Diffractive grating waveguide and augmented reality device thereof

Abstract

The application provides a diffraction grating waveguide and an augmented reality device thereof, wherein a first out-coupling grating vector and a second out-coupling grating vector of the out-coupling grating are set as two vectors with different sizes and directions, and a vector sum of the in-coupling grating vector, the first out-coupling grating vector and the second out-coupling grating vector is 0, so that for an incident vector of any incident light ray in an incident light beam, the following conditions can be completely achieved: a vector component of the incident vector of the incident light ray and a vector sum of the in-coupling grating vector are located outside a first projection area and inside a second projection area; the incident vector of the incident light ray and the vector sum of the in-coupling grating vector and the first out-coupling grating vector are located outside the first projection area and inside the second projection area; and the incident vector of the incident light ray and the vector sum of the in-coupling grating vector and the first out-coupling grating vector are located outside the first projection area and inside the second projection area, so that the diffraction grating waveguide can display uniform images with high light efficiency.

Description

Technical Field

[0001] This invention belongs to the field of augmented reality technology, specifically relating to a diffraction grating waveguide and its augmented reality device. Background Technology

[0002] Augmented Reality (AR) technology refers to providing users with additional information in the real world through certain technical means (i.e., "enhancement"). This technology organically integrates images from the virtual world with scenes from the real world, providing users with richer information and an immersive experience by deeply integrating the calculated information with the real world.

[0003] Augmented reality (AR) technology can be implemented through many hardware platforms, with wearable AR devices offering the most immersive experience. AR glasses, as a type of wearable AR device, guide light into the eyes through the microstructures on the lens surface, providing a convenient way to achieve AR. Currently, mature AR glasses lens technologies mainly include prism solutions, birdbath solutions, freeform surface solutions, off-axis holographic lens solutions, and diffraction grating waveguide solutions. Among these, the diffraction grating waveguide solution is widely recognized as the mainstream AR glasses lens solution due to its advantages such as small size and light weight, large eye movement range, large field of view, and mass production feasibility.

[0004] Diffraction grating waveguides can increase the range of eye movement through two-dimensional pupil expansion, thereby achieving a strong sense of immersion and a good visual experience. There are currently two existing two-dimensional pupil expansion schemes using diffraction grating waveguides: One-dimensional grating waveguide scheme: such as Figure 1 As shown, a coupling grating 2, a bend grating 3, and a coupling grating 4 are respectively disposed on the waveguide substrate 1. The coupling grating, bend grating, and coupling grating are all one-dimensional gratings. The light emitted by the optomechanical system is coupled into the waveguide substrate through the coupling grating and propagates through total internal reflection. It achieves two-dimensional pupil expansion through the combined action of the bend grating and the coupling grating, and achieves image formation by coupling out the light through the coupling grating.

[0005] Two-dimensional grating waveguide schemes: such as Figure 2 As shown, a coupling grating 2 and a coupling grating 4 are respectively set on the waveguide substrate 1. The coupling grating is a two-dimensional grating. The light emitted by the optomechanical system is coupled into the waveguide substrate through the coupling grating and propagates through total internal reflection. It then passes through the coupling grating to achieve two-dimensional pupil expansion and light coupling imaging.

[0006] Compared to Scheme 1, Scheme 2 does not require a turning grating, so the exit pupil region (light coupling region) of the two-dimensional grating is larger and the space utilization is higher, making it an ideal scheme for two-dimensional pupil expansion using diffraction grating waveguides.

[0007] In existing two-dimensional grating waveguide schemes, the two grating vectors of the coupled grating are of equal magnitude. When light emitted from the optomechanical system enters the coupled grating at a large incident angle, propagates through total internal reflection in the waveguide substrate, and is coupled out through the coupled grating to form an image, the waveguide display image is non-uniform and has low optical efficiency. Summary of the Invention

[0008] To overcome the shortcomings of the prior art, the present invention provides a diffraction grating waveguide and its augmented reality device.

[0009] This invention is achieved through the following technical solution: This invention provides a diffraction grating waveguide, comprising a waveguide substrate, wherein an input grating and an output grating are disposed on the waveguide substrate, and the output grating is a two-dimensional grating; The coupling grating is used to couple the incident beam into the waveguide substrate for total internal reflection propagation; the coupling grating is used to perform two-dimensional pupil expansion and coupling imaging on the beam propagating in total internal reflection within the waveguide substrate. The coupling grating has a coupling grating vector. The coupled grating has a first coupled grating vector. Second coupled grating vector The first coupled grating vector Second coupled grating vector The vectors have different magnitudes and different directions; The coupled grating vector First coupled grating vector Second coupled grating vector The vector sum is 0; Each incident ray in the incident beam has an incident vector. The incident vector of the incident ray The vector components and the coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector The first coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector The first coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

[0010] Furthermore, the incident vector of the incident ray The vector component is the incident vector of the incident ray. Vector components in the waveguide substrate plane; The first projection area is the first circular projection area of ​​the first K space vector sphere determined according to the refractive index of air onto the waveguide substrate plane; The second projection region is the second circular projection region on the waveguide substrate plane of the second K-space vector sphere determined according to the refractive index of the waveguide substrate. The first center of the first circular projection area coincides with the second center of the second circular projection area.

[0011] Furthermore, the coupled grating vector With the first coupled grating vector The vectors have different magnitudes and different directions; The coupled grating vector With the second coupled grating vector The vectors have different magnitudes and different directions.

[0012] Furthermore, the coupled grating vector With the first coupled grating vector Or the second coupled grating vector The vectors are of equal magnitude; the coupled grating vectors With the first coupled grating vector Second coupled-out grating vector The vector directions are different.

[0013] Furthermore, the incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector The first coupled grating vector The vector sum is located at a first predetermined position, which is located outside the first circular projection area and within the second circular projection area; The incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector The first coupled grating vector The vector sum is located at a second set position, which is located outside the first circular projection area and within the second circular projection area.

[0014] Furthermore, the first and second predetermined positions are respectively located on predetermined circular trajectories; The third center of the defined circular trajectory coincides with either the first or second center, and the radius of the defined circular trajectory satisfies the following formula: in, This indicates the radius of the circular trajectory. This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area.

[0015] Furthermore, in, This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area. This indicates the wavelength of light in air. It represents the refractive index of the waveguide substrate.

[0016] Furthermore, when the first set position and the second set position are respectively located on the set circular trajectory, the first coupled grating vector is determined according to the following formula. Second coupled grating vector : in, This represents the first output grating vector. This represents the second output grating vector. This represents the incident vector of the central incident ray of a known incident beam. This represents the known coupled-in grating vector. Indicates perpendicular to unit vector, This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area.

[0017] Furthermore, the coupled grating is a one-dimensional grating or a two-dimensional grating.

[0018] The present invention also provides an augmented reality device, including a projection optical engine and a diffraction grating waveguide; The diffraction grating waveguide described above is used. The projection optical engine is used to project an incident beam onto the diffraction grating waveguide.

[0019] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: The diffraction grating waveguide provided by this invention, for a two-dimensional grating waveguide scheme, specifies the first coupled-out grating vector of the coupled-out grating. Second coupled grating vector Adjustments are made to the first coupled-out grating vector of the coupled-out grating. Second coupled grating vector Set as two vectors of unequal magnitude and different directions, coupled to the grating vector. First coupled grating vector Second coupled grating vector The vector sum is 0, thus for any incident vector in the incident beam... It can completely realize: the incident vector of the incident ray. The vector components and the coupled grating vector The incident vector of the incident ray lies outside the first projection region but within the second projection region. With the coupled grating vector First coupled grating vector The incident vector of the incident ray lies outside the first projection region but within the second projection region. With the coupled grating vector First coupled grating vector The vector sum is located outside the first projection area but within the second projection area. This ensures that the diffraction grating waveguide displays a uniform image with high luminous efficiency. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a one-dimensional grating waveguide scheme for a diffraction grating waveguide; Figure 2 A schematic diagram of a two-dimensional grating waveguide scheme for a diffraction grating waveguide; Figure 3 Example: A schematic diagram of the grating vector of a one-dimensional grating; Figure 4 A schematic diagram of the grating vector for a two-dimensional grating, as an example; Figure 5 A schematic diagram illustrating the k-vector effect of a grating waveguide on light, used as an example; Figure 6a A schematic diagram of K-space, representing the propagation of light in air; Figure 6b In order to have a refractive index A schematic diagram of K-space propagation of light in a homogeneous medium; Figure 7 A schematic diagram of the K-space for light propagation in a grating waveguide, as an example; Figure 8aA schematic diagram of the K-space propagation of light in an existing two-dimensional grating waveguide scheme when the incident light beam is incident on the grating waveguide at a small angle; Figure 8b A schematic diagram of the K-space design of existing two-dimensional grating waveguide schemes when the incident beam is incident on the grating waveguide at a large angle; Figure 9 A first schematic diagram of the K-space design of the two-dimensional grating waveguide scheme of the diffraction grating waveguide of the present invention when the incident beam is incident on the grating waveguide at a large angle; Figure 10 The second schematic diagram of the K-space design of the two-dimensional grating waveguide scheme of the present invention is shown when the incident beam is incident on the grating waveguide at a large angle.

[0022] Wherein, 1-waveguide substrate, 2-coupled grating, 3-turn grating, 4-coupled grating. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In this document, the terms "first," "second," and other similar words are not intended to imply any order, quantity, or importance, but are merely used to distinguish different elements. The terms "one," "a," and other similar words are not intended to indicate the existence of only one of the stated things, but rather that the description refers only to one of the stated things, which may have one or more. The terms "comprising," "including," and other similar words are intended to indicate a logical relationship, not a spatial relationship. For example, "A includes B" means that logically B belongs to A, not that spatially B is located inside A. Furthermore, the meanings of the terms "comprising," "including," and other similar words should be considered open-ended, not closed. For example, "A includes B" means that B belongs to A, but B does not necessarily constitute all of A; A may also include other elements such as C, D, and E.

[0025] In this document, the terms "embodiment," "this embodiment," "preferred embodiment," and "one embodiment" do not imply that the description applies only to one specific embodiment, but rather that such description may also be applicable to one or more other embodiments. Those skilled in the art will understand that any description made herein with respect to one embodiment can be substituted, combined, or otherwise incorporated with the descriptions in one or more other embodiments. Such substitutions, combinations, or other incorporations resulting in new embodiments are readily conceived by those skilled in the art and fall within the scope of protection of this invention.

[0026] In this description, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0027] Raster vector: A grating has a grating vector, for example, For a one-dimensional grating, such as Figure 3 As shown, for example, there is a grating vector, the size of which is related to the grating period ( ,in, The magnitude of the grating vector represents the size of the one-dimensional grating. (where is the period of a one-dimensional grating), and the direction of the grating vector is perpendicular to the direction of the grating lines of the one-dimensional grating.

[0028] For two-dimensional gratings, such as Figure 4 As shown, for example, there are two grating vectors (a first grating vector and a second grating vector), the size of the first grating vector is... The size of the second grating vector is The direction of the first grating vector is parallel to that of the second-dimensional grating (grating period is...). The direction of the grating lines is perpendicular to that of the first-dimensional grating (the grating period is...). The grid lines are perpendicular, where The grating period of the first-dimensional grating. Let be the grating period of the second-dimensional grating, and 'a' be the angle between the grating line directions of the first-dimensional grating and the grating line directions of the second-dimensional grating.

[0029] To be consistent with the case of one-dimensional gratings, the size of the grating vector of a two-dimensional grating is usually defined. ,in, Indicates the magnitude of the grating vector. The magnitude of the grating period component, representing the direction of the grating vector, is exemplified by the above. , .

[0030] Unless otherwise specified, the grating period in the formula for the magnitude of the grating vector of the two-dimensional grating mentioned below is the magnitude of the grating period component in the direction of the grating vector.

[0031] Analysis of the k-vector effect of grating waveguide on light: like Figure 5 As shown, this example illustrates a grating waveguide design where the input grating 2 is a one-dimensional grating and the output grating 4 is a two-dimensional grating. Assume the waveguide substrate 1 lies in the xy plane, and all gratings on the waveguide substrate plane also lie in the xy plane. The input grating has a grating vector. The coupled grating has a grating vector and According to grating theory, the grating vector... (Here, t=1,2,3) is a vector lying in the xy plane, its direction is perpendicular to the direction of the grating lines, and its magnitude is... ,in, This is the grating period. For carrying... The incident ray, acting as a vector, interacts with the grating region of the grating waveguide (coupled-in grating 2 and coupled-out grating 4 in the figure) and manifests as a change in the k-vector of the light. Each interaction between the light and the grating vector increases the k-vector. ,in, , corresponding to the order of action of the grating vector; and because Since the grating vector is an in-plane vector in the xy plane, its effect on the k-vector of light is only manifested as its effect on the xy-plane component of the k-vector of light. (See figure) That is, the incident light normally The vector can be decomposed into z-axis components. and in-plane components of the xy plane The grating is only for effect.

[0032] The K-space representation of light propagation in a homogeneous medium: Light rays in a homogeneous medium can typically be represented and analyzed using a k-space, where the magnitude of the k-vector reflects the speed of light in the homogeneous medium, and the direction of the k-vector usually represents the direction of light propagation. For light rays propagating in a vacuum (or air), the magnitude of its k-vector is... ,here, Let be the wavelength of light in a vacuum (or air). For a wavelength of ... If the light is used Let be the measure of the propagation state of light in air (refractive index 1). Then, all possible propagation states of light constitute the k-space denoted by . ( The size is A sphere with radius , such as Figure 6aAs shown in the figure, The unit vector representing the x-direction component. The unit vector representing the y-direction component. The unit vector representing the z-axis component; each point on the sphere represents a propagation state of light, and the direction of light propagation is the vector direction from the center of the sphere to that point on the surface. Similarly, if we use... This indicates that light travels at a refractive index of 100%. The propagation states of light in a homogeneous medium, and all possible propagation states of light constitute the k-space denoted by . ( The size is A sphere with radius ) as, such as Figure 6b As shown.

[0033] K-space representation of light propagation in a grating waveguide: For example, Figure 7 The diagram shows a schematic representation of the K-space propagation of light in a grating waveguide when the grating waveguide plane is located in the xy plane (focusing only on the in-plane components parallel to the xy plane in k-space). The inner circle represents the projection of the first K-space vector sphere, determined by the air refractive index, onto the grating waveguide plane. This first K-space vector sphere contains all states in which light can propagate in air. The radius of the inner circle is shown in the diagram. ( Size The outer circle represents the refractive index of the waveguide substrate. The projection of the determined second K-space vector sphere onto the grating waveguide plane, where the second K-space vector sphere contains all states in which light can propagate within the waveguide matrix, and the radius of the outer circle is shown in the figure. ( The size is In the diagram, region I represents the propagation of light in air; region III represents the propagation of light in neither air nor at a refractive index of 1. In region II, light propagates within the waveguide substrate medium, meaning there is no propagation state; region II indicates that light cannot propagate in air but can only propagate in wavelengths with a refractive index of 1.5. The light propagates in the waveguide substrate medium, that is, in a medium with a refractive index of . Propagation occurs via total internal reflection in the waveguide substrate medium.

[0034] Figure 8a The diagram shows the K-space propagation of a light beam (composed of incident rays) incident at a small angle into a grating waveguide in a conventional two-dimensional grating waveguide scheme. The inner circle represents the projection of the first K-space vector sphere, determined by the air refractive index, onto the grating waveguide plane. The radius of the inner circle is shown in the diagram. ( Size The outer circle represents the refractive index of the waveguide substrate. The projection of the second K-space vector sphere onto the grating waveguide plane is determined, and the radius of the outer circle is shown in the figure. ( The size is In the diagram, the rectangles represent the in-plane components of the k-vector of the beam within the waveguide plane (dashed rectangles represent the in-plane components of the k-vector of the grating waveguide incoming beam / grating waveguide outgoing beam within the waveguide plane, solid rectangles represent the in-plane components of the k-vector of the beam propagating through total internal reflection within the waveguide matrix of the grating waveguide within the waveguide plane). The grating vector coupled into the grating. and These are the two grating vectors that are coupled out of the grating. and They are equal in size but different in direction. and The vector sum is 0. The in-plane component of the k-vector of any incident ray in the incident beam within the waveguide plane is equal to the grating vector. The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7 (Region II in the image). The in-plane component of the k-vector of any incident ray in the incident beam within the waveguide plane and the grating vector. grating vector The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7 (Region II in the image). The in-plane component of the k-vector of any incident ray in the incident beam within the waveguide plane and the grating vector. grating vector The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7 (Region II in the middle).

[0035] When an incident beam is incident on a grating waveguide at a small angle (e.g., the vertical deflection angle of the projector is less than half the vertical projection field of view of the projector), part of the incident beam will be reflected back to the projector that projected the incident beam, and then reflected again by the projector, thus coupling into the grating waveguide, causing ghosting in waveguide imaging. Therefore, to avoid ghosting in waveguide imaging, current methods use a large angle to incident the beam on the grating waveguide. Figure 8b The diagram shows a K-space design schematic of a conventional two-dimensional grating waveguide scheme when the incident beam is incident at a large angle. The inner circle represents the projection of the first K-space vector sphere, determined by the air refractive index, onto the grating waveguide plane. The radius of the inner circle is shown in the diagram. ( Size The outer circle represents the refractive index of the waveguide substrate. The projection of the second K-space vector sphere onto the grating waveguide plane is determined, and the radius of the outer circle is shown in the figure. ( The size is In the diagram, the rectangles represent the in-plane components of the k-vector of the beam within the waveguide plane (dashed rectangles represent the in-plane components of the k-vector of the grating waveguide incoming beam / grating waveguide incoming beam within the waveguide plane, and solid rectangles represent the in-plane components of the k-vector of the beam propagating through total internal reflection within the waveguide substrate within the waveguide plane). The grating vector coupled into the grating. and These are the two grating vectors that are coupled out of the grating. and They are equal in size but different in direction. and The vector sum is 0. The in-plane component of the k-vector of any incident ray in the incident beam within the waveguide plane is equal to the grating vector. The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7 (Region II in the image). The in-plane component of the k-vector of any incident ray in the incident beam within the waveguide plane and the grating vector. grating vector The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7(Region II in the image). The in-plane component of the k-vector of a portion of the incident ray in the waveguide plane and the grating vector. grating vector The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined by the first K-space vector sphere, is located within the projection region of the grating waveguide plane and outside the projection region of the first K-space vector sphere, as determined by the air refractive index (corresponding to...). Figure 7 (Region II in the waveguide), the in-plane component of the k-vector of the remaining incident rays in the incident beam and the grating vector grating vector The vector and located according to the refractive index of the waveguide substrate ( The second K-space vector sphere, as determined, is projected onto the grating waveguide plane outside its designated region (corresponding to...). Figure 7 (Region III in the grating), which causes the incident beam to pass through the grating vector coupled into the grating. When a portion of the beam that has undergone total internal reflection propagation within the waveguide substrate reaches the decoupled grating, the grating vector of the decoupled grating... The waveguide cannot propagate due to its inability to function, resulting in uneven overall imaging and low optical efficiency.

[0036] To address the aforementioned problems, this invention provides a diffraction grating waveguide, comprising a waveguide substrate, on which a coupling-in grating and a coupling-out grating are disposed. The coupling-out grating is a two-dimensional grating, while the coupling-in grating can be a one-dimensional or two-dimensional grating.

[0037] The coupling grating is used to couple the incident beam into the waveguide substrate for total internal reflection propagation, while the coupling grating is used to perform two-dimensional pupil expansion and coupling imaging of the beam that has propagated by total internal reflection within the waveguide substrate.

[0038] The coupled grating has a coupled grating vector The coupling grating has a first coupling grating vector. Second coupled grating vector .

[0039] First coupling grating vector Second coupled grating vector The vectors have different magnitudes and different directions.

[0040] Coupled grating vector The vector size can be the same as the first coupled grating vector. Or the second coupled grating vector The vectors can be of equal or unequal magnitude. Coupled grating vectors The vector direction and the first coupled grating vector Second coupled-out grating vector The vector directions are not the same.

[0041] Preferably, the coupled grating vector First coupled grating vector and the second coupled grating vector The vectors have unequal magnitudes and different directions. For example, such as... Figure 9 As shown, the coupled grating vector First coupled grating vector and the second coupled grating vector The vectors have different magnitudes and different directions.

[0042] like Figure 9 As shown, the coupled grating vector First coupled grating vector Second coupled grating vector The vector sum is 0. This ensures that the incident beam projected by the projection optical engine passes through the grating waveguide coupled to the grating vector. First coupled grating vector Second coupled grating vector The vector effect will eventually return to the original state, that is, when the projected image of the projector enters the human eye through the grating waveguide for imaging, the grating waveguide display image is guaranteed to be distortion-free and undistorted compared to the projected image of the projector.

[0043] like Figure 9 As shown, any incident ray in the incident beam has an incident vector. The incident vector of the incident ray The vector components and the coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector First coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector First coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

[0044] Among them, the incident vector of the incident ray The vector component is the incident vector of the incident ray. Vector components in the waveguide substrate plane. The first projection region is the first circular projection region on the waveguide substrate plane of the first K-space vector sphere determined according to the refractive index of air. The first K-space vector sphere contains all states in which light can propagate in air, and the radius of the first circular projection region is... , , This represents the wavelength of light in air. The second projection region is the second circular projection region on the waveguide substrate plane of the second K-space vector sphere, determined according to the refractive index of the waveguide substrate. The second K-space vector sphere contains all states in which light can propagate within the waveguide substrate. The radius of the second circular projection region is... , , Indicates the wavelength of light in air. This represents the refractive index of the waveguide substrate. The first center of the first circular projection region coincides with the second center of the second circular projection region.

[0045] The diffraction grating waveguide provided by this invention, based on existing two-dimensional grating waveguide schemes, optimizes the first coupled-out grating vector of the coupled-out grating. Second coupled grating vector Adjustments are made to the first coupled-out grating vector of the coupled-out grating. Second coupled grating vector Set as two vectors of unequal magnitude and different directions, and satisfy the coupling grating vector. First coupled grating vector Second coupled grating vector The vector sum is 0.

[0046] When an incident beam is incident on a grating waveguide at a large angle / small angle, for any incident ray in the incident beam, the incident vector... It can be fully realized: Incident vector of incident ray The vector components and the coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

[0047] Incident vector of incident ray With the coupled grating vector First coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

[0048] Incident vector of incident ray With the coupled grating vector First coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

[0049] The grating waveguide provided by this invention can ensure uniform image display and high luminous efficiency regardless of whether the incident light beam is incident at a small angle or a large angle.

[0050] As a preferred embodiment, for the center incident ray of the incident beam, the present invention further specifies: The incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector First coupled grating vector The vector sum is located at a first set position, which is located outside the first circular projection area and within the second circular projection area.

[0051] The incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector First coupled grating vector The vector sum is located at a second predetermined position, which is located outside the first circular projection area and within the second circular projection area.

[0052] The first and second preset positions are respectively located on the preset circular trajectory (e.g., ...). Figure 10 On the dashed circular trajectory shown, the circular trajectory is set to be outside the first circular projection area and within the second circular projection area.

[0053] The circular trajectory is set to have a third center, which coincides with the first center of the first circular projection area or the second center of the second circular projection area.

[0054] Set the radius of the circular trajectory to be Set the radius of the circular trajectory Satisfy the following formula: (1) (2) (3) in, This indicates the radius of the circular trajectory. This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area. This indicates the wavelength of light in air. It represents the refractive index of the waveguide substrate.

[0055] When the incident vector of the incident ray at the center of the incident beam The vector components and the coupled grating vector First coupled grating vector The vector and the incident vector of the incident ray located on the aforementioned defined circular trajectory, and the center of the incident beam. The vector components and the coupled grating vector First coupled grating vector The vector sum located on the aforementioned circular trajectory can further improve the uniformity of the grating waveguide image display and further improve the light efficiency of the grating waveguide image display.

[0056] When the first and second predetermined positions are respectively located on the aforementioned predetermined circular trajectory, the incident vector of the incident ray passing through the center of the known incident beam... and the coupled grating vector The first output grating vector can be determined according to the following formula. Second coupled grating vector : (4) (5) (6) in, This represents the first output grating vector. This represents the second output grating vector. This represents the incident vector of the central incident ray of a known incident beam. This represents the known coupled-in grating vector. Indicates perpendicular to unit vector, For vectors coefficient, This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area.

[0057] When the incident vector of the central incident ray of the incident beam is known... and the coupled grating vector The first coupled grating vector can be quickly calculated using the above formulas (4)-(6). Second coupled grating vector .

[0058] The present invention also provides an augmented reality device, including a projection optical engine and a diffraction grating waveguide.

[0059] The diffraction grating waveguide adopts the aforementioned diffraction grating waveguide.

[0060] Projection optical engines are used to project incident light beams onto diffraction grating waveguides.

[0061] 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 skilled in the art can still make modifications or equivalent substitutions to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the protection scope of the claims of the present invention pending approval.

Claims

1. A diffraction grating waveguide, characterized in that, The waveguide includes a waveguide substrate, on which a coupling-in grating and a coupling-out grating are disposed, wherein the coupling-out grating is a two-dimensional grating; The coupling grating is used to couple the incident beam into the waveguide substrate for total internal reflection propagation; the coupling grating is used to perform two-dimensional pupil expansion and coupling imaging on the beam propagating in total internal reflection within the waveguide substrate. The coupling grating has a coupling grating vector. The coupled grating has a first coupled grating vector. Second coupled grating vector The first coupled grating vector Second coupled grating vector The vectors have different magnitudes and different directions; The coupled grating vector First coupled grating vector Second coupled grating vector The vector sum is 0; Each incident ray in the incident beam has an incident vector. The incident vector of the incident ray The vector components and the coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector The first coupled grating vector The vector and the incident vector of the incident ray located outside the first projection area and within the second projection area. With the coupled grating vector The first coupled grating vector The vector sum is located outside the first projection area and within the second projection area.

2. The diffraction grating waveguide according to claim 1, characterized in that, The incident vector of the incident light The vector component is the incident vector of the incident ray. Vector components in the waveguide substrate plane; The first projection area is the first circular projection area of ​​the first K space vector sphere determined according to the refractive index of air onto the waveguide substrate plane; The second projection region is the second circular projection region on the waveguide substrate plane of the second K-space vector sphere determined according to the refractive index of the waveguide substrate. The first center of the first circular projection area coincides with the second center of the second circular projection area.

3. The diffraction grating waveguide according to claim 1, characterized in that, The coupled grating vector With the first coupled grating vector The vectors have different magnitudes and different directions; The coupled grating vector With the second coupled grating vector The vectors have different magnitudes and different directions.

4. The diffraction grating waveguide according to claim 1, characterized in that, The coupled grating vector With the first coupled grating vector Or the second coupled grating vector The vectors are of equal magnitude; the coupled grating vectors With the first coupled grating vector Second coupled-out grating vector The vector directions are different.

5. The diffraction grating waveguide according to claim 2, characterized in that, The incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector The first coupled grating vector The vector sum is located at a first predetermined position, which is located outside the first circular projection area and within the second circular projection area; The incident vector of the central incident ray of the incident beam The vector components and the coupled grating vector The first coupled grating vector The vector sum is located at a second set position, which is located outside the first circular projection area and within the second circular projection area.

6. The diffraction grating waveguide according to claim 5, characterized in that, The first and second predetermined positions are respectively located on predetermined circular trajectories; The third center of the defined circular trajectory coincides with either the first or second center, and the radius of the defined circular trajectory satisfies the following formula: in, This indicates the radius of the circular trajectory. This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area.

7. The diffraction grating waveguide according to claim 6, characterized in that, in, This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area. This indicates the wavelength of light in air. It represents the refractive index of the waveguide substrate.

8. The diffraction grating waveguide according to claim 7, characterized in that, When the first and second predetermined positions are respectively located on the predetermined circular trajectory, the first coupled grating vector is determined according to the following formula. Second coupled grating vector : in, This represents the first output grating vector. This represents the second output grating vector. This represents the incident vector of the central incident ray of a known incident beam. This represents the known coupled-in grating vector. Indicates perpendicular to unit vector, This represents the radius of the first circular projection area. This indicates the radius of the second circular projection area.

9. The diffraction grating waveguide according to claim 1, characterized in that, The coupling grating is a one-dimensional grating or a two-dimensional grating.

10. An augmented reality device, characterized in that, Including projection optical engines and diffraction grating waveguides; The diffraction grating waveguide is the diffraction grating waveguide described in any one of claims 1-9; The projection optical engine is used to project an incident beam onto the diffraction grating waveguide.

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