CN114384618B - Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device - Google Patents
Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device Download PDFInfo
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- CN114384618B CN114384618B CN202210289417.9A CN202210289417A CN114384618B CN 114384618 B CN114384618 B CN 114384618B CN 202210289417 A CN202210289417 A CN 202210289417A CN 114384618 B CN114384618 B CN 114384618B
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/18—Diffraction gratings
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/01—Head-up displays
- G02B27/0101—Head-up displays characterised by optical features
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
- G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
- G02B6/0023—Means for improving the coupling-in of light from the light source into the light guide provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
- G02B6/0026—Wavelength selective element, sheet or layer, e.g. filter or grating
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
- G02B6/0033—Means for improving the coupling-out of light from the light guide
- G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
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Abstract
The embodiment of the invention relates to the technical field of optical devices, and discloses a two-dimensional grating and a forming method thereof, an optical waveguide and near-to-eye display equipment, wherein the two-dimensional grating comprises repeating units which are periodically and flatly arranged on the surface of a waveguide sheet along the horizontal direction and the vertical direction, each repeating unit comprises a first concave/convex part and a second concave/convex part which are arranged along a first horizontal line, and a strip part which is arranged along a second horizontal line and is concavely/convexly arranged on the surface of the waveguide sheet, the first concave/convex parts and the second concave/convex parts in two adjacent repeating units in the horizontal direction form a water drop-shaped structure, the strip-shaped structure is limited by a first boundary line and a second boundary line of different curves, the two-dimensional grating is formed on the optical waveguide by etching according to the requirement of light coupling efficiency, the adjustment freedom degree of the two-dimensional grating in the diffraction optical waveguide is improved on the premise of not increasing the processing difficulty, to control the coupling-out efficiency distribution and achieve better exit pupil uniformity and field of view uniformity.
Description
Technical Field
The embodiment of the invention relates to the technical field of optical devices, in particular to a two-dimensional grating and a forming method thereof, an optical waveguide and near-to-eye display equipment.
Background
Augmented Reality (AR) technology is a technology that integrates virtual information with the real world, and the Augmented Reality technology represented by Augmented Reality glasses is beginning to rise in various industries at present, and particularly in the fields of security and industry, the information interaction mode is greatly improved. Currently, optical display schemes in a relatively mature augmented reality technology are mainly divided into a prism scheme, a birdbath scheme, a free-form surface scheme and an optical waveguide (Lightguide) scheme, the first three schemes have large volumes, and limit the application of the schemes in the aspect of intelligent wearing, namely the aspect of augmented reality glasses, and the optical waveguide scheme is the best optical display scheme in the current augmented reality glasses.
The optical waveguide scheme is divided into a geometric waveguide scheme, an embossed grating waveguide scheme and a volume holographic waveguide scheme, wherein the geometric waveguide scheme is to use an array of coated semi-transparent and semi-reflective mirrors to display virtual information, but the field of view and the eye movement range of the scheme are limited, and the array lenses can bring stripe effects to pictures, so the geometric waveguide scheme cannot present the optimal display effect to human eyes. Volume holographic waveguide solutions are currently limited to large scale mass production. The embossed grating waveguide scheme is the most studied technical scheme at present due to the convenience of nano-imprinting, and has the advantages of large field of view and large eye movement range.
The existing scheme path of the embossed grating waveguide mainly comprises a one-dimensional grating-based optical waveguide scheme and a two-dimensional grating-based optical waveguide scheme, wherein the two-dimensional grating waveguide is divided into a coupling-in area and a coupling-out area, and the coupling-out area adopts a two-dimensional grating structure and has the functions of expansion and coupling-out.
In implementing the embodiments of the present invention, the inventors found that at least the following problems exist in the above related art: in the existing optical waveguide scheme based on the two-dimensional grating structure, the two-dimensional grating structure used in the coupling-out area is usually a cylindrical structure and a rhombic structure, and the two structures have fewer adjustable parameters, so that the adjustment of the coupling-out efficiency is not facilitated.
Disclosure of Invention
The embodiment of the application provides a novel two-dimensional grating, a forming method thereof, an optical waveguide and a near-eye display device.
The purpose of the embodiment of the invention is realized by the following technical scheme:
in order to solve the above technical problem, in a first aspect, an embodiment of the present invention provides a two-dimensional grating, including repeating units periodically tiled on a surface of a waveguide sheet in horizontal and vertical directions, where the repeating units include first and second recesses arranged along a first horizontal line, and a strip-shaped portion arranged along a second horizontal line, the first and second recesses being recessed on the surface of the waveguide sheet, the first and second horizontal lines are two virtual lines parallel to the horizontal direction, the first and second recesses are axisymmetrically arranged along a central axis of the repeating unit, the central axis is a virtual axis capable of bisecting the repeating unit and perpendicular to the first and second horizontal lines, and the first and second recesses next to each other in two horizontally adjacent repeating units form a droplet-shaped structure, a plurality of the belt-shaped parts which are continuous in the horizontal direction form a belt-shaped structure which is limited by a first boundary line and a second boundary line, and the first boundary line and the second boundary line are different multi-time curves.
In order to solve the above technical problem, in a second aspect, an embodiment of the present invention provides a two-dimensional grating, including repeating units arranged on a surface of a waveguide sheet in a horizontal direction and a vertical direction, the repeating units include first and second protruding portions arranged along a first horizontal line, and a strip portion arranged along a second horizontal line, the first and second horizontal lines are two virtual lines parallel to the horizontal direction, the first and second protruding portions are arranged in axial symmetry along a central axis of the repeating unit, the central axis is a virtual axis capable of bisecting the repeating unit and perpendicular to the first and second horizontal lines, and the first and second protruding portions adjacent to each other in the horizontal direction form a droplet-shaped structure, a plurality of the belt-shaped parts which are continuous in the horizontal direction form a belt-shaped structure, the belt-shaped structure is limited by a first boundary line and a second boundary line, and the first boundary line and the second boundary line are different multi-time curves.
In some embodiments, within the repeating unit, the first boundary line is a convex-pointed multi-time curve and the second boundary line is a convex-flat multi-time curve.
In some embodiments, within the repeating unit, the first boundary line is a plano-convex multi-time curve and the second boundary line is a pointed-convex multi-time curve.
In some embodiments, the period of the repeating unit in the horizontal direction is 200nm-2 μm.
In some embodiments, the characteristic dimension of the droplet-like structures in the vertical direction is 10nm-2 μm.
In some embodiments, the surface of the repeating unit is plated with a metal oxide film having a thickness of 10nm to 200 nm.
In order to solve the above technical problem, in a third aspect, an embodiment of the present invention provides a method for forming a two-dimensional grating, including: determining an optimization variable of the two-dimensional grating according to the first aspect or the second aspect, wherein the optimization variable comprises: characteristic dimensions of the drop-shaped structures, relative position parameters of the drop-shaped structures and the strip-shaped structures arranged on the surface of the waveguide sheet, and/or a curve surface type of the first boundary line and the second boundary line; and etching on the waveguide sheet according to the optimized variable to form the two-dimensional grating.
In order to solve the foregoing technical problem, in a fourth aspect, an embodiment of the present invention further provides an optical waveguide, including: a waveguide sheet; the coupling structure is formed by one-dimensional gratings and is arranged on the light incident side of the waveguide sheet; a outcoupling structure constituted by a two-dimensional grating as described in the first or second aspect is provided on the light exit side of the waveguide sheet.
In order to solve the above technical problem, in a fifth aspect, an embodiment of the present invention further provides a near-eye display device, including: an optical waveguide as claimed in the fourth aspect.
Compared with the prior art, the invention has the beneficial effects that: in contrast to the state of the art, the embodiments of the present invention provide a novel two-dimensional grating, a method for forming the same, an optical waveguide, and a near-eye display device, wherein the two-dimensional grating includes repeating units arranged on a surface of a waveguide sheet in a horizontal direction and a vertical direction, the repeating units include a first concave/convex portion and a second concave/convex portion arranged along a first horizontal line, and a strip portion arranged along a second horizontal line and concavely/or convexly arranged on a surface of the waveguide sheet, the first concave/convex portion and the second concave/convex portion adjacent to each other in the horizontal direction form a droplet-shaped structure, the strip-shaped structure is defined by a first boundary line and a second boundary line, the first boundary line and the second boundary line are different multiple curves, the two-dimensional grating can be formed on the optical waveguide by etching according to a requirement of light coupling efficiency, on the premise of not increasing the processing difficulty, the adjustment freedom degree of the two-dimensional grating in the diffraction optical waveguide is improved, the coupling-out efficiency distribution can be better controlled, and better exit pupil uniformity and field uniformity are realized.
Drawings
One or more embodiments are illustrated by the accompanying figures in the drawings that correspond thereto and are not to be construed as limiting the embodiments, wherein elements/modules and steps having the same reference numerals are represented by like elements/modules and steps, unless otherwise specified, and the drawings are not to scale.
Fig. 1 is a top view of a two-dimensional grating according to an embodiment of the present invention;
FIG. 2(a) is a top view of a single repeating unit in the two-dimensional grating of FIG. 1;
FIG. 2(b) is a top view of another two-dimensional grating provided in accordance with an embodiment of the present invention;
FIG. 2(c) is a top view of a single repeating unit in the two-dimensional grating shown in FIG. 2 (b);
FIG. 3(a) is a K vector diagram of the two-dimensional grating shown in FIG. 1;
FIG. 3(b) is a graph showing the diffraction efficiency distribution of the two-dimensional grating shown in FIG. 1;
FIG. 4 is a schematic diagram illustrating a top view of a two-dimensional grating according to a second embodiment of the present invention;
FIG. 5(a) is a top view of a single repeating unit in the two-dimensional grating of FIG. 4;
fig. 5(b) is a top view of another two-dimensional grating provided in the second embodiment of the present invention;
FIG. 5(c) is a top view of a single repeating unit in the two-dimensional grating shown in FIG. 5 (b);
FIG. 6(a) is a K vector diagram of the two-dimensional grating shown in FIG. 4;
FIG. 6(b) is a graph showing the diffraction efficiency distribution of the two-dimensional grating shown in FIG. 4;
fig. 7 is a schematic flowchart of a method for forming a two-dimensional grating according to a third embodiment of the present invention;
fig. 8 is a schematic structural diagram of an optical waveguide according to a fourth embodiment of the present invention;
fig. 9 is a schematic structural diagram of a near-eye display device according to a fifth embodiment of the present invention.
Detailed Description
The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that variations and modifications can be made by persons skilled in the art without departing from the spirit of the invention. All falling within the scope of the invention.
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It should be noted that, if not conflicting, various features of the embodiments of the present invention may be combined with each other within the scope of protection of the present application. Additionally, while functional block divisions are performed in apparatus schematics, with logical sequences shown in flowcharts, in some cases, steps shown or described may be performed in sequences other than block divisions in apparatus or flowcharts. Further, the terms "first," "second," and the like, as used herein, do not limit the data and the execution order, but merely distinguish the same items or similar items having substantially the same functions and actions.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
Specifically, the embodiments of the present invention will be further explained with reference to the drawings; it should be understood that in the structural schematic diagram of the two-dimensional grating and its repeating units, the hatched portion in the figure is the grating structure.
Example one
Fig. 1 and 2(a) show a structure of a single repeating unit in the two-dimensional grating shown in fig. 1, where the two-dimensional grating includes repeating units arranged on a surface of a waveguide sheet in a periodic manner along a horizontal direction (a direction indicated by a dotted arrow in fig. 1) and a vertical direction (a direction parallel to a central axis l 3), the repeating units include a first recessed portion a1 and a second recessed portion a2 arranged along a first horizontal line l1, and a strip portion A3 arranged along a second horizontal line l2 and recessed into the surface of the waveguide sheet, and the first horizontal line l1 and the second horizontal line l2 are two virtual lines parallel to the horizontal direction. In the figure, white portions represent projections, and black portions represent depressions.
In this embodiment, the first recessed portion a1 and the second recessed portion a2 are disposed in axial symmetry along a central axis l3 of the repeating unit, the central axis l3 is a virtual axis which can bisect the repeating unit and is perpendicular to the first horizontal line l1 and the second horizontal line l2, and the adjacent first recessed portion a1 and second recessed portion a2 in two horizontally adjacent repeating units form a droplet-shaped structure a.
In the present embodiment, a plurality of the belt-shaped portions a3 continuing in the horizontal direction constitute a belt-shaped structure defined by a first boundary line S1 and a second boundary line S2, and the first boundary line S1 and the second boundary line S2 are different multi-fold curves.
In the example shown in fig. 2(a) of the present embodiment, in the repeating unit, the first boundary line S1 is a multiple-time curve of a pointed convex type, and the second boundary line S2 is a multiple-time curve of a flat convex type. In some other embodiments, please refer to fig. 2(b) and fig. 2(c), fig. 2(b) shows a top view structure of another two-dimensional grating provided in this embodiment, fig. 2(c) shows a structure of a single repeating unit in the two-dimensional grating shown in fig. 2(b), in the repeating unit, the first boundary line S1 may also be a plano-convex multi-time curve, and the second boundary line S2 may be a pointed-convex multi-time curve, specifically, the first boundary line S1 and the second boundary line S2 may be provided in a convex shape according to actual needs, and need not be limited by this embodiment. Preferably, in the examples shown in fig. 2(a) and 2(c), the repeating units are each an axisymmetric pattern having a central axis l3 as an axis of symmetry.
In the example shown in fig. 2 a, the second boundary line S2 (planoconvex type) in the vertical direction (i.e., the direction perpendicular to the dashed arrow in fig. 1 and the direction indicated by the central axis l 3) corresponding to the peak of the first boundary line S1 (planoconvex type) is also at the peak position. In the example shown in fig. 2(c), the first boundary line S1 (planoconvex type) in the vertical direction (i.e., the direction perpendicular to the dashed arrow in fig. 1, the direction indicated by the central axis l 3) corresponding to the peak of the second boundary line S2 (planoconvex type) is also at the peak position. Preferably, the peak of the boundary line of the pointed convex shape and the peak of the boundary line of the planoconvex shape are kept in correspondence, that is, a point on the boundary line of another planoconvex shape in the vertical direction at which the boundary line of the pointed convex shape is at the peak position is also at the peak position.
In some embodiments, the period of the repeating unit in the horizontal direction (the direction indicated by the dashed arrow in FIG. 1) is 200nm-2 μm. In some embodiments, the characteristic dimension of the droplet-shaped structures a in the vertical direction is 10nm-2 μm. In some embodiments, the surface of the repeating unit is plated with a metal oxide filmThe thickness of the metal oxide film is 10nm-200nm, and the material for the film coating can be selected from titanium dioxide (TiO)2) And aluminum oxide (Al)2O3) And the like.
In this embodiment, by adjusting the characteristic size of the droplet-shaped structure a, the relative position parameters of the droplet-shaped structure a and the strip-shaped structure arranged on the surface of the waveguide sheet, and/or the curve surface type of the first boundary line S1 and the second boundary line S2, the formed two-dimensional grating can adjust the K vector of one or more diffraction orders of the incident light, so as to achieve uniform coupling-out efficiency when the light beam propagates in the extended coupling-out region.
Specifically, the two-dimensional grating shown in fig. 1 can realize the adjustment of the K vector of the partial diffraction order shown in fig. 3(a) when the period is 800nmx462 nm; when the light beam propagates in the extended direction in the coupling-out region, the diffraction efficiency distribution in the vector direction of the partial diffraction order is as shown in fig. 3(b), and R0, R1, R2, R3, R4, and R5 in fig. 3(b) correspond to the previous pass order 0, the extended pass order 1, the extended pass order 2, the extended pass order 3, the extended pass order 4, and the return pass order 5 in fig. 3(a), respectively.
It should be noted that in the example shown in fig. 2(a) and 2(c), the repeating units are divided by the case where the boundary lines have peaks and are axisymmetric, and in some other embodiments, the repeating units may be divided by the case where the boundary lines have troughs and are axisymmetric, or divided in other forms, and specifically, the repeating units may be set according to actual needs, and need not be limited to the example shown in fig. 2(a) and 2 (c).
It should be noted that, in this embodiment, one side of the rounded end of the droplet-shaped structure a formed by the first concave portion a1 and the second concave portion a2, which are adjacent to each other in the horizontal direction, is disposed close to the strip-shaped portion A3, and the peaks of the first concave portion a1 and the second concave portion a2 and the strip-shaped portion A3 are not on the same vertical line (that is, the peaks of the droplet-shaped structure a and the strip-shaped structure are disposed offset in the vertical direction). In other embodiments, the arrangement and position of the first recessed portion a1, the second recessed portion a2, and the band portion A3 may be other arrangements, and need not be limited by this embodiment.
Example two
Fig. 4 and 5(a) show a top view structure of a two-dimensional grating provided in this embodiment, and fig. 5(a) shows a structure of a single repeating unit in the two-dimensional grating shown in fig. 4, where the two-dimensional grating includes repeating units arranged on a surface of a waveguide sheet in a periodic manner along a horizontal direction (a direction indicated by a dotted arrow in fig. 4) and a vertical direction (a direction parallel to a central axis l 3), the repeating units include a first protrusion a4 and a second protrusion a5 arranged along a first horizontal line l1, and a strip-shaped portion a6 arranged along a second horizontal line l2 and protruding from the surface of the waveguide sheet, and the first horizontal line l1 and the second horizontal line l2 are two virtual lines parallel to the horizontal direction. In the figure, white portions represent projections, and black portions represent depressions.
In this embodiment, the first protrusion a4 and the second protrusion a5 are disposed in axial symmetry along a central axis l3 of the repeating unit, the central axis l3 is a virtual axis which can bisect the repeating unit and is perpendicular to the first horizontal line l1 and the second horizontal line l2, and the first protrusion a4 and the second protrusion a5 which are adjacent to each other in the horizontal direction form a droplet-shaped structure a.
In the present embodiment, a plurality of the belt-shaped portions a3 continuing in the horizontal direction constitute a belt-shaped structure defined by a first boundary line S1 and a second boundary line S2, and the first boundary line S1 and the second boundary line S2 are different multi-fold curves.
In the example shown in fig. 5(a) of the present embodiment, in the repeating unit, the first boundary line S1 is a multiple-time curve of a pointed convex type, and the second boundary line S2 is a multiple-time curve of a flat convex type. In some other embodiments, please refer to fig. 5(b) and 5(c), fig. 5(b) shows a top view structure of another two-dimensional grating provided in this embodiment, fig. 5(c) shows a structure of a repeating unit in the two-dimensional grating shown in fig. 5(b), in the repeating unit, the first boundary line S1 may be a plano-convex multi-time curve, and the second boundary line S2 may be a pointed-convex multi-time curve, specifically, the first boundary line S1 and the second boundary line S2 may be provided in a convex shape according to actual needs, and the limitation of this embodiment is not required. Preferably, in the examples shown in fig. 5(a) and 5(c), the repeating units are each an axisymmetric pattern having a central axis l3 as an axis of symmetry.
In the example shown in fig. 5 a, the second boundary line S2 (planoconvex type) in the vertical direction (i.e., the direction perpendicular to the dashed arrow in fig. 1, the direction indicated by the central axis l 3) corresponding to the peak of the first boundary line S1 (planoconvex type) is also at the peak position. In the example shown in fig. 5(c), the first boundary line S1 (planoconvex type) in the vertical direction (i.e., the direction perpendicular to the dashed arrow in fig. 1, the direction indicated by the central axis l 3) corresponding to the peak of the second boundary line S2 (planoconvex type) is also at the peak position. Preferably, the peak of the boundary line of the pointed convex shape and the peak of the boundary line of the planoconvex shape are kept in correspondence, that is, a point on the boundary line of another planoconvex shape in the vertical direction at which the boundary line of the pointed convex shape is at the peak position is also at the peak position.
In some embodiments, the period of the repeating unit in the horizontal direction (the direction indicated by the dashed arrow in FIG. 4) is 200nm-2 μm. In some embodiments, the characteristic dimension of the droplet-shaped structures a in the vertical direction is 10nm-2 μm. In some embodiments, the surface of the repeating unit is coated with a metal oxide film having a thickness of 10nm to 200nm, and the coating material may be selected from, for example, titanium dioxide (TiO)2) And aluminum oxide (Al)2O3) And the like.
In this embodiment, by adjusting the characteristic size of the droplet-shaped structure a, the relative position parameters of the droplet-shaped structure a and the strip-shaped structure arranged on the surface of the waveguide sheet, and/or the curve surface type of the first boundary line S1 and the second boundary line S2, the formed two-dimensional grating can adjust the K vector of one or more diffraction orders of the incident light, so as to achieve uniform coupling-out efficiency when the light beam propagates in the extended coupling-out region. Specifically, the two-dimensional grating shown in fig. 4 can realize the adjustment of the K vector of the partial diffraction order shown in fig. 6(a) when the period is 800nmx462 nm; when the light beam propagates in the extended range of the coupling-out region, the diffraction efficiency distribution in the vector direction of the partial diffraction order is as shown in fig. 6(b), and R0, R1, R2, R3, R4, and R5 in fig. 6(b) correspond to the previous pass order 0, the extended pass order 1, the extended pass order 2, the extended pass order 3, the extended pass order 4, and the return pass order 5 in fig. 6(a), respectively.
In the example shown in fig. 5(a) and 5(c), the repeating units are divided in a case where the boundary lines have peaks and are axisymmetric, and in some other embodiments, the repeating units may be divided in a case where the boundary lines have valleys and are axisymmetric, or may be divided in other forms, and specifically, may be set according to actual needs, and need not be limited to the limitations of the embodiments in fig. 5(a) and 5 (c).
It should be noted that, in this embodiment, one side of the rounded end of the droplet-shaped structure a formed by the first convex portion a4 and the second convex portion a5, which are adjacent to each other in the horizontal direction, is disposed close to the band portion a6, and the peaks of the first convex portion a4 and the second convex portion a5 and the peak of the band portion a6 are not on the same vertical line. In other embodiments, the arrangement of the first protrusion a4, the second protrusion a5, and the band a6 may be other arrangements, and is not limited to this embodiment.
EXAMPLE III
Fig. 7 shows a flow of a method for forming a two-dimensional grating according to this embodiment, where the method includes:
step S11: determining the optimized variables of the two-dimensional grating according to the first embodiment or the second embodiment according to the requirement of the light outcoupling efficiency,
wherein the optimization variables include: the characteristic size of the water drop-shaped structure, the relative position parameters of the water drop-shaped structure and the strip-shaped structure arranged on the surface of the waveguide sheet, the height of the water drop-shaped structure and the strip-shaped structure relative to the surface of the waveguide sheet, and/or the curve surface type of the first boundary line and the second boundary line.
It should be understood that the characteristic dimension of the drop-like structure includes the characteristic dimension of the drop-like structure in the horizontal direction, the characteristic dimension of the drop-like structure in the vertical direction; the relative position parameters of the water drop-shaped structures and the strip-shaped structures arranged on the surface of the waveguide sheet comprise the vertical distance between the water drop-shaped structures and the strip-shaped structures, the horizontal distance between two adjacent water drop-shaped structures, the relative position (such as close arrangement or far arrangement) between the round heads of the water drop-shaped structures and the strip-shaped structures, the vertical relative position (such as staggered arrangement or opposite arrangement) between the wave crests of the water drop-shaped structures and the strip-shaped structures, and the like, and the curve surface type represents the curve bending direction, the bending amplitude and the like, for example, the curve surface type can be a pointed convex type, a plane convex type and the like. Exemplarily, referring to fig. 1 and 2(a), fig. 2(b) and 2(c), fig. 4 and 5(a), fig. 5(b) and 5(c), the distance between the droplet-shaped structures a and the ribbon-shaped structures in the vertical direction is d.
Step S12: and etching on the waveguide sheet according to the optimized variable to form the two-dimensional grating.
Specifically, the dimensional parameters in the structure of the two-dimensional grating can be optimized according to the requirement of the diffraction efficiency of the optical waveguide required by a user, so as to obtain the actual manufacturing parameters of the two-dimensional grating, namely the optimized variables of the two-dimensional grating; thus, the recessed portion is etched on the optical waveguide substrate according to the obtained optimized variable to form the desired two-dimensional grating.
For example, the method for forming a two-dimensional grating provided in this embodiment can optimize the dimensional parameters in the structure of the two-dimensional grating in the example shown in fig. 1 according to the requirement of the optical waveguide required by the user for diffraction efficiency as shown in fig. 3(a) and fig. 3(b), so as to obtain the actual manufacturing parameters of the two-dimensional grating, that is, the optimized variables of the two-dimensional grating; thus, the recessed portion, i.e., the black portion in fig. 1 and 2(a), is etched on the optical waveguide substrate according to the obtained optimized variable, so as to form the two-dimensional grating shown in fig. 1 in the first embodiment.
As another example, according to the requirement of the diffraction efficiency of the optical waveguide required by the user as shown in fig. 6(a) and 6(b), the dimensional parameters in the structure of the two-dimensional grating in the example shown in fig. 4 of the second embodiment are optimized, so as to obtain the actual manufacturing parameters of the two-dimensional grating, i.e., the optimized variables of the two-dimensional grating. Thus, the recessed portion, i.e., the black portion in fig. 4 and 5(a), is etched on the optical waveguide substrate according to the obtained optimized variable, so as to form the two-dimensional grating as shown in fig. 4 in example two.
Example four
In this embodiment, an optical waveguide is provided, please refer to fig. 8, which shows a structure of an optical waveguide provided in this embodiment, where the optical waveguide 10 includes: a waveguide sheet 11; a coupling-in structure 12 formed by a one-dimensional grating, disposed on the light incident side of the waveguide sheet 11; a coupling-out structure 13, which is formed by a two-dimensional grating as described in the first or second embodiment, is disposed on the light exit side of the waveguide plate 11.
The incoupling structure 12 may be a rectangular grating, an inclined grating, a trapezoidal grating, a echelle grating, a holographic grating, or another one-dimensional grating, specifically, the incoupling structure 12 may couple the projection light of the optical machine into the waveguide sheet 11 by diffraction and perform total reflection propagation in the direction of the outcoupling structure 13, and may be set according to actual needs.
The coupling-out structure 13 is formed by a two-dimensional grating as described in the first embodiment or the second embodiment, which is easy to process and is beneficial to adjusting the coupling-out efficiency, specifically, referring to the first embodiment or the second embodiment and the drawings thereof, which are not described in detail herein, the coupling-out region 13 can diffuse and propagate light and couple part of the light out of the waveguide substrate 11 into human eyes, so as to realize the extended pupil display.
EXAMPLE five
The present embodiment provides a near-eye display device, please refer to fig. 9, which shows a structure of a near-eye display device provided in the present embodiment, where the near-eye display device 100 includes: the optical waveguide 10 of embodiment four.
In the near-eye display device 100 provided in this embodiment, the optical waveguide 10 adopts the two-dimensional grating shown in the first embodiment or the second embodiment of the present invention as the coupling-out structure, and the two-dimensional grating has more optimized variables, and can perform multi-parameter control to adjust the diffraction efficiency.
The two-dimensional grating comprises repeating units which are periodically and flatly arranged on the surface of a waveguide sheet along the horizontal direction and the vertical direction, wherein each repeating unit comprises a first concave/convex part and a second concave/convex part which are arranged along a first horizontal line, and a strip part which is arranged along a second horizontal line and is concavely/convexly arranged on the surface of the waveguide sheet, the first concave/convex part and the second concave/convex part which are adjacent in the horizontal direction in two adjacent repeating units form a water drop-shaped structure, the strip-shaped structure is defined by a first boundary line and a second boundary line, and the first boundary line and the second boundary line are different multi-time curves. The two-dimensional grating can be formed on the optical waveguide by etching according to the requirement of the light coupling-out efficiency, the adjustment freedom degree of the two-dimensional grating in the diffraction optical waveguide can be improved on the premise of not increasing the processing difficulty, the coupling-out efficiency distribution can be better controlled, and the better exit pupil uniformity and the better view field uniformity are realized.
It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.
Through the above description of the embodiments, it is obvious to those skilled in the art that the embodiments may be implemented by software plus a general hardware platform, and may also be implemented by hardware. It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A two-dimensional grating comprising a repeating unit laid out on a surface of a waveguide plate periodically in a horizontal direction and in a vertical direction, the repeating unit comprising a first recessed portion and a second recessed portion arranged along a first horizontal line, and a stripe portion arranged along a second horizontal line recessed from the surface of the waveguide plate, the first horizontal line and the second horizontal line being two virtual lines parallel to the horizontal direction,
the first concave part and the second concave part are arranged in axial symmetry along a central axis of the repeating unit, the central axis is a virtual axis which can divide the repeating unit into halves and is perpendicular to the first horizontal line and the second horizontal line, the first concave part and the second concave part which are adjacent in the horizontal direction in two repeating units form a water-drop-shaped structure,
a plurality of the belt-shaped parts which are continuous in the horizontal direction form a belt-shaped structure, the belt-shaped structure is limited by a first boundary line and a second boundary line, and the first boundary line and the second boundary line are different multi-time curves.
2. A two-dimensional grating, comprising a repeating unit periodically tiled on a surface of a waveguide sheet in a horizontal direction and a vertical direction, wherein the repeating unit comprises a first protruding portion and a second protruding portion arranged along a first horizontal line, and a strip portion arranged along a second horizontal line and protruding from the surface of the waveguide sheet, the first horizontal line and the second horizontal line are two virtual lines parallel to the horizontal direction,
the first lug boss and the second lug boss are arranged in axial symmetry along a central axis of the repeating unit, the central axis is a virtual axis which can divide the repeating unit into halves and is perpendicular to the first horizontal line and the second horizontal line, the first lug boss and the second lug boss which are adjacent in the horizontal direction in two adjacent repeating units form a water-drop-shaped structure,
a plurality of the belt-shaped parts which are continuous in the horizontal direction form a belt-shaped structure, the belt-shaped structure is limited by a first boundary line and a second boundary line, and the first boundary line and the second boundary line are different multi-time curves.
3. A two-dimensional grating according to claim 1 or 2,
in the repeating unit, the first boundary line is a convex-pointed multi-time curve, and the second boundary line is a convex-flat multi-time curve.
4. A two-dimensional grating according to claim 1 or 2,
in the repeating unit, the first boundary line is a planoconvex multiple-step curve, and the second boundary line is a pointy convexoconvex multiple-step curve.
5. A two-dimensional grating according to claim 1 or 2,
the period of the repeating unit along the horizontal direction is 200nm-2 μm.
6. A two-dimensional grating according to claim 1 or 2,
the characteristic size of the water drop-shaped structure in the vertical direction is 10nm-2 mu m.
7. A two-dimensional grating according to claim 1 or 2,
and a metal oxide film is plated on the surface of the repeating unit, and the thickness of the metal oxide film is 10nm-200 nm.
8. A method of forming a two-dimensional grating, comprising:
determining an optimized variable of the two-dimensional grating according to any one of claims 1-7 according to the requirement for light outcoupling efficiency,
wherein the optimization variables include: characteristic size of the drop-shaped structures, relative position parameters of the drop-shaped structures and the strip-shaped structures arranged on the surface of the waveguide sheet, heights of the drop-shaped structures and the strip-shaped structures sunken or protruded relative to the surface of the waveguide sheet, and/or curved surface shapes of the first boundary line and the second boundary line;
and etching on the waveguide sheet according to the optimized variable to form the two-dimensional grating.
9. An optical waveguide, comprising:
a waveguide sheet;
the coupling structure is formed by one-dimensional gratings and is arranged on the light incident side of the waveguide sheet;
a outcoupling structure constituted by a two-dimensional grating according to any of claims 1 to 7, arranged on the light exit side of said waveguide sheet.
10. A near-eye display device, comprising: the optical waveguide of claim 9.
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| CN202210289417.9A CN114384618B (en) | 2022-03-23 | 2022-03-23 | Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device |
| PCT/CN2022/097624 WO2023178838A1 (en) | 2022-03-23 | 2022-06-08 | Two-dimensional grating and forming method therefor, optical waveguide and near-to-eye display device |
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| CN202210289417.9A CN114384618B (en) | 2022-03-23 | 2022-03-23 | Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device |
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| CN114384618B (en) * | 2022-03-23 | 2022-06-10 | 深圳珑璟光电科技有限公司 | Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device |
| CN115047565B (en) * | 2022-05-13 | 2023-04-07 | 北京驭光科技发展有限公司 | Diffraction light waveguide and display device with same |
| WO2023245188A2 (en) * | 2022-06-17 | 2023-12-21 | The Regents Of The University Of California | Holographic metasurface grating elements for augmented and virtual reality |
| CN115079323A (en) * | 2022-08-24 | 2022-09-20 | 北京亮亮视野科技有限公司 | Two-dimensional coupling-out grating, two-dimensional diffraction optical waveguide, and near-to-eye display device |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015093399A (en) * | 2013-11-11 | 2015-05-18 | セイコーエプソン株式会社 | Transfer die, diffraction grating and optical device using transfer die, projection/depression formation method using transfer die and method for manufacturing diffraction grating using projection/depression formation method |
| CN105612584A (en) * | 2013-10-07 | 2016-05-25 | 西门子医疗有限公司 | Phase contrast X-ray imaging device and phase grating therefor |
| CN106486574A (en) * | 2015-08-27 | 2017-03-08 | 松下知识产权经营株式会社 | Possesses the light-emitting component of photoluminescent layers |
| CN106597658A (en) * | 2017-03-09 | 2017-04-26 | 京东方科技集团股份有限公司 | Display panel and display apparatus |
| WO2019004406A1 (en) * | 2017-06-30 | 2019-01-03 | 大日本印刷株式会社 | Diffraction optical element, manufacturing method therefor, acrylic resin composition for forming diffraction optical element, and illumination device |
| CN109459813A (en) * | 2018-12-26 | 2019-03-12 | 上海鲲游光电科技有限公司 | A kind of planar optical waveguide based on two-dimensional grating |
| CN111512189A (en) * | 2017-10-02 | 2020-08-07 | 瑞士Csem电子显微技术研发中心 | Resonant waveguide grating and application thereof |
| CN113495319A (en) * | 2021-07-30 | 2021-10-12 | Oppo广东移动通信有限公司 | Optical structure and optical device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7059904B2 (en) * | 2018-11-16 | 2022-04-26 | 日本電信電話株式会社 | Wavelength conversion element and its manufacturing method |
| US11061186B2 (en) * | 2018-11-26 | 2021-07-13 | Globalfoundries U.S. Inc. | Waveguide structures |
| CN114384618B (en) * | 2022-03-23 | 2022-06-10 | 深圳珑璟光电科技有限公司 | Two-dimensional grating and forming method thereof, optical waveguide and near-to-eye display device |
-
2022
- 2022-03-23 CN CN202210289417.9A patent/CN114384618B/en active Active
- 2022-06-08 WO PCT/CN2022/097624 patent/WO2023178838A1/en unknown
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105612584A (en) * | 2013-10-07 | 2016-05-25 | 西门子医疗有限公司 | Phase contrast X-ray imaging device and phase grating therefor |
| JP2015093399A (en) * | 2013-11-11 | 2015-05-18 | セイコーエプソン株式会社 | Transfer die, diffraction grating and optical device using transfer die, projection/depression formation method using transfer die and method for manufacturing diffraction grating using projection/depression formation method |
| CN106486574A (en) * | 2015-08-27 | 2017-03-08 | 松下知识产权经营株式会社 | Possesses the light-emitting component of photoluminescent layers |
| CN106597658A (en) * | 2017-03-09 | 2017-04-26 | 京东方科技集团股份有限公司 | Display panel and display apparatus |
| WO2019004406A1 (en) * | 2017-06-30 | 2019-01-03 | 大日本印刷株式会社 | Diffraction optical element, manufacturing method therefor, acrylic resin composition for forming diffraction optical element, and illumination device |
| CN111512189A (en) * | 2017-10-02 | 2020-08-07 | 瑞士Csem电子显微技术研发中心 | Resonant waveguide grating and application thereof |
| CN109459813A (en) * | 2018-12-26 | 2019-03-12 | 上海鲲游光电科技有限公司 | A kind of planar optical waveguide based on two-dimensional grating |
| CN113495319A (en) * | 2021-07-30 | 2021-10-12 | Oppo广东移动通信有限公司 | Optical structure and optical device |
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| WO2023178838A1 (en) | 2023-09-28 |
| CN114384618A (en) | 2022-04-22 |
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