide substrate. An input grating and a turning grating are respectively arranged on the upper bottom surface of the waveguide substrate, and an output grating is arranged on the lower bottom surface of the waveguide substrate. The input grating, the turning grating, and the output grating all adopt one-dimensional gratings, and there is an overlapping region in space between the grating line region of the turning grating and the grating line region of the output grating. Here, the grating structures arranged on the upper and lower bottom surfaces of the waveguide substrate can also be interchanged.

[0096] 3. The grating waveguide includes a waveguide substrate. An input grating and an 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 adopts a one-dimensional grating, and the output grating adopts a two-dimensional grating.

[0097] 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 projected light beam of the imaging device, and the grating vector of the grating structure modulates the projected light beam to obtain a modulated light beam. The modulated light beam propagates inside the waveguide substrate or exits from inside the waveguide substrate. The propagation direction of the modulated light beam inside the waveguide substrate satisfies the total internal reflection condition, and the grating vector of the grating structure forms two closed loops in the k space.

[0098] Taking the example of the waveguide substrate respectively arranging a one-dimensional input grating and a two-dimensional output grating on the same plane (the upper bottom surface or the lower bottom surface), the k-space design schematic diagram of the existing grating waveguide is as Figure 7As 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 circle 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 circle 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 (usually it approximates a rectangular box). 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).

[0099] As shown in the figure, when all of the following three conditions (1)-(3) are satisfied, the propagation direction of the modulated light beam inside the waveguide substrate satisfies the total reflection condition:

[0100]

[0101] And These three grating vectors form two closed loops in k space.

[0102] The prior art or solution makes And 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 grating coupled in and the grating coupled out, 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 grating coupled in and the grating coupled out, the waveguide display imaging is distortion-free and non-distorted compared to the projected image of the optical engine.

[0103] 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 (that is, a point inside the above Figure 7 rectangular box) as an example, the real-space optical path conduction diagram inside the grating waveguide is as Figure 8 shown. The pixel point light source is coupled into the grating and transmitted to the grating coupled out through total reflection and interacts with the grating coupled out, and there will be Figure 8 the dot matrix path shown in. 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: 1. Assume that the pixel point light source carries The vector propagates in the lower left direction as shown in the figure and hits the input grating. After the diffraction effect of the input grating, the vector will increase by one and become At this time, the K vector of the light is located in Figure 7 Region II of, and the light totally internally reflects and propagates to the right in the waveguide. 2. When the light totally internally reflects and propagates to the output grating: For the light on the main path from the input grating to the output grating, 1) Part of the light will be diffracted by the output grating and increase by one vector. At this time, the k vector becomes The light changes from the original totally internally reflecting propagation to the right to the totally internally reflecting 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 one vector. At this time, the k vector becomes That is, in addition to the vector it originally has, this part of the light has increased by a total of (Loop 1), and then the light will be diffracted out of the waveguide in the original propagation state projected from the optical machine and enter the eye box for imaging (so it is also called the output k vector); part of the light will continue to totally internally reflect and propagate in the upper right direction until it hits the output grating again and repeats the diffraction output process. 2) The remaining light will continue to totally internally reflect and propagate 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 totally internally reflect and propagate to the right, finally realizing the pupil expansion phenomenon of diffracting while propagating, and a dot matrix pattern as shown in the upper half of the output grating area in Figure 8 appears.

[0104] Similarly, Figure 8 for the dot matrix path of downward pupil expansion in, it mainly experiences the action of the k vector as shown in Loop 2 in Figure 7 in the 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 output k vector, and a dot matrix pattern as shown in the lower half of the output grating area in Figure 8 appears. The specific details will not be elaborated here. The fact that there is light output from both the upper and lower parts of the output grating area ensures the integrity of the final imaging of the light within the eye box range.

[0105] However, in the solution of using the grating waveguide with the above-mentioned existing K-space design 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 optical engine and coupled out into the eye box through the waveguide 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 output grating. As an interference background, the rainbow pattern seriously affects the viewing effect of the image by the human eye. 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 sectional view on the x-z plane. The ambient light is diffracted by the action of the output grating, and the dispersion phenomenon occurs during the diffraction process. 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.

[0106] Therefore, to solve the problem of the rainbow pattern, the present invention breaks the conventional K-space design thinking 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, and the modulated beam propagates inside the waveguide substrate or exits from inside the waveguide substrate. The propagation directions of the modulated beam inside the waveguide substrate all satisfy the total reflection condition, and the grating vector of the grating structure forms one and only one closed loop in the K space, so that the modulated beam after the grating vector modulates the ambient light is located outside the area that can be observed by the human eye, that is, the effect of avoiding the rainbow pattern is achieved.

[0107] The present invention forms one and only one closed loop of the grating vector of the grating structure in the K space. On the one hand, it can ensure that the FOV projected by the optical engine will finally return to the original state after the action of the grating vector of the grating structure on the waveguide substrate, that is, when the projected image of the optical engine enters the eye box through the grating structure of the waveguide substrate in the form of a projection beam, the waveguide display imaging is distortion-free and non-distorted 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 eye box area, so that the human eye can only observe the image output from the optical engine and coupled out into the eye box within the eye box range, and will not observe the rainbow pattern phenomenon formed by the ambient light directly diffracted into the eye box through the grating structure, improving the viewing effect of the human eye on the image output by the waveguide.

[0108] Exemplarily, the grating structure of the present invention can be the following several solutions:

[0109] Solution 1:

[0110] The grating structure includes an input grating and an output grating.

[0111] The waveguide substrate is provided with an input grating and an output grating on the same plane or different planes.

[0112] The input grating uses 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 uses a two-dimensional grating.

[0113] As Figure 10 shown, it schematically shows the case where the input grating 3 and the output grating 4 are arranged on the same plane of the waveguide substrate, the input grating 3 uses a one-dimensional grating, and the output grating 4 uses a two-dimensional grating.

[0114] Solution 2:

[0115] The grating structure includes an input grating and an output grating.

[0116] The input grating and the output grating are arranged on the same plane or different planes of the waveguide substrate.

[0117] The input grating uses a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0118] The output grating uses 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.

[0119] As Figure 11 shown, it schematically shows the case where the input grating 3 and the output grating 4 are arranged on the same plane of the waveguide substrate. The input grating 3 can use a one-dimensional grating or a two-dimensional grating, and the output grating 4 can use a partitioned combined grating of a one-dimensional grating and a two-dimensional grating or a partitioned combined grating of two two-dimensional gratings.

[0120] Solution 3:

[0121] The grating structure includes an input grating, a turning grating, and an output grating.

[0122] The waveguide substrate is provided with an input grating, a turning grating, and an output grating.

[0123] The turning grating and the output grating are located on different planes of the waveguide substrate and are arranged in parallel.

[0124] The input grating can use a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0125] The turning grating can use a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0126] The output grating can use a one-dimensional grating, a two-dimensional grating, or a partitioned combined grating of a one-dimensional grating and a two-dimensional grating.

[0127] The grating line region of the turning grating and the grating line region of the output grating have an overlapping region in space.

[0128] As Figure 12As shown, it schematically shows that the waveguide substrate 2 is provided with an input grating 3 and a turning grating 5 on the upper bottom surface respectively, and the waveguide substrate 2 is provided with an output grating 4 on the lower bottom surface. The input grating 3, the turning grating 5 and the output grating 4 all adopt one-dimensional gratings, and the grating line region of the turning grating 5 and the grating line region of the output grating 4 have an overlapping region in space.

[0129] For the above-mentioned Scheme 1 and Scheme 2, the grating vectors of the input grating and the output grating form one and only 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 only one closed loop such that

[0130] For the above-mentioned Scheme 3, the grating vectors of the input grating, the turning grating and the output grating form one and only 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 only one closed loop such that

[0131] Exemplarily, as described above, taking the waveguide substrate as an example, which 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) respectively, the schematic diagram of the k-space design of the grating waveguide of the present invention is as Figure 13 shown. In the figure, the rectangular frame represents the in-plane component frame of the k vector of the FOV projected by the optomechanical device on the waveguide plane. The inner circular surface represents the projection of all possible propagation states of light in the waveguide plane when light propagates in air on the K vector of the waveguide plane, and the outer circular surface represents the projection of all possible propagation states of light in the waveguide plane when light propagates in a waveguide medium with a refractive index of n on the K vector of the waveguide plane. represents the in-plane component of the k vector of the FOV projected by the optomechanical device (imaging device) on the waveguide plane. 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).

[0132] 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:

[0133] And,

[0134] Meanwhile, as shown in the figure,

[0135] The above formula (4) can also be expressed as Moreover,

[0136]

[0137] The above formula (5) can also be expressed as

[0138] Together with These three grating vectors form a closed loop in the k - space.

[0139] Together with These three grating vectors form a closed loop in the k - space. During the process of using the grating waveguide as the lens of an AR glasses, on the one hand, it can ensure that the FOV projected by the optical engine, after being affected by the grating vectors of the input grating and the output grating, will finally return to the original state. That is, when the projected image of the optical engine is coupled into the waveguide through the input grating and coupled out of the waveguide through the output grating and enters the eye box, the image displayed by the waveguide 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 output grating will not enter the eye box area, so that the human eye can only observe the image output from the optical engine and coupled out of 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 output grating, greatly improving the viewing effect of the image output by the waveguide for the human eye.

[0140] Corresponding to the above - mentioned Figure 13 Schematic k - space design of the grating waveguide (that is, as Figure 13 shown, Together with These three grating vectors form a closed loop in the k - space), taking a pixel point light source in the projected image of the optical engine (that is, 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 Figure 14 shown. 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 being diffracted by the input grating, vector will increase by a 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 another vector. 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 For the turning k vector), when it hits the output grating again, part of the light will diffract again and add a vector, and at this time the k vector becomes That is, in addition to the vector it itself has, a total of (Loop 1) is added. Then the light will diffract and couple out into the waveguide in the propagation state initially projected from the optical engine and enter the eye box for imaging (so it is also called the output coupling k vector); part of the light will continue to propagate by total reflection in the upper right direction until it hits the output grating again and repeats the diffraction and coupling out process. 2) The remaining light will continue to propagate by total reflection to the right and hit the output grating again. Part of the light will repeat the diffraction process in 1), and part of the light will continue to propagate by total reflection to the right, finally realizing the pupil expansion phenomenon of diffracting while propagating.

[0141] Comparison 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 the K space. Figure 14 The actual space optical path conduction route in the grating waveguide shown only contains Figure 8 the part of Loop 1 shown in Figure 8 and does not exist Figure 13 the part of Loop 2 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 coupling function as in but only act as the turning function, and only act as the output coupling function. And because there is no Loop 2 in the actual space optical path conduction route in the grating waveguide of 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 output coupling diffraction efficiency in the output grating area is improved.

[0142] In order to form exactly one closed loop in the K space for the above grating vectors of the grating structure, exemplarily, the present invention is achieved by adjusting the grating period change. The grating period of some grating structures on the waveguide substrate can be adjusted, or the grating period of all grating structures on the waveguide substrate can be adjusted. By adjusting the grating period of the grating structure, the above grating vectors of the grating structure are formed into exactly one closed loop in the K space.

[0143] Taking Figure 13 the schematic diagram of forming a closed loop in the K space for the grating vector of the input grating and the grating vector of the output grating in the grating waveguide shown as an example, the output grating vector can be mainly adjusted and the grating vector of the output grating The corresponding period, and then couple out the grating vector and the coupled-in grating vector Make a small adjustment to the corresponding period, so as to ensure that the coupled-in grating vector The coupled-out grating vector and the coupled-out grating vector Form exactly one closed loop in the K space.

[0144] The solution of the present invention to form exactly one closed loop in the K space for the above grating vectors of the grating structure on the waveguide substrate, compared with the existing solution of forming two closed loops in the K space for the above grating vectors of the grating structure on the waveguide substrate, will reduce one optical path conduction route in the coupled-out grating region, as shown in the above Figure 14 and Figure 8 Comparative analysis, Figure 14 Only form one closed loop in the K space for the grating vector of the coupled-in grating and the grating vector of the coupled-out grating in 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 coupled-out grating region, there will be a problem that the projected image of the optical engine passing through the waveguide and coupled 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., a point within the rectangular frame in the above Figure 13 ) as an example, its effective imaging coupled-out area (i.e., the area where the pixel point light source can successfully enter the eye box for imaging through the coupling effect of the coupled-out grating region, and this coupled-out grating region is the effective imaging coupled-out area of the pixel point light source) is the rectangular shaded area shown in Figure 14 . When the human eye observes within the entire eye box range, the problem of missing this pixel may occur. By extrapolating to all pixel points in the projected image of the optical engine, there may be a problem that the projected image of the optical engine passing through the waveguide and coupled out into the human eye will have incomplete imaging. Therefore, this is another reason why those skilled in the art adopt the solution of forming two closed loops rather than one closed loop in the K space for the above grating vectors of the grating structure on the waveguide substrate.

[0145] To prevent the occurrence of the above problems, that is, to prevent the problem of incomplete imaging when the projected image of the optical engine enters the human eye through waveguide coupling, during the process of adjusting the grating period so that the above grating vector of the grating structure forms exactly one closed loop in the K space, the present invention adjusts the grating line direction so that the projected image of the optical engine can be completely imaged after passing through waveguide coupling and entering the human eye. 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.

[0146] 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 satisfy the closure, the grating line direction of the output grating is finely adjusted. As Figure 15 shown in Figure 13 the k-space design schematic diagram of the grating waveguide after further adjustment, the solid arrows in the figure 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 that changing the grating line direction of the input grating changes the direction, making rotate clockwise by a small angle to become In this way, the in-plane propagation direction when exiting the input grating and entering the output grating is changed from the original Figure 15 Figure b in is an enlarged view of the grating vector adjustment of the input grating in Figure a, and it can be clearly seen that the adjusted is more downward than the one before adjustment.

[0147] Corresponding to the k-space design of the grating waveguide shown above Figure 15 (that is, as shown in Figure 15 the three grating vectors form a closed loop in the 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 as an example, the real-space optical path conduction diagram in the grating waveguide is as shown in Figure 15 Figure 16 ​As shown in the comparison Figure 14 It can be seen that Figure 16 the output dot matrix in Figure 16 covers the effective imaging output area of the pixel point light source (i.e., the rectangular shadow area in

[0148] ), then the human eye can observe the 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. Figure 16 During the fine-tuning of the grating line direction of the output grating, for some pixel point light sources in the projected image of the optical engine (imaging device), their effective imaging output areas may be as shown in area ① indicated in and When the human eye observes within the entire eyebox range, the problem of missing pixels may also occur. At this time, the grating line direction of the output grating can be continuously adjusted to adjust the output grating vector so that the direction of Figure 15 in is closer to area ① (such as Figure 16 ). Similarly, for some pixel point light sources, their effective imaging output areas may be as shown in area ② indicated in To avoid the problem of missing pixel imaging, the grating line direction of the input grating can be continuously adjusted to adjust the input grating vector so that the direction of

[0149] is more downward and closer to area ②. Figure 7 In addition, it should be noted that for the k-space design of the existing grating waveguide shown in Figure 13 (the above grating vectors of the grating structure form two closed loops in k-space), due to the action of other high-order terms of the output grating, ghost images will be formed in area I. In the present invention, by forming one and only one closed loop of the above grating vectors of the grating structure in K-space (such as

[0150] ), no ghost images will be formed in area I. Figure 10 In addition, for the grating structure adopted in the present invention as shown in

[0151] For the grating structure adopted in the present invention as shown in Figure 11For the grating structure shown in Figure a in [ ], 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.

[0152] For the present invention, for the grating structure shown in Figure b in [ ] Figure 11 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.

[0153] For the present invention, for the grating structure shown in [ ] Figure 12 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.

[0154] The above operations further expand 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 region, so that the human eye can only observe the image output from the light engine and coupled out through 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 image output by the waveguide for the human eye.

[0155] 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 the grating structures shown in [ ] Figure 10 、 Figure 11 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 the grating structure shown in [ ] Figure 12 the technical solution of the present invention is also applicable to the case where the overlapping region of the grating lines of the output grating and the turning 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.

[0156] The present invention also provides a display system, including a grating waveguide device. Among them, the grating waveguide device adopts the above-mentioned grating waveguide device. For example, an AR glasses, and the lens of the AR glasses adopts the above-mentioned grating waveguide device.

[0157] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. 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, characterized in that, It includes a waveguide substrate, an input grating and an output grating disposed on the waveguide substrate; the output grating includes a two-dimensional grating line region; The input grating is used to couple image light into the waveguide substrate; the vector sum of the first sub-vector of the image light and the grating vector of the input grating is located within the first projection region and outside the second projection region; The sum vector of the vector sum and the first grating vector of the two-dimensional grating line region is located within the first projection region and outside the second projection region; the sum vector of the vector sum and the second grating vector of the two-dimensional grating line region is located outside the first projection region; The sum of the grating vector of the input grating, the first grating vector and the second grating vector is 0; Wherein: the first sub-vector is the sub-vector of the image light in the plane where the grating vector is located; the first projection region is the projection region of the K-space vector sphere determined according to the refractive index of the waveguide substrate in the plane where the grating vector is located; the second projection region is the projection region of the K-space vector sphere determined according to the refractive index of air in the plane where the grating vector is located.

2. The grating waveguide device according to claim 1, wherein The output grating further includes a one-dimensional grating line region.

3. The grating waveguide device according to claim 2, characterized in that, The grating vector of the one-dimensional grating line region is the second grating vector; The one-dimensional grating line region is disposed on the first side of the two-dimensional grating line region, and the first side is the pointing side of the sum vector of the vector sum and the first grating vector.

4. The grating waveguide device according to claim 1, characterized in that, It further includes a turning grating; The grating vector of the turning grating is the first grating vector; The turning grating is disposed on the second side of the two-dimensional grating line region, and the second side is the opposite side of the pointing side of the sum vector of the vector sum and the first grating vector.

5. The grating waveguide device according to claim 1, characterized in that, The two-dimensional grating line region includes a first two-dimensional grating and a second two-dimensional grating; The pointing sides of the first grating vector of the first two-dimensional grating and the first grating vector of the second two-dimensional grating are opposite, and the pointing sides of the second grating vector of the first two-dimensional grating and the second grating vector of the second two-dimensional grating are opposite; The first two-dimensional grating is disposed on the first side of the second two-dimensional grating, and the first side is the pointing side of the sum vector of the vector sum and the first grating vector of the first two-dimensional grating.

6. The grating waveguide device according to any one of claims 1-5, characterized in that, The input grating includes a one-dimensional input region, and / or the input grating includes a two-dimensional input region.

7. The grating waveguide device according to claim 6, wherein In the case where the input grating includes both the one-dimensional input region and the two-dimensional input region: One grating vector of the two-dimensional input region is the same as the grating vector of the one-dimensional input region; or, The vector sum of the two grating vectors of the two-dimensional input region is the same as the grating vector of the one-dimensional input region.

8. The grating waveguide device according to any one of claims 1-5, characterized in that At least by reducing the grating period corresponding to the first grating vector and / or the second grating vector, the sum vector and the sum vector of the first grating vector are located within the first projection region and outside the second projection region, and the sum vector and the sum vector of the second grating vector are located outside the first projection region.

9. The grating waveguide device according to any one of claims 1-5, characterized in that The grating line direction of the coupling grating, the grating line directions corresponding to the first grating vector and the second grating vector are set such that the image light rays in each incident direction are coupled into the waveguide body through the coupling grating and are coupled out by the coupling-out grating, so that the image light rays in each incident direction are received by the visual receptor after being coupled out; Wherein, the image light rays in each incident direction are the light rays that irradiate on the coupling grating and are used to cooperate to form a complete imaging image.

10. A grating waveguide device, characterized in that, It includes a waveguide body, a coupling grating, a one-dimensional turning grating and a one-dimensional coupling-out grating arranged on the waveguide body; The coupling grating is used to couple the image light rays into the waveguide body; the vector sum of the first sub-vector of the image light rays and the grating vector of the coupling grating is located within the first projection area and outside the second projection area; The one-dimensional turning grating includes a first grating line area; the one-dimensional coupling-out grating includes a second grating line area; the projections of the first grating line area and the second grating line area on the plane where the grating vector is located coincide; The sum vector of the vector sum and the first grating vector of the first grating line area is located within the first projection area and outside the second projection area; the sum vector of the vector sum and the second grating vector of the second grating line area is located outside the first projection area; The vector sum of the grating vector of the coupling grating, the first grating vector and the second grating vector is 0; Wherein: the first sub-vector is the sub-vector of the image light rays in the plane where the grating vector is located; the first projection area is the projection area of the K-space vector sphere determined according to the refractive index of the waveguide body on the plane where the grating vector is located; the second projection area is the projection area of the K-space vector sphere determined according to the refractive index of air on the plane where the grating vector is located.

11. The grating waveguide device according to claim 10, characterized in that, The one-dimensional coupling-out grating further includes a third grating line area; The grating vector of the third grating line area is the second grating vector; The third grating line area is arranged on the first side of the second grating line area, and the first side is the pointing side of the sum vector of the vector sum and the first grating vector.

12. The grating waveguide device according to claim 10, wherein, The one-dimensional turning grating further includes a fourth grating line area; The grating vector of the fourth grating line area is the first grating vector; The fourth grating line area is arranged on the second side of the first grating line area, and the second side is the opposite side of the pointing direction of the sum vector of the vector sum and the grating vector of the first grating line area.

13. The grating waveguide device according to any one of claims 10-12, characterized in that: The coupling grating includes a one-dimensional coupling area, and / or, the coupling grating includes a two-dimensional coupling area.

14. The grating waveguide device according to claim 13, wherein In the case where the coupling grating includes both the one-dimensional coupling area and the two-dimensional coupling area: One grating vector of the two-dimensional coupling area is the same as the grating vector of the one-dimensional coupling area; or, The vector sum of the two grating vectors of the two-dimensional coupling area is the same as the grating vector of the one-dimensional coupling area.

15. The grating waveguide device according to any one of claims 10-12, wherein At least by reducing the grating period of the one-dimensional turning grating and / or the one-dimensional output grating, the sum vector of the vector sum and the first grating vector is located within the first projection area and outside the second projection area, and the sum vector of the vector sum and the second grating vector is located outside the first projection area.

16. The grating waveguide device according to any one of claims 10-12, characterized in that The grating line directions of the input grating, the one-dimensional turning grating, and the one-dimensional output grating are set such that the image light rays in each incident direction are coupled into the waveguide body through the input grating and coupled out by the output grating, so that the image light rays in each incident direction are received by the visual receptor after being coupled out; Among them, the image light rays in each incident direction are the light rays that irradiate the input grating and are used to cooperate to form a complete imaging image.

17. A display system, characterized in that, Comprising an optical machine and a grating waveguide device according to any one of claims 1-16; The output end of the optical machine faces the input grating of the grating waveguide device for irradiating the image light rays to the input grating.

18. The display system according to claim 17, characterized in that The output grating is located above the reference datum plane; the optical axis of the optical machine points obliquely downward to the input grating; The output grating is located below the reference datum plane; the optical axis of the optical machine points obliquely upward to the input grating; or, The output grating covers the area where the reference datum plane is located; the optical axis of the optical machine is directly opposite to the input grating; Wherein: the reference datum plane is the plane where the optical axis of the visual receptor is located when the visual receptor faces the grating waveguide device directly and looks straight ahead.

Images