Waveguide device

Abstract

The utility model provides a waveguide device. The waveguide device comprises a waveguide substrate and a grating structure. The grating structure is arranged on the waveguide substrate; the grating structure receives a projection light beam of the imaging device, and the imaging device adopts an optical machine; 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; and adjusting the grating period to enable the grating vector of the grating structure to form and only have one closed loop in the K space. 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 light beam projection mode, compared with the projection image of the imaging device, the imaging displayed by the waveguide device is undistorted, and on the other hand, diffraction light of ambient light diffracted through the grating structure does not enter the eye box area; therefore, the human eyes cannot observe the rainbow pattern phenomenon in the eye box.

Description

Technical Field

[0001] The utility model belongs to the technical field of augmented reality, and in particular relates to a waveguide device. Background Art

[0002] Augmented Reality (AR) technology refers to the use of certain technical means to provide users with additional information in the real world (the so-called "enhancement"). This technology organically combines the images of the virtual world and the scenes of the real world, and deeply integrates the calculated information with the real world, thereby providing users with richer information and immersive experience.

[0003] Augmented reality technology can be implemented through many hardware platforms, among which the most immersive is wearable augmented reality devices, namely AR glasses. The hardware form of this method is a simple pair of glasses, which guide light into the human eye through the microstructure on the surface of the lens. This hardware implementation method is the most convenient and is the mainstream technology of AR. The purpose of AR glasses lenses 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 in-coupling grating and an out-coupling grating. The in-coupling grating and the out-coupling grating are set on the waveguide substrate. Its basic principle is as follows Figure 1 As shown, the light output by the optical machine 1 (imaging device) is coupled into the grating 3 and coupled into the waveguide matrix 2, and propagates in the waveguide matrix 2 by total reflection. Whenever encountering the out-coupling grating 4, a part of the light is coupled out, and the out-coupled light (the solid line in the direction of the human eye in the figure) enters the human eye, so that the same image as the output of the optical machine 1 can be seen. At the same time, the human eye can see the real world scene (the dotted line in the direction of the human eye in the figure), and the overlap of the two parts can realize the function of augmented reality.

[0004] However, for AR glasses that use grating waveguides as lens solutions, when users actually wear AR glasses, in addition to being able to observe the image that is coupled out from the optical machine output through the grating waveguide and enters the eye box, the human eye can usually also observe the rainbow pattern formed by the ambient light directly diffracted into the eye box through the coupled grating. The rainbow pattern, as an interfering background, seriously affects the human eye's viewing effect of the image. Utility Model Content

[0005] In order to overcome the defects of the prior art, the utility model provides a waveguide device.

[0006] The utility model is realized by the following technical solutions:

[0007] The utility model provides a waveguide device, which comprises a waveguide substrate and a grating structure; the grating structure is arranged on the waveguide substrate;

[0008] The grating structure receives a projection light beam from an imaging device, and the imaging device adopts an optical machine;

[0009] The grating structure has a grating vector, the grating vector modulates the projection light beam to obtain a modulated light beam, the modulated light beam propagates inside the waveguide matrix or emerges from the waveguide matrix, and the propagation direction of the modulated light beam inside the waveguide matrix satisfies the total reflection condition;

[0010] The grating period is adjusted so that the grating vector of the grating structure forms one and only one closed loop in the K space.

[0011] Further, the grating structure includes an in-coupling grating and an out-coupling grating;

[0012] The waveguide substrate is provided with the coupling-in grating and the coupling-out grating in the same plane or in different planes;

[0013] 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;

[0014] The outcoupling grating is a two-dimensional grating or a partitioned combination grating of a one-dimensional grating and a two-dimensional grating.

[0015] Furthermore, the two-dimensional grating is a single two-dimensional grating or a partitioned combination grating of at least two two-dimensional gratings.

[0016] Furthermore, the grating structure includes an in-coupling grating, a turning grating and an out-coupling grating;

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

[0018] 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;

[0019] 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;

[0020] 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;

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

[0022] Furthermore, the grating vectors of the coupling-in grating and the coupling-out grating form one and only one closed loop in K space.

[0023] Furthermore, the grating vectors of the coupling-in grating, the turning grating and the coupling-out grating form one and only one closed loop in the K space.

[0024] Furthermore, the coupling grating has a grating vector The outcoupling grating has a grating vector and

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

[0026] Furthermore, the coupling grating has a grating vector The turning grating has a grating vector The outcoupling grating has a grating vector

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

[0028] Furthermore, by adjusting the grating period so that the grating vector of the grating structure forms one and only one closed loop in the K space, by adjusting the grating line direction, the projection light beam of the imaging device is coupled out through the waveguide device and enters the human eye for complete display.

[0029] Furthermore, the grating area of ​​the 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.

[0030] Furthermore, the overlapping area of ​​the grating lines of the 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.

[0031] Furthermore, the grating area of ​​the out-coupling grating is located below the pupil in the horizontal viewing direction, and the projection light beam enters the grating area of ​​the in-coupling grating in an oblique upward direction.

[0032] Furthermore, the overlapping area of ​​the grating lines of the 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.

[0033] Furthermore, the grating area of ​​the outcoupling grating is located in the pupil horizontal viewing direction;

[0034] The projection light beam enters the grating region of the coupling grating in a normal incident direction.

[0035] Furthermore, the overlapping area of ​​the grating lines of the out-coupling grating and the turning grating is located in the pupil horizontal viewing direction;

[0036] The projection light beam enters the grating region of the coupling grating in a normal incident direction.

[0037] Furthermore, the modulated light beam after the grating vector modulates the ambient light is outside the area observable by human eyes.

[0038] Compared with the prior art, the technical solution of the utility model has the following beneficial effects:

[0039] The utility model provides a waveguide device, which comprises a waveguide matrix and a grating structure. The grating structure is arranged on the waveguide matrix, the grating structure receives a projection beam of an 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 matrix or emerges from the inside of the waveguide matrix, the propagation direction of the modulated beam inside the waveguide matrix satisfies the total reflection condition, and the grating period is adjusted so that the grating vector of the grating structure forms one and only one closed loop in the K space, on the one hand, it can ensure that the FOV projected by the imaging device passes through the waveguide matrix. The grating vector effect of the grating structure of the waveguide substrate will eventually return to its 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 projected light beam, the imaging displayed by the waveguide device is distortion-free and distortion-free compared to 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 area, so that the human eye can only observe the image output from the imaging device and coupled out through the waveguide device into the eye box within the eye box range, and will not observe the rainbow pattern phenomenon formed by the ambient light directly diffracted by the grating structure into the eye box, thereby improving the human eye's viewing effect of the image output by the waveguide device. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0041] Figure 1 This is a schematic diagram of the basic principle of the grating waveguide solution;

[0042] Figure 2 A schematic diagram of a grating vector for an example one-dimensional grating;

[0043] Figure 3 A schematic diagram of a grating vector of an example two-dimensional grating;

[0044] Figure 4a Schematic diagram of K space for light propagating in air;

[0045] Figure 4b Schematic diagram of K space for light propagating in a homogeneous medium with a refractive index of n;

[0046] Figure 5 Schematic diagram of the analysis of the k-vector effect of the grating waveguide on light;

[0047] Figure 6 Schematic diagram of the K-space in-plane component of an exemplary grating waveguide;

[0048] Figure 7 A schematic diagram of k-space design of an existing grating waveguide is shown as an example;

[0049] 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;

[0050] 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;

[0051] Figure 9b for Figure 9a Section diagram on the xz plane;

[0052] Fig.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;

[0053] Fig.11 A second example 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;

[0054] Fig.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;

[0055] Fig.13 The k-space design schematic diagram of the grating waveguide of the utility model is an example;

[0056] Fig.14 For Fig.13 The schematic diagram of k-space design of the grating waveguide of the utility model is a schematic diagram of the real space light path transmission in the grating waveguide given as an example;

[0057] Fig.15 For example, based on Fig.13 Schematic diagram of the k-space design of the adjusted grating waveguide;

[0058] Fig.16 For example, based on Fig.15The schematic diagram of the k-space design of the adjusted grating waveguide is an illustrative schematic diagram of the real-space light path transmission in the grating waveguide.

[0059] Among them, 1-optical machine, 2-waveguide substrate, 3-coupling grating, 4-coupling grating, 5-turn grating. DETAILED DESCRIPTION

[0060] The following will be combined with the embodiments of the utility model to clearly and completely describe the technical solution of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0061] In this article, the terms "first", "second" and other similar words are not intended to imply any order, quantity and importance, but are only used to distinguish different elements. In this article, the terms "one", "an" and other similar words are not intended to indicate that there is only one of the things described, but rather indicate that the relevant description is only for one of the things described, and the things described may have one or more. In this article, the terms "comprise", "include" and other similar words are intended to indicate logical mutual relationships, and cannot be regarded as indicating spatial structural relationships. For example, "A includes B" is intended to indicate that B belongs to A logically, but does not indicate that B is located inside A spatially. 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 indicate that B belongs to A, but B does not necessarily constitute the whole of A, and A may also include other elements such as C, D, and E.

[0062] In this document, the terms "embodiment", "present embodiment", "preferred embodiment" and "one embodiment" do not mean that the relevant description is only applicable to a specific embodiment, but rather that the description may also be applicable to one or more other embodiments. Those skilled in the art should understand that in this document, any description of a certain embodiment can be replaced, combined, or combined in other ways with the relevant description in one or more other embodiments, and the new embodiment generated by the replacement, combination, or combination in other ways is easily conceivable by those skilled in the art and belongs to the protection scope of the present utility model.

[0063] In the description herein, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0064] Raster Vector:

[0065] Rasters have raster vectors, such as

[0066] For a one-dimensional grating, Figure 2 As shown, for example, there is a grating vector, the size of the grating vector is related to the grating period (K = 2π / d, where K represents the size 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.

[0067] For a two-dimensional grating, such as Figure 3 As shown, exemplarily, there are two grating vectors (a first grating vector and a second grating vector), the size of the first grating vector is K1=2π / d1 / sin(a), and the size 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 dimension grating (grating period is d2), and the direction of the second grating vector is perpendicular to the grating line direction of the first dimension grating (grating period is d1), wherein d1 is the grating period of the first dimension grating, d2 is the grating period of the second dimension grating, and a is the angle between the grating line direction of the first dimension grating and the grating line direction of the second dimension grating.

[0068] To be consistent with the one-dimensional grating case, the size of the grating vector of the two-dimensional grating is usually defined as K = 2π / d eff , where K represents the size of the grating vector, d eff The magnitude of the grating period component representing the grating vector direction, for example, K1=2π / d1 / sin(a)=2π / d1 eff , K2=2π / d2 / sin(a)=2π / d2 eff .

[0069] Unless otherwise specified, the grating period in the grating vector size formula of the two-dimensional grating mentioned below is the size of the grating period component in the grating vector direction.

[0070] K-space representation of light propagating in a homogeneous medium:

[0071] The propagation behavior of light in a homogeneous medium can usually be abstracted into k-space for representation and analysis, where 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 a 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 we use To represent the propagation state of light in the air, all possible propagation states of light constitute a k-space with k0 (the size of k0 is ) is a sphere with radius, such as Figure 4a As shown in the figure, K x K represents the unit vector of the x-direction component.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 direction of the vector pointing from the center of the sphere to the point on the sphere. Represents the propagation state of light in a uniform medium with a refractive index of n. All possible propagation states of light constitute a k-space with nk0 (nk0 is ) is a sphere with radius, such as Figure 4b shown.

[0072] Analysis of k-vector effect of grating waveguide on light:

[0073] For general grating waveguides, such as Figure 5 As shown in FIG. 1 , a grating waveguide design in which the coupling-in grating 3 is a one-dimensional grating and the coupling-out grating 4 is a two-dimensional grating is taken as an example. Assume that the waveguide substrate 2 is in the xy plane, and all gratings on the waveguide substrate plane also fall on the xy plane. The coupling-in grating has a grating vector The outcoupling grating has a grating vector and From the grating theory, we know that the grating vector (Here t=1,2,3) is a vector falling in the xy plane, its direction is perpendicular to the grating line direction, and its magnitude is Among them, d t is the grating period. The incident light source of the vector hits the grating area of ​​the grating waveguide (the coupling grating 3 and the coupling grating 4 in the figure) and the grating vector, which is manifested as a change in the k vector of the light. Each time the light interacts with the grating vector, the k vector increases. Among them, m = 0, ±1, ±2, ..., corresponding to the order of action of the grating vector; and because is an in-plane vector of the xy plane, so the effect of the grating vector on the k vector of the light only manifests itself as an effect on the xy plane component of the k vector of the light. That is, the incident light source is usually The vector can be decomposed into the z-component and the xy-plane in-plane component Grating only effect.

[0074] It should be noted that the above analysis of the K-vector effect of incident light passing through a grating waveguide is also applicable to a grating waveguide design in which the coupling-in grating, the turning grating and the coupling-out grating are respectively one-dimensional gratings.

[0075] K-space representation of grating waveguide:

[0076] For example, Figure 6The figure shows the schematic diagram of the grating waveguide K space when the grating waveguide plane is located in the xy plane (only focusing on the in-plane component parallel to the xy plane in the k space), where the inner circular surface represents all possible propagation states of light propagating in the air in the k space. x -k y The projection on the surface, the radius of the inner circle is k0 as shown in the figure (the size of k0 is ), the outer circular surface represents all possible propagation states of light when it propagates in a waveguide medium with a refractive index of n. x -k y The projection on the surface, the radius of the outer circle is nk0 (the size of nk0 is ). Area I in the figure represents the propagation state of light in the air; Area III indicates that light can neither propagate in the air nor in the waveguide medium with a refractive index of n, that is, there is no propagation state; Area II indicates that light cannot propagate in the air but can only propagate in the waveguide medium with a refractive index of n, that is, light propagates in the waveguide medium with a refractive index of n by total reflection.

[0077] The existing grating waveguide designs generally have the following methods:

[0078] 1. The grating waveguide includes a waveguide substrate, and a coupling-in grating, a turning grating and a coupling-out grating are respectively arranged on the same plane (upper bottom surface or lower bottom surface) of the waveguide substrate. The coupling-in grating, the turning grating and the coupling-out grating all use one-dimensional gratings, and the grating line areas of the coupling-in grating, the turning grating and the coupling-out grating do not overlap with each other.

[0079] 2. The grating waveguide includes a waveguide substrate, wherein an in-coupling grating and a turning grating are respectively arranged on the upper bottom surface of the waveguide substrate, and an out-coupling grating is arranged on the lower bottom surface of the waveguide substrate. The in-coupling grating, the turning grating and the out-coupling grating all use one-dimensional gratings, and the grating line area of ​​the turning grating and the grating line area of ​​the out-coupling grating have an overlapping area in space. Here, the grating structures arranged on the upper and lower bottom surfaces of the waveguide substrate can also be interchangeable.

[0080] 3. The grating waveguide includes a waveguide substrate, and a coupling-in grating and a coupling-out grating are respectively arranged on the same plane (upper bottom surface or lower bottom surface) of the waveguide substrate. The coupling-in grating adopts a one-dimensional grating, and the coupling-out grating adopts a two-dimensional grating.

[0081] For the existing grating waveguide design structure, especially for the case where the out-coupled grating region has a grating line overlapping structure with multiple dimensions (including spatial overlap of grating lines in different planes and overlap of grating lines in the same plane, etc.), the grating structure receives the projection light beam of the imaging device, and the grating vector of the grating structure modulates the projection light beam to obtain a modulated light beam. The modulated light beam propagates inside the waveguide matrix or emerges from the waveguide matrix. The propagation direction of the modulated light beam inside the waveguide matrix satisfies the total reflection condition, and the grating vector of the grating structure forms two closed loops in the k-space.

[0082] Taking the case where a one-dimensional coupling-in grating and a two-dimensional coupling-out grating are respectively arranged on the same plane (upper bottom surface or lower bottom surface) of a waveguide substrate, the k-space design schematic diagram of the existing grating waveguide is as follows: Figure 7 As shown in the figure, the rectangular box represents the in-plane component box of the k vector of the FOV projected by the optical machine on the waveguide plane, the inner circular surface represents the projection of the K vector on the waveguide plane in all possible propagation states of light when it propagates in the air, and the outer circular surface represents the projection of the K vector on the waveguide plane in all possible propagation states of light when it propagates in the waveguide medium with a refractive index of n. represents the in-plane component of the k-vector of the FOV projected by the optomechanic (imaging device) in the waveguide plane (usually it is approximated by a rectangular box), is the grating vector coupled into the grating, and are the two grating vectors of the outcoupling grating (where Represents the raster vector size, d t is the grating period, where t=Gin, 1, 2).

[0083] As shown in the figure, when the following three conditions (1)-(3) are all met, the propagation direction of the modulated light beam inside the waveguide matrix satisfies the total reflection condition:

[0084]

[0085]

[0086]

[0087] and These three grating vectors form two closed loops in k-space.

[0088] Existing technology or solutions will and The purpose of these three k-vectors forming two closed loops in k-space is to ensure that the FOV projected by the optical machine (imaging device) will eventually return to its original state after being acted upon by the grating vectors of the coupling-in grating and the coupling-out grating when the grating waveguide is used as an AR glasses lens. That is, when the projected image of the optical machine enters the eye box in the form of a projected light beam through the coupling-in grating coupling-in waveguide and the coupling-out grating coupling-out waveguide, the waveguide display imaging is distortion-free and non-distorted compared to the projected image of the optical machine.

[0089] Corresponding to the above Figure 7 The k-space design of the grating waveguide is shown in FIG. 1 , with a pixel point light source in the projected image of the optical machine (i.e., the above Figure 7Take the point in the rectangular box as an example, the real space light path transmission diagram in the grating waveguide is as follows Figure 8 As shown in the figure, the pixel point light source is coupled into the grating and transmitted to the out-coupled grating through total reflection and interacts with the out-coupled grating, which will occur Figure 8 The dot matrix path shown in FIG. The dot matrix path of the upward pupil expansion mainly undergoes the following process in k-space: Figure 7 The k-vector action shown in loop 1 is as follows: 1. Assume that the pixel point light source carries The vector propagates along the lower left direction of the figure and hits the coupling grating. After diffraction by the coupling grating, The vector will increase by one becomes At this time, the K vector of the light is located at Figure 7 In the II region, the light is totally reflected to the right in the waveguide. 2. When the light is totally reflected and propagates to the out-coupling grating: the light on the main path from the in-coupling grating to the out-coupling grating, 1) part of the light will be diffracted by the out-coupling grating and increase by another vector, then the k vector becomes The light is changed from being totally reflected to the right to being totally reflected to the upper right (so it is also called is the turning k vector), when it hits the outcoupling grating again, part of its light will be diffracted again and add a vector, then the k vector becomes That is, this part of the light has Vector extracellular matrix increases (loop 1), the light will be diffracted and coupled out of the waveguide in the propagation state originally projected from the optical machine to enter the eye box for imaging (hence it is also called 1) is the outgoing k vector); part of the light continues to propagate along the upper right direction with total reflection until it hits the outgoing grating again and repeats the diffraction outgoing process. 2) The remaining light will continue to propagate to the right with total reflection and hit the outgoing grating again. Part of the light will repeat the diffraction process of 1) and part of the light will continue to propagate to the right with total reflection, eventually achieving the pupil expansion phenomenon of propagation and diffraction, as shown in the figure. Figure 8 The dot pattern shown in the upper half of the outcoupling grating area.

[0090] akin, Figure 8 The dot path of the downward pupil expansion in the k-space mainly undergoes the following Figure 7 The k-vector action shown in loop 2 is similar to the physical process in loop 1, except that in this process, Acts as a turning k vector and It acts as a coupled out k vector, and appears as Figure 8 The dot pattern shown in the lower half of the coupling grating area is not described in detail. The upper and lower parts of the coupling grating area have light coupling to ensure the integrity of the final imaging of the light within the eye box.

[0091] However, when the grating waveguide with the existing K-space design is used as the lens of AR glasses, in addition to being able to observe the image output from the optical machine through the waveguide and coupled into the eye box, the human eye can also usually observe the rainbow pattern formed by the ambient light directly diffracted into the eye box through the coupled grating. The rainbow pattern, as an interference background, seriously affects the image viewing effect of the human eye. The schematic diagram of the formation principle of the rainbow pattern phenomenon when the existing grating waveguide is used as the lens of AR glasses is shown in the figure below. Figure 9a As shown, Figure 9b for Figure 9a In the cross-sectional diagram on the xz plane, the ambient light is diffracted by the out-coupling grating, and the diffraction process is accompanied by dispersion. The part of the dispersed diffracted light that enters the eye box and is observed by the human eye is called rainbow pattern.

[0092] Therefore, in order to solve the problem of rainbow patterns, the utility model breaks the conventional k-space design thinking of grating waveguides. The grating structure receives the projection light beam of the imaging device; 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 is emitted from the inside of the waveguide matrix. The propagation direction of the modulated light beam inside the waveguide matrix satisfies 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 light beam after the grating vector modulates the ambient light is located outside the area that can be observed by the human eye, thereby achieving the effect of avoiding rainbow patterns.

[0093] The utility model forms one and only one closed loop in the K space with the grating vector of the grating structure. On the one hand, it can ensure that the FOV projected by the optical machine will eventually return to its original state after the grating vector of the grating structure on the waveguide substrate acts on it, that is, when the projected image of the optical machine enters the eye box through the grating structure of the waveguide substrate in the form of a projected light beam, the waveguide display imaging is distortion-free and distortion-free compared to the projected image of the optical machine. 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 machine 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 ambient light directly diffracted by the grating structure into the eye box, thereby improving the viewing effect of the human eye on the waveguide output image.

[0094] Exemplarily, the grating structure of the present invention can be the following:

[0095] Scenario 1:

[0096] The grating structure includes an incoupling grating and an outcoupling grating.

[0097] The waveguide substrate is provided with an in-coupling grating and an out-coupling grating in the same plane or in different planes.

[0098] The coupling-in 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, and the coupling-out grating is a two-dimensional grating.

[0099] like Fig.10 As shown, it illustrates a situation where a coupling-in grating 3 and a coupling-out grating 4 are arranged on the same plane of a waveguide substrate, the coupling-in grating 3 is a one-dimensional grating, and the coupling-out grating 4 is a two-dimensional grating.

[0100] Scenario 2:

[0101] The grating structure includes an incoupling grating and an outcoupling grating.

[0102] The waveguide substrate is provided with an in-coupling grating and an out-coupling grating in the same plane or in different planes.

[0103] The 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.

[0104] The outcoupling grating adopts a partitioned combination grating of a one-dimensional grating and a two-dimensional grating, or adopts a partitioned combination grating of at least two two-dimensional gratings.

[0105] like Fig.11 As shown, it is illustrated that a coupling-in grating 3 and a coupling-out grating 4 are arranged on the same plane of a waveguide substrate, the coupling-in grating 3 can be a one-dimensional grating or a two-dimensional grating, and the coupling-out grating 4 can be a partitioned combination grating of a one-dimensional grating and a two-dimensional grating or a partitioned combination grating of two two-dimensional gratings.

[0106] Scenario 3:

[0107] The grating structure includes an in-coupling grating, a turning grating and an out-coupling grating.

[0108] The waveguide substrate is provided with an in-coupling grating, a turning grating and an out-coupling grating.

[0109] The turning grating and the outcoupling grating are located in different planes of the waveguide substrate and are arranged in parallel.

[0110] The coupling grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combination of a one-dimensional grating and a two-dimensional grating.

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

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

[0113] There is a spatial overlap between the grating line region of the turning grating and the grating line region of the outcoupling grating.

[0114] like Fig.12As shown, it is illustrated that a coupling-in grating 3 and a turning grating 5 are respectively arranged on the upper bottom surface of the waveguide substrate 2, and a coupling-out grating 4 is arranged on the lower bottom surface of the waveguide substrate 2. The coupling-in grating 3, the turning grating 5 and the coupling-out grating 4 are all one-dimensional gratings, and the grating line area of ​​the turning grating 5 and the grating line area of ​​the coupling-out grating 4 have an overlapping area in space.

[0115] For the above-mentioned schemes 1 and 2, the grating vectors of the coupling-in grating and the coupling-out grating form one and only one closed loop in the K space. For example, the coupling-in grating has a grating vector The outcoupling grating has a grating vector and In K space, there is only one closed loop such that

[0116] For the above solution 3, the grating vectors of the coupling-in grating, the turning grating and the coupling-out grating form one and only one closed loop in the K space. For example, the coupling-in grating has a grating vector Transformation raster to raster vector The outcoupling grating has a grating vector In K space, there is only one closed loop such that

[0117] For example, as described above, taking the case where a one-dimensional coupling-in grating and a two-dimensional coupling-out grating are respectively arranged on the same bottom surface (upper bottom surface or lower bottom surface) of a waveguide substrate as an example, the k-space design schematic diagram of the grating waveguide of the present invention is as follows: Fig.13 As shown in the figure, the rectangular box represents the in-plane component box of the k vector of the FOV projected by the optical machine on the waveguide plane, the inner circular surface represents the projection of the K vector on the waveguide plane in all possible propagation states of light when it propagates in the air, and the outer circular surface represents the projection of the K vector on the waveguide plane in all possible propagation states of light when it propagates in the waveguide medium with a refractive index of n. The in-plane component of the k-vector in the waveguide plane representing the FOV projected by the optomechanical (imaging device), is the grating vector coupled into the grating, and are the two grating vectors of the outcoupling grating (where Represents the raster vector size, d t is the grating period, where t=Gin, 1, 2).

[0118] As shown in the figure, when one of the following conditions (4)-(5) is met, the propagation direction of the modulated light beam inside the waveguide matrix satisfies the total reflection condition:

[0119]

[0120]

[0121] The above formula (4) can also be expressed as and,

[0122] The above formula (5) can also be expressed as and,

[0123] and These three grating vectors form a closed loop in k-space.

[0124] and These three grating vectors form a closed loop in k-space. When the grating waveguide is used as an AR glasses lens, on the one hand, it can ensure that the FOV projected by the optical machine will eventually return to its original state after the action of the grating vectors of the coupling-in grating and the coupling-out grating. That is, when the projected image of the optical machine enters the eye box through the coupling-in grating coupling-in waveguide and the coupling-out grating coupling-out waveguide, the waveguide display imaging is distortion-free and distortion-free compared to the projected image of the optical machine. On the other hand, the diffracted light of the ambient light diffracted by the coupling-out grating will not enter the eye box area, so that the human eye can only observe the image output from the optical machine and coupled out through the waveguide into the eye box within the eye box range, but will not observe the rainbow pattern phenomenon formed by the ambient light directly diffracted through the coupling-out grating and entering the eye box, which greatly improves the human eye's viewing effect of the waveguide output image.

[0125] Corresponding to the above Fig.13 The k-space design of the grating waveguide is shown in FIG. Fig.13 As shown, and These three grating vectors form a closed loop in k-space), with a pixel point light source in the projected image of the optical machine (i.e., the above Fig.13 Take the point in the rectangular box as an example, the real space light path transmission diagram in the grating waveguide is as follows Fig.14 As shown, the specific physical process is: 1: Assume that the pixel point light source carries The vector propagates along the lower left direction of the figure and hits the coupling grating. After diffraction by the coupling grating, The vector will increase by one becomes At this time, the light is totally reflected and propagates to the right in the waveguide. 2. When the light is totally reflected and propagates to the outcoupling grating: 1) Part of the light will be diffracted by the outcoupling grating and increase by another vector, then the k vector becomes The light is changed from being totally reflected to the right to being totally reflected to the upper right (so it is also called is the turning k vector), when it hits the outcoupling grating again, part of its light will be diffracted again and add a vector, then the k vector becomes That is, this part of the light has Vector extracellular matrix increases (loop 1), the light will be diffracted and coupled out of the waveguide in the propagation state originally projected from the optical machine to enter the eye box for imaging (hence it is also called 1) is the outgoing k vector); part of the light continues to propagate in the upper right direction by total reflection until it hits the outgoing grating again and repeats the diffraction outgoing process. 2) The remaining light continues to propagate to the right by total reflection and hits the outgoing grating again, part of the light repeats the diffraction process of 1) and part of the light continues to propagate to the right by total reflection, finally achieving the pupil expansion phenomenon of propagation and diffraction.

[0126] contrast Figure 8 , Fig.13 The grating vector of the coupled-in grating and the grating vector of the coupled-out grating in the grating waveguide form only a closed loop in the K space. Fig.14 The real-space light path in the grating waveguide shown only contains Figure 8 The circuit 1 part shown in Figure 8 The circuit 2 part shown in Fig.13 The two k-vectors of the outcoupling grating shown in No longer like Figure 8 As in the above, each plays a role of transition and coupling, but It only serves as a turning point. And because there is no loop 2 in the real space light path transmission route in the grating waveguide in the solution of the utility model, the energy originally transmitted through loop 2 will be transferred to loop 1, which improves the energy coupling diffraction efficiency of the coupling grating area compared with the prior art.

[0127] In order to form the above grating vector of the grating structure with one and only one closed loop in the K space, the utility model is implemented 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 vector of the grating structure forms one and only one closed loop in the K space.

[0128] by Fig.13 The grating vector of the coupled grating in the grating waveguide is shown and the grating vector of the outcoupling grating Taking the schematic diagram of a closed loop formed in K space as an example, the outcoupling grating vector can be adjusted mainly The corresponding period, and then the coupled grating vector and coupled grating vector The corresponding period is adjusted slightly to ensure the coupling into the grating vector Outcoupled Grating Vector and outcoupled grating vector There is only one closed loop formed in K space.

[0129] The utility model forms the grating vector of the grating structure on the waveguide substrate with one and only one closed loop in the K space. Compared with the existing solution that the grating vector of the grating structure on the waveguide substrate forms two closed loops in the K space, one optical path conduction route is reduced in the out-coupling grating area. Fig.14 and Figure 8 A comparative analysis of Fig.14 The grating vector of the coupled-in grating and the grating vector of the coupled-out grating in the grating waveguide form only a closed loop in the K space. Fig.14 The real-space light path in the grating waveguide shown is only Figure 8 The circuit 1 part shown in Figure 8 As shown in the loop 2 section. Since the out-coupling grating area reduces one light path transmission route, the projected image of the optical machine will be incomplete when it is coupled out through the waveguide and enters the human eye. Fig.14 As shown, a pixel point light source in the projected image of the optical machine (i.e., the above Fig.13 Take the point in the rectangular box as an example, its effective imaging outcoupling area (that is, the pixel point light source can successfully enter the eye box for imaging through the outcoupling effect of the outcoupling grating area, and this outcoupling grating area is the effective imaging outcoupling area of ​​the pixel point light source) is Fig.14 The rectangular shaded area shown in the figure, when the human eye observes within the entire eye box, the pixel may be missing. By analogy, all the pixels in the projected image of the optical machine may be incomplete when the projected image of the optical machine is coupled out through the waveguide and enters the human eye. Therefore, this is another reason why those skilled in the art adopt the solution of forming two closed loops in the K space instead of one closed loop for the grating vectors of the grating structure on the waveguide substrate.

[0130] In order to prevent the above-mentioned problem from occurring, that is, to prevent the problem of incomplete imaging of the projected image of the optical machine after it is coupled out through the waveguide and enters the human eye, the utility model adjusts the grating line direction so that the projected image of the optical machine can be fully imaged after it is coupled out through the waveguide and enters the human eye during the process of adjusting the grating period so that the grating vector of the grating structure forms one and only one closed loop in the K space. 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-mentioned formula (4) or (5), the grating period of the grating structure may be fine-tuned.

[0131] by Fig.13 The grating vector of the coupled grating in the grating waveguide is shown and the grating vector of the outcoupling grating Taking the schematic diagram of a closed loop formed in K space as an example, the grating line direction of the coupled grating can be adjusted mainly to meet To meet the closure requirement, fine-tune the grating line direction of the out-coupling grating. Fig.15 Based on Fig.13 Schematic diagram of the k-space design of the grating waveguide after further adjustment. The solid arrows in the figure represent the grating vector of the coupled grating after the grating line direction is adjusted. and the grating vector of the outcoupling grating The dashed arrow corresponds to the grating vector coupled into the grating before the grating line direction is adjusted. and the grating vector of the outcoupling grating Fig.15 Figure a shows how to change the direction of the coupled grating lines to change direction, so Rotate a small angle clockwise to In this way, the in-plane propagation direction from the coupling-in grating to the coupling-out grating changes from the original Adjust to Fig.15 Figure b is an enlarged view of the grating vector adjustment of the coupled grating in Figure a. It can be clearly seen that after adjustment Compared with before adjustment The direction is further down.

[0132] Corresponding to the above Fig.15 The k-space design of the grating waveguide is shown in FIG. Fig.15 As shown,

[0133] These three grating vectors form a closed loop in k-space), with the central pixel point light source in the projected image of the optical machine (i.e. Fig.15Taking the center point in the rectangular box as an example, the real space light path transmission diagram in the grating waveguide is as follows Fig.16 As shown, compared Fig.14 visible, Fig.16 The outcoupling dot matrix in the pixel covers the effective imaging outcoupling area of ​​the pixel point light source (i.e. Fig.16 The human eye can observe the pixel point light source within the entire eye box. Similarly, other pixel point light sources in the projected image of the optical machine can be similarly optimized and adjusted to ensure that the projected image of the optical machine can be fully displayed after being coupled out through the waveguide and entering the human eye.

[0134] In the process of fine-tuning the grating line direction of the out-coupling grating, for some pixel point light sources in the image projected by the optical machine (imaging device), the effective imaging out-coupling area may be Fig.16 As shown in the schematic ① area, when the human eye observes within the entire eye box, the pixel may be missing. At this time, the grating line direction of the out-coupling grating can be further adjusted to adjust the out-coupling grating vector. and Make The direction can be closer to area ① (such as Fig.15 in a ). Similarly, for some pixel point light sources, the effective imaging outcoupling area may be Fig.16 As shown in the schematic diagram of area ②, in order to avoid the problem of missing pixel imaging, the grating line direction of the coupled grating can be further adjusted to adjust the coupled grating vector Make The direction is further downward, closer to area ②.

[0135] Furthermore, it should be noted that Figure 7 In the k-space design of the prior art grating waveguide shown in FIG. 1 (the grating vectors of the grating structure form two closed loops in the k-space), due to the effect of other high-order outcoupling gratings, the rectangular frame will form a ghost image in the I region. The utility model forms only one closed loop (such as Fig.13 ), no ghost image will be formed in area I.

[0136] In addition, for the utility model, Fig.10 The grating structure shown can preferably (but not limited to) place the grating area of ​​the out-coupling grating above the pupil in the horizontal direction, and the projection light beam can preferably (but not limited to) hit the grating area of ​​the in-coupling grating in an oblique downward direction. Alternatively, the grating area of ​​the out-coupling grating is located below the pupil in the horizontal direction, and the projection light beam hits the grating area of ​​the in-coupling grating in an oblique upward direction.

[0137] For the utility model, Fig.11The grating structure shown in Figure a in the figure can preferably (but not limited to) locate the grating area of ​​the out-coupling grating above the pupil in the horizontal direction, and the projection light beam can preferably (but not limited to) hit the grating area of ​​the in-coupling grating in an oblique downward direction.

[0138] For the utility model, Fig.11 The grating structure shown in Figure b may preferably (but not limited to) locate the grating area of ​​the out-coupling grating below the pupil in the horizontal direction, and the projection light beam may preferably (but not limited to) hit the grating area of ​​the in-coupling grating in an oblique upward direction.

[0139] For the utility model, Fig.12 The grating structure shown can preferably (but not limited to) position the overlapping area of ​​the grating lines of the out-coupling grating and the turning grating above the pupil's horizontal viewing direction, and the projection light beam can preferably (but not limited to) hit the grating area of ​​the in-coupling grating in an oblique downward direction. Alternatively, the overlapping area of ​​the grating lines of the 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.

[0140] The above operation further expands the adjustable range of the grating structure and thus makes it easier to optimize the rainbow pattern phenomenon, that is, to achieve that 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 machine 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 ambient light directly diffracted by the grating structure into the eye box, thereby improving the human eye's viewing effect of the waveguide output image.

[0141] It should be further explained that the oblique incidence of the projected light beam in the technical solution of the present utility model is only a preferred solution. Fig.10 , Fig.11 The technical solution of the utility model is also applicable to the case where the grating area of ​​the out-coupling grating is located in the pupil horizontal direction and the projected light beam is incident on the grating area of ​​the in-coupling grating in the normal incident direction. Fig.12 The grating structure shown in the figure, the technical solution of the utility model is also applicable to the situation where the overlapping area of ​​the grating lines of the out-coupling grating and the turning grating is located in the pupil level direction, and the projected light beam enters the grating area of ​​the in-coupling grating in the normal incident direction.

[0142] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field can still modify or replace the specific implementation methods of the present invention. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A waveguide device, characterized in that: The waveguide device comprises a waveguide substrate and a grating structure; the grating structure is arranged on the waveguide substrate; The grating structure receives a projection light beam from an imaging device, and the imaging device adopts an optical machine; The grating structure has a grating vector, the grating vector modulates the projection light beam to obtain a modulated light beam, the modulated light beam propagates inside the waveguide matrix or emerges from the waveguide matrix, and the propagation direction of the modulated light beam inside the waveguide matrix satisfies the total reflection condition; The grating period is adjusted so that the grating vector of the grating structure forms one and only one closed loop in the K space.

2. The waveguide device according to claim 1, characterized in that The grating structure includes an in-coupling grating and an out-coupling grating; The waveguide substrate is provided with the coupling-in grating and the coupling-out grating in the same plane or in different planes; 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 outcoupling grating is a two-dimensional grating or a partitioned combination grating of a one-dimensional grating and a two-dimensional grating.

3. The waveguide device 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 waveguide device according to claim 1, characterized in that The grating structure includes an in-coupling grating, a turning grating and an out-coupling grating; The turning grating and the 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; The grating line region of the turning grating and the grating line region of the outcoupling grating have an overlapping region in space.

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

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

7. The waveguide device according to claim 2 or 3, characterized in that: The coupling-in grating has a grating vector The outcoupling grating has a grating vector and In K space, there is only one closed loop such that 8. The waveguide device according to claim 4 or 6, characterized in that: The coupling-in grating has a grating vector The turning grating has a grating vector The outcoupling grating has a grating vector In K space, there is only one closed loop such that 9. The waveguide device according to claim 1, characterized in that By adjusting the grating period, the grating vector of the grating structure forms one and only one closed loop in the K space, and by adjusting the grating line direction, the projection light beam of the imaging device is coupled out through the waveguide device and enters the human eye for complete display.

10. The waveguide device according to claim 2 or 3, characterized in that: The grating area of ​​the 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.

11. The waveguide device according to claim 4, characterized in that The overlapping area of ​​the grating lines of the 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.

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

13. The waveguide device according to claim 4, characterized in that The overlapping area of ​​the grating lines of the out-coupling grating and the turning grating is located below the pupil in the horizontal viewing direction, and the projection light beam hits the grating area of ​​the in-coupling grating in an oblique upward direction.

14. The waveguide device according to claim 2 or 3, characterized in that: The grating area of ​​the outcoupling 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 waveguide device according to claim 4, characterized in that The overlapping area of ​​the grating lines of the out-coupling 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.

16. The waveguide device according to claim 1, characterized in that The modulated light beam after the grating vector modulates the ambient light is outside the area observable by human eyes.

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