WO2023246192A1 - 大区域显示装置、车用抬头显示设备及虚拟图像显示方法 - Google Patents

大区域显示装置、车用抬头显示设备及虚拟图像显示方法 Download PDF

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Publication number
WO2023246192A1
WO2023246192A1 PCT/CN2023/081656 CN2023081656W WO2023246192A1 WO 2023246192 A1 WO2023246192 A1 WO 2023246192A1 CN 2023081656 W CN2023081656 W CN 2023081656W WO 2023246192 A1 WO2023246192 A1 WO 2023246192A1
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Prior art keywords
input
coupling element
grating
vector
light
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PCT/CN2023/081656
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English (en)
French (fr)
Inventor
朱以胜
利沃拉 塔帕尼卡列沃
蒋厚强
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深圳七泽技术合伙企业(有限合伙)
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Publication of WO2023246192A1 publication Critical patent/WO2023246192A1/zh

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0013—Means for improving the coupling-in of light from the light source into the light guide
    • G02B6/0015—Means for improving the coupling-in of light from the light source into the light guide provided on the surface of the light guide or in the bulk of it
    • G02B6/0016—Grooves, prisms, gratings, scattering particles or rough surfaces
    • 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
    • G02B27/44—Grating systems; Zone plate systems
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R1/00—Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/0808—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more diffracting elements
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/0101—Head-up displays characterised by optical features
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • 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
    • G02B27/42—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
    • G02B27/4222—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 in projection exposure systems, e.g. photolithographic systems
    • 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
    • G02B27/4272—Diffraction optics, i.e. systems including a diffractive element being designed for providing a diffractive effect having plural diffractive elements positioned sequentially along the optical path
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K2360/00—Indexing scheme associated with groups B60K35/00 or B60K37/00 relating to details of instruments or dashboards
    • B60K2360/20—Optical features of instruments
    • B60K2360/33—Illumination features
    • B60K2360/343—Illumination of matrix displays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/20—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor
    • B60K35/21—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays
    • B60K35/23—Head-up displays [HUD]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
    • B60R2300/00—Details of viewing arrangements using cameras and displays, specially adapted for use in a vehicle
    • B60R2300/30—Details of viewing arrangements using cameras and displays, specially adapted for use in a vehicle characterised by the type of image processing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2200/00—Type of vehicle
    • B60Y2200/10—Road Vehicles
    • B60Y2200/11—Passenger cars; Automobiles

Definitions

  • the present invention relates to the field of optical display technology, and in particular to a large-area display device, a vehicle head-up display device and a virtual image display method.
  • Virtual display devices in the prior art generally include a light engine and a diffractive optical waveguide module.
  • the light engine generates an input beam and carries image information to propagate in different directions. The propagation direction corresponds to different pixels of the microdisplay in the light engine.
  • the diffraction light waveguide module expands the input light and illuminates the user's eyes through the exit pupil area, allowing the user to observe the image displayed in the microdisplay on the exit pupil plane.
  • the Eye Box refers to the movable space where the pupil can obtain complete image information. If the pupil falls outside the Eye Box area, the expanded beam will not be able to enter the eyeball, and the displayed image will not be observed.
  • the size of the Eye Box is limited by the size of the external coupling element (exit pupil area) of the diffractive optical waveguide module.
  • Embodiments of the present invention provide a large-area display device, a vehicle head-up display device, and a virtual image display method, aiming to realize large-area display of images while reducing the manufacturing difficulty and cost of the display device.
  • embodiments of the present invention provide a large-area display device, including a light engine for generating an input image and converting the input image into input light, an image expander for expanding the input light, and a rotating device for rotating the input image.
  • the image expander is a driving device for producing a large area display;
  • the image expander includes an optical waveguide plate, which is provided with an input coupling element for coupling input light to the optical waveguide plate and forming at least one waveguide light in a grating direction, and an input coupling element for coupling the waveguide light. a first main output coupling element and a second main output coupling element of the output;
  • the input coupling element has a first input grating vector and a second input grating vector; the first main output coupling element has a first output grating vector, and the second main output coupling element has a second main output grating vector; wherein , the vector sum of the first input grating vector and the first output grating vector is zero, the vector sum of the second input grating vector and the second output grating vector is zero, the first input grating vector of the input coupling element and the The angle between the two input grating vectors is 60° ⁇ 120°.
  • embodiments of the present invention provide a vehicle head-up display device, including the large-area display device described in the first aspect.
  • embodiments of the present invention provide a virtual image display method, which is implemented using the large-area display device described in the first aspect.
  • Embodiments of the present invention provide a large-area display device, a vehicle head-up display device, and a virtual image display method.
  • the display device includes a light engine for generating an input image and converting the input image into input light, and a light engine for converting the input light into An image expander for expansion and a driving device for rotating the image expander to produce a large-area display;
  • the image expander includes an optical waveguide plate provided with an optical waveguide plate for coupling input light to the At least one input coupling element of the waveguide light and a first main output coupling element and a second main output coupling element for coupling out the waveguide light are formed on the optical waveguide plate and in the direction of the grating;
  • the input coupling element has a first input grating vector and a second input grating vector;
  • the first main output coupling element has a first output grating vector, and the second main output coupling element has a second main output grating vector; wherein the first input grating vector and
  • the embodiments of the present invention can display a large area of the image while reducing the difficulty and cost of manufacturing the display device.
  • Figure 1a shows a side view of the display device
  • Figure 1b shows a three-dimensional view of the display device
  • Figure 1c shows an axial view of the display device
  • Figure 1d shows the effective display area of the output coupling element in an axial view of the display device
  • Figure 2 shows a light emission timing diagram in the display area of the display device
  • Figure 3a shows an example of observing external objects through the window of the vehicle
  • Figure 3b shows an example diagram of receiving external light through a vehicle window
  • Figure 3c shows a schematic diagram of the driver receiving external light through the vehicle window and the output beam reflected by the vehicle window at the same time
  • Figures 4a to 4e respectively show the three-dimensional schematic diagram of the output beam generated by the light engine
  • Figure 4f shows a three-dimensional view of the virtual image
  • Figure 4g shows a schematic diagram of the angular width of the virtual image
  • Figure 4h shows a schematic diagram of the angular height of the virtual image
  • Figure 4i shows a schematic diagram of the wave vector of the input beam
  • Figure 5 shows the cross-sectional view of waveguide light propagation in the optical waveguide plate
  • Figure 6 shows an axial view of the diffraction element dimensions
  • Figure 7 shows an axial view of a pair of output coupling elements
  • Figure 8a shows a schematic diagram of an effective display area formed by the output light of all grating areas in the axial view
  • Figure 8b shows a schematic diagram of the position of the motor and light engine in the display device
  • Figure 8c shows another position diagram of the motor and light engine in the display device
  • Figure 9a shows an axial view of the image expander
  • Figure 9b shows an axial view of the image expander
  • Figure 9c shows a perspective view of the image expander shown in Figure 9b;
  • Figure 9d shows a schematic diagram that for the same image point, all output coupling elements can form mutually parallel output beams
  • Figure 10a shows an axial view of the first input grating vector V1a and the second input grating vector of the input coupling element
  • Figure 10b shows an axial view of the four grating vectors of the input coupling element
  • Figure 10c shows the angle relationship between the first input grating vector V1a and the second input grating vector of the input coupling element
  • Figure 11a shows a schematic diagram of four grating vectors of the input coupling element and four intermediate grating vectors formed by two adjacent grating vectors;
  • Figure 11b shows the directions of the four grating vectors of the input coupling element, and the direction and angle relationship of the four intermediate grating vectors formed by two adjacent grating vectors;
  • Figure 12a shows a schematic diagram of two gratings of the input coupling element arranged in an orthogonal manner
  • Figure 12b shows a schematic diagram of a two-dimensional grating of the input coupling element
  • Figure 12c shows a schematic diagram of the arrangement of two orthogonal gratings of the input coupling element
  • Figure 12d shows another schematic diagram of the arrangement of two orthogonal gratings of the input coupling element.
  • An embodiment of the present invention provides a large-area display device, including a light engine ENG1 for generating an input image and converting the input image into input light IN1, and expanding the input light IN1.
  • the image expander EPE1 and the driving device MOTOR1 for rotating the image expander EPE1 to produce a large area display;
  • the image expander ENG1 includes an optical waveguide plate SUB1.
  • the optical waveguide plate SUB1 is provided with an input coupling element DOE1 for coupling the input light IN1 to the optical waveguide plate SUB1 and forming at least one waveguide light in the grating direction.
  • a first main output coupling element DOE3a and a second main output coupling element DOE3b for coupling out the waveguide light;
  • the input coupling element DOE1 has a first input grating vector V 1a and a second input grating vector V 1c ;
  • the first main output coupling element DOE3a has a first output grating vector V 3a
  • the second main output coupling element DOE3b has a second main output grating vector V 3b ; wherein the vector sum of the first input grating vector V 1a and the first output grating vector V 3a is zero, and the second input grating vector V 1c and the second output grating vector V 3b
  • the vector sum of is zero, and the angle between the first input grating vector V 1a and the second input grating vector V 1c of the input coupling element DOE1 is 60° to 120°.
  • the large-area display device may include a light engine ENG1 for generating an input image, an image expander EPE1 for expanding the exit pupil image of the light engine ENG1, and a driving device ENG1 for rotating the image expander EPE1.
  • the rotation of the image expander EPE1 can provide a larger luminous display area, which is equivalent to a large virtual output coupling element.
  • This implementation allows the area of the actual display area to be determined by the rotation area, which is significantly larger than the area of the output coupling element of the image expander EPE1.
  • the rotating image expander EPE1 can expand the imaging area of the light engine so that the display device can emit output light from the entire area swept by the output coupling element. In this way, the display effect of a large Eye Box can be achieved through a small exit pupil, so that the display device can achieve a display effect of a large Eye Box through a small output coupling element.
  • the light engine ENG1 can convert the input image into input light.
  • the image expander EPE1 includes an optical waveguide plate SUB1, an input coupling element DOE1 that forms a first waveguide light and a second waveguide light by coupling input light into the optical waveguide plate SUB1, and an output by coupling the first waveguide light out of the optical waveguide plate SUB1.
  • the first main output coupling element DOE3a of light, and the second main output coupling element DOE3a of output light are formed by coupling the second waveguide light out of the optical waveguide plate SUB1.
  • the input light IN1 may include multiple input beams, and the output light OUT1 may include multiple output beams.
  • the grating vector of the input coupling element DOE1 and the grating vector of the output coupling element can be adjusted so that the direction of the output beam corresponds to the direction of the input beam.
  • the structural characteristics of the diffraction element are conducive to the mass production of image expanders.
  • the grating period of the diffraction grating can be adjusted so that the first output beam formed by the first main output coupling element DOE3a at the same image point can be parallel to the second output beam formed by the second main output coupling element DOE3b.
  • the rotary image expander EPE1 may include a plurality of output coupling elements, such as a first main output coupling element DOE3a and a second main output coupling element DOE3b, to reduce visually detectable flicker effects and/or to facilitate the display of color images.
  • the number of output coupling elements N OUT may equal 4, 5, 6, 7 or 8.
  • the flicker frequency of the displayed image is given by N OUT multiplied by the image expander's rotational speed f RPM .
  • Increasing the number of output coupling elements can increase the flicker frequency during imaging. When the frequency exceeds the resolution of the human eye, a clear and smooth picture can be achieved.
  • increasing the number of output coupling elements can reduce the image expander's rotational speed fRPM .
  • reducing the rotational speed f RPM can improve the rotation reliability and/or can reduce the audible noise generated when rotating the image expander EPE1.
  • the entire display area defined by the rotating image extender EPE1 can be regarded as a visually uniform display surface.
  • the input coupling element DOE1 includes a two-dimensional diffraction grating, each of the two-dimensional diffraction gratings has a corresponding grating period and a grating vector, and the size of the grating vector is inversely proportional to the grating period.
  • the input coupling element DOE1 includes two or more grating regions with different diffraction properties
  • the input coupling element DOE1 includes two one-dimensional diffraction gratings to generate diffraction in a first direction and a second direction, and the first direction is orthogonal to the second direction;
  • the one-dimensional diffraction grating or the two-dimensional diffraction grating has corresponding grating period and grating vector, and the size of the grating vector is inversely proportional to the grating period.
  • the input coupling element DOE1 may include two one-dimensional diffraction gratings or one two-dimensional diffraction grating to generate diffraction in the first direction and the second direction.
  • a diffraction grating has a grating period and a grating vector, where the magnitude of the grating vector is inversely proportional to the grating period.
  • the two-dimensional diffraction grating may have two grating periods.
  • the two-dimensional diffraction grating has a first input grating vector V 1a and a second input grating vector V 1c respectively.
  • the input coupling element DOE1 of the image expander EPE1 may be configured to form the first waveguide light B1a in the first direction and the second waveguide light B1c in the second direction, and the two directions are orthogonal.
  • the input coupling element may form a first waveguide light on a first input grating vector V 1a and a second waveguide light on a second light input grating vector V 1c .
  • the amplitude of the second input grating vector V 1c may be equal to or not equal to the first input grating vector V 1a .
  • the size of the second input raster vector V 1c may be equal to the size of the first raster input vector V 1a .
  • the image expander may include several output coupling elements to reduce visually detectable flicker effects, and/or to allow a reduction in rotational speed.
  • the input coupling element DOE1 can provide waveguide light in four directions, namely a first direction, a second direction orthogonal to the first direction, a third direction opposite to the first direction, and a second direction orthogonal to the first direction.
  • the fourth direction in the opposite direction.
  • the image expander EPE1 may include four main output coupling elements to couple out the waveguide light in four directions within the optical waveguide plate.
  • the image expander EPE1 may comprise four main output coupling elements such that the grating vector of each output coupling element may be opposite to the grating vector of the input coupling element DOE1.
  • the output coupling element can be arranged around the input coupling element.
  • the ability of the input coupling grating to couple the input light into the optical waveguide plate SUB1 through diffraction may depend on the incident angle and wavelength of the input beam, the grating period of the input coupling grating and the refractive index of the optical waveguide plate SUB1.
  • the ability of the input coupling grating to couple input light into SUB1 in the optical waveguide plate may limit the angular width of the displayed image.
  • the input coupling element DOE1 may have two different grating periods, such as a first grating period and a second grating period, to optimize color uniformity in multiple bands.
  • the first grating period may allow a first color component of the image (eg green) to be displayed.
  • a second different grating period (eg, a second grating period) may allow a second color component of the image (eg, red) to be displayed.
  • the first grating period may be selected to optimize input coupling, internal conduction, and/or output coupling at the first wavelength.
  • a second different grating period can be selected to optimize input coupling, internal conduction and/or output coupling at the second wavelength.
  • the amplitude of the second input raster vector V 1c may be different from the first input raster vector V 1a .
  • the amplitude of the second input raster vector V 1c may be different from the first input raster vector V 1a to facilitate the display of color images.
  • the light engine ENG1 and the display device 500 may be delivered separately, wherein the light engine ENG1 may be combined with the display device 500, such as by a retailer or by the end user.
  • the light engine ENG1 may be a replaceable part of the entire display device 500 .
  • the display device 500 is a vehicle head-up display.
  • the display device 500 can be used as a vehicle head-up display.
  • the large Eye Box of the display device 500 provides the user with a larger displayable area. For example, when the vehicle is driving on the road and the user's head vibrates according to the driving, the virtual image can still be clearly viewed.
  • the output coupling element may be produced using photolithography techniques.
  • an imprint template of a diffraction grating can be made by an electron beam lithography machine and transcribed using nanoimprint technology to produce diffraction grating elements in large quantities.
  • an increase in the size of the embossing template will significantly increase the production cost, and rotating the image expander can provide an enlarged display area without increasing the size of the embossing template.
  • the display device 500 may include a light engine ENG1 that generates input light IN1, an image expander EPE1 that forms output light OUT1 by expanding input light IN1, and a driving device ENG1 that enlarges the display area DAR1 by rotating the image expander ENG1.
  • the user USER1 can observe the displayed virtual image VIMG1 through the display device 500.
  • the input light IN1 may include a plurality of sub-input beams propagating in different directions. Each sub-input beam of the input light IN1 may correspond to a different pixel point of the input image IMG0.
  • the output light OUT1 may include multiple sub-output beams propagating in different directions.
  • the output light OUT1 may include a plurality of sub-output beams corresponding to different points of the virtual image VIMG1.
  • the image expander EPE1 can expand the input light IN1 into the output light OUT1, and make the beam direction and intensity of each sub-output beam of the output light OUT1 correspond to different pixel points of the input image IMG0.
  • the image expander EPE1 can expand the input beam through diffraction to form an output beam, so that each sub-output beam can propagate in the same direction as the corresponding sub-input beam. Therefore, the displayed virtual image VIMG1 may represent the input image IMG0.
  • the beam of input light IN1 may correspond to a single pixel point (P0) of the display image.
  • the direction of the output beam (k3 , P0, R ) is parallel to the direction of the corresponding input beam (k0 , P0, R ).
  • the light beams for different pixel points can propagate in different directions. The propagation directions of different pixel points are shown in Figures 4a to 4i.
  • the light engine ENG1 may generate input light IN1 corresponding to the input image IMG0, and at the same time, the input light IN1 may include a plurality of sub-input light beams propagating in different directions corresponding to different pixel points of the input image IMG0.
  • Light engine ENG1 may include a display DISP1 and collimating optics LNS1 to form the input beam.
  • the image expander EPE1 may include an optical waveguide plate SUB1, and the optical waveguide plate SUB1 may include an input coupling element DOE1 and one or more output coupling elements DOE3a, DOE3b, DOE3c, DOE3d.
  • the input coupling element DOE1 can couple the input light IN1 into the optical waveguide plate SUB1, where the irradiation area of the input light IN1 overlaps with the input coupling element DOE1.
  • the center point of the input coupling element DOE1 also needs to be coaxial with the rotation axis AX1.
  • Elements DOE1, DOE3a, DOE3b, DOE3c, DOE3d may be diffraction elements, wherein each diffraction element may include one or more diffraction gratings, wherein the diffraction gratings may be disposed on the first and/or second surface of the optical waveguide plate SUB1.
  • the input coupling element DOE1 can couple the input light IN1 into the optical waveguide plate SUB1 through diffraction to form the waveguide lights B1a and B1b.
  • the waveguide lights B1a and B1b propagate in the waveguide plate SUB1 by total reflection.
  • the output coupling elements DOE3a and DOE3b can couple the waveguide lights B1a and B1b out of the optical waveguide plate SUB1 through diffraction and form the output light OUT1.
  • the output coupling elements DOE3a and DOE3b may serve as a first pair of output coupling elements and are located on opposite sides of the input coupling element DOE1.
  • the output coupling elements DOE3c and DOE3d can couple the waveguide lights B1c and B1d out of the optical waveguide plate SUB1 through diffraction and form the output light OUT1, see Figure 9c.
  • the output coupling elements DOE3c and DOE3d can serve as the second pair of output coupling elements and are located on opposite sides of the input coupling element DOE1 and have an orthogonal relationship with the first pair of output coupling elements.
  • the first pair of output coupling elements DOE3a and DOE3b can optimize the first color component of the displayed image; the second pair of output coupling elements DOE3c and DOE3d can optimize the second color component of the displayed image.
  • the image expander EPE1 may serve as the exit pupil of the display device 500 in order to maintain the eye in a suitable position relative to the display device 500 .
  • the driving device MOTOR1 drives the image expander EPE1 to rotate and/or vibrate around a rotation axis AX1 and relative to a fixed base BASE1, wherein the relationship between the input coupling element DOE1 and the rotation axis AX1 The spacing is less than 5% of the diameter of the optical waveguide plate;
  • the light engine ENG1 is mechanically connected to the fixed base BASE1 through a protective cover 502.
  • the protective cover 502 is a transparent or translucent protective cover.
  • the image extender EPE1 may be arranged to rotate relative to the fixed base BASE1.
  • the display device 500 can be mounted on, for example, the vehicle 1000 via the base BASE1.
  • the display device 500 may be mounted to the vehicle 1000 via one or more connectors FIX1 , which may employ adhesive and/or threaded connectors.
  • the light engine ENG1 can be fixedly installed into the base BASE1 and remain relatively stationary.
  • the image extender EPE1 may be arranged to rotate and/or vibrate relative to the fixed base BASE1.
  • the display device 500 may include a driving device MOTOR1 to drive the image expander EPE1 to rotate and/or vibrate relative to the fixed base BASE1.
  • the drive device MOTOR1 may be an electric motor or a pneumatic turbine, and may be driven by, for example, The protective cover 502 and/or the fasteners are connected directly or indirectly into the base BASE1.
  • the driving device MOTOR1 can drive the image expander EPE1 to rotate around the rotation axis AX1 at an angular speed ⁇ 1, which corresponds to the rotation speed f RPM .
  • the light engine ENG1 may be mechanically connected into the base BASE1 by, for example, a protective cover 502 .
  • Protective cover 502 may be transparent or translucent.
  • the transparent cover 502 may include clear glass or plastic, and the translucent cover 502 may include a mesh with see-through properties.
  • the protective cover 502 also prevents the user from accidentally contacting the rotating image extender EPE1.
  • the light engine ENG1 can also be connected to the base BASE1 through a connecting structure.
  • the connection structure may be an open structure, since it is not always necessary to protect the rear side of the rotating image extender EPE1.
  • the symbol L EYE1 represents the distance between the image expander EPE1 and the user's eye EYE1.
  • the distance L EYE1 may be in the range of 0.1 m to 1.0 m, for example.
  • the optical waveguide plate SUB1 can be parallel to the plane defined by the directions SX and SY.
  • the input coupling element DOE1 can receive the input light IN1, and the output coupling element can provide the output light OUT1.
  • the input light IN1 may include a plurality of sub-input beams propagating in different directions.
  • the output light OUT1 may include a plurality of expanded beams (B3) formed by the sub-input beams (B0) of the input light IN1.
  • the image expander EPE1 forms an output light OUT1 by expanding the input light IN1.
  • the beam width w OUT1 of the output light OUT1 is greater than the beam width w IN1 of the input light IN1.
  • the image expander EPE1 can expand the input light IN1 in the direction of the grating vector (V 1 ) of the input coupling element DOE1.
  • the image expander EPE1 can expand the input light IN1 in the horizontal direction (SX); when the raster vector (V 1 ) is parallel to the vertical direction (SY), the image expander EPE1
  • the expander EPE1 can expand the input light IN1 in the vertical direction (SY).
  • the image expander EPE1 can gradually expand the horizontal cross-sectional width w OUT1 and vertical cross-sectional height h OUT1 of the neutron output beam (B3) of the output light OUT1. Therefore, the image expander EPE1 can effectively expand the input light IN1 in two-dimensional directions (eg, in the direction SX and in the direction SY) during the rotation process, and the expansion process may also be called exit pupil expansion.
  • the image expander EPE1 may also be called a beam expander or exit pupil expander.
  • the input coupling element DOE1 can form the waveguide light B1 or B1a, B1b by coupling the input light IN1 into the optical waveguide plate SUB1.
  • the waveguide lights B1, B1a, and B1b can propagate in the planar optical waveguide plate SUB1 and are limited on the optical waveguide plate SUB1 through total internal reflection.
  • the image expander (EPE1) can rotate around the rotation axis AX1 driven by the driving device (MOTOR1), where the circular path PATH1 is the multiple output coupling elements DOE3a, DOE3b, The rotation trajectories of DOE3c and DOE3d are generated, and a large display area DAR1 is generated.
  • the coordinates of any point POINT1 in the display area relative to the base BASE1 are (x1, y1).
  • the output coupling element will periodically pass through the point POINT1, so that the point POINT1 passes with the same cycle.
  • the output light OUT1 is emitted in a pulse manner. We can reduce the flickering effect caused by pulsed lighting by increasing the rotation speed (f RPM ).
  • each point of the display area DAR1 can sequentially emit the output light OUT1 in a pulse manner, so that the entire display area DAR1 also emits output in a pulse manner.
  • the symbol wEPE1 represents the width of the image expander EPE1 (when the image expander EPE1 stops rotating and the output coupling element DOE3a is aligned with the horizontal direction SX), the image expander EPE1 may be substantially circular, and the image expander EPE1 The diameter of EPE1 may be equal to the width wEPE1.
  • w DAR1 represents the width of the display area DAR1
  • h DAR1 represents the height of the display area DAR1
  • a DAR1 represents the effective surface area of the display area DAR1.
  • a DOE3 represents the surface area of the output coupling element DOE3 (or DOE3a).
  • the effective surface area A DAR1 of the display area DAR1 may be larger than the surface area A DOE3 of the output coupling element DOE3 (or DOE3a).
  • the image expander EPE1 and/or the driving device MOTOR1 can block the central area of the display area DAR1 so that the circular display area DAR1 has a dark center.
  • the display area DAR1 may be an annular area defined by an inner boundary BND2 and an outer boundary BND1, and the inner boundary BND2 may have a radius r 2DAR1 .
  • the outer boundary BND1 may have a radius r 1DAR1 .
  • Boundaries BND1 and BND2 are coaxial with the rotation axis AX1.
  • the central area of the image expander EPE1 can also provide output light OUT1, so that the circular display area DAR1 does not have a dark center (Fig. 8a).
  • the radius r1DAR1 of the outer boundary BND1 may be in the range of 4cm to 25cm.
  • the width w EPE1 of the image extender EPE1 can range from 8cm to 50cm.
  • the surface area A DAR1 of the display area DAR1 may range from 100 cm 2 to 2000 cm 2 .
  • w 1 represents the width of the input coupling element DOE1
  • h 1 represents the height of the input coupling element DOE1.
  • w IN1 represents the cross-sectional width of the input beam (IN1)
  • h IN1 represents the cross-sectional height of the input beam (IN1).
  • w3 represents the width of the output coupling element DOE3a
  • h3 represents the height of the output coupling element DOE3a.
  • w OUT1 represents the cross-sectional width of the output beam (OUT1)
  • h OUT1 represents the cross-sectional height of the output beam (OUT1).
  • the cross-sectional dimensions of the output light OUT1 may be defined by the dimensions of the output coupling element DOE3a, wherein the width w OUT1 is substantially equal to the width w 3 and/or the height h OUT1 may be substantially equal to the height h 3 .
  • the image extender EPE1 can be rotated relative to the base BASE1.
  • the optical axis AX0 of the light engine ENG1 may be coaxial with the rotation axis AX1 of the image expander EPE1
  • the input coupling element DOE1 may be coaxial with the rotation axis AX1 of the image expander EPE1.
  • the driving device MOTOR1 rotates the image expander EPE1 at a fixed rotation speed, and the fixed rotation speed is 5 to 200 revolutions per second.
  • the driving device MOTOR1 can be set to rotate the optical waveguide plate SUB1 at a rotational speed f RPM , and its rotational speed can be in the range of 5 to 200 revolutions per second.
  • the driving device MOTOR1 can drive the image expander EPE1 to rotate, so that the rotation speed f RPM of the image expander EPE1 is greater than or equal to 30 revolutions/second. At this time, it is difficult for the user to visually detect the flicker of the displayed image VIMG1.
  • the driving device MOTOR1 can drive the image expander EPE1 to rotate, so that the rotation speed f RPM of the image expander EPE1 is greater than or equal to 60 revolutions/second. At this time, it may be more difficult for the user to visually detect the flicker of the displayed image VIMG1.
  • the image expander EPE1 may be rotatably supported by one or more bearings of the drive device MOTOR1.
  • the drive device MOTOR1 and the light engine ENG1 can be on different sides of the image expander EPE1 (see Figure 1a) or on the same side of the image expander EPE1 (see Figures 8b, 8c).
  • the drive MOTOR1 may have a central opening (HOL1) to allow positioning the drive MOTOR1 and the light engine ENG1 on the same side of the image expander EPE1.
  • image expander EPE1 may operate as a rotating component of MOTOR1.
  • the image expander EPE1 may include magnets or coils to generate the force required for rotation.
  • the image extender EPE1 may also be rotatably supported by bearings at the edges or by needle bearings at the axis of rotation AX1.
  • Figure 2 shows the timing diagram of the local intensity IPOINT1 at any point in the display area DAR1 (for example, POINT1) when displaying the virtual image VIMG1.
  • the point POINT1 can be seen as emitting a beam to the eye EYE1 in a pulsed manner.
  • the image expander EPE1 includes four output coupling elements DOE3a, DOE3b, DOE3c, DOE3d.
  • DOE3a, DOE3b, DOE3c or DOE3d the intensity of point POINT1 reaches the maximum value I MAX ; when point POINT1 does not overlap any output coupling element, the intensity of point POINT1 is zero.
  • T ON represents the time period when point POINT1 overlaps any output coupling element, and also represents the duration of the light pulse emitted from point POINT1 when any output coupling element sweeps across said point POINT1.
  • T BLANK represents the time period when point POINT1 does not coincide with any output coupling element.
  • Point POINT1 is located in the area of the output coupling element DOE3a between times t 1a and t' 1a , between times t 2a and t' 2a , between times t 3a and t' 3a , and between times t 4a and t' 4a .
  • Point POINT1 is located in the area of the output coupling element DOE3b between time t 1b and t' 1b , between time t 2b and t' 2b and between time t 3b and t' 3b ; point POINT1 is between time t 1c and t ' 1c , time t 2c , t' 2c , time t 3c , t' 3c , and time t 4c , t' 4c are located in the area of the output coupling element DOE3c; point POINT1 is at time t 1d , Between t' 1d , time t 2d , t' 2d and time t 3d , t' 3d are located in the area of the output coupling element DOE3d.
  • the image expander EPE1 can for example be rotated in the direction shown in Figure 1, wherein said points POINT1 of the display area DAR1 can overlap in the same display position for any output coupling element, for example appearing in the following order: DOE3a, DOE3d, DOE3b, DOE3c , DOE3a, DOE3d, DOE3b, DOE3c,....
  • the light engine ENG1 can project red light, green light and blue light at the same time to display the color virtual image VIMG1. At this time, the image is expanded
  • the expander EPE1 needs to be set to display three bands; the light engine ENG1 can also be set to project only one color (for example, red, green or blue) to display the monochrome virtual image VIMG1. In this case, the image expander EPE1 needs to Set to a realistically corresponding color light.
  • the image expander EPE1 may form the output light OUT1 by expanding the input light IN1 generated by the light engine ENG1.
  • Light engine ENG1 may include a microdisplay DISP1 and collimation optics LNS1.
  • the microdisplay DISP1 can be used to display the input image IMG0
  • the collimating optical device LNS1 can be used to convert the input image IMG0 into the input light IN1.
  • the input image IMG0 may include a center point P0 and four corner points P1, P2, P3, and P4.
  • P1 can represent the upper left corner point.
  • P2 can represent the upper right corner point.
  • P3 can represent the lower left corner point.
  • P4 can represent the lower right corner point.
  • the input image IMG0 may include graphic characters "F", "G” and "H", for example.
  • the input image IMG0 may be a monochrome image, which is formed by modulating a laser or modulating one or more light emitting diodes.
  • the input image IMG0 may also be a color image, such as an RGB image, which may include a red partial image, a green partial image, and a blue partial image. Each image point can provide, for example, red, green or blue light.
  • Light engine ENG1 may provide input light IN1, which may include a plurality of substantially collimated light beams (B0).
  • each red beam may propagate in a different direction and may correspond to a different point of the input image IMG0.
  • Each beam can have a different color, for example, the subscript "R" can refer to red.
  • the red light beam B0 P0,R may correspond to the central image point P0 and may propagate in the direction of the wave vector k0 P0,R .
  • the red beam B0 P1,R can correspond to the image point P1, and can propagate in the direction of the wave vector k0 P1,R ;
  • the red beam B0 P2,R can correspond to the image point P2, and can propagate in the direction of the wave vector k0 P2,R propagates on;
  • the red beam B0 P3, R can correspond to the image point P3, and can propagate in the direction of the wave vector k0 P3, R ;
  • the red beam B0 P4, R can correspond to the image point P4, and can propagate in the direction of the wave vector k0 P4 , propagates in the direction of R.
  • the blue light beam (B0 P1,B ) may correspond to the image point P1 and may propagate in the direction of the wave vector (k0 P1,B ).
  • the input light IN1 may be formed such that the propagation direction (k0 P1,B) of the blue light beam (B0 P1,B ) corresponding to the first corner point P1 of the input image IMG0 can be consistent with the propagation direction (k0 P1,B ) of the red light beam (B0 P1,R ).
  • the propagation direction (k0 P1,R ) is parallel; for example, the input light IN1 can be formed such that the propagation direction (k0 P2,B) of the blue light beam (B0 P2 ,B ) corresponding to the second corner point P2 of the input image IMG0 can Parallel to the propagation direction (k0 P2,R ) of the red light beam (B0 P2,R) .
  • the wave vector (k) of light can be defined as the direction of propagation of the light, and its magnitude is given by 2 ⁇ / ⁇ , where ⁇ is the wavelength of the light.
  • the light B0P0,R at the center point P0 can propagate along the axial direction (k0 P0,R ).
  • the axial direction (k0 P0,R ) may be parallel to the optical axis (AX0) of the light engine ENG1.
  • the output light OUT1 may include a plurality of sub-output beams B3 P1,R , B3 P2,R , ..., which may correspond to points P1', P2', ... of the displayed virtual image VIMG1.
  • the red light beam B3 P0,R propagating in the direction of the wave vector k3 P0,R can correspond to the point P0' of the image VIMG1; the red light beam B3 P1,R propagating in the direction of the wave vector k3 P1,R can correspond to The point P1' of the image VIMG1; the red light beam B3 P2,R propagating in the direction of the wave vector k3 P2 ,R can correspond to the point P2' of the image VIMG1; the red light beam B3 propagating in the direction of the wave vector k3 P3,R P3,R may correspond to point P3'.
  • a red light beam B3 P4,R propagating in the direction of the wave vector k3 P4,R may correspond to point P4'.
  • the image expander EPE1 can form the output light OUT1 by expanding the exit pupil of the light engine ENG1.
  • the output light OUT1 may include a plurality of sub-output beams, which respectively correspond to each image point of the displayed virtual image VIMG1.
  • the output light OUT1 can illuminate the observer's eyes EYE1, so that the observer sees the displayed virtual image VIMG1.
  • 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 beams corresponding to points P0, P1, P2, P3, P4 of the input image IMG0.
  • the image expander EPE1 the sub-input light corresponding to the point P0 of the input image IMG0 can be converted into the sub-output light corresponding to the point P0' of the displayed virtual image VIMG1 through diffraction and total internal reflection.
  • the input light IN1 will be diffracted under the action of the input coupling element DOE1, and the input light IN1 will be coupled into the optical waveguide plate SUB1 to form waveguide light B1, B1a, and B1b.
  • the waveguide light includes the optical information of the center point P0 of the input image IMG0.
  • the waveguide lights B1, B1a, and B1b are coupled out of the optical waveguide plate SUB1 through diffraction under the action of the corresponding output coupling elements DOE3, DOE3a, and DOE3b respectively, forming the output light OUT1, so that The output light OUT1 contains all the light information of the center point P0.
  • the image expander EPE1 can convert points P1, P2, P3, and P4 into points P1', P2', P3', and P4' through diffraction and total internal reflection.
  • the image expander EPE1 can expand the input light IN1 so that each output beam B3 P1,R , B3 P2,R , B3 P3,R ,... can be connected to the corresponding input beam B0 P1,R , B0 P2,R , B0 P3,R ,... propagate in the same direction.
  • image expander EPE1 can convert input beam B0 P1,R into output beam B3 P1,R such that output beam B3 P1,R propagates in the same direction as input beam B0 P1,R , while beam B0 P1,R , B 3P1,R corresponds to the same point P1 of the input image IMG0.
  • image expander EPE1 can convert input beam B0 P2,R into output beam B3 P2,R such that output beam B3 P2,R propagates in the same direction as input beam B0 P2,R , while beam B0 P2,R , B3 P2,R may correspond to the same point P2 of the input image IMG0.
  • the image expander EPE1 can make the wave vector k3P1,R parallel to the wave vector k0 P1,R of the red light at point P1 in the input light IN1; the wave vector k3 P0,R can be parallel to the wave vector k0 P0,R of point P0;
  • the wave vector k3 P2, R can be parallel to the wave vector k0 P2, R of point P2; the wave vector k3 P 3, R can be parallel to the wave vector k0 P3, R of point P3; the wave vector k3 P4, R can be parallel to the wave vector of point P4 Vector k0 P4, R is parallel.
  • the displayed virtual image VIMG1 has an angular width and angular height ⁇ .
  • the displayed virtual image VIMG1 may have a first corner point P1' on the left and a second corner point P2' on the right, where the angular width of the virtual image VIMG1 It can be equal to the horizontal angle between the wave vectors k3 P1,R and k3 P2,R of the corner points P1' and P2'.
  • the displayed virtual image VIMG1 may have an upper corner point P1' and a lower corner point P3', wherein the angular height ⁇ of the virtual image VIMG1 may be equal to between the wavevectors k3 P1,R and k3 P3,R of the corner points P1' and P3' vertical angle.
  • the direction of the wave vector can be determined by e.g. the direction angle and ⁇ to specify.
  • angle can represent the angle between the wave vector and the reference plane REF1, where the reference plane REF1 is defined by SZ and SY;
  • angle ⁇ can represent the angle between the wave vector and the reference plane REF2, where the reference plane REF2 is defined by SZ and SX.
  • the input light IN1 may include red light (R), green light (G) and/or blue light (B).
  • the input light IN1 may include a blue input beam whose wavevectors may be k0 P0,B , k0 P1,B , k0 P2,B , k0 P3,B , k0 P4,B , respectively corresponding to the blue color of the image IMG0 Image points P0, P1, P2, P3, P4.
  • the image expander EPE1 can convert a blue input beam into a blue output beam such that the wave vector of each blue output beam is parallel to the wave vector of the corresponding blue input beam.
  • the light engine ENG1 may import an input image IMG0 and may convert the input image IMG0 into a plurality of sub-input beams of the input light IN1 .
  • One or more sub-input beams provided by the light engine ENG1 may be coupled into the image expander EPE1 through the input coupling element DOE1 as input light IN1.
  • the input image IMG0 can represent information such as graphics, text, video, etc.
  • the light engine ENG1 can generate still images and/or videos, can generate a real master image IMG0 from a digital image, or can receive one or more digital images from an Internet server or from a smartphone.
  • the image expander EPE1 can transmit virtual image content from the light engine ENG1 to the front of the user's eyes EYE1.
  • the image expander EPE1 can expand the eye pupil, thereby enlarging the Eye Box.
  • the light engine ENG1 may include a microdisplay DISP1 to generate the input image IMG0.
  • Microdisplay DISP1 may comprise a two-dimensional array of pixels that emit light.
  • Light engine ENG1 may include, for example, one or more light emitting diodes (LEDs).
  • the microdisplay DISP1 may include display devices such as liquid crystal on silicon (LCOS), liquid crystal display (LCD), digital micromirror array (DMD), micron light-emitting diode (Micro LED), etc.
  • the bit display DISP1 can generate the input image IMG0 with a resolution of, for example, 1280 ⁇ 720 (HD), or with a resolution of 1920 ⁇ 1080 (Full HD), or with a resolution of 3840 ⁇ 2160 (4K UHD).
  • the input image IMG0 may include multiple image points P0, P1, P2, ....
  • Light engine ENG1 may include collimating optics LNS1 to form collimated light beams in different directions from each image pixel.
  • the center of the microdisplay DISP1 and the center of the collimating optics LNS1 may together define the optical axis AX0 of the light engine ENG1.
  • the optical waveguide plate SUB1 may have a first main surface SRF1 and a second main surface SRF2.
  • the surfaces SRF1, SRF2 should be highly parallel to the plane defined by the directions SX and SY.
  • the optical waveguide plate SUB1 may comprise or consist essentially of a transparent solid material.
  • the waveguide plate SUB1 may comprise, for example, glass, polycarbonate or polymethylmethacrylate (PMMA).
  • the diffractive optical elements DOEl, DOE3a, DOE3b, DOE3c, DOE3d may be formed, for example, by molding, embossing and/or etching.
  • Diffractive optical elements DOE1, DOE3a, DOE3b, DOE3c, DOE3d can be realized, for example, by one or more surface relief gratings or by one or more volume holographic gratings.
  • the thickness of the optical waveguide plate SUB1 is t SUB1 .
  • the waveguide plate includes a planar waveguide core.
  • the waveguide plate SUB1 may include one or more cladding layers, one or more protective layers, and/or one or more mechanical support layers.
  • the thickness t SUB1 may also refer to the thickness of the planar waveguide core of the optical waveguide plate SUB1.
  • each element DOEl, DOE3a, DOE3b, DOE3c, DOE3d may include one or more diffraction gratings to generate diffracted light.
  • input coupling element DOEl may include one or more gratings G1a.
  • the output coupling element DOE3a may comprise a grating G3a.
  • output coupling element DOE3b may include grating G3b.
  • the grating period (d) of the diffraction grating and the grating direction ( ⁇ ) of the diffraction grating can be specified by the grating vector V of the diffraction grating.
  • the diffraction grating includes a plurality of diffraction features (F1a, F3a) as diffraction lines.
  • the diffraction features can be, for example, microscopic ridges or grooves, or microscopic protrusions (or depressions), where adjacent rows of protrusions (or depressions) can act as diffraction lines.
  • the value of the grating vector V is 2 ⁇ /d, and its direction is perpendicular to the diffraction line of the diffraction grating, where d is the grating period.
  • the grating period may be the length between consecutive diffractive features of the grating, or the unit length divided by the number of diffractive features located within said unit length.
  • the grating period d 1a of the input coupling element DOE1 may for example be in the range of 330 nm to 450 nm.
  • the optimal value of the grating period d depends on the refractive index of the optical waveguide plate SUB1 for the wavelength ⁇ .
  • the grating vector of the input coupling element DOE1 may be V 1a , and the first waveguide light B1a is formed by diffraction of the input light IN1.
  • the input coupling element DOE1 has a diffraction grating G1a with diffraction characteristic F1a, grating period d 1a , grating direction ⁇ 1a and orientation relative to the reference direction SX.
  • the diffractive features of grating G1a may be, for example, microscopic ridges or microscopic protrusions.
  • the grating vector of the output coupling element DOE3a may be V 3a , and the waveguide light B1a is coupled out of the optical waveguide plate SUB1 through diffraction.
  • the output coupling element DOE3a has a diffraction grating G3a with diffraction characteristic F3a, grating period d3a , grating direction ⁇ 3a and orientation relative to the reference direction SX.
  • the diffraction features of grating G3a may be, for example, microscopic ridges or microscopic protrusions.
  • the direction of the grating vector V 1a is ⁇ 1a and the amplitude is 2 ⁇ /d1a; the direction of the grating vector V 3a is ⁇ 3a and the amplitude is 2 ⁇ /d3a.
  • the direction ( ⁇ ) of a raster vector may be specified by the angle between said vector and a reference direction (eg direction SX).
  • the grating period (d) and grating direction ( ⁇ ) of the diffraction grating of the optical element can be selected so that the propagation direction of the main ray in the output light OUT1 (k3 P0,R ) is consistent with the propagation direction of the main ray in the input light IN1 (k0 P0, R ) are the same.
  • the grating period (d) and grating direction ( ⁇ ) of the diffraction grating of the optical elements DOE1, DOE3a, DOE3b, DOE3c, and DOE3d can be selected so that the propagation direction of each sub-output beam of the output light OUT1 can be parallel to the sub-section corresponding to the input light IN1. Enter the propagation direction of the beam.
  • the output coupling elements DOE3a and DOE3b may together form a first pair of output coupling elements; the output coupling elements DOE3c and DOE3d may together form a second pair of output coupling elements.
  • the image extender EPE1 can maintain a mechanical balance relative to the rotation axis AX1, thereby minimizing or eliminating mechanical vibration caused by the rotation of the image extender EPE1.
  • the image expander EPE1 can be statically balanced so that the focus of the image expander EPE1 falls on the rotation axis AX1; the image expander EPE1 can also be dynamically balanced so that rotation around the axis AX1 does not generate any centrifugal force.
  • the input coupling element DOE1 can also provide the output light OUT1.
  • the input coupling element DOE1 may form the central part OUT1C of the output light OUT1.
  • the intensity of the directly transmitted input light IN1 is high, and the transmitted input light IN1 may cause a dazzling effect on the user's eyes EYE1.
  • the display device 500 can attenuate the intensity of the output light OUT1C by setting the filter FIL1, so that the intensity of the output light OUT1C provided by the input coupling element DOE1 is substantially equal to the effective intensity of the output light OUT1 provided by the output coupling elements DOE3a, DOE3b.
  • the filter FIL1 may be realized by depositing a semi-reflective layer and/or an absorbing layer on the main surface SRF2 of the image expander EPE1.
  • the drive device MOTOR1 can be a motor.
  • the drive device MOTOR1 and the light engine ENG1 can be arranged on the same side of the image expander EPE1.
  • the display device 500 may include a data transmission line BUS1 for passing the driving device MOTOR1 Transfer the image data DATA1 to the light engine ENG1.
  • the driving device MOTOR1 may be composed of an inner rotating rotor ROTO1 and an outer stationary stator STAT1. Among them, the stator STAT1 is stationary relative to the base BASE1, and the rotor ROTO1 rotates relative to the base BASE1.
  • the driving device MOTOR1 and the light engine ENG1 may be located on the rear side of the image expander EPE1 so that the driving device MOTOR1 does not block the central area of the display area DAR1.
  • the display device 500 may include a data transmission line BUS1 for transmitting the image data DATA1 to the microdisplay DISP1 in the light engine ENG1 through the driving device MOTOR1.
  • the display device 500 may include a lead FEED1 for transmitting image data DATA1, where the lead FEED1 may include a data transmission line BUS1 that can be connected to the light engine ENG1 through the central opening HOL1 of the driving device MOTOR1.
  • the central opening HOL1 can also accommodate a fixed support element CE1 for mechanically supporting the light engine ENG1.
  • the stator STAT1 can be fixed directly or indirectly to the base BASE1.
  • the stator STAT1 can support the microdisplay DISP1 so that the display DISP1 is stationary relative to the base BASE1.
  • the fixed support element CE1 can mechanically connect the light engine ENG1 to the base BASE1 via the central opening HOL1 of the driving device MOTOR1, while the fixed support element CE1 can be directly or indirectly connected to the base BASE1.
  • the fixed support element CE1 allows the display DISP1 to remain stationary relative to the base BASE1.
  • the fixed support element CE1 may be a fixed shaft connecting the light engine ENG1 to the base BASE1.
  • the transmission line BUS1 may be an electrical and/or optical data transmission line.
  • the second rotation support element CE2 can be configured to mechanically connect the rotor ROTO1 to the image expander EPE1 so that the rotational motion of the rotor ROT1 is transmitted to the image expander EPE1.
  • the second rotating support element CE2 may partially or completely surround the light engine ENG1.
  • the driving device MOTOR1 may be composed of an external rotating rotor ROTO1 and an internal stationary stator STAT1. Among them, the stator STAT1 is stationary relative to the base BASE1, and the rotor ROTO1 rotates relative to the base BASE1.
  • the driving device MOTOR1 and the light engine ENG1 may be located on the rear side of the image expander EPE1 so that the driving device MOTOR1 does not block the central area of the display area DAR1.
  • the display device 500 may include a data transmission line BUS1 for transmitting the image data DATA1 to the microdisplay DISP1 in the light engine ENG1 through the driving device MOTOR1.
  • the display device 500 may include a lead FEED1 for transmitting image data DATA1, where the lead FEED1 may include a data transmission line BUS1 that can be connected to the light engine ENG1 through the central opening HOL1 of the driving device MOTOR1.
  • the central opening HOL1 can also accommodate a fixed support element CE1 for mechanically supporting the light engine ENG1.
  • the stator STAT1 can be fixed directly or indirectly to the base BASE1.
  • the stator STAT1 can support the microdisplay DISP1 so that the display DISP1 is stationary relative to the base BASE1.
  • the fixed support element CE1 can mechanically connect the light engine ENG1 to the base BASE1 via the central opening HOL1 of the driving device MOTOR1, while the fixed support element CE1 can be directly or indirectly connected to the base BASE1.
  • the fixed support element CE1 allows the display DISP1 to remain stationary relative to the base BASE1.
  • the fixed support element CE1 may be a fixed shaft connecting the light engine ENG1 to the base BASE1.
  • the transmission line BUS1 may be an electrical and/or optical data transmission line.
  • the second rotation support element CE2 can be configured to mechanically connect the rotor ROTO1 to the image expander EPE1 so that the rotational motion of the rotor ROT1 is transmitted to the image expander EPE1.
  • the second rotating support element CE2 may partially or completely surround the light engine ENG1.
  • the optical waveguide plate SUB1 is further provided with a third main output coupling element DOE3c, the third main output coupling element DOE3c has a third output grating vector, the third input grating vector and the third The vector sum of the output grating vectors is zero; the input coupling element DOE1 is located between the first main output coupling element DOE3a and the third main output coupling element DOE3c;
  • the optical waveguide board SUB1 is also provided with a fourth main output coupling element DOE3d, the fourth main output coupling element DOE3d has a fourth output grating vector, the fourth input grating vector and the fourth output grating The vector sum of vectors is zero; the input coupling element DOE1 is located between the second main output coupling element DOE3d and the fourth main output coupling element DOE3d.
  • the image expander EPE1 may include four main output coupling elements DOE3a, DOE3b, DOE3c, DOE3d.
  • the input coupling element DOE1 may be located between the first main output coupling element DOE3a and the third output coupling element DOE3b, and also between the second main output coupling element DOE3c and the fourth output coupling element DOE3d.
  • the input coupling element DOE1 can provide waveguide light B1a, B1b, B1c, and B1d in four directions, that is, the first direction, the reverse direction of the first direction, and the two directions orthogonal to the first direction.
  • the first main output coupling element DOE3a can couple the first waveguide light B1 out of the optical waveguide plate SUB1 through diffraction.
  • the second main output coupling element DOE3b can couple the second waveguide light B2 out of the optical waveguide plate SUB1 through diffraction.
  • the third output coupling element DOE3c can couple the third waveguide light B3 out of the optical waveguide plate SUB1 through diffraction.
  • the fourth output coupling element DOE3d can couple the fourth waveguide light B4 out of the optical waveguide plate SUB1 through diffraction.
  • the waveguide light formed by the input coupling element DOE1 includes intermediate waveguide light (B1e, etc. in the figure);
  • the optical waveguide plate SUB1 is also provided with at least one intermediate output element (DOE3e, etc. in the figure) for optically coupling out the intermediate waveguide.
  • the intermediate output element is located between the first main output coupling element DOE3a and the second main output Between the coupling elements DOE3b, the intermediate output element has an intermediate output grating vector, and makes the vector sum of the first input grating vector V 1a , the second input grating vector V 1c and the intermediate output grating vector zero.
  • the image expander EPE1 may include one or more intermediate output coupling elements DOE3e, DOE3f, DOE3g, DOE3h.
  • the image expander EPE1 may comprise one or more intermediate output coupling elements DOE3e, DOE3f, DOE3g, DOE3h instead of or in addition to one or more main output coupling elements DOE3a, DOE3b, DOE3c, DOE3d.
  • the input coupling element DOE1 can form the waveguide light B1a, B1b , B1c , B1d in the main directions specified by the grating vectors V1a , V1b, V1c, V1d of the input coupling element DOE1.
  • the input coupling element DOE1 can also form intermediate waveguide lights B1e, B1f, B1g, and B1h in the directions specified by two adjacent grating vectors.
  • the intermediate output coupling elements DOE3e, DOE3f, DOE3g, and DOE3h can couple the intermediate waveguide lights B1e, B1f, B1g, and B1h out of the optical waveguide plate SUB1.
  • the main output coupling elements DOE3a, DOE3b, DOE3c, DOE3d and the intermediate output coupling elements DOE3e, DOE3f, DOE3g, DOE3h may be arranged around the input coupling element DOE1.
  • the intermediate output coupling element DOE3e may be located between the main output coupling elements DOE3a, DOE3c.
  • the intermediate output coupling element DOE3f may be located between the main output coupling elements DOE3b, DOE3d.
  • the intermediate output coupling element DOE3g may be located between the main output coupling elements DOE3b, DOE3c.
  • the intermediate output coupling element DOE3h may be located between the main output coupling elements DOE3a, DOE3d.
  • the input coupling element DOE1 may be located between the intermediate output coupling elements DOE3e, DOE3f.
  • the input coupling element DOE1 may be located between the intermediate output coupling elements DOE3g, DOE3h.
  • each output coupling element may form part of the output light OUT1.
  • the output coupling element DOE3a can form B3a in the output light OUT1 by coupling the waveguide light B1 out of the optical waveguide plate SUB1 through diffraction.
  • the output coupling element DOE3b can form B3b in the output light OUT1 by diffracting the waveguide light B1b.
  • the output coupling element DOE3c can form B3c in the output light OUT1 by diffracting the waveguide light B1c.
  • the output coupling element DOE3d can form B3d in the output light OUT1 by diffracting the waveguide light B1d.
  • the intermediate output coupling element DOE3e can form B3e in the output light OUT1 by diffracting the waveguide light B1e.
  • the intermediate output coupling element DOE3f can form B3f in the output light OUT1 by diffracting the waveguide light B1f.
  • the intermediate output coupling element DOE3g can form B3g in the output light OUT1 by diffracting the waveguide light B1g.
  • the intermediate output coupling element DOE3h can form B3h in the output light OUT1 by diffracting the waveguide light B1h.
  • the beams B3a, B3b, B3c, B3d, B3e, B3f, B3g, and B3h in the output light can be parallel to each other for the same image point.
  • the output coupling elements may form output beams such that the direction and intensity of each output beam may correspond to the position and brightness of the same image point of the displayed image VIMG1.
  • each output coupling element DOE3a, DOE3b, DOE3c, DOE3d, DOE3e, DOE3f, DOE3g, DOE3h can form an output beam such that the output beam (B3a P0,R , B3b P0,R , B3c P0,R , B3dP0,R ,B3e P0,R ,B3f P0,R ,B3g P0,R ,B3h P0,R ) are parallel to each other under different output coupling elements, where the output beam corresponds to the same image point (P0) of the displayed image VIMG1, below
  • the mark "R" indicates red color light.
  • Outputting a parallel beam ensures that the displayed image point (P0) is visually displayed as a single point, and also ensures that the Rotation of the display device EPE1 does not cause a visually detectable shift of the displayed image point (P0).
  • the input coupling element DOEl may have a first input grating vector V 1a and a second input grating vector V 1c .
  • the magnitude of the first input grating vector V 1a may be determined by the grating period d 1a of the diffraction grating G1a of the input coupling element DOE1.
  • the direction of the first input grating vector V 1a may be specified by the angle ⁇ 1a relative to the reference direction.
  • the reference direction can also be, for example, the SX direction, when the image expander EPE1 is stationary.
  • the image expander EPE1 can be in a rotating or stationary state such that the first input grating vector V 1a is parallel to the SX direction.
  • the magnitude of the second input grating vector V 1c may be determined by the grating period d 1c of the diffraction grating G1c of the input coupling element DOE1.
  • the direction of the second input grating vector V 1c may be specified by the angle ⁇ 1c relative to the reference direction.
  • Diffraction grating G1a may comprise diffraction features F1a.
  • Diffraction grating G1c may comprise diffractive features F1c.
  • the diffractive features F1a, F1c may be, for example, microscopic ridges or grooves (see Figure 12a).
  • the input coupling element DOE1 may also comprise a two-dimensional grating G1 consisting of a two-dimensional array of diffractive features F1 (see Figure 12b).
  • the input coupling element DOE1 may have two different grating periods d 1a and d 1c to optimize the uniformity problem with polychromatic light.
  • the first grating period d 1a may allow the first color component of the image to be displayed (eg green G).
  • the second grating period d 1c may allow a second color component of the image to be displayed (eg red R).
  • the amplitude of the raster vector V 1c may be different from the raster vector V 1a to facilitate the display of color images.
  • the first grating period d 1a of the input coupling element DOE1 may be equal to the second grating period d 1c of the input coupling element DOE1 .
  • the amplitude of the first input grating vector V 1a of the input coupling element DOE1 may be equal to the amplitude of the second input grating vector V 1c of the input coupling element DOE1.
  • the image extender EPE1 may comprise, for example, four or more output coupling elements DOE3a, DOE3b, DOE3c, DOE3d, in order to reduce visually detectable flicker and/or to allow a reduced rotational speed of the image extender EPE1 .
  • the input coupling element DOEl may also have a third input grating vector V 1b and a fourth input grating vector V 1d .
  • the magnitude of the third input grating vector V 1b may be equal to the first input grating vector V 1a , and the direction of the third input grating vector V 1b may be opposite to the first input grating vector V 1a .
  • the amplitude of the fourth input raster vector V 1d may be equal to the second input raster vector V 1c , and the direction of the fourth input raster vector V 1d may be opposite to the second input raster vector V 1b .
  • angle ⁇ 1ac between the grating vectors V 1a , V 1c may be in the range of 60° to 120°, for example.
  • angle ⁇ 1ac is essentially equal to 90°.
  • the input coupling element DOE1 may also provide intermediate waveguide light to an intermediate direction specified by the sum of the grating vectors of the input coupling element DOE1.
  • the input coupling element DOE1 can provide the first intermediate waveguide light B1e to the direction specified by the vector V 1a + V 1b ;
  • the input coupling element DOE1 can provide the first intermediate waveguide light B1f to the direction specified by the vector V 1b + V 1d direction;
  • the input coupling element DOE1 can provide the first intermediate waveguide light B1g to the direction specified by the vector V 1b + V 1c ;
  • the input coupling element DOE1 can provide the first intermediate waveguide light B1h to the direction specified by the vector V 1a + V 1d direction.
  • the magnitude of the first input raster vector V1a may be equal to or different from the magnitude of the first input raster vector V1aV1c .
  • the direction angle ⁇ 1e of the first intermediate direction may not be equal to 45°.
  • the diffraction characteristics of the output coupling elements can be selected so that the output beams formed by different output coupling elements are parallel to each other.
  • the main output coupling element DOE3a may have a diffraction grating G3a containing diffraction features F3a with a grating period d3a .
  • the direction of the grating vector V 3a of the output coupling element DOE3a is specified by the direction angle ⁇ 3a .
  • the main output coupling element DOE3b may have a diffraction grating G3b containing diffraction features F3b with a grating period d 3b .
  • the direction of the grating vector V 3b of the output coupling element DOE3b is specified by the direction angle ⁇ 3b .
  • the main output coupling element DOE3c may have a diffraction grating G3c containing diffraction features F3c with a grating period d 3c .
  • the direction of the grating vector V 3c of the output coupling element DOE3c is specified by the direction angle ⁇ 3c .
  • the main output coupling element DOE3d may have a diffraction grating G3d containing diffraction features F3d with a grating period d 3d .
  • the direction of the grating vector V 3d of the output coupling element DOE3d is specified by the direction angle ⁇ 3d .
  • the intermediate output coupling element DOE3e may have a diffraction grating G3e containing diffraction features F3e with a grating period d 3e .
  • the direction of the grating vector V 3e of the output coupling element DOE3e is specified by the direction angle ⁇ 3e .
  • the intermediate output coupling element DOE3f may have a diffraction grating G3f containing diffraction features F3f with a grating period d 3f .
  • the direction of the grating vector V 3f of the output coupling element DOE3f is specified by the direction angle ⁇ 3f .
  • the intermediate output coupling element DOE3g may have a diffraction grating G3g containing diffraction features F3g with a grating period d 3g .
  • the direction of the grating vector V 3g of the output coupling element DOE3g is specified by the direction angle ⁇ 3g .
  • the intermediate output coupling element DOE3h may have a diffraction grating G3h containing diffraction features F3h with a grating period d 3h .
  • the direction of the grating vector V 3h of the output coupling element DOE3h is specified by the direction angle ⁇ 3h .
  • the grating vector V 1b and the grating vector V 1a have the same amplitude and the opposite direction; the grating vector V 1c and the grating vector V 1d have the same amplitude and the opposite direction.
  • each output coupling element can selectively diffract waveguide light to provide optimal image quality. In other words, the formation of ghost images can be reduced or avoided.
  • the input coupling element DOE1 may include a first grating region G1a to provide grating vectors V 1a and V 1b , and the input coupling element DOE1 may also include a second grating region G1a to provide grating vectors V 1c and V 1d .
  • the input coupling element of DOEl may comprise a two-dimensional grating to provide four grating vectors V 1a , V 1b , V 1c , V 1d .
  • a two-dimensional grating may comprise, for example, a two-dimensional array of microscopic diffractive protrusions or depressions.
  • the image expander may include four main output coupling elements that couple the waveguide light out of the optical waveguide plate through diffraction.
  • the image expander may include four main output coupling elements, each of which has a grating vector that is opposite to a corresponding grating vector of the input coupling element.
  • the grating period (d) and the direction of the grating vector ( ⁇ ) of the main output coupling element (DOE3a, DOE3b, DOE3c, DOE3d) can be selected to meet the following conditions, so that the output beams provided by different output coupling elements can be for the same image point Keep parallel.
  • V 1a + V 3a 0 (2a)
  • V 1b + V 3b 0 (2b)
  • V 1c + V 3c 0 (2c)
  • V 1d + V 3d 0 (2d)
  • the diffraction characteristic F3a of the first main output coupling element DOE3a may be chosen such that the sum of the first input grating vector V 1a and the first output grating vector V 3a is zero.
  • the diffraction characteristic F3c of the second main output coupling element DOE3c may be chosen such that the sum of the second input grating vector V 1c and the second output grating vector V 3c is zero.
  • the total of the input raster vector V 1b and the output raster vector V 3b can be zero.
  • the sum of the input raster vector V 1d and the output raster vector V 3d may be zero.
  • the image expander may also include one, two, three or four intermediate output coupling elements that couple the waveguide light out of the optical waveguide plate by diffraction.
  • the image expander may include four intermediate output coupling elements such that the grating vector of each intermediate output coupling element may sum to zero with the vector sum of two adjacent input grating vectors.
  • the grating period (d) and the direction of the grating vector ( ⁇ ) of the intermediate output coupling element (DOE3e, DOE3f, DOE3g, DOE3h) can be selected to meet the following conditions, so that the output beams provided by different intermediate output coupling elements can be used for the same image.
  • the points remain parallel.
  • V 1a +V 1c +V 3e 0 (3a)
  • V 1b +V 1d +V 3f 0 (3b)
  • V1b+V 1c +V 3g 0 (3c)
  • V 1a +V 1d +V 3h 0 (3d)
  • Formulas (1a) to (3d) specify the conditions for the grating vector sum in the waveguide, where each term of formulas (1a) to (3d) is a vector, with Has size and direction.
  • the position of the diffraction feature F3e of the first intermediate output element DOE3e may be chosen such that the sum of the first input grating vector V 1a , the second input grating vector V 1c and the first intermediate output grating vector V 1e is equal to zero.
  • the input coupling element DOE1 may include a first grating region G1a having a grating period d 1a and a grating vector V 1a .
  • the input coupling element DOE1 may comprise a second grating region G1c having a grating period d 1c and a grating vector V 1c .
  • the grating area G1a has a diffraction characteristic F1a.
  • Grating area G1c has diffraction characteristics F1c.
  • the diffractive features F1a, F1c may be, for example, microscopic ridges or grooves.
  • the first grating area G1a may be provided, for example, on the first main surface SRF1 of the optical waveguide plate SUB1, and the second grating area G1c may be provided, for example, on the second main surface SRF2 of the optical waveguide plate SUB1.
  • the first grating area G1a may partially or completely overlap the second grating area G1c.
  • the input coupling element DOEl may comprise a two-dimensional grating Gl having a first input grating vector V 1a and a second input grating vector V 1c .
  • the two-dimensional grating G1 may have a first grating period d 1a and a second grating period d 1c .
  • the two-dimensional grating G1 may have a two-dimensional array of diffractive features F1. Diffractive features F1 may be, for example, microscopic protrusions or depressions.
  • the input coupling element DOE1 may include two or more spatially independent grating regions G1a, G1b, G1c, G1d, such that the in-coupling element DOE1 may have grating vectors V1a , V1c .
  • Each formed waveguide light can only be coupled out through one output coupling element. Diffraction from the wrong output coupling element can lead to the formation of visually disturbing ghost images.
  • the location of the diffraction features of the grating element can be selected so that the image expander does not form or reduces or avoids ghost images.
  • the position of the diffraction features of the grating element can be chosen so that the directions of any pair of grating vectors are equal to or sufficiently different from each other to reduce or avoid the formation of ghost images.
  • the position of the diffraction features of the grating elements can be chosen so that the amplitudes of the grating vectors of each output coupling element are equal, thereby reducing or avoiding the formation of ghost images.
  • the angle between the grating vectors of the adjacent output coupling elements may be greater than 30°, for example, to reduce or avoid the formation of ghost images.
  • the light engine ENG1 can also be provided separately from the display device 500 .
  • Light engine ENG1 may be a replaceable part of display device 500 .
  • the display device 500 may also be delivered without the light engine ENG1.
  • the display device 500 may include the image expander EPE1 and the rotation device without the need for the light engine ENG1.
  • the light engine ENG1 may be installed on the display device 500, for example at a service site or by the user USER1 himself.
  • the first light engine ENG1 may be replaced by a second light engine.
  • the vehicle-mounted head-up display device 500 may also be delivered without the light engine ENG1.
  • the optical waveguide plate SUB1 of the image expander EPE1 may be transparent, so that external light EX1 can pass through the optical waveguide plate SUB1 along the axial direction (AX1, SZ).
  • AX1, SZ axial direction
  • user USER1 views the displayed virtual image VIMG1, he can simultaneously observe the external object OBJ1 through the optical waveguide plate SUB1.
  • the external light EX1 can propagate from the external object OBJ1 through the optical waveguide plate SUB1 to the eye EYE1 of the user USER1.
  • the optical waveguide plate SUB1 may include a cutout or an opening, so that external light EX1 can propagate in the axial direction (AX1, SZ) through the cutout or opening.
  • External light EX1 may travel from the external object OBJ1 to the eye EYE1 of the user USER1 through the cutout or opening.
  • An embodiment of the present invention also provides a vehicle head-up display device, which includes the large-area display device as described above.
  • the display device 500 may be a vehicle-mounted head-up display, wherein the vehicle 1000 may be provided with the display device 500 .
  • Vehicles can be electric vehicles, internal combustion vehicles, motorcycles, trams, trains, ships, airplanes and other means of transportation.
  • the driver USER1 may need to observe driving-related information.
  • the display device 500 of the vehicle may be configured to display information about vehicle speed, battery status, vehicle motor status, and/or navigation instructions.
  • the user USER1 of the display device 500 may be a driver or a passenger of the vehicle.
  • the user USER1 can also see the real object OBJ1 and/or the environment through the display area DAR1.
  • the driver USER1 does not need to lower his head to view the instrument panel in order to observe vehicle information, but can view the information simultaneously through the windshield of the vehicle. Observe the external environment and vehicle information to avoid the need to lower your head to improve driving safety.
  • the driver's line of sight LIN1 may intersect the effective display area DAR1 of the display device 500 .
  • the rotating image extender EPE1 can provide a larger display area DAR1 by using smaller output coupling elements. This can provide user USER1 with a large Eye Box (BOX1). As long as the user's eyes EYE1 remain within the Eye Box range of the display device 500, the complete virtual image VIMG1 can be observed.
  • the rotating image expander EPE1 can provide uniform spatial intensity distribution for the output light OUT1 and provide higher image display quality. Smaller output coupling components are easier and less expensive to produce than larger output coupling components.
  • Larger display area DAR1 also facilitates display with large angular width and/or virtual image VIMG1 with large angular height ⁇ . As the display area DAR1 increases and the distance between the eye EYE1 and the image expander EPE1 is large, the user can also see the complete virtual image VIMG1, or at least most of the virtual image VIMG1.
  • the display device 500 may be mounted to the vehicle 1000 via the base BASE1.
  • the base BASE1 can be mounted to the window WIN1, dashboard or vehicle 1000 ceiling.
  • Eye EYE1 of user USER1 can receive external light EX1 from external object OBJ1.
  • external light EX1 shines on eye EYE1, user USER1 can observe external object OBJ1.
  • the external light EX1 may propagate through the window WIN1 and through the display area DAR1 of the display device 500 to the eyes EYE1 of the user USER1.
  • User USER1 can simultaneously observe the external object OBJ1 and the displayed virtual image VIMG1.
  • window WIN1 may also operate as part of display device 500, where window WIN1 may be, for example, the windshield of vehicle 1000.
  • the window WIN1 can reflect the output light OUT1 to the user EYE1, so that the user can see the displayed virtual image VIMG1 through the window WIN1.
  • the user EYE1 can simultaneously observe the external environment of the vehicle 1000 through the window WIN1.
  • the line of sight LIN1 from the external object OBJ1 to the eye EYE1 can intersect the display area DAR1.
  • the user can observe the external object OBJ1 through the window WIN1, so that the displayed virtual image VIMG1 can visually overlap with the external object OBJ1.
  • Window WIN1 can be a planar (flat) transparent window or a curved transparent window.
  • the flat window can reflect the output light OUT1 without deforming the displayed virtual image VIMG1.
  • the curved window may deform the displayed virtual image VIMG1.
  • the display device 500 should be configured to at least partially compensate for the deformation of the virtual image VIMG1.
  • the window WIN1 can simultaneously transmit the external light EX1 and reflect the output light OUT1 to the eye EYE1 of the user USER1.
  • the window WIN1 can use semi-transparent and semi-reflective glass, so that it can transmit the external light EX1 and reflect the output light OUT1 at the same time.
  • the window WIN1 may be coated with a transflective coating to increase the intensity of the reflected output light.
  • the coating may be, for example, a dielectric or metallic coating.
  • the transflective window WIN1 can also operate based on Fresnel reflection caused by the difference between the refractive index of the window and the refractive index of air. In this case, the window WIN1 does not need to be coated with a reflective coating. .
  • Embodiments of the present invention also provide a virtual image display method, which is implemented using the large-area display device as described above.

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  • Diffracting Gratings Or Hologram Optical Elements (AREA)

Abstract

一种大区域显示装置、车用抬头显示设备及虚拟图像显示方法，大区域显示装置包括产生输入图像并将输入图像转化为输入光（IN1）的光引擎（ENG1）、对输入光（IN1）进行扩展的图像扩展器（EPE1）以及旋转图像扩展器（EPE1）的驱动装置（MOTOR1）；图像扩展器（EPE1）包括光波导板（SUB1），设置有将输入光（IN1）耦合至光波导板（SUB1）上并形成波导光的输入耦合元件（DOE1）和将波导光耦合输出的第一主输出耦合元件（DOE3a）和第二主输出耦合元件（DOE3b）；输入耦合元件（DOE1）具有第一输入光栅矢量（V 1a）和第二输入光栅矢量（V 1c）；第一主输出耦合元件（DOE3a）具有第一输出光栅矢量（V 3a），第二主输出耦合元件（DOE3b）具有第二输出光栅矢量（V 3b）；第一输入光栅矢量（V 1a）和第一输出光栅矢量（V 3a）的矢量和为零，第二输入光栅矢量（V 1c）和第二输出光栅矢量（V 3b）的矢量和为零。可实现图像大区域显示，并降低装置制作难度及成本。

Description

大区域显示装置、车用抬头显示设备及虚拟图像显示方法 技术领域
本发明涉及光学显示技术领域，特别涉及大区域显示装置、车用抬头显示设备及虚拟图像显示方法。
背景技术
现有技术中的虚拟显示设备，一般包括光引擎和衍射光波导模组，其中光引擎产生输入光束，携带图像信息传播到不同方向，传播方向对应于光引擎内微显示器的不同像素。衍射光波导模组对输入光进行扩束，通过出瞳区照射到用户眼睛上，从而让用户在出瞳平面上观察到微显示器中显示的图像。
该虚拟显示设备前方有一个区域，为Eye Box，指瞳孔能获取完整图像信息的可运动空间。如果瞳孔落在Eye Box区域外，则扩展光束将无法进入眼球，从而观察不到显示的图像。
然而，Eye Box的大小受限于衍射光波导模组的外耦合元件(出瞳区)的尺寸。外耦合元件的尺寸越大，Eye Box也就越大，但大型外耦合元件的制作则是相当困难和/或昂贵。
发明内容
本发明实施例提供了一种大区域显示装置、车用抬头显示设备及虚拟图像显示方法，旨在实现图像大区域显示的同时降低显示装置的制作难度及成本。
第一方面，本发明实施例提供了一种大区域显示装置，包括用于产生输入图像并将输入图像转化为输入光的光引擎、对所述输入光进行扩展的图像扩展器以及用于旋转所述图像扩展器以产生大区域显示的驱动装置；
所述图像扩展器包括光波导板，所述光波导板上设置有用于将输入光耦合至所述光波导板上并在光栅方向形成至少一个波导光的输入耦合元件和用于将波导光耦合输出的第一主输出耦合元件和第二主输出耦合元件；
所述输入耦合元件具有第一输入光栅矢量和第二输入光栅矢量；所述第一主输出耦合元件具有第一输出光栅矢量，所述第二主输出耦合元件具有第二主输出光栅矢量；其中，所述第一输入光栅矢量和第一输出光栅矢量的矢量和为零，第二输入光栅矢量和第二输出光栅矢量的矢量和为零，所述输入耦合元件的第一输入光栅矢量和第二输入光栅矢量之间的角度为60°～120°。
第二方面，本发明实施例提供了一种车用抬头显示设备，包括如第一方面所述的大区域显示装置。
第三方面，本发明实施例提供了一种虚拟图像显示方法，采用如第一方面所述的大区域显示装置实现。
本发明实施例提供了一种大区域显示装置、车用抬头显示设备及虚拟图像显示方法，该显示装置包括用于产生输入图像并将输入图像转化为输入光的光引擎、对所述输入光进行扩展的图像扩展器以及用于旋转所述图像扩展器以产生大区域显示的驱动装置；所述图像扩展器包括光波导板，所述光波导板上设置有用于将输入光耦合至所述光波导板上并在光栅方向形成至少一个波导光的输入耦合元件和用于将波导光耦合输出的第一主输出耦合元件和第二主输出耦合元件；所述输入耦合元件具有第一输入光栅矢量和第二输入光栅矢量；所述第一主输出耦合元件具有第一输出光栅矢量，所述第二主输出耦合元件具有第二主输出光栅矢量；其中，所述第一输入光栅矢量和第一输出光栅矢量的矢量和为零，第二输入光栅矢量和第二输出光栅矢量的矢量和为零，所述输入耦合元件的第一输入光栅矢量和第二输入光栅矢量之间的角度为60°～120°。本发明实施例通过设置多个输出耦合元件，并使输入耦合元件和各输出耦合元件相对应的光栅矢量的矢量和为零，可实现图像大区域显示的同时降低显示装置的制作难度及成本。
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1a展示了显示装置的侧视图；
图1b展示了显示装置的三维图；
图1c展示了显示装置的轴向视图；
图1d展示了显示装置的轴向视图中，输出耦合元件的有效显示区域；
图2展示了显示装置的显示区域中的发光时序图；
图3a展示了通过车辆的窗户观察外部物体的示例图；
图3b展示了通过车辆的窗户接收外部光线的示例图；
图3c展示了驾驶者同时接收到透过车辆窗户的外部光线和经车辆窗户反射的输出光束示意图；
图4a～4e分别展示了光引擎产生输出光束的三维示意图；
图4f展示了观看虚拟图像的三维图；
图4g展示了虚拟图像的角宽度示意图；
图4h展示了虚拟图像的角高度示意图；
图4i展示了输入光束的波矢量示意图；
图5展示了波导光在光波导板内的传播截面图；
图6展示了衍射元件尺寸的轴向视图；
图7展示了一对输出耦合元件的轴向视图；
图8a展示了在轴向视图中，由所有光栅区域的输出光形成的一个有效显示区域示意图；
图8b展示了显示装置中的电机和光引擎的位置示意图；
图8c展示了显示装置中的电机和光引擎的另一位置示意图；
图9a展示了图像扩展器的轴向视图；
图9b展示了图像扩展器的轴向视图；
图9c展示了图9b所示的图像扩展器的立体图；
图9d展示了对于同一的图像点，所有输出耦合元件均能形成相互平行的输出光束的示意图；
图10a展示了输入耦合元件的第一输入光栅矢量V1a和第二输入光栅矢量的轴向视图；
图10b展示了输入耦合元件的四个光栅矢量的轴向视图；
图10c展示了输入耦合元件的第一输入光栅矢量V1a和第二输入光栅矢量的角度关系图；
图11a展示了输入耦合元件的四个光栅矢量及由两个相邻光栅矢量形成的四个中间光栅矢量示意图；
图11b展示了输入耦合元件的四个光栅矢量的方向，及由两个相邻光栅矢量形成的四个中间光栅矢量的方向及角度关系图；
图12a展示了输入耦合元件的两个光栅以正交方式设置的示意图；
图12b展示了输入耦合元件的二维光栅示意图；
图12c展示了输入耦合元件的两个正交光栅的排布方式的示意图；
图12d展示了输入耦合元件的两个正交光栅的排布方式的另一示意图。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通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，都属于本发明保护的范围。
应当理解，当在本说明书和所附权利要求书中使用时，术语“包括”和“包含”指示所 描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。
还应当理解，在此本发明说明书中所使用的术语仅仅是出于描述特定实施例的目的而并不意在限制本发明。如在本发明说明书和所附权利要求书中所使用的那样，除非上下文清楚地指明其它情况，否则单数形式的“一”、“一个”及“该”意在包括复数形式。
还应当进一步理解，在本发明说明书和所附权利要求书中使用的术语“和/或”是指相关联列出的项中的一个或多个的任何组合以及所有可能组合，并且包括这些组合。
下面请参见图1a和图1b，本发明实施例提供了一种大区域显示装置，包括用于产生输入图像并将输入图像转化为输入光IN1的光引擎ENG1、对所述输入光IN1进行扩展的图像扩展器EPE1以及用于旋转所述图像扩展器EPE1以产生大区域显示的驱动装置MOTOR1；
所述图像扩展器ENG1包括光波导板SUB1，所述光波导板SUB1上设置有用于将输入光IN1耦合至所述光波导板SUB1上并在光栅方向形成至少一个波导光的输入耦合元件DOE1和用于将波导光耦合输出的第一主输出耦合元件DOE3a和第二主输出耦合元件DOE3b；
所述输入耦合元件DOE1具有第一输入光栅矢量V1a和第二输入光栅矢量V1c；所述第一主输出耦合元件DOE3a具有第一输出光栅矢量V3a，所述第二主输出耦合元件DOE3b具有第二主输出光栅矢量V3b；其中，所述第一输入光栅矢量V1a和第一输出光栅矢量V3a的矢量和为零，第二输入光栅矢量V1c和第二输出光栅矢量V3b的矢量和为零，所述输入耦合元件DOE1的第一输入光栅矢量V1a和第二输入光栅矢量V1c之间的角度为60°～120°。
本实施例提供的大区域显示装置可以包括用于产生输入图像的光引擎ENG1、用于扩展光引擎ENG1出瞳图像的图像扩展器EPE1和用于旋转图像扩展器EPE1的驱动装置ENG1。其中，图像扩展器EPE1的旋转可以提供更大的发光显示区域，该区域相当于一个大的虚拟的输出耦合元件。这种实现方式使实际显示区域的面积由旋转面积决定，该面积显著大于图像扩展器EPE1的输出耦合元件的面积。旋转式的图像扩展器EPE1可以扩大光引擎的成像面积，使得显示装置可以从输出耦合元件扫过的整个区域发出输出光。这样，通过小面积的出瞳就可以达到大Eye Box的显示效果，从而使显示装置实现通过小的输出耦合元件达到大Eye Box的显示效果。
光引擎ENG1可以将输入图像转化为输入光。图像扩展器EPE1包括光波导板SUB1、通过将输入光耦合到光波导板SUB1中形成第一波导光和第二波导光的输入耦合元件DOE1、通过将第一波导光耦合出光波导板SUB1形成输出光的第一主输出耦合元件DOE3a，以及通过将第二波导光耦合出光波导板SUB1形成输出光的第二主输出耦合元件DOE3a。当输出光进入用户的眼睛时，用户便可观察到显示的虚拟图像。
输入光IN1可以包括多个输入光束，输出光OUT1可以包括多个输出光束。可以通过调整输入耦合元件DOE1的光栅矢量和输出耦合元件的光栅矢量，使得输出光束的方向与输入光束的方向相对应。同时，衍射元件的结构特征有利于图像扩展器的批量生产。
可以通过调整衍射光栅的光栅周期，使得同一图像点通过第一主输出耦合元件DOE3a形成的第一输出光束可以与通过第二主输出耦合元件DOE3b形成的第二输出光束平行。
旋转式图像扩展器EPE1可以包括多个输出耦合元件，例如第一主输出耦合元件DOE3a和第二主输出耦合元件DOE3b，以减少视觉上可检测到的闪烁效应和/或便于显示彩色图像。例如，输出耦合元件的数量NOUT可以等于4、5、6、7或8。所显示图像的闪烁频率可由NOUT乘以图像扩展器的转速fRPM给出。增加输出耦合元件的数量可提高成像过程中的闪烁频率，当该频率超过人眼的分辨率时，即可成清晰流畅的画面。或者，增加输出耦合元件的数量可以降低图像扩展器的转速fRPM。例如，降低转速fRPM可以提高旋转可靠性和/或可以减少旋转图像扩展器EPE1时产生的可听噪声。当图像的闪烁频率超过人眼的时间分辨率时，则由旋转式图像扩展器EPE1定义的整个显示区域可以被视为视觉上均匀的显示表面。
在一实施例中，所述输入耦合元件DOE1包括一个二维衍射光栅，所述二维衍射光栅均具有对应的光栅周期和光栅矢量，且光栅矢量的大小与光栅周期成反比。
在另一实施例中，所述输入耦合元件DOE1包括两个或多个具有不同衍射性能的光栅区域；
所述输入耦合元件DOE1包括两个一维衍射光栅，以在第一方向和第二方向产生衍射，且所述第一方向与第二方向正交；
所述一维衍射光栅或者二维衍射光栅均具有对应的光栅周期和光栅矢量，且光栅矢量的大小与光栅周期成反比。
所述输入耦合元件DOE1可以包括两个一维衍射光栅或一个二维衍射光栅，以便在第一方向和第二方向产生衍射。衍射光栅具有光栅周期和光栅矢量，其中，光栅矢量的大小与光栅周期成反比。二维衍射光栅可能有两个光栅周期，例如，二维衍射光栅分别具有第一输入光栅矢量V1a和第二输入光栅矢量V1c。
图像扩展器EPE1的输入耦合元件DOE1可以设置为在第一方向上形成第一波导光B1a，在第二方向上形成第二波导光B1c，且两个方向正交。例如，输入耦合元件可以在第一输入光栅矢量V1a上形成第一波导光，并在第二光输入栅矢量V1c上形成第二波导光。其中第二输入光栅矢量V1c的幅度可以等于或不等于第一输入光栅矢量V1a。
在一实施例中，第二输入光栅矢量V1c的大小可以等于第一光栅输入矢量V1a的大小。在这种情况下，图像扩展器可以包括几个输出耦合元件，以减少视觉上可检测到的闪烁效应，和/或允许降低转速。
在一实施例中，输入耦合元件DOE1可以提供四个方向的波导光，即第一方向，与第一方向正交的第二方向，与第一方向相反的第三方向，以及其与第二方向相反的第四方向。图像扩展器EPE1可以包括四个主要的输出耦合元件，以耦合出光波导板内的四个方向的波导光。图像扩展器EPE1可以包括四个主要的输出耦合元件，使得每个输出耦合元件的光栅矢量可以与输入耦合元件DOE1的光栅矢量相反。输出耦合元件可以设置在输入耦合元件周围。
输入耦合光栅将输入光通过衍射耦合到光波导板SUB1中的能力可能取决于输入光束的入射角、波长，输入耦合光栅的光栅周期以及光波导板SUB1的折射率。输入耦合光栅将输入光耦合到光波导板中SUB1的能力可能会限制所显示图像的角宽度。
在一实施例中，输入耦合元件DOE1可以具有两个不同的光栅周期，例如第一光栅周期和第二光栅周期，以优化多种波段的色彩均匀性。其中，第一光栅周期可以允许显示图像的第一颜色分量(例如绿色)。第二个不同的光栅周期(例如第二光栅周期)可以允许显示图像的第二颜色分量(例如红色)。可以选择第一光栅周期以优化第一波长的输入耦合、内传导和/或输出耦合。可以选择第二个不同的光栅周期，以优化第二个波长的输入耦合、内传导和/或输出耦合。
第二输入光栅矢量V1c的幅度可以不同于第一输入光栅矢量V1a。第二输入光栅矢量V1c的幅度可以不同于第一输入光栅矢量V1a，以利于彩色图像的显示。
在一实施例中，光引擎ENG1和显示装置500可以单独交付，其中光引擎ENG1可以与显示装置500组合，例如由零售商或由最终用户自行组装。在该实施例中，光引擎ENG1可以是整个显示装置500的可替换部分。
在一实施例中，显示装置500以是车载抬头显示器。该显示装置500可用作车载抬头显示器。显示装置500的大Eye Box为用户提供了更大的可显示区域，例如当车辆在道路上行驶并且用户的头部根据行驶产生震动时，仍然可以清楚地观看到虚拟图像。
在一实施例中，可以通过使用光刻技术来生产输出耦合元件。例如，可以通过电子束光刻机来制作衍射光栅的压印模板，并利用纳米压印技术进行转录，从而大批量地生产衍射光栅元件。然而压印模板尺寸的增大会显着提高制作成本，而通过旋转图像扩展器便可提供扩大的显示区域而无需增大压印模板的尺寸。
显示装置500可以包括产生输入光IN1的光引擎ENG1、通过扩展输入光IN1形成输出光OUT1的图像扩展器EPE1、以及通过旋转图像扩展器ENG1来放大显示区域DAR1的驱动装置ENG1。
当输出光OUT1照射到用户的眼睛EYE1上时，用户USER1可以通过显示装置500观察到显示的虚拟图像VIMG1。
输入光IN1可以包括在不同方向上传播的多个子输入光束。其中，输入光IN1的每一子输入光束可对应于输入图像IMG0的不同像素点。
输出光OUT1可以包括在不同方向上传播的多个子输出光束。其中，输出光OUT1可以包括对应于虚像VIMG1的不同点的多个子输出光束。图像扩展器EPE1可以将输入光IN1扩展成输出光OUT1，并使得输出光OUT1的每一个子输出光束的光束方向和强度对应于输入图像IMG0的不同像素点。特别地，图像扩展器EPE1可以通过衍射来扩展输入光束来形成输出光束，使得每个子输出光束可以在与相应的子输入光束相同的方向上传播。因此，显示的虚拟图像VIMG1可以代表输入图像IMG0。
输入光IN1的光束可以对应于显示图像的单个像素点(P0)。在图像扩展器EPE1的作用下，输出光束的方向(k3,P0,R)平行于对应的输入光束的方向(k0,P0,R)。且对于不同像素点的光束可以沿不同的方向传播。不同像素点的传播方向如图4a～4i所示。
光引擎ENG1可以产生对应于输入图像IMG0的输入光IN1，同时输入光IN1可以包括对应于输入图像IMG0的不同像素点在不同方向上传播的多个子输入光束。光引擎ENG1可以包括显示器DISP1和准直光学器件LNS1以形成输入光束。
图像扩展器EPE1可以包括光波导板SUB1，光波导板SUB1可以包括输入耦合元件DOE1和一个或多个输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d。输入耦合元件DOE1可以将输入光IN1耦合到光波导板SUB1中，其中输入光IN1的照射面积与输入耦合元件DOE1重叠。同时，输入耦合元件DOE1的中心点也需与旋转轴线AX1共轴。
元件DOE1、DOE3a、DOE3b、DOE3c、DOE3d可以是衍射元件，其中每个衍射元件可以包括一个或多个衍射光栅，其中衍射光栅可以设置在光波导板SUB1的第一和/或第二表面上。输入耦合元件DOE1可以通过衍射将输入光IN1耦合进光波导板SUB1来形成波导光B1a、B1b。波导光B1a、B1b在波导板SUB1中利用全反射进行传播。
输出耦合元件DOE3a、DOE3b可以通过衍射将波导光B1a、B1b耦合出光波导板SUB1并形成输出光OUT1。输出耦合元件DOE3a、DOE3b可作为第一对输出耦合元件，且位于输入耦合元件DOE1的相对侧。
输出耦合元件DOE3c、DOE3d可以通过衍射将波导光B1c、B1d耦合出光波导板SUB1并形成输出光OUT1，见图9c。输出耦合元件DOE3c、DOE3d可作为第二对输出耦合元件，且位于输入耦合元件DOE1的相对侧，与第一对输出耦合元件呈正交关系。
在一实施例中，第一对输出耦合元件DOE3a、DOE3b可以优化显示图像的第一颜色分量；第二对输出耦合元件DOE3c、DOE3d可以优化显示图像的第二颜色分量。
图像扩展器EPE1可以作为显示装置500的出瞳，以便将眼睛保持在相对于显示装置500合适的位置上。
在一实施例中，所述驱动装置MOTOR1带动图像扩展器EPE1围绕一旋转轴AX1且相对于一固定基座BASE1旋转和/或振动，其中，所述输入耦合元件DOE1与所述旋转轴AX1的间隔小于所述光波导板直径的5％；
所述光引擎ENG1通过一保护盖502与所述固定基座BASE1机械连接，所述保护盖502为透明或半透明保护盖。
图像扩展器EPE1可以设置为相对于固定基座BASE1旋转。所述显示装置500可以通过基座BASE1安装到例如车辆1000上。例如，显示装置500可以经由一个或多个接头FIX1安装到车辆1000上，其中接头可采用粘合接头和/或螺纹接头。
光引擎ENG1可以固定地安装到基座BASE1中并保持相对静止。图像扩展器EPE1可设置为相对于固定基座BASE1旋转和/或振动。
显示装置500可以包括驱动装置MOTOR1，以带动图像扩展器EPE1相对于固定基座BASE1旋转和/或振动。其中驱动装置MOTOR1可以是电机或气动涡轮机，并可以通过例如 保护盖502和/或固定件直接或间接地连接到基座BASE1中。驱动装置MOTOR1可以围绕旋转轴AX1带动图像扩展器EPE1以角速度ω1旋转，该角速度对应于旋转速度fRPM。
光引擎ENG1可以通过例如保护盖502机械地连接到基座BASE1中。保护盖502可以是透明的或半透明的。例如，透明盖502可以包括透明玻璃或塑料，半透明盖502可以包括具有透视特性的网。保护盖502还可以防止用户意外接触旋转中的图像扩展器EPE1。
光引擎ENG1也可以通过连接结构连接到基座BASE1中。在一实施例中，连接结构可以是开放结构，因为并非总是需要保护旋转中的图像扩展器EPE1的后侧。
符号LEYE1表示图像扩展器EPE1与用户眼睛EYE1之间的距离。当使用显示装置500作为车辆1000的抬头显示器时，距离LEYE1可以在例如0.1m到1.0m的范围内。
SX、SY和SZ为正交坐标系。光波导板SUB1可以平行于由方向SX和SY定义的平面。
输入耦合元件DOE1可以接收输入光IN1，输出耦合元件可以提供输出光OUT1。输入光IN1可以包括在不同方向上传播的多个子输入光束。输出光OUT1可以包括由输入光IN1的子输入光束(B0)形成的多个扩展光束(B3)。
图像扩展器EPE1通过扩展输入光IN1形成输出光OUT1。其中，输出光OUT1的光束宽度wOUT1大于输入光IN1的光束宽度wIN1。图像扩展器EPE1可以在输入耦合元件DOE1的光栅矢量(V1)方向上扩展输入光IN1。当光栅矢量(V1)平行于水平方向(SX)时，图像扩展器EPE1可以在水平方向(SX)上扩展输入光IN1；当光栅矢量(V1)平行于垂直方向(SY)时，图像扩展器EPE1可以在垂直方向(SY)上扩展输入光IN1。
在旋转过程中，图像扩展器EPE1可以逐步扩展输出光OUT1中子输出光束(B3)的水平截面宽度wOUT1和垂直截面高度hOUT1。因此，图像扩展器EPE1在旋转过程中可有效地在二维方向(例如，在方向SX和在方向SY)上扩展输入光IN1，该扩展过程也可称为出瞳扩展。图像扩展器EPE1也可以称为光束扩展器或出瞳扩展器。
输入耦合元件DOE1可以通过将输入光IN1耦合进光波导板SUB1中来形成波导光B1或B1a、B1b。波导光B1、B1a、B1b可以在平面光波导板SUB1内传播，并通过全内反射被限制在光波导板SUB1上。
参考图1c和图1d，图像扩展器(EPE1)可以在驱动装置(MOTOR1)的驱动下绕旋转轴AX1旋转，其中圆形路径PATH1为图像扩展器(EPE1)多个输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d的旋转轨迹，并生成大面积显示区域DAR1。假设显示区域中任一点POINT1相对于底座BASE1的坐标为(x1,y1)，在图像扩展器(EPE1)旋转过程中，输出耦合元件会周期性地经过点POINT1，使点POINT1以相同的周期通过脉冲的方式发射输出光OUT1。我们可以通过提高旋转速度(fRPM)来降低由脉冲式发光产生的闪烁效果。
当输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d扫过所述点时，显示区域DAR1的每个点均可以通过脉冲方式时序地发射输出光OUT1，从而使整个显示区域DAR1同样以脉冲的方式发出输出光OUT1。
其中，符号wEPE1表示图像扩展器EPE1的宽度(在图像扩展器EPE1停止旋转并且输出耦合元件DOE3a与水平方向SX对齐的情况下)，图像扩展器EPE1基本上可以是圆形的，并且图像扩展器EPE1的直径可以等于宽度wEPE1。
wDAR1表示显示区域DAR1的宽度，hDAR1表示显示区域DAR1的高度，ADAR1表示显示区域DAR1的有效表面积。ADOE3表示输出耦合元件DOE3(或DOE3a)的表面积。显示区域DAR1的有效表面积ADAR1可以大于输出耦合元件DOE3(或DOE3a)的表面积ADOE3。
在一实施例中，图像扩展器EPE1和/或驱动装置MOTOR1可以遮挡显示区域DAR1的中心区域，使得圆形显示区域DAR1具有暗中心。其中，显示区域DAR1可以是由内边界BND2和外边界BND1限定的环形区域，内边界BND2可以具有半径r2DAR1。外边界BND1可以具有半径r1DAR1。边界BND1、BND2与旋转轴AX1共轴。
在一实施例中，图像扩展器EPE1的中心区域也可以提供输出光OUT1，使得圆形显示区域DAR1不具有暗中心(图8a)。
例如，外边界BND1的半径r1DAR1可以在4cm到25cm的范围内。图像扩展器EPE1的宽度wEPE1可以在8cm到50cm的范围内。显示区域DAR1的表面积ADAR1可以在100cm2至2000cm2。
其中，w1表示输入耦合元件DOE1的宽度，h1表示输入耦合元件DOE1的高度。wIN1表示输入光束(IN1)的横截面宽度，hIN1表示输入光束(IN1)的横截面高度。w3表示输出耦合元件DOE3a的宽度，h3表示输出耦合元件DOE3a的高度。wOUT1表示输出光束(OUT1)的横截面宽度，hOUT1表示输出光束(OUT1)的横截面高度。在一实施例中，输出光OUT1的横截面尺寸可以由输出耦合元件DOE3a的尺寸限定，其中宽度wOUT1基本上等于宽度w3和/或高度hOUT1可以基本上等于高度h3。
图像扩展器EPE1可以相对于基座BASE1旋转。其中，光引擎ENG1的光轴AX0可以与图像扩展器EPE1的旋转轴AX1共轴，输入耦合元件DOE1可以与图像扩展器EPE1的旋转轴AX1共轴。
在一实施例中，所述驱动装置MOTOR1以固定转速旋转所述图像扩展器EPE1，所述固定转速为每秒5至200转。
驱动装置MOTOR1可以设置为以转速fRPM旋转光波导板SUB1，其转速可以在每秒5至200转的范围内。
例如，驱动装置MOTOR1可以带动图像扩展器EPE1旋转，使得图像扩展器EPE1的转速fRPM大于或等于30转/秒。此时，用户便难以在视觉上检测到显示图像VIMG1的闪烁。
例如，驱动装置MOTOR1可以带动图像扩展器EPE1旋转，使得图像扩展器EPE1的转速fRPM大于或等于60转/秒。此时，用户可能更难以视觉检测显示图像VIMG1的闪烁。
在一实施例中，图像扩展器EPE1可由驱动装置MOTOR1的一个或多个轴承可旋转地支撑。
驱动装置MOTOR1和光引擎ENG1可以在图像扩展器EPE1的不同侧(见图1a)或在图像扩展器EPE1的同一侧(见图8b、8c)。例如，驱动装置MOTOR1可以具有中央开口(HOL1)，以允许将驱动装置MOTOR1和光引擎ENG1定位在图像扩展器EPE1的同一侧。
在一实施例中，图像扩展器EPE1可以作为MOTOR1的旋转部件操作。例如，图像扩展器EPE1可包括磁体或线圈以产生旋转所需的力。图像扩展器EPE1还可以由位于边缘处的轴承或由位于旋转轴线AX1处的滚针轴承可旋转地支撑。
图2展示了显示区域DAR1的任一点(例如POINT1)的局部强度IPOINT1在显示虚拟图像VIMG1时的时序图。当图像扩张器EPE1旋转时，点POINT1可看作以脉冲的方式向眼睛EYE1发射光束。在该示例中，图像扩展器EPE1包括四个输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d。当点POINT1与输出耦合元件DOE3a、DOE3b、DOE3c或DOE3d重叠时，点POINT1的强度达到最大值IMAX；当点POINT1不与任意输出耦合元件重叠时，点POINT1的强度为零。TROT表示图像扩展器EPE1旋转一周的时间段，其中TROT＝1/fRPM。TON表示点POINT1与任意输出耦合元件重叠时的时间段，同时也表示当任意输出耦合元件扫过所述点POINT1时，从点POINT1发出的光脉冲的持续时间。TBLANK表示点POINT1不与任意输出耦合元件重合时的时间段。点POINT1在时间t1a，t'1a之间、时间t2a，t'2a之间、时间t3a，t'3a之间以及时间t4a，t'4a之间位于输出耦合元件DOE3a的区域内；点POINT1在时间t1b，t'1b之间、时间t2b，t'2b之间以及时间t3b，t'3b之间位于输出耦合元件DOE3b的区域内；点POINT1在时间t1c，t'1c之间、时间t2c，t'2c之间、时间t3c，t'3c之间以及时间t4c，t'4c之间位于输出耦合元件DOE3c的区域内；点POINT1在时间t1d，t'1d之间、时间t2d，t'2d之间以及时间t3d，t'3d之间位于输出耦合元件DOE3d的区域内。
图像扩展器EPE1可以例如沿图1所示的方向旋转，其中显示区域DAR1的所述点POINT1可以对于任意输出耦合元件在同一显示位置上重叠，例如按以下顺序出现：DOE3a，DOE3d，DOE3b，DOE3c，DOE3a，DOE3d，DOE3b，DOE3c,...。
光引擎ENG1可同时投影红光、绿光和蓝光，以显示彩色虚拟图像VIMG1，此时图像扩 展器EPE1需设置为可显示三种波段；光引擎ENG1也可设置为仅投射一种颜色(例如，红色、绿色或蓝色)，以显示单色虚拟图像VIMG1，此时图像扩展器EPE1需设置为可现实对应的色光。
参考图4a至4e，图像扩展器EPE1可以通过扩展由光引擎ENG1产生的输入光IN1来形成输出光OUT1。
光引擎ENG1可以包括微显示器DISP1和准直光学器件LNS1。其中，微显示器DISP1可用于显示输入图像IMG0，准直光学器件LNS1可用于将输入图像IMG0转换为输入光IN1。
输入图像IMG0可以包括中心点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可以是单色图像，通过调制激光或调制一个或多个发光二极管来形成单色图像IMG0。输入图像IMG0也可以是彩色图像，例如RGB图像，其可以包括红色局部图像、绿色局部图像和蓝色局部图像。每个像点可以提供例如红光、绿光或蓝光。
光引擎ENG1可以提供输入光IN1，其可以包括多个基本准直的光束(B0)。例如，每个红色光束可以在不同的方向上传播并且可以对应于输入图像IMG0的不同点。其中，每个光束可以具有不同的颜色，例如，下标“R”可以指代红色。例如，红色光束B0P0,R可以对应于中心像点P0，并且可以在波矢量k0P0,R的方向上传播。
红色光束B0P1,R可以对应于像点P1，并且可以在波矢量k0P1,R方向上传播；红色光束B0P2,R可以对应于像点P2，并且可以在波矢量k0P2,R的方向上传播；红色光束B0P3,R可以对应于像点P3，并且可以在波矢量k0P3,R的方向上传播；红色光束B0P4,R可以对应于像点P4，并且可以在波矢量k0P4,R的方向上传播。
此外，蓝色光束(B0P1,B)可以对应于像点P1，并且可以在波矢量(k0P1,B)的方向上传播。
例如，可以形成输入光IN1，使得对应于输入图像IMG0的第一角点P1的蓝色光束(B0P1,B)的传播方向(k0P1,B)可以与红色光束(B0P1,R)的传播方向(k0P1,R)平行；例如，可以形成输入光IN1，使得对应于输入图像IMG0的第二角点P2的蓝色光束(B0P2,B)的传播方向(k0P2,B)可以与红色光束(B0P2,R)的传播方向(k0P2,R)平行。
光的波矢量(k)可以定义为所述光的传播方向，其大小由2π/λ给出，其中λ是所述光的波长。
中心点P0的光B0P0,R可沿轴向(k0P0,R)传播。轴向(k0P0,R)可以与光引擎ENG1的光轴(AX0)平行。
参考图4f，输出光OUT1可以包括多个子输出光束B3P1,R、B3P2,R、...，它们可以对应于显示的虚拟图像VIMG1的点P1'、P2'、…。例如，沿波矢量k3P0,R的方向传播的红色光束B3P0,R可以对应于图像VIMG1的点P0'；在波向量k3P1,R的方向上传播的红色光束B3P1,R可以对应于图像VIMG1的点P1'；在波向量k3P2,R的方向上传播的红色光束B3P2,R可以对应于图像VIMG1的点P2'；在波矢量k3P3,R的方向上传播的红色光束B3P3,R可以对应于点P3'。在波矢量k3P4,R的方向上传播的红色光束B3P4,R可以对应于点P4'。
图像扩展器EPE1可以通过扩展光引擎ENG1的出瞳来形成输出光OUT1。输出光OUT1可以包括多个子输出光束，其分别对应于所显示的虚拟图像VIMG1的每个像点。输出光OUT1可以照射到观察者的眼睛EYE1上，使得观察者看到所显示的虚拟图像VIMG1。
所显示的虚拟图像VIMG1可具有中心点P0'和四个角点P1'、P2'、P3'、P4'。输入光IN1可包括对应于输入图像IMG0的点P0、P1、P2、P3、P4的多个部分光束。在图像扩展器EPE1中，可以通过衍射和全内反射将所述输入图像IMG0的点P0对应的子输入光转换为所显示的虚拟图像VIMG1的点P0'对应的子输出光。输入光IN1会在输入耦合元件DOE1的作用下产生衍射，将输入光IN1耦合进光波导板SUB1形成波导光B1、B1a、B1b，该波导光包括输入图像IMG0的中心点P0的光信息。波导光B1、B1a、B1b分别在对应的输出耦合元件DOE3、DOE3a、DOE3b的作用下，通过衍射耦合出光波导板SUB1，形成输出光OUT1，使 得输出光OUT1包含中心点P0的全部光信息。
图像扩展器EPE1可以通过衍射和全内反射将点P1、P2、P3、P4转换成点P1'、P2'、P3'、P4'。
图像扩展器EPE1可以扩展输入光IN1，使得每个输出光束B3P1,R，B3P2,R，B3P3,R，...可以在与相应输入光束B0P1,R，B0P2,R，B0P3,R，...在相同的方向上传播。例如，图像扩展器EPE1可以将输入光束B0P1,R转换成输出光束B3P1,R，使得输出光束B3P1,R在与输入光束B0P1,R相同的方向上传播，同时光束B0P1,R、B3P1,R对应于输入图像IMG0的相同点P1。例如，图像扩展器EPE1可以将输入光束B0P2,R转换成输出光束B3P2,R，使得输出光束B3P2,R在与输入光束B0P2,R相同的方向上传播，同时光束B0P2,R、B3P2,R可对应于输入图像IMG0的相同点P2。
图像扩展器EPE1可以使波矢k3P1,R与输入光IN1中的点P1的红光的波矢k0P1,R平行；波矢k3P0,R可以与点P0的波矢k0P0,R平行；波矢k3P2,R可以与点P2的波矢k0P2,R平行；波矢k3P3,R可以与点P3的波矢k0P3,R平行；波矢k3P4,R可以与点P4的波矢k0P4,R平行。
参考图4g和4h，显示的虚拟图像VIMG1具有角宽和角高Δθ。
所显示的虚拟图像VIMG1可以具有左侧的第一角点P1'和右侧的第二角点P2'，其中虚拟图像VIMG1的角宽度可以等于角点P1'、P2'的波向量k3P1,R、k3P2,R之间的水平角。
所显示的虚拟图像VIMG1可以具有上角点P1'和下角点P3'，其中虚拟图像VIMG1的角高Δθ可以等于角点P1'、P3'的波矢k3P1,R、k3P3,R之间的垂直角。
波矢量的方向可以通过例如方向角和θ来指定。角度可以表示波矢量和参考平面REF1之间的角度，其中参考平面REF1由SZ和SY定义；角度θ可表示波矢量和参考平面REF2之间的角度，其中参考平面REF2由SZ和SX定义。
参考图4i，输入光IN1可以包括红光(R)、绿光(G)和/或蓝光(B)。例如，输入光IN1可以包括蓝色输入光束，其波矢可以为k0P0,B，k0P1,B，k0P2,B，k0P3,B，k0P4,B，分别对应于图像IMG0的蓝色像点P0，P1，P2，P3，P4。图像扩展器EPE1可以将蓝色输入光束转换成蓝色输出光束，使得每个蓝色输出光束的波矢与对应的蓝色输入光束的波矢平行。
参考图5，光引擎ENG1可以导入输入图像IMG0并且可以将输入图像IMG0转换为输入光IN1的多个子输入光束。由光引擎ENG1提供的一个或多个子输入光束可以作为输入光IN1通过输入耦合元件DOE1耦合到图像扩展器EPE1内。
输入图像IMG0可以表示例如图形、文本、视频等信息。光引擎ENG1可以生成静止图像和/或视频，可以从数字图像生成真实的主图像IMG0，也可以从互联网服务器或从智能手机接收一个或多个数字图像。
图像扩展器EPE1可以将来自光引擎ENG1的虚拟图像内容传送到用户眼睛EYE1的前方。图像扩展器EPE1可以扩张视瞳，从而扩大Eye Box。
光引擎ENG1可包括微显示器DISP1以产生输入图像IMG0。微显示器DISP1可以包括发光的二维像素阵列。光引擎ENG1可以包括例如一个或多个发光二极管(LED)。微显示器DISP1可以包括例如硅基液晶(LCOS)、液晶显示器(LCD)、数字微镜阵列(DMD)、微米发光二极管(Micro LED)等显示器件。位显示器DISP1可以以例如1280×720(HD)的分辨率生成输入图像IMG0，或是以1920×1080(全高清)的分辨率生成输入图像IMG0，也可以以3840×2160(4K UHD)的分辨率生成输入图像IMG0。其中，输入图像IMG0可以包括多个图像点P0、P1、P2、...。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不同方向的准直光束。微显示器DISP1的中心和准直光学器件LNS1的中心可以一起定义光引擎ENG1的光轴AX0。
光波导板SUB1可以具有第一主表面SRF1和第二主表面SRF2。表面SRF1、SRF2应高度平行于由方向SX和SY限定的平面。
光波导板SUB1可以包括或基本上由透明固体材料组成。波导板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DOE1、DOE3a、DOE3b、DOE3c、DOE3d可以例如通过模制、压花和/或蚀刻形成。衍射光学元件DOE1、DOE3a、DOE3b、 DOE3c、DOE3d可以例如由一个或多个表面浮雕光栅或由一个或多个体全息光栅实现。
光波导板SUB1的厚度为tSUB1。波导板包括平面波导芯。在一实施例中，个波导板SUB1可以包括一个或多个包覆层、一个或多个保护层和/或一个或多个机械支撑层。厚度tSUB1也可以指光波导板SUB1的平面波导芯的厚度。
参考图6，每个元件DOE1、DOE3a、DOE3b、DOE3c、DOE3d可以包括一个或多个衍射光栅以产生衍射光。
例如，输入耦合元件DOE1可以包括一个或多个光栅G1a。例如，输出耦合元件DOE3a可以包括光栅G3a。例如，输出耦合元件DOE3b可以包括光栅G3b。
衍射光栅的光栅周期(d)和衍射光栅的光栅方向(β)可以由所述衍射光栅的光栅矢量V指定。衍射光栅包括多个作为衍射线的衍射特征(F1a、F3a)，衍射特征可以是例如微观脊或凹槽，还可以是微观突起(或凹陷)，其中相邻的突起(或凹陷)行可以充当衍射线。光栅矢量V的取值为2π/d，方向垂直于衍射光栅的衍射线，其中d为光栅周期。光栅周期可以是光栅的连续衍射特征之间的长度，或是单位长度除以位于所述单位长度内的衍射特征的数量。输入耦合元件DOE1的光栅周期d1a可以例如在330nm到450nm的范围内。光栅周期d的最佳值取决于光波导板SUB1对波长λ的折射率。
输入耦合元件DOE1的光栅矢量可以为V1a，通过对输入光IN1的衍射形成第一波导光B1a。输入耦合元件DOE1具有衍射光栅G1a，其衍射特征为F1a，光栅周期为d1a，光栅方向为β1a且相对于参考方向SX的取向。光栅G1a的衍射特征可以是例如微观脊或微观突起。
输出耦合元件DOE3a的光栅矢量可以为V3a，通过衍射将波导光B1a耦合到光波导板SUB1之外。输出耦合元件DOE3a具有衍射光栅G3a，其衍射特征为F3a，光栅周期为d3a，光栅方向为β3a且相对于参考方向SX的取向。光栅G3a的衍射特征可以是例如微观脊或微观突起。
光栅矢量V1a的方向为β1a，幅度为2π/d1a；光栅矢量V3a的方向为β3a，幅度为2π/d3a。光栅矢量的方向(β)可以由所述矢量和参考方向(例如方向SX)之间的角度来指定。
可以选择光学元件的衍射光栅的光栅周期(d)和光栅方向(β)，使得输出光OUT1中主光线的传播方向(k3P0,R)与输入光IN1中主光线的传播方向(k0P0,R)相同。
可以选择光学元件DOE1、DOE3a、DOE3b、DOE3c、DOE3d的衍射光栅的光栅周期(d)和光栅方向(β)，使得输出光OUT1的每个子输出光束的传播方向可以平行于输入光IN1对应的子输入光束的传播方向。
参考图7，所述输出耦合元件DOE3a、DOE3b可共同构成第一对输出耦合元件；所述输出耦合元件DOE3c、DOE3d可共同构成第二对输出耦合元件。
图像扩展器EPE1可以相对于旋转轴AX1保持机械平衡，从而最大限度地减少或消除由图像扩展器EPE1的旋转引起的机械振动。
图像扩展器EPE1可以是静态平衡的，使得图像扩展器EPE1的重点落在旋转轴AX1上；图像扩展器EPE1也可以是动态平衡的，以便围绕轴AX1旋转不会产生任何离心力。
参考图8a～8c，除了输出耦合元件DOE3a、DO3b、DOE3c、DO3d之外，输入耦合元件DOE1也可以提供输出光OUT1。通过将波导光B1耦合出光波导板SUB1，并允许输入光IN1的一部分直接透过图像扩展器EPE1，以提供连续的圆形显示区域DAR1，使得显示区域DAR1不具有暗中心。其中，输入耦合元件DOE1可以形成输出光OUT1的中心部分OUT1C。
直接透射的输入光IN1强度较高，并且透射输入光IN1可能对用户的眼睛EYE1造成眩目效果。显示装置500可以通过设置过滤器FIL1以衰减输出光OUT1C的强度，使得输入耦合元件DOE1提供的输出光OUT1C的强度基本上等于输出耦合元件DOE3a、DOE3b提供的输出光OUT1的有效强度。过滤器FIL1可以通过在图像扩展器EPE1的主表面SRF2上沉积半反射层和/或吸收层来实现。
驱动装置MOTOR1可以是电机。驱动装置MOTOR1和光引擎ENG1可以设置在图像扩展器EPE1的同一侧。显示装置500可包括数据传输线BUS1，其用于通过驱动装置MOTOR1 将图像数据DATA1传输至光引擎ENG1。
参考图8b，驱动装置MOTOR1可以由内部旋转转子ROTO1和外部静止定子STAT1组成。其中，定子STAT1相对于基座BASE1静止，转子ROTO1相对于基座BASE1旋转。驱动装置MOTOR1和光引擎ENG1可以位于图像扩展器EPE1的后侧，使驱动装置MOTOR1不会阻挡显示区域DAR1的中央区域。
显示装置500可包括数据传输线BUS1，其用于通过驱动装置MOTOR1将图像数据DATA1传输至光引擎ENG1中的微显示器DISP1上。显示装置500可以包括用于传输图像数据DATA1的引线FEED1，其中引线FEED1可以包括数据传输线BUS1，其能穿过驱动装置MOTOR1的中心开口HOL1连接光引擎ENG1。中央开口HOL1还可容纳用于机械支撑光引擎ENG1的固定支撑元件CE1。
定子STAT1可以直接或间接固定到基座BASE1。定子STAT1可以支撑微显示器DISP1，使得显示器DISP1相对于基座BASE1静止。固定支撑元件CE1可以经由驱动装置MOTOR1的中心开口HOL1将光引擎ENG1机械连接到基座BASE1上，同时固定支撑元件CE1可以直接或间接连接到基座BASE1上。固定支撑元件CE1可以使显示器DISP1相对于底座BASE1保持静止。例如，固定支撑元件CE1可以是将光引擎ENG1连接到基座BASE1的固定轴。传输线BUS1可以是电和/或光数据传输线。第二旋转支撑元件CE2可以通过将转子ROTO1机械连接到图像扩展器EPE1上，使得转子ROT1的旋转运动传递到图像扩展器EPE1。第二旋转支撑元件CE2可以部分或完全围绕光引擎ENG1。
参考图8c，驱动装置MOTOR1可以由外部旋转转子ROTO1和内部静止定子STAT1组成。其中，定子STAT1相对于基座BASE1静止，转子ROTO1相对于基座BASE1旋转。驱动装置MOTOR1和光引擎ENG1可以位于图像扩展器EPE1的后侧，使驱动装置MOTOR1不会阻挡显示区域DAR1的中央区域。
显示装置500可包括数据传输线BUS1，其用于通过驱动装置MOTOR1将图像数据DATA1传输至光引擎ENG1中的微显示器DISP1上。显示装置500可以包括用于传输图像数据DATA1的引线FEED1，其中引线FEED1可以包括数据传输线BUS1，其能穿过驱动装置MOTOR1的中心开口HOL1连接光引擎ENG1。中央开口HOL1还可容纳用于机械支撑光引擎ENG1的固定支撑元件CE1。
定子STAT1可以直接或间接固定到基座BASE1。定子STAT1可以支撑微显示器DISP1，使得显示器DISP1相对于基座BASE1静止。固定支撑元件CE1可以经由驱动装置MOTOR1的中心开口HOL1将光引擎ENG1机械连接到基座BASE1上，同时固定支撑元件CE1可以直接或间接连接到基座BASE1上。固定支撑元件CE1可以使显示器DISP1相对于底座BASE1保持静止。例如，固定支撑元件CE1可以是将光引擎ENG1连接到基座BASE1的固定轴。传输线BUS1可以是电和/或光数据传输线。第二旋转支撑元件CE2可以通过将转子ROTO1机械连接到图像扩展器EPE1上，使得转子ROT1的旋转运动传递到图像扩展器EPE1。第二旋转支撑元件CE2可以部分或完全围绕光引擎ENG1。
在一实施例中，所述光波导板SUB1上还设置有第三主输出耦合元件DOE3c，所述第三主输出耦合元件DOE3c具有第三输出光栅矢量，所述第三输入光栅矢量和第三输出光栅矢量的矢量和为零；所述输入耦合元件DOE1位于第一主输出耦合元件DOE3a和第三主输出耦合元件DOE3c之间；
和/或，所述光波导板上SUB1还设置有第四主输出耦合元件DOE3d，所述第四主输出耦合元件DOE3d具有第四输出光栅矢量，所述第四输入光栅矢量和第四输出光栅矢量的矢量和为零；所述输入耦合元件DOE1位于第二主输出耦合元件DOE3d和第四主输出耦合元件DOE3d之间。
参考图9a，图像扩展器EPE1可以包括四个主要的输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d。其中，输入耦合元件DOE1可以位于第一主输出耦合元件DOE3a和第三输出耦合元件DOE3b之间，同时也位于第二主输出耦合元件DOE3c和第四输出耦合元件DOE3d之间。
输入耦合元件DOE1可以为四个方向提供波导光B1a，B1b，B1c，B1d，即第一方向，第一方向的反向和与第一方向正交的两个方向。
第一主输出耦合元件DOE3a可以将第一波导光B1通过衍射耦合出光波导板SUB1。第二主输出耦合元件DOE3b可以将第二波导光B2通过衍射耦合出光波导板SUB1。第三输出耦合元件DOE3c可以将第三波导光B3通过衍射耦合出光波导板SUB1。第四输出耦合元件DOE3d可以将第四波导光B4通过衍射耦合出光波导板SUB1。
在一实施例中，所述输入耦合元件DOE1形成的波导光包括中间波导光(如图中的B1e等)；
所述光波导板SUB1还设置有至少一个用于将中间波导光耦合输出的中间输出元件(如图中的DOE3e等)，所述中间输出元件位于第一主输出耦合元件DOE3a和第二主输出耦合元件DOE3b之间，所述中间输出元件具有中间输出光栅矢量，并使得第一输入光栅矢量V1a、第二输入光栅矢量V1c和中间输出光栅矢量的矢量和为零。
参考图9b，图像扩展器EPE1可以包括一个或多个中间输出耦合元件DOE3e、DOE3f、DOE3g、DOE3h。图像扩展器EPE1可以包括一个或多个中间输出耦合元件DOE3e、DOE3f、DOE3g、DOE3h以取代或包括一个或多个主输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d。
输入耦合元件DOE1可以在输入耦合元件DOE1的光栅矢量V1a，V1b，V1c，V1d指定的主要方向上形成波导光B1a，B1b，B1c，B1d。此外，输入耦合元件DOE1还可以在相邻的两个光栅矢量指定的方向上形成中间波导光B1e、B1f、B1g、B1h。
中间输出耦合元件DOE3e、DOE3f、DOE3g、DOE3h可以将中间波导光B1e、B1f、B1g、B1h耦合出光波导板SUB1。
主输出耦合元件DOE3a，DOE3b，DOE3c，DOE3d和中间输出耦合元件DOE3e，DOE3f，DOE3g，DOE3h可以设置在输入耦合元件DOE1的周围。
中间输出耦合元件DOE3e可以位于主输出耦合元件DOE3a，DOE3c之间。中间输出耦合元件DOE3f可以位于主输出耦合元件DOE3b，DOE3d之间。中间输出耦合元件DOE3g可以位于主输出耦合元件DOE3b，DOE3c之间。中间输出耦合元件DOE3h可以位于主输出耦合元件DOE3a，DOE3d之间。
输入耦合元件DOE1可以位于中间输出耦合元件DOE3e，DOE3f之间。输入耦合元件DOE1可以位于中间输出耦合元件DOE3g，DOE3h之间。
参考图9c，每个输出耦合元件可以形成输出光OUT1的一部分。输出耦合元件DOE3a可以通过将波导光B1通过衍射耦合出光波导板SUB1来形成输出光OUT1中的B3a。所述输出耦合元件DOE3b可以通过衍射波导光B1b形成输出光OUT1中的B3b。所述输出耦合元件DOE3c可以通过衍射波导光B1c形成输出光OUT1中的B3c。所述输出耦合元件DOE3d可以通过衍射波导光B1d形成输出光OUT1中的B3d。
所述中间输出耦合元件DOE3e可以通过衍射波导光B1e形成输出光OUT1中的B3e。所述中间输出耦合元件DOE3f可以通过衍射波导光B1f形成输出光OUT1中的B3f。所述中间输出耦合元件DOE3g可以通过衍射波导光B1g形成输出光OUT1中的B3g。所述中间输出耦合元件DOE3h可以通过衍射波导光B1h形成输出光OUT1中的B3h。
通过选择输出耦合元件的光栅矢量，可以使得输出光中的光束B3a，B3b，B3c，B3d，B3e，B3f，B3g，B3h对于同一图像点相互平行。
参考图9d，输出耦合元件可以形成输出光束，使得每个输出光束的方向和强度可以对应于所显示图像VIMG1的同一图像点的位置和亮度。
例如，每个输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d、DOE3e、DOE3f、DOE3g、DOE3h可以形成一个输出光束，使得输出光束(B3aP0,R,B3bP0,R,B3cP0,R,B3dP0,R,B3eP0,R,B3fP0,R,B3gP0,R,B3hP0,R)在不同的输出耦合元件下相互平行，其中，输出光束对应于所显示图像VIMG1的同一图像点(P0)，下标"R"表示红色色光。
输出平行光束可以确保所显示的图像点(P0)在视觉上显示为单个点，并且还可以确保扩 展器设备EPE1的旋转不会导致所显示图像点(P0)出现视觉可检测的偏移。
参考图10a，输入耦合元件DOE1可以具有第一输入光栅矢量V1a和第二输入光栅矢量V1c。第一输入光栅矢量V1a的大小可由输入耦合元件DOE1的衍射光栅G1a的光栅周期d1a确定。第一输入光栅矢量V1a的方向可以由相对于参考方向的角度β1a指定。
例如，参考方向可以是第一输入光栅矢量V1a的方向，在这种情况下，方向角β1a等于零度(即β1a＝0°)。
参考方向也可以是例如SX方向，在图像扩展器EPE1静止情况下。图像扩展器EPE1可以在旋转或静止状态下，使得第一输入光栅矢量V1a平行于SX方向。
第二输入光栅矢量V1c的大小可由输入耦合元件DOE1的衍射光栅G1c的光栅周期d1c确定。第二输入光栅矢量V1c的方向可以由相对于参考方向的角度β1c指定。
衍射光栅G1a可包含衍射特征F1a。衍射光栅G1c可包含衍射特征F1c。衍射特征F1a、F1c可以是例如微观脊或凹槽(见图12a)。
输入耦合元件DOE1还可以包括由衍射特征F1的二维阵列构成的二维光栅G1(见图12b)。
在一实施例中，输入耦合元件DOE1可以具有两个不同的光栅周期d1a和d1c以优化与多色光的均匀性问题。第一光栅周期d1a可以允许显示图像的第一颜色分量(例如绿色G)。第二光栅周期d1c可以允许显示图像的第二颜色分量(例如红色R)。光栅矢量V1c的幅度可以不同于光栅矢量V1a，以利于彩色图像的显示。
在一实施例中，输入耦合元件DOE1的第一光栅周期d1a可以等于输入耦合元件DOE1的第二光栅周期d1c。输入耦合元件DOE1的第一输入光栅矢量V1a的幅度可以等于输入耦合元件DOE1的第二输入光栅矢量V1c的幅度。在该情况下，图像扩展器EPE1可以包括例如四个或更多个输出耦合元件DOE3a、DOE3b、DOE3c、DOE3d，以减少视觉上可检测到的闪烁和/或允许降低的图像扩展器EPE1的转速。
参考图10b，输入耦合元件DOE1还可以具有第三输入光栅矢量V1b和第四输入光栅矢量V1d。第三输入光栅矢量V1b的幅度大小可以等于第一输入光栅矢量V1a，并且第三输入光栅矢量V1b的方向可以与第一输入光栅矢量V1a相反。第四输入光栅矢量V1d的幅度可以等于第二输入光栅矢量V1c，并且第四输入光栅矢量V1d的方向可以与第二输入光栅矢量V1b相反。
参考图10c，光栅矢量V1a、V1c之间的角α1ac可以在例如60°至120°的范围内。特别地，角α1ac基本上等于90°。
参考图11a，输入耦合元件DOE1还可以向由输入耦合元件DOE1的光栅向量总和所指定的中间方向提供中间波导光。特别地，输入耦合元件DOE1可以提供第一中间波导光B1e到由矢量V1a+V1b所指定的方向；输入耦合元件DOE1可以提供第一中间波导光B1f到由矢量V1b+V1d所指定的方向；输入耦合元件DOE1可以提供第一中间波导光B1g到由矢量V1b+V1c所指定的方向；输入耦合元件DOE1可以提供第一中间波导光B1h到由矢量V1a+V1d所指定的方向。
第一输入光栅矢量V1a的幅度可以等于或不同于第一输入光栅矢量V1aV1c的大小。第一中间方向的方向角β1e也可以不等于45°。
参考图11b，对于同一图像点，可以选择输出耦合元件的衍射特征，使得由不同的输出耦合元件形成的输出光束相互平行。
主输出耦合元件DOE3a可能具有衍射光栅G3a，其包含衍射特征F3a，光栅周期d3a。输出耦合元件DOE3a的光栅矢量V3a的方向由方向角β3a指定。
主输出耦合元件DOE3b可能具有衍射光栅G3b，其包含衍射特征F3b，光栅周期d3b。输出耦合元件DOE3b的光栅矢量V3b的方向由方向角β3b指定。
主输出耦合元件DOE3c可能具有衍射光栅G3c，其包含衍射特征F3c，光栅周期d3c。输出耦合元件DOE3c的光栅矢量V3c的方向由方向角β3c指定。
主输出耦合元件DOE3d可能具有衍射光栅G3d，其包含衍射特征F3d，光栅周期d3d。输出耦合元件DOE3d的光栅矢量V3d的方向由方向角β3d指定。
中间输出耦合元件DOE3e可能具有衍射光栅G3e，其包含衍射特征F3e，光栅周期d3e。输出耦合元件DOE3e的光栅矢量V3e的方向由方向角β3e指定。
中间输出耦合元件DOE3f可能具有衍射光栅G3f，其包含衍射特征F3f，光栅周期d3f。输出耦合元件DOE3f的光栅矢量V3f的方向由方向角β3f指定。
中间输出耦合元件DOE3g可能具有衍射光栅G3g，其包含衍射特征F3g，光栅周期d3g。输出耦合元件DOE3g的光栅矢量V3g的方向由方向角β3g指定。
中间输出耦合元件DOE3h可能具有衍射光栅G3h，其包含衍射特征F3h，光栅周期d3h。输出耦合元件DOE3h的光栅矢量V3h的方向由方向角β3h指定。
输入耦合元件DOE1可以有四个光栅向量，它们满足以下条件：
V1a+V1b＝0      (1a)
V1c+V1d＝0      (1b)
其中，光栅矢量V1b与光栅矢量V1a幅度相等，方向相反；光栅矢量V1c与光栅矢量V1d幅度相等，方向相反。
例如，第一输入光栅矢量V1a和第二输入光栅矢量V1c之间的角度α1ac可以在60°至120°的范围内。特别地，角α1ac可以等于90°。因此，每个输出耦合元件可以选择性地衍射波导光，以提供最佳的图像质量。换句话说，可以减少或避免鬼像的形成。
输入耦合元件DOE1可以包括第一光栅区域G1a以提供光栅矢量V1a和V1b，同时该输入耦合元件DOE1也可以包括第二光栅区域G1a以提供光栅矢量V1c和V1d。或者，DOE1的输入耦合元件可以包括二维光栅以提供四个光栅矢量V1a、V1b、V1c、V1d。二维光栅可以包括例如微观衍射突起或凹陷的二维阵列。
图像扩展器可以包括四个主要的输出耦合元件，通过衍射将波导光从光波导板内耦合出来。图像扩展器可以包括四个主要的输出耦合元件，每个主输出耦合元件的光栅矢量均与输入耦合元件的相应光栅矢量相反。
可以选择主输出耦合元件(DOE3a，DOE3b，DOE3c，DOE3d)的光栅周期(d)和光栅向量的方向(β)，以满足以下条件，可使不同的输出耦合元件提供的输出光束对于同一图像点保持平行。
V1a+V3a＝0        (2a)
V1b+V3b＝0       (2b)
V1c+V3c＝0        (2c)
V1d+V3d＝0       (2d)
可以选择第一主输出耦合元件DOE3a的衍射特征F3a，使得第一输入光栅矢量V1a和第一输出光栅矢量V3a的和为零。
可以选择第二主输出耦合元件DOE3c的衍射特征F3c，使得第二输入光栅矢量V1c和第二输出光栅矢量V3c的和为零。
输入光栅矢量V1b和输出光栅矢量V3b的总可以为零。输入光栅矢量V1d和输出光栅矢量V3d的和可以为零。
图像扩展器还可以包括一个、两个、三个或四个中间输出耦合元件，通过衍射将波导光从光波导板中耦合出来。图像扩展器可以包括四个中间输出耦合元件，使得每个中间输出耦合元件的光栅矢量可以与相邻两个输入光栅矢量的矢量和之和为零。
可以选择中间输出耦合元件(DOE3e、DOE3f、DOE3g、DOE3h)的光栅周期(d)和光栅矢量的方向(β)，以满足以下条件，可使不同的中间输出耦合元件提供的输出光束对于同一图像点保持平行。
V1a+V1c+V3e＝0      (3a)
V1b+V1d+V3f＝0      (3b)
V1b+V1c+V3g＝0       (3c)
V1a+V1d+V3h＝0     (3d)
公式(1a)到(3d)指定波导内光栅矢量和的条件，其中公式(1a)到(3d)的每一项都是矢量，具 有大小和方向。
特别地，可以选择第一中间输出元件DOE3e的衍射特征F3e的位置，使得第一输入光栅向量V1a、第二输入光栅向量V1c和第一中间输出光栅向量V1e的总和等于零。
参考图12a，输入耦合元件DOE1可以包括第一光栅区域G1a，其具有光栅周期d1a和光栅矢量V1a。输入耦合元件DOE1可以包括第二光栅区域G1c，其具有光栅周期d1c和光栅矢量V1c。光栅区域G1a具有衍射特征F1a。光栅区域G1c具有衍射特征F1c。衍射特征F1a、F1c可以是例如微观脊或凹槽。第一光栅区域G1a可以例如在光波导板SUB1的第一主表面SRF1上设置，并且第二光栅区域G1c可以例如在光波导板SUB1的第二主表面SRF2上设置。当在光波导板SUB1的轴向方向(AX1，SZ)上观察时，第一光栅区域G1a可以部分或完全与第二光栅区域G1c重叠。
参考图12b，输入耦合元件DOE1可以包括二维光栅G1，其具有第一输入光栅矢量V1a和第二输入光栅矢量V1c。二维光栅G1可以具有第一光栅周期d1a和第二光栅周期d1c。二维光栅G1可能具有衍射特征F1的二维阵列。衍射特征F1可以是例如微观突起或凹陷。
参考图12c和12d，输入耦合元件DOE1可以包括两个或多个空间上独立的光栅区域G1a、G1b、G1c、G1d，使得内耦合元件DOE1可以具有光栅向量V1a、V1c。
每个形成的波导光只能通过一个输出耦合元件耦合出来。错误的输出耦合元件的衍射可能会导致形成视觉上令人不安的鬼影图像。可以通过选择光栅元件衍射特征的位置，使图像扩展器不会形成或减少、避免鬼影图像。
可以选择光栅元件衍射特征的位置，使得任何一对光栅矢量的方向彼此相等或足够差异，从而减少或避免形成鬼影图像。
可以选择光栅元件衍射特征的位置，使得各输出耦合元件的光栅矢量的幅度相等，从而减少或避免形成鬼影图像。
如果两个相邻的输出耦合元件(例如DOE1a和DOE1e)的光栅矢量的方向不同，则相邻的输出耦合元件的光栅矢量的夹角可以例如大于30°，以减少或避免形成鬼影图像。
一般而言，光引擎ENG1也可以与显示装置500分开设置。光引擎ENG1可以是显示装置500的可替换部分。显示装置500也可以在没有光引擎ENG1的情况下交付。显示装置500可以包括图像扩展器EPE1和旋转装置，也无需光引擎ENG1。光引擎ENG1可以安装在显示装置500上，例如在服务站点或由用户USER1自行安装。在一实施例中，第一光引擎ENG1可以被第二光引擎取代。车载抬头显示装置500也可以在没有光引擎ENG1的情况下交付。
在一实施例中，图像扩展器EPE1的光波导板SUB1可以是透明的，使得外部光EX1可以沿轴向(AX1，SZ)透过光波导板SUB1。例如，用户USER1在观看所显示的虚拟图像VIMG1时，可以透过光波导板SUB1同时观察到外部物体OBJ1。外部光EX1可以从外部物体OBJ1通过光波导板SUB1传播到用户USER1的眼睛EYE1。
在一实施例中，光波导板SUB1可以包括切口或开口，以便外部光EX1可以通过切口或开口在轴向(AX1，SZ)传播。外部光EX1可通过切口或开口从外部对象OBJ1传播到用户USER1的眼睛EYE1。
本发明实施例还提供了一种车用抬头显示设备，包括如上所述的大区域显示装置。
参考图3a至3c，显示装置500可以是车载抬头显示器，其中车辆1000可以设置显示装置500。车辆可以是电动汽车、内燃汽车、摩托车、有轨电车、火车、船只、飞机等交通工具。
在驾驶车辆时，驾驶员USER1可能需要观察与驾驶相关的信息，例如，车辆的显示装置500可以设置为显示关于车辆速度、电池状态、车辆电机状态和/或导航指令等信息。显示装置500的用户USER1可以是车辆的驾驶员或乘客。除了显示的虚拟图像VIMG1之外，用户USER1还可以通过显示区域DAR1看到真实物体OBJ1和/或环境。当使用显示装置500时，驾驶员USER1不需要为了观察车辆信息而低头查看仪表盘，可以通过车辆的挡风玻璃同时观 察到外界环境和车辆信息，避免低头的需要以提高驾驶安全性。驾驶员的视线LIN1可以与显示装置500的有效显示区域DAR1相交。
旋转图像扩展器EPE1可以通过使用更小的输出耦合元件来提供更大的显示区域DAR1。这可以为用户USER1提供大的Eye Box(BOX1)。只要用户的眼睛EYE1保持在显示装置500的Eye Box范围内，就可以观察到完整虚拟图像VIMG1。旋转图像扩展器EPE1可以为输出光OUT1提供均匀的空间强度分布，并提供更高的图像显示质量。与大的输出耦合元件相比，较小的输出耦合元件会更容易生产，成本更低。
更大的显示区域DAR1也可以便于显示具有大角宽和/或大角高Δθ的虚拟图像VIMG1。由于显示区域DAR1增大，眼睛EYE1与图像扩展器EPE1之间的距离较大时，用户也可以看到完整的虚拟图像VIMG1，或至少大部分虚像VIMG1。
显示装置500可以经由基座BASE1安装到车辆1000。例如，底座BASE1可以安装到窗户WIN1、仪表盘或车辆1000天花板上。
用户USER1的眼睛EYE1可以从外部物体OBJ1接收外部光EX1。当外部光线EX1照射在眼睛EYE1上时，用户USER1可以观察外部物体OBJ1。外部光EX1可以通过窗口WIN1并通过显示装置500的显示区域DAR1传播到用户USER1的眼睛EYE1。用户USER1可以同时观察外部物体OBJ1和显示的虚拟图像VIMG1。
参考图3c，窗口WIN1也可作为显示装置500的一部分来操作，其中窗口WIN1可以是例如车辆1000的挡风玻璃。窗口WIN1可以将输出光OUT1反射向用户EYE1，使得用户可以通过窗口WIN1看到显示的虚拟图像VIMG1。其中用户EYE1可以通过窗口WIN1同时观察车辆1000的外部环境，例如，从外部物体OBJ1到眼睛EYE1的视线LIN1可以与显示区域DAR1相交。例如，用户可以通过窗口WIN1观察外部对象OBJ1，使得显示的虚拟图像VIMG1可以在视觉上与外部对象OBJ1重叠。
窗口WIN1可以是平面(平坦)透明窗口或弯曲透明窗口。平面窗口可以反射输出光OUT1而不使显示的虚拟图像VIMG1变形。弯曲的窗口可能会使显示的虚拟图像VIMG1变形，此时显示装置500应设置为可至少部分地补偿虚拟图像VIMG1的变形。
窗口WIN1可以同时透射外部光EX1并反射输出光OUT1到用户USER1的眼睛EYE1。窗口WIN1可以采用半透半反玻璃，使其可以同时透射外部光EX1并反射输出光OUT1。
在一实施例中，窗口WIN1可以涂覆有半透半反涂层，以增加反射输出光的强度。涂层可以是例如介电或金属涂层。
在一实施例中，半透半反窗口WIN1也可以基于由窗的折射率和空气的折射率之间的差异引起的菲涅耳反射来操作，此时的窗口WIN1不需要涂覆反射涂层。
本发明实施例还提供了一种虚拟图像显示方法，采用如上所述的大区域显示装置实现。
由于方法部分的实施例与装置部分的实施例相互对应，因此方法部分的实施例请参见装置部分的实施例的描述，这里暂不赘述。
说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。对于实施例公开的系统而言，由于其与实施例公开的方法相对应，所以描述的比较简单，相关之处参见方法部分说明即可。应当指出，对于本技术领域的普通技术人员来说，在不脱离本申请原理的前提下，还可以对本申请进行若干改进和修饰，这些改进和修饰也落入本申请权利要求的保护范围内。
还需要说明的是，在本说明书中，诸如第一和第二等之类的关系术语仅仅用来将一个实体或者操作与另一个实体或操作区分开来，而不一定要求或者暗示这些实体或操作之间存在任何这种实际的关系或者顺序。而且，术语“包括”、“包含”或者其任何其他变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。

Claims (11)

  1. 一种大区域显示装置，其特征在于，包括用于产生输入图像并将输入图像转化为输入光的光引擎、对所述输入光进行扩展的图像扩展器以及用于旋转所述图像扩展器以产生大区域显示的驱动装置；
    所述图像扩展器包括光波导板，所述光波导板上设置有用于将输入光耦合至所述光波导板上并在光栅方向形成至少一个波导光的输入耦合元件和用于将波导光耦合输出的第一主输出耦合元件和第二主输出耦合元件；
    所述输入耦合元件具有第一输入光栅矢量和第二输入光栅矢量；所述第一主输出耦合元件具有第一输出光栅矢量，所述第二主输出耦合元件具有第二主输出光栅矢量；其中，所述第一输入光栅矢量和第一输出光栅矢量的矢量和为零，第二输入光栅矢量和第二输出光栅矢量的矢量和为零，所述输入耦合元件的第一输入光栅矢量和第二输入光栅矢量之间的角度为60°～120°。
  2. 根据权利要求1所述的大区域显示装置，其特征在于，且第一输入光栅矢量的大小不同于和第二输入光栅矢量的大小。
  3. 根据权利要求1所述的大区域显示装置，其特征在于，所述输入耦合元件还具有第三输入光栅矢量；所述第三输入光栅矢量与第一输入光栅矢量大小相等，方向相反；
    所述光波导板上还设置有第三主输出耦合元件，所述第三主输出耦合元件具有第三输出光栅矢量，所述第三输入光栅矢量和第三输出光栅矢量的矢量和为零；所述输入耦合元件位于第一主输出耦合元件和第三主输出耦合元件之间。
  4. 根据权利要求3所述的大区域显示装置，其特征在于，所述输入耦合元件还具有第四输入光栅矢量；所述第四输入光栅矢量与第二输入光栅矢量大小相等，方向相反；
    所述光波导板上还设置有第四主输出耦合元件，所述第四主输出耦合元件具有第四输出光栅矢量，所述第四输入光栅矢量和第四输出光栅矢量的矢量和为零；所述输入耦合元件位于第二主输出耦合元件和第四主输出耦合元件之间。
  5. 根据权利要求1所述的大区域显示装置，其特征在于，所述输入耦合元件形成的波导光包括中间波导光；
    所述光波导板还设置有至少一个用于将中间波导光耦合输出的中间输出元件，所述中间输出元件位于第一主输出耦合元件和第二主输出耦合元件之间，所述中间输出元件具有中间输出光栅矢量，并使得第一输入光栅矢量、第二输入光栅矢量和中间输出光栅矢量的矢量和为零。
  6. 根据权利要求1所述的大区域显示装置，其特征在于，所述驱动装置以固定转速旋转所述图像扩展器，所述固定转速为每秒5至200转；
    所述驱动装置带动图像扩展器围绕一旋转轴且相对于一固定基座旋转和/或振动，其中，所述输入耦合元件与所述旋转轴的间隔小于所述光波导板直径的5％；
    所述光引擎通过一保护盖与所述固定基座机械连接，所述保护盖为透明或半透明保护盖。
  7. 根据权利要求1所述的大区域显示装置，其特征在于，所述光引擎用于产生输入图像，并将所述输入图像转换为输入光中的多个子输入光束；
    所述图像扩展器将输入光中的多个子输入光束扩束，并形成输出光中的多个子输出光束。
  8. 根据权利要求1所述的大区域显示装置，其特征在于，所述输入耦合元件包括一个二维衍射光栅，所述二维衍射光栅均具有对应的光栅周期和光栅矢量，且光栅矢量的大小与光栅周期成反比。
  9. 根据权利要求1所述的大区域显示装置，其特征在于，所述输入耦合元件包括两个或多个具有不同衍射性能的光栅区域；
    所述输入耦合元件包括两个一维衍射光栅，以在第一方向和第二方向产生衍射，且所述 第一方向与第二方向正交；
    所述一维衍射光栅或者二维衍射光栅均具有对应的光栅周期和光栅矢量，且光栅矢量的大小与光栅周期成反比。
  10. 一种车用抬头显示设备，其特征在于，包括如权利要求1～9任一项所述的大区域显示装置。
  11. 一种虚拟图像显示方法，其特征在于，采用如权利要求1～9任一项所述的大区域显示装置实现。
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