Device for realizing near-eye display of three-dimensional images

Abstract

The present invention relates to display technology, and in particular to a device for realizing near-eye display of three-dimensional images. According to one aspect of the present invention, the device for realizing near-eye display of three-dimensional images comprises: a light field reproduction unit, which is configured to reconstruct light field information of a target object to reproduce a virtual scene, and the light field reproduction unit comprises: a spatial light modulator; and a phase plate arranged in the light output direction of the spatial light modulator, which has a diffraction structure, and the diffraction structure is configured to project images of different perspectives in the virtual scene to their respective corresponding observation positions; and a virtual-real fusion unit, which is configured to output a three-dimensional image that fuses the virtual scene with the real scene.

Description

Technical Field

[0001] The present invention relates to display technology, and in particular to a device for realizing near-eye display of three-dimensional images. Background Art

[0002] Current three-dimensional displays are mainly based on the binocular parallax principle of the human eye, which uses optical elements such as parallax barriers or cylindrical lens arrays to enable the left and right eyes of a person to obtain different image information.

[0003] In the near-eye display devices disclosed in US Patents US8989535B2 and US9581820B2, a micro-projection device is combined with an optical waveguide lens to realize an augmented reality 3D display based on binocular parallax, but this method is difficult to eliminate the axis convergence contradiction and is prone to visual fatigue. US Patent US00795952 discloses a method of realizing light field three-dimensional display by combining optical fiber micro-projection and optical waveguide lenses, but this method is technically difficult. US Patent US008014050B2 discloses an optical holographic phase plate for three-dimensional display. The described nanophase plate includes a volume grating structure and a photosensitive material. The diffraction efficiency and phase delay of a single pixel unit can be controlled through a single electrode array to realize rapid regulation of the light field phase. However, it is difficult to miniaturize and modulate a single pixel using this electrode array, and its display effect is difficult to meet the comfort and clarity required by consumers. Summary of the invention

[0004] An object of the present invention is to provide a device for realizing near-eye display of three-dimensional images, which has the advantages of low manufacturing cost, simple design and compact structure.

[0005] According to one aspect of the present invention, a device for realizing near-eye display of a three-dimensional image comprises:

[0006] A light field reproduction unit is configured to reconstruct light field information of a target object to reproduce a virtual scene, the light field reproduction unit comprising:

[0007] a spatial light modulator; and

[0008] A phase plate arranged in the light emitting direction of the spatial light modulator has a diffraction structure, and the diffraction structure is configured to project images of different viewing angles in the virtual scene to respective corresponding observation positions; and

[0009] The virtual-reality fusion unit is configured to output a three-dimensional image that fuses the virtual scene with the real scene.

[0010] Preferably, in the above device, the device further comprises a projection unit, which is configured to transmit the virtual scene output by the light field reproduction unit to the virtual-reality fusion unit.

[0011] Preferably, in the above device, the spatial light modulator includes a plurality of body pixels, each body pixel includes a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, and the diffraction structure includes a plurality of nanostructure units, each nanostructure unit is configured to project a light beam from a sub-pixel corresponding to the same viewing angle in the plurality of body pixels to the same observation position associated with the sub-pixel.

[0012] Preferably, in the above device, the spatial light modulator includes a plurality of body pixels, each body pixel includes a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, and the diffraction structure includes a plurality of nanostructure units, each nanostructure unit is configured to project a light beam from a sub-pixel corresponding to the same viewing angle in the plurality of body pixels to a set of observation positions associated with the sub-pixel.

[0013] Preferably, in the above device, a group of observation positions is a plurality of observation positions distributed along the horizontal direction and / or the lateral direction.

[0014] Preferably, in the above device, the spatial light modulator is one of the following: a DLP display screen, an LCOS display screen or a liquid crystal display screen.

[0015] Preferably, in the above device, the virtual-real fusion unit includes a waveguide, a first nanograting and a second nanograting arranged inside the waveguide, wherein the first nanograting diffracts the incoming light, the waveguide totally reflects the light diffracted by the first nanograting, and the second nanograting diffracts the totally reflected light to guide the light from the waveguide to the visible area.

[0016] Preferably, in the above device, the virtual-reality fusion unit comprises three layers of transparent light field lenses stacked together, each layer of the transparent light field lenses comprises a waveguide, a first nanograting and a second nanograting arranged inside the waveguide, wherein the first nanograting diffracts the incoming light, the waveguide totally reflects the light diffracted by the first nanograting, and the second nanograting diffracts the totally reflected light to guide the light from the waveguide to the visible area, wherein the first nanograting of each layer of the transparent light field lenses has different orientation angles and / or periods, and the second nanograting of each layer of the transparent light field lenses has different orientation angles and / or periods.

[0017] Preferably, in the above device, the virtual-real fusion unit comprises a prism, a waveguide and a nano-grating arranged inside the waveguide, wherein the prism refracts the incident light into the waveguide, the waveguide totally reflects the refracted light, and the nano-grating diffracts the totally reflected light to guide the light from the waveguide to the visible area.

[0018] Preferably, in the above-mentioned device, the virtual-real fusion unit includes a prism, a waveguide and a pair of reflectors arranged inside the waveguide, wherein the prism refracts the incident light into the waveguide, the waveguide totally reflects the refracted light, and the reflector diffracts the totally reflected light to guide the light from the waveguide to the visible area.

[0019] Preferably, in the above device, the virtual-real fusion unit comprises a first waveguide lens, a second waveguide lens, a first group of nanogratings, a second group of nanogratings and a third group of nanogratings, the first group of nanogratings is located between the first and second waveguide lenses, the second group of nanogratings is located on the surface of the second waveguide lens away from the first waveguide lens, the third group of nanogratings is located on the second group of nanogratings, and the first to third groups of nanogratings have different orientation angles and / or periods. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic block diagram of a device for implementing near-eye display of three-dimensional images according to an embodiment of the present invention.

[0021] Figure 2 For use in Figure 1 Schematic diagram of the structure of the phase plate in the device shown.

[0022] Figure 3 for Figure 2 Schematic diagram of the structure of the phase plate in the XY plane and the XZ plane.

[0023] Figure 4 Nanostructure distribution diagram of directional functional film to achieve single viewpoint convergence.

[0024] Figure 5a and 5b They are schematic diagrams of realizing single viewpoint and multi-viewpoint by using a light field reconstruction unit according to another embodiment of the present invention.

[0025] Figure 6 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0026] Figure 7 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0027] Figure 8 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0028] Fig. 9 FIG. 4 is a top view of a virtual-reality fusion unit according to another embodiment of the present invention.

[0029] Fig.10 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0030] Fig.11a and 11b Schematic diagram of using the phase plate as described above to achieve longitudinal and lateral expansion of the visible area respectively. Fig.12 Schematic diagram of a virtual-real fusion unit according to another embodiment of the present invention.

[0031] Fig.13 It is a schematic diagram of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0032] Fig.14 It is a schematic diagram of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention. DETAILED DESCRIPTION

[0033] The purpose of the present invention will be described in detail below with reference to the accompanying drawings.

[0034] Figure 1 The present invention is a schematic block diagram of a device for implementing near-eye display of three-dimensional images according to an embodiment of the present invention.

[0035] Figure 1 The device 100 for implementing near-eye display of three-dimensional images includes a light field reproduction unit 110, a projection unit 120, and a virtual-real fusion unit 130. In this embodiment, the light field reproduction unit 110 is configured to reconstruct the light field information of the target object to reproduce the virtual scene. The projection unit 120 is optically coupled between the light field reproduction unit 110 and the virtual-real fusion unit 130, and is configured to transmit the virtual scene output by the light field reproduction unit 110 to the virtual-real fusion unit 130, for example, by a geometric optical method such as reflection, refraction, or diffraction. The virtual-real fusion unit 130 is configured to output a three-dimensional image that fuses the virtual scene with the real scene.

[0036] It should be noted that the projection unit 120 is an optional component. Optionally, through appropriate design, the virtual scene reconstructed by the light field reproduction unit 110 can be directly coupled to the virtual-reality fusion unit 130 .

[0037] In this embodiment, the light field reconstruction unit 110 includes a spatial light modulator and a phase plate to achieve light field reconstruction.

[0038] The spatial light modulator is used for amplitude modulation, that is, loading multi-view mixed image information. The spatial light modulator may include, for example, a display panel, a driving circuit, a control system, and software control. According to the needs of the specific application field, the spatial light modulator can realize monochrome or color display. Preferably, the spatial light modulator can adopt one of a DLP display screen, an LCOS display screen, and a liquid crystal display screen. The spatial light modulator may include a plurality of body pixels or amplitude modulated pixels, each body pixel includes a plurality of sub-pixels, and each sub-pixel corresponds to a different viewing angle.

[0039] The phase plate has a diffraction grating structure, which includes a plurality of hoxels. Further, each hoxel of the phase plate includes a plurality of nanostructure units, each of which is matched and aligned with a viewing angle image pixel of the spatial light modulator, that is, a light beam corresponding to a sub-pixel of the same viewing angle from the plurality of hoxels of the spatial light modulator is projected to a set of observation positions associated with the sub-pixel.

[0040] Figure 2 For use in Figure 1 Schematic diagram of the structure of the phase plate in the device shown.

[0041] Without loss of generality, Figure 2 The illustrated case is based on 5 viewing angles and only shows three pixels of the phase plate, but it is obvious that the present embodiment can be applied to cases with other viewing angles. Figure 2 As shown, the phase plate 212 includes body pixels 212A-212C. Each body pixel of the phase plate 212 is in the form of a pixel unit and includes 5 nano-grating regions or sub-pixels with different periods and / or orientation angles. When the light from the sub-pixel of the spatial light modulator arrives, different nano-grating regions will deflect the light to different observation positions or viewing angles 1-5, thereby realizing the projection of the light beam of the same viewing angle to multiple observation positions, thereby realizing three-dimensional display with separated viewing angles. Similarly, through the design of the phase plate, multiple separated or continuous viewpoints distributed in dot arrays, line arrays, and surface arrays can be realized to achieve the effect of the best observation area.

[0042] The period and orientation angle of the grating region can be determined according to the following grating equation:

[0043] tanφ 1 =sinφ / (cosφ-nsinθ(Λ / λ)) (1)

[0044] sin 2 (θ 1 )=(λ / Λ) 2 +(nsinθ) 2 -2nsinθcosφ(λ / Λ) (2)

[0045] Among them, θ 1 and φ 1 They respectively represent the diffraction angle (the angle between the diffracted light and the negative direction of the Z axis) and the azimuth (the angle between the diffracted light and the positive direction of the Y axis) of the diffracted light, θ and λ respectively represent the incident angle (the angle between the incident light and the negative direction of the Z axis) and the wavelength of the light source, Λ and φ respectively represent the period and orientation angle (the angle between the groove direction and the positive direction of the X axis) of the nano-diffraction grating, and n represents the refractive index of the light wave in the medium.

[0046] Figure 3 for Figure 2 Schematic diagram of the structure of the phase plate in the XY plane and the XZ plane.

[0047] Once the wavelength of the incident light, the incident angle, the diffraction angle of the diffracted light, and the diffraction azimuth are determined, the above formula can be used to calculate the required grating period and orientation angle. The period and orientation angle of the nanostructure unit determine the modulation characteristics of the light field angle and spectrum. By designing the change pattern of the orientation angle and period of the nanostructure unit, the light field can be regulated and converted. The diffraction grating structure shown can be directly manufactured as a functional thin film layer on, for example, a glass substrate.

[0048] As mentioned above, each nano-grating area is regarded as a pixel unit or sub-pixel. The orientation of the grating area determines the angle modulation characteristics of the light field, and its period determines the spectral filtering characteristics. By continuously changing the period (spatial frequency) and orientation of each nano-grating area between each sub-pixel, the regulation and transformation of the light field can be achieved. Therefore, after making multiple grating areas with different orientation angles and periods set as required on a screen surface, enough viewpoints can be obtained, and with the help of amplitude control, 3D display under multi-viewing angles can be achieved.

[0049] Figure 4 The nanostructure distribution diagram of the directional functional film for achieving single viewpoint convergence. The nanostructure shown has a single off-axis Fresnel structure that can converge the image at viewpoint 1. Figure 4 In the structure shown, n×m sub-pixels form n×m off-axis Fresnel structures with different focal points. It should be noted that Figure 4 The shape of the sub-pixels in is not limited to a rectangle, and may also be a circle, a hexagon, or other shapes.

[0050] Figure 5a and 5b They are schematic diagrams of realizing single viewpoint and multi-viewpoint by using a light field reconstruction unit according to another embodiment of the present invention.

[0051] Figure 5a and 5bThe light field reconstruction unit 510 shown in the figure includes a spatial light modulator (eg, a liquid crystal display screen) 511 and a phase plate 512 (eg, a phase plate having grating regions with different orientations and / or periods) disposed on its surface. Figure 2 The phase plate structure shown in FIG. 5 ) is a phase plate 512 that focuses the light passing through the spatial light modulator 511 to one or more viewpoints.

[0052] Figure 6 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0053] Figure 6 The device 600 shown includes a light field reconstruction unit 610 , a projection unit 620 , and a virtual-real fusion unit 630 .

[0054] The light field reproduction unit 610 includes a liquid crystal display screen 611 and a phase plate 612 located on the light emitting surface of the liquid crystal display screen. Figure 2 The light field information of the object reproduced by the light field reproduction unit 610 is coupled to the virtual-real fusion unit 630 through, for example, diffraction, refraction or reflection of the projection unit 620 .

[0055] In this embodiment, the virtual-real fusion unit 630 includes a waveguide 631, a first nano-grating 632a and a second nano-grating 632b. Figure 6 The first nano-grating 632a is disposed inside the waveguide 631 and close to the position where the light enters the waveguide, and diffracts the light entering. The light diffracted by the first nano-grating 632a is totally reflected inside the waveguide 631. After multiple total reflections, the light reaches the second nano-grating 632b, and then is diffracted by the second nano-grating 632b and emitted to the visible area outside the waveguide, thereby outputting a three-dimensional image that merges the virtual scene with the real scene.

[0056] Figure 7 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0057] Figure 7 The device 700 shown includes a light field reconstruction unit 710 , a projection unit 720 and a virtual-real fusion unit 730 .

[0058] The light field reproduction unit 710 includes a liquid crystal display screen 711 and a phase plate 712 located on the light emitting surface of the liquid crystal display screen. Figure 2 The light field information of the object reproduced by the light field reproduction unit 710 is coupled to the virtual-real fusion unit 730 through, for example, diffraction, refraction or reflection of the projection unit 720 .

[0059] This embodiment and Figure 6 The main difference of the embodiment shown is the structure of the virtual-real fusion unit. Specifically, the virtual-real fusion unit 730 of this embodiment includes a prism 731, a waveguide 732, and a nano-grating 733 located inside the waveguide. Figure 7 The projection unit 720 projects the virtual scene from the light field reproduction unit 710 onto the prism 731, and the virtual scene enters the waveguide 732 after being refracted by the prism 731. The refracted light is totally reflected inside the waveguide 732. After multiple total reflections, the light reaches the nano grating 733, and then is diffracted by the nano grating 733 and emitted to the visible area outside the waveguide, thereby outputting a three-dimensional image that fuses the virtual scene with the real scene.

[0060] Figure 8 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0061] Figure 8 The device 800 shown includes a light field reconstruction unit 810 , a projection unit 820 and a virtual-real fusion unit 830 .

[0062] The light field reproduction unit 810 includes a liquid crystal display screen 811 and a phase plate 812 located on the light emitting surface of the liquid crystal display screen. Figure 2 The light field information of the object reproduced by the light field reproduction unit 810 is coupled to the virtual-real fusion unit 830 through, for example, diffraction, refraction or reflection of the projection unit 820 .

[0063] This embodiment and Figure 6 The main difference of the embodiment shown is the structure of the virtual-real fusion unit. Specifically, the virtual-real fusion unit 830 of this embodiment includes a prism 831, a waveguide 832, and a pair of reflectors 833a and 833b located inside the waveguide. Figure 8 , the projection unit 820 projects the virtual scene from the light field reproduction unit 810 onto the prism 831, and the virtual scene enters the waveguide 832 after being refracted by the prism 831. The refracted light is totally reflected inside the waveguide 832. After multiple total reflections, the light reaches the reflector 833a, a part of which is reflected by the reflector 833a and guided to the visible area outside the waveguide, and the rest of the light passes through the reflector 833a to the reflector 833b and is reflected by the reflector 833b and guided to the visible area outside the waveguide, thereby outputting a three-dimensional image that fuses the virtual scene with the real scene.

[0064] Fig. 9 FIG. 4 is a top view of a virtual-real fusion unit according to another embodiment of the present invention.

[0065] Fig. 9The virtual-real fusion unit 930 shown is in the form of a diffractive optical element, and the surface of the element includes a plurality of functional areas 931-933, each of which contains a pixel-type nano-diffraction grating. In this embodiment, the nano-diffraction grating can be prepared using photolithography, nano-imprinting or holographic interference technology. Fig. 9 As shown, the first functional area 931 with a circular grating is used for light coupling input. It should be pointed out that the shape of the first functional area is not limited to a circle. After being coupled by the first functional area 931, the light is introduced into the second functional area 932 of the wedge-shaped diffraction grating, and the latter realizes the expansion of the image projected on the virtual-real fusion unit 930 in the X-axis direction. After the image is expanded in the X-axis direction by the second functional area 932, it is introduced into the third functional area 933. The functional area 933 realizes the expansion of the projected image in the Y-axis direction. As a result, the human eye can observe the virtual image with an enlarged viewing angle through the virtual-real fusion unit 930.

[0066] Fig.10 The figure is a schematic diagram of the structure of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0067] Fig.10 The device 1100 shown includes a light field reconstruction unit 1010 , a projection unit 1020 , and a virtual-real fusion unit 1030 .

[0068] The light field reproduction unit 1010 includes a liquid crystal display screen 1011 and a phase plate 1012 located on the light emitting surface of the liquid crystal display screen. Figure 2 The light field information of the object reproduced by the light field reproduction unit 1010 is coupled to the virtual-real fusion unit 1030, for example, through diffraction, refraction or reflection of the projection unit 1020. The virtual-real coupling unit 1030 includes a plurality of functional areas 1031-1033, which are connected to the virtual-real fusion unit 1030. Fig. 9 The functional areas 931-933 shown are similar and will not be described again here.

[0069] Fig.11a and 11b Schematic diagram of using the phase plate as described above to achieve longitudinal and lateral visual area expansion. Without loss of generality, only four viewing angles are taken as an example.

[0070] See also Fig.11a, which shows a body pixel of the phase plate 1112 (a rectangle divided into four regions in the figure), and the body pixel includes four sub-pixels (identified by numbers 1-4). Each sub-pixel corresponds to a sub-pixel of the spatial light modulator, which includes three stacked or arranged nano-grating pixel units. The nano-grating pixel units in the sub-pixel have different orientations and / or periods, so for each viewpoint, multiple windows 1a-1c with the same viewing angle information that are arranged vertically and continuously in the vertical direction can be formed, thereby achieving the effect of expanding the vertical field of view.

[0071] See also Fig.11b , similarly, it shows a plurality of hoxels of the phase plate 1112 (divided into four rectangles in the figure). Taking the hoxel on the far left as an example, the hoxel includes four sub-pixels (identified by numbers 1-4). Each sub-pixel corresponds to a sub-pixel of the spatial light modulator, which includes three stacked or arranged nano-grating pixel units. The nano-grating pixel units in the sub-pixel have different orientations and / or periods, so for each viewpoint, multiple horizontally continuously arranged windows with the same viewing angle information can be formed along the horizontal direction, thereby achieving the effect of expanding the horizontal field of view.

[0072] In the above example, extended viewing angle information is formed in the vertical or horizontal direction of the same viewpoint, and this viewing angle information is the same as the light field information covered by the original viewpoint, so the field of view angle can be increased without reducing the image resolution.

[0073] Preferably, in order to enable the human eye to observe virtual images at a wide field of view, the pixel structure of the phase plate can also use spatial multiplexing stacking or binary optical elements to display three-dimensional images with a wide viewing angle. The image reproduction information after the viewing angle is expanded is coupled into the virtual-real fusion unit through the projection unit. In practical applications, by matching the exit pupil of the projection optical unit and the entrance pupil of the virtual-real fusion lens, the observer can observe the three-dimensional scene with an expanded field of view through the virtual-real fusion unit without moving.

[0074] Fig.12 Schematic diagram of a virtual-real fusion unit according to another embodiment of the present invention.

[0075] Fig.12 The virtual-real fusion unit 1230 shown includes three subunits 1231-1233 stacked together, each of which can be Figure 6 The structure of the virtual-real fusion unit shown. For each subunit, by making the nano-grating therein have different orientation angles and / or periods, different images can be generated at different distances from the virtual-real fusion unit, thereby obtaining an image with a sense of depth of field.

[0076] Fig.13It is a schematic diagram of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0077] Fig.13 The near-eye display device 1300 shown in FIG. 1 can realize color display. To this end, in the device 1300, as shown in FIG. Fig.13 As shown, the light field reconstruction unit 1310 includes a spatial light modulator, a phase plate, and a filter located between the spatial light modulator and the phase plate. Without loss of generality, taking each somatic pixel of the phase plate (a rectangle divided into four regions in the figure) as an example, which includes four sub-pixels of different orientations (marked by numbers 1-4 in the figure), each sub-pixel corresponds to one of the four viewing angles. In this embodiment, the sub-pixels of the spatial light modulator match the pixels of the filter and the sub-pixels of the phase plate. Furthermore, each sub-pixel of the phase plate is composed of three sub-pixels or pixel grating units of R, G, and B (shown by different hatching lines in the figure). For each sub-pixel, by designing each pixel grating unit to have an appropriate orientation angle and period, the light rays passing through the three sub-pixels of R, G, and B can converge at the same viewpoint. The convergent viewpoint contains the color information of the image. The image is reconstructed by the light field reconstruction unit 1310, coupled to the virtual-real fusion unit 1330 through the projection unit 1320, and finally presents a colorful virtual image through the virtual-real fusion unit 1330. In actual three-dimensional display, the input of the spatial light modulator can be controlled by a computer to achieve video playback of color images.

[0078] Fig.14 It is a schematic diagram of a device for realizing near-eye display of three-dimensional images according to another embodiment of the present invention.

[0079] Fig.14 The near-eye display device 1400 shown can realize color display. Fig.14 In the device 1400 shown, the virtual-real fusion unit 1430 adopts a double-layer waveguide lens structure. Specifically, the virtual-real fusion unit 1430 includes a first waveguide lens 1431, a second waveguide lens 1432, a first group of nano gratings 1433a, 1433b, a second group of nano gratings 1434a, 1434b, and a third group of nano gratings 1435a, 1435b. Fig.14 The first group of nano-gratings 1433a and 1433b are located between the first and second waveguide lenses, the second group of nano-gratings 1434a and 1434b are located on the surface of the second waveguide lens 1432 away from the first waveguide lens 1431, and the third group of nano-gratings 1435a and 1435b are located on the second group of nano-gratings 1434a and 1434b.

[0080] In this embodiment, each group of nano gratings only diffracts light of a specific color (e.g., R, G, and B). The projection unit 1420 couples the light from the light field reproduction unit 1410 into the first waveguide lens 1431. Due to the wavelength selectivity of the grating, the light of a specific color (e.g., green) is totally reflected in the first waveguide lens 1431, while the light of other colors (e.g., blue and red) cannot be transmitted in the first waveguide lens 1431 because the diffraction angle does not meet the total reflection condition. Similarly, the second group of nano gratings 1434a, 1434b and the third group of nano gratings 1435a, 1435b, which have diffraction effects only on blue and red light, respectively, cause the blue and red light to be totally reflected in the second waveguide lens 1432. Thus, image information with different colors is transmitted through the waveguide lens without generating crosstalk. The virtual-real fusion unit 1430 projects a color convergent light field in front of the human eye.

[0081] Compared with the prior art, the device for realizing near-eye display of three-dimensional images of the present invention has many advantages. For example, the near-eye display device based on the microlens array of the present invention can automatically generate three-dimensional images, is simple to operate, has a compact structure, can work under incoherent light sources without special illumination light, and provides continuous parallax and observation points to the observer.

[0082] The above describes the principles and preferred embodiments of the present invention. However, the present invention should not be construed as being limited to the specific embodiments discussed. The preferred embodiments described above should be considered illustrative rather than restrictive, and it should be understood that those skilled in the art may make changes in these embodiments without departing from the scope of the present invention as defined in the following claims.

Claims

1. A device for realizing near-eye display of three-dimensional images, characterized in that: Include: A light field reproduction unit is configured to reconstruct light field information of a target object to reproduce a virtual scene, the light field reproduction unit comprising: a spatial light modulator; and A phase plate arranged in the light emitting direction of the spatial light modulator has a diffraction structure, and the diffraction structure is configured to project images of different viewing angles in the virtual scene to respective corresponding observation positions; and a virtual-real fusion unit, configured to output a three-dimensional image that fuses the virtual scene with the real scene, Each of the pixels of the spatial light modulator includes a plurality of sub-pixels corresponding to different viewing angles. Each body pixel of the phase plate includes a sub-pixel corresponding to the sub-pixel of the spatial light modulator, and each sub-pixel of the phase plate includes a nano-grating pixel unit with different orientations and / or periods, thereby forming a plurality of windows with the same viewing angle information that are continuously arranged in the vertical or horizontal direction for each viewpoint.

2. The device according to claim 1, wherein: The device further includes a projection unit configured to transmit the virtual scene output by the light field reproduction unit to the virtual-reality fusion unit.

3. The device according to claim 1, wherein: The spatial light modulator includes a plurality of body pixels, each body pixel includes a plurality of sub-pixels, each sub-pixel corresponds to a different viewing angle, and the diffraction structure includes a plurality of nanostructure units, each nanostructure unit is configured to project a light beam from a sub-pixel corresponding to the same viewing angle in the plurality of body pixels to the same observation position associated with the sub-pixel.

4. The device according to claim 1, wherein: The spatial light modulator is one of the following: a DLP display screen, an LCOS display screen or a liquid crystal display screen.

5. The device according to claim 1, wherein: The virtual-real fusion unit includes a waveguide, a first nanograting and a second nanograting arranged inside the waveguide, wherein the first nanograting diffracts the incoming light, the waveguide totally reflects the light diffracted by the first nanograting, and the second nanograting diffracts the totally reflected light to guide the light from the waveguide to the visible area.

6. The device as claimed in claim 1, wherein: The virtual-reality fusion unit comprises three layers of transparent light field lenses stacked together, each layer of the transparent light field lenses comprises a waveguide, a first nanograting and a second nanograting arranged inside the waveguide, wherein the first nanograting diffracts the incoming light, the waveguide totally reflects the light diffracted by the first nanograting, and the second nanograting diffracts the totally reflected light to guide the light from the waveguide to the visible area, wherein the first nanograting of each layer of the transparent light field lenses has different orientation angles and / or periods, and the second nanograting of each layer of the transparent light field lenses has different orientation angles and / or periods.

7. The device of claim 1, wherein: The virtual-real fusion unit includes a prism, a waveguide and a nano-grating arranged inside the waveguide, wherein the prism refracts the incident light into the waveguide, the waveguide totally reflects the refracted light, and the nano-grating diffracts the totally reflected light to guide the light from the waveguide to the visible area.

8. The device of claim 1, wherein: The virtual-real fusion unit includes a prism, a waveguide and a pair of reflectors arranged inside the waveguide, wherein the prism refracts the incident light into the waveguide, the waveguide totally reflects the refracted light, and the reflector diffracts the totally reflected light to guide the light from the waveguide to the visible area.

9. The device of claim 1, wherein: The virtual-real fusion unit comprises a first waveguide lens, a second waveguide lens, a first group of nanogratings, a second group of nanogratings and a third group of nanogratings, wherein the first group of nanogratings is located between the first waveguide lens and the second waveguide lens, the second group of nanogratings is located on a surface of the second waveguide lens away from the first waveguide lens, the third group of nanogratings is located on the second group of nanogratings, and the first group of nanogratings, the second group of nanogratings and the third group of nanogratings have different orientation angles and / or periods.

Images