Grating waveguide device for eliminating central bright line and waveguide system

Abstract

The invention provides a grating waveguide device for eliminating a central bright line and a waveguide system, the grating waveguide device comprises a waveguide substrate and a grating structure, and the grating structure is arranged on the waveguide substrate; the grating structure comprises a coupling-in grating, a turning grating and a coupling-out grating, and the coupling-in grating adopts a two-dimensional grating. An incident light beam is coupled into the waveguide substrate through the diffraction effect of the coupling-in grating to serve as a diffraction light beam for total reflection propagation in the waveguide substrate; a first part of diffracted light beams propagated in the waveguide substrate in a total reflection manner firstly enter the turning grating area, continue to be propagated in the total reflection manner through the waveguide substrate under the diffraction action of the turning grating and then enter the coupling-out grating area, and a second part of diffracted light beams propagated in the waveguide substrate in the total reflection manner directly enter the coupling-out grating area; partial light beams in the first partial diffracted light beam and the second partial diffracted light beam are coupled out of the waveguide through the diffraction effect of the coupling-out grating to form waveguide imaging; a waveguide imaging center bright line is eliminated by adjusting a grating structure and utilizing multiple diffraction.

Description

Technical Field

[0001] This invention belongs to the field of augmented reality technology, specifically relating to a grating waveguide device and waveguide system for eliminating a bright center line. 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, among which wearable AR devices, namely AR glasses, offer the most immersive experience. This type of hardware is a simple pair of glasses that guides light into the eye through microstructures on the lens surface. This hardware implementation method is the most convenient and efficient, and is the mainstream technology for AR. The purpose of AR glasses lenses is to guide images from a microdisplay into the eye through the lenses. A grating waveguide solution is a mainstream technical approach. A grating waveguide includes a waveguide substrate, a coupling grating, and a coupling grating. The coupling grating and coupling grating are set on the waveguide substrate. Its basic principle is as follows: Figure 1 As shown, the light output from the optomechanical 1 is coupled into the waveguide substrate 2 by the coupling grating 3. It propagates in the waveguide substrate 2 by total internal reflection. Whenever it encounters the coupling grating 4, a portion of the light is coupled out. The 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 optomechanical 1 can be seen. At the same time, the human eye can also see the real world scene (the dashed line in the direction of the human eye in the figure). The superposition of the two parts can realize the function of augmented reality.

[0004] However, existing grating waveguide imaging suffers from uneven energy distribution across different regions of the imaging area. For example, such as... Figure 2The diagram shows a schematic of an existing grating design for a grating waveguide. The input grating 3 is a one-dimensional grating, and the output grating 4 is a two-dimensional grating. Light emitted from the optomechanical system is diffracted by the input grating and propagates through total internal reflection in the waveguide substrate to the region where the output grating is located. After further diffraction by the output grating, the light is finally coupled out of the eye box by the output waveguide. There are two main diffracted paths for the light to be coupled out within the output grating region. The light beam propagates through total internal reflection in the output grating along the 0th order diffraction direction in the x-direction of the output grating. Each time the total internally reflected light hits the output grating, 1) part of the light is diffracted by the output grating. This diffraction order cancels out the diffraction order of the input grating, causing the light to be coupled out of the waveguide. The remaining light propagates through total internal reflection along the original path until it hits the output grating again, repeating the diffraction coupling process, forming a phenomenon of simultaneous propagation and coupling out. 2) Some light is affected by the -1 (+1) order diffraction in the x-direction of the coupling grating, causing it to change its original downward total internal reflection propagation direction to downward (left-right) total internal reflection. Each time this total internally reflected light hits the coupling grating: some light ① is diffracted and coupled out of the waveguide into the eye box; some light ② continues its original path downward (left-right) total internal reflection until it hits the coupling grating again, repeating the diffraction process; and some light ③, while propagating downward (left-right) total internal reflection, is diffracted upon encountering the grating, changing its original propagation direction to downward total internal reflection. When it hits the coupling grating again, all three diffraction processes are repeated, ultimately resulting in light being continuously coupled out of the waveguide into the eye box for imaging. However, because the 0th order energy diffraction efficiency is usually high, the overall energy coupling efficiency of process 1) is high. This causes a bright line with significantly higher brightness than the sides to appear in the central axis region of the waveguide image seen by the human eye through the eye box, affecting the viewing effect of the waveguide image. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention provides a grating waveguide device and waveguide system for eliminating the center bright line.

[0006] This invention is achieved through the following technical solution:

[0007] This invention provides a grating waveguide device for eliminating a bright center line, the grating waveguide device comprising a waveguide substrate and a grating structure;

[0008] The grating structure is disposed on the waveguide substrate;

[0009] The grating structure includes an input grating, a transition grating, and an output grating, wherein the input grating is a two-dimensional grating;

[0010] The incident beam is coupled into the waveguide substrate by the diffraction of the coupling grating and propagates as a diffracted beam within the waveguide substrate through total internal reflection. The first part of the diffracted beam, which propagates through total internal reflection within the waveguide substrate, first enters the deflection grating region. After being diffracted by the deflection grating, it continues to propagate through total internal reflection within the waveguide substrate and then enters the output grating region. The second part of the diffracted beam, which propagates through total internal reflection within the waveguide substrate, directly enters the output grating region. A portion of the first part of the diffracted beam and a portion of the second part of the diffracted beam, which enter the output grating, are coupled out of the waveguide by the diffraction of the output grating to form waveguide imaging.

[0011] By adjusting the grating structure, multiple diffraction operations are used to eliminate the bright line at the center of the waveguide imaging.

[0012] Furthermore, the folding grating is a one-dimensional grating or a two-dimensional grating.

[0013] Furthermore, the coupled grating is a one-dimensional grating or a two-dimensional grating.

[0014] Furthermore, the folding grating includes a first folding grating and a second folding grating;

[0015] A portion of the first diffracted beam propagating through total internal reflection in the waveguide substrate enters the first inflection grating region, and continues to propagate through total internal reflection in the waveguide substrate after being diffracted by the first inflection grating into the coupling grating region.

[0016] Another portion of the diffracted beam, which propagates through total internal reflection within the waveguide substrate, enters the second inflection grating region. After being diffracted by the second inflection grating, it continues to propagate through total internal reflection within the waveguide substrate and enters the coupling grating region.

[0017] Furthermore, by adjusting the size of the coupling grating, the diffracted beam coupled to the waveguide substrate is diffracted multiple times using the coupling grating to reduce the energy of the second part of the diffracted beam propagating in the waveguide substrate by total internal reflection entering the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

[0018] Furthermore, it also includes a first adjustment grating;

[0019] The first adjustment grating is disposed on the waveguide substrate;

[0020] The first adjustment grating is disposed on the propagation path of the second part of the diffracted beam, which is propagated by total internal reflection within the waveguide substrate, and propagates from the coupling-in grating toward the coupling-out grating;

[0021] The first adjustment grating diffracts the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate multiple times to reduce the energy of the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate into the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

[0022] Furthermore, by adjusting the grating groove parameters or size of the first adjustment grating, the energy of the second part of the diffracted beam propagating through total internal reflection in the waveguide substrate is changed, thereby eliminating the bright line at the center of the waveguide imaging.

[0023] Furthermore, the grating groove parameters of the first adjusting grating are the grating groove depth and / or the grating's aspect ratio.

[0024] Furthermore, it also includes a second adjustment grating;

[0025] The second adjustment grating is disposed on the waveguide substrate;

[0026] The second adjustment grating is disposed on the propagation path of the second part of the diffracted beam that propagates by total internal reflection within the waveguide substrate, and extends from the edge of the coupling grating in the direction toward the coupling grating;

[0027] The second adjustment grating diffracts the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate multiple times to reduce the energy of the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate entering the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

[0028] Furthermore, by adjusting the grating groove parameters or size of the second adjustment grating, the energy of the second part of the diffracted beam propagating through total internal reflection in the waveguide substrate enters the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

[0029] Furthermore, the grating groove parameters of the second adjusting grating are the grating groove depth and / or the grating's aspect ratio.

[0030] Furthermore, by adjusting the size of the folding grating, the first portion of the diffracted beam propagating through total internal reflection in the waveguide substrate is diffracted multiple times using the folding grating to adjust the energy of the first portion of the diffracted beam entering the coupling grating.

[0031] The present invention also provides a waveguide system, including a grating waveguide device;

[0032] The grating waveguide device described above uses the grating waveguide device for eliminating the bright center line.

[0033] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0034] The present invention provides a grating waveguide device for eliminating a bright center line. The grating waveguide device includes a waveguide substrate and a grating structure, wherein the grating structure is disposed on the waveguide substrate. The grating structure includes an input grating, a folding grating, and an output grating, wherein the input grating is a two-dimensional grating. The incident beam is coupled into the waveguide substrate by the diffraction of the coupling grating and propagates as a diffracted beam within the waveguide substrate through total internal reflection. The first part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, first enters the deflection grating region. After being diffracted by the deflection grating, it continues to propagate through total internal reflection within the waveguide substrate and then enters the output grating region. The second part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, directly enters the output grating region. The first part of the diffracted beam and a portion of the second part of the diffracted beam, entering the output grating, are coupled out of the waveguide by the diffraction of the output grating to form a waveguide image. By adjusting the grating structure, multiple diffractions are used to eliminate the bright line at the center of the waveguide image. That is, by setting the above-mentioned grating structure on the waveguide substrate and adjusting the grating structure, problems such as a bright line with significantly higher brightness than the two sides appearing in the central axis region of the waveguide image, thus affecting the observation effect, can be solved. Attached Figure Description

[0035] 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.

[0036] Figure 1 A schematic diagram illustrating the basic principle of the grating waveguide scheme;

[0037] Figure 2 A schematic diagram of an existing grating design for example grating waveguides;

[0038] Figure 3 A schematic diagram of the grating design of the grating waveguide of the present invention, as a first example;

[0039] Figure 4 for Figure 3 A cross-sectional view along the y-axis;

[0040] Figure 5 A schematic diagram of the grating design of the grating waveguide of the present invention, as a second example;

[0041] Figure 6 for Figure 5 A cross-sectional view along the y-axis;

[0042] Figure 7 A schematic diagram of the grating design of the grating waveguide of the present invention, as a third example;

[0043] Figure 8 for Figure 7 A cross-sectional view along the y-axis;

[0044] Figure 9 This is a schematic diagram of the grating design of the grating waveguide of the present invention, which is a fourth example.

[0045] Among them, 1-optical mechanism, 2-waveguide substrate, 3-coupled grating, 4-coupled grating, 5-1-first bend grating, 5-2-second bend grating, 6-first adjustment grating, 7-second adjustment grating. Detailed Implementation

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In this description, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0050] Existing grating waveguide imaging suffers from uneven energy distribution across different regions of the imaging area. For example... Figure 2 As shown, the coupling grating 3 adopts a one-dimensional configuration, and the coupling grating 4 adopts a two-dimensional configuration. When the human eye views the waveguide image in the coupling grating region of the grating waveguide through the eye box, a bright line with significantly higher brightness than the two sides will appear in the central axis region of the waveguide image, affecting the viewing effect of the grating waveguide.

[0051] To address the aforementioned problems, this invention provides a grating waveguide device, comprising a waveguide substrate and a grating structure, wherein the grating structure is disposed on the waveguide substrate. The grating structure includes an input grating, a bend grating, and an output grating, wherein the input grating is a two-dimensional grating.

[0052] The incident beam is coupled into the waveguide substrate by the diffraction of the coupling grating and propagates as a diffracted beam within the waveguide substrate through total internal reflection. The first part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, first enters the deflection grating region. After being diffracted by the deflection grating, it continues to propagate through total internal reflection within the waveguide substrate and then enters the output grating region. The second part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, directly enters the output grating region. The first part of the diffracted beam and a portion of the second part of the diffracted beam, entering the output grating, are coupled out of the waveguide by the diffraction of the output grating to form a waveguide image. By adjusting the above grating structure, the bright line at the center of the waveguide image of the output waveguide is eliminated.

[0053] By adjusting the grating structure described above and utilizing multiple diffraction operations, the bright line at the center of the waveguide image coupled out of the waveguide can be eliminated. For example, the following scheme can be adopted:

[0054] Option 1:

[0055] like Figure 3 As shown, the grating waveguide device includes a waveguide substrate and a grating structure, with the grating structure disposed on the waveguide substrate. The grating structure includes an input grating 3, a first bend grating 5-1, a second bend grating 5-2, and an output grating 4. The input grating 3 is a two-dimensional grating, the first bend grating 5-1 is a one-dimensional grating, the second bend grating 5-2 is a one-dimensional grating, and the output grating 4 is a one-dimensional grating.

[0056] Adjusting the size of the coupling grating 3 allows for multiple diffractions of the diffracted beam into the waveguide substrate, reducing the beam energy of the 0th order diffraction direction along the x-direction of the coupling grating that propagates through total internal reflection into the waveguide substrate and enters the output grating 4, thereby eliminating the bright line at the center of the waveguide imaging.

[0057] Specifically,

[0058] like Figure 3As shown, the incident beam is coupled into the waveguide substrate by the diffraction of the coupling grating 3, and then propagates as a diffracted beam through total internal reflection within the waveguide substrate. The diffracted beam is divided into three parts that propagate to the coupling grating region and then enter the eye box for imaging through the coupling waveguide by the coupling grating 4. Specifically, the first part of the diffracted beam is diffracted downwards by the 0th order diffraction in the x-direction of the coupling grating 3 and propagates through total internal reflection of the waveguide substrate into the coupling grating region. Within the coupling grating region, each time the first part of the diffracted beam hits the coupling grating 4, part of the first part of the diffracted beam is diffracted and coupled out through the waveguide (i.e., beam ①) and enters the eye box, while the other part of the first part of the diffracted beam continues downwards along the original path through total internal reflection of the waveguide substrate until it hits the coupling grating 4 again, repeating the diffraction coupling process. The second part of the diffracted beam, after first-order diffraction in the x-direction of the coupling grating 3, propagates to the lower right through total internal reflection of the waveguide substrate and enters the first transition grating region. Within the first transition grating region, each time the second part of the diffracted beam hits the first transition grating 5-1, part of the second part of the diffracted beam is diffracted, thus changing the direction of total internal reflection propagation to the lower left as the first transition beam entering the coupling grating region. The other part of the second part of the diffracted beam continues to propagate to the lower right along the original path through total internal reflection of the waveguide substrate until it hits the first transition grating 5-1 again, repeating the diffraction transition process. Of these first transition beams entering the coupling grating region, part of the first transition beam propagates through total internal reflection of the waveguide substrate and interacts with the coupling grating, and is coupled out of the waveguide (i.e., beam ②) into the eyebox. The remaining first transition beam continues to propagate through total internal reflection of the waveguide substrate along the original direction and repeats the diffraction coupling process. The third diffracted beam, after being diffracted in the x-direction by the -1st order of the coupling grating 3, propagates along the lower left through total internal reflection of the waveguide substrate and enters the second transition grating region. Within the second transition grating region, each time the third diffracted beam strikes the second transition grating 5-2, part of the third diffracted beam is diffracted, thus changing the direction of total internal reflection propagation and entering the output grating region as the lower right direction. The remaining third diffracted beam continues along the original path, propagating along the lower left through total internal reflection of the waveguide substrate until it strikes the second transition grating 5-2 again, repeating the diffraction transition process. Among these second transition beams entering the output grating region, part of the second transition beam propagates through total internal reflection of the waveguide substrate and interacts with the output grating, being coupled out of the waveguide (i.e., beam ③) and entering the eyebox. The remaining second transition beam continues along the original direction through total internal reflection of the waveguide substrate and repeats the diffraction coupling process.

[0059] It should be noted that when the coupling grating is a two-dimensional grating, similar phenomena will also appear in the coupling grating region. Figure 2 The coupled beam ① in the scheme corresponds to Figure 3 The coupled beam ④ in the middle.

[0060] The incident beam, after being diffracted by the coupling grating 3, is coupled into the waveguide substrate. As a diffracted beam, it propagates along the -1st, +1st, and 0th order diffractions in the x-direction of the coupling grating 3, and finally converges into the output grating through total internal reflection in the waveguide substrate. Since the total light energy of the diffracted beam is constant, compared to... Figure 2 The existing waveguide substrate is configured with a one-dimensional coupling grating and a two-dimensional coupling grating, which reduces the light energy entering the coupling grating through the 0th order diffraction in the x-direction of the coupling grating to a certain extent.

[0061] The length of the coupling grating 3 is extended along the direction close to the output grating 4 to increase the number of diffractions of the diffracted beam into the waveguide substrate on the coupling grating 3. This reduces the energy of the 0th order diffraction direction of the coupling grating 3 in the waveguide substrate that propagates into the output grating 4 by total internal reflection, thereby eliminating the bright line at the center of the waveguide imaging.

[0062] Figure 4 for Figure 3 A cross-sectional view along the y-axis. The incident beam, after being diffracted by the coupling grating 3, is coupled into the waveguide substrate 2 and propagates as a diffracted beam within the waveguide substrate 2 through total internal reflection. Each time it hits the region of the coupling grating 3, 1) part of the beam is diffracted again by the coupling grating 3 and coupled out of the waveguide, 2) the remaining beam continues to propagate through the waveguide substrate 2 through total internal reflection along the original path until it encounters the coupling grating 3 again and repeats the diffraction process. The greater the length of the coupling grating 3 extending towards the coupling grating 4, the more times the diffracted beam entering the waveguide substrate 2 undergoes diffraction by the coupling grating 3, and the less light energy remains that can propagate through total internal reflection within the waveguide substrate 2. Thus, by controlling the length of the coupling grating 3 extending towards the coupling grating 4, the light energy transmitted from the coupling grating 3 to the coupling grating 4 through 0th-order diffraction in the x-direction can be controlled, thereby optimizing, weakening, or even eliminating the bright line problem.

[0063] Option 2:

[0064] like Figure 5 As shown, the grating waveguide device includes a waveguide substrate and a grating structure, with the grating structure disposed on the waveguide substrate. The grating structure includes an input grating 3, a first bend grating 5-1, a second bend grating 5-2, and an output grating 4. The input grating 3 is a two-dimensional grating, the first bend grating 5-1 is a one-dimensional grating, the second bend grating 5-2 is a one-dimensional grating, and the output grating 4 is a one-dimensional grating.

[0065] Based on the above grating structure, a first adjustment grating 6 is added, and the first adjustment grating 6 is disposed on the waveguide substrate.

[0066] The first adjustment grating 6 is positioned on the propagation path of the 0th order diffracted beam in the x direction of the coupled grating 3, which propagates through total internal reflection of the waveguide substrate to the coupled grating 4.

[0067] The first adjustment grating 6 is used to diffract the 0th order diffracted beam in the x direction of the coupled grating multiple times to reduce the energy of the 0th order diffracted beam in the x direction of the coupled grating propagating into the coupled grating 4 through total internal reflection in the waveguide substrate, thereby eliminating the bright line at the center of the waveguide imaging.

[0068] The first adjustment grating here can be a one-dimensional grating or a two-dimensional grating.

[0069] Figure 6 for Figure 5 A cross-sectional view along the y-axis. The 0th-order diffracted beam in the x-direction from the coupling grating 3 enters the first adjustment grating 6 via total internal reflection from the waveguide substrate 2. Each time the beam hits the region of the first adjustment grating 6, 1) a portion of the beam is diffracted again by the first adjustment grating 6 and coupled out of the waveguide, 2) the remaining beam continues to propagate along the original path through total internal reflection from the waveguide substrate 2 until it encounters the first adjustment grating 6 again and repeats the diffraction process. The portion of the beam that leaves the first adjustment grating 6 and is confined to the waveguide substrate 2 propagates through total internal reflection into the coupling grating 4. By repeatedly diffracting the 0th-order diffracted beam of the coupled grating by the first adjustment grating 6, the light energy of the portion of the beam that leaves the first adjustment grating 6 and is bound to the waveguide substrate 2 and propagates into the coupled grating 4 through total internal reflection is reduced. In this way, the light energy transmitted from the coupled grating 3 to the coupled grating 4 through the 0th-order diffraction in the x-direction can be controlled by controlling the length of the first adjustment grating 6 extending in the direction close to the coupled grating 4 or in the direction close to the coupled grating 3, thereby optimizing, weakening or even eliminating the bright line problem.

[0070] Based on this scheme, as a preferred embodiment, the diffraction efficiency of the first adjustment grating can be adjusted by further adjusting the grating groove shape parameters of the first adjustment grating, thereby changing the light energy transmitted from the input grating 3 to the output grating 4 through the 0th order diffraction in the x direction, so that the bright line at the center of the waveguide imaging is eliminated.

[0071] The grating slot parameters here can be the grating slot depth and / or the grating aspect ratio.

[0072] Option 3:

[0073] like Figure 7 As shown, the grating waveguide device includes a waveguide substrate and a grating structure, with the grating structure disposed on the waveguide substrate. The grating structure includes an input grating 3, a first bend grating 5-1, a second bend grating 5-2, and an output grating 4. The input grating 3 is a two-dimensional grating, the first bend grating 5-1 is a one-dimensional grating, the second bend grating 5-2 is a one-dimensional grating, and the output grating 4 is a one-dimensional grating.

[0074] Based on the above grating structure, a second adjustment grating 7 is added, which is disposed in the waveguide substrate.

[0075] The second adjustment grating 7 is positioned on the propagation path of the 0th order diffracted beam in the x direction of the coupled grating 3, which is propagated through the total internal reflection of the waveguide substrate to the coupled grating 4, and extends from the edge of the coupled grating 4 in the direction toward the coupled grating 3.

[0076] The second adjustment grating 7 is used to diffract the 0th order diffracted beam in the x direction of the coupled grating multiple times to reduce the energy of the 0th order diffracted beam in the x direction of the coupled grating propagating into the coupled grating 4 through total internal reflection in the waveguide substrate, thereby eliminating the bright line at the center of the waveguide imaging.

[0077] The second adjustment grating here can be a one-dimensional grating or a two-dimensional grating.

[0078] Figure 8 for Figure 7 A cross-sectional view along the y-axis. The 0th-order diffracted beam in the x-direction from the coupling grating 3 enters the second adjustment grating 7 via total internal reflection of the waveguide substrate 2. Each time the beam hits the region of the second adjustment grating 7, 1) a portion of the beam is diffracted again by the second adjustment grating 7 and coupled out of the waveguide, 2) the remaining beam continues to propagate along the original path through total internal reflection of the waveguide substrate 2 until it encounters the second adjustment grating 7 again and repeats the diffraction process. The portion of the beam that leaves the second adjustment grating 7 and is confined to the waveguide substrate 2 propagates through total internal reflection of the waveguide substrate 2 and enters the coupling grating 4. By using the second adjustment grating 7 to diffract the 0th order diffracted beam of the coupled grating multiple times, the light energy of the portion of the beam that leaves the second adjustment grating 7 and is bound to the waveguide substrate 2 and propagates through the total internal reflection of the waveguide substrate 2 into the coupled grating 4 is reduced. In this way, the light energy transmitted from the coupled grating 3 to the coupled grating 4 through the 0th order diffraction in the x direction can be controlled by controlling the length of the second adjustment grating 7 extending in the direction close to the coupled grating 3, thereby optimizing, weakening or even eliminating the bright line problem.

[0079] Based on this scheme, as a preferred embodiment, the diffraction efficiency of the second adjustment grating can be adjusted by further adjusting the grating groove shape parameters of the second adjustment grating, thereby changing the light energy transmitted from the input grating 3 to the output grating 4 through the 0th order diffraction in the x direction, so that the bright line at the center of the waveguide imaging is eliminated.

[0080] The grating slot parameters here can be the grating slot depth and / or the grating aspect ratio.

[0081] It should be noted that the above schemes 1-3 are not parallel schemes. Those skilled in the art may combine some or all of the above schemes 1-3 according to actual adjustment needs.

[0082] Based on the above scheme, the size of the deflection grating can be further adjusted. The deflection grating is used to diffract the first part of the diffracted beam propagating in the waveguide substrate multiple times to adjust the energy of the first part of the diffracted beam propagating in the waveguide substrate entering the coupling grating, so that the waveguide imaging energy distribution is uniform.

[0083] For example, such as Figure 9 As shown, the length of the folding grating is extended or shortened in the beam diffraction direction of the deflection grating 4. The folding grating is used to diffract the first part of the diffracted beam propagating in the waveguide substrate multiple times to adjust the energy of the first part of the diffracted beam propagating in the waveguide substrate entering the deflection grating, so that the waveguide imaging energy distribution is uniform.

[0084] There are no specific limitations on the grating slot configuration of the aforementioned transition grating. For example, the transition grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combination grating of one-dimensional and two-dimensional gratings.

[0085] There are no specific limitations on the grating slot configuration of the above-mentioned coupling grating. For example, the coupling grating can be a one-dimensional grating, a two-dimensional grating, or a partitioned combination grating of one-dimensional and two-dimensional gratings.

[0086] There are no specific limitations on the design morphology of the grating regions of the above-mentioned coupling grating, turning grating, coupling out grating, first adjustment grating and second adjustment grating. They can adopt shapes such as rectangles, parallelograms, triangles, circles, ellipses or other polygons.

[0087] There are no specific requirements for the grating groove shape of the above-mentioned coupling grating, turning grating, coupling out grating, first adjustment grating and second adjustment grating. They can be rectangular gratings, triangular gratings, oblique trapezoidal gratings, circular gratings, elliptical gratings or other regular or irregular polygonal gratings.

[0088] The number of the above-mentioned coupling grating, turning grating, coupling out grating, first adjustment grating and second adjustment grating is not limited, and can be one or more.

[0089] This invention also provides a waveguide system, including a grating waveguide device; wherein the grating waveguide device employs the aforementioned grating waveguide device for eliminating central bright lines, and the grating waveguide device can adjust the waveguide imaging uniformity performance. For example, an AR glasses lens uses the aforementioned grating waveguide device for eliminating central bright lines.

[0090] 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 grating waveguide device for eliminating a bright center line, characterized in that, The grating waveguide device includes a waveguide substrate and a grating structure; The grating structure is disposed on the waveguide substrate; The grating structure includes an input grating, a transition grating, and an output grating, wherein the input grating is a two-dimensional grating; The incident beam is coupled into the waveguide substrate by the diffraction of the coupling grating and propagates as a diffracted beam within the waveguide substrate through total internal reflection. The first part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, first enters the deflection grating region. After being diffracted by the deflection grating, it continues to propagate through total internal reflection within the waveguide substrate and then enters the output grating region. The second part of the diffracted beam, propagating through total internal reflection within the waveguide substrate, directly enters the output grating region. A portion of the first part of the diffracted beam and a portion of the second part of the diffracted beam, entering the output grating, are coupled out of the waveguide through the diffraction of the output grating to form waveguide imaging. By adjusting the grating structure, multiple diffraction operations are used to eliminate the bright line at the center of the waveguide imaging.

2. The grating waveguide device for eliminating center bright lines according to claim 1, characterized in that, The folding grating is a one-dimensional grating or a two-dimensional grating.

3. The grating waveguide device for eliminating center bright lines according to claim 1, characterized in that, The coupling grating is a one-dimensional grating or a two-dimensional grating.

4. The grating waveguide device for eliminating center bright lines according to claim 1, characterized in that, The folding grating includes a first folding grating and a second folding grating; A portion of the first diffracted beam propagating through total internal reflection in the waveguide substrate enters the first inflection grating region, and continues to propagate through total internal reflection in the waveguide substrate after being diffracted by the first inflection grating into the coupling grating region. Another portion of the diffracted beam, which propagates through total internal reflection within the waveguide substrate, enters the second inflection grating region. After being diffracted by the second inflection grating, it continues to propagate through total internal reflection within the waveguide substrate and enters the coupling grating region.

5. The grating waveguide device for eliminating center bright lines according to any one of claims 1-4, characterized in that, By adjusting the size of the coupling grating, the diffracted beam coupled to the waveguide substrate is diffracted multiple times using the coupling grating to reduce the energy of the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate and enters the output grating, thereby eliminating the bright line at the center of the waveguide imaging.

6. The grating waveguide device for eliminating center bright lines according to any one of claims 1-4, characterized in that, It also includes a first adjustment grating; The first adjustment grating is disposed on the waveguide substrate; The first adjustment grating is disposed on the propagation path of the second part of the diffracted beam, which is propagated by total internal reflection within the waveguide substrate, and propagates from the coupling-in grating toward the coupling-out grating; The first adjustment grating diffracts the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate multiple times to reduce the energy of the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate into the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

7. The grating waveguide device for eliminating center bright lines according to claim 6, characterized in that, By adjusting the grating groove parameters or size of the first adjustment grating, the energy of the second part of the diffracted beam propagating through total internal reflection in the waveguide substrate is changed, thereby eliminating the bright line at the center of the waveguide imaging.

8. The grating waveguide device for eliminating center bright lines according to claim 7, characterized in that, The grating groove parameters of the first adjusting grating are the grating groove depth and / or the grating's aspect ratio.

9. The grating waveguide device for eliminating center bright lines according to any one of claims 1-4, characterized in that, It also includes a second adjustment grating; The second adjustment grating is disposed on the waveguide substrate; The second adjustment grating is disposed on the propagation path of the second part of the diffracted beam that propagates by total internal reflection within the waveguide substrate, and extends from the edge of the coupling grating in the direction toward the coupling grating; The second adjustment grating diffracts the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate multiple times to reduce the energy of the second part of the diffracted beam that propagates through total internal reflection in the waveguide substrate entering the coupling grating, thereby eliminating the bright line at the center of the waveguide imaging.

10. The grating waveguide device for eliminating center bright lines according to claim 9, characterized in that, By adjusting the grating groove parameters or size of the second adjustment grating, the energy of the second part of the diffracted beam propagating through total internal reflection in the waveguide substrate is changed, thereby eliminating the bright line at the center of the waveguide imaging.

11. The grating waveguide device for eliminating center bright lines according to claim 10, characterized in that, The grating groove parameters of the second adjusting grating are the grating groove depth and / or the grating's aspect ratio.

12. The grating waveguide device for eliminating center bright lines according to any one of claims 1-4, characterized in that, The size of the folding grating is adjusted, and the first part of the diffracted beam propagating in the waveguide substrate is diffracted multiple times using the folding grating to adjust the energy of the first part of the diffracted beam propagating in the waveguide substrate entering the coupling grating.

13. A waveguide system, characterized in that, Including grating waveguide devices; The grating waveguide device described herein is the grating waveguide device for eliminating the center bright line as described in any one of claims 1-12.

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