Diffractive waveguide structure

Abstract

The present invention provides a diffraction waveguide structure. The diffraction waveguide structure includes: a waveguide plate; an incoupling region, the incoupling region is arranged on the waveguide plate, and the incoupling region is used to couple light emitted by an external optical machine into the waveguide plate; a turning region; and an outcoupling region, the turning region and the outcoupling region are respectively arranged on two different surfaces of the waveguide plate, and the turning region and the outcoupling region are arranged opposite to each other, the turning region is used to receive light from the incoupling region and perform pupil expansion and steering transmission, and the outcoupling region is used to receive light from the turning region and perform outcoupling; wherein the turning region includes a one-dimensional grating region and a two-dimensional grating region, the one-dimensional grating region includes multiple, at least two sides of the two-dimensional grating region are connected to the one-dimensional grating region, and the symmetry axes of the incoupling region and the two-dimensional grating region in the Y-axis direction are on the same straight line. The present invention solves the problems of poor light energy utilization and poor output uniformity in the diffraction waveguide structure in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of diffraction optical equipment, and in particular to a diffraction waveguide structure. Background Art

[0002] With the continuous development of VR, AR, and MR, the optical devices used in these fields have diversified. Diffraction waveguide structures are an indispensable key technology for AR augmented reality and are currently the mainstream AR display solution. However, diffraction waveguide structures have inherent drawbacks, such as low system efficiency. When light with different field of view angles propagates through the waveguide, its efficiency utilization varies due to the different paths it takes. This leads to uneven light output, poor light energy utilization, and poor output light uniformity.

[0003] That is to say, the diffraction waveguide structure in the prior art has problems of poor light energy utilization and poor output uniformity. Summary of the Invention

[0004] The main purpose of the present invention is to provide a diffraction waveguide structure to solve the problems of poor light energy utilization and poor output uniformity in the diffraction waveguide structure in the prior art.

[0005] In order to achieve the above-mentioned objectives, the present invention provides a diffraction waveguide structure, comprising: a waveguide plate; a coupling-in region, the coupling-in region is arranged on the waveguide plate, and the coupling-in region is used to couple light emitted by an external optical machine into the waveguide plate; a turning region; and a coupling-out region, the turning region and the coupling-out region are respectively arranged on two different surfaces of the waveguide plate, and the turning region and the coupling-out region are arranged opposite to each other, the turning region is used to receive light from the coupling-in region and perform pupil expansion and steering transmission, and the coupling-out region is used to receive light from the turning region and couple out; wherein, the turning region comprises a one-dimensional grating region and a two-dimensional grating region, the one-dimensional grating region comprises a plurality of one-dimensional grating regions, at least two sides of the two-dimensional grating region are connected to the one-dimensional grating region, and the axes of symmetry of the coupling-in region and the two-dimensional grating region in the Y-axis direction are on the same straight line.

[0006] Furthermore, the turning area also includes a connecting grating area, which is located between the one-dimensional grating area and the two-dimensional grating area and is seamlessly connected to the one-dimensional grating area and the two-dimensional grating area.

[0007] Furthermore, the multiple one-dimensional grating regions include a first one-dimensional grating region and a second one-dimensional grating region, there are multiple connected grating regions, and the multiple connected grating regions include a first connected grating region and a second connected grating region. The first connected grating region and the second connected grating region are respectively arranged on a group of opposite sides of the two-dimensional grating region, the first one-dimensional grating region is located on the side of the first connected grating region away from the two-dimensional grating region, and the second one-dimensional grating region is located on the side of the second connected grating region away from the two-dimensional grating region.

[0008] Furthermore, the coupling-in region and the turning region or the coupling-out region are spaced apart on the same side surface of the waveguide plate, and the projection of the coupling-in region on the waveguide plate and the projection of the first connecting grating region and the second connecting grating region on the waveguide plate are located on different sides of the two-dimensional grating region.

[0009] Furthermore, the two-dimensional grating region, the one-dimensional grating region and the connecting grating region all extend in the direction of the Y axis, and the two-dimensional grating region, the one-dimensional grating region and the connecting grating region are spliced ​​to form a turning region.

[0010] Furthermore, the two-dimensional grating region includes grating vectors in at least two directions, the direction of the grating vector K1 of the first one-dimensional grating region is the same as the direction of one grating vector of the two-dimensional grating region, and the direction of the grating vector K2 of the second one-dimensional grating region is the same as the direction of another grating vector of the two-dimensional grating region.

[0011] Furthermore, the angle between the grating vector K1 of the first one-dimensional grating region and the X-axis is 45° or -45°; and / or the angle between the grating vector K2 of the second one-dimensional grating region and the X-axis is 45° or -45°; and / or the grating vector K1 of the first one-dimensional grating region is perpendicular to the grating vector K2 of the second one-dimensional grating region.

[0012] Furthermore, the direction connecting the grating region from the two-dimensional grating region to the one-dimensional grating region includes two-dimensional grating and one-dimensional grating in sequence.

[0013] Furthermore, the direction connecting the grating region from the two-dimensional grating region to the one-dimensional grating region is divided into multiple sub-regions, and the grating structure of each sub-region is different. The gratings in at least three sub-regions close to the two-dimensional grating region among the multiple sub-regions are two-dimensional gratings, and the gratings in at least one sub-region close to the one-dimensional grating region among the multiple sub-regions are one-dimensional gratings.

[0014] Furthermore, the coupling-in region is a one-dimensional grating; and / or the coupling-out region is a one-dimensional grating.

[0015] Furthermore, the grating heights of the two-dimensional grating region and the one-dimensional grating region are both greater than or equal to 30 nm and less than or equal to 200 nm, and the grating height of the two-dimensional grating region is the same as or different from the grating height of the one-dimensional grating region. When the grating height of the two-dimensional grating region is different from the grating height of the one-dimensional grating region, the grating height of the connecting grating region is between the grating height of the two-dimensional grating region and the grating height of the one-dimensional grating region.

[0016] Furthermore, the duty cycles of the two-dimensional grating region along the directions of its two grating vectors are equal, and the duty cycle of the two-dimensional grating region is greater than or equal to 20% and less than or equal to 80%; and / or the duty cycles of the connected grating region along the directions of its two grating vectors are not equal, and the absolute value of the difference in the duty cycles of the connected grating region along the directions of its two grating vectors is greater than or equal to 0% and less than or equal to 30%; the duty cycle of a grating vector direction of the connected grating region is greater than or equal to 20% and less than or equal to 80%; and / or the duty cycle of the one-dimensional grating region along the direction of its grating vector is greater than or equal to 20% and less than or equal to 80%.

[0017] According to the technical solution of the present invention, a diffraction waveguide structure includes a waveguide plate, a coupling-in region, a turning region and a coupling-out region. The coupling-in region is arranged on the waveguide plate, and the coupling-in region is used to couple light emitted by an external optical machine into the waveguide plate; the turning region and the coupling-out region are respectively arranged on two different surfaces of the waveguide plate, and the turning region is arranged opposite to the coupling-out region. The turning region is used to receive light from the coupling-in region and perform pupil expansion and steering transmission, and the coupling-out region is used to receive light from the turning region and couple out; wherein the turning region includes a one-dimensional grating region and a two-dimensional grating region, the one-dimensional grating region includes a plurality of one-dimensional grating regions, at least two sides of the two-dimensional grating region are connected to the one-dimensional grating region, and the axes of symmetry of the coupling-in region and the two-dimensional grating region in the Y-axis direction are on the same straight line.

[0018] By arranging the waveguide, the waveguide provides locations for the in-coupling region, the turning region, and the out-coupling region, which is beneficial for improving the reliability of the in-coupling region, the turning region, and the out-coupling region. The in-coupling region couples most of the light emitted by the external optical engine into the waveguide, which is then transmitted by total reflection toward the turning region. The turning region receives the light transmitted from the in-coupling region and expands and redirects the light, thereby transmitting it toward the out-coupling region. The out-coupling region receives the light from the turning region and couples the light out of the waveguide, where it reaches the human eye for display. The turning region and the out-coupling region are respectively arranged on two different surfaces of the waveguide, and the turning region and the out-coupling region are arranged opposite each other, that is, the projections of the turning region and the out-coupling region on the waveguide overlap. This arrangement facilitates the out-coupling region to receive the light after the pupil expansion and redirection of the turning region, thereby ensuring the efficiency of the out-coupling light. At the same time, this arrangement facilitates compressing the size of the waveguide, thereby achieving miniaturization. The turning region includes a one-dimensional grating region and a two-dimensional grating region. The one-dimensional grating region includes multiple one-dimensional grating regions. The two-dimensional grating region is connected to one-dimensional grating regions on at least two sides. The symmetry axes of the coupling-in region and the two-dimensional grating region in the Y-axis direction are on the same straight line. This configuration enables the one-dimensional grating region and the two-dimensional grating region in the turning region to receive light transmitted from the coupling-in region, expand the pupil and redirect the light so that it meets the outcoupling conditions and is coupled out by the outcoupling region. By connecting one-dimensional grating regions on at least two sides of the two-dimensional grating region, the one-dimensional grating region can collect a large amount of light and change the energy ratio between the various light paths while ensuring that the optical path remains unchanged, achieving a uniform outcoupling effect, thereby improving the outcoupling uniformity of the diffraction waveguide structure. At the same time, the waste of light in the coupling-in region is avoided, allowing the turning region to receive most of the light transmitted from the coupling-in region, improving the light energy utilization rate in the waveguide plate, and thus improving the display efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0020] Figure 1 A schematic diagram showing two surfaces of a diffractive waveguide structure according to an optional embodiment of the present invention;

[0021] Figure 2 Shown Figure 1 A schematic structural diagram of the first connection grating region in FIG.

[0022] Figure 3 Shown Figure 1 Schematic diagram of the structure of the second connected grating area.

[0023] The above drawings include the following reference numerals:

[0024] 10. Coupling region; 21. Two-dimensional grating region; 22. First one-dimensional grating region; 23. Second one-dimensional grating region; 24. First connecting grating region; 25. Second connecting grating region; 30. Outcoupling region. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0027] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity direction; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above directional words are not used to limit the present invention.

[0028] With the development of science and technology, AR (augmented reality) headsets or in-vehicle HUDs have become a current research hotspot and have gradually become part of people's daily lives. Diffraction waveguide structures are currently a mainstream AR design solution and have attracted widespread attention due to their compact size. However, they also have inherent drawbacks, including low system efficiency, poor angular uniformity, and poor eyebox uniformity, which seriously restrict their application in AR devices. This application proposes a diffraction waveguide structure that improves the optical efficiency of the waveguide. While maintaining the same optical path, it changes the energy distribution between the optical paths to improve outcoupling uniformity.

[0029] In order to solve the problems of poor light energy utilization and poor output uniformity in the diffraction waveguide structure in the prior art, the present invention provides a diffraction waveguide structure.

[0030] like Figures 1 to 3 As shown, the diffraction waveguide structure includes a waveguide plate, a coupling-in region 10, a turning region and a coupling-out region 30. The coupling-in region 10 is arranged on the waveguide plate, and the coupling-in region 10 is used to couple the light emitted by the external optical machine into the waveguide plate; the turning region and the coupling-out region 30 are respectively arranged on two different surfaces of the waveguide plate, and the turning region is arranged opposite to the coupling-out region 30. The turning region is used to receive the light from the coupling-in region 10 and perform pupil expansion and steering transmission, and the coupling-out region 30 is used to receive the light from the turning region and couple out; wherein, the turning region includes a one-dimensional grating region and a two-dimensional grating region 21, and the one-dimensional grating region includes multiple, and at least two sides of the two-dimensional grating region 21 are connected to a one-dimensional grating region, and the symmetry axes of the coupling-in region 10 and the two-dimensional grating region 21 in the Y-axis direction are on the same straight line.

[0031] By disposing the waveguide, the waveguide provides locations for the incoupling region 10, the turning region, and the outcoupling region 30. This improves the reliability of the incoupling region 10, the turning region, and the outcoupling region 30. It also facilitates the incoupling region 10 coupling most of the light emitted by the external optical engine into the waveguide, which then undergoes total internal reflection transmission toward the turning region. The turning region receives the light transmitted from the incoupling region 10 and dilates and redirects the light, thereby transmitting it toward the outcoupling region 30. The outcoupling region 30 receives the light from the turning region and couples it out of the waveguide, where it reaches the human eye for display. The turning region and the outcoupling region 30 are disposed on two different surfaces of the waveguide, and the turning region and the outcoupling region 30 are disposed opposite each other, meaning that their projections on the waveguide overlap. This arrangement facilitates the outcoupling region 30 receiving the light dilated and redirected by the turning region, thereby ensuring the efficiency of the outcoupling light. Furthermore, this arrangement facilitates compressing the size of the waveguide, thereby achieving miniaturization. The turning region includes a one-dimensional grating region and a two-dimensional grating region 21. The one-dimensional grating region includes multiple one-dimensional grating regions. At least two sides of the two-dimensional grating region 21 are connected to one-dimensional grating regions. The symmetry axes of the coupling-in region 10 and the two-dimensional grating region 21 in the Y-axis direction are on the same straight line. This configuration enables the one-dimensional grating region and the two-dimensional grating region 21 in the turning region to both receive light transmitted from the coupling-in region 10, expand the pupil and redirect the light so that it meets the outcoupling conditions and is coupled out by the outcoupling region 30. By connecting the one-dimensional grating region to at least two sides of the two-dimensional grating region 21, the one-dimensional grating region can collect a large amount of light and change the energy ratio between the various light paths while ensuring that the optical path remains unchanged, achieving a uniform outcoupling effect, thereby improving the outcoupling uniformity of the diffraction waveguide structure. At the same time, the waste of light in the coupling-in region 10 is avoided, allowing the turning region to receive most of the light transmitted from the coupling-in region 10, improving the light energy utilization rate in the waveguide plate, and thus improving the display efficiency.

[0032] Specifically, the transition region also includes a connecting grating region, which is located between the one-dimensional grating region and the two-dimensional grating region 21 and seamlessly connected to the one-dimensional grating region and the two-dimensional grating region 21. The connecting grating region is used to connect the one-dimensional grating region and the two-dimensional grating region 21. By providing the connecting grating region, the energy ratio between the optical paths is changed while the direction of the optical path remains unchanged, thereby improving the coupling uniformity.

[0033] like Figure 1As shown, the plurality of one-dimensional grating regions include a first one-dimensional grating region 22 and a second one-dimensional grating region 23. There are a plurality of connected grating regions, including a first connected grating region 24 and a second connected grating region 25. The two-dimensional grating region 21 is disposed at a position corresponding to the coupling region 10. The first connected grating region 24 and the second connected grating region 25 are respectively disposed on two opposite sides of the two-dimensional grating region 21, i.e., the left and right sides. The first one-dimensional grating region 22 is located on the side of the first connected grating region 24 away from the two-dimensional grating region 21, and the second one-dimensional grating region 23 is located on the side of the second connected grating region 25 away from the two-dimensional grating region 21. In other words, the first one-dimensional grating region 22, the first connected grating region 24, the two-dimensional grating region 21, the second connected grating region 25, and the second one-dimensional grating region 23 are sequentially arranged from left to right along the X-axis and are connected to each other.

[0034] In the specific embodiments of this application, Figure 1 As shown, the coupling-in region 10 and the turning region are spaced apart on the same side surface of the waveguide plate, and the coupling-out region 30 is spaced apart on the other side surface of the waveguide plate; however, in other optional embodiments of the present application, the coupling-in region 10 and the coupling-out region 30 can also be spaced apart and disposed on the same side surface of the waveguide plate, and it is only necessary to ensure that the turning region and the coupling-out region 30 are respectively disposed on two different surfaces of the waveguide plate. This can effectively utilize the space on the surface of the waveguide plate and reduce the area occupied by the grating, thereby making the waveguide plate smaller and thinner. The projection of the coupling-in region 10 on the waveguide plate and the projection of the first connecting grating region 24 and the second connecting grating region 25 on the waveguide plate are located on different sides of the two-dimensional grating region 21, as shown in FIG. Figure 1 As shown, the coupling region 10 is located above the two-dimensional grating region 21 and is spaced apart. The first connecting grating region 24 and the second connecting grating region 25 are located on the left and right sides of the two-dimensional grating region 21 respectively and are connected.

[0035] like Figure 1 As shown, the two-dimensional grating region 21, the one-dimensional grating region, and the connecting grating region are all strip-shaped. The strip-shaped two-dimensional grating region 21, the one-dimensional grating region, and the connecting grating region all extend along the Y-axis. The two-dimensional grating region 21, the one-dimensional grating region, and the connecting grating region are spliced ​​together to form a whole turning region. In this application, the turning region on the waveguide plate has a trapezoidal shape. The two sides of the turning region facing the coupling region 10 and away from the coupling region 10 are flush.

[0036] like Figure 1As shown, the two-dimensional grating region 21 is a rectangular grating arranged in a rectangular array, preferably a square grating. The two-dimensional grating region 21 includes at least two directional grating vectors, and the two directional grating vectors of the two-dimensional grating region 21 are perpendicular to each other. The direction of the grating vector K1 of the first one-dimensional grating region 22 is the same as the direction of one grating vector of the two-dimensional grating region 21, and the direction of the grating vector K2 of the second one-dimensional grating region 23 is the same as the direction of another grating vector of the two-dimensional grating region 21. The grating vector K1 of the first one-dimensional grating region 22 is perpendicular to the grating vector K2 of the second one-dimensional grating region 23. It should be noted that the grating vector K1 of the first one-dimensional grating region 22 is perpendicular to the grating line direction of the first one-dimensional grating region 22, and the grating vector K2 of the second one-dimensional grating region 23 is perpendicular to the grating line direction of the second one-dimensional grating region 23. In other words, the two-dimensional grating region 21 includes two mutually perpendicular grating lines. The grating line direction of the first one-dimensional grating region 22 is the same as one grating line direction of the two-dimensional grating region 21, and the grating line direction of the second one-dimensional grating region 23 is the same as another grating line direction of the two-dimensional grating region 21. The grating line direction of the first one-dimensional grating region 22 is perpendicular to the grating line direction of the second one-dimensional grating region 23. This arrangement facilitates matching between the one-dimensional grating region and the two-dimensional grating region 21, while ensuring that the one-dimensional grating region only has a grating vector in one direction, discarding the grating vector in the other direction. This selectively enhances diffraction in one direction and discards diffraction in another direction, improving light energy utilization and thereby improving optical efficiency.

[0037] Specifically, the angle between the grating vector K1 of the first one-dimensional grating region 22 and the X-axis is 45° or -45°; the angle between the grating vector K2 of the second one-dimensional grating region 23 and the X-axis is 45° or -45°, and the angle between K1 and K2 is 90°. This configuration constrains the grating vector directions of the first one-dimensional grating region 22 and the second one-dimensional grating region 23, enhancing the diffraction transmission of light in the grating vector directions of the first one-dimensional grating region 22 and the second one-dimensional grating region 23, thereby improving light energy utilization.

[0038] Specifically, the direction connecting the grating regions from the two-dimensional grating region 21 to the one-dimensional grating region includes two-dimensional gratings and one-dimensional gratings, respectively. The two-dimensional grating can be a rectangular grating. By gradually changing from a rectangular grating to a linear one-dimensional grating, the diffraction efficiency in one direction can be gradually enhanced while the diffraction efficiency in another direction can be gradually suppressed. By gradually changing the grating shape in the connecting grating region, compared to abrupt shape modulation, the energy in the eye box can be prevented from changing suddenly, thereby improving the uniformity of the output light.

[0039] Specifically, the direction connecting the grating area from the two-dimensional grating area 21 to the one-dimensional grating area is divided into multiple sub-areas, and the grating structure of each sub-area is different. The gratings in at least three sub-areas close to the two-dimensional grating area 21 among the multiple sub-areas are two-dimensional gratings, and the gratings in at least one sub-area close to the one-dimensional grating area among the multiple sub-areas are one-dimensional gratings.

[0040] like Figure 2 As shown, the first connecting grating region 24 is divided into five sub-regions from the two-dimensional grating region 21 to the first one-dimensional grating region 22. The five sub-regions are all strip-shaped. The five sub-regions are, in order, a square grating, a rectangular grating, a long rectangular grating, a long rectangular grating close to a one-dimensional line grating, and a one-dimensional line grating in the direction away from the two-dimensional grating region 21. The K vectors of the five sub-regions change as shown in the figure. The K vectors of the five sub-regions gradually change from two mutually perpendicular directions to a single direction in the direction away from the two-dimensional grating region 21. The grating vector direction of a sub-region close to the first one-dimensional grating region 22 is the same as the grating vector direction of the first one-dimensional grating region 22, thereby achieving a progressive connection with the first one-dimensional grating region 22.

[0041] like Figure 3 As shown, the second connecting grating region 25 is divided into five sub-regions from the two-dimensional grating region 21 to the second one-dimensional grating region 23. The five sub-regions are all strip-shaped. The five sub-regions are, in order, a square grating, a rectangular grating, a long rectangular grating, a long rectangular grating close to a one-dimensional line grating, and a one-dimensional line grating in the direction away from the two-dimensional grating region 21. The K vectors of the five sub-regions change as shown in the figure. The K vectors of the five sub-regions gradually change from two mutually perpendicular directions to a single direction in the direction away from the two-dimensional grating region 21. The grating vector direction of a sub-region near the second one-dimensional grating region 23 is the same as the grating vector direction of the second one-dimensional grating region 23, thereby achieving a progressive connection with the second one-dimensional grating region 23.

[0042] Specifically, the coupling-in region 10 is a one-dimensional grating; and the coupling-out region 30 is a one-dimensional grating.

[0043] Specifically, the gratings of the two-dimensional grating region 21 are cylindrical and symmetrically arranged along the Y-axis. The projection of the cylindrical grating on the waveguide plate can be a square or a cross. The grating heights of the two-dimensional grating region 21 and the one-dimensional grating region are both greater than or equal to 30 nm and less than or equal to 200 nm. The grating height of the two-dimensional grating region 21 can be the same as or different from the grating height of the one-dimensional grating region. When the grating height of the two-dimensional grating region 21 is different from the grating height of the one-dimensional grating region, the grating height of the connecting grating region is between the grating heights of the two-dimensional grating region 21 and the one-dimensional grating region.

[0044] Specifically, the duty cycles of the two-dimensional grating region 21 along the directions of its two grating vectors are equal, and the duty cycle of the two-dimensional grating region 21 is greater than or equal to 20% and less than or equal to 80%; the duty cycles of the connected grating region along the directions of its two grating vectors are not equal, and the absolute value of the difference in the duty cycles of the connected grating region along the directions of its two grating vectors is greater than or equal to 0% and less than or equal to 30%; the duty cycle of a grating vector direction of the connected grating region is greater than or equal to 20% and less than or equal to 80%; the duty cycle of the one-dimensional grating region along the direction of its grating vector is greater than or equal to 20% and less than or equal to 80%.

[0045] like Figure 1 As shown, in the specific embodiment of the present application, the duty cycles of the first one-dimensional grating region 22 and the second one-dimensional grating region 23 are the same, both 20%; the duty cycles of the two-dimensional grating region 21 along the directions of its two grating vectors are both 50%.

[0046] like Figure 2 As shown, in the first connected grating area 24, the duty cycles in the Ka1 direction and the Ka2 direction are the same, both 50%; the absolute value of the duty cycle difference between the Kb1 direction and the Kb2 direction is in the range of 0%-30%, specifically 20%; the duty cycle difference between the Kc1 direction and the Kc2 direction is in the range of 0%-30%, specifically 30%; the duty cycle difference between the Kd1 direction and the Kd2 direction is in the range of 0%-30%, specifically 10%; the duty cycle in the Ke direction is 20%.

[0047] like Figure 3 As shown, in the second connected grating area 25, the duty cycles of the Kf1 direction and the Kf2 direction are the same, both 50%; the absolute value of the difference in duty cycle between the Kg1 direction and the Kg2 direction is in the range of 0%-30%, specifically 20%; the difference in duty cycle between the Kh1 direction and the Kh2 direction is in the range of 0%-30%, specifically 30%; the difference in duty cycle between the Ki1 direction and the Ki2 direction is in the range of 0%-30%, specifically 10%; the duty cycle of the Kj direction is 20%.

[0048] It should be noted that the diffraction waveguide structure of the present application also includes an optical machine, which is arranged outside the waveguide plate, and the optical machine is arranged corresponding to the coupling-in area 10, so that the image light emitted by the optical machine can be coupled into the waveguide plate by the coupling-in area 10. The optical machine can be a self-luminous active device, such as a micro-OLED or micro-LED, or a liquid crystal display that requires external light source illumination, including a transmissive LCD and a reflective LCOS, as well as a digital micromirror array DMD based on micro-electromechanical system MEMS technology, that is, the core of DLP and a laser beam scanner LBS, etc. The above-mentioned optical machine can provide monochrome or color image light source information, and the size and shape of the light source must match the size and shape of the coupling-in area 10. For example, an optical machine with a circular coupling port must match a circular coupling-in area 10. Different types of optical machines are selected according to actual equipment requirements to achieve the best performance of the waveguide structure.

[0049] Obviously, the embodiments described above are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0050] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, tasks, devices, components and / or combinations thereof.

[0051] It should be noted that the terms "first," "second," and the like in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0052] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A diffraction waveguide structure, characterized in that: include: Waveguide; A coupling-in region (10), the coupling-in region (10) being arranged on the waveguide plate, and the coupling-in region (10) being used to couple light emitted by an external optical machine into the waveguide plate; turning area; An outcoupling region (30), wherein the turning region and the outcoupling region (30) are respectively arranged on two different surfaces of the waveguide plate, and the turning region is arranged opposite to the outcoupling region (30), the turning region is used to receive light from the coupling-in region (10) and perform pupil expansion and steering transmission, and the outcoupling region (30) is used to receive light from the turning region and perform outcoupling; The turning region includes a one-dimensional grating region and a two-dimensional grating region (21), the one-dimensional grating region includes a plurality of regions, at least two sides of the two-dimensional grating region (21) are connected to the one-dimensional grating region, and the symmetry axes of the coupling region (10) and the two-dimensional grating region (21) in the Y-axis direction are on the same straight line.

2. The diffraction waveguide structure according to claim 1, wherein: The turning region further comprises a connecting grating region, wherein the connecting grating region is located between the one-dimensional grating region and the two-dimensional grating region (21) and is seamlessly connected to the one-dimensional grating region and the two-dimensional grating region (21).

3. The diffraction waveguide structure according to claim 2, wherein: The plurality of one-dimensional grating regions include a first one-dimensional grating region (22) and a second one-dimensional grating region (23); the plurality of connected grating regions include a first connected grating region (24) and a second connected grating region (25); the first connected grating region (24) and the second connected grating region (25) are respectively arranged on two opposite sides of a group of the two-dimensional grating region (21); the first one-dimensional grating region (22) is located on a side of the first connected grating region (24) away from the two-dimensional grating region (21); and the second one-dimensional grating region (23) is located on a side of the second connected grating region (25) away from the two-dimensional grating region (21).

4. The diffraction waveguide structure according to claim 3, wherein: The coupling-in region (10) and the turning region or the coupling-out region (30) are arranged at intervals on the same side surface of the waveguide plate, and the projection of the coupling-in region (10) on the waveguide plate and the projections of the first connecting grating region (24) and the second connecting grating region (25) on the waveguide plate are located on different sides of the two-dimensional grating region (21).

5. The diffraction waveguide structure according to claim 2, wherein: The two-dimensional grating region (21), the one-dimensional grating region and the connecting grating region all extend in the direction of the Y axis, and the two-dimensional grating region (21), the one-dimensional grating region and the connecting grating region are spliced ​​to form the turning region.

6. The diffraction waveguide structure according to claim 3, characterized in that: The two-dimensional grating region (21) includes grating vectors in at least two directions, the direction of the grating vector K1 of the first one-dimensional grating region (22) is the same as the direction of one grating vector of the two-dimensional grating region (21), and the direction of the grating vector K2 of the second one-dimensional grating region (23) is the same as the direction of another grating vector of the two-dimensional grating region (21).

7. The diffraction waveguide structure according to claim 3, wherein: The angle between the grating vector K1 of the first one-dimensional grating region (22) and the X-axis is 45° or -45°; and / or The angle between the grating vector K2 of the second one-dimensional grating region (23) and the X-axis is 45° or -45°; and / or The grating vector K1 of the first one-dimensional grating region (22) is perpendicular to the grating vector K2 of the second one-dimensional grating region (23).

8. The diffraction waveguide structure according to claim 2, wherein: The direction of the connecting grating area from the two-dimensional grating area (21) to the one-dimensional grating area includes a two-dimensional grating and a one-dimensional grating in sequence.

9. The diffraction waveguide structure according to claim 2, wherein: The connecting grating region is divided into a plurality of sub-regions in a direction from the two-dimensional grating region (21) to the one-dimensional grating region, and the grating structure of each sub-region is different. The gratings in at least three of the multiple sub-regions close to the two-dimensional grating region (21) are two-dimensional gratings, and the grating in at least one of the multiple sub-regions close to the one-dimensional grating region is a one-dimensional grating.

10. The diffraction waveguide structure according to any one of claims 1 to 9, characterized in that: The coupling-in region (10) is a one-dimensional grating; and / or The outcoupling region (30) is a one-dimensional grating.

11. The diffraction waveguide structure according to claim 2, wherein: The grating heights of the two-dimensional grating region (21) and the one-dimensional grating region are both greater than or equal to 30 nm and less than or equal to 200 nm. The grating height of the two-dimensional grating region (21) is the same as or different from the grating height of the one-dimensional grating region. When the grating height of the two-dimensional grating region (21) is different from the grating height of the one-dimensional grating region, the grating height of the connecting grating region is between the grating height of the two-dimensional grating region (21) and the grating height of the one-dimensional grating region.

12. The diffraction waveguide structure according to claim 2, wherein: The duty cycle of the two-dimensional grating region (21) along the directions of its two grating vectors is equal, and the duty cycle of the two-dimensional grating region (21) is greater than or equal to 20% and less than or equal to 80%; and / or The duty cycles of the connected grating region along the directions of its two grating vectors are not equal, and the absolute value of the difference between the duty cycles of the connected grating region along the directions of its two grating vectors is greater than or equal to 0% and less than or equal to 30%; the duty cycle of one grating vector direction of the connected grating region is greater than or equal to 20% and less than or equal to 80%; and / or The duty cycle of the one-dimensional grating region along the grating vector direction thereof is greater than or equal to 20% and less than or equal to 80%.

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