WO2024077907A1 - 显示设备、虚拟图像显示方法和显示设备的制造方法 - Google Patents

显示设备、虚拟图像显示方法和显示设备的制造方法 Download PDF

Info

Publication number
WO2024077907A1
WO2024077907A1 PCT/CN2023/087969 CN2023087969W WO2024077907A1 WO 2024077907 A1 WO2024077907 A1 WO 2024077907A1 CN 2023087969 W CN2023087969 W CN 2023087969W WO 2024077907 A1 WO2024077907 A1 WO 2024077907A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
input
waveguide substrate
display device
sub1
Prior art date
Application number
PCT/CN2023/087969
Other languages
English (en)
French (fr)
Inventor
朱良富
朱以胜
塔帕尼卡列沃·利沃拉
Original Assignee
深圳市光途显示科技有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 深圳市光途显示科技有限公司 filed Critical 深圳市光途显示科技有限公司
Publication of WO2024077907A1 publication Critical patent/WO2024077907A1/zh

Links

Classifications

    • 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
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1086—Beam splitting or combining systems operating by diffraction only
    • 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
    • G02B27/42—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect
    • G02B27/4205—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
    • 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
    • G02B27/0081—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means for altering, e.g. enlarging, the entrance or exit pupil
    • 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
    • G02B27/017—Head mounted
    • G02B27/0172—Head mounted characterised by optical features
    • 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
    • G02B27/10—Beam splitting or combining systems
    • G02B27/106—Beam splitting or combining systems for splitting or combining a plurality of identical beams or images, e.g. image replication
    • 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
    • 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
    • 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
    • G02B2027/0123—Head-up displays characterised by optical features comprising devices increasing the field of view
    • G02B2027/0125—Field-of-view increase by wavefront division
    • 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

Definitions

  • the present invention relates to the field of virtual display technology, and in particular to a display device, a virtual image display method and a method for manufacturing the display device.
  • FIG. 1 is a known display device
  • a known image display device includes a light engine ENG1 and a diffraction beam expansion device EPEO.
  • the display device displays a virtual image by diffraction expansion of the image light beam provided by the light engine ENG1.
  • the diffraction beam expansion device EPEO provides an enlarged observable area (hereinafter referred to as an eye box) BOX1 to observe the virtual image.
  • the diffraction beam expansion device EPEO includes a waveguide substrate SUB0, an input element DOE1, and an output element DOE3.
  • the light engine ENG1 forms input light IN1.
  • the input light includes input light beams (B0P1, B0P2) transmitted in different directions corresponding to different image points (P1, P2) on the input image (IMG0).
  • the beam expander EPEO forms an output beam by diffracting and expanding the input light IN1.
  • the diffraction beam expander EPEO forms an output beam B3P1 by diffracting and expanding the input light beam B0P1.
  • the diffraction beam expander EPEO forms an output beam B3P2 by diffracting and expanding the input light beam B0P2.
  • the input element DOE1 forms the guided light (B1P1, B1P2) by diffracting the input light IN1.
  • the guided light (B1P1, B1P2) is transmitted in the waveguide substrate SUB0.
  • the output element DOE3 forms the output light beam (B3P1, B3P2) by diffracting the guided light (B1P1, B1P2) out of the waveguide substrate SUB0.
  • the output light beam (B3P1, B3P2) enters the eyes of the observer, the observer can see the displayed virtual image.
  • the set of output light beams corresponding to different image points together constitute the output light.
  • the output light may show uneven spatial or angular distribution.
  • the output light beam B3P1 may become weaker as the distance from the input element DOE1 increases.
  • the energy of the output light beam B3P1 corresponding to the image pixel P1 output from a fixed position of the output unit DOE3 may be weaker than the energy of the output light beam B3P2 corresponding to the image pixel P2 output from the same position, even if the input light beams (B0P1, B0P2) corresponding to the output light beams have the same energy.
  • the present invention provides a display device, a virtual image display method and a method for manufacturing the display device.
  • the present invention provides a display device (500), comprising:
  • a beam expander stack for expanding the input light (IN1) by diffraction to form an output light (OUT1), wherein the output light (OUT1) comprises a series of output light beams (B3aP1, B3aP2, B3bP1, B3bP2) representing the input image (IMG0);
  • the beam expander stack (STC1) comprises a first beam expander (EPE1) and a second beam expander (EPE2);
  • the first beam expansion device (EPE1) comprises a first diffraction element combination (GRP1) for controlling the first a propagation direction of an output light beam (B3aP1, B3aP2);
  • the second beam expansion device comprises a second diffraction element combination (GRP2) for controlling the propagation direction of the second output light beam (B3bP1, B3bP2),
  • the first beam expansion device (EPE1) comprises a first input element (DOE1a) for diffracting the input light (IN1) into a waveguide substrate (SUB1) of the first beam expansion device (EPE1);
  • the first beam expanding device (EPE1) is configured to allow part of the input light (IN1) to be transmitted through the first beam expanding device (EPE1) to the second beam expanding device (EPE2);
  • the second beam expander (EPE2) comprises a second input element (DOE1b) for diffracting a portion of the input light (IN1) transmitted through the first beam expander and inputting it into a waveguide substrate (SUB2) of the second beam expander (EPE2);
  • the grating period (d1a, d2a, d3a) of each diffraction element (DOE1a, DOE2a, DOE3a) in the first diffraction element combination (GRP1) is equal to the grating period (d1b, d2b, d3b) of each corresponding diffraction element (DOE1b, DOE2b, DOE3b) in the second diffraction element combination (GRP2).
  • the present invention further provides a virtual image display method, which is applied to a display device (500), wherein the display device is a display device (500) according to any one of the above items, and the display method comprises:
  • input light (IN1), the input light comprising light beams (B0P1, B0P2) corresponding to different image points (P1, P2) on an input image (IMG0);
  • the beam expander stack (STC1) is used to diffract and expand the input light (IN1) to form output light (OUT1).
  • the present invention provides a method for manufacturing a display device, the method being used to manufacture a display device (500) as described in any one of the above items, the method comprising:
  • the first input element (DOE1a) and the second input element (DOE1b) are manufactured using the same imprint master (TOOL1).
  • the display device provided by the present invention includes a light engine for forming input light.
  • the input light includes a series of input light beams corresponding to input image pixels.
  • the propagation direction of each input light beam depends on the position of the image pixel corresponding to it, and the intensity of each input light beam corresponds to the brightness of the corresponding image pixel.
  • the display device includes a stack formed by overlapping a plurality of beam expanders, which are used to receive input light and form output light.
  • the output light includes a series of output light beams corresponding to the input image points.
  • the beam expander stack expands the input light beam by diffraction to form the output light beam.
  • the beam expander stack includes a first beam expander and a second beam expander, the first beam expander includes a first input element, the first input element diffracts input light into the waveguide substrate of the first beam expander.
  • the first input element allows a portion of the input light to be transmitted through the first beam expander to the second beam expander.
  • the second beam expander includes a second input element, the second input element diffracts the input light transmitted through the first beam expander into the waveguide substrate of the second beam expander.
  • the first beam expander includes a first output element, which forms a first output beam by diffracting the guided light transmitted in the waveguide substrate of the first beam expander.
  • the second beam expander includes a second output element, which forms a second output beam by diffracting the guided light transmitted in the waveguide substrate of the second beam expander. Output beam.
  • the first output beam output by the first output element can pass through the second beam expansion device and be transmitted to the observer's eyes.
  • the total output beam is composed of the first output beam or the second output beam.
  • FIG1 is a conventional display device
  • FIG2 is a side view of a display device including a stack of diffractive beam expansion devices according to an embodiment of the present application
  • FIG3a is a three-dimensional schematic diagram of a display device including a stack of diffractive beam expansion devices according to an embodiment of the present application;
  • FIG3 b is a three-dimensional schematic diagram of a guided light transmission in the second diffractive beam expansion device shown in FIG3 a ;
  • FIG4 a is a side view of a display device proposed in an embodiment of the present application, wherein the thickness of the waveguide substrate of the first beam expander is different from the thickness of the waveguide substrate of the second beam expander.
  • FIG4b is a side view of a display device proposed in an embodiment of the present application, wherein the waveguide substrate of the first beam expansion device is composed of two layers of different materials;
  • FIG5a is a curve showing the relationship between the average brightness in the eye box of a display device and the ratio of the thickness of two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device;
  • FIG5 b is a diagram showing the relationship between the standard deviation of the angular distribution difference of image brightness in an eye box of a display device and the ratio of the thickness of two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device;
  • FIG5c is a diagram showing the relationship between the standard deviation of the image brightness position distribution difference in the eye box of a display device and the ratio of the thickness of the two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device;
  • FIG6a is a schematic diagram of the dimensions of a first beam expanding device included in a display device proposed in an embodiment of the present application
  • FIG6 b is a schematic diagram of the dimensions of a second beam expanding device included in a display device provided in an embodiment of the present application;
  • FIG6 c is a three-dimensional schematic diagram of a first beam expansion device processed by using an imprint master
  • FIG6d is a three-dimensional schematic diagram of a second beam expander fabricated using the same imprint master as in FIG6c;
  • 7a to 7e are three-dimensional schematic diagrams of a light engine generating an input light beam
  • FIG7 f is a three-dimensional schematic diagram of observing a displayed virtual image
  • FIG7g is a schematic diagram of the angular width of a displayed virtual image
  • FIG. 7h is a schematic diagram showing the angle height of a displayed virtual image.
  • Fig. 2 is a side view of a display device including a diffractive beam expander stack according to an embodiment of the present application.
  • the display device 500 includes a light engine ENG1 and a beam expander stack STC1 consisting of a first beam expander EPE1 and a second beam expander EPE2.
  • the light engine ENG1 can provide input light IN1, which includes input light beams B0P1, B0P2 corresponding to the first image pixel P1 and the second image pixel P2 in the image IMG0.
  • the display device 500 can also receive the input light IN1 generated by the light engine ENG1.
  • the stack STC1 may include two or more beam expanders.
  • the stack STC1 includes at least one first beam expander EPE1 and one second beam expander EPE2.
  • the beam expander stack STC1 consisting of the first beam expander EPE1 and the second beam expander EPE2 may provide an output light OUT1.
  • the first beam expander EPE1 and the second beam expander EPE2 may be operated so that the output light OUT1 includes output light beams B3aP1, B3aP2, B3bP1, B3bP2 corresponding to the first image pixel P1 and the second image pixel P2.
  • FIG3a is a three-dimensional schematic diagram of a display device including a stack of diffractive beam expanders proposed in an embodiment of the present application.
  • the output light OUT1 enters the eye EYE1 of the observer, the observer can see the displayed virtual image VIMG1.
  • the display device 500 has an eye box BOX1, which represents the range where the observer can place his eye EYE1, and the complete virtual image displayed can be seen in this range.
  • the first beam expansion device EPE1 includes a first waveguide substrate SUB1, and the first waveguide substrate SUB1 further includes several diffraction elements for controlling the propagation direction of light.
  • the first waveguide substrate SUB1 may include a first input element DOE1a, a first beam expansion element DOE2a and a first output element DOE3a.
  • the first input element DOE1a may diffract the input light IN1 into the first waveguide substrate SUB1 of the first beam expansion device EPE1 to form a first transmission light B1a transmitted in the first waveguide substrate SUB1.
  • the first beam expansion element DOE2a forms a second transmission light B2a by diffracting the first transmission light B1a.
  • the first output element DOE3a forms an output light OUT1 by diffracting the second transmission light B2a out of the first waveguide substrate SUB1.
  • the output light OUT1 diffracted and output by the first output element DOE3a may include an output light beam, such as B3aP1, B3aP2, as shown in FIG. 7f, which is a three-dimensional schematic diagram of observing a displayed virtual image.
  • the first beam expander EPE1 may include a first diffraction element combination GRP1 consisting of a first input element DOE1a of a diffraction element, a first beam expander DOE2a and a first output element DOE3a, as shown in FIG6a, which is a schematic diagram of the dimensions of a first beam expander included in a display device proposed in an embodiment of the present application.
  • the first diffraction element combination GRP1 is used to control the transmission direction of the output light OUT1.
  • a portion of the input light IN1 can pass through the first beam expander EPE1 and be transmitted to the second input element DOE1b of the second beam expander EPE2.
  • This portion of the input light IN1 that passes through the first beam expander EPE1 and is transmitted to the second input element DOE1b can be called the transmitted input light, denoted as IN2.
  • the second beam expansion device EPE2 includes a second waveguide substrate SUB2, and the second waveguide substrate SUB2 may further include a second input element DOE1b, a second beam expansion element DOE2b and a second output element DOE3b.
  • the second input element DOE1b may form a third transmission light B1b by diffracting the transmitted input light IN2 into the second waveguide substrate SUB2.
  • the second beam expansion element DOE2b forms a fourth transmission light B2b by diffracting the third transmission light B1b, as shown in FIG3b, which is a three-dimensional schematic diagram of a transmission light in the second diffraction beam expansion device shown in FIG3a.
  • the second output element DOE3b forms an output light OUT1 by diffracting the fourth transmission light B2b out of the second waveguide substrate SUB2.
  • the output light OUT1 diffracted by the second output element DOE3b may include output light beams, such as B3bP1, B3bP2, as shown in FIG7f.
  • the second beam expansion device EPE2 may include a second diffraction element combination GRP2 composed of diffraction elements DOE1b, DOE2b and DOE3b, as shown in FIG6b, which is a schematic diagram of the dimensions of a second beam expansion device included in a display device proposed in an embodiment of the present application.
  • the second diffraction element combination GRP2 is used to control the transmission direction of the output light OUT1.
  • the output light diffracted by the first output element DOE3a of the first beam expander EPE1 can pass through the second output element DOE3b of the second beam expander EPE2 and be transmitted to the eyes of the observer.
  • the overall output light of the display device 500 can be regarded as a combination of the output light of the first beam expander EPE1 and the output light of the second beam expander EPE2.
  • SX, SY and SZ represent orthogonal directions.
  • the plane where the first waveguide substrate SUB1 is located may be in the plane defined by SX and SY.
  • the first waveguide substrate SUB1 of the first beam expander EPE1 has two mutually parallel main planes SRF1a and SRF2a, as shown in FIG4a, which is a side view of a display device proposed in an embodiment of the present application, wherein the thickness of the first beam expander waveguide substrate is different from the thickness of the second beam expander waveguide substrate.
  • the second waveguide substrate SUB2 of the second beam expander EPE2 has two mutually parallel main planes SRF1b and SRF2b.
  • LC1 and LC2 represent a lower coupling efficiency, and HC1 and HC2 represent a higher coupling efficiency.
  • the input light beams B0P1 and B0P2 corresponding to different P1 and P2 image points on the image are transmitted in different directions.
  • the first input element DOE1a may couple the input light beams B0P1 and B0P2 into the first waveguide substrate SUB1 with different diffraction efficiencies.
  • the first input element DOE1a may couple the input light beam B0P1 into the first waveguide substrate SUB1 with a lower coupling efficiency LC1
  • the first input element DOE1a may couple the input light beam B0P2 into the first waveguide substrate SUB1 with a higher coupling efficiency HC1.
  • the second input element DOE1b of the second beam expansion device EPE2 may couple the input light beams B0P1 and B0P2 into the second waveguide substrate SUB2 with different diffraction efficiencies.
  • the second input element DOE1b may couple the input light beam B0P1 into the second waveguide substrate SUB2 with a higher coupling efficiency HC2, while the first input element DOE1a may couple the input light beam B0P2 into the second waveguide substrate SUB2 with a lower coupling efficiency LC2.
  • the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ) represents the efficiency of the first beam expander EPE1 coupling the input beam and forming the output beam.
  • the efficiency function is a function of the position (x, y) of the first output element DOE3a and a function of the output beam propagation direction ( ⁇ , ⁇ ).
  • the position can be specifically represented by, for example, a position coordinate value (x, y).
  • the beam propagation direction can be specifically represented by an angle ( ⁇ , ⁇ ).
  • the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) represents the efficiency of the second beam expansion device EPE2 in coupling the input light beam and forming the output light beam.
  • This efficiency function is a function of the position (x, y) of the second output element DOE3b and also a function of the propagation direction ( ⁇ , ⁇ ) of the output light beam.
  • the first waveguide substrate SUB1 may have a first thickness tSUB1.
  • the second waveguide substrate SUB2 may have a second thickness tSUB2.
  • the first input element DOE1a may have a first refractive index n1
  • the second input element DOE1b may have a second refractive index n2, as shown in FIG. 4a and FIG. 4b, FIG. 4b is a side view of a display device proposed in an embodiment of the present application, wherein the waveguide substrate of the first beam expansion device is composed of two different material layers.
  • the refractive index of the diffraction element refers to the refractive index of the micro-diffraction structure of the diffraction element.
  • the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b and/or the first thickness tSUB1 of the first waveguide substrate SUB1 of the first beam expander EPE1 and the second thickness tSUB2 of the second waveguide substrate SUB2 of the second beam expander EPE2 may be selected so that the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) is different from the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) may be different from the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ) by selecting the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b.
  • the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) may be different from the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ) by selecting the first thickness tSUB1 of the first waveguide substrate SUB1 and the second thickness tSUB2 of the second waveguide substrate SUB2.
  • the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) can be made different from the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ) by selecting the values of the first refractive index n1 and the second refractive index n2, and selecting the values of the first thickness tSUB1 and the second thickness tSUB2.
  • the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b and/or the first thickness tSUB1 of the first waveguide substrate SUB1 of the first beam expander EPE1 and the thickness tSUB2 of the second waveguide substrate SUB2 of the second beam expander EPE2 may be selected so that the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) at least partially compensates for the uneven position and/or angle distribution of the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b may be selected so that the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) at least partially compensates for the uneven position and/or angle distribution of the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the first thickness tSUB1 of the first waveguide substrate SUB1 and the second thickness tSUB2 of the second waveguide substrate SUB2 can be selected so that the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) at least partially compensates for the uneven position and/or angle distribution of the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the first refractive index n1 and the second refractive index n2 can be selected, and the first thickness tSUB1 and the second thickness tSUB2 of the second waveguide substrate SUB2 can be selected.
  • the values of the second thickness tSUB1 and the second thickness tSUB2 are such that the second coupling efficiency function ⁇ EPE2(x, y, ⁇ , ⁇ ) at least partially compensates for the uneven position and/or angle distribution of the first coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b and/or the first thickness tSUB1 of the first waveguide substrate SUB1 of the first beam expander EPE1 and the thickness tSUB2 of the second waveguide substrate SUB2 of the second beam expander EPE2 may be selected so that the output light OUT1 of the second beam expander at least partially compensates for the uneven distribution of the output light OUT1 of the first beam expander.
  • the first refractive index n1 of the first input element DOE1a and the second refractive index n2 of the second input element DOE1b may be selected so that the output light OUT1 of the second beam expander at least partially compensates for the uneven distribution of the output light OUT1 of the first beam expander.
  • the first thickness tSUB1 of the first waveguide substrate SUB1 and the second thickness tSUB2 of the second waveguide substrate SUB2 may be selected so that the output light OUT1 of the second beam expander at least partially compensates for the uneven distribution of the output light OUT1 of the first beam expander.
  • the output light OUT1 of the second beam expanding device can at least partially compensate for the uneven distribution of the output light OUT1 of the first beam expanding device.
  • the beam expander stack STC1 can be configured to at least partially compensate for the difference in beam energy coupled out from an area (NEAR1) close to the first input element DOE1a and an area (FAR1) far from the first input element DOE1a.
  • the display device 500 includes a light engine ENG1 and a beam expander stack STC1 consisting of different first beam expanders EPE1 and second beam expanders EPE2.
  • the light engine ENG1 may include a display screen DISP1 and a collimating lens group LNS1.
  • the display screen DISP1 may be configured to display an input image IMG0.
  • the display screen DISP1 may also be referred to as a microdisplay.
  • the display screen DISP1 may also be referred to as a spatial light modulator.
  • the input image IMG0 may also be referred to as an initial image.
  • the input image IMG0 may include a series of image pixels, such as P1 and P2.
  • the light engine ENG1 may include a collimating lens group LNS1, which is used to collimate the image pixels, such as light emitted by P1 and P2, to form input light.
  • the light engine ENG1 forms input light IN1, which includes a plurality of input light beams corresponding to different image pixels on the input image IMG0, such as P1 and P2.
  • the light engine ENG1 can be optically coupled to the first input element DOE1a and the second input element DOE1b.
  • the beam expander stack STC1 composed of the first beam expander EPE1 and the second beam expander EPE2 can carry the virtual image obtained from the light engine ENG1 and transmit it to the observer's eye EYE1.
  • the first beam expander EPE1 and the second beam expander EPE2 can expand the viewable pupil, thereby expanding the eye box BOX1.
  • the first beam expansion device EPE1 may include a first input element DOE1a, a first beam expansion element DOE2a, and a first output element DOE3a in the diffraction element.
  • the first input element DOE1a forms a first transmission light B1a by diffracting the input light IN1.
  • the first beam expansion element DOE2a forms a second transmission light B2a by diffracting the first transmission light B1a.
  • the first output element DOE3a forms an output light beam (B3aP1, B3aP2) by diffracting the second transmission light B2a.
  • a portion of the input light beam IN1, the transmitted input light IN2, may be transmitted through the first input element DOE1a and transmitted to the second input element DOE1b.
  • the transmitted input light IN2 may be transmitted substantially along a direction such as SZ.
  • the second beam expansion device EPE1 may include a second input element DOE1b, a second beam expansion element DOE2b, and a second output element DOE3b in the diffraction element.
  • the second input element DOE1b forms a third transmission light B1b by diffracting the transmitted part of the input light IN2.
  • the second beam expansion element DOE2b forms a fourth transmission light B2b by diffracting the third transmission light B1b.
  • the second output element DOE3b forms an output light beam (B3bP1, B3bP2) by diffracting the fourth transmission light B2b.
  • the first beam expander EPE1 and the second beam expander EPE2 can diffract and expand the light.
  • the width wOUT1 of the output light beam in the output light OUT1 can be much larger than the width wIN1 of the input light beam in the input light IN1.
  • the observer can see the virtual image VIMG1.
  • the displayed virtual image VIMG1 can represent the input image IMG0.
  • the first output light beam generated by the first beam expansion device EPE1 can pass through the second beam expansion device EPE2 and be transmitted to the eyes of the observer.
  • the overall output light OUT1 can be regarded as a combination of the first output light beam and the second output light beam.
  • the guided light is confined within the waveguide substrate by total internal reflection (TIR).
  • TIR total internal reflection
  • the guided light mentioned here has the same meaning as the waveguide light.
  • the thickness tSUB2 of the second waveguide substrate SUB2 may be different from the thickness tSUB1 of the first waveguide substrate SUB1.
  • the refractive index n2 of the second input element DOE1b on the second waveguide substrate SUB2 may also be different from the refractive index n1 of the first input element DOE1a on the first waveguide substrate SUB1.
  • the difference between the thickness of the first waveguide substrate and the thickness of the second waveguide substrate and the difference between the refractive index of the first input element and the refractive index of the second input element may at least partially compensate for the non-uniformity of the coupling efficiency function ⁇ EPE1(x, y, ⁇ , ⁇ ).
  • the grating period d1a of the first input element DOE1a may be equal to the grating period d1b of the second input element DOE1b.
  • the display device (500) may include:
  • a light engine for forming an input light (IN1) comprising a series of input light beams (B0P1, B0P2) representing an input image (IMG0),
  • a beam expander stack for expanding the input light (IN1) by diffraction to form an output light (OUT1), the output light (OUT1) comprising a series of output light beams (B3aP1, B3aP2, B3bP1, B3bP2) representing the input image (IMG0),
  • the beam expander stack (STC1) comprises a first beam expander (EPE1) and a second beam expander (EPE2);
  • the first beam expansion device (EPE1) comprises a first input element (DOE1a) for diffracting input light (IN1) into a first waveguide substrate (SUB1) of the first beam expansion device (EPE1),
  • the first beam expanding device (EPE1) is configured to allow a portion (IN2) of the input light (IN1) to be transmitted through the first beam expanding device (EPE1) to the second beam expanding device (EPE2);
  • the second beam expander (EPE2) comprises a second input element (DOE1b) for diffracting a portion (IN2) of the input light (IN1) that passes through the first beam expander and inputting it into a waveguide substrate (SUB2) of the second beam expander (EPE2);
  • the grating period (d1a) of the first input element (DOE1a) is equal to the grating period (d1b) of the second input element (DOE1b).
  • the display device (500) may include:
  • a beam expander stack comprising a first beam expander (EPE1) and a second beam expander (EPE2);
  • the grating period (d1a, d2a, d3a) of each diffraction element (DOE1a, DOE2a, DOE3a) on the first beam expanding device (EPE1) is equal to the grating period (d1b, d2b, d3b) of each corresponding diffraction element (DOE1b, DOE2b, DOE3b) on the second beam expanding device (EPE2).
  • the display device (500) may include:
  • a beam expander stack for expanding the input light (IN1) by diffraction to form an output light (OUT1), the output light (OUT1) comprising a series of output light beams (B3aP1, B3aP2, B3bP1, B3bP2) representing the input image (IMG0);
  • the beam expander stack (STC1) comprises a first beam expander (EPE1) and a second beam expander (EPE2).
  • the first beam expanding device (EPE1) includes a first diffraction element combination (GRP1), and the first diffraction element combination (GRP1) includes a first input element DOE1a, a first beam expanding element DOE2a, and a first output element DOE3a, which are used to control the propagation direction of the output light beam (B3aP1, B3aP2).
  • the second beam expansion device (EPE2) includes a second diffraction element combination (GRP2), and the second diffraction element combination (GRP2) includes a second input element DOE1b, a second beam expansion element DOE2b, and a second output element DOE3b, which are used to control the propagation direction of the output light beam (B3bP1, B3bP2).
  • the first beam expansion device (EPE1) comprises a first input element (DOE1a) for diffracting input light (IN1) and inputting it into a waveguide substrate (SUB1) of the first beam expansion device (EPE1).
  • the first beam expanding device (EPE1) is arranged so that a portion (IN2) of the input light (IN1) is transmitted through the first beam expanding device (EPE1) to the second beam expanding device (EPE2).
  • the second beam expander (EPE2) comprises a second input element (DOE1b) for diffracting a portion (IN2) of the input light (IN1) that passes through the first beam expander and inputting it into a waveguide substrate (SUB2) of the second beam expander (EPE2);
  • the grating period (d1a, d2a, d3a) of each diffraction element (DOE1a, DOE2a, DOE3a) in the first diffraction element combination (GRP1) is equal to the grating period (d1b, d2b, d3b) of each corresponding diffraction element (DOE1b, DOE2b, DOE3b) in the second diffraction element combination (GRP2).
  • the equal grating periods (d1a, d1b) can simplify the manufacture of the display device (500) because the first expansion
  • the beam expansion device EPE1 and the second beam expansion device EPE2 can be manufactured using the same imprint master, as shown in Figures 6c and 6d
  • Figure 6c is a three-dimensional schematic diagram of using an imprint master to process a first beam expansion device
  • Figure 6d is a three-dimensional schematic diagram of using the same imprint master as Figure 6c to process a second beam expansion device.
  • the equal grating periods (d1a, d1b) can improve the uniformity of the displayed virtual image VIMG1, while reducing or eliminating the risk of mismatch in propagation direction between the output light beam of the first beam expander EPE1 and the output light beam of the second beam expander EPE2.
  • the first waveguide substrate SUB1 and/or the second waveguide substrate SUB2 may include one or more layers of material (S11, S12, S21, S22).
  • the first waveguide substrate SUB1 includes one or more layers of material (S11, S12, S21, S22)
  • the second waveguide substrate SUB2 includes one or more layers of material (S11, S12, S21, S22)
  • both the first waveguide substrate SUB1 and the second waveguide substrate SUB2 include one or more layers of material (S11, S12, S21, S22).
  • the material forming the first waveguide substrate SUB1 and the material forming the second waveguide substrate SUB2 may be the same or different.
  • the material forming the first waveguide substrate SUB1 and the material forming the second waveguide substrate SUB2 may be different.
  • the first waveguide substrate SUB1 includes a first material S11 and the second waveguide substrate SUB2 includes a second material S12.
  • the material forming the first waveguide substrate SUB1 and the material forming the second waveguide substrate SUB2 may be completely different.
  • the first waveguide substrate SUB1 includes a first material S11 and a second material S12
  • the second waveguide substrate SUB2 includes a third material S21 and a fourth material S22. It is understandable that the material forming the first waveguide substrate SUB1 and the material forming the second waveguide substrate SUB2 may also be partially different.
  • the first waveguide substrate SUB1 includes a first material S11 and a second material S12
  • the second waveguide substrate SUB2 includes a second material S12 and a fourth material S22.
  • the first waveguide substrate SUB1 is formed of multiple layers of material
  • the second waveguide substrate SUB2 is formed of a single layer of material.
  • the first waveguide substrate SUB1 is formed of a single layer of material
  • the second waveguide substrate SUB2 is formed of multiple layers of material.
  • At least one of the first waveguide substrate SUB1 of the first beam expander EPE1 and the second waveguide substrate SUB2 of the second beam expander EPE2 includes two or more layers of material (S11, S12, S21, S22). Using two or more layers of material can provide additional degrees of freedom in selecting the material refractive index (n11, n1, n21, n2). The additional degrees of freedom can be used to provide more appropriate coupling efficiency functions, such as ⁇ EPE1(x, y, ⁇ , ⁇ ) and ⁇ EPE2(x, y, ⁇ , ⁇ ).
  • the multilayer materials are not limited to the first material S11, the second material S12, the third material S21 and the fourth material S22 illustrated as examples, and can be a combination of more than four materials.
  • the specific settings are not specifically limited here and can be set according to actual conditions.
  • the first waveguide substrate SUB1 may include two or more layers of material.
  • the second waveguide substrate SUB2 may also include two or more layers of material.
  • the material layers here may be transparent to achieve the conduction of light beams.
  • the first transparent substrate S11 may be coated or spin-coated with a layer of transparent material to form a first transparent film layer S12.
  • the first input element DOE1a may be constructed on the first transparent film layer S12.
  • the first transparent substrate S11 may have a third refractive index n11.
  • the first transparent film layer S12 may have a first refractive index n1.
  • the second transparent substrate S21 may be coated or spin-coated with a layer of transparent material to form a second transparent film layer S22.
  • the second input element DOE1b may be constructed on the second transparent film layer S22.
  • the second transparent substrate S21 may have a fourth refractive index n21.
  • the second transparent film layer S12 may have a second refractive index n2.
  • the display device 500 has an eye box BOX1 , as shown in FIG. 2 , and the eye box BOX1 represents a space where an observer can place an eye EYE1 and see the displayed virtual image VIMG1 .
  • Figure 5a is a curve showing the relationship between the average brightness in the eye box of a display device and the thickness ratio of the two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device.
  • Figure 5a shows a curve showing the relationship between the average image intensity in an eye box BOX1 and the thickness ratio tSUB2/tSUB1.
  • the n2 refractive index corresponding to the three curves is 1.9.
  • the grating period of each diffraction element on the first beam expander (EPE1) is equal to the grating period of each corresponding diffraction element on the second beam expander (EPE2).
  • the grating period of the first input element DOE1a in each diffraction element on the first beam expander (EPE1) is d1a
  • the grating period of the first beam expander DOE2a is d2a
  • the grating period of the first output element DOE3a is d3a
  • the grating period of the second input element DOE1b in each diffraction element on the second beam expander (EPE2) is d1b
  • the grating period of the second beam expander DOE2b is d2b
  • the grating period of the second output element DOE3b is d3b.
  • the grating period d1a of the first input element DOE1a is equal to the grating period d1b of the second input element DOE1b
  • the grating period d2a of the first beam expander DOE2a is equal to the grating period d2b of the second beam expander DOE2b
  • the grating period d3a of the first output element DOE3a is equal to the grating period d3b of the second output element DOE3b.
  • the input image IMG0 is uniform, that is, all image points of the input image IMG0 have equal brightness.
  • Ref01 is the average intensity in the eye box BOX1 when the display device includes only one beam expander EPE2.
  • the case of point OP1 is significantly higher (+24%) than the average brightness of the comparative example Ref01.
  • the symbol a.u. represents an arbitrary unit.
  • the display device 500 may be configured to display the virtual image VIMG1 with a sufficient degree of uniformity. Position uniformity and/or angular uniformity may be optimized. The display device 500 may be configured to provide sufficient position display uniformity; the display device 500 may also be configured to provide sufficient angular display uniformity.
  • the display device 500 can provide a substantially uniform directional intensity distribution in different directions within the eye box BOX1, and the display device 500 can also provide a substantially uniform positional intensity distribution at different positions within the eye box BOX1.
  • Uniform directional distribution means that when the input image is a uniform image, the light beams transmitted in different directions have equal intensity.
  • Uniform directional distribution means that different image points P1 and P2 on the virtual image VIMG1 seen by the eye EYE1 located in the eye box BOX1 have the same brightness.
  • the degree of uniform directional distribution can be measured by the standard deviation of the difference in intensity at different angles. A lower standard deviation indicates higher uniformity.
  • Figure 5b shows the relationship between the standard deviation of the angular distribution difference of the image brightness in the eye box of a display device and the ratio of the thickness of the two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device.
  • the standard deviation in Figure 5b represents the intensity difference between the output beams in different propagation directions.
  • the input image IMG0 is uniform, that is, all image points of the input image IMG0 have equal brightness.
  • Ref02 shows the standard deviation of the angular intensity in the eye box BOX1 when the display device includes only one beam expander EPE2.
  • the standard deviation of the angular intensity distribution corresponding to the point OP1 is significantly lower (30%) than the angular intensity distribution difference of the comparative example Ref02.
  • Uniform position distribution means that when the input image is a uniform image, the output beam intensity received by the eye EYE1 at different positions (x, y) in the eye box BOX1 is equal. Uniform position distribution means that the brightness of a specific image point seen by the eye EYE1 at different positions in the eye box BOX1 is the same. The degree of uniform position distribution can be measured by the standard deviation of the brightness observed at different eye box positions. A lower standard deviation indicates higher uniformity.
  • the brightness of the displayed image point (P1') depends on the sum of the intensities of the first output beam B3aP1 output by the first beam expansion device EPE1 and the second output beam B3bP1 output by the second beam expansion device EPE2.
  • the position distribution of the output light OUT1 may be substantially uniform, so that when the eye EYE1 moves in the eye box, the sum of the intensities of the output beams B3aP1 and B3bP1 transmitted to the eye EYE1 is independent of the position (x, y) of the eye box BOX1.
  • Figure 5c shows the relationship between the standard deviation of the position distribution difference of the image brightness in the eye box of a display device and the thickness ratio of the two waveguide substrates under different refractive indices of the waveguide substrate of the first beam expansion device.
  • the standard deviation in Figure 5c represents the image intensity difference observed at different positions (x, y) of the eye box BOX1.
  • the input image IMG0 is uniform, that is, all image points of the input image IMG0 have equal brightness.
  • Ref03 shows the position intensity standard deviation in the eye box BOX1 when the display device includes only one beam expander EPE2.
  • the position intensity distribution standard deviation corresponding to the point OP1 is substantially lower (30%) than the position intensity distribution difference of the comparative example Ref03.
  • the values of the parameters may be selected according to the display criteria to be achieved.
  • the display criteria may include, for example, one or more of the following requirements:
  • the display device 500 may be arranged to display a monochrome image VIMG1.
  • the display device 500 may be arranged to display, for example, a green image VIMG1. In this case, there is no need to optimize the distribution uniformity between the different colors of the image.
  • the display device 500 may be configured to display a full-color image VIMG1.
  • the display device 500 may display an RGB image VIMG1, which includes a red (R) sub-image, a green (G) sub-image, and a blue (B) sub-image.
  • R red
  • G green
  • B blue
  • the uniformity of the distribution of different colors may also be used as a target for optimizing the parameters (tSUB1, tSUB2, n1, n2).
  • Fig. 6a shows a schematic diagram of a first beam expander EPE1.
  • the first beam expander EPE1 comprises a first diffractive element combination GRP1 for controlling the propagation direction of the output light beam.
  • the beam expander EPE1 comprises a first diffractive element combination, which is constructed on a first waveguide substrate SUB1.
  • the first diffractive element combination may comprise a first input element DOE1a, a first beam expander element DOE2a and a first output element DOE3a.
  • the first input element DOE1a has a grating period d1a.
  • the first input element DOE1a can be implemented by a diffractive surface relief grating G1a with a grating period d1a.
  • the grating G1a includes diffractive features F1a, which can be microscopic ridges, grooves and/or protrusions.
  • the grating G1a has a grating vector V1a.
  • the direction of the grating vector V1a can be specified, such as a first angle ⁇ 1a.
  • the input element DOE1a can have a first width w1a (in the direction SX) and a first height h1a (in the direction SY).
  • the first beam expander element DOE2a may have a grating period d2a.
  • the first beam expander element DOE2a may be implemented by a diffractive surface relief grating G2a having a grating period d2a.
  • the grating G2a has a diffractive feature F2a.
  • the grating G2a has a grating vector V2a.
  • the direction of the grating vector V2a may be specified by a second angle ⁇ 2a.
  • the beam expander element DOE2a may have a second width w2a and a second height h2a.
  • the first output element DOE3a may have a grating period d3a.
  • the first output element DOE3a may be implemented by a diffractive surface relief grating G3a having a grating period d3a.
  • the grating G3a includes a diffractive feature F3a.
  • the grating G3a has a grating vector V3a.
  • the direction of the grating vector V3a may be specified by a third angle ⁇ 3a.
  • the output element DOE3a may have a third width w3a and a third height h3a.
  • the size of the grating vector depends on the grating period of the diffraction grating of the diffraction element, and the direction of the grating vector depends on the orientation of the diffraction grating.
  • the size of the grating vector V1a depends on the grating period d1a of the diffraction grating G1a of the diffraction element DOE1a, and the direction ⁇ 1a of the grating vector V1a depends on the orientation of the diffraction grating G1a.
  • the first beam expander EPE1 includes a first diffraction element combination in the optical path, and the first diffraction element combination includes a first input element DOE1a, a first beam expander element DOE2a, and a first output element DOE3a.
  • the first input element DOE1a can receive input light beams B0P1 and B0P2 through the first main surface of the first beam expander EPE1.
  • Fig. 6b shows a schematic diagram of a second beam expander EPE2.
  • the second beam expander EPE2 comprises a second diffractive element combination GRP2 for controlling the propagation direction of the output light beam.
  • the second beam expander EPE2 comprises a second diffractive element combination, which is constructed on a second waveguide substrate SUB2.
  • the second diffractive element combination may comprise a second input element DOE1b, a second beam expander element DOE2b and a second output element DOE3b.
  • the first input element DOE1a and the second input element DOE1b may perform the same function, namely input coupling.
  • the second input element DOE1b may correspond to the first input element DOE1a.
  • the second input element DOE1b of the second beam expander EPE2 may correspond to the first input element DOE1a of the first beam expander EPE1.
  • the second beam expander element DOE2b of the second beam expander EPE2 may correspond to the first beam expander element DOE2a of the first beam expander EPE1.
  • the second output element DOE3b of the second beam expander EPE2 may correspond to the first output element DOE3a of the first beam expander EPE1.
  • the second input element DOE1b may have a grating period d1b.
  • the second input element DOE1b may be implemented by a diffractive surface relief grating G1b having a grating period d1b.
  • the grating G1b includes diffractive features F1b, which may be, for example, microscopic ridges, grooves and/or protrusions.
  • the grating G1b has a grating vector V1b.
  • the direction of the grating vector V1b may be specified, for example an angle ⁇ 1b.
  • the input element DOE1b may have a width w1b (in the direction SX) and a height h1b (in the direction SY).
  • the second beam expander element DOE2b may have a grating period d2b.
  • the second beam expander element DOE2b may be implemented by a diffractive surface relief grating G2b having a grating period d2b.
  • the grating G2b has a diffractive feature F2b.
  • the grating G2b has a grating vector V2b.
  • the direction of the grating vector V2b may be specified by an angle ⁇ 2b.
  • the beam expander element DOE2b may have a width w2b and a height h2b.
  • the second output element DOE3b may have a grating period d3b.
  • the second output element DOE3b may be implemented by a diffractive surface relief grating G3b having a grating period d3b.
  • the grating G3b includes diffractive features F3b.
  • the grating G3b has a grating vector V3b.
  • the direction of the grating vector V3b may be specified by an angle ⁇ 3b.
  • the output element DOE3b may have a width w3b and a height h3b.
  • each element (DOE1a, DOE2a, DOE3a) of the first diffractive element group (GRP1) may be identical to the shape of the corresponding element (DOE1b, DOE2b, DOE3b) of the second diffractive element group (GPR2). That is, the shape of the first input element DOE1a is the same as that of the second input element DOE1b, the shape of the first beam expander element DOE2a is the same as that of the second beam expander element DOE2b, and the shape of the first output element DOE3a is the same as that of the second output element DOE3b.
  • each element (DOE1a, DOE2a, DOE3a) of the first diffractive element combination (GRP1) can be equal to the area of the corresponding element (DOE1b, DOE2b, DOE3b) of the second diffractive element combination (GPR2), or equal to within a certain accuracy range, for example, the accuracy is better than 1%.
  • the area of the first input element DOE1a is equal to the area of the second input element DOE1b or equal to within a certain accuracy range
  • the area of the first beam expander element DOE2a is equal to the area of the second beam expander element DOE2b or equal to within a certain accuracy range
  • the area of the first output element DOE3a is equal to the area of the second output element DOE3b or equal to within a certain accuracy range.
  • the first waveguide substrate SUB1 and the second waveguide substrate SUB2 include a planar waveguide core layer.
  • the first waveguide substrate SUB1 and the second waveguide substrate SUB2 may include, for example, one or more cladding layers, one or more protective layers and/or one or more mechanical support layers.
  • the thickness tSUB1, tSUB2 may refer to the thickness of the planar waveguide core layer of the first waveguide substrate SUB1 and the second waveguide substrate SUB2.
  • the first waveguide substrate SUB1 and the second waveguide substrate SUB2 may include or essentially consist of a transparent solid material.
  • the first waveguide substrate SUB1 may include, for example, glass, polycarbonate or polymethyl methacrylate (PMMA).
  • the diffractive optical element may be formed by molding, embossing and/or etching.
  • the diffractive optical element may be realized by one or more surface diffraction gratings.
  • the diffractive optical element of the first beam expander EPE1 may be a surface diffraction grating, which may be constructed on the same main surface (SRF1a or SRF1b) of the waveguide substrate SUB1. Constructing the elements on the same main surface can simplify production.
  • the diffraction element may be produced by using photolithography.
  • one or more imprinting tools may be produced by electron beam lithography, and the diffraction grating may be formed by using one or more imprinting tools.
  • the first input element DOE1a, the first beam expanding element DOE2a, and the first output element DOE3a of the first beam expanding device EPE1 can be formed by processing through the stamping tool TOOL1, and the diffraction element second input element DOE1b, the second beam expanding element DOE2b, and the second output element DOE3b of the second beam expanding device EPE2 can also be formed by processing through the same stamping tool TOOL1.
  • Using the same imprint tool TOOL1 to produce the first beam expander EPE1 and the second beam expander EPE2 can simplify production.
  • Using the same imprint tool TOOL1 to produce the first beam expander EPE1 and the second beam expander EPE2 can also ensure that the direction of the output beam formed by the second beam expander EPE2 is consistent with the direction of the output beam formed by the first beam expander EPE1.
  • the method of manufacturing a display device may include forming the first input element DOE1 a and the second input element DOE1 b using the same imprint tool TOOL1 .
  • the first diffraction element group GRP1 (DOE1a, DOE2a, DOE3a) of the first beam expansion device EPE1 and the second diffraction element group GRP2 (DOE1b, DOE2b, DOE3b) of the second beam expansion device EPE2 can be formed by using the same imprinting tool TOOL1.
  • the tool TOOL1 can be used as a mold or an imprinting mold for forming a surface relief grating of a diffractive element.
  • the diffractive features of the element can be formed by pressing a waveguide SUB1 or a waveguide grating between the tool TOOL1 and the backing COU1.
  • the backing COU1 can support the first waveguide substrate SUB1 or the second waveguide substrate SUB2 during the pressing process.
  • the first waveguide substrate SUB1 and the second waveguide substrate SUB2 can be preheated to facilitate the formation of the diffraction microstructure.
  • the coating of the first waveguide substrate SUB1 and the second waveguide substrate SUB2 can be, for example, cured to make the formed diffraction microstructure more solid.
  • the tool TOOL1 may include a first region RF1 for forming a first input element DOE1a and a second input element DOE1b.
  • the tool TOOL1 may include a second region RF2 for forming a first beam expander element DOE2a and a second beam expander element DOE2b.
  • the tool TOOL1 may include a third region RF3 for forming a first output element DOE3a and a second output element DOE3b.
  • the first region RF1, the second region RF2 and the third region RF3 may include microscopic protrusions for forming diffractive elements of the first beam expander EPE1 and the second beam expander EPE2.
  • Figures 7a to 7e are three-dimensional schematic diagrams of an optical engine generating an input light beam.
  • the optical engine ENG1 can form an input light IN1, which represents an input image IMG0.
  • the optical engine ENG1 can form an input image IMG0 and can convert the input image IMG0 into multiple light beams B0P1, B0P2 of the input light IN1.
  • the input light IN1 may include multiple input light beams (B0P1, B0P2) representing the input image IMG0.
  • the optical engine ENG1 may include a display element DISP1 to generate an input image IMG0.
  • the input image IMG0 may include multiple image points P1, P2 arranged in a two-dimensional array.
  • the optical engine ENG1 may include a collimating optical device LNS1 to form multiple input light beams (B0P1, B0P2) from the image points P1, P2 of the input image IMG0.
  • the input image IMG0 may include a center point P0 and four corner points P1, P2, P3, and P4.
  • P1 may represent the upper left corner point.
  • P2 may represent the upper right corner point.
  • P3 may represent the lower left corner point.
  • P4 may represent the lower right corner point.
  • the input image IMG0 may include, for example, graphic characters "F", "G", and "H”.
  • the input image IMG0 may represent displayed information.
  • the input image IMG0 may be a monochrome image or a multi-color image.
  • the input image IMG0 may be, for example, an RGB image, which may include a red (R) partial image, a green (G) partial image, and a blue (B) partial image.
  • the input image IMG0 may be formed by, for example, modulating a laser or modulating light obtained from one or more light emitting diodes.
  • the optical engine ENG1 may provide input light IN1, which may include a plurality of substantially collimated light beams B0P0, B0P1, B0P2, B0P3, B0P4.
  • the light B0P0 of the center point P0 may propagate in the direction of the optical axis AX0 of the optical engine ENG1.
  • the displayed virtual image VIMG1 may have a center point P0' and four corner points P1', P2', P3', P4'.
  • the input light IN1 may include a plurality of partial light beams corresponding to the points P0, P1, P2, P3, P4 of the input image IMG0.
  • the beam expanders EPE1 and EPE2 may form the point P0' of the displayed virtual image VIMG1 by, for example, diffracting and guiding the light at the point P0 of the input image IMG0.
  • the beam expander EPE1 may form the points P1', P2', P3', P4', for example, by respectively diffracting and guiding the light at the points P1, P2, P3, P4.
  • the output light OUT1 may include a series of output light beams B3aP0, B3aP1, B3aP2, B3aP3, B3aP4, B3bP0, B3bP1, B3bP2, B3bP3, B3bP4.
  • the first output element DOE3a of the first beam expansion device EPE1 can form output beams B3aP0, B3aP1, B3aP2, B3aP3, B3aP4 by diffracting the guided light out of the waveguide plate SUB1.
  • the second output element DOE3b of the second beam expansion device EPE1 can form output beams B3bP0, B3bP1, B3bP2, B3bP3, B3bP4 by diffracting the guided light out of the waveguide plate SUB2.
  • the output light OUT1 can be regarded as a combination of output light beams provided by two or more first beam expansion devices EPE1 and second beam expansion devices EPE2.
  • Output beams B3aP0 and B3bP0 may be formed from light of input beam B0P0, which corresponds to image point P0 of input image IMG0.
  • Display device 500 may be arranged so that the direction of output beam B3aP0 is parallel to the direction of output beam B3bP0.
  • Output beams B3aP0 and B3bP0 may appear to originate from point P0' of virtual image VIMG1.
  • the output light beams B3aP1 and B3bP1 may be parallel to each other, and may correspond to the image point P1 of the input image IMG0 or the image point P1 ′ of the virtual image VIMG1 .
  • the output light beams B3aP2 and B3bP2 may be parallel to each other, and may correspond to the image point P2 of the input image IMG0 or the image point P2' of the virtual image VIMG1.
  • the output light beams B3aP3 and B3bP3 may be parallel to each other, and may correspond to the image point P3 of the input image IMG0 or the image point P3' of the virtual image VIMG1.
  • the output light beams B3aP4 and B3bP4 may be parallel to each other, and may correspond to the image point P4 of the input image IMG0 or the image point P4' of the virtual image VIMG1.
  • Figure 7g is a schematic diagram of the angular width of a displayed virtual image
  • Figure 7h is a schematic diagram of the angular height of a displayed virtual image.
  • the angular width of the displayed virtual image VIMG1 is ⁇ VIMG1
  • the angular height is ⁇ VIMG1.
  • the displayed virtual image VIMG1 may have a first corner point P1', for example on the left side of image VIMG1, and a second corner point P2', for example on the right side of image VIMG1.
  • the angular width ⁇ VIMG1 of virtual image VIMG1 may be equal to the horizontal angle between the propagation directions of output beams B3aP and B3aP2.
  • the displayed virtual image VIMG1 may have an upper corner point P1' and a lower corner point P3'.
  • the angular height ⁇ VIMG1 of the virtual image VIMG1 may be equal to the vertical angle between the directions of the output beams B3aP1 and B3aP3.
  • the direction of the light beam can be specified, for example, by the direction angles ⁇ and ⁇ , which can represent the angle between the direction of the light beam and the reference plane REF1.
  • the reference plane REF1 can be defined, for example, as the plane where the directions SZ and SY lie.
  • the angle ⁇ can represent the angle between the direction of the light beam and the reference plane REF2.
  • the angle ⁇ B3a,P1 and the angle ⁇ B3a,P1 represent the direction of the output light beam B3aP1, which corresponds to the image point P1.
  • the reference plane REF2 may be defined as, for example, a plane where the directions SZ and SX are located.
  • the direction of the light beam emitted by the image point P1 may be represented by a direction angle ⁇ B3,P1, ⁇ B3,P1.
  • the input image IMG0 may represent displayed information.
  • the input image IMG0 may represent, for example, graphics and/or text.
  • the input image IMG0 may represent, for example, a video.
  • the light engine ENG1 may be arranged to generate still images and/or videos.
  • the light engine ENG1 may generate a real main image IMG0 from a digital image.
  • the light engine ENG1 may receive one or more digital images, for example from an Internet server or a smartphone.
  • the display DISP1 may include a two-dimensional array of display pixels.
  • the display DISP1 may include a light emitting A two-dimensional array of display pixels.
  • the light engine ENG1 may include, for example, one or more light emitting diodes (LEDs).
  • the display DISP1 may include, for example, one or more microdisplay imagers, such as liquid crystal on silicon (LCOS), a liquid crystal display (LCD), a digital micromirror device (DMD).
  • the display DISP1 may generate an input image IMG0, for example, with a resolution of 1280 ⁇ 720 (HD).
  • the display DISP1 may generate an input image IMG0, for example, with a resolution of 1920 ⁇ 1080 (full HD).
  • the display DISP1 may generate an input image IMG0, for example, with a resolution of 3840 ⁇ 2160 (4K UHD).
  • the input image IMG0 may include multiple image points P0, P1, P2...and so on.
  • the light engine ENG1 may include a collimating optical device LNS1 to form a light beam from each image pixel.
  • the engine ENG1 may include a collimating optical device LNS1 to form a substantially collimated light beam from the light of the image point.
  • the first beam expansion device EPE1 and the second beam expansion device EPE2 can be implemented by only two diffraction elements.
  • the first beam expansion device EPE1 may include a first input element DOE1a to form a first guided light B1a, wherein the first output element DOE3a may be arranged to form an output light OUT1 by diffracting the first guided light B1a out of the first waveguide substrate SUB1.
  • the first beam expansion device EPE1 can be implemented without the first beam expansion element DOE2a.
  • the first beam expansion device EPE1 can be implemented by two diffraction elements, namely the first input element DOE1a and the first output element DOE3a.
  • the second beam expansion device EPE2 can be implemented by the second input element DOE1b and the second output element DOE3b without the second beam expansion element DOE2b.
  • the second output element DOE3b can diffract the guided light B1b out of the second waveguide substrate SUB2.
  • the first beam expansion device EPE1 may include four diffraction elements for controlling the direction of the output light beam.
  • the four elements may form a light beam transmission optical path to realize the transmission of the light beam from the first input element DOE1a to the first output element DOE3a.
  • the first input element DOE1a may form the transmission light B1a by diffracting the input light IN1.
  • the first beam expansion element DOE2a may form the extended transmission light B2a by diffracting the transmission light B1a.
  • the additional beam expansion element may form the additional transmission light by diffracting the extended transmission light B2a.
  • the first output element DOE3a may form the output light by diffracting the additional transmission light out of the waveguide plate SUB1.
  • the second beam expansion device EPE2 may also include four diffraction elements for controlling the direction of the output light beam.
  • An embodiment of the present application provides a display device (500), comprising:
  • a beam expander stack for expanding the input light (IN1) by diffraction to form an output light (OUT1), wherein the output light (OUT1) includes a series of output beams representing the input image (IMG0) (B3aP1, B3aP2, B3bP1, B3bP2);
  • the beam expander stack (STC1) comprises a first beam expander (EPE1) and a second beam expander (EPE2);
  • the first beam expansion device (EPE1) comprises a first diffraction element combination (GRP1) for controlling the propagation direction of the first output light beam (B3aP1, B3aP2);
  • the second beam expansion device comprises a second diffraction element combination (GRP2) for controlling the propagation direction of the second output light beam (B3bP1, B3bP2);
  • the first beam expansion device (EPE1) comprises a first input element (DOE1a) for diffracting the input light (IN1) into a first waveguide substrate (SUB1) of the first beam expansion device (EPE1);
  • the first beam expanding device (EPE1) is configured to allow part of the input light (IN1) to be transmitted through the first beam expanding device (EPE1) to the second beam expanding device (EPE2);
  • the second beam expansion device (EPE2) comprises a second input element (DOE1b) for diffracting a portion of the input light (IN1) transmitted through the first beam expansion device and inputting it into a second waveguide substrate (SUB2) of the second beam expansion device (EPE2);
  • the grating period (d1a, d2a, d3a) of each diffraction element (DOE1a, DOE2a, DOE3a) in the first diffraction element combination (GRP1) is equal to the grating period (d1b, d2b, d3b) of each corresponding diffraction element (DOE1b, DOE2b, DOE3b) in the second diffraction element combination (GRP2).
  • the refractive index (n1) of the first input element (DOE1a) is different from the refractive index (n2) of the second input element (DOE1b).
  • the thickness (tSUB1) of the waveguide substrate (SUB1) of the first beam expansion device (EPE1) is different from the thickness (tSUB2) of the waveguide substrate (SUB2) of the second beam expansion device (EPE2).
  • At least one of the first waveguide substrate (SUB1) and the second waveguide substrate (SUB2) includes two or more materials (S11, S12).
  • the material forming the first waveguide substrate (SUB1) is the same as the material forming the second waveguide substrate (SUB2).
  • the material (S11, S12) of the first waveguide substrate (SUB1) is a transparent material to achieve light beam conduction.
  • the first waveguide substrate (SUB1) comprises one or a combination of glass, polycarbonate or polymethyl methacrylate (PMMA).
  • the thickness (tSUB1) of the first waveguide substrate (SUB1) and the thickness (tSUB2) of the second waveguide substrate (SUB2) are selected; and/or
  • the refractive index (n1) of the first input element (DOE1a) and the refractive index (n2) of the second input element (DOE1b) are selected so that the output light of the second beam expander (EPE2) at least partially compensates the output light of the first beam expander (EPE1) to make the output light (OUT1) more uniform.
  • each diffraction element DOE1a, DOE2a, The shape of DOE3a
  • DOE1a, DOE2a, The shape of DOE3a is the same as the shape of the corresponding diffractive element (DOE1b, DOE2b, DOE3b) in the second diffractive element combination (GRP2).
  • the difference between the area of each diffraction element (DOE1a, DOE2a, DOE3a) in the first diffraction element combination (GRP1) and the area of the corresponding diffraction element (DOE1b, DOE2b, DOE3b) in the second diffraction element combination (GRP2) is less than 1%.
  • the first diffractive element combination (GRP1) comprises:
  • DOE2a a first beam expanding element
  • DOE3a a first output element (DOE3a), configured to diffract the second guided light (B2a) and output the first waveguide substrate (SUB1) to form output light (OUT1);
  • the second diffractive element combination (GRP2) comprises:
  • a second input element configured to diffract a portion of the input light (IN1) transmitted through the first diffraction waveguide (EPE1) and input the portion into the second waveguide substrate (SUB2), so as to form a third guided light (B1b) transmitted in the second waveguide substrate (SUB2);
  • DOE2b a second beam expanding element
  • the second output element (DOE3b) is used for diffracting the fourth guided light (B2b) and outputting it to the second waveguide substrate (SUB2) to form output light (OUT1).
  • the first waveguide substrate (SUB1) and the second waveguide substrate (SUB2) include a planar waveguide core layer
  • the thickness of the first waveguide substrate (SUB1) is equal to the thickness of the planar waveguide core layer of the first waveguide substrate (SUB1)
  • the thickness of the second waveguide substrate (SUB2) is equal to the thickness of the planar waveguide core layer of the second waveguide substrate (SUB2).
  • the first waveguide substrate (SUB1) comprises one or more cladding layers, one or more protection layers and/or one or more mechanical support layers.
  • the second waveguide substrate comprises one or more cladding layers, one or more protection layers and/or one or more mechanical support layers.
  • the light engine (ENG1) comprises a display screen (DISP1) and a collimating lens group (LNS1), wherein the display screen (DISP1) is configured to display an input image (IMG0), and the collimating lens group (LNS1) is used to collimate image points.
  • the embodiment of the present application further provides a virtual image display method, which is applied to a display device (500), wherein the display device is the display device (500) described above, and the display method comprises:
  • input light (IN1), the input light comprising light beams (B0P1, B0P2) corresponding to different image points (P1, P2) on an input image (IMG0);
  • the beam expander stack (STC1) is used to diffract and expand the input light (IN1) to form output light (OUT1).
  • the embodiment of the present application also provides a method for manufacturing a display device (500), the method for manufacturing the display device (500) as described above, the method comprising:
  • the first input element (DOE1a) and the second input element (DOE1b) are manufactured using the same imprint master (TOOL1).
  • the manufacturing method further comprises using the same imprinting master (TOOL1) to manufacture the first diffraction element combination (GRP1) and the second diffraction element combination (GRP2).
  • TOOL1 same imprinting master
  • GRP1 first diffraction element combination
  • GRP2 second diffraction element combination
  • the manufacturing method further comprises:
  • a waveguide plate (SUB1) or (SUB2) is pressed between the imprint master (TOOL1) and the backing (COU1) to form the diffractive features of the element.
  • the manufacturing method further comprises:
  • the first waveguide substrate (SUB1) and the second waveguide substrate (SUB2) are formed into diffraction microstructures by preheating.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

一种显示设备（500）、虚拟图像显示方法和显示设备（500）的制造方法，显示设备（500）包括光引擎（ENG1）、第一扩束装置（EPE1）和第二扩束装置（EPE2）；第一扩束装置（EPE1）包括第一衍射元件组合（GRP1）和用于将输入光（IN1）衍射输入到第一扩束装置（EPE1）内的第一输入元件（DOE1a）；第二扩束装置（EPE2）包括第二衍射元件组合（GRP2）和用于将输入光（IN2）衍射到第二扩束装置（EPE2）内的第二输入元件（DOE1b）；第一衍射元件组合（GRP1）与第二衍射元件组合（GRP2）的光栅周期相等。

Description

显示设备、虚拟图像显示方法和显示设备的制造方法
本申请要求于2022年10月12日提交中国专利局、申请号为202211248634.X、发明名称为“显示设备、虚拟图像显示方法和显示设备的制造方法”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本发明涉及虚拟显示技术领域，特别涉及一种显示设备、虚拟图像显示方法和显示设备的制造方法。
背景技术
如图1所示，图1为一种已知的显示设备，一种已知的图像显示设备包括一个光引擎ENG1和一个衍射扩束装置EPE0。所述显示设备通过衍射扩展由光引擎ENG1提供的图像光束来显示虚拟图像。衍射扩束装置EPE0提供一个扩大了的可观测区域(以下称为眼盒)BOX1来观察虚拟图像。衍射扩束装置EPE0包括一个波导基板SUB0，一个输入元件DOE1，和一个输出元件DOE3。光引擎ENG1形成输入光IN1。输入光包括对应输入图像(IMG0)上不同图像点(P1，P2)的往不同方向传输的输入光束(B0P1,B0P2)。
扩束装置EPE0通过衍射扩展输入光IN1形成输出光。衍射扩束装置EPE0通过衍射扩展输入光束B0P1形成输出光束B3P1。衍射扩束装置EPE0通过衍射扩展输入光束B0P2形成输出光束B3P2。
输入元件DOE1通过衍射输入光IN1形成传导光(B1P1，B1P2)。传导光(B1P1，B1P2)在波导基板SUB0内传输。输出元件DOE3通过将传导光(B1P1，B1P2)衍射输出波导基板SUB0形成输出光束(B3P1，B3P2)。当输出光束(B3P1，B3P2)进入到观察者的眼睛时，观察者可以看到所显示的虚拟图像。对应不同图像点的输出光束的集合共同组成输出光。
输出光可能表现出空间上或角度分布上的不均匀。例如，输出光束B3P1可能随到输入元件DOE1的距离增加而越来越弱。又例如，从输出单元DOE3某一固定位置输出的对应图像像点P1的输出光束B3P1的能量可能弱于从该位置输出的对应图像像点P2的输出光束B3P2的能量，即使对应该输出光束的输入光束(B0P1,B0P2)具有相同的能量。
发明内容
本发明提供一种显示设备、虚拟图像显示方法和显示设备的制造方法。
本发明提出一种显示设备(500)，包括：
光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)；
扩束装置叠层(STC1)，通过衍射扩展所述输入光(IN1)形成输出光(OUT1)，所述输出光(OUT1)包括一系列代表所述输入图像(IMG0)的输出光束(B3aP1,B3aP2,B3bP1,B3bP2)；
所述扩束装置叠层(STC1)包括一个第一扩束装置(EPE1)和一个第二扩束装置(EPE2)；
所述第一扩束装置(EPE1)包括第一衍射元件组合(GRP1)，用于控制第 一输出光束(B3aP1,B3aP2)的传播方向；
所述第二扩束装置(EPE2)包括第二衍射元件组合(GRP2)，用于控制第二输出光束(B3bP1,B3bP2)的传播方向，
所述第一扩束装置(EPE1)包括一个第一输入元件(DOE1a)，用于将所述输入光(IN1)衍射输入到所述第一扩束装置(EPE1)的波导基板(SUB1)内；
所述第一扩束装置(EPE1)被设置为使部分所述输入光(IN1)透过所述第一扩束装置(EPE1)传输到所述第二扩束装置(EPE2)；
所述第二扩束装置(EPE2)包括一个第二输入元件(DOE1b)，用于将透过所述第一扩束装置的部分所述输入光(IN1)衍射输入到所述第二扩束装置(EPE2)的波导基板(SUB2)内；
其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与所述第二衍射元件组合(GRP2)中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。
本发明还提出一种虚拟图像显示方法，应用于显示设备(500)，所述显示设备为根据上述任一项所述的显示设备(500)，所述显示方法包括：
形成输入光(IN1)，所述输入光包括对应输入图像(IMG0)上不同图像点(P1，P2)的光束(B0P1,B0P2)；
采用所述扩束装置叠层(STC1)衍射扩展所述输入光(IN1)以形成输出光(OUT1)。
本发明提出一种显示设备的制造方法，所述制造方法用于制造如上述任一项所述的显示设备(500)，所述制造方法包括：
采用同一个压印母版(TOOL1)制作所述第一输入元件(DOE1a)和所述第二输入元件(DOE1b)。
本发明提出的显示设备包括光引擎，用于形成输入光。所述输入光包括与输入图像像点对应的一系列输入光束。各输入光束的传播方向取决于与其对应的图像像点的位置，各输入光束的强度对应于相应像点的亮度。
所述显示设备包括由多个扩束装置重叠形成的叠层，用于接受输入光并形成输出光。输出光包括一系列与输入图像像点对应的输出光束。所述扩束装置叠层通过衍射扩展输入光束形成输出光束。
所述扩束装置叠层包括第一扩束装置和第二扩束装置，第一扩束装置包括一个第一输入元件，所述第一输入元件将输入光衍射输入第一扩束装置的波导基板内。所述第一输入元件允许一部分输入光透过所述第一扩束装置传输到第二扩束装置。所述第二扩束装置包括第二输入元件，所述第二输入元件将透过第一扩束装置的输入光衍射输入到第二扩束装置的波导基板内。
所述第一扩束装置包括一个第一输出元件，通过衍射在所述第一扩束装置的波导基板内传输的传导光，形成第一输出光束。所述第二扩束装置包括一个第二输出元件，通过衍射在所述第二扩束装置的波导基板内传输的传导光，形成第二 输出光束。被第一输出元件输出的所述第一输出光束可以穿过所述第二扩束装置并传输到观察者的眼睛中。总的输出光束由所述第一输出光束或所述第二输出光束共同组成。
附图说明
为了更清楚地说明本发明实施例技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。
图1为一种已知的显示设备；
图2为本申请实施例所提出一种包括衍射扩束装置叠层的显示设备的侧视图；
图3a为本申请实施例所提出一种包括衍射扩束装置叠层的显示设备的三维示意图；
图3b为对应于图3a中所示第二衍射扩束装置中一种传导光传输的三维示意图；
图4a为本申请实施例所提出的一种显示设备的侧视图，其中，第一扩束装置波导基板的厚度不同于第二扩束装置波导基板的厚度。
图4b为本申请实施例所提出的一种显示设备的侧视图,其中，第一扩束装置的波导基板由两个不同材料层构成；
图5a为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中平均亮度与两个波导基板厚度比值的关系曲线；
图5b为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中图像亮度角分布差异的标准差与两个波导基板厚度比值的关系；
图5c为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中图像亮度位置分布差异的标准差与两个波导基板厚度比值的关系；
图6a为本申请实施例提出的一种显示设备所包括的第一扩束装置的尺寸示意图；
图6b为本申请实施例提出的一种显示设备所包括的第二扩束装置的尺寸示意图；
图6c为采用一个压印母版加工一种第一扩束装置的三维示意图；
图6d为采用与图6c中相同的压印母版加工一种第二扩束装置的三维示意图；
图7a到图7e为一种光引擎生成输入光束的三维示意图；
图7f为一种观察所显示的虚拟图像的三维示意图；
图7g为一种所显示的虚拟图像的角度宽度示意图；
图7h为一种所显示的虚拟图像的角度高度示意图。
具体实施方式
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本申请保护的范围。
如图2所示，图2为本申请实施例所提出一种包括衍射扩束装置叠层的显示设备的侧视图。显示设备500包括一个光引擎ENG1，以及一个由第一扩束装置EPE1和第二扩束装置EPE2组成的扩束装置叠层STC1。
光引擎ENG1可以提供输入光IN1，该输入光包括对应于图像IMG0中第一图像像点P1和第二图像像点P2的输入光束B0P1,B0P2。显示设备500还可以接受由光引擎ENG1产生的输入光IN1。
叠层STC1可以包括两个或两个以上数量的扩束装置。所述叠层STC1包括至少一个第一扩束装置EPE1和一个第二扩束装置EPE2。由第一扩束装置EPE1和第二扩束装置EPE2组成的扩束装置叠层STC1可以提供输出光OUT1。可以操作第一扩束装置EPE1和第二扩束装置EPE2，使得输出光OUT1中包括与第一图像像点P1和第二图像像点P2对应的输出光束B3aP1,B3aP2,B3bP1,B3bP2。
如图3a所示，图3a为本申请实施例所提出一种包括衍射扩束装置叠层的显示设备的三维示意图。当输出光OUT1进入到观察者的眼睛EYE1时，观察者可以看到所显示的虚拟图像VIMG1。所述显示设备500具有一个眼盒BOX1，眼盒代表观察者可以放置自己眼睛EYE1的范围，该范围可以看到所显示的完整虚拟图像。
所述第一扩束装置EPE1包括一个第一波导基板SUB1，所述第一波导基板SUB1进一步包括几个用于控制光线传播方向的衍射元件。所述第一波导基板SUB1可以包括一个第一输入元件DOE1a，一个第一扩束元件DOE2a和一个第一输出元件DOE3a。所述第一输入元件DOE1a可以通过将输入光IN1衍射输入到第一扩束装置EPE1的第一波导基板SUB1内，以形成在第一波导基板SUB1内传输的第一传导光B1a。所述第一扩束元件DOE2a通过衍射第一传导光B1a形成第二传导光B2a。所述第一输出元件DOE3a通过将所述第二传导光B2a衍射出第一波导基板SUB1，形成输出光OUT1。通过第一输出元件DOE3a衍射输出的输出光OUT1可以包括输出光束，例如B3aP1,B3aP2，如图7f所示，图7f为一种观察所显示的虚拟图像的三维示意图。所述第一扩束装置EPE1可以包括一个由衍射元件第一输入元件DOE1a、第一扩束元件DOE2a和第一输出元件DOE3a组成的第一衍射元件组合GRP1，如图6a所示，图6a为本申请实施例提出的一种显示设备所包括的第一扩束装置的尺寸示意图。该第一衍射元件组合GRP1用于控制输出光OUT1的传输方向。
有一部分输入光IN1可以透过所述第一扩束装置EPE1并传输到第二扩束装置EPE2的第二输入元件DOE1b上。这部分透过所述第一扩束装置EPE1并传输到第二输入单元DOE1b的输入光IN1可以被称为透过输入光，记为IN2。
所述第二扩束装置EPE2包括一个第二波导基板SUB2，所述第二波导基板SUB2可以进一步包括一个第二输入元件DOE1b，一个第二扩束元件DOE2b和一个第二输出元件DOE3b。所述第二输入元件DOE1b可以通过将透过输入光IN2衍射输入到第二波导基板SUB2内，形成第三传导光B1b。所述第二扩束元件DOE2b通过衍射第三传导光B1b形成第四传导光B2b，如图3b所示，图3b为对应于图3a中所示第二衍射扩束装置中一种传导光传输的三维示意图。所述第二输出元件DOE3b通过将所述第四传导光B2b衍射出第二波导基板SUB2，形成输出光OUT1。
通过第二输出元件DOE3b衍射输出的输出光OUT1可以包括输出光束，例如B3bP1,B3bP2，如图7f所示。所述第二扩束装置EPE2可以包括一个由衍射元件DOE1b、DOE2b和DOE3b组成的第二衍射元件组合GRP2，如图6b所示，图6b为本申请实施例提出的一种显示设备所包括的第二扩束装置的尺寸示意图。该第二衍射元件组合GRP2用于控制输出光OUT1的传输方向。
通过第一扩束装置EPE1的第一输出元件DOE3a衍射输出的输出光可以透过第二扩束装置EPE2的第二输出元件DOE3b，并传输到观察者的眼睛中。显示设备500的总体输出光可以看成是第一扩束装置EPE1的输出光与第二扩束装置EPE2的输出光的组合。
SX，SY和SZ代表正交方向。所述第一波导基板SUB1所在平面可以在由SX和SY定义的平面。
第一扩束装置EPE1的第一波导基板SUB1具有两个相互平行的主平面SRF1a和SRF2a，如图4a所示，图4a为本申请实施例所提出的一种显示设备的侧视图，其中，第一扩束装置波导基板的厚度不同于第二扩束装置波导基板的厚度。第二扩束装置EPE2的第二波导基板SUB2具有两个相互平行的主平面SRF1b和SRF2b。
LC1和LC2表示一个更低的耦合效率，HC1和HC2表示一个更高的耦合效率。
对应于图像上不同的P1和P2像点的输入光束B0P1、B0P2朝不同的方向传输。所述第一输入元件DOE1a可能会以不同的衍射效率将输入光束B0P1、B0P2耦入到第一波导基板SUB1中。例如，第一输入元件DOE1a可能以一个更低的耦合效率LC1将输入光束B0P1耦入到第一波导基板SUB1中，而第一输入元件DOE1a可能以一个更高的耦合效率HC1将输入光束B0P2耦入到第一波导基板SUB1中。
所述第二扩束装置EPE2的第二输入元件DOE1b可能会以不同的衍射效率将输入光束B0P1、B0P2耦入到第二波导基板SUB2中。例如，第二输入元件DOE1b可能以一个更高的耦合效率HC2将输入光束B0P1耦入到第二波导基板SUB2中，而第一输入元件DOE1a可能以一个更低耦合效率LC2将输入光束B0P2耦入到第二波导基板SUB2中。
第一耦合效率函数ηEPE1(x,y,ψ,θ)表示第一扩束装置EPE1耦合输入光束并形成输出光束的效率，该效率函数是第一输出元件DOE3a位置(x,y)的函数，同时是输出光束传播方向(ψ,θ)的函数。所述位置可以具体表示为，例如位置坐标值(x,y)。所述光束传播方向可以具体表示为角度(ψ,θ)。
第二耦合效率函数ηEPE2(x,y,ψ,θ)表示第二扩束装置EPE2耦合输入光束并形成输出光束的效率，该效率函数是第二输出元件DOE3b位置(x,y)的函数，同时是输出光束传播方向(ψ,θ)的函数。
第一波导基板SUB1可以具有第一厚度tSUB1。第二波导基板SUB2可以具有第二厚度tSUB2。第一输入元件DOE1a可以具有第一折射率n1，第二输入元件DOE1b可以具有第二折射率n2，如图4a和图4b所示，图4b为本申请实施例所提出的一种显示设备的侧视图,其中，第一扩束装置的波导基板由两个不同材料层构成。衍射元件的折射率指该衍射元件微小衍射结构的折射率。
可以选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2和/或第一扩束装置EPE1的第一波导基板SUB1的第一厚度tSUB1和第二扩束装置EPE2的第二波导基板SUB2的第二厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)不同于第一耦合效率函数ηEPE1(x,y,ψ,θ)。示例性的，在一些实施例中，可以通过选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)不同于第一耦合效率函数ηEPE1(x,y,ψ,θ)。在一些实施例中，可以通过选择第一波导基板SUB1的第一厚度tSUB1和第二波导基板SUB2的第二厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)不同于第一耦合效率函数ηEPE1(x,y,ψ,θ)。在其他一些实施例中，可以通过选择第一折射率n1和第二折射率n2的值，以及选择第一厚度tSUB1和第二厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)不同于第一耦合效率函数ηEPE1(x,y,ψ,θ)。
可以选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2和/或第一扩束装置EPE1的第一波导基板SUB1的第一厚度tSUB1和第二扩束装置EPE2的第二波导基板SUB2的厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)至少部分地补偿第一耦合效率函数ηEPE1(x,y,ψ,θ)的位置和/或角度分布不均匀的情况。示例性的，在一些实施例中，可以通过选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)至少部分地补偿第一耦合效率函数ηEPE1(x,y,ψ,θ)的位置和/或角度分布不均匀的情况。在一些实施例中，可以通过选择第一波导基板SUB1的第一厚度tSUB1和第二波导基板SUB2的第二厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)至少部分地补偿第一耦合效率函数ηEPE1(x,y,ψ,θ)的位置和/或角度分布不均匀的情况。在其他一些实施例中，可以通过选择第一折射率n1和第二折射率n2的值，以及选择第一厚 度tSUB1和第二厚度tSUB2的值，使得第二耦合效率函数ηEPE2(x,y,ψ,θ)至少部分地补偿第一耦合效率函数ηEPE1(x,y,ψ,θ)的位置和/或角度分布不均匀的情况。
可以选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2和/或第一扩束装置EPE1的第一波导基板SUB1的第一厚度tSUB1和第二扩束装置EPE2的第二波导基板SUB2的厚度tSUB2，使得第二扩束装置的输出光OUT1至少部分地补偿第一扩束装置输出光OUT1的分布不均匀的情况。示例性的，在一些实施例中，可以通过选择第一输入元件DOE1a的第一折射率n1和第二输入元件DOE1b的第二折射率n2的值，使得第二扩束装置的输出光OUT1至少部分地补偿第一扩束装置输出光OUT1的分布不均匀的情况。在一些实施例中，可以通过选择第一波导基板SUB1的第一厚度tSUB1和第二波导基板SUB2的第二厚度tSUB2的值，使得第二扩束装置的输出光OUT1至少部分地补偿第一扩束装置输出光OUT1的分布不均匀的情况。在其他一些实施例中，可以通过选择第一折射率n1和第二折射率n2的值，以及选择第一厚度tSUB1和第二厚度tSUB2的值，使得第二扩束装置的输出光OUT1至少部分地补偿第一扩束装置输出光OUT1的分布不均匀的情况。
例如，当输出光对应于某一单一像点(例如P1)时，扩束装置叠层STC1可以被设置为至少部分补偿从靠近第一输入元件DOE1a的区域(NEAR1)耦出的光束能量和远离第一输入元件DOE1a的区域(FAR1)耦出的光束能量的差异。
如图3a和3b所示，显示设备500包括一个光引擎ENG1，以及一个由不同第一扩束装置EPE1和第二扩束装置EPE2组成的扩束装置叠层STC1。
光引擎ENG1可以包括一个显示屏DISP1以及准直透镜组LNS1。显示屏DISP1可以被设置为显示输入图像IMG0。显示屏DISP1还可以被称为微显示器。显示屏DISP1还可以被称为空间光调制器。输入图像IMG0还可以被称为初始图像。输入图像IMG0可以包括一系列图像像点，例如，P1和P2。光引擎ENG1可以包括准直透镜组LNS1，准直透镜组LNS1用于准直图像像点，例如P1、P2所发光，形成输入光。光引擎ENG1形成输入光IN1，该输入光包括多个输入光束，这些输入光束对应于输入图像IMG0上的不同像点，例如P1、P2。
所述光引擎ENG1可以被光学耦合到第一输入元件DOE1a和第二输入元件DOE1b上。第一扩束装置EPE1、第二扩束装置EPE2组成的扩束装置叠层STC1可以携带从光引擎ENG1获得的虚拟图像并传输到观察者的眼睛EYE1。第一扩束装置EPE1和第二扩束装置EPE2可以扩展可观看光瞳，从而扩大眼盒BOX1。
第一扩束装置EPE1可以包括衍射元件中第一输入元件DOE1a、第一扩束元件DOE2a、第一输出元件DOE3a。第一输入元件DOE1a通过衍射输入光IN1形成第一传导光B1a。第一扩束元件DOE2a通过衍射第一传导光B1a形成第二传导光B2a。第一输出元件DOE3a通过衍射第二传导光B2a形成输出光束(B3aP1,B3aP2)。
输入光束IN1的一部分，透过输入光IN2可以透过第一输入元件DOE1a并传输到第二输入元件DOE1b上。透过输入光IN2可以大体上沿着例如SZ的方向传输。
第二扩束装置EPE1可以包括衍射元件中第二输入元件DOE1b、第二扩束元件DOE2b、第二输出元件DOE3b。第二输入元件DOE1b通过衍射透过部分的输入光IN2形成第三传导光B1b。第二扩束元件DOE2b通过衍射第三传导光B1b形成第四传导光B2b。第二输出元件DOE3b通过衍射第四传导光B2b形成输出光束(B3bP1,B3bP2)。
第一扩束装置EPE1、第二扩束装置EPE2可以衍射扩展光。输出光OUT1中输出光束的宽度wOUT1可以远大于输入光IN1中输入光束的宽度wIN1。当输出光OUT1进入到观察者的眼睛时，观察者可以看到虚拟图像VIMG1。所显示的虚拟图像VIMG1可以代表输入图像IMG0。
第一扩束装置EPE1产生的第一输出光束可以透过第二扩束装置EPE2并传输到观察者的眼睛。总体输出光OUT1可以看成是第一输出光束和第二输出光束的组合。
传导光通过全内反射(TIR)被束缚在波导基板内。这里所说的传导光与波导光意思相同。
如图4a所示，第二波导基板SUB2的厚度tSUB2可以不同于第一波导基板SUB1的厚度tSUB1。第二波导基板SUB2上的第二输入元件DOE1b的折射率n2也可以不同于第一波导基板SUB1上的第一输入元件DOE1a的折射率n1。这里第一波导基板的厚度和第二波导基板的厚度的不同以及第一输入元件的折射率和第二输入元件的折射率的不同可以至少部分地补偿耦合效率函数ηEPE1(x,y,ψ,θ)的非均匀性。
第一输入元件DOE1a的光栅周期d1a可以与第二输入元件DOE1b的光栅周期d1b相等。
所述显示设备(500)可以包括：
光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)，
扩束装置叠层(STC1)，通过衍射扩展输入光(IN1)形成输出光(OUT1)，所述输出光(OUT1)包括一系列代表所述输入图像(IMG0)的输出光束(B3aP1,B3aP2,B3bP1,B3bP2)，
所述扩束装置叠层(STC1)包括一个第一扩束装置(EPE1)和一个第二扩束装置(EPE2)；
所述第一扩束装置(EPE1)包括一个第一输入元件(DOE1a)，用于将输入光(IN1)衍射输入到所述第一扩束装置(EPE1)的第一波导基板(SUB1)内，
所述第一扩束装置(EPE1)被设置为使得所述输入光(IN1)的一部分(IN2)透过所述第一扩束装置(EPE1)传输到所述第二扩束装置(EPE2)；
所述第二扩束装置(EPE2)包括一个第二输入元件(DOE1b)，用于将输入光(IN1)中透过所述第一扩束装置的部分(IN2)衍射输入到所述第二扩束装置(EPE2)的波导基板(SUB2)内；
其中，所述第一输入元件(DOE1a)的光栅周期(d1a)与所述第二输入元件(DOE1b)的光栅周期(d1b)相等。
所述显示设备(500)可以包括：
光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)；
扩束装置叠层(STC1)，包括第一扩束装置(EPE1)和第二扩束装置(EPE2)；
其中，所述第一扩束装置(EPE1)上各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与所述第二扩束装置(EPE2)上各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。
所述显示设备(500)可以包括：
光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)；
扩束装置叠层(STC1)，通过衍射扩展输入光(IN1)形成输出光(OUT1)，所述输出光(OUT1)包括一系列代表所述输入图像(IMG0)的输出光束(B3aP1,B3aP2,B3bP1,B3bP2)；
所述扩束装置叠层(STC1)包括一个第一扩束装置(EPE1)和一个第二扩束装置(EPE2)。
所述第一扩束装置(EPE1)包括第一衍射元件)组合(GRP1)，第一衍射元件组合(GRP1)包括第一输入元件DOE1a，第一扩束元件DOE2a，第一输出元件DOE3a，用于控制输出光束(B3aP1,B3aP2)的传播方向。
所述第二扩束装置(EPE2)包括第二衍射元件组合(GRP2)，第二衍射元件组合(GRP2)包括第二输入元件DOE1b,第二扩束元件DOE2b，第二输出元件DOE3b，用于控制输出光束(B3bP1,B3bP2)的传播方向。
所述第一扩束装置(EPE1)包括一个第一输入元件(DOE1a)，用于将输入光(IN1)衍射输入到所述第一扩束装置(EPE1)的波导基板(SUB1)内。
所述第一扩束装置(EPE1)被设置为使得所述输入光(IN1)的一部分(IN2)透过所述第一扩束装置(EPE1)传输到所述第二扩束装置(EPE2)。
所述第二扩束装置(EPE2)包括一个第二输入元件(DOE1b),用于将输入光(IN1)中透过所述第一扩束装置的部分(IN2)衍射输入到所述第二扩束装置(EPE2)的波导基板(SUB2)内；
其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与所述第二衍射元件组合(GRP2)中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。
相等的光栅周期(d1a,d1b)可以简化显示设备(500)的制造，因为第一扩 束装置EPE1和第二扩束装置EPE2可以通过同一个压印母版制作完成，如图6c和图6d所示，图6c为采用一个压印母版加工一种第一扩束装置的三维示意图，图6d为采用与图6c中相同的压印母版加工一种第二扩束装置的三维示意图。
相等的光栅周期(d1a,d1b)可以改善所显示虚拟图像VIMG1的均匀性，同时减少或消除第一扩束装置EPE1输出光束与第二扩束装置EPE2输出光束间传播方向不匹配的风险。
如图4b所示，第一波导基板SUB1和/或第二波导基板SUB2可以包括一层或多层材料(S11，S12，S21，S22)。例如，在一些实施例中，第一波导基板SUB1包括一层或多层材料(S11，S12，S21，S22)，在一些实施例中，第二波导基板SUB2包括一层或多层材料(S11，S12，S21，S22)，在一些实施例中，第一波导基板SUB1和第二波导基板SUB2均包括一层或多层材料(S11，S12，S21，S22)。
其中，需要说明的是，形成第一波导基板SUB1的材料和形成第二波导基板SUB2的材料可以相同也可以不相同，示例性的，在一些实施例中，即使第一波导基板SUB1由一种材料形成，第二波导基板SUB2也由一种材料形成，但是形成第一波导基板SUB1的材料和形成第二波导基板SUB2的材料可以不相同，例如，第一波导基板SUB1包括第一材料S11，第二波导基板SUB2包括第二材料S12。在一些实施例中，即使第一波导基板SUB1由多层材料形成，第二波导基板SUB2也由多层材料形成，但是形成第一波导基板SUB1的材料和形成第二波导基板SUB2的材料可以完全不相同，例如，第一波导基板SUB1包括第一材料S11和第二材料S12，第二波导基板SUB2包括第三材料S21和第四材料S22。可以理解的是，形成第一波导基板SUB1的材料和形成第二波导基板SUB2的材料也可以部分不相同，例如，第一波导基板SUB1包括第一材料S11和第二材料S12，第二波导基板SUB2包括第二材料S12和第四材料S22。在一些实施例中，第一波导基板SUB1由多层材料形成，第二波导基板SUB2由一层材料形成。在其他一些实施例中，第一波导基板SUB1由一层材料形成，第二波导基板SUB2由多层材料形成。通过将第一波导基板SUB1的组成材料和第二波导基板SUB2的组成材料根据实际情况进行组合设置，进而可以提供更合适的折射率，使得显示设备(500)可以适用于不同的应用场景，提高了显示设备(500)的可行性和实用性。在一些实施例中，第一扩束装置EPE1的第一波导基板SUB1和第二扩束装置EPE2的第二波导基板SUB2中的至少一个包括两层或多层材料(S11，S12，S21，S22)组成。采用两层或多层材料可以提供额外选择材料折射率(n11，n1，n21，n2)的自由度。额外的自用度可以用于提供更合适的耦合效率函数，例如ηEPE1(x,y,ψ,θ)和ηEPE2(x,y,ψ,θ)。
需要说明的是，多层材料(S11，S12，S21，S22)并不限于举例说明的第一材料S11、第二材料S12、第三材料S21和第四材料S22，可以是多于四种材料的组合，具体的设置在此不作具体的限定，可以根据实际情况进行设置。
第一波导基板SUB1可能包括两层或多层材料。第二波导基板SUB2也可能包括两层或多层材料。这里的材料层可以是透明的，以实现光束的传导。
第一透明基板S11可以被涂敷或旋涂一层透明材料以形成第一透明膜层S12。第一输入元件DOE1a可以被构造于所述第一透明膜层S12上。第一透明基板S11可以具有第三折射率n11。第一透明膜层S12可以具有第一折射率n1。
第二透明基板S21可以被涂敷或旋涂一层透明材料以形成第二透明膜层S22。第二输入元件DOE1b可以被构造于所述第二透明膜层S22上。第二透明基板S21可以具有第四折射率n21。第二透明膜层S12可以具有第二折射率n2。
所述显示装置500具有眼盒BOX1，如图2所示，眼盒BOX1代表观察者可以放置眼睛EYE1并看到所显示的虚拟图像VIMG1的空间。
请继续参阅图5a，图5a为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中平均亮度与两个波导基板厚度比值的关系曲线。如图5a显示了一种眼盒BOX1内的平均图像强度与厚度比tSUB2/tSUB1的关系曲线。三条曲线分别对应折射率n1＝1.5，n1＝1.7，n1＝1.9的情况。三种曲线对应的n2折射率都为1.9。
第一扩束装置(EPE1)上各衍射元件的光栅周期与第二扩束装置(EPE2)上各相应衍射元件的光栅周期相等。其中，第一扩束装置(EPE1)上各衍射元件中第一输入元件DOE1a的光栅周期为d1a，第一扩束元件DOE2a的光栅周期为d2a，第一输出元件DOE3a的光栅周期为d3a，第二扩束装置(EPE2)上各衍射元件中第二输入元件DOE1b的光栅周期为d1b，第二扩束元件DOE2b的光栅周期为d2b，第二输出元件DOE3b的光栅周期为d3b。即第一输入元件DOE1a的光栅周期d1a等于第二输入元件DOE1b的光栅周期d1b,第一扩束元件DOE2a的光栅周期d2a等于第二扩束元件DOE2b的光栅周期d2b，第一输出元件DOE3a的光栅周期d3a等于第二输出元件DOE3b的光栅周期d3b。在图5a示例中，输入图像IMG0是均匀的，即所有输入图像IMG0的图像点具有相等的亮度。
图5a中，点OP1对应折射率n1＝1.7，折射率n2＝1.9，以及厚度比tSUB2/tSUB1＝0.6的情况。Ref01作为对比，为显示设备只包括一个扩束装置EPE2时眼盒BOX1内的平均强度。点OP1情形显著高(+24％)于对比示例Ref01的平均亮度。标记a.u.代表任意单位。
当输入图像IMG0是均匀图像时，所述显示设备500可以被设置为以一足够程度的均匀性显示虚拟图像VIMG1。位置均匀性和/或角度均匀性可以被优化。所述显示装置500可以被设置为提供足够的位置显示均匀性；所述显示装置500还可以被设置为提供足够的角度显示均匀性。
当输入图像IMG0是均匀图像时(即输入图像上所有像素亮度相同时)，所述显示设备500可以提供在眼盒BOX1内不同方向上大体上均匀的方向强度分布，所述显示装置500还可以提供在眼盒BOX1内不同位置处大体上均匀的位置强度分布。
方向分布均匀意味着当输入图像时均匀图像时，不同方向传输的光束具有相等的强度。方向分布均匀意味着位于眼盒BOX1内的眼睛EYE1看到的虚拟图像VIMG1上不同像点P1和P2具有相同的亮度。方向分布均匀的程度可以用强度在不同角度处差异的标准差来衡量。更低的标准差表示更高的均匀性。
请继续参阅图5b，图5b为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中图像亮度角分布差异的标准差与两个波导基板厚度比值的关系。图5b显示了四种折射率值为n1＝1.4,n1＝1.5,n1＝1.7,n1＝1.9时，一种角度强度分布标准差与厚度比tSUB2/tSUB1的关系曲线。图5b中的标准差代表不同传播方向的输出光束间的强度差异。
在图5b中，第一扩束装置(EPE1)上的第一衍射元件组合中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与第二扩束装置(EPE2)上的第二衍射元件组合中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。即d1a＝d1b,d2a＝d2b,d3a＝d3b。并且，输入图像IMG0是均匀的，即所有输入图像IMG0的图像点具有相等的亮度。
Ref02作为对比，表示显示设备只包括一个扩束装置EPE2时眼盒BOX1内的角度强度标准差。点OP1情形对应的角度强度分布标准差显著低(30％)于对比示例Ref02的角度强度分布差异。
位置分布均匀意味着当输入图像是均匀图像时，眼睛EYE1在眼盒BOX1不同位置(x,y)接受到的输出光束强度相等。位置分布均匀意味着眼睛EYE1在眼盒BOX1内不同位置处看到的特定像点亮度相同。位置分布均匀的程度可以用强度在不同眼盒位置处观察到的亮度的标准差来衡量。更低的标准差表示更高的均匀性。
当输出光束B3aP1和B3bP1对应于输入图像IMG0上同一像点P1时，所显示像点(P1’)的亮度取决于第一扩束装置EPE1输出的第一输出光束B3aP1与第二扩束装置EPE2输出的第二输出光束B3bP1的强度和。输出光OUT1的位置分布可能大体上均匀，从而，当眼睛EYE1在眼盒内移动时，传输到眼睛EYE1的输出光束B3aP1和B3bP1的强度和独立于眼盒BOX1的位置(x,y)。
请继续参阅图5c，图5c为不同第一扩束装置波导基板折射率下，一种显示设备的眼盒中图像亮度位置分布差异的标准差与两个波导基板厚度比值的关系。图5c显示了当折射率分别为n1＝1.5,n1＝1.7,n1＝1.9时，一种位置强度分布标准差与厚度比值tSUB2/tSUB1的关系曲线。图5c中的标准差代表在眼盒BOX1不同位置(x,y)处观察到的图像强度差异。
在图5c中，第一扩束装置(EPE1)上的第一衍射元件组合中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与第二扩束装置(EPE2)上的第二衍射元件组合中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。即d1a＝d1b,d2a＝d2b,d3a＝d3b。并且，输入图像IMG0是均匀的，即所有输入图像IMG0的图像点具有相等的亮度。
Ref03作为对比，表示显示设备只包括一个扩束装置EPE2时眼盒BOX1内的位置强度标准差。点OP1情形对应的位置强度分布标准差大体上低(30％)于对比示例Ref03的位置强度分布差异。
可以根据所要达到的显示标准选择参数(tSUB1,tSUB2,n1,n2)的值。显示标准可以包括例如以下一条或多条要求：
角度空间分布的低标准差；
位置空间分布的低标准差；
不同颜色分布的低标准差；
显示设备500可以被设置为显示单色图像VIMG1。显示设备500可以被设置为显示例如绿色的图像VIMG1。在这种情况下，不需要优化图像的不同颜色间的分布均匀性。
显示设备500可以被设置为显示全彩图像VIMG1。例如，显示设备500可以显示RGB图像VIMG1，RGB图像包括红色(R)子图像、绿色(G)子图像、蓝色(B)子图像。在这种情况下，不同颜色分布的均匀性也可以作为优化参数(tSUB1,tSUB2,n1,n2)的目标。
图6a显示了一种第一扩束装置EPE1的示意图。第一扩束装置EPE1包括第一衍射元件组合GRP1，用于控制输出光束的传播方向。扩束装置EPE1包括第一衍射元件组合，这些衍射元件构建于第一波导基板SUB1上。所述第一衍射元件组合可以包括第一输入元件DOE1a、第一扩束元件DOE2a和第一输出元件DOE3a。
第一输入元件DOE1a具有光栅周期d1a。第一输入元件DOE1a可以由具有光栅周期d1a的衍射表面浮雕光栅G1a来实现。光栅G1a包括衍射特征F1a，其可以是微观脊、凹槽和/或突起。光栅G1a具有光栅矢量V1a。可以指定光栅矢量V1a的方向，例如第一角度β1a。输入元件DOE1a可以具有第一宽度w1a(在方向SX上)和第一高度h1a(在方向SY上)。
第一扩束元件DOE2a可以具有光栅周期d2a。第一扩束元件DOE2a可以由具有光栅周期d2a的衍射表面浮雕光栅G2a来实现。光栅G2a具有衍射特征F2a。光栅G2a具有光栅矢量V2a。光栅矢量V2a的方向可以由第二角度β2a指定。扩束元件DOE2a可以具有第二宽度w2a和第二高度h2a。
第一输出元件DOE3a可以具有光栅周期d3a。第一输出元件DOE3a可以由具有光栅周期d3a的衍射表面浮雕光栅G3a来实现。光栅G3a包括衍射特征F3a。光栅G3a具有光栅矢量V3a。光栅矢量V3a的方向可以由第三角度β3a指定。输出元件DOE3a可以具有第三宽度w3a和第三高度h3a。
光栅矢量的大小取决于衍射元件的衍射光栅的光栅周期，光栅矢量的方向取决于衍射光栅的取向。例如，光栅矢量V1a的大小取决于衍射元件DOE1a的衍射光栅G1a的光栅周期d1a，光栅矢量V1a的方向β1a取决于衍射光栅G1a的朝向。
第一扩束装置EPE1包括在光路中的第一衍射元件组合，第一衍射元件组合包括第一输入元件DOE1a、第一扩束元件DOE2a、第一输出元件DOE3a。第一输入元件DOE1a可以通过第一扩束装置EPE1的第一主表面接收输入光束B0P1、B0P2。第一扩束装置EPE1可以被设计为使光路中的衍射元件的光栅矢量的矢量和等于0(V1a+V2a+V3a＝0)，以保证由第一输出元件DOE3a提供的每个输出光束B3aP1,B3aP2分别与从光引擎ENG1获得的相应输入光束B0P1、B0P2平行。
图6b显示了一种第二扩束装置EPE2的示意图。第二扩束装置EPE2包括第二衍射元件组合GRP2，用于控制输出光束的传播方向。第二扩束装置EPE2包括第二衍射元件组合，这些衍射元件构建于第二波导基板SUB2上。所述第二衍射元件组合可以包括第二输入元件DOE1b、第二扩束元件DOE2b和第二输出元件DOE3b。
第一输入元件DOE1a和第二输入元件DOE1b可以执行相同的功能，即输入耦合。在这个意义上，第二输入元件DOE1b可以对应于第一输入元件DOE1a。第二扩束装置EPE2的第二输入元件DOE1b可以对应于第一扩束装置EPE1的第一输入元件DOE1a。第二扩束装置EPE2的第二扩束元件DOE2b可以对应于第一扩束装置EPE1的第一扩束元件DOE2a。第二扩束装置EPE2的第二输出元件DOE3b可以对应于第一扩束装置EPE1的第一输出元件DOE3a。
第二输入元件DOE1b可以具有光栅周期d1b。第二输入元件DOE1b可以由具有光栅周期d1b的衍射表面浮雕光栅G1b来实现。光栅G1b包括衍射特征F1b，其可以是例如微观脊、凹槽和/或突起。光栅G1b具有光栅矢量V1b。可以指定光栅矢量V1b的方向，例如角度β1b。输入元件DOE1b可以具有宽度w1b(在方向SX)和高度h1b(在方向SY)。
第二扩束元件DOE2b可以具有光栅周期d2b。第二扩束元件DOE2b可以由具有光栅周期d2b的衍射表面浮雕光栅G2b来实现。光栅G2b具有衍射特征F2b。光栅G2b具有光栅矢量V2b。光栅矢量V2b的方向可以由角度β2b指定。扩束元件DOE2b可以具有宽度w2b和高度h2b。
第二输出元件DOE3b可以具有光栅周期d3b。第二输出元件DOE3b可以由具有光栅周期d3b的衍射表面浮雕光栅G3b来实现。光栅G3b包括衍射特征F3b。光栅G3b具有光栅矢量V3b。光栅矢量V3b的方向可以由角度β3b指定。输出元件DOE3b可以具有宽度w3b和高度h3b。
第二扩束装置EPE2可以被设计为使光路中的衍射元件的光栅矢量的矢量和等于0(V1b+V2b+V3b＝0)，以保证由第二输出元件DOE3b提供的每个输出光束B3bP1,B3bP2分别与第二输入元件DOE1b接受并耦合的相应输入光束B0P1、B0P2平行。
第一衍射元件组合(GRP1)的每个元件(DOE1a、DOE2a、DOE3a)的形状可以与第二衍射元件组合(GPR2)的对应元素(DOE1b、DOE2b、DOE3b)的形状相同。 即第一输入元件DOE1a的形状与第二输入元件DOE1b的形状相同,第一扩束元件DOE2a的形状与第二扩束元件DOE2b的形状相同，第一输出元件DOE3a的形状与第二输出元件DOE3b的形状相同。
第一衍射元件组合(GRP1)的每个元素(DOE1a,DOE2a,DOE3a)的面积可以与第二衍射元件组合(GPR2)的对应元素(DOE1b,DOE2b,DOE3b)的面积相等，或者在一定精度范围内相等，例如精度优于1％。即第一输入元件DOE1a的面积与第二输入元件DOE1b的面积相等或者在一定精度范围内相等,第一扩束元件DOE2a的面积与第二扩束元件DOE2b的面积相等或者在一定精度范围内相等，第一输出元件DOE3a的面积与第二输出元件DOE3b的面积相等或者在一定精度范围内相等。
第一波导基板SUB1和第二波导基板SUB2包括平面波导核心层。在一个实施例中，第一波导基板SUB1和第二波导基板SUB2可以包括例如一层或多层包覆层、一层或多层保护层和/或一层或多层机械支撑层。厚度tSUB1、tSUB2可以指第一波导基板SUB1和第二波导基板SUB2的平面波导核心层的厚度。
第一波导基板SUB1和第二波导基板SUB2可以包括或基本上由透明固体材料组成。第一波导基板SUB1可以包括例如玻璃、聚碳酸酯或聚甲基丙烯酸甲酯(PMMA)。衍射光学元件可以通过模压、压花和/或蚀刻加工形成。衍射光学元件可以通过一个或多个表面衍射光栅实现。特别地，第一扩束装置EPE1的衍射光学元件可以是表面衍射光栅，其可以构造于波导基板SUB1的相同主表面(SRF1a或SRF1b)上。在同一主表面上构造元件可以简化生产。
可以通过使用光刻技术来生产衍射元件。例如，一种或多种压印工具可通过电子束光刻技术产生，并且衍射光栅可通过使用一种或多种压印工具形成。
如图6c和6d所示，第一扩束装置EPE1的第一输入元件DOE1a、第一扩束元件DOE2a、第一输出元件DOE3a可以通过压印工具TOOL1加工形成，并且第二扩束装置EPE2的衍射元件第二输入元件DOE1b、第二扩束元件DOE2b、第二输出元件DOE3b也可以通过相同的压印工具TOOL1加工形成。
使用相同的压印工具TOOL1来生产第一扩束装置EPE1和第二扩束装置EPE2可以简化生产。使用同一压印工具TOOL1制作第一扩束装置EPE1和第二扩束装置EPE2也可以确保第二扩束装置EPE2形成的出射光束方向与第一扩束装置EPE1形成的出射光束方向一致。
显示装置的制造方法可以包括使用相同的压印工具TOOL1形成第一输入元件DOE1a和第二输入元件DOE1b。
第一扩束装置EPE1的第一衍射元件组合GRP1(DOE1a、DOE2a、DOE3a)和第二扩束装置EPE2的第二衍射元件组合GRP2(DOE1b、DOE2b、DOE3b)可以通过使用相同的压印工具TOOL1来形成。
工具TOOL1可用作模具或压印模具，用于形成衍射元件的表面浮雕光栅。元件的衍射特征可以通过在工具TOOL1和背衬COU1之间压制波导板SUB1或 SUB2来形成。背衬COU1可以在压制过程中支撑第一波导基板SUB1或第二波导基板SUB2。第一波导基板SUB1和第二波导基板SUB2可以通过预热以便于形成衍射微结构。第一波导基板SUB1和第二波导基板SUB2的涂层可以是例如通过固化以使形成的衍射微结构更加牢固。
工具TOOL1可以包括用于形成第一输入元件DOE1a和第二输入元件DOE1b的第一区域RF1。工具TOOL1可以包括用于形成第一扩束元件DOE2a和第二扩束元件DOE2b的第二区域RF2。工具TOOL1可以包括用于形成第一输出元件DOE3a和第二输出元件DOE3b的第三区域RF3。第一区域RF1、第二区域RF2和第三区域RF3可以包括用于形成第一扩束装置EPE1和第二扩束装置EPE2的衍射元件的微观突起。
如图7a至7e所示，图7a到图7e为一种光引擎生成输入光束的三维示意图。光学引擎ENG1可以形成输入光IN1，其代表输入图像IMG0。光学引擎ENG1可以形成输入图像IMG0并且可以将输入图像IMG0转换为输入光IN1的多个光束B0P1、B0P2。输入光IN1可以包括表示输入图像IMG0的多个输入光束(B0P1，B0P2)。光学引擎ENG1可包括显示元件DISP1以产生输入图像IMG0。输入图像IMG0可以包括排列成二维阵列的多个图像点P1、P2。光学引擎ENG1可以包括准直光学器件LNS1以从输入图像IMG0的图像点P1、P2形成多个输入光束(B0P1、B0P2)。
输入图像IMG0可以包括一个中心点P0和四个角点P1、P2、P3、P4。P1可以表示左上角点。P2可以表示右上角点。P3可以表示左下角点。P4可以表示右下角点。输入图像IMG0可以包括例如图形字符“F”、“G”和“H”。输入图像IMG0可以表示显示的信息。
输入图像IMG0可以是单色图像，也可以是多色图像。输入图像IMG0可以是例如RGB图像，其可以包括红色(R)部分图像、绿色(G)部分图像和蓝色(B)部分图像。输入图像IMG0可以通过例如调制激光或调制从一个或多个发光二极管获得的光而形成。
光学引擎ENG1可以提供输入光IN1，其可以包括多个基本准直的光束B0P0,B0P1,B0P2,B0P3,B0P4。中心点P0的光B0P0可以在光学引擎ENG1的光轴AX0的方向上传播。
参考图7f，所显示的虚像VIMG1可以具有中心点P0'和四个角点P1'、P2'、P3'、P4'。输入光IN1可以包括对应于输入图像IMG0的点P0、P1、P2、P3、P4的多个部分的光束。扩束装置EPE1、EPE2可以通过例如对输入图像IMG0的P0点的光进行衍射和引导，形成所显示的虚拟图像VIMG1的点P0'。扩束装置EPE1可以形成点P1'、P2'、P3'、P4'，例如通过分别衍射和引导点P1、P2、P3、P4的光实现。
输出光OUT1可能包括一系列输出光束B3aP0,B3aP1,B3aP2,B3aP3,B3aP4,B3bP0,B3bP1,B3bP2,B3bP3,B3bP4。
第一扩束装置EPE1的第一输出元件DOE3a可以通过将传导光衍射出波导板SUB1来形成输出光束B3aP0,B3aP1,B3aP2,B3aP3,B3aP4。
第二扩束装置EPE1的第二输出元件DOE3b可以通过将传导光衍射出波导板SUB2来形成输出光束B3bP0,B3bP1,B3bP2,B3bP3,B3bP4。
输出光OUT1可以看成为由两个或更多个第一扩束装置EPE1、第二扩束装置EPE2提供的输出光束的组合。
输出光束B3aP0和B3bP0可以由输入光束B0P0的光形成，其对应于输入图像IMG0的图像点P0。显示设备500可以被设置成使得输出光束B3aP0的方向平行于输出光束B3bP0的方向。输出光束B3aP0和B3bP0可能看起来起源于虚像VIMG1的点P0'。
输出光束B3aP1,B3bP1可以相互平行，其可以对应于输入图像IMG0的像点P1，也可以对应于虚像VIMG1的像点P1'。
输出光束B3aP2,B3bP2可以相互平行，其可以对应于输入图像IMG0的像点P2，也可以对应于虚像VIMG1的像点P2'。
输出光束B3aP3,B3bP3可以相互平行，其可以对应于输入图像IMG0的像点P3，也可以对应于虚像VIMG1的像点P3'。
输出光束B3aP4,B3bP4可以相互平行，可以对应于输入图像IMG0的像点P4，也可以对应于虚像VIMG1的像点P4'。
如图7g和图7h所示，图7g为一种所显示的虚拟图像的角度宽度示意图；图7h为一种所显示的虚拟图像的角度高度示意图。所显示的虚像VIMG1的角宽为△ψVIMG1，角高为△θVIMG1。
所显示的虚拟图像VIMG1可以具有第一角点P1'，在例如图像VIMG1的左侧，以及第二个角点P2'在例如图像VIMG1的右侧。虚像VIMG1的角宽度△ψVIMG1可以等于输出光束B3aP和B3aP2传播方向之间的水平夹角。
显示的虚像VIMG1可以具有上角点P1'和下角点P3'。虚像VIMG1的角高△θVIMG1可以等于输出光束B3aP1和B3aP3方向之间的垂直角。
可以指定光束的方向，例如通过方向角ψ和θ可以表示光束的方向和参考平面REF1之间的角度。参考平面REF1可以定义为例如方向SZ和SY所在平面。角度θ可以表示光束的方向和参考平面REF2之间的角度。角度ψB3a,P1和角度θB3a,P1表示输出光束B3aP1的方向，该方向对应于像点P1。
参考平面REF2可以定义为例如方向SZ和SX所在平面。像点P1发出的光束方向可以由方向角θB3,P1,ψB3,P1表示。
输入图像IMG0可以表示显示的信息。输入图像IMG0可以表示例如图形和/或文本。输入图像IMG0可以表示例如视频。光引擎ENG1可以被布置成生成静止图像和/或视频。光引擎ENG1可以从数字图像生成真实的主图像IMG0。光引擎ENG1可以接收一个或多个数字图像，例如从互联网服务器或智能手机。
显示器DISP1可以包括显示像素的二维阵列。显示器DISP1可以包括发光 显示像素的二维阵列。光引擎ENG1可以包括例如一个或多个发光二极管(LED)。显示器DISP1可以包括例如一个或多个微显示成像器，例如硅上液晶(LCOS)、液晶显示器(LCD)、数字微镜器件(DMD)。显示器DISP1可以生成输入图像IMG0，例如分辨率为1280×720(HD)。显示器DISP1可以生成输入图像IMG0，例如分辨率为1920×1080(全高清)。显示器DISP1可以生成输入图像IMG0，例如分辨率为3840×2160(4K UHD)。输入图像IMG0可以包括多个图像点P0、P1、P2…等等。光引擎ENG1可以包括准直光学器件LNS1以从每个图像像素形成光束。引擎ENG1可以包括准直光学器件LNS1以从图像点的光形成基本准直的光束。
在一个实施例中，第一扩束装置EPE1、第二扩束装置EPE2可以仅由两个衍射元件实现。第一扩束装置EPE1可以包括第一输入元件DOE1a以形成第一传导光B1a，其中第一输出元件DOE3a可以被布置为通过将第一传导光B1a衍射出第一波导基板SUB1来形成输出光OUT1。第一扩束装置EPE1可以在没有第一扩束元件DOE2a的情况下实现。第一扩束装置EPE1可以由两个衍射元件即第一输入元件DOE1a和第一输出元件DOE3a来实现。类似地，第二扩束装置EPE2可以由第二输入元件DOE1b和第二输出元件DOE3b实现，而没有第二扩束元件DOE2b。第二输出元件DOE3b可以将传导光B1b衍射出第二波导基板SUB2。
在另一个实施例中，第一扩束装置EPE1可以包括四个衍射元件，用于控制输出光束的方向。这四个元件可以形成一条光束传输光路，实现光束从第一输入元件DOE1a传输到第一输出元件DOE3a。第一输入元件DOE1a可以通过衍射输入光IN1来形成传导光B1a。第一扩束元件DOE2a可以通过衍射传导光B1a来形成扩展传导光B2a。附加扩束元件可以通过衍射扩展传导光B2a来形成附加传导光。第一输出元件DOE3a可以通过将附加传导光衍射出波导板SUB1来形成输出光。类似的，第二扩束装置EPE2也可以包括四个衍射元件，用于控制输出光束的方向。
以上已经描述了本申请的各实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择，旨在最好地解释各实施例的原理、实际应用或对市场中的技术的改进，或者使本技术领域的其它普通技术人员能理解本文披露的各实施例。
本申请实施例提供一种显示设备(500)，包括：
光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)；
扩束装置叠层(STC1)，通过衍射扩展所述输入光(IN1)形成输出光(OUT1)，所述输出光(OUT1)包括一系列代表所述输入图像(IMG0)的输出光束 (B3aP1,B3aP2,B3bP1,B3bP2)；
所述扩束装置叠层(STC1)包括一个第一扩束装置(EPE1)和一个第二扩束装置(EPE2)；
所述第一扩束装置(EPE1)包括第一衍射元件组合(GRP1)，用于控制第一输出光束(B3aP1,B3aP2)的传播方向；
所述第二扩束装置(EPE2)包括第二衍射元件组合(GRP2)，用于控制第二输出光束(B3bP1,B3bP2)的传播方向；
所述第一扩束装置(EPE1)包括一个第一输入元件(DOE1a)，用于将所述输入光(IN1)衍射输入到所述第一扩束装置(EPE1)的第一波导基板(SUB1)内；
所述第一扩束装置(EPE1)被设置为使部分所述输入光(IN1)透过所述第一扩束装置(EPE1)传输到所述第二扩束装置(EPE2)；
所述第二扩束装置(EPE2)包括一个第二输入元件(DOE1b)，用于将透过所述第一扩束装置的部分所述输入光(IN1)衍射输入到所述第二扩束装置(EPE2)的第二波导基板(SUB2)内；
其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与所述第二衍射元件组合(GRP2)中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。
其中，所述第一输入元件(DOE1a)的折射率(n1)与所述第二输入元件(DOE1b)的折射率(n2)不同。
其中，所述第一扩束装置(EPE1)的波导基板(SUB1)的厚度(tSUB1)与所述第二扩束装置(EPE2)的波导基板(SUB2)的厚度(tSUB2)不同。
其中，所述第一波导基板(SUB1)和所述第二波导基板(SUB2)中的至少一个包括两种或两种以上的材料(S11，S12)。
其中，形成所述第一波导基板(SUB1)的材料和形成第二波导基板(SUB2)的材料相同。
其中，所述第一波导基板(SUB1)的材料(S11，S12)为透明材料，以实现光束的传导。
其中，所述第一波导基板(SUB1)包括玻璃、聚碳酸酯或聚甲基丙烯酸甲酯(PMMA)中的一种或组合。
其中，选择所述第一波导基板(SUB1)的厚度(tSUB1)和所述第二波导基板(SUB2)的厚度(tSUB2)；和/或
选择所述第一输入元件(DOE1a)的折射率(n1)和所述第二输入元件(DOE1b)的折射率(n2)，使得所述第二扩束装置(EPE2)的输出光至少部分地补偿所述第一扩束装置(EPE1)的输出光，以使得所述输出光(OUT1)更加均匀。
其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a，DOE2a, DOE3a)的形状与所述第二衍射元件组合(GRP2)中相应衍射元件(DOE1b，DOE2b,DOE3b)的形状相同。
其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a，DOE2a,DOE3a)的面积与所述第二衍射元件组合(GRP2)中相应衍射元件(DOE1b，DOE2b,DOE3b)的面积差异小于1％。
其中，所述第一衍射元件组合(GRP1)包括：
第一输入元件(DOE1a)，用于将所述输入光(IN1)衍射输入所述第一波导基板(SUB1)，以形成在所述第一波导基板(SUB1)内传输的第一传导光(B1a)；
第一扩束元件(DOE2a)，用于衍射所述第一传导光(B1a)形成第二传导光(B2a)；以及
第一输出元件(DOE3a)，用于将所述第二传导光(B2a)衍射输出所述第一波导基板(SUB1)，形成输出光(OUT1)；
所述第二衍射元件组合(GRP2)包括：
第二输入元件(DOE1b)，用于将透过所述第一衍射波导(EPE1)的部分所述输入光(IN1)衍射输入所述第二波导基板(SUB2)，以形成在所述第二波导基板(SUB2)内传输的第三传导光(B1b)；
第二扩束元件(DOE2b)，用于衍射所述第三传导光(B1b)形成第四传导光(B2b)；以及
第二输出元件(DOE3b)，用于将所述第四传导光(B2b)衍射输出所述第二波导基板(SUB2)，形成输出光(OUT1)。
其中，第一波导基板(SUB1)和第二波导基板(SUB2)包括平面波导核心层，所述第一波导基板(SUB1)的厚度等于所述第一波导基板(SUB1)的面波导核心层的厚度，所述第二波导基板(SUB2)的厚度等于所述第二波导基板(SUB2)的平面波导核心层的厚度。
其中，所述第一波导基板(SUB1)包括一层或多层包覆层、一层或多层保护层和/或一层或多层机械支撑层。
其中，所述第二波导基板(SUB2)包括一层或多层包覆层、一层或多层保护层和/或一层或多层机械支撑层。
其中，所述光引擎(ENG1)包括一个显示屏(DISP1)以及准直透镜组(LNS1)，所述显示屏(DISP1)被设置为显示输入图像(IMG0)，所述准直透镜组(LNS1)用于准直图像像点。
本申请实施例还提供一种虚拟图像显示方法，应用于显示设备(500)，所述显示设备为根据上述所述的显示设备(500)，所述显示方法包括：
形成输入光(IN1)，所述输入光包括对应输入图像(IMG0)上不同图像点(P1，P2)的光束(B0P1,B0P2)；
采用所述扩束装置叠层(STC1)衍射扩展所述输入光(IN1)以形成输出光(OUT1)。
本申请实施例还提供一种显示设备(500)的制造方法，所述制造方法用于制造如上述所述的显示设备(500)，所述制造方法包括：
采用同一个压印母版(TOOL1)制作所述第一输入元件(DOE1a)和所述第二输入元件(DOE1b)。
其中，所述制造方法还包括采用同一个压印母版(TOOL1)制作所述第一衍射元件组合(GRP1)和所述第二衍射元件组合(GRP2)。
其中，所述制造方法还包括：
在所述压印母版(TOOL1)和背衬(COU1)之间压制波导板(SUB1)或(SUB2)以形成元件的衍射特征。
其中，所述制造方法还包括：
通过预热以使所述第一波导基板(SUB1)和所述第二波导基板(SUB2)形成衍射微结构。

Claims (20)

  1. 一种显示设备(500)，其中，包括：
    光引擎(ENG1)，用于形成输入光(IN1)，所述输入光包括一系列代表输入图像(IMG0)的输入光束(B0P1,B0P2)；
    扩束装置叠层(STC1)，通过衍射扩展所述输入光(IN1)形成输出光(OUT1)，所述输出光(OUT1)包括一系列代表所述输入图像(IMG0)的输出光束(B3aP1,B3aP2,B3bP1,B3bP2)；
    所述扩束装置叠层(STC1)包括一个第一扩束装置(EPE1)和一个第二扩束装置(EPE2)；
    所述第一扩束装置(EPE1)包括第一衍射元件组合(GRP1)，用于控制第一输出光束(B3aP1,B3aP2)的传播方向；
    所述第二扩束装置(EPE2)包括第二衍射元件组合(GRP2)，用于控制第二输出光束(B3bP1,B3bP2)的传播方向；
    所述第一扩束装置(EPE1)包括一个第一输入元件(DOE1a)，用于将所述输入光(IN1)衍射输入到所述第一扩束装置(EPE1)的第一波导基板(SUB1)内；
    所述第一扩束装置(EPE1)被设置为使部分所述输入光(IN1)透过所述第一扩束装置(EPE1)传输到所述第二扩束装置(EPE2)；
    所述第二扩束装置(EPE2)包括一个第二输入元件(DOE1b)，用于将透过所述第一扩束装置的部分所述输入光(IN1)衍射输入到所述第二扩束装置(EPE2)的第二波导基板(SUB2)内；
    其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a,DOE2a,DOE3a)的光栅周期(d1a,d2a,d3a)与所述第二衍射元件组合(GRP2)中各相应衍射元件(DOE1b,DOE2b,DOE3b)的光栅周期(d1b,d2b,d3b)相等。
  2. 根据权利要求1所述的显示设备(500)，其中，所述第一输入元件(DOE1a)的折射率(n1)与所述第二输入元件(DOE1b)的折射率(n2)不同。
  3. 根据权利要求1所述的显示设备(500)，其中，所述第一扩束装置(EPE1)的波导基板(SUB1)的厚度(tSUB1)与所述第二扩束装置(EPE2)的波导基板(SUB2)的厚度(tSUB2)不同。
  4. 根据权利要求1所述的显示设备(500)，其中，所述第一波导基板(SUB1)和所述第二波导基板(SUB2)中的至少一个包括两种或两种以上的材料(S11，S12)。
  5. 根据权利要求4所述的显示设备(500)，其中，形成所述第一波导基板(SUB1)的材料和形成第二波导基板(SUB2)的材料相同。
  6. 根据权利要求4所述的显示设备(500)，其中，所述第一波导基板(SUB1)的材料(S11，S12)为透明材料，以实现光束的传导。
  7. 根据权利要求4所述的显示设备(500)，其中，所述第一波导基板(SUB1) 包括玻璃、聚碳酸酯或聚甲基丙烯酸甲酯(PMMA)中的一种或组合。
  8. 根据权利要求1所述的显示设备(500)，其中，选择所述第一波导基板(SUB1)的厚度(tSUB1)和所述第二波导基板(SUB2)的厚度(tSUB2)；和/或
    选择所述第一输入元件(DOE1a)的折射率(n1)和所述第二输入元件(DOE1b)的折射率(n2)，使得所述第二扩束装置(EPE2)的输出光至少部分地补偿所述第一扩束装置(EPE1)的输出光，以使得所述输出光(OUT1)更加均匀。
  9. 根据权利要求1所述的显示设备(500)，其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a，DOE2a,DOE3a)的形状与所述第二衍射元件组合(GRP2)中相应衍射元件(DOE1b，DOE2b,DOE3b)的形状相同。
  10. 根据权利要求1所述的显示设备(500)，其中，所述第一衍射元件组合(GRP1)中各衍射元件(DOE1a，DOE2a,DOE3a)的面积与所述第二衍射元件组合(GRP2)中相应衍射元件(DOE1b，DOE2b,DOE3b)的面积差异小于1％。
  11. 根据权利要求1所述的显示设备(500)，其中，所述第一衍射元件组合(GRP1)包括：
    第一输入元件(DOE1a)，用于将所述输入光(IN1)衍射输入所述第一波导基板(SUB1)，以形成在所述第一波导基板(SUB1)内传输的第一传导光(B1a)；
    第一扩束元件(DOE2a)，用于衍射所述第一传导光(B1a)形成第二传导光(B2a)；以及
    第一输出元件(DOE3a)，用于将所述第二传导光(B2a)衍射输出所述第一波导基板(SUB1)，形成输出光(OUT1)；
    所述第二衍射元件组合(GRP2)包括：
    第二输入元件(DOE1b)，用于将透过所述第一衍射波导(EPE1)的部分所述输入光(IN1)衍射输入所述第二波导基板(SUB2)，以形成在所述第二波导基板(SUB2)内传输的第三传导光(B1b)；
    第二扩束元件(DOE2b)，用于衍射所述第三传导光(B1b)形成第四传导光(B2b)；以及
    第二输出元件(DOE3b)，用于将所述第四传导光(B2b)衍射输出所述第二波导基板(SUB2)，形成输出光(OUT1)。
  12. 根据权利要求1所述的显示设备(500)，其中，第一波导基板(SUB1)和第二波导基板(SUB2)包括平面波导核心层，所述第一波导基板(SUB1)的厚度等于所述第一波导基板(SUB1)的面波导核心层的厚度，所述第二波导基板(SUB2)的厚度等于所述第二波导基板(SUB2)的平面波导核心层的厚度。
  13. 根据权利要求1所述的显示设备(500)，其中，所述第一波导基板(SUB1)包括一层或多层包覆层、一层或多层保护层和/或一层或多层机械支撑层。
  14. 根据权利要求1所述的显示设备(500)，其中，所述第二波导基板(SUB2) 包括一层或多层包覆层、一层或多层保护层和/或一层或多层机械支撑层。
  15. 根据权利要求1所述的显示设备(500)，其中，所述光引擎(ENG1)包括一个显示屏(DISP1)以及准直透镜组(LNS1)，所述显示屏(DISP1)被设置为显示输入图像(IMG0)，所述准直透镜组(LNS1)用于准直图像像点。
  16. 一种虚拟图像显示方法，其中，应用于显示设备(500)，所述显示设备为根据权利要求1所述的显示设备(500)，所述显示方法包括：
    形成输入光(IN1)，所述输入光包括对应输入图像(IMG0)上不同图像点(P1，P2)的光束(B0P1,B0P2)；
    采用所述扩束装置叠层(STC1)衍射扩展所述输入光(IN1)以形成输出光(OUT1)。
  17. 一种显示设备(500)的制造方法，其中，所述制造方法用于制造如权利要求1所述的显示设备(500)，所述制造方法包括：
    采用同一个压印母版(TOOL1)制作所述第一输入元件(DOE1a)和所述第二输入元件(DOE1b)。
  18. 根据权利要求17所述的制造方法，其中，所述制造方法还包括采用同一个压印母版(TOOL1)制作所述第一衍射元件组合(GRP1)和所述第二衍射元件组合(GRP2)。
  19. 根据权利要求17所述的制造方法，其中，所述制造方法还包括：
    在所述压印母版(TOOL1)和背衬(COU1)之间压制波导板(SUB1)或(SUB2)以形成元件的衍射特征。
  20. 根据权利要求17所述的制造方法，其中，所述制造方法还包括：
    通过预热以使所述第一波导基板(SUB1)和所述第二波导基板(SUB2)形成衍射微结构。
PCT/CN2023/087969 2022-10-12 2023-04-13 显示设备、虚拟图像显示方法和显示设备的制造方法 WO2024077907A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202211248634.XA CN115480413A (zh) 2022-10-12 2022-10-12 显示设备、虚拟图像显示方法和显示设备的制造方法
CN202211248634.X 2022-10-12

Publications (1)

Publication Number Publication Date
WO2024077907A1 true WO2024077907A1 (zh) 2024-04-18

Family

ID=84396312

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2023/087969 WO2024077907A1 (zh) 2022-10-12 2023-04-13 显示设备、虚拟图像显示方法和显示设备的制造方法

Country Status (3)

Country Link
US (1) US20240126093A1 (zh)
CN (1) CN115480413A (zh)
WO (1) WO2024077907A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115480413A (zh) * 2022-10-12 2022-12-16 深圳市光途显示科技有限公司 显示设备、虚拟图像显示方法和显示设备的制造方法

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20170299860A1 (en) * 2016-04-13 2017-10-19 Richard Andrew Wall Waveguide-Based Displays With Exit Pupil Expander
CN208721896U (zh) * 2018-08-29 2019-04-09 深圳珑璟光电技术有限公司 一种近眼显示装置
EP3588150A1 (en) * 2018-06-29 2020-01-01 Thomson Licensing An optical device comprising multi-layer waveguides
CN210243962U (zh) * 2018-05-17 2020-04-03 威福光学有限公司 用于增强现实显示器的光学结构及增强现实显示器
CN210835313U (zh) * 2019-08-22 2020-06-23 苏州苏大维格科技集团股份有限公司 全息衍射波导镜片、波导镜片组及增强现实彩色显示装置
CN112415656A (zh) * 2019-08-22 2021-02-26 苏州苏大维格科技集团股份有限公司 一种全息衍射波导镜片及增强现实彩色显示装置
CN113168003A (zh) * 2018-11-30 2021-07-23 奇跃公司 用于增强现实设备中的高效目镜的方法和系统
CN114185131A (zh) * 2021-12-14 2022-03-15 中国人民解放军海军工程大学 防止隐私泄露的衍射光波导装置和增强现实显示设备
CN114859554A (zh) * 2022-04-02 2022-08-05 江西凤凰光学科技有限公司 一种多层衍射光波导装置
CN115145042A (zh) * 2022-09-06 2022-10-04 北京亮亮视野科技有限公司 衍射波导器件和近眼显示装置
CN115373062A (zh) * 2021-05-17 2022-11-22 上海鲲游科技有限公司 衍射光波导装置及其方法
CN115480413A (zh) * 2022-10-12 2022-12-16 深圳市光途显示科技有限公司 显示设备、虚拟图像显示方法和显示设备的制造方法

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017180408A1 (en) * 2016-04-13 2017-10-19 Microsoft Technology Licensing, Llc Waveguide-based displays with exit pupil expander
US20170299860A1 (en) * 2016-04-13 2017-10-19 Richard Andrew Wall Waveguide-Based Displays With Exit Pupil Expander
CN210243962U (zh) * 2018-05-17 2020-04-03 威福光学有限公司 用于增强现实显示器的光学结构及增强现实显示器
CN112654900A (zh) * 2018-06-29 2021-04-13 交互数字Ce专利控股公司 包括多层波导的光学设备
EP3588150A1 (en) * 2018-06-29 2020-01-01 Thomson Licensing An optical device comprising multi-layer waveguides
CN208721896U (zh) * 2018-08-29 2019-04-09 深圳珑璟光电技术有限公司 一种近眼显示装置
CN113168003A (zh) * 2018-11-30 2021-07-23 奇跃公司 用于增强现实设备中的高效目镜的方法和系统
CN112415656A (zh) * 2019-08-22 2021-02-26 苏州苏大维格科技集团股份有限公司 一种全息衍射波导镜片及增强现实彩色显示装置
CN210835313U (zh) * 2019-08-22 2020-06-23 苏州苏大维格科技集团股份有限公司 全息衍射波导镜片、波导镜片组及增强现实彩色显示装置
CN115373062A (zh) * 2021-05-17 2022-11-22 上海鲲游科技有限公司 衍射光波导装置及其方法
CN114185131A (zh) * 2021-12-14 2022-03-15 中国人民解放军海军工程大学 防止隐私泄露的衍射光波导装置和增强现实显示设备
CN114859554A (zh) * 2022-04-02 2022-08-05 江西凤凰光学科技有限公司 一种多层衍射光波导装置
CN115145042A (zh) * 2022-09-06 2022-10-04 北京亮亮视野科技有限公司 衍射波导器件和近眼显示装置
CN115480413A (zh) * 2022-10-12 2022-12-16 深圳市光途显示科技有限公司 显示设备、虚拟图像显示方法和显示设备的制造方法

Also Published As

Publication number Publication date
US20240126093A1 (en) 2024-04-18
CN115480413A (zh) 2022-12-16

Similar Documents

Publication Publication Date Title
CN112817153B (zh) 一种大视场角的光学扩瞳装置、显示装置及方法
US10698149B2 (en) Display for two-dimensional and/or three-dimensional images
EP3590003B1 (en) Metasurface optical coupling elements for a display waveguide
JP6633087B2 (ja) ３次元（３ｄ）電子ディスプレイ
CN110809730B (zh) 在一块板上支持红色、绿色和蓝色的大视场波导
TWI697693B (zh) 多光束元件式近眼顯示器、系統、與方法
US10459140B2 (en) Image display device
WO2018072514A1 (zh) 显示装置及图像显示方法
US8797620B2 (en) Autostereoscopic display assembly based on digital semiplanar holography
US11789261B2 (en) Optical expander device for displaying wide color image, display device thereof, and method for outputting light and displaying an image
WO2023029360A1 (zh) 光学扩瞳装置、显示装置、光束扩展方法及图像显示方法
US10613335B2 (en) Light guide plate made of lead-free glass having a high refractive index and image display device using a light guide plate
WO2024077907A1 (zh) 显示设备、虚拟图像显示方法和显示设备的制造方法
JP2020079904A (ja) 導光板および画像表示装置
EP3781980A1 (en) Electronic device with multi-element display illumination system
CN215813430U (zh) 光波导系统和近眼显示器
WO2021196370A1 (zh) 以子像素为显示单元的单目多视图显示方法
WO2024022088A1 (zh) 一种显示设备和显示虚拟图像的方法
US20220035159A1 (en) Waveguide-based projector
WO2023169502A1 (zh) 一种大视场角的光学扩瞳装置、显示装置及方法
WO2020047150A1 (en) Dynamic incoupling gratings in imaging systems
WO2021140716A1 (ja) 画像表示素子、画像表示装置および画像表示方法
WO2022124024A1 (ja) 画像表示装置および画像表示方法
EP4174559A1 (en) Display apparatus providing expanded eye box
CN220154676U (zh) 光波导片和显示系统

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23876119

Country of ref document: EP

Kind code of ref document: A1