WO2022048502A1 - 用于ar设备的光波导装置及其制造方法和ar设备 - Google Patents

用于ar设备的光波导装置及其制造方法和ar设备 Download PDF

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WO2022048502A1
WO2022048502A1 PCT/CN2021/115048 CN2021115048W WO2022048502A1 WO 2022048502 A1 WO2022048502 A1 WO 2022048502A1 CN 2021115048 W CN2021115048 W CN 2021115048W WO 2022048502 A1 WO2022048502 A1 WO 2022048502A1
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Prior art keywords
grating
optical waveguide
coupling
element array
waveguide device
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PCT/CN2021/115048
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English (en)
French (fr)
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徐钦锋
马珂奇
杜佳玮
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宁波舜宇光电信息有限公司
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Publication of WO2022048502A1 publication Critical patent/WO2022048502A1/zh

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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
    • 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
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/18—Diffraction gratings
    • G02B5/1814—Diffraction gratings structurally combined with one or more further optical elements, e.g. lenses, mirrors, prisms or other diffraction gratings
    • 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
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • 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
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/124—Geodesic lenses or integrated gratings

Definitions

  • Optical waveguide sheet is a key core component in the new generation of Augmented Reality (AR) technology. It combines the principle of total reflection waveguide with diffractive elements to replicate the extended exit pupil in the imaging system. , small size, light weight and other advantages, it has become an inevitable trend of AR technology development.
  • AR Augmented Reality
  • the typical optical waveguide technology is to project the image light source from the microdisplay into the incident grating area of the optical waveguide sheet through the projection lens, which is captured by the optical waveguide sheet, totally reflected and transmitted to the second grating area, and then is diffracted and turned by 90°.
  • the transmitted light continues to move forward in total reflection along the original direction, and is diffracted by the turning grating each time to realize one-dimensional expansion in the first direction.
  • the two one-dimensional surface relief gratings can be replaced by a two-dimensional surface relief grating, which is used to directly realize the two-dimensional expansion and out-coupling of light.
  • the columnar structure of the two-dimensional surface relief grating in the prior art solution is limited to the arrangement of an equilateral triangular array, which limits the degree of freedom of grating design, and the horizontal field of view is small.
  • the present invention provides an optical waveguide device for an AR device, a manufacturing method thereof, and an AR device, so as to solve or at least alleviate one or more of the above problems and other problems.
  • an optical waveguide device for an AR device which includes an optical waveguide substrate, an in-coupling region and an out-coupling region, the in-coupling region is provided with a first grating for The incident light is coupled into the optical waveguide substrate, the coupling-out area is provided with a second grating for two-dimensional expansion of the light from the optical waveguide substrate and then coupled out, the first grating has a coupled-in grating vector , the second grating has a first out-coupling grating vector and a second out-coupling grating vector crossing each other, and the respective grating element arrays of the first grating and the second grating are substantially parallel and periodic in one dimension Likewise, the first out-coupling grating vector and the second out-coupling grating vector have substantially equal magnitudes and are symmetrical with respect to the in-coupling grating vector to form an isosceles triangle together with the in-coupling grating vector
  • P0 is the period of the first grating element array in the first dimension
  • Px and Py are the periods of the second grating element array in the first dimension and the second dimension, respectively
  • s is the The offset in the first dimension direction between two adjacent rows in the second grating unit array
  • k is a coefficient ranging from 0.45 to 0.55.
  • the size range of the period P0 of the first grating unit array is 250nm-500nm, and the period Py and the period Px of the second grating unit array The ratio is 0.7-1.2.
  • the second grating further has a derived grating vector, the magnitude of the derived grating vector being between the magnitude of the coupled-in grating vector The ratio is 0.45-0.55.
  • the second grating is a two-dimensional surface relief grating
  • the second grating unit array has a second-order or higher-order column array structure
  • the The cross-sectional shape of the cylinder includes circle, ellipse, polygon and any combination thereof.
  • the two-dimensional surface relief grating has a third-order column array structure, which includes:
  • first pillars arranged to form the second array of grating elements, each of which protrudes outwardly from an outer surface of the outcoupling region and has a first height in a direction perpendicular to the outer surface ;as well as
  • a plurality of second cylinders each of which is disposed on top of a corresponding first cylinder and has a second height in a direction perpendicular to the outer surface, the bottom surfaces of the second cylinders being contained within the In the top surface of the first cylinder, the area of the bottom surface of the second cylinder is smaller than the area of the bottom surface of the first cylinder.
  • the second column is arranged to be offset relative to the first column toward a direction in which the first grating is located.
  • the bottom surface of the second cylinder is tangent to the bottom surface of the first cylinder, and the tangent point is located at the second cylinder in the offset direction.
  • the bottom surface of the second cylinder is reduced proportionally according to the bottom surface of the first cylinder at a preset reduction ratio.
  • the reduction ratio is in the range of 0.45-0.65.
  • the second column In the optical waveguide device for AR equipment according to the present invention, optionally, in a two-dimensional plane formed by the first dimension direction and the second dimension direction of the second grating unit array, the second column The projection of the body in the two-dimensional plane is smaller than the projection of the corresponding first cylinder in the two-dimensional plane at least in three directions.
  • the range of the first height is 30nm-65nm, and the second height and the first height have substantially the same high.
  • the first grating includes a blazed grating, a tilted grating and a binary grating.
  • the thickness of the optical waveguide substrate is 0.3 mm-2.5 mm, and the refractive index is 1.4-2.2.
  • an AR device is also provided, and the AR device includes:
  • An image projection device which is arranged on the light incident side of the optical waveguide device, is used for sending out image light rays so as to be incident on the coupling-in area of the optical waveguide device.
  • a manufacturing method of an optical waveguide device for AR equipment comprising the steps of:
  • a coupling-out region is provided with a second grating, the second grating has a first coupling-out grating vector and a second coupling-out grating vector, and the light from the optical waveguide substrate is two-dimensionally expanded and then coupled out, wherein the The grating element array of the second grating is substantially parallel and the same period in one dimension as the grating element array of the first grating, and the first out-coupling grating vector and the second out-coupling grating vector have equal magnitudes value and both form an isosceles triangle with the in-coupling grating vector, the magnitude of the composite vector of the in-coupling grating, the first out-coupling grating vector and the second out-coupling grating vector being substantially equal to zero.
  • the first grating is configured to have a first grating that is periodically arranged in a first dimensional direction perpendicular to the grating groove line direction thereof.
  • a first grating element array and the second grating is configured to have a second grating element array periodically arranged in the first dimensional direction and a second dimensional direction perpendicular thereto, the first grating element
  • the periods of the array and the second grating element array conform to the following relation:
  • P0 is the period of the first grating element array in the first dimension
  • Px and Py are the periods of the second grating element array in the first dimension and the second dimension, respectively
  • s is the The offset in the first dimension direction between two adjacent rows in the second grating unit array
  • k is a coefficient ranging from 0.45 to 0.55.
  • the period P0 of the first grating unit array ranges in size from 250 nm to 500 nm, and the period Py of the second grating unit array The ratio to the period Px is 0.7-1.2.
  • the second grating further has a derived grating vector, and the magnitude of the derived grating vector is the same as the magnitude of the coupled-in grating vector.
  • the ratio between the values is 0.45-0.55.
  • the second grating is configured as a two-dimensional surface relief grating
  • the second grating element array of the second grating includes a second-order grating Or a higher-order column array structure
  • the cross-sectional shape of the column includes a circle, an ellipse, a polygon, and any combination thereof.
  • the two-dimensional surface relief grating has a third-order column array structure, which includes:
  • first pillars arranged to form the second array of grating elements, each of which protrudes outwardly from an outer surface of the outcoupling region and has a first height in a direction perpendicular to the outer surface ;as well as
  • a plurality of second cylinders each of which is disposed on top of a corresponding first cylinder and has a second height in a direction perpendicular to the outer surface, the bottom surfaces of the second cylinders being contained within the In the top surface of the first cylinder, the area of the bottom surface of the second cylinder is smaller than the area of the bottom surface of the first cylinder.
  • an optical waveguide device for AR equipment which includes an optical waveguide substrate, an in-coupling region and an out-coupling region, wherein the coupling-in region is provided with a first grating for The incident light is coupled into the optical waveguide substrate, the coupling-out area is provided with a second grating for two-dimensional expansion of the light from the optical waveguide substrate and then coupled out, the first grating has a coupled-in grating vector , the second grating has a first out-coupling grating vector and a second out-coupling grating vector crossing each other, wherein the respective grating element arrays of the first grating and the second grating are substantially parallel in one dimension and the period is the same, the first out-coupling grating vector and the second out-coupling grating vector are symmetrical with respect to the coupling-in grating vector and form an isosceles triangle together with the coupling-in grating vector,
  • the second grating is a two-dimensional surface relief grating
  • the two-dimensional surface relief grating has a third-order column array structure, which includes:
  • first pillars arranged to form the second array of grating elements, each of which protrudes outwardly from an outer surface of the outcoupling region and has a first height in a direction perpendicular to the outer surface ;as well as
  • a plurality of second cylinders each of which is disposed on top of a corresponding first cylinder and has a second height in a direction perpendicular to the outer surface, the bottom surfaces of the second cylinders being contained within the In the top surface of the first cylinder, the area of the bottom surface of the second cylinder is smaller than the area of the bottom surface of the first cylinder.
  • the first grating has a first grating element array periodically arranged in a first dimensional direction perpendicular to the grating groove line direction thereof
  • the second grating has a second grating element array periodically arranged in the first dimensional direction and a second dimensional direction perpendicular thereto, and the first grating element array and the second grating element array are The period conforms to the following relationship:
  • P0 is the period of the first grating element array in the first dimension direction
  • Px and Py are the period of the second grating element array in the first dimension direction and the second dimension direction, respectively.
  • period, s is the offset between two adjacent rows in the second grating unit array in the first dimension direction
  • k is a coefficient ranging from 0.45 to 0.55.
  • the size range of the period P0 of the first grating unit array is 250nm-500nm, and the period Py and the period Px of the second grating unit array The ratio is 0.7-1.2.
  • the second grating further has a derived grating vector, the magnitude of the derived grating vector being between the magnitude of the coupled-in grating vector The ratio is 0.45-0.55.
  • the cross-sectional shape of the cylinder of the third-order cylinder array structure includes a circle, an ellipse, a polygon, and any combination thereof.
  • the surfaces of the third-order columns of the third-order column array structure have gradients with heights decreasing in at least three directions, wherein the first The direction is the transmission direction of the light coupled into the second grating, the second direction is the transmission direction of the turning light on the left side of the second grating, and the third direction is the transmission direction of the turning light on the right side of the second grating.
  • the second column is arranged to be offset relative to the first column toward a direction in which the first grating is located.
  • the bottom surface of the second cylinder is tangent to the bottom surface of the first cylinder, and the tangent point is located at the second cylinder in the offset direction.
  • the bottom surface of the second cylinder is reduced proportionally according to the bottom surface of the first cylinder at a preset reduction ratio.
  • the reduction ratio is in the range of 0.45-0.65.
  • the second column In the optical waveguide device for AR equipment according to the present invention, optionally, in a two-dimensional plane formed by the first dimension direction and the second dimension direction of the second grating unit array, the second column The projection of the body in the two-dimensional plane is smaller than the projection of the corresponding first cylinder in the two-dimensional plane at least in three directions.
  • the range of the first height is 30 nm-65 nm, and the second height and the first height have substantially the same height.
  • the second grating element array is arranged to be convex outward or inwardly concave from the outer surface of the coupling-out region, and the first grating element array
  • An array of barrier elements is arranged to project outwardly or inwardly from the outer surface of the coupling region.
  • the first grating includes a blazed grating, a tilted grating and a binary grating.
  • the thickness of the optical waveguide substrate is 0.3 mm-2.5 mm, and the refractive index is 1.4-2.2.
  • an AR device is further provided, wherein the AR device includes:
  • An image projection device which is arranged on the light incident side of the optical waveguide device, is used for sending out image light rays so as to be incident on the coupling-in area of the optical waveguide device.
  • an out-coupling region is provided with a second grating
  • the second grating has a first out-coupling grating vector and a second out-coupling grating vector crossing each other and two-dimensionally expands the light from the optical waveguide substrate and couples it out
  • the grating element array of the second grating and the grating element array of the first grating are substantially parallel in one dimension and have the same period, and the first out-coupling grating vector and the second out-coupling grating vector are relative to each other.
  • the coupled-in grating vector forms symmetry and together with the coupled-in grating vector forms an isosceles triangle
  • the second grating is constructed as a two-dimensional surface relief grating, and the two-dimensional surface relief grating has a third-order column array structure, which includes:
  • first pillars arranged to form the second array of grating elements, each of which protrudes outwardly from an outer surface of the outcoupling region and has a first height in a direction perpendicular to the outer surface ;as well as
  • a plurality of second cylinders each of which is disposed on top of a corresponding first cylinder and has a second height in a direction perpendicular to the outer surface, the bottom surfaces of the second cylinders being contained within the In the top surface of the first cylinder, the area of the bottom surface of the second cylinder is smaller than the area of the bottom surface of the first cylinder.
  • the first grating is configured to have a first grating that is periodically arranged in a first dimensional direction perpendicular to the grating groove line direction thereof.
  • a first grating element array and the second grating is configured to have a second grating element array periodically arranged in the first dimensional direction and a second dimensional direction perpendicular thereto, the first grating element
  • the periods of the array and the second grating element array conform to the following relation:
  • P0 is the period of the first grating element array in the first dimension direction
  • Px and Py are the period of the second grating element array in the first dimension direction and the second dimension direction, respectively.
  • period, s is the offset between two adjacent rows in the second grating unit array in the first dimension direction
  • k is a coefficient ranging from 0.45 to 0.55.
  • the period P0 of the first grating unit array ranges in size from 250 nm to 500 nm, and the period Py of the second grating unit array The ratio to the period Px is 0.7-1.2.
  • the second grating further has a derived grating vector, and the magnitude of the derived grating vector is the same as the magnitude of the coupled-in grating vector.
  • the ratio between the values is 0.45-0.55.
  • the cross-sectional shape of the cylinder of the third-order cylinder array structure includes a circle, an ellipse, a polygon, and any combination thereof.
  • the surface of the third-order pillars of the third-order pillar array structure has a gradient of decreasing height in at least three directions, wherein, The first direction is the transmission direction of the light coupled into the second grating, the second direction is the transmission direction of the refracted light on the left side of the second grating, and the third direction is the transmission direction of the refracted light on the right side of the second grating.
  • the technical solution of the present invention can not only make the optical waveguide device easy to realize two-dimensional pupil dilation, but also not limited to the equilateral triangle grating array arrangement, thereby helping to improve the design freedom of the existing optical waveguide sheet, and promoting the product structure to be more It is compact and lightweight, and can make the viewing angle range larger, and the directions of the out-coupled light and the coupled-in light are basically the same, so that it is easy to realize the projection image display with basically no aberration.
  • the present invention can effectively reduce the light energy loss caused by the diffraction order transmitted to the world side, thereby helping to enhance the diffraction efficiency on the user side and improve the endurance of the AR device.
  • the optical waveguide device and the AR device according to the present invention have a simple and compact structure, are very suitable for mass production, and have good industrial application value.
  • FIG. 1 is a schematic three-dimensional structure diagram of an embodiment of an optical waveguide device according to the present invention.
  • FIG. 2 is a schematic side view of the structure of the embodiment of the optical waveguide device shown in FIG. 1 , in which a micro-projector and a human eye are also schematically shown.
  • FIG. 3 is a schematic structural diagram of a common column array in the prior art.
  • FIG. 4 is a schematic structural diagram of an example of a columnar grating unit array of the second grating in the embodiment of the optical waveguide device shown in FIG. 1 .
  • FIG. 5 shows the in-coupling grating vector G0, the out-coupling grating vector G1 and G2 corresponding to the coupling-in grating element H0, the coupling-out grating elements H1 and H2, respectively, in the embodiment of the optical waveguide device shown in FIG. 1, these The raster vectors G0, G1 and G2 now form an isosceles triangle.
  • FIG. 6 shows the coupling-in grating vector G0 and the coupling-out derivative grating vector G3 corresponding to the coupling-in grating element H0 and the coupling-out grating element H3 respectively in the embodiment of the optical waveguide device.
  • FIG. 7 is a schematic diagram of an optical transmission path of light in the embodiment of the optical waveguide device.
  • FIG. 8 is a front view of the optical transmission path shown in FIG. 7 in the xoy plane.
  • FIG. 9 shows the first horizontal field of view Fx1 provided by the standard grating element H1 from the optical signal transmitted by the first grating.
  • Figure 10 shows the second horizontal field of view Fx2 provided by the standard grating element H2 from the optical signal transmitted by the first grating.
  • FIG. 11 shows corresponding graphs of the range of fields of view supported by the second grating in this embodiment of the optical waveguide device under three different two-dimensional period ratios.
  • Figure 12 shows a K vector diagram of an embodiment of an optical waveguide device with a large field of view.
  • Figure 13 shows three different examples of second-order cell arrays.
  • Figure 14 shows the situation in which an outward transmissive diffraction order T1 and an inward reflective diffraction order R1 are simultaneously generated each time the image light is coupled out by the second grating in the embodiment of the optical waveguide device.
  • FIG. 15 shows that when the second grating in the embodiment of the optical waveguide device is selected as a second-order columnar unit array, the bottom surface of the columnar body presents a convex hexagon that is symmetrical about the y-axis.
  • Figure 16 shows the respective transmission diffraction orders T1 and reflection diffraction orders R1 of the s-polarized light and p-polarized light transmitted in the second grating using the second-order hexagonal element array, which are simulated based on the Fourier mode method.
  • Figure 17 shows the corresponding structures of examples of third-order grating elements with different base cylinders, respectively, for the second grating.
  • FIG. 18 is a different view of the third-order hexagonal cylinder cell structure of example (c) shown in FIG. 17 .
  • FIG. 19 shows the situation when the third-order hexagonal column structure shown in FIG. 18 is arranged into a two-dimensional grating element array coupled out of the grating.
  • Fig. 20 shows the out-coupling diffraction efficiency of the respective transmission diffraction orders T1 and reflection diffraction orders R1 of the s-polarized light and p-polarized light transmitted in the out-coupling grating of the two-dimensional grating element array shown in Fig. 18 as a function of the incident angle ⁇ curve.
  • FIG. 33 is a flowchart of an embodiment of a method of manufacturing an optical waveguide device according to the present invention.
  • optical waveguide device for AR equipment and its manufacturing method according to the present invention and the steps, structures, features and advantages of the AR equipment will be described below by way of example, but all descriptions should not be used without any limitation of the present invention.
  • technical terms “first” and “second” are only used for the purpose of distinguishing expressions and are not intended to indicate their order and relative importance, etc.
  • the technical term “substantially” is intended to include a specific amount of The insubstantial error associated with the measurement, which may include, for example, a range of ⁇ 8%, ⁇ 5%, or ⁇ 2% of a given value, technical terms “upper”, “lower”, “right”, “left”, “horizontal” ”, “vertical” and derivatives thereof shall be associated with the orientations in the various figures, and it is to be understood that the invention may take various alternative orientations.
  • the optical waveguide device is constructed substantially in the form of a sheet and includes an optical waveguide substrate 1 , an in-coupling region 2 and an out-coupling region 3 .
  • the optical waveguide substrate 1 is transparent to visible light, and it may generally have two opposing optical planes.
  • the optical waveguide substrate 1 will carry out total reflection and transmission of the image light entering the inside thereof, and its thickness can be optionally set to 0.3mm-2.5mm, and the refractive index is 1.4-2.2.
  • a light-weight, high-refractive-index optical waveguide substrate is preferably used.
  • a coupling-in region 2 can be arranged at one end of the optical waveguide substrate 1, and a first grating (or called coupling-in grating) can be set in the coupling-in region 2, so as to be used to convert the received Incident light rays (eg, image light rays from the micro projector 4 shown in FIG. 2 ) are coupled into the optical waveguide substrate 1 , thereby realizing total reflection transmission in the optical waveguide substrate 1 .
  • the first grating can be a one-dimensional surface relief grating, and the grating grooves can be arranged parallel to the x-axis, as shown in FIG. 1 , for example.
  • the out-coupling region 3 it can be arranged at the other end of the optical waveguide substrate 1 , and a second grating (or referred to as an out-coupling grating) can be arranged in the out-coupling region 3 , so as to be used to convert the optical fiber via the in-coupling region 2
  • the light entering the optical waveguide substrate 1 is expanded two-dimensionally, and is coupled out of the optical waveguide substrate 1 along the z-axis direction, and then diffracted into the human eye 5 .
  • a two-dimensional surface relief grating may be used as the second grating, so as to form a cooperation with the above-mentioned first grating, which will be described in detail later.
  • FIG. 3 A common column array structure in the prior art is schematically illustrated in FIG. 3 , which has a horizontal period Px in the x-axis direction, a vertical period Py in the y-axis direction, and a row offset s.
  • the above grating period P0 can optionally be set to be sufficiently small, so that the diffraction order corresponding to the incident light can better satisfy the condition of total reflection and be captured by the optical waveguide substrate 1.
  • the period P0 can be The value range is set to 250nm-500nm.
  • FIGS. 5 and 6 The corresponding grating vectors that can be set for the respective periodic structures of the first grating and the second grating are shown in FIGS. 5 and 6 , respectively, wherein in FIG. 5 the coupling of the grating elements on the optical waveguide is shown H0, the coupling-in grating vector G0, the coupling-out standard grating vector G1 and G2 corresponding to the coupling-out grating elements H1 and H2, respectively, in FIG. Element H3 corresponds to the coupled-in grating vector G0 and the coupled-out derived grating vector G3 respectively.
  • a micro-projector 3 is used to project image rays to the optical waveguide device.
  • the grating diffraction and turning effect of the image rays each time can be represented by the vector superposition of the grating vector and the light wave vector.
  • the optical waveguide device needs to meet the achromatic imaging conditions when completing the image transmission, that is, after the image light incident at different wavelengths and angles is finally coupled out through its diffusion and transmission, the direction of the outgoing light should be consistent with the incoming light, which requires the outgoing light wave.
  • the vector can be consistent with the wave vector of the incident light.
  • the diffractive turning effects of multiple gratings need to cancel each other out in the working plane of the optical waveguide, which manifests as the sum of the superposition of these grating vectors equal to zero, or substantially zero, which can be, for example, below a certain level depending on the application requirements.
  • the set threshold is used as the criterion.
  • the magnitudes of the coupled out standard grating vectors G1 and G2 can be calculated according to the following relationship:
  • the superposition vector coupled out of both standard grating vectors G1 and G2 can be expressed as:
  • the above grating vectors G0, G1, G2 can be encircled into an isosceles triangle instead of being limited to an equilateral triangle, and no additional synthetic vector is generated, and achromatic imaging is also achieved. conditions are met.
  • it can also be considered to set the line offset s to be k times the period Px (k ⁇ 0.5 but within the range of 0.45-0.55), although the achromatic imaging at this time is not optimal , but it can also obtain better results, so that it can fully and flexibly meet various application needs.
  • the present invention enables out-coupling of light with substantially no angular or chromatic shift by employing such grating arrangements and combinations as suggested above. Since the two out-coupled standard grating vectors G1 and G2 of the second grating cross each other and form a symmetrical arrangement with respect to the coupled-in grating vector G0 of the first grating, they can together form an isosceles triangle, which is not limited to equal The arrangement of the grating array with a side triangle is very advantageous for improving the design freedom and compactness of the optical waveguide device.
  • the second grating is symmetrical to the two-dimensional expansion of the incident light. Its two out-coupled standard vectors can output the optical waveguide device after diffracting the incident light twice, and its output direction is consistent with the input direction. The effect is independent of wavelength, so color display can be easily realized.
  • the diffraction characteristics possessed by the two-dimensional relief grating cannot only be regarded as the superposition of the coupling-out grating elements H1 and H2.
  • the derivative gratings H3 periodically arranged along the y-axis direction will also couple the light beam out of the optical waveguide device.
  • this part of the outgoing beam may also be required to satisfy the achromatic condition.
  • the raster vector G3 of the derived grating H3 can be expressed as:
  • the best effect is achieved when the size of the derived grating vector G3 is half of that of the coupled grating vector G0.
  • a better effect can be achieved when the size ratio of the two is set in the range of 0.45-0.55.
  • the second-order diffraction grating vector corresponding to the derivative grating H3 is twice the derivative grating vector G3
  • the sum of its second-order diffraction grating vector and the coupled-in grating vector is equal to zero, as shown in Figure 6, the grating vector passes through two
  • the superposition of the derived grating vectors G3 returns to the origin, thus satisfying the achromatic imaging condition.
  • FIG. 7 is a schematic diagram of an optical transmission path of light in the embodiment of the optical waveguide device
  • FIG. 8 is a front view of the optical transmission path shown in FIG. 7 in the xoy plane.
  • Figures 7 and 8 when the image light from the first grating is incident on the second grating, a plurality of different diffractions will be simultaneously generated by the action of different grating elements contained in the latter, wherein the light is The second grating is received at point A and will experience four diffractions simultaneously.
  • the coupled light O After the coupled light O is received at point A, it will firstly be directly coupled out of the optical waveguide device by the derived grating element H3 at -2 level a1, and transmitted along the z-axis direction toward the observer's eye.
  • the light received at point A is then diffracted to zero order a2, which is a continuation of the direction of propagation of the incident light.
  • the zeroth-order light a2 is allocated most of the light energy, it can continue to point B and subsequent points of action on the same path, and at these points further diffraction effects similar to point A occur.
  • the light received at point A also interacts with the standard grating element H1 to produce first-order laterally diffracted light a3, which is diffracted in a direction at an angle ⁇ with the x-axis (which is consistent with the angle ⁇ in Figure 4) , and continues to interact with the standard grating element H2 in the two-dimensional grating at point C, resulting in the outcoupling diffraction order c1. Since c1 undergoes the diffraction effect of the above three grating elements H0, H1, and H2 in turn, the corresponding superposed grating vectors G0, G1, and G2 have a counteracting effect.
  • the angular characteristics and chromaticity characteristics of the diffraction order c1 will be related to the coupling effect.
  • the incident light O remains the same.
  • the light incident at point C will also interact with the standard grating element H1 to make it conjugate with the action of the standard grating element H1 at point A, corresponding to the superposition of two standard grating vectors G1 in opposite directions.
  • the diffraction order c3 towards point F is obtained, and the transmission direction of c3 is consistent with the coupled light O at point A.
  • Light c3 will further produce diffraction similar to point A at point F and subsequent points of action along the same path along the -y axis.
  • zero-order light c2 incident at point C will continue to produce further diffraction effects similar to point C at point E and subsequent points of action on the same path along the direction of ⁇ with the x-axis.
  • the light received at point A also interacts with standard grating element H2 to produce first-order laterally diffracted light a4 and travels to point D. Since both the standard grating elements H2 and H1 have symmetry with respect to the y-axis, the subsequent diffracted transmission path of a4 is also symmetric to a3. This path creates diffusion and outcoupling towards the left side of the optical waveguide. After a series of diffraction and transmission, light can finally be coupled out from the left and right sides of the coupling-out region of the optical waveguide device, so that the observer's eyes can observe a complete and continuous image at any position in the above-mentioned region.
  • the optical transmission paths shown in FIGS. 7 and 8 are light rays coupled in along the z-axis direction
  • the optical transmission paths shown in FIGS. 7 and 8 are light rays coupled in along the z-axis direction
  • the side diffracted ray a3 or a4 will disappear due to the inability to satisfy the effective total reflection transmission, and the remaining one side diffracted ray corresponds to the standard
  • the grating element retains the ability to effectively diffract and transmit the coupled light rays at this part of the angle.
  • Fig. 9 and Fig. 10 show the case where the standard grating elements H1 and H2 respectively provide the first horizontal field of view Fx1 and the second horizontal field of view Fx2 from the optical signal transmitted by the first grating .
  • the standard grating element H1 can provide a first horizontal field angle Fx1 of the optical signal transmitted from the first grating, and the optical signal received at the first grating will be transmitted to the second grating as diffracted light a3
  • the grating contains another standard grating element H2, which acts as an output diffractive optical element, coupling light from the optical waveguide to the observer. As shown in Fig.
  • the standard grating element H2 can provide a second horizontal field of view Fx2 from the optical signal transmitted by the first grating, and the optical signal received at the first grating will be transmitted to the first grating as diffracted light a4.
  • the second grating contains another standard grating element H1, which acts as an output diffractive optical element to couple light from the optical waveguide device to the observer.
  • first horizontal angle of view Fx1 and the second horizontal angle of view Fx2 partially overlap, they contain another angle with respect to each other that is not contained in each other.
  • the total field angle Fx supported by the second grating will also be larger.
  • Fy is the field of view of the transmitted image rays along the y-axis, which will be limited by the refractive index of the waveguide material. The present invention has found that if the vertical period Py and the horizontal period Px of the second grating are both set to different ratios, this will have a significant effect on the supported horizontal total field angle Fx.
  • the optical waveguide substrate 1 can be set as an optical flat glass with a refractive index of 1.7 and a thickness of 1 mm, the first grating period P0 is 340 nm, the horizontal period Px of the second grating is 392.6 nm, and the vertical
  • the area enclosed by the dotted curve shown in the figure and the y-axis defines the half field of view of the optical waveguide device.
  • the optical waveguide substrate 1 can be set as an optical flat glass with a refractive index of 1.7 and a thickness of 1 mm, the first grating period P0 is 340 nm, the horizontal period Px of the second grating is 360 nm, and the vertical period is 360 nm.
  • the area surrounded by the y-axis of the star-point curve shown in the figure defines the half field of view of the optical waveguide device.
  • the optical waveguide substrate 1 can be set as an optical flat glass with a refractive index of 1.7 and a thickness of 1 mm, the first grating period P0 is 340 nm, the horizontal period Px of the second grating is 340 nm, and the vertical period is 340 nm.
  • the area enclosed by the y-axis of the quadrangular-point curve shown in the figure defines the half-field of view of the optical waveguide device.
  • the horizontal field of view when the two-dimensional period ratio w is equal to 1 is increased by about 65% compared to the horizontal field of view when w is equal to 0.866. Therefore, it is believed that with the further increase of the two-dimensional period ratio w, the field of view in the horizontal direction can be further expanded.
  • the two-dimensional period is relatively larger than w, the adjacent exit pupils of the optical waveguide device will have an excessive distance, which is not conducive to the continuous distribution of the light energy at the exit pupil, and is not conducive to the coupling of the optical waveguide device to the image. Uniformity; in contrast, if the 2D period is relatively small compared to w, it may be difficult to support a large field of view. Therefore, according to the research results of the present inventors, it is considered advantageous to optionally set the two-dimensional period ratio w in the range of 0.7-1.2.
  • FIG. 12 a K vector diagram of an example of an optical waveguide device with a large field of view is shown.
  • circle O1 represents the lower limit of the transmission angle of the optical waveguide device limited by the minimum total reflection angle
  • circle O2 represents the upper limit of the transmission angle determined by the transmission mode in the optical waveguide device
  • the annular shaded area represents the effective transmission angle of the field of view.
  • the angular space area, F1 represents the projected field of view corresponding to the collimated light projected by the optical projector refracted into the transmission field of view corresponding to the optical waveguide device
  • P1 represents the transmission field of view generated by the coupled grating element H0 after diffraction.
  • the field F1 becomes the transmission field of view F4
  • P2 means that a part of the transmission field of view F4 is transformed into the transmission field of view F3 after diffraction by the standard grating element H1
  • P4 means that the transmission field of view F3 is generated by the diffraction of the standard grating element H2.
  • Coupling out of the optical waveguide device and leaving the effective transmission area P3 means that a part of the transmission field of view F4 is transformed into the transmission field of view F2 after the diffraction effect by the standard grating element H2, and P5 means that the standard grating element H1 produces the diffraction effect to transmit the field of view.
  • F2 is coupled out of the optical waveguide device away from the effective transmission area. After leaving the optical waveguide device, the partial fields of view located on both sides will be combined into a complete field of view F1 again, and then received by the observer's eyes.
  • second order element arrays that can be used for the second grating are shown in FIG. 13 by way of example only.
  • the second-order rectangular element array shown in example (a) in the figure, the concave polygon element array shown in example (b), and the second-order convex polygon (containing an interior angle greater than 180°) shown in example (c) can be used ) cell array
  • the present invention also allows the use of other arbitrary shape cell arrays such as elliptical cell arrays, or even cell arrays of some combined graphics.
  • these cell array structures may be in the shape of cylinders, which have a broad meaning herein, for example, to cover a multitude of relatively simple or rather complex configurations such as pyramids, pyramids, hemispheres, oblique prisms, etc., Using these different structural shapes can only change the energy distribution of the different diffraction orders of the two-dimensional grating without changing the optical transmission path.
  • these unit array structures can protrude from the surface of the base material, or can be recessed on the surface of the base material, and there may be a coating layer or an air environment above them, but the refractive index is formed on both sides of the unit array structure. The difference is a necessary condition for diffraction to occur. Based on the above teachings of the present invention, those skilled in the art will understand that there are actually a large number of suitable structural shapes for the second grating in an optical waveguide device.
  • the second grating element array can be selected, for example, as shown in FIG. 15 , the bottom surface of the column is a convex hexagon that is symmetrical about the y-axis.
  • 460 nm blue light can be used as the coupled-in light source, and correspondingly, an optical waveguide substrate with a refractive index of 1.7 is used.
  • the incident ray travels along the AC (or AD) direction in the figure in the xoy plane, and the incident ray can form an incident angle ⁇ with the z-axis.
  • the second grating in the optical waveguide device can be optionally arranged as a high-order columnar array structure of, for example, three or more orders.
  • the research and analysis according to the present invention shows that the use of such a high-order columnar array structure can effectively reduce the light energy loss caused by the diffraction order transmitted to the world side.
  • the stepped columnar array structure includes a plurality of first columns 11 and a plurality of second columns 12 protruding from the surface of the waveguide, the columns are arranged in a two-dimensional periodic array, and each of the first columns 11 Having a first height d1 in the direction perpendicular to the waveguide surface, each of the second pillars 12 protrudes from the upper surface of the first pillar 11 and has a second height d2, for the second height in the solution according to the invention
  • the relationship between d2 and the first height d1 is not particularly limited, for example, it is generally considered to set them to have substantially equivalent heights, that is, those skilled in the art can understand that as long as the two are in the order of height dimensions The height is roughly the same, and the height difference is not too large.
  • the bottom surface of the second cylinder 12 is also generally smaller than the bottom surface of the first cylinder 11 , so its lower surface will be contained within the upper surface of the first cylinder 11 .
  • the second cylinder 12 can be offset relative to the first cylinder 11 , and the offset direction is the direction in which the coupled-in grating is located.
  • the bottom surface of the second cylinder 12 can be configured so that the bottom surface of the second cylinder 12 is proportionally reduced in proportion to the bottom surface of the first cylinder 11 , and the bottom surface of the second cylinder 12 can be tangent to the bottom surface of the first cylinder 11 .
  • the tangent point is in the above-mentioned offset direction.
  • FIG. 17 several third-order grating elements with different bottom surface cylinders that can be used for the second grating are respectively shown.
  • the surfaces of these third-order cylinder examples (a), (b) and (c) may have gradients that are highly descending in at least three directions, the first of which is where the light is coupled into the second grating
  • the transmission direction (refer to the AB direction in Figure 15)
  • the second direction is the transmission direction of the turning light on the left side of the second grating (refer to the AD direction in Figure 15)
  • the third direction is the right turning direction of the second grating
  • the direction of light transmission see AC direction in Figure 15).
  • FIG. 18 A different view of the third order cylinder example (c) shown in FIG. 17 is further provided in FIG. 18 .
  • FIG. 19 schematically illustrates the arrangement of the third-order cylindrical structure shown in FIG. 18 into a two-dimensional array of grating elements out-coupling gratings.
  • the cell arrays are aligned for comparison purposes.
  • Figure 20 shows the out-coupling diffraction efficiency curves of the respective transmission diffraction orders T1 and reflection diffraction orders R1 of the s-polarized light and p-polarized light transmitted in the above-mentioned third-order grating element array as a function of the incident angle ⁇ ,
  • the incident light uses 460 nm blue light, which propagates along the AC (or AD) direction as shown in FIG. 15 in the xoy plane.
  • the diffraction efficiency of the reflection level R1 on the user side can reach 2-3 times that of the transmission level T1 on the world side. It can be seen that, by using the above solution according to the present invention, the reflection level R1 can be greatly enhanced, thereby improving the diffraction efficiency of the user terminal, and the transmission level T1 can be effectively suppressed.
  • Fig. 21 to Fig. 32 respectively show the case of performing optimization simulation of the diffraction efficiency of the second grating example using the above-mentioned third-order grating element array.
  • the diffraction efficiency of the reflection diffraction order R1 varies as a function of the reduction ratio v and the first height d1 of the first cylinder.
  • the diffraction efficiency on the user side is high, and the diffraction efficiency on the world side is low.
  • the total height d of different third-order cylinders has no significant influence on the region where the ellipse is located within a certain range, and the reduction rate v in this region is about 0.45-0.65.
  • the first height d1 is approximately in the range of 30nm-65nm.
  • an AR device is also provided, on which one or more of the above-discussed optical waveguide devices according to the present invention can be configured, and by arranging the projection device on the optical waveguide device The light incident side, so as to send the image light to the coupling region of the optical waveguide device. Due to the above-mentioned corresponding arrangement and combination of the first grating and the second grating, the AR device can provide the coupling output of light without substantially angular or chromatic shift, which is not only easy to realize two-dimensional Dilated pupils, higher design freedom, wider field of view, and can effectively reduce transmitted diffracted light to improve energy efficiency and enhance the endurance and product competitiveness of AR devices.
  • a manufacturing method of an optical waveguide device for AR equipment is also provided, which is easy to mass-produce and process, and has high production efficiency, so it has strong industrial application value.
  • FIG. 33 in this embodiment, the general steps for fabricating the optical waveguide device of the present invention are given.
  • an optical waveguide substrate can be provided;
  • an in-coupling region with a first grating may be provided, for example, the coupling-in region may be provided at one end of the optical waveguide substrate, the first grating has an in-coupling grating vector and enables incident light to be coupled into the optical waveguide substrate Inside;
  • an out-coupling region with a second grating may be provided, for example, the out-coupling region may be provided at the other end of the optical waveguide substrate, and the second grating has a first coupling-out grating vector and a second coupling-out grating intersecting each other.
  • the first out-coupling grating vector and the second out-coupling grating vector have substantially equal magnitudes, and they are arranged symmetrically with respect to the coupling-in grating vector, so that the first out-coupling grating vector, the second out-coupling grating vector and the The three coupled into the grating vector together form an isosceles triangle.
  • optical waveguide device for AR equipment and the manufacturing method thereof and the AR equipment according to the present invention are described in detail above only by way of example. Limitation, without departing from the spirit and scope of the present invention, those skilled in the art can also make various modifications and improvements.
  • the optical waveguide device in the AR device generally adopts an overall sheet-like structure
  • the optical waveguide device in the present invention can adopt any suitable structural form, for example, it can be allowed to locally form a shape such as a bump in some cases. Therefore, all equivalent technical solutions should belong to the scope of the present invention and be defined by the various claims of the present invention.

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Abstract

用于AR设备的光波导装置及其制造方法和AR设备。光波导装置包括光波导基底（1）、耦入区（2）和耦出区（3），所述耦入区（2）设有第一光栅用以将入射光线耦入所述光波导基底（1）内，所述耦出区（3）设有第二光栅用以将来自所述光波导基底（1）的光线二维扩展后耦出，第一光栅具有耦入光栅矢量，第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量，第一光栅和第二光栅各自的光栅单元阵列在一个维度方向上基本上平行且周期相同，第一耦出光栅矢量和第二耦出光栅矢量具有基本上相等的量值且相对于耦入光栅矢量形成对称，从而由它们与耦入光栅矢量一起组成等腰三角形。

Description

用于AR设备的光波导装置及其制造方法和AR设备 技术领域
本发明涉及光学成像技术领域，尤其涉及用于AR设备的光波导装置及其制造方法和AR设备。
背景技术
光波导片是新一代增强现实技术(Augmented Reality，AR)中的关键核心部件，它将全反射波导原理和衍射元件相结合，用来在成像系统中复制扩展出射光瞳，由于具有大光瞳、小体积、重量轻等优点，因此已经成为AR技术发展的必然趋势。
典型的光波导技术是将微型显示器出射的图像光源通过投影镜头投射进入光波导片的入射光栅区域，其被光波导片捕获并全反射传输至第二个光栅区域后再被衍射转折90°，同时透射的光继续沿原方向全反射前进，每次被转折光栅衍射进而实现在第一方向上的一维扩展。已转折90°的光将朝向第三光栅全反射，第三光栅的栅线与入射光正交，光可以在与第三光栅交互的每个点处被衍射耦出或者透射，透射光将通过全反射继续沿着该方向传输，第三光栅可提供在第二方向上的一维扩展，因此衍射耦出至观看者的图像光源可实现二维扩展。此类光波导片所使用的三个光栅皆为一维表面浮雕光栅。
当两个耦出光栅被重叠设置时，两个一维表面浮雕光栅可使用一个二维表面浮雕光栅来替代，用来直接实现光线的二维扩展和耦出。现有技术方案中二维表面浮雕光栅的柱状结构局限于等边三角形阵列的排布方式，这样的设置限制了光栅设计的自由度，并且水平视场角较小。
另外，当每次图像光线被二维光栅耦出时，会同时产生向外的透射衍射级和向内的反射衍射级。一般来说，需要更多的图像光指向用户侧而不是世界侧，因为指向世界侧的图像光不仅本质上是浪费的，而且还会导致周围人群观看到使用者的内容。
本节所描述内容是为方便理解本申请之用，因此不应假定仅由于将其包含在本节中而认为已经属于现有技术。
发明内容
有鉴于此，本发明提供了一种用于AR设备的光波导装置及其制造方法和AR设备，从而能够解决或者至少缓解了以上问题以及其他方面的问题中的一个或多个。
首先，根据本发明的第一方面，它提供了一种用于AR设备的光波导装置，其包括光波导基底、耦入区和耦出区，所述耦入区设有第一光栅用以将入射光线耦入所述光波导基底内，所述耦出区设有第二光栅用以将来自所述光波导基底的光线二维扩展后耦出，所述第一光栅具有耦入光栅矢量，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量，所述第一光栅和所述第二光栅各自的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量具有基本上相等的量值并且相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光栅具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，所述第二光栅具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
P0＝Py，并且s＝k*Px
其中，P0是所述第一光栅单元阵列在第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在第一维度方向和第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二光栅是二维表面浮雕光栅，所述第二光栅单元阵列具有二阶或者更高阶柱体阵列结构，所述柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
在根据本发明的用于AR设备的光波导装置中，可选地，所述二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体设置成相对于所述第一柱体朝向所述第一光栅所在的方向偏置。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体的底面关于所述第一柱体的底面相切，并且相切点位于所述第二柱体的偏置方向上。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体的底面是按照所述第一柱体的底面以预设的缩小率进行等比例缩小。
在根据本发明的用于AR设备的光波导装置中，可选地，所述缩小率的范围是0.45-0.65。
在根据本发明的用于AR设备的光波导装置中，可选地，在所述第二光栅单元阵列的第一维度方向和第二维度方向上组成的二维平面内，所述第二柱体在该二维平面内的投影至少在三个方向小于与其相对应的第一柱体在该二维平面内的投影。
在根据本发明的用于AR设备的光波导装置中，可选地，其中，所述 第一高度的范围为30nm-65nm，并且所述第二高度与所述第一高度具有基本上相当的高度。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二光栅单元阵列设置成从所述耦出区的外表面向外凸出或者向内凹进，并且所述第一光栅单元阵列设置成从所述耦入区的外表面向外凸出或者向内凹进。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光栅包括闪耀光栅、倾斜光栅和二元光栅。
在根据本发明的用于AR设备的光波导装置中，可选地，所述光波导基底的厚度为0.3mm-2.5mm，折射率为1.4-2.2。
此外，根据本发明的第二方面，还提供了一种AR设备，所述AR设备包括：
一个或多个如以上任一项所述的用于AR设备的光波导装置；以及
投像装置，其布置在所述光波导装置的入光侧用于发送出图像光线，使其入射至所述光波导装置的耦入区。
另外，根据本发明的第三方面，进一步提供了一种用于AR设备的光波导装置的制造方法，所述制造方法包括步骤：
提供光波导基底；
设置具有第一光栅的耦入区，所述第一光栅具有耦入光栅矢量并使得入射光线耦入所述光波导基底内；以及
设置具有第二光栅的耦出区，所述第二光栅具有第一耦出光栅矢量和第二耦出光栅矢量并将来自所述光波导基底的光线进行二维扩展后耦出，其中所述第二光栅的光栅单元阵列与所述第一光栅的光栅单元阵列在一个维度方向上基本上平行且周期相同，并且所述第一耦出光栅矢量和所述第二耦出光栅矢量具有相等量值并且二者与所述耦入光栅矢量一起形成等腰三角形，所述耦入光栅、所述第一耦出光栅矢量和所述第二耦出光栅矢量的合成矢量的量值基本上等于零。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，将所述第一光栅构造成具有在与其光栅槽线方向相垂直的第一维度方向 上周期性排布的第一光栅单元阵列，并且将所述第二光栅构造成具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
P0＝Py，并且s＝k*Px
其中，P0是所述第一光栅单元阵列在第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在第一维度方向和第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，将所述第二光栅构造成二维表面浮雕光栅，所述第二光栅的第二光栅单元阵列包括二阶或者更高阶柱体阵列结构，所述柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
另外，根据本发明的第四方面，进一步提供了一种用于AR设备的光波导装置，其包括光波导基底、耦入区和耦出区，所述耦入区设有第一光栅用以将入射光线耦入所述光波导基底内，所述耦出区设有第二光栅用以将来自所述光波导基底的光线二维扩展后耦出，所述第一光栅具有耦入光栅矢量，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量，其中，所述第一光栅和所述第二光栅各自的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形，
其中，所述第二光栅是二维表面浮雕光栅，该二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光栅具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，所述第二光栅具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
P0＝Py，并且s＝k*Px
其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光 栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
在根据本发明的用于AR设备的光波导装置中，可选地，所述三阶柱体阵列结构的柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
在根据本发明的用于AR设备的光波导装置中，可选地，所述三阶柱体阵列结构的三阶柱体的表面至少在三个方向具有高度下降的梯度，其中，第一个方向是第二光栅耦入光线的传输方向，第二个方向是第二光栅左侧转折光线的传输方向，第三个方向是第二光栅右侧转折光线的传输方向。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体设置成相对于所述第一柱体朝向所述第一光栅所在的方向偏置。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体的底面关于所述第一柱体的底面相切，并且相切点位于所述第二柱体的偏置方向上。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二柱体的底面是按照所述第一柱体的底面以预设的缩小率进行等比例缩小。
在根据本发明的用于AR设备的光波导装置中，可选地，所述缩小率的范围是0.45-0.65。
在根据本发明的用于AR设备的光波导装置中，可选地，在所述第二光栅单元阵列的第一维度方向和第二维度方向上组成的二维平面内，所述第二柱体在该二维平面内的投影至少在三个方向小于与其相对应的第一柱体在该二维平面内的投影。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一高度的范围为30nm-65nm，并且所述第二高度与所述第一高度具有基本上相当的高度。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第二光 栅单元阵列设置成从所述耦出区的外表面向外凸出或者向内凹进，并且所述第一光栅单元阵列设置成从所述耦入区的外表面向外凸出或者向内凹进。
在根据本发明的用于AR设备的光波导装置中，可选地，所述第一光栅包括闪耀光栅、倾斜光栅和二元光栅。
在根据本发明的用于AR设备的光波导装置中，可选地，所述光波导基底的厚度为0.3mm-2.5mm，折射率为1.4-2.2。
另外，根据本发明的第五方面，进一步提供了一种AR设备，其中，所述AR设备包括：
一个或多个如以上任一项所述的用于AR设备的光波导装置；以及
投像装置，其布置在所述光波导装置的入光侧用于发送出图像光线，使其入射至所述光波导装置的耦入区。
另外，根据本发明的第六方面，进一步提供了一种用于AR设备的光波导装置的制造方法，其中，所述制造方法包括步骤：
提供光波导基底；
设置具有第一光栅的耦入区，所述第一光栅具有耦入光栅矢量并使得入射光线耦入所述光波导基底内；以及
设置具有第二光栅的耦出区，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量并且将来自所述光波导基底的光线二维扩展后耦出，其中所述第二光栅的光栅单元阵列与所述第一光栅的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形，
其中，将所述第二光栅构造成二维表面浮雕光栅，该二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在 垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，将所述第一光栅构造成具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，并且将所述第二光栅构造成具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
P0＝Py，并且s＝k*Px
其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述三阶柱体阵列结构的柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
在根据本发明的用于AR设备的光波导装置的制造方法中，可选地，所述三阶柱体阵列结构的三阶柱体的表面至少在三个方向具有高度下降的梯度，其中，第一个方向是第二光栅耦入光线的传输方向，第二个方向是第二光栅左侧转折光线的传输方向，第三个方向是第二光栅右侧转折光线的传输方向。
采用本发明技术方案，不仅能够使得光波导装置易于实现二维扩瞳，而且不局限于等边三角形的光栅阵列排布，从而有利于提升现有的光波导片设计自由度，促使产品结构更加紧凑化和轻巧化，并且可使得视场角范围更大，耦出光线与耦入光线的方向基本一致而易于实现基本无像差的投射图像显示。此外，本发明能有效降低由于透射到世界侧的衍射级而带来的光能损失，从而有利于加强用户侧的衍射效率，提升AR设备的续航能力。根据本发明的光波导装置和AR设备结构简单且紧凑，非常适于进行批量化生产，其具有良好的工业应用价值。
附图说明
以下将结合附图和实施例对本发明的技术方案作进一步的详细描述，但是应当知道，这些附图仅是出于解释目的进行阐释，因此不必按照比例进行绘制。
图1是一个根据本发明的光波导装置实施例的立体结构示意图。
图2是图1所示的光波导装置实施例的侧视结构示意图，其中也示意性地图示出了微投影仪和人眼。
图3是一个现有技术中的普通柱体阵列的结构示意图。
图4是图1所示的光波导装置实施例中的第二光栅的柱形光栅单元阵列示例的结构示意图。
图5示出了在图1所示的光波导装置实施例中分别与耦入光栅元素H0、耦出光栅元素H1和H2相对应的耦入光栅矢量G0、耦出光栅矢量G1和G2，这些光栅矢量G0、G1和G2此时形成了等腰三角形。
图6示出了在该光波导装置实施例中分别与耦入光栅元素H0、耦出光栅元素H3相对应的耦入光栅矢量G0、耦出衍生光栅矢量G3。
图7是光线在该光波导装置实施例中的光传输路径示意图。
图8是图7所示的光传输路径在xoy平面内的主视图。
图9示出了由标准光栅元素H1提供来自于第一光栅所传输光信号的第一水平视场角Fx1。
图10示出了由标准光栅元素H2提供来自于第一光栅所传输光信号的 第二水平视场角Fx2。
图11示出了该光波导装置实施例中的第二光栅在三种不同的二维周期比下所支持视场范围的相应曲线图。
图12示出了具有大视场的光波导装置实施例的K矢量图。
图13示出了三种不同的二阶单元阵列示例。
图14示出了每次图像光线被光波导装置实施例中的第二光栅耦出时同时产生向外的透射衍射级T1和向内的反射衍射级R1的情形。
图15示出了在该光波导装置实施例中的第二光栅选用二阶柱形单元阵列时，其中柱体底面呈现为关于y轴对称的凸六边形。
图16示出了基于傅里叶模式法仿真得到的在采用二阶六边形单元阵列的第二光栅中传输的s偏振光、p偏振光的各自透射衍射级T1、反射衍射级R1随着入射角β变化的耦出衍射效率曲线。
图17示出了用于第二光栅的分别具有不同底面柱体的三阶光栅单元示例的相应结构。
图18是图17中所示的示例(c)的三阶六边形柱体单元结构的不同视图。
图19示出了将图18所示的三阶六边形柱体结构排列成二维光栅单元阵列耦出光栅时的情形。
图20示出了图18所示的二维光栅单元阵列耦出光栅中传输的s偏振光、p偏振光的各自透射衍射级T1、反射衍射级R1随着入射角β变化的耦出衍射效率曲线。
图21至图24分别示出了在图18所示的二维光栅单元阵列耦出光栅中的三阶柱体总高d＝80nm时，s偏振光与p偏振光的各自透射衍射级T1和反射衍射级R1的衍射效率随着缩小率v和第一高度d1变化的函数关系。
图25至图28分别示出了在图18所示的二维光栅单元阵列耦出光栅中的三阶柱体总高d＝100nm时，s偏振光与p偏振光的各自透射衍射级T1和反射衍射级R1的衍射效率随着缩小率v和第一高度d1变化的函数关系。
图29至图32分别示出了在图18所示的二维光栅单元阵列耦出光栅中的三阶柱体总高d＝120nm时，s偏振光与p偏振光的各自透射衍射级T1和反射衍射级R1的衍射效率随着缩小率v和第一高度d1变化的函数关系。
图33是一个根据本发明的光波导装置的制造方法实施例的流程图。
具体实施方式
首先，需要说明的是，以下将以示例方式来说明根据本发明的用于AR设备的光波导装置及其制造方法和AR设备的步骤、构造、特点以及优点等，然而所有的描述不应当用来对本发明构成任何限制。在本文中，技术术语“第一”、“第二”仅是用于进行区分性表述目的而无意于表示它们的顺序和相对重要性等，技术术语“基本上”旨在包括与特定量的测量相关联的非实质性误差，例如可以包括给定值的±8％、±5％或±2％等范围，技术用语“上”、“下”、“右”、“左”、“水平”、“竖直”及其派生词应联系各附图中的定向，并且应理解本发明可以采取多种替代定向，。
此外，对于在本文的实施例中予以描述或隐含的任意单个技术特征，或者被显示或隐含在各附图中的任意单个技术特征，本发明仍然允许在这些技术特征(或其等同物)之间继续进行任意组合或者删减而不存在任何的技术障碍，从而涵盖了根据本发明的更多实施例。另外，为了简洁起见，相同或相类似的零部件和特征在同一附图中可能仅在一处或若干处进行标示，并且在本文中也不多赘述已被本领域技术人员公知的一般事项。
请参阅图1、图2和图7，在这些中以示意方式大致示出了一个根据本发明的光波导装置实施例的基本构造及工作情况，非常适合将其装设应用于AR设备。如图所示，在这个实施例中，该光波导装置被构造成基本上呈片状，并且包括光波导基底1、耦入区2和耦出区3。光波导基底1对于可见光是透明的，它通常可具有两个相对的光学平面。在本实施例中，光波导基底1将对进入其内部的图像光线进行全反射传输，可以将它的厚度可选地设置为0.3mm-2.5mm，折射率为1.4-2.2。总体来讲，在本发明中适宜优先采用轻薄、大折射率的光波导基底。
如图1所示，可以将耦入区2布置在光波导基底1的一端，并且可在该耦入区2中设置第一光栅(或称为耦入光栅)，以便用来将接收到的入射光线(例如图2中所示的来自于微投影仪4的图像光线)耦入到光波导基底1，进而实现在光波导基底1内的全反射传输。在本实施例中，第一光栅可采用一维表面浮雕光栅，可以将光栅槽设置成平行于x轴，例如图1中所示。作为可选情形，为了实现尽可能高的耦合效率，第一光栅以采用闪耀光栅、倾斜光栅、二元光栅等为宜。
对于耦出区3，可将其布置在光波导基底1的另一端，并且可以在该耦出区3中设置第二光栅(或称为耦出光栅)，以便用来将经由耦入区2进入光波导基底1的光线进行二维扩展，并使其沿着z轴方向耦出光波导基底1，进而可衍射进入人眼5。在本实施例中，第二光栅可采用二维表面浮雕光栅，以便用来与上述的第一光栅形成配合作用，随后将会对此展开详细说明。
在图3中示意性地阐释了一个现有技术中的普通柱体阵列结构，其具有在x轴方向上的水平周期Px、在y轴方向上的竖直周期Py以及行偏移量s。关于行偏移量s，其被定义为阵列结构的奇数行与偶数行在x轴方向上存在的偏移，例如在该图3中显示为行偏移量s＝0。
本案发明人经过大量研究分析后发现，为了能够实现图像光线的有效二维扩展和耦出，当将第二光栅中的行偏移量s设置为它的水平周期Px的0.45-0.55倍并将它的竖直周期Py设置成等于第一光栅的周期P0时，将会获得相当良好的技术效果，并且当将行偏移量s设置为水平周期Px的一半时是最有效的，在图4中非常清楚地显示了此时的柱体阵列结构。对于第二光栅中经偏移后的柱体阵列结构，可将其视为由两个倾斜周期结构h1与h2进行叠加的结果，栅线与y轴之间存在夹角θ，同时其在y轴方向上的竖直周期结构由于偏移原因而遭到了破坏，然而可将第一行与第二行共同视为新的周期结构h3，其周期为Py的两倍。在实际应用时，可以将以上光栅周期P0可选地设置为足够小，以便促使入射光线对应的衍射一级能够更好地满足全反射条件而被光波导基底1捕获，例如可将周期P0的取值范围设置为250nm-500nm。
在图5和图6中分别示出了可以针对第一光栅和第二光栅的各自周期结构设定的相应的光栅矢量，其中在图5中示出了在光波导装置上与耦入光栅元素H0、耦出光栅元素H1和H2分别对应的耦入光栅矢量G0、耦出标准光栅矢量G1和G2，在图6中则示出了在光波导装置上与耦入光栅元素H0、耦出光栅元素H3分别对应的耦入光栅矢量G0、耦出衍生光栅矢量G3。具体来讲，第一光栅和第二光栅的这些光栅矢量可以位于光栅栅线所在平面内，并且可在与光栅栅线方向成直角的方向上延伸，光栅矢量的量值可以例如由表达式G＝2π/d给出，其中d是光栅的周期(即，相邻的光栅槽之间的节距)。虽然耦入光栅与耦出光栅在空间上是彼此分离的，但是由于光栅矢量具有空间平移不变的特性，因此可以将这些光栅矢量叠加连接在一起。
在图1实施例中，使用了微投影仪3用来向该光波导装置投射图像光线，对于图像光线每次受到的光栅衍射转折作用，可以用光栅矢量与光波矢的矢量叠加来表示。光波导装置在完成图像传输时需要满足消色差成像条件，即不同波长不同角度入射的图像光线在经其扩散传输最终耦出后，出射光的方向与入射光应保持一致，这就要求出射光波矢能够与入射光波矢保持一致。因此，多个光栅的衍射转折作用需要在光波导装置的工作面内相互抵消，其表现为这些光栅矢量的叠加之和等于零，或者基本上为零，这可以例如以低于某个根据应用需要所设定的阈值作为判定标准。
如果要求完全满足上述的消色差成像条件，那么就要限定如下关系：P0＝Py，并且s＝Px/2。下面将就此来说明这是光栅矢量叠加之和为零的充分条件。可以知道的是，耦出光栅元素H1、H2的栅线与y轴之间的夹角为θ，因此耦出标准光栅矢量G1、G2与x轴之间的夹角同样为θ，并且存在以下关系：
Figure PCTCN2021115048-appb-000001
对于耦出标准光栅矢量G1和G2的大小，可以按照以下关系式进行计算：
Figure PCTCN2021115048-appb-000002
进而，可以将耦出标准光栅矢量G1和G2二者的叠加矢量表示为：
Figure PCTCN2021115048-appb-000003
由此，可以将耦入光栅矢量G0表示为：
Figure PCTCN2021115048-appb-000004
如此，正如图5所示，此时可以由以上这些光栅矢量G0、G1、G2围成一个等腰三角形而不必再局限于等边三角形，并且不产生额外的合成矢量，同时也使得消色差成像条件得以满足。当然，在一些实施方式下，还可以考虑将行偏移量s设置为周期Px的k倍(k≠0.5但取值于0.45-0.55范围内)，尽管此时的消色差成像不是最佳的，但是也可以获得较好的效果，从而能够充分、灵活地满足各种不同的应用需要。
本发明通过采用例如以上建议的这些光栅设置和组合方式，能够在基本上没有角度或色度偏移的情况下实现光的耦合输出。由于第二光栅的两个耦出标准光栅矢量G1和G2彼此交叉，并且相对于第一光栅的耦入光栅矢量G0形成对称布置，从而它们可以一起形成为等腰三角形，这种不局限于等边三角形的光栅阵列排布对于提高光波导装置的设计自由度、紧凑度等方面都是非常有利的。第二光栅对于入射光的二维扩展是对称的，它的两个耦出标准矢量可以在对入射光进行两次衍射作用之后输出光波导装置，并且其输出方向与输入方向一致，以上这种作用是与波长无关的，因此可以方便地实现彩色显示。
当第二光栅采用二维表面浮雕光栅时，不能将二维浮雕光栅所具有的衍射特性仅仅视为耦出光栅元素H1与H2的叠加。事实上，当来自第一光栅的光线经由光波导基底1进入第二光栅时，沿着y轴方向周期排列的衍生光栅H3同样会将光束耦合出该光波导装置。作为一种优选情形考虑，这部分出射光束也可被要求满足消色差条件。可以将衍生光栅H3的光栅矢量G3表示为:
Figure PCTCN2021115048-appb-000005
由此可见，当衍生光栅矢量G3的大小为耦入光栅矢量G0的一半时是 效果最佳的，当然在将二者大小比例设置在0.45-0.55范围内时也能够实现较好的效果。在衍生光栅H3对应的二级衍射光栅矢量是衍生光栅矢量G3的两倍时，它的二级衍射光栅矢量与耦入光栅矢量的叠加之和等于零，正如图6中所示，光栅矢量经过两个衍生光栅矢量G3的叠加后返回到原点，从而满足了消色差成像条件。
图7是光线在该光波导装置实施例中的光传输路径示意图，并且图8是图7所示的光传输路径在xoy平面内的主视图。如图7和图8所示，当来自第一光栅的图像光线入射到第二光栅上时，通过后者所包含的不同光栅元素的作用将会同时产生多个不同的衍射，其中，光在第二光栅的点A处被接收并将同时经历四次衍射。
具体来讲，耦入光线O在点A处被接收到后，它首先将被衍生光栅元素H3直接以-2级a1耦出光波导装置，沿着z轴方向朝向观察者的眼睛传输。
然后，在点A接收到的光会被衍射成零级a2，这是入射光传播方向的延续。零级光a2被分配了大部分光能量，它可以继续前往点B和位于同一路径上随后的各作用点，并且在这些点处进一步产生类似于点A的衍射作用。
第三，在点A接收到的光还与标准光栅元素H1相互作用生产一级侧向衍射光a3，其会在与x轴成θ角(与图4中的θ角一致)的方向上衍射，并且在点C处继续与二维光栅中的标准光栅元素H2发生相互作用，从而产生耦出衍射级c1。由于c1依次经历了以上三个光栅元素H0、H1、H2的衍射作用，从而使得对应叠加的光栅矢量G0、G1、G2产生了抵消作用，因此衍射级c1的角度特性与色度特性将与耦入光线O保持一致。入射在点C处的光，还将与标准光栅元素H1相互作用而使得与在点A处的标准光栅元素H1的作用相互共轭，对应于叠加了两个相反方向的标准光栅矢量G1而产生了朝向点F的衍射级次c3，并且c3的传输方向与A点处的耦入光线O保持一致。光线c3将沿着-y轴方向在点F和位于同一路径上随后的各作用点上进一步产生类似于点A的衍射作用。此外，入射在点C处的零级光c2将继续沿着与x轴成θ角的方向在E点和位于同一路 径上随后的作用点上进一步产生类似于点C的衍射作用。
第四，在点A接收到的光还与标准光栅元素H2相互作用生产一级侧向衍射光a4并向点D传输。由于标准光栅元素H2与H1二者相对于y轴存在对称性，因此a4的后续衍射传输路径也与a3对称。该路径产生了朝向光波导装置左侧的扩散与耦出。在经过一系列的衍射与传输之后，最终可以在光波导装置的耦出区左右两侧同时耦出光线，从而通过观察者的眼睛可以在上述区域内的任意位置处观察到完整连续的图像。
应当说明的是，为了简洁起见，在以上示范性描述中限制了所讨论的光学路径的数量，并且在图7和图8中所示的光传输路径是以沿着z轴方向耦入的光线为例展开说明的，事实上，当耦入光线与z轴之间成一定角度入射时，类似的光学路径也是同样可行的。但是，如果耦入光线与yoz面之间角度过大的话，那么侧向衍射光线a3或a4将会由于不能满足有效的全反射传输而消逝，而剩下的一个侧向衍射光所对应的标准光栅元素则保留了对该部分角度的耦入光线进行有效衍射与传输的能力。
再请参阅图9和图10，它们分别示出了由标准光栅元素H1和H2各自提供来自于第一光栅所传输光信号的第一水平视场角Fx1和第二水平视场角Fx2的情况。如图9所示，标准光栅元素H1可以提供来自于第一光栅所传输光信号的第一水平视场角Fx1，在第一光栅处接收到的光信号将会以衍射光a3传输到第二光栅所包含的另一个标准光栅元素H2上，后者则会作为输出衍射光学元件，将光从光波导装置耦合提供给观察者。再如图10所示，标准光栅元素H2可以提供来自于第一光栅所传输光信号的第二水平视场角Fx2，在第一光栅处接收到的光信号将会以衍射光a4传输到第二光栅所包含的另一个标准光栅元素H1上，后者则会作为输出衍射光学元件，将光从光波导装置耦合提供给观察者。
虽然第一水平视场角Fx1与第二水平视场角Fx2部分地重叠，但是它们相对于彼此包含另一个对方不包含的角度。显然，如果非重叠部分的视场角越大，那么第二光栅所支持的总视场角Fx也将越大。在图9和图10中，Fy是沿着y轴方向被传输的图像光线视场角，它将会受到波导材料折射率的限制。本发明已经发现，如果将第二光栅的竖直周期Py与水平 周期Px二者设置成不同的比值，这将会对所支持的水平总视场角Fx产生显著影响。
举例而言，例如在一个实施方式下，可以将光波导基底1设置成折射率1.7且厚度1mm的光学平板玻璃，第一光栅周期P0为340nm，第二光栅的水平周期Px为392.6nm，竖直周期Py为340nm，其二维周期比w＝Py/Px＝0.866，水平偏移量s为196.3nm，并且采用460nm的蓝光作为耦入光源。在图11中，由图中所示的圆点曲线与y轴所包围形成的区域限定了该光波导装置的半视场范围。
又比如，在另一个实施方式下，可以将光波导基底1设置成折射率1.7且厚度1mm的光学平板玻璃，第一光栅周期P0为340nm，第二光栅的水平周期Px为360nm，竖直周期Py为340nm，其二维周期比w＝Py/Px＝0.944，水平偏移量s为180nm，并且采用460nm的蓝光作为耦入光源。在图11中，由图中所示的星点曲线y轴所包围形成的区域限定了该光波导装置的半视场范围。
再比如，在又一个实施方式下，可以将光波导基底1设置成折射率1.7且厚度1mm的光学平板玻璃，第一光栅周期P0为340nm，第二光栅的水平周期Px为340nm，竖直周期Py为340nm，其二维周期比w＝Py/Px＝1，水平偏移量s为170nm，并且采用460nm的蓝光作为耦入光源。在图11中，由图中所示的四方点曲线y轴所包围区域限定了该光波导装置的半视场范围。
可以理解的是，由于光波导装置的视场是关于y轴对称的，因此图11中显示出的是光波导装置的实际水平方向视场范围的一半。当耦入光线的视场角超过由图11中所示曲线与y轴所包围的范围时，耦出光线或者会消逝，或者会产生额外的耦出衍射级次，从而将影响耦出图像的质量。从图11可以看出，随着第二光栅的二维周期比w的逐渐增大，其支持的视场范围在竖直方向几乎没有变化，而水平方向则逐渐地扩增。在二维周期比w等于1时的水平方向视场角相比于w等于0.866时的水平方向视场角增大了约65％。因此可以相信，随着二维周期比w的进一步增大，水平方向视场范围可进一步扩增。然而，如果二维周期比w相对过大，那么光 波导装置相邻的出瞳将会产生过大的间距，从而不利于出瞳光能量的连续分布，并且不利于光波导装置耦出图像的均匀性；与此相反，如果二维周期比w相对过小，那么有可能会难以支持较大的视场角。因此，根据本案发明人的研究结果，将二维周期比w可选地设置在0.7-1.2的范围被认为是有利的。
请继续参阅图12，其中示出了具有大视场的光波导装置示例的K矢量图。在图12中，圆O1表示光波导装置被最小全反射角所限制的传输角度下限，圆O2表示光波导装置内由传输模式决定的传输角度上限，环形阴影区域表示可有效传输视场角的角度空间区域，F1表示由投影光机投射出的准直光所对应的投射视场折射入光波导装置内所对应的传输视场，P1表示由耦入光栅元素H0产生衍射作用后将传输视场F1变为传输视场F4，P2表示由标准光栅元素H1产生衍射作用后将传输视场F4的一部分变为传输视场F3，P4表示由标准光栅元素H2产生衍射作用后将传输视场F3耦出光波导装置而离开有效传输区域，P3表示由标准光栅元素H2产生衍射作用后将传输视场F4的一部分变为传输视场F2，P5表示由标准光栅元素H1产生衍射作用后将传输视场F2耦出光波导装置而离开有效传输区域。位于两侧的部分视场在离开光波导装置之后，将会再次结合成完整的视场F1，然后被观察者的眼睛所接收。
在图13中仅以示例方式展示了可以用于第二光栅的若干个二阶单元阵列示例。例如，可以采用图中示例(a)所示的二阶矩形单元阵列、示例(b)所示的凹多边形单元阵列、示例(c)所示的二阶凸多边形(包含一个大于180°的内角)单元阵列，当然本发明也允许采用例如椭圆单元阵列等其他任意形状的单元阵列，或者甚至是一些组合图形的单元阵列。另外，应指出的是，这些单元阵列结构可以是柱体形状，其在本文中具有广泛含义，例如涵盖了诸如棱锥、棱台、半球、斜棱柱等众多的相对简单或者相当复杂的构型，采用这些不同的结构形状仅能改变二维光栅不同衍射级次的能量分配，而不会改变光传输路径。此外，还应说明的是，这些单元阵列结构可以凸出于基底材料表面，也可以凹陷于基底材料表面，其上方可以有镀膜层或者可以是空气环境，但在单元阵列结构两侧形成折射 率差异是产生衍射的必要条件。根据本发明的以上教导内容，本领域技术人员应该理解，对于光波导装置中的第二光栅实际上存在着大量合适的结构形状。
如图14所示，在将光波导装置装设到AR设备上后，当来自于光波导装置的图像光线朝向观察者的眼睛耦合输出时，每次耦出的图像光线将会同时产生向外的透射衍射级T1(也常称为世界侧)和向内的反射衍射级R1(也常称为用户侧)。通常来讲，需要将更多的图像光线指向用户侧而不是世界侧，这些因为指向世界侧的图像光线不仅本质上是浪费的，而且还会让位于观察者周围的其他人群不必要地看到输出的内容。因此，获得一个相对较小的一级透射衍射光和一个相对较大的一级反射衍射光，这将是有利的。
本发明已经发现，对于二阶柱形单元阵列耦出光栅来讲，其一级反射R1与一级透射T1的衍射效率是基本上接近的。在一些实施方式下，第二光栅单元阵列可以选用例如图15所示的柱体底面为关于y轴对称的凸六边形。作为举例说明，可以将第二光栅单元阵列设置成其水平方向周期Px＝335nm，竖直方向周期Py＝335nm，光槽深(柱高)＝73nm，水平偏移量s＝167.5nm，那么如图15中所示的该凸六边形周围的棱形虚线限定了柱体所在的单位结构，其中的线段C0D0＝Px，线段A0B0＝2*Py，另外四条边A1E1、A1E2、B1E3和B1E4分别与棱型的边相平行，另外两条边E1E3和E2E4分别与y轴相平行，线段A1B1与线段A0B0的长度比u＝0.8(即填充因子)，线段E1E3与线段A1B1的长度比u＝0.65。在该示例中，可以采用460nm蓝光作为耦入光源，并对应采用折射率为1.7的光波导基底。入射光线在xoy平面内沿着图中的AC(或AD)方向进行传输，该入射光线可与z轴之间形成入射角β。
请继续参阅图16，在该图中进一步给出了基于傅里叶模式法仿真得到的在采用二阶六边形单元阵列的第二光栅中传输的s偏振光、p偏振光的各自透射衍射级T1、反射衍射级R1随着入射角β变化的耦出衍射效率曲线。从图16中可以获知，在任意偏振态的同一角度下R1与T1在数值上相当，因此二阶柱形单元阵列耦出光栅将会浪费大量光能于世界侧， 这种情况对于通常紧凑轻巧的消费级AR系统来讲，大量光能浪费对续航是极为不利的。对此，本发明已经找到并且提出了能够解决以上问题的有效手段。
作为举例说明，例如在一些实施方式下，可以将光波导装置中的第二光栅可选地设置成例如三阶或以上的高阶柱状阵列结构。根据本发明的研究分析表明，采用此类高阶柱状阵列结构可以有效降低由于透射到世界侧的衍射级带来的光能损失。
一般而言，如果柱状阵列光栅的阶数越高，那么它的闪耀特性越显著，但是考虑到加工容易性、成本等因素限制，作为一种可选情形，可考虑将第二光栅构造为三阶柱状阵列结构，使其包括从波导表面伸出的多个第一柱体11和多个第二柱体12，这些柱体排列成二维周期阵列，并且第一柱体11中的每一个在垂直波导表面的方向上具有第一高度d1，第二柱体12中的每一个从第一柱体11上表面伸出并具有第二高度d2，在根据本发明的方案中对于第二高度d2和第一高度d1二者之间的关系没有特定限制，例如通常可考虑将它们设置成具有基本上相当的高度，即本领域技术人员可以理解的是，只要使得两者在高度尺寸量级上大致相当，不要高度相差太大即可。第二柱体12的底面通常也比第一柱体11的底面小，因此其下表面将被包含在第一柱体11的上表面内。第二柱体12可相对于第一柱体11偏置，偏置方向为耦入光栅所在的方向。在可选情况下，可以将第二柱体12构造成其底面按照第一柱体11的底面等比例缩小，另外还可以使得第二柱体12底面关于第一柱体11底面相切，相切点位于上述的偏置方向上。
在图17中分别给出了可用于第二光栅的若干个采用不同底面柱体的三阶光栅单元。如图中所示，这些三阶柱体示例(a)、(b)和(c)的表面可以至少在三个方向具有高度下降的梯度，其中第一个方向是第二光栅耦入光线的传输方向(请参阅图15中的AB方向)，第二个方向是第二光栅左侧转折光线的传输方向(请参阅图15中的AD方向)，第三个方向是第二光栅右侧转折光线的传输方向(请参阅图15中的AC方向)。
在图18中进一步提供了图17中所示的三阶柱体示例(c)的不同视图。 如图中所示，第一柱体11的底面与图15所示的六边形基本上一致，其第一高度d1＝50nm，填充因子u＝0.8，其第二柱体12底面为等比例缩小率v＝50％的六边形，其第二高度d2＝50nm，并且在+y轴方向上偏置，因此沿着xoy平面内的方向D1(图15中的AB方向)存在第一个高度下降的梯度，例如侧视图(a)所示，并且沿着xoy平面内的方向D2(图15中的AC方向)存在第二个高度下降的梯度，如侧视图(b)所示，而且还沿着xoy平面内的方向D3(图15中的AD方向)存在第三个高度下降的梯度，例如侧视图(c)所示，由于以上这些梯度的存在，因此可以在多个方向上形成类似闪耀光栅所具备的闪耀效果，从而能够有效加强用户侧的衍射效率，减小世界侧的衍射效率，从而减少光能损失，有利于提高AR设备的续航能力。
继续参考图19，其中示意性地图示出了将图18所示的三阶柱体结构排列成二维光栅单元阵列耦出光栅。作为示例说明，可以将该光栅单元阵列设置成其水平方向周期Px＝335nm，竖直方向周期Py＝335nm，水平偏移量s＝167.5nm，即排列方式与图15所示的二阶柱形单元阵列相一致，以便用来进行对比。
在图20中示出了在采用了上述三阶光栅单元阵列中传输的s偏振光、p偏振光的各自透射衍射级T1、反射衍射级R1随着入射角β变化的耦出衍射效率曲线，其中入射光使用460nm蓝光，它在xoy平面内沿着如图15中所示的AC(或AD)方向进行传输。如图20所示，在同一偏振态下，面向用户侧的反射级R1的衍射效率能达到世界侧的透射级T1的2-3倍。由此可见，采用根据本发明的以上方案，可以使得反射级R1得到了极大加强从而提升了用户端的衍射效率，并且对透射级T1进行了有效抑制。
如前所述，根据本发明方案可实现对高阶二维耦出光栅的设计优化，从而能够实现进一步增强用户侧的衍射效率，并且减弱世界侧的衍射效率的良好效果。在图21至图32中分别示出了对于采用了上述三阶光栅单元阵列的第二光栅示例的衍射效率的进行优化仿真的情况。
具体来讲，图21至图24分别示出了在该第二光栅示例中的三阶柱体总高d＝d1+d2＝80nm时，s偏振光与p偏振光的各自透射衍射级T1和反射 衍射级R1的衍射效率随着缩小率v和第一柱体的第一高度d1变化的函数关系。
图25至图28分别示出了在该第二光栅示例中的三阶柱体总高d＝100nm时，s偏振光与p偏振光的各自透射衍射级T1和反射衍射级R1的衍射效率随着缩小率v和第一高度d1变化的函数关系。
图29至图32分别示出了在该第二光栅示例中的三阶柱体总高d＝120nm时，s偏振光与p偏振光的各自透射衍射级T1和反射衍射级R1的衍射效率随着缩小率v和第一高度d1变化的函数关系。
如以上这些图21至图32中所示，在由图面中的椭圆所标示区域内，用户侧的衍射效率较强，而世界侧的衍射效率则较低。另外，还可以发现在不同偏振态下，不同的三阶柱体总高d在一定范围内对于椭圆所在区域的影响并不显著，此时在该区域内缩小率v大概在0.45-0.65的范围内，第一高度d1大概在30nm-65nm的范围内。
根据本发明的一个技术方案，还提供了一种AR设备，可以在该AR设备上配置一个或多个以上讨论的根据本发明的光波导装置，并且通过将投像装置设置在光波导装置的入光侧，以便向其发送图像光线而入射到光波导装置的耦入区。由于采用了如前所述的第一光栅和第二光栅的相应设置与组合，因此可以使得AR设备在基本上没有角度或色度偏移的情况下提供光的耦合输出，不仅易于实现二维扩瞳，并且设计自由度更高，视场角范围更大，而且能够有效减少透射衍射光以提高能效，提升AR设备的续航能力和产品竞争力。
此外，根据本发明的另一个技术方案，还提供了用于AR设备的光波导装置的制造方法，其易于量产加工，并且生产效率较高，因此具有很强的工业应用价值。作为示范性说明，请参阅图33，在这个实施例中给出了关于制造本发明的光波导装置的大致步骤。
具体来讲，首先在步骤S11中，可以提供光波导基底；
然后，可以在步骤S12中设置具有第一光栅的耦入区，例如可以将该耦入区设置在光波导基底的一端，第一光栅具有耦入光栅矢量并且使得入射光线耦入该光波导基底内；
在步骤S13中，可以设置具有第二光栅的耦出区，例如可以将该耦出区设置在光波导基底的另一端，第二光栅具有相互交叉的第一耦出光栅矢量和第二耦出光栅矢量，并且将来自该光波导基底的光线进行二维扩展后耦出，其中第二光栅的光栅单元阵列与第一光栅的光栅单元阵列在一个维度方向上基本上平行并且二者周期相同，第一耦出光栅矢量和第二耦出光栅矢量具有基本上相等的量值，并且它们相对于耦入光栅矢量相互对称设置，从而可以由第一耦出光栅矢量、第二耦出光栅矢量以及耦入光栅矢量三者一起形成一个等腰三角形。
如前所述，由于在前文关于本发明的用于AR设备的光波导装置以及AR设备示例的介绍中已经针对光波导装置的结构构造、组成、配置、特性等诸多情况进行了详细介绍，因此在本发明方法中可以直接参阅前述相应部分的具体说明，不在此重复描述。
以上仅以举例方式来详细阐明根据本发明的用于AR设备的光波导装置及其制造方法和AR设备，这些个例仅供说明本发明的原理及其实施方式之用，而非对本发明的限制，在不脱离本发明的精神和范围的情况下，本领域技术人员还可以做出各种变形和改进。例如，尽管AR设备中的光波导装置普遍采用整体片状结构，但是本发明中的光波导装置允许采用任何适宜的结构形式，例如在一些情形下可允许其在局部形成凸块等形状。因此，所有等同的技术方案均应属于本发明的范畴并为本发明的各项权利要求所限定。

Claims (44)

  1. 一种用于AR设备的光波导装置，其包括光波导基底、耦入区和耦出区，所述耦入区设有第一光栅用以将入射光线耦入所述光波导基底内，所述耦出区设有第二光栅用以将来自所述光波导基底的光线二维扩展后耦出，所述第一光栅具有耦入光栅矢量，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量，其特征在于，所述第一光栅和所述第二光栅各自的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量具有基本上相等的量值，并且相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形。
  2. 根据权利要求1所述的用于AR设备的光波导装置，其中，所述第一光栅具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，所述第二光栅具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
    P0＝Py，并且s＝k*Px
    其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
  3. 根据权利要求2所述的用于AR设备的光波导装置，其中，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
  4. 根据权利要求1至3中任一项所述的用于AR设备的光波导装置，其中，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
  5. 根据权利要求1至4中任一项所述的用于AR设备的光波导装置，其中，所述第二光栅是二维表面浮雕光栅，所述第二光栅单元阵列具有二 阶或者更高阶柱体阵列结构，所述柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
  6. 根据权利要求5所述的用于AR设备的光波导装置，其中，所述二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
    多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
    多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
  7. 根据权利要求6所述的用于AR设备的光波导装置，其中，所述第二柱体设置成相对于所述第一柱体朝向所述第一光栅所在的方向偏置。
  8. 根据权利要求7所述的用于AR设备的光波导装置，其中，所述第二柱体的底面关于所述第一柱体的底面相切，并且相切点位于所述第二柱体的偏置方向上。
  9. 根据权利要求6、7或8所述的用于AR设备的光波导装置，其中，所述第二柱体的底面是按照所述第一柱体的底面以预设的缩小率进行等比例缩小。
  10. 根据权利要求9所述的用于AR设备的光波导装置，其中，所述缩小率的范围是0.45-0.65。
  11. 根据权利要求9所述的用于AR设备的光波导装置，其中，在所述第二光栅单元阵列的第一维度方向和第二维度方向上组成的二维平面内，所述第二柱体在该二维平面内的投影至少在三个方向小于与其相对应的第一柱体在该二维平面内的投影。
  12. 根据权利要求6至11中任一项所述的用于AR设备的光波导装置，其中，所述第一高度的范围为30nm-65nm，并且所述第二高度与所述第一高度具有基本上相当的高度。
  13. 根据权利要求1-12中任一项所述的用于AR设备的光波导装置， 其中，所述第二光栅单元阵列设置成从所述耦出区的外表面向外凸出或者向内凹进，并且所述第一光栅单元阵列设置成从所述耦入区的外表面向外凸出或者向内凹进。
  14. 根据权利要求1-13中任一项所述的用于AR设备的光波导装置，其中，所述第一光栅包括闪耀光栅、倾斜光栅和二元光栅。
  15. 根据权利要求1-14中任一项所述的用于AR设备的光波导装置，其中，所述光波导基底的厚度为0.3mm-2.5mm，折射率为1.4-2.2。
  16. 一种AR设备，其特征在于，所述AR设备包括：
    一个或多个如权利要求1-15中任一项所述的用于AR设备的光波导装置；以及
    投像装置，其布置在所述光波导装置的入光侧用于发送出图像光线，使其入射至所述光波导装置的耦入区。
  17. 一种用于AR设备的光波导装置的制造方法，其特征在于，所述制造方法包括步骤：
    提供光波导基底；
    设置具有第一光栅的耦入区，所述第一光栅具有耦入光栅矢量并使得入射光线耦入所述光波导基底内；以及
    设置具有第二光栅的耦出区，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量并且将来自所述光波导基底的光线二维扩展后耦出，其中所述第二光栅的光栅单元阵列与所述第一光栅的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量具有基本上相等的量值并且相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形。
  18. 根据权利要求17所述的用于AR设备的光波导装置的制造方法，其中，将所述第一光栅构造成具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，并且将所述第二光栅构造成具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
    P0＝Py，并且s＝k*Px
    其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
  19. 根据权利要求18所述的用于AR设备的光波导装置的制造方法，其中，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
  20. 根据权利要求17所述的用于AR设备的光波导装置的制造方法，其中，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
  21. 根据权利要求17-20中任一项所述的用于AR设备的光波导装置的制造方法，其中，将所述第二光栅构造成二维表面浮雕光栅，所述第二光栅的第二光栅单元阵列包括二阶或者更高阶柱体阵列结构，所述柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
  22. 根据权利要求21所述的用于AR设备的光波导装置的制造方法，其中，所述二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
    多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
    多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
  23. 一种用于AR设备的光波导装置，其包括光波导基底、耦入区和耦出区，所述耦入区设有第一光栅用以将入射光线耦入所述光波导基底内，所述耦出区设有第二光栅用以将来自所述光波导基底的光线二维扩展后耦出，所述第一光栅具有耦入光栅矢量，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量，其特征在于，所述第一光栅和所 述第二光栅各自的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形，
    其中，所述第二光栅是二维表面浮雕光栅，该二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
    多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
    多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
  24. 根据权利要求23所述的用于AR设备的光波导装置，其中，所述第一光栅具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，所述第二光栅具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
    P0＝Py，并且s＝k*Px
    其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
  25. 根据权利要求24所述的用于AR设备的光波导装置，其中，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
  26. 根据权利要求23至25中任一项所述的用于AR设备的光波导装置，其中，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
  27. 根据权利要求23至26中任一项所述的用于AR设备的光波导装 置，其中，所述三阶柱体阵列结构的柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
  28. 根据权利要求23至27中任一项所述的用于AR设备的光波导装置，其中，所述三阶柱体阵列结构的三阶柱体的表面至少在三个方向具有高度下降的梯度，其中，第一个方向是第二光栅耦入光线的传输方向，第二个方向是第二光栅左侧转折光线的传输方向，第三个方向是第二光栅右侧转折光线的传输方向。
  29. 根据权利要求23至28中任一项所述的用于AR设备的光波导装置，其中，所述第二柱体设置成相对于所述第一柱体朝向所述第一光栅所在的方向偏置。
  30. 根据权利要求29所述的用于AR设备的光波导装置，其中，所述第二柱体的底面关于所述第一柱体的底面相切，并且相切点位于所述第二柱体的偏置方向上。
  31. 根据权利要求23至30中任一项所述的用于AR设备的光波导装置，其中，所述第二柱体的底面是按照所述第一柱体的底面以预设的缩小率进行等比例缩小。
  32. 根据权利要求31所述的用于AR设备的光波导装置，其中，所述缩小率的范围是0.45-0.65。
  33. 根据权利要求31所述的用于AR设备的光波导装置，其中，在所述第二光栅单元阵列的第一维度方向和第二维度方向上组成的二维平面内，所述第二柱体在该二维平面内的投影至少在三个方向小于与其相对应的第一柱体在该二维平面内的投影。
  34. 根据权利要求23至33中任一项所述的用于AR设备的光波导装置，其中，所述第一高度的范围为30nm-65nm，并且所述第二高度与所述第一高度具有基本上相当的高度。
  35. 根据权利要求23至34中任一项所述的用于AR设备的光波导装置，其中，所述第二光栅单元阵列设置成从所述耦出区的外表面向外凸出或者向内凹进，并且所述第一光栅单元阵列设置成从所述耦入区的外表面向外凸出或者向内凹进。
  36. 根据权利要求23至35中任一项所述的用于AR设备的光波导装置，其中，所述第一光栅包括闪耀光栅、倾斜光栅和二元光栅。
  37. 根据权利要求23至36中任一项所述的用于AR设备的光波导装置，其中，所述光波导基底的厚度为0.3mm-2.5mm，折射率为1.4-2.2。
  38. 一种AR设备，其特征在于，所述AR设备包括：
    一个或多个如权利要求23至37中任一项所述的用于AR设备的光波导装置；以及
    投像装置，其布置在所述光波导装置的入光侧用于发送出图像光线，使其入射至所述光波导装置的耦入区。
  39. 一种用于AR设备的光波导装置的制造方法，其特征在于，所述制造方法包括步骤：
    提供光波导基底；
    设置具有第一光栅的耦入区，所述第一光栅具有耦入光栅矢量并使得入射光线耦入所述光波导基底内；以及
    设置具有第二光栅的耦出区，所述第二光栅具有彼此交叉的第一耦出光栅矢量和第二耦出光栅矢量并且将来自所述光波导基底的光线二维扩展后耦出，其中所述第二光栅的光栅单元阵列与所述第一光栅的光栅单元阵列在一个维度方向上基本上平行且周期相同，所述第一耦出光栅矢量和所述第二耦出光栅矢量相对于所述耦入光栅矢量形成对称而与所述耦入光栅矢量一起组成等腰三角形，
    其中，将所述第二光栅构造成二维表面浮雕光栅，该二维表面浮雕光栅具有三阶柱体阵列结构，其包括：
    多个第一柱体，其被排列形成所述第二光栅单元阵列，其中每一个从所述耦出区的外表面向外凸出，并且在垂直于所述外表面的方向上具有第一高度；以及
    多个第二柱体，其中每一个布置在相对应的第一柱体的顶部，并且在垂直于所述外表面的方向上具有第二高度，所述第二柱体的底面被包含在所述第一柱体的顶面内，所述第二柱体的底面面积小于所述第一柱体的底面面积。
  40. 根据权利要求39所述的用于AR设备的光波导装置的制造方法，其中，将所述第一光栅构造成具有在与其光栅槽线方向相垂直的第一维度方向上周期性排布的第一光栅单元阵列，并且将所述第二光栅构造成具有在所述第一维度方向和与其相垂直的第二维度方向上周期性排布的第二光栅单元阵列，所述第一光栅单元阵列和所述第二光栅单元阵列的周期符合以下关系式：
    P0＝Py，并且s＝k*Px
    其中，P0是所述第一光栅单元阵列在所述第一维度方向上的周期，Px和Py分别是所述第二光栅单元阵列在所述第一维度方向和所述第二维度方向上的周期，s是所述第二光栅单元阵列中的相邻两行之间在所述第一维度方向上的偏移量，k是取值范围为0.45-0.55的系数。
  41. 根据权利要求40所述的用于AR设备的光波导装置的制造方法，其中，所述第一光栅单元阵列的周期P0的大小范围为250nm-500nm，所述第二光栅单元阵列的周期Py与周期Px之间比值为0.7-1.2。
  42. 根据权利要求39至41中任一项所述的用于AR设备的光波导装置的制造方法，其中，所述第二光栅还具有衍生光栅矢量，所述衍生光栅矢量的量值与所述耦入光栅矢量的量值之间比值为0.45-0.55。
  43. 根据权利要求39至42中任一项所述的用于AR设备的光波导装置的制造方法，其中，所述三阶柱体阵列结构的柱体的截面形状包括圆形、椭圆形、多边形及其任意组合。
  44. 根据权利要求43所述的用于AR设备的光波导装置的制造方法，其中，所述三阶柱体阵列结构的三阶柱体的表面至少在三个方向具有高度下降的梯度，其中，第一个方向是第二光栅耦入光线的传输方向，第二个方向是第二光栅左侧转折光线的传输方向，第三个方向是第二光栅右侧转折光线的传输方向。
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