True 3D optical display system with enhanced depth of field

Abstract

This application relates to the field of 3D display, and more specifically, to a true 3D optical display system with enhanced depth of field. The system includes components such as a display unit array, a beam splitter, a projection unit, and a control unit. The display unit array projects light, which, after passing through the beam splitter, is driven by the control unit to project corresponding images into different transitional viewing areas. The real images of the transitional viewing areas relative to the projection unit are arranged with small spacing to achieve true 3D display. By utilizing the projected dimensions of the images of the display units relative to the projection unit in the display depth direction, the display depth of field is expanded, making it particularly suitable for fields such as head-up displays.

Description

Technical Field

[0001] This application relates to the field of three-dimensional image display technology, and more specifically, to a true three-dimensional optical display system with enhanced depth of field. Background Technology

[0002] Traditional two-dimensional (2D) displays lose depth information, while three-dimensional (3D) displays, which can express spatial depth information, compensate for this deficiency. However, traditional stereoscopic 3D displays face the problem of visual fatigue caused by focal-verbose conflict (VAC). To overcome this problem, researchers have developed various VAC-free display technologies that can overcome VAC. Among them, the multi-beam superposition technique has received considerable attention. Based on this approach, at least two beams enter the pupil of any observer along different paths through any display point; driven by binocular convergence, the superimposed light distribution at the display point draws the observer's focus to that display point, thus overcoming the focal-verbose conflict. Integrated imaging, multi-view displays, and compressed light fields all follow this type of technique to implement VAC-free 3D displays.

[0003] However, during the process of multi-beam superposition, each superimposed beam has a certain divergence angle; the divergence caused by this divergence angle reduces the attraction of the superimposed light spot at a larger point off the screen to the observer's eye focus, thus resulting in a limited display depth of field. Summary of the Invention

[0004] The purpose of this application is to overcome the shortcomings of existing technologies and provide a true 3D optical display system with enhanced depth of field. This application projects small-pitch viewing areas through a beam splitter. Through any display point, each eye can receive at least one beam of light incident in different directions, thereby achieving VAC-free display with multiple beams superimposed. To increase the display depth of field, the image of the display screen is designed to be tilted non-perpendicularly to the viewing direction. The depth of field is increased by projecting the image itself onto the viewing direction at a non-zero size, thus achieving a large depth-of-field VAC-free display.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] A depth-enhanced true 3D optical display system, including:

[0007] The display unit array includes multiple display units capable of independently projecting light information.

[0008] The beam splitter includes multiple grating units and is placed corresponding to the display unit array, so that the light projected by different display units or their reverse extensions are guided by their respective corresponding grating units and converge toward their respective transition viewing areas.

[0009] The projection unit is capable of forming a magnified virtual image of the display unit array and a real image of each transition viewing area;

[0010] The control unit, connected to the display unit array, controls the loading of light information into each display unit, which is the projected light information of the scene to be displayed along its corresponding projection vector.

[0011] Wherein, the projection radius corresponding to any display unit is the transmission path of the light beam projected by the corresponding grating unit and incident on the corresponding effective viewing area of ​​the display unit. The effective viewing area refers to the real image formed by the projection part of each transitional viewing area.

[0012] The optical display system is configured such that at least two light beams are incident on any observer's pupil within the effective viewing area, passing through any display point.

[0013] Furthermore, the display unit array contains different display units, which correspond to different image distances via the projection section. The image of the display unit array with respect to the projection section is tilted non-perpendicularly to the viewing direction.

[0014] In the above scheme, by cooperating with the display unit array and the projection unit, the image of the display unit array about the projection unit is designed to be tilted non-perpendicularly to the viewing direction, thereby increasing the depth of field.

[0015] Preferably, the depth-enhanced true 3D optical display system further includes an aperture array, wherein each aperture of the aperture array is placed corresponding to each grating unit of the beam splitter, so as to adjust the light-transmitting aperture size of the corresponding grating unit.

[0016] Preferably, the beam splitter is a cylindrical lens array, a slit array, a two-dimensional lens array, a two-dimensional aperture array, or a two-dimensional micro / nano structure array;

[0017] When the beam-splitting grating is a two-dimensional micro-nano structure array, the micro-nano structure units in the two-dimensional micro-nano structure array serve as grating units. Each micro-nano structure unit in the two-dimensional micro-nano structure array and each display unit in the display unit array are placed in a one-to-one correspondence, guiding the light emitted from each corresponding display unit to be projected into the corresponding transition viewing area.

[0018] Preferably, the display unit is a minimal surface structure in which the emitted light information can be independently controlled.

[0019] Preferably, the display units of the display unit array are located on different sub-screens, and adjacent sub-screens are not coplanar, wherein the grating units corresponding to different sub-screens constitute the beam splitting grating.

[0020] Preferably, at least one of the sub-screens is equipped with a corresponding grating unit.

[0021] Preferably, the position and spacing of the grating units of the beam splitter are controlled to change under the drive of the control unit.

[0022] Preferably, when each grating unit has a corresponding focal length, its focal length can be controlled to change under the drive of the control unit.

[0023] Preferably, each of the O adjacent grating units corresponds to an O distinct orthogonal characteristic. Each grating unit allows the corresponding orthogonal characteristic light from the O orthogonal characteristic light to pass through, but blocks the other (O-1) non-corresponding orthogonal characteristic light, where O≥2.

[0024] Preferably, each grating unit corresponds to a display unit block, and each display unit block emits orthogonal characteristic light corresponding to the grating unit.

[0025] Preferably, in the display unit array, along at least one direction, O adjacent display units respectively emit the O types of orthogonal characteristic light.

[0026] Preferably, the orthogonal characteristic is a linear polarization characteristic with mutually perpendicular polarization directions, or an optical rotation polarization characteristic composed of left-handed and right-handed polarization, or a frequency characteristic of different colors, or a temporal characteristic that allows light to pass through or emit light at different time points of the same time period, or a combination of two or more of the orthogonal characteristics.

[0027] Preferably, each aperture of the aperture array is composed of more than one sub-aperture, and each sub-aperture of the same aperture allows light with different orthogonal characteristics to pass through.

[0028] Preferably, each sub-aperture of the same aperture is opened at different times.

[0029] Preferably, each sub-aperture of the same aperture allows light of different colors to pass through, or allows light with different polarization characteristics to pass through.

[0030] Preferably, the depth-enhanced true 3D optical display system further includes a directional backlight structure that can cyclically provide backlight to the display unit array along different directions.

[0031] Preferably, the depth-enhanced true 3D optical display system further includes a directional backlight structure capable of providing backlight for the display unit array. The display unit array is a reflective device. The beam splitter does not have a beam splitting function for the incident backlight, but it has a beam splitting function for the outgoing light modulated by the display unit. This beam splitting function refers to the function of guiding the projected light of different display units or their reverse extensions to converge towards their respective corresponding transition viewing areas.

[0032] Preferably, the beam splitter is a composite structure of a cylindrical lens array and a compensation unit;

[0033] The composite structure acts as a uniform refractive index plate for one type of characteristic light and performs a beam splitting function for another type of characteristic light. The incident backlight is the one type of characteristic light, and the display unit array modulates the emitted light as the other type of characteristic light. The beam splitting function refers to the function of guiding the projected light from different display units or their reverse extensions to converge towards their respective corresponding transition viewing areas.

[0034] Preferably, the display unit array is a micro-nano structure device. This micro-nano structure device has angle selectivity, does not have a beam splitting function for incident backlight, but has a beam splitting function for the modulated outgoing light of the display unit incident in other directions. This beam splitting function refers to the function of guiding the projected light of different display units or their reverse extension lines to converge towards their respective corresponding transition viewing areas.

[0035] Preferably, the tilt angle formed by the display unit array with respect to the image of the projection section and the viewing direction is... θ The range is 5° to 45°

[0036] Preferably, the display unit array is a transparent device.

[0037] Preferably, the beam splitter is a composite structure of a cylindrical lens array and a compensation unit, and the system further includes a polarization selection device;

[0038] The composite structure acts as a uniform refractive index plate for one type of characteristic light and performs a beam splitting function for another type of characteristic light. The polarization selection device only allows the one type of characteristic light component in the ambient light to pass through and be incident on the beam splitting grating, while blocking the other type of characteristic light. The beam splitting function refers to the function of guiding the projected light from different display units or their reverse extensions to converge towards their respective corresponding transition viewing areas.

[0039] Preferably, the beam splitter can alternately present two different states under the drive of the control unit: a state with beam splitting function and a state without beam splitting function. The system also includes a controllable blocking device, which simultaneously allows external ambient light to enter the beam splitter when the beam splitter is in the state without beam splitting function.

[0040] The display unit array loads the relevant information only when the beam splitter is in the state of beam splitting function. The beam splitting function refers to the function of guiding the projected light of different display units or their reverse extensions to converge towards their respective transition viewing areas.

[0041] Preferably, each grating unit corresponds to N b A display unit block, the N b The beams projected by each display unit block, or their reverse extensions, respectively cover the corresponding areas.N b A transition eyebox, where positive integers N b ≥2;

[0042] Wherein, the adjacent display unit block corresponding to any raster unit is ( n × N b ) display unit blocks are spaced apart, where positive integers n ≥1.

[0043] Preferably, the N b Each transition eyebox, with respect to the image of the projection section, serves as an effective eyebox;

[0044] Among them, through N b The emitted light from at least two of the effective eye boxes covers both of the observer's eyes.

[0045] Preferably, it also includes a pupil tracking unit connected to the control unit. Based on the position of the observer's eye determined by the pupil tracking unit, the control unit can adjust the display unit corresponding to each grating unit to generate a corresponding effective eye box.

[0046] Preferably, the projection part is a single optical element or a combination of multiple optical elements.

[0047] Preferably, in the display unit array, the emitted light is guided to adjacent display units in different viewing areas, and along each arrangement direction of the display units, there are more than one adjacent display unit emitting light of the same color.

[0048] Preferably, the control unit controls each display unit to load light information, which is the corresponding color component in the light information projected onto the scene to be displayed along its corresponding projection vector.

[0049] Compared with existing technologies, the advantages of this application are: for VAC-free displays achieved through beam splitting gratings, by non-perpendicularly placing the image of the display screen relative to the viewing direction, the projection size of the image itself in the viewing direction is utilized to expand the display depth; combined with the magnification of the projection unit, a large depth-of-field VAC-free display is achieved. The related display system is particularly suitable for head-up displays. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the generation of the real transition view zone based on a cylindrical lens type beam splitter grating.

[0051] Figure 2 This is an example diagram showing the positional relationship between the display unit and the cylindrical lens grating unit, as well as the color arrangement of the display unit.

[0052] Figure 3 This is a schematic diagram of a slit-type beam splitter.

[0053] Figure 4 This is a schematic diagram of virtual transition view generation based on a cylindrical lens type beam splitter grating.

[0054] Figure 5 This is a schematic diagram of the effective display area when the display unit array is placed perpendicular to the viewing direction.

[0055] Figure 6 This is a schematic diagram of a projection section that includes multiple components.

[0056] Figure 7 This is a schematic diagram of the effective display area when the display unit array and the viewing direction are not perpendicular.

[0057] Figure 8 This is a schematic diagram illustrating the non-perpendicular placement of the display unit array with respect to the image of the projection unit and the viewing direction in a head-up display application scenario.

[0058] Figure 9 These are schematic diagrams (a), (b), (c), and (d) showing the situation where the display unit array is composed of different sub-screens.

[0059] Figure 10 This is a schematic diagram illustrating an example of different orthogonal characteristics between adjacent raster units and adjacent display unit blocks.

[0060] Figure 11 This is a schematic diagram illustrating another example of different orthogonal characteristics corresponding to adjacent raster units and adjacent display unit blocks.

[0061] Figure 12 This is a schematic diagram illustrating an example of adjacent grating units having different orthogonal characteristics.

[0062] Figure 13 This is a schematic diagram illustrating an example of different orthogonal characteristics between adjacent grating units and adjacent display units.

[0063] Figure 14 This is a schematic diagram illustrating another example of different orthogonal characteristics between adjacent grating units and adjacent display units.

[0064] Figure 15 This is a schematic diagram illustrating an example of adjacent display units having different orthogonal characteristics.

[0065] Figure 16 This is a schematic diagram illustrating an example of different orthogonal characteristics corresponding to the timing of all display units.

[0066] Figure 17 A diagram illustrating the principle of using a sub-aperture to improve display resolution.

[0067] Figure 18 This is a schematic diagram illustrating one usage example of a reflective display unit array.

[0068] Figure 19 This is a schematic diagram illustrating another application example of a reflective display unit array.

[0069] Figure 20 This is a schematic diagram illustrating one usage example of a transparent display unit array.

[0070] Figure 21 This is a schematic diagram illustrating another application example of a transparent display unit array.

[0071] Figure 22 This is a schematic diagram of the generation of a discrete distributed real transition eyebox.

[0072] Figure 23 This is a schematic diagram of the effective eyebox distribution in the case of discrete distributed virtual transition eyeboxes. Detailed Implementation

[0073] The accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. The dimensions of the optical components and their relative distances shown in the drawings are also merely illustrative and do not limit the actual dimensions of the optical components and their relative distances in the actual optical structure. It is understandable that some well-known structures and their descriptions may be omitted in the drawings for those skilled in the art. This application increases the depth of field of VAC-free displays by designing the image of the display unit array to be non-perpendicular to the viewing direction.

[0074] Example 1

[0075] Using cylindrical lenses as grating units, a cylindrical lens type beam splitter grating 20 is formed, such as... Figure 1 Example. Along the direction of grating unit arrangement. x ', the spacing between adjacent grating units is b The spacing between adjacent display units on display unit array 10 is p m The spacing of the cylindrical lens optical center distance display unit array 10 is... D b Then in ( m × p m )> b ,and b / ( m × p m )=( D e - D b ) / D e In this case, the light emitted from each display unit of the display unit array 10 will be guided by the beam splitter 20 and directed at a distance of [distance missing] from the display unit array 10. D e On the surface, they converge and form m >1 view area. m This refers to the number of view regions formed. View regions formed by the convergence of light beams are called real transition view regions, and the surface on which they lie is called the real transition view region surface. Figure 1 by m Taking nine real transition view areas as an example, this will be explained, including real transition view areas. RVZ 1. RVZ 2. RVZ 3. RVZ 4. RVZ 5. RVZ 6. RVZ 7. RVZ 8. RVZ 9. Among them, the display unit U 1. U 2. U 3. U 4. U 5. U 6. U 7. U 8. U 9 Corresponding grating units k Each transitions to the real view area RVZ 1. RVZ 2. RVZ 3. RVZ 4. RVZ 5. RVZ 6. RVZ 7. RVZ 8. RVZ 9. Projected beam; display unit U 10 , U 11 , U 12 , U 13 , U 14 , U 15 , U 16 , U 17 , U 18 (in U 15 , U 16 , U17 , U 18 Not in Figure 1 (As shown) via the corresponding grating unit k +1, respectively transitioning to the real view area RVZ 1. RVZ 2. RVZ 3. RVZ 4. RVZ 5. RVZ 6. RVZ 7. RVZ 8. RVZ 9. Projected beam; and so on. Spacing between adjacent real transition viewing zones. e = p m ×( D e - D b ) / D b Then the display unit U 1. U 10 , U 19 , U 28 ,…(in U 19 , U 28 Waiting in Figure 1 (As shown) will transition to the real view area RVZ 1. Project an image; display unit U 2. U 11 , U 20 , U 29 ,…(in U 20 , U 29 Waiting in Figure 1 (As shown) will transition to the real view area RVZ 2. Project an image; and so on, each real transition view will receive its corresponding image. Figure 1 Only a portion of the display unit and a portion of the raster unit are shown. U 14 The subsequent display units, i.e., display units with an index greater than 14, are in Figure 1The depth of field presented by the display unit array 10 and the beam splitter 20 to the real transition viewing area is called the initial depth of field, corresponding to the initial display area in the figure. The beam splitter 20 may be equipped with an aperture array 201, which is composed of apertures; each aperture is placed corresponding to each grating unit of the beam splitter 20 to adjust the aperture size of the corresponding grating unit. Each aperture can be placed in front of, behind, or inside the corresponding grating unit; the aperture size of each aperture can be constant or controllably changed under the drive of the control unit 40; the aperture sizes of different apertures can be the same or different. The beam splitter 20 in the subsequent figures may also be equipped with an aperture array 201, and will not be described again in the figures.

[0076] Figure 1 In this design, the orientation of the raster units is often designed to be tilted relative to the orientation of the display units, such as... Figure 2 As shown in Figure 3, the beam-splitting unit of the beam-splitting grating 20 can also be an array of slits, with slits serving as grating units. Each slit replaces a cylindrical lens in Figure 1, similarly achieving the projection of different images into different real transition viewing areas. Furthermore, the beam-splitting grating 20 can also be composed of two-dimensionally arranged grating units, such as a two-dimensional lens array or a two-dimensional aperture array. Similarly, along different directions of the grating unit arrangement... Figure 1 The beam splitter grating 20 can also be a two-dimensional micro / nano structure array, in which micro / nano structure units serve as grating units. Each micro / nano structure unit is placed in a one-to-one correspondence with each display unit in the display unit array, guiding the light emitted from each corresponding display unit to be projected into the corresponding transition viewing area. For example, but not limited to, any micro / nano structure unit can be a metasurface structure.

[0077] Each display unit in the display unit array 10 is a surface structure whose emitted light intensity can be independently adjusted, i.e., its emitted light information can be independently projected. For example, a composite structure formed by combining RGB sub-pixels (i.e., pixels in a conventional RGB display device); or a minimum surface structure with adjustable emitted light intensity. The minimum surface structure with adjustable emitted light intensity can use sub-pixels from existing display devices, such as, but not limited to: a single R sub-pixel, a single G sub-pixel, or a single B sub-pixel composed of a liquid crystal light valve requiring backlight and a corresponding color filter; or an OLED emitting monochromatic light; or an LED emitting monochromatic light; or an OLED emitting white light and a corresponding color filter forming a unit OLED; or an LED emitting white light and a corresponding color filter forming a unit LED; or a multi-color stacked structure composed of layers emitting R, G, and B light respectively. Here, R, G, and B refer to red, green, and blue light commonly found in display devices. Here, we take a display unit array 10, constructed from display units emitting R-light, G-light, and B-light, as an example. Obviously, it can also be constructed from display units emitting other colors. Each display unit can also be a surface structure with cyclically and sequentially incident backlights of different colors and adjustable emitted light intensity, such as a liquid crystal light valve with sequentially incident backlights of different colors, or other controllably emitting colored light—the smallest non-divisible light-emitting structure. Each display unit can also be a single light spot projected by a projection device onto a scattering surface, or a combination of multiple such light spots. In fact, the display unit array 10 can be various types of display devices. The display units of the display unit array 10 can be arranged in various possible ways. For example, taking a display unit array 10 constructed from display units emitting R light, G light, and B light as an example, along one dimension, its display units can be arranged in an RGBRGB… pattern (RGB repeating), or an RRR…GGG…BBB…RRR…GGG…BBB… pattern (RRR…GGG…BBB… repeating), or an arrangement of R, G, and B light-emitting points in a triangular pattern as a cycle, or a non-periodic arrangement, and various other possible arrangements. Figure 2 Taking the display unit within the dashed frame in the left figure as an example, along x The top right image illustrates an RGBRGB... arrangement, while the bottom right image illustrates an RRGGBB... arrangement; along... y In this example, display units in the same column emit light of the same color. The color of the light emitted by other display units can be determined based on a similar arrangement rule. Figure 2 The upper right and lower right images only illustrate two limited arrangements; in reality, various possible arrangements exist, which will not be exhaustive. Among these, the arrangement where adjacent display units emit the same color light along a two-dimensional direction is advantageous for increasing the minimum color filter unit size when color selection is based on color filters. For example, Figure 2In the arrangement shown in the lower right figure, along the two arrangement methods of the display units, each of the two adjacent display units, for a total of four adjacent display units, can correspond to the same color filter. At this time, the smallest color filter unit size is twice the display unit spacing in both directions. Figure 2 In the lower right image, along the indicated path x The two adjacent display units are in the direction shown. y All pixels in the direction emit light of the same color, which can also be covered by a corresponding color filter. Clearly, Figure 2 In the middle, two-dimensional arrangement of display units U 10 , U 11 , U 12 , U 13 , U 14 , U 15 , U 16 , U 17 , U 18 , is the corresponding grating unit k The emitted light, with a +1 value, is guided to m adjacent display units in m=9 viewing zones, forming a periodic structure of display units. When they emit the same color light, the size of the color filter unit can be larger. In this case, considering the requirement that the view corresponding to any viewing zone is usually in color, the periodic structure of adjacent display units is optimally designed to emit different colors of light along at least one direction. For example, Figure 2 In the middle, the display unit U 1. U 2. U 3. U 4. U 5. U 6. U 7. U 8. U The display unit consists of a periodic structure of 9 units, and the display unit... U 10 , U 11 , U 12 , U 13 , U 14 , U 15 , U 16 , U 17 , U18 The display unit consists of a periodic structure, configured to emit light of different colors; or / and the display unit U 19 , U 20 , U 21 , U 22 , U 23 , U 24 , U 25 , U 26 , U 27 The periodic structure of the display unit and the display unit U 10 , U 11 , U 12 , U 13 , U 14 , U 15 , U 16 , U 17 , U 18 The periodic structure of the display units is configured to emit light of different colors. This pattern continues. When multiple adjacent display units arranged in a two-dimensional array emit light of the same color, and the color of their emitted light is achieved by filtering with the same color filter, considering the accurate alignment of each color filter and the corresponding multiple display units, the display units at the edges of the block structure composed of adjacent display units of the same color can be turned off or removed to reduce crosstalk caused by alignment deviations between the color filters and the display units.

[0078] In the above process, the number of light intensity grayscale values ​​that a display unit can present is unlimited. Under the drive of the control unit 40, the light intensity that a display unit can present can be 2-valued (for example, it can only present two states, 0 or 1), or 3-valued (for example, it can present three states, 1, 1 / 2 or 0), or it can be other grayscale values ​​(for example, 256 grayscale values).

[0079] The aforementioned real transition view regions can also be replaced by virtual transition view regions. For example... Figure 4 , in (m× p m )< b , and (m× p m ) / b= De / ( D e + D b In the case of [condition], the light emitted from each display unit of the display unit array 10 passes through the backward extension line of the light emitted from the beam splitter 20, at a distance of [distance] from the display unit array 10. D e On the surface, they converge and form m Each viewing region is formed by the convergence of the backward extensions of the light beams. This type of viewing region is called a virtual transition viewing region, and the surface on which it is located is called the virtual transition viewing region surface. Figure 4 by m Taking six virtual transition view areas as an example, this will be explained in detail. VVZ 1. VVZ 2. VVZ 3. VVZ 4. VVZ 5. VVZ 6. Among them, the display unit U 1. U 2. U 3. U 4. U 5. U 6 Corresponding grating units k The backward extensions of the projected beams point to the virtual transition viewing area. VVZ 1. VVZ 2. VVZ 3. VVZ 4. VVZ 5. VVZ 6; Display unit U 7. U 8. U 9. U 10 , U 11 , U 12 via the corresponding grating unit k The backward extensions of the beam projected by +1 point to the virtual transition viewing area. VVZ 1. VVZ 2. VVZ 3. VVZ 4. VVZ 5. VVZ 6; and so on. Spacing between adjacent virtual transition view zones. e = p m ×( D e + D b ) / D b Then the display unit U 1.U 7. U 13 , U 19 ...will transition to a virtual view area VVZ 1. Virtually project an image; display unit U 2. U 8. U 14 , U 20 ...will transition to a virtual view area RVZ 2. A virtual image is projected; and so on, each virtual transition view will virtually correspond to a different image. Figure 4 Only a portion of the display unit and a portion of the raster unit are shown. U 15 The subsequent display units, i.e., display units with a subscript greater than 15, are in Figure 4 Not shown in the diagram. At this time, the depth of field presented by the display unit array 10 and the beam splitter 20 relative to each virtual transition viewing area is also called the initial depth of field, corresponding to the initial display area in the diagram. Similarly, the arrangement direction of the grating units is often designed to be tilted relative to the arrangement direction of the display units, such as... Figure 2 As shown.

[0080] The projection unit 30 is introduced to form a magnified virtual image of the display unit array 10, such as... Figure 5The aforementioned transitional viewing areas (including the virtual or real transitional viewing areas) are projected into real images by the projection unit 30. These real images are named effective viewing areas, and the image corresponding to the corresponding transitional viewing area can be received at each effective viewing area. The control unit 40 is signal-connected to the display unit array 10 to drive each display unit to load light information, which is the projected light information of the scene to be displayed along its corresponding projection vector. The projection vector of a display unit is the transmission path of the light beam projected by that display unit through the corresponding grating unit and incident on the corresponding effective viewing area. When the light projected by each display unit to the observation area has only a specific color, the control unit 40 controls each display unit to load light information, which is the corresponding color component in the projected light information of the scene to be displayed along its corresponding projection vector. During the information loading process, the loading information of each display unit can also be the product of the projected light information of the display scene along its corresponding projection vector and a coefficient. For example, this coefficient is a function of the distance between the principal ray and the corresponding preset viewpoint when the beam projected by the corresponding display unit onto the corresponding effective viewing area. Specifically, this function is (1 - (the ratio of this distance to the spacing between the corresponding preset viewpoints)). The preset viewpoint corresponding to a display unit is a point preset within the corresponding effective viewing area of ​​that display unit, and along the direction of the viewing area arrangement, it is often taken as the midpoint of the effective viewing area. Meanwhile, the transmission path in "the projection radius of a display unit is the transmission path of the beam projected by the display unit through the corresponding grating unit and incident on the corresponding effective viewing area" is often chosen as the transmission path of the principal ray in the beam projected by the corresponding grating unit and incident on the corresponding effective viewing area; however, it can also be the transmission path of any ray in the beam projected by the corresponding grating unit and incident on the corresponding effective viewing area. In actual information loading, often at a certain point in time, a 3D image model of the corresponding display scene is constructed in 3D software. Then, using cameras set up in different viewpoints, the light information required by the corresponding display unit for each viewpoint is extracted from the view information captured by each camera. If necessary, weighted algorithms are used to obtain the image required by the display unit array 10, which is then loaded synchronously. When the display scene is relatively simple, especially when the display scene is composed of graphics distributed on different depth planes, and the corresponding depth information is known (i.e., the depth map information is known), the view information corresponding to each viewpoint can be calculated based on the geometric relationship between the position of each viewpoint, the position of each display unit array 10 and its image, and the depth of the display scene. Alternatively, from a captured view, the view information corresponding to different viewpoints can be calculated based on the geometric relationship between the position of each viewpoint, the position of each display unit and its image, the depth of the display scene, and the viewpoint position of the captured view. When the distance between adjacent effective viewpoints is no greater than the diameter of the observer's pupil, and the generated effective viewpoint can cover both eyes of the observer, VAC-free 3D display can be achieved based on multi-beam superposition. Figure 5 Let's take the virtual transition view area as an example for explanation.m =6 virtual transitional view areas VVZ 1. VVZ 2. VVZ 3. VVZ 4. VVZ 5. VVZ 6 correspond to the effective visual area. In reality, to cover both eyes of the observer, m They tend to take relatively large values. Figure 5 In the structure shown, a single lens is used as the projection unit 30; in this case, the optical axis direction of the lens, the z-direction, is usually collinear with the observer's viewing direction. The final display area, i.e., the effective display area, is the magnified area of ​​the initial display area by the projection unit 30, such as... Figure 5 .but Figure 5 In the center, the plane where the display unit array 10 is located is set perpendicular to the viewing direction, that is, the vertical direction of the plane where the display unit array 10 is located. z 'Direction, and direction of observation' z The initial display area is limited in size along the viewing direction, resulting in a limited effective display area along the viewing direction, i.e., a limited depth of field. Figure 5 Let's take the effective viewing area corresponding to the virtual transition viewing area as an example. In fact, it can also be the effective viewing area corresponding to the real transition viewing area; in this case, each effective viewing area is usually a reduced real image corresponding to the real transition viewing area.

[0081] Figure 5 The single-lens projection section 30 can also be replaced by a combination of multiple optical devices, for example... Figure 6 In this design, the projection unit 30 is composed of a freeform surface reflector 302 and a car windshield 301. This type of projection unit 30 is commonly found in vehicle head-up displays (HUDs). Obviously, the projection unit 30 can be a combination of various devices, such as the various device combinations commonly found in head-up displays, as long as its function is to form a magnified virtual image of the display unit array 10 and a real image of the transition viewing area. Figure 6 In the middle, the image of the display unit array 10 about the projection unit 30 is displayed. I 10 The vertical direction of the plane z The direction coincides with the observation direction z. Figure 6 middle, I 20 It is the image of the beam splitter 20 with respect to the projection section 30.

[0082] To further increase the final display depth of field, this application, based on the above, designs the image of the display unit array 10 to have a tilt angle relative to the viewing direction. θ Non-zero, non-vertical placement, such as Figure 7 The non-zero θ The optimal range for this value is 5° to 45°. For example, Figure 7 In the example shown, the tilt angle θ The angle is 45°. At this time, different display units exist on the display unit array 10, each corresponding to a different image distance via the projection section 30. In this case, the projection of the image of the display unit array 10 onto the viewing direction is a non-zero value. Δ The observation direction described in this application is a preset direction, determined along the depth of field. Therefore, the non-zero... Δ The introduction of '' can lead to an expansion of the effective display area along the viewing direction, i.e., an expansion of the display depth. Simultaneously, to ensure VAC-free display, the spacing of the effective viewing area along at least one direction on the preset plane where the observer's eyes are located is no greater than the pupil diameter. The initial display area is optimally placed within one focal length of the projection unit 30. Figure 7 The single-lens projection section 30 can also be replaced by multiple optical devices, such as... Figure 8 In the middle, the projection part 30 is composed of a freeform surface reflector 302 and a car windshield 301. Figure 8 middle, I 10 and I 20 These are the images of the display unit array 10 and the beam splitter 20 with respect to the projection unit 30, respectively. The image of the display unit array 10 with respect to the projection unit 30. I 10 The vertical direction of the plane z The angle between the z-direction and the observation direction is non-zero. θ ,For example, Figure 8 In the example shown, the tilt angle θ It is 5°. Figure 7 and Figure 8 In the middle, non-zero included angle θ The orientation is not limited and can be set according to actual needs. In other embodiments, the non-zero included angle... θ The value can be, for example, 10°, 15°, 20°, 25°, 30°, 35°, or 40°.

[0083] The display units of the aforementioned display unit array 10 can also be located on different sub-screens, with adjacent sub-screens not coplanar, such as... Figure 9 The sub-screens 10-1, 10-2, 10-3, or 10-4 are in the display unit array 10. The grating units corresponding to each sub-screen of the display unit array 10 form the beam splitting grating 20. Figure 9 (b) and Figure 9 (c) Sub-screens 10-1 and 10-2 correspond to grating units 20-1 and 20-2, respectively. Some sub-screens may not have corresponding grating units, such as... Figure 9 (a) Sub-screen 10-3 and Figure 9 (d) Sub-screen 10-1, at this time, this part of the sub-screen can display two-dimensional images. In fact, when all display units of the display unit array 10 are coplanar, part of its area can also be designed without corresponding grating units, that is, two-dimensional display can be performed based on this part of the area. Figure 9 In this context, different subscreens can be arranged adjacent to each other, such as... Figure 9 (a) and Figure 9 As shown in (b), they can also be arranged in a non-contact manner, such as Figure 9 (c) shows the following. Additionally, the grating parameters of the display unit array 10, or the grating units corresponding to each of its sub-screens, including the grating unit spacing, the position of each grating unit, and the focal length, can be set individually or controlled and adjustable under the drive of the control unit 40. For example, but not limited to, the grating unit spacing, and / or the grating unit focal length, and / or the grating unit position of a liquid crystal cylindrical lens grating, or the grating unit spacing, and / or / or the grating unit position of a liquid crystal slit grating. In this case, the pupil tracking unit 70, which is connected to the control unit 40 by a signal, adjusts the beam-splitting grating parameters in real time based on the real-time position of the observer's pupil determined by the pupil tracking unit 70, to ensure that the effective viewing area tracks and covers the observer's eye. In this document, VAC-free display can be implemented as long as more than one beam of light enters any pupil of the observer through any display point; a specific viewpoint is not required.

[0084] Adjacent grating units can also be configured as O ≥ 2 adjacent grating units, each corresponding to O distinct orthogonal characteristics. Each grating unit allows light with the corresponding orthogonal characteristic to pass through, but blocks light with non-corresponding orthogonal characteristics. This blocking does not mean 100% blocking; rather, it means that light leakage, as noise, has a tolerable impact on display quality. The orthogonal characteristic refers to an identifiable characteristic, that is, a grating unit with one orthogonal characteristic allows light with the corresponding orthogonal characteristic to pass through, but blocks light with non-corresponding orthogonal characteristics. Such orthogonal characteristics include, but are not limited to: linear polarization characteristics with mutually perpendicular polarization directions, or cyclopolarization characteristics consisting of left-handed and right-handed polarization, or frequency characteristics of different colors, or temporal characteristics that allow light to pass through or emit light at different points in the same time period, or combinations of two or more of the above orthogonal characteristics. In this case, the display units corresponding to each grating unit form a display unit block; each display unit block emits only light that is allowed to pass through by the corresponding grating unit and blocked by the O-1 adjacent non-corresponding grating units of the corresponding grating unit. Figure 10 The linear polarization characteristics “·” and “-”, which are perpendicular to each other in polarization direction, are used as orthogonal characteristics. Figure 10 Only two adjacent grating units (O=2) are shown. k and k +1, where the grating unit k Only "·" light is allowed to pass through, while "-" light is blocked; grating unitk +1 only allows "-" light to pass through, blocking "·" light. Other grating units are configured similarly, for example, along... x 'Negative direction, not shown grating unit' k +2 only allows "·" light to pass through, blocking "-" light. (See grating unit, not shown.) k +3 allows only "-" light to pass through, blocking "·" light, and so on. The linear polarization characteristics of each grating unit can be implemented through various methods, such as, but not limited to, bonding polarizers with corresponding characteristics, or making each grating unit itself a micro / nano structure, allowing only light with corresponding orthogonal characteristics to pass through. Grating unit k corresponding x 'To the display unit U 1. U 2. U 3. U 4. U 5. U 6, as the grating unit k The corresponding display unit block of part of the display unit (along) x (If the display unit block also contains other display units, then the raster unit is located in the vertical direction.) k The corresponding display unit block emits only "·" light; raster unit k+1 Corresponding display unit U 7. U 8. U 9. U 10 , U 11 , U 12 As the grating unit k +1 corresponds to a portion of the display unit block (along...) x (If the display unit block also contains other display units, then the raster unit is located in the vertical direction.) k The corresponding display unit block emits only "-" light, and so on. In this case, the light emitted by a display unit is blocked by the adjacent grating unit of the corresponding grating unit, thereby eliminating some crosstalk light information next to the effective viewing area. Figure 11 In the example shown, adjacent O=3 grating units are given different frequency characteristics, that is, color orthogonal characteristics. Figure 11 Only three adjacent grating units (O=3) are shown. k , k +1 and k +2, where the grating unit k Only R-beams are allowed to pass through, while G-beams and B-beams are blocked; grating unit k +1 allows only G light to pass through, blocking R and B light; grating unit k+2 only allows B-beams to pass through, blocking R-beams and G-beams. Other grating units are configured similarly. For example, along... x 'Negative direction, not shown grating unit' k +3 allows only R-beams to pass through, blocking G-beams and B-beams; grating unit not shown. k +4 only allows G light to pass through, blocking R and B light; grating unit not shown. k +5 allows only B light to pass through, blocking R and G light; and so on. The frequency characteristics of each grating unit can be implemented by various methods, such as, but not limited to, bonding corresponding color filters. Grating unit that allows R light to pass through. k The corresponding display unit U 1. U 2. U 3. U 4. U 5. U 6. ... constitute the grating unit k The corresponding display unit block (here "..." refers to the edge) x (The vertical display unit is not shown; similar units will not be repeated below.) It only projects R-light; the grating unit allows G-light to pass through. k +1, its corresponding display unit U 7. U 8. U 9. U 10 , U 11 , U 12 ... make up the grating unit k The display unit block corresponding to +1 projects only G light; the grating unit allows B light to pass through. k +2, its corresponding display unit U 13 , U 14 , U 15 , U 16 , U 17 , U 18 ... make up the grating unit k The display unit block corresponding to +2 only projects B light; and so on.

[0085] A display unit can also be a minimal surface structure that emits light of more than one different color. For example, but not limited to, a structure consisting of three superimposed emissive layers that emit R, G, and B light respectively, with the intensity of each emissive layer controllable. Alternatively, it can be an emissive point where R, G, and B light are incident sequentially, such as a liquid crystal light valve with controllable emission intensity. In this case, different colored light from the same display unit will exit through grating units with different color characteristics and enter the effective viewing area along different paths. Obviously, this example uses R, G, and B colors, but other colors could also be used.

[0086] Figure 12 In the example shown, adjacent O=2 grating units are given timing characteristics. Figure 12 Only three adjacent grating units are shown. k , k +1 and k +2, other grating units are named according to the same rules; among them, grating units… k , k +2 、k +4 、 …only within a time period t~t+Δt time point t Light is allowed to pass through during the corresponding time period, grating unit... k +1、 k +3 、k +5 、 …only within this time period t~t+Δt Time point t+Δt The time period corresponding to / 2 allows light to pass through. Therefore, at that time point... t During the corresponding time period, all display units in the display unit array 10 are respectively assigned to the raster units that are activated at that time. Specifically, at a given time point... t Corresponding time period, grating unit k Corresponding display unit U i , U i+1 … U i+11 ..., grating unit k +2 corresponds to the display unit. U i+12 , U i+13 … U i+23 ...and so on. At a certain point in time... t+Δt / 2 corresponds to the time period, and similarly, all display units in the display unit array 10 are assigned to the raster units that are turned on at this time... k +1、 k+3, ... In this case, any display unit will correspond to different grating units at different points in the same time period. Through time-division multiplexing, the utilization rate of the display unit is improved. The viewing areas projected by grating units with different orthogonal characteristics can overlap or be spatially misaligned. As long as at least two beams of light enter either eye of the observer through a display point, VAC-free display can be achieved.

[0087] The above Figures 10 to 12 In a display unit, a raster unit with orthogonal characteristics has its corresponding display units arranged adjacent to each other to form a corresponding display unit block. A raster unit with orthogonal characteristics can also have its corresponding display units interleaved with those of other raster units. Figure 13 Taking frequency characteristics as an example, it only shows three adjacent grating units (O=3). k , k +1、 k +2, other grating units are named according to the same rules. (The grating unit...) k Allows "R" light to pass through, blocks "G" and "B" light; grating unit k +1 allows "G" light to pass through while blocking "R" and "B" light; grating unit k +2 allows "B" light to pass through, while blocking "R" and "G" light; and so on. This applies along the direction of the grating unit arrangement. x' The three adjacent O=3 display units emit "R" light, "G" light, and "B" light respectively. Therefore, adjacent grating units with different orthogonal characteristics have their corresponding display units interleaved, as detailed in the following diagram. Figure 13 Example. Figure 13 middle, G i The display unit with serial number i that emits G light is specified; the naming of other display units is set in the same way. Figure 14 Taking the mutually perpendicular linear deflection characteristics "·" and "-" as examples, display units that emit "·" and "-" light respectively are arranged in an interlaced manner, such as... Figure 15 For example, the aforementioned orthogonal characteristics can also be combined with each other. For instance, when adjacent grating units have linear polarization characteristics "·" and "-" respectively, under the control of the introduced polarization characteristic timing adjustment unit 80, the display unit array 10 sequentially emits "·" light and "-" light, as shown below. Figure 16 As shown.

[0088] The aforementioned display unit array 10 can also be designed with directional backlights corresponding to the timing of incident light along different directions. Figure 17 Taking the backlight from the three directions of the directional backlight structure 60 as an example, it occurs within one time period. t~t+Δt Three time points t , t+Δ t / 3、t+ 2 Δt / 3, incident separately. At this time, the same display unit, under backlighting from different directions, is equivalent to being emitted from different positions in the display unit array 10. Specifically, taking... Figure 17 Display unit U For example, 4. At a certain point in time. t The backlight incident along direction 1 passes through the display unit. U 4. After modulation, the light is incident on the corresponding grating unit along path 1'. k Then through the grating unit k The control, along path 1'', is incident on the corresponding viewing area VZ', which is equivalent to a point on the display unit array 10. U The projected beam at '4(t). Where, point U '4(t)' is the intersection of the reverse extension of path 1'' and the display unit array 10. At time point... t+ 2 Δt / 3, Backlight incident along direction 3, passes through the display unit U 4. After modulation, the light is incident on the corresponding grating unit along path 1'''. k Then through the grating unit k The control, along path 1'''' incident on the corresponding viewing area VZ', is equivalent to a point on the display unit array 10 U The projected beam is ''4(t+2Δ / 3). Where, point U '4(t+2Δ / 3) is the intersection of the reverse extension of path 1 and the display unit array 10. At time point... t+Δt / 3, incident display unit along direction 2 U The backlight of position 4, after passing through the corresponding grating unit, enters the corresponding viewing area VZ' along another path, which is equivalent to exiting from another point on the display unit array 10. Therefore, under the action of different timing backlights, the same display unit is equivalent to projecting light beams from different positions on the surface of the display unit array 10, effectively increasing the number of spatial light beams that can be reconstructed. In this case, a light beam projected by a display unit may correspond to different grating units under different backlight illuminations, such as... Figure 17 Display unit in U 10 The method of increasing display resolution through time-sequential backlighting can also be achieved by time-gating different regions of the light-transmitting aperture in each grating unit. For example... Figure 17 Each aperture in the aperture array 201 is composed of more than one sub-aperture, and each sub-aperture of the same aperture is opened at different time points. Figure 17 Taking an aperture unit consisting of two sub-apertures as an example, specifically, the grating unit k The corresponding aperture, including sub-apertures A k (1) and Ak (2), grating unit k The aperture corresponding to +1 includes the sub-aperture. A k+1 (1) and A k+1 (2), and so on. The two sub-apertures of each aperture open at different points in the same time period. Thus, light projected from a display unit, passing through different sub-apertures of the aperture corresponding to the corresponding grating unit, enters the same effective viewing area along different paths, equivalent to light from different points on the surface of the display unit array 10. The aforementioned "point in time" refers to a time period including that point. The sub-apertures of the same aperture can also be designed to allow other different orthogonal light components to pass through, especially when the light emitted from the display unit includes these different orthogonal light components. For example, the sub-apertures of the same aperture allow different colors of light to pass through. In this case, if the light emitted from the display unit contains these different color light components, the different colors of light from the same display unit will exit through the sub-apertures of the corresponding grating unit with different color characteristics, and enter the effective viewing area of ​​the display unit along different paths; similar to... Figure 17 As shown, this is equivalent to light emanating from different positions on the surface of the display unit array 10. For example, a display unit is a structure composed of three superimposed light-emitting layers that emit R-light, G-light, and B-light respectively, each with controllable emission intensity, or light-emitting points where R-light, G-light, and B-light are incident sequentially (e.g., liquid crystal apertures with controllable emission intensity). Obviously, this example uses R, G, and B colors, but other colors could also be used.

[0089] The display units of the display unit array 10 can be active-emitting, backlit, transmissive, or backlit reflective. When the display unit array 10 is a backlit, reflective device, the beam splitter 20 needs to have the following characteristics: when the backlight enters the display unit array 10 through the beam splitter 20, the incident beams of each display unit have similar divergence angle characteristics. Ideally, the backlight, after passing through the beam splitter 20, remains uniformly incident on the display unit array 10; then, the reflected light modulated by the display unit array 10 is modulated by the beam splitter 20, and the light emitted from different display units is guided to their respective corresponding transition viewing areas. Figure 18As shown in the example, the beam-splitting grating 20 includes a compensation unit 202 and a cylindrical lens array. Backlight with one polarization characteristic is uniformly incident on the reflective display unit array 10 through the beam-splitting grating 20; after being modulated and reflected by the display unit array 10, it exits with another polarization characteristic. For this other polarization characteristic light, the compensation unit 202 and the cylindrical lens array of the beam-splitting grating 20 together perform a beam-splitting function, guiding the projected light from each display unit to its corresponding transition viewing area. Other media, such as optical adhesive, can also be filled between the compensation unit 202 and the cylindrical lens array. Ideally, each display unit in the display unit array 10 can controllably adjust the polarization characteristic of its outgoing light to implement two-dimensional or three-dimensional display as needed, or to implement two-dimensional or three-dimensional display in certain areas of the display unit array 10 as needed. Specifically, for example... Figure 18 The auxiliary unit 202 is a liquid crystal device. This auxiliary unit 202 has different refractive indices for different polarized light. As a result, when the backlight is incident with one polarization state, the compensation unit 202 of the beam splitter 20 and the cylindrical lens array together act as a plate with a uniform refractive index, and the backlight is uniformly incident on the display unit array 10 through it. However, for the other polarized light emitted after modulation by the display unit array 10, the compensation unit 202 of the beam splitter 20 and the cylindrical lens array together act as a beam splitter. For example, the beam splitter 20 is a micro-nano structure device. It does not have a beam splitting function for obliquely incident backlight. As a result, after the backlight is incident on the beam splitter 20, the beam divergence angle is not affected when it is incident on the display unit array 10. However, the light emitted from the display unit array 10 that is incident on the beam splitter 20 perpendicularly or nearly perpendicularly is modulated by the beam splitter 20, and the projected light from each display unit is guided to its respective corresponding transition viewing area. The backlight can also be designed to be incident on the display unit array 10 via a polarization selection device 203, such as... Figure 19 For example, a backlight of one polarization state is reflected by a polarization selection device 203 and enters a beam splitter 20, which acts as a flat plate with a uniform refractive index for the backlight of this polarization state. Then, the incident backlight is modulated by the display unit array 10 and exits as light of another polarization state. The beam splitter 20 performs a beam splitting function for the modulated light of this other polarization state, and the modulated light of this other polarization state is transmitted through the polarization selection device 203.

[0090] The display units of the aforementioned display unit array 10, whose emitted light intensity can be dynamically changed as needed under the drive of the control unit 40, are referred to as dynamic display units. The display unit array 10 can also be composed of static display units, i.e., display units whose emitted light information cannot be changed by the control unit 40. For example, each display unit may be an aperture with different transmittance corresponding to different emitted light intensities, generated by methods such as etching or laser printing, which emits light points after backlight is incident; each aperture corresponds to a specific transmittance, and its corresponding displayed light intensity can similarly be binary or multi-valued. Specifically, for example, the transmittance may be in two states: zero and non-zero, corresponding to two kinds of emitted light intensities; or the transmittance may be in three states: zero, maximum value, and half of the maximum value, corresponding to three kinds of emitted light intensities; and so on. The different transmittances can be achieved, for example, by different aperture areas, or by films with different absorption rates attached within the apertures. The static display unit can also be a reflective surface with different reflectivities corresponding to different emitted light intensities. After backlight is incident, the emitted light forms light-emitting points. Each reflective surface has a corresponding determined transmittance, and its corresponding displayed light intensity can be binary or multi-valued. Specifically, for example, the reflectivity can be in two states: zero and non-zero, corresponding to two kinds of emitted light intensities; or the reflectivity can be in three states: zero, maximum value, and half of the maximum value, corresponding to three kinds of emitted light intensities; and so on. The different transmittances can be achieved, for example, by using different areas of the reflective surface, or by using different reflectance coefficients of the reflective surface. Similarly, the arrangement of its static display units can also be in various possible ways. Taking a display unit that emits R, G, and B light as an example, along one dimension, its display units can be arranged in an RGBRGB… pattern (RGB repeats), or an RRR…GGG…BBB…RRR…GGG…BBB… pattern (RRR…GGG…BBB… repeats), or an arrangement of R, G, and B light-emitting points arranged in a triangle as a cycle, or a non-periodic arrangement, etc. Obviously, the color of the light emitted by the display unit can also be the C, M, Y, or K color of color printing (C is cyan, M is magenta, Y is yellow, and K is black). The color of the light emitted by each display unit can also be determined by the color of the corresponding incident backlight.

[0091] Furthermore, each static display unit may also be composed of multiple apertures (or multiple reflective surfaces), and the light intensity emitted by the display unit can be set by the combination of the number of apertures and / or their respective transmittances (or by the combination of the number of reflective surfaces and / or their respective reflectances).

[0092] The display unit array 10 can also be a transparent screen. In this case, the aforementioned compensation unit 202 can be used, such as... Figure 20The compensation unit 202, together with the cylindrical lens array, serves as a beam splitter 20 for a specific type of light (e.g., " The light represented by "·" exhibits a uniform refractive index plate, while the light with another polarization characteristic (such as the light represented by "·") exhibits a beam-splitting function. Each display unit emits the "·" light, and the beam-splitting grating 20 guides the light projected by each display unit to its corresponding transition viewing area. At this time, an additional polarization selection device 204 needs to be set between the display unit array 10 and the external environment. This polarization selection device 204 only allows the light carrying the polarization characteristic of "·" light from the ambient light to be polarized. "When characteristic light passes through, the beam splitter 20 acts as a plate with a uniform refractive index, allowing it to pass through and propagate to the observer. Alternatively, the beam splitter 20 can be a controllable device, such as a liquid crystal beam splitter; this liquid crystal beam splitter, driven by the control unit 40, can function as a beam splitter in one state and as a transparent plate with a uniform refractive index in another state, without beam splitting, such as..." Figure 21 As shown, the beam splitter grating 20 alternately presents two different states. When it presents a uniform transparent refractive index plate state, the display unit array 10 does not display light information, and ambient light passes through; when it presents a beam splitting function state, the display unit array 10 synchronously displays light information, and optimally blocks external ambient light by introducing a controllable blocking device 205.

[0093] Figure 1 In the diagram, the actual transition view area is distributed adjacent to the ground. It can also be represented by... Figure 22 The design shown achieves a view distribution with interspersed areas. Figure 22 In this array, each grating unit corresponds to a display unit and is designed as a discretely distributed block of display units. The display units of the display unit array 10 are divided into multiple display unit blocks along at least one direction, and each display unit block contains multiple display units. Figure 22 In the middle, along x The display units of the display unit array 10 are divided into multiple display unit blocks: B 1. B 2. B 3. B 4. B 5. ... The beam splitter grating 20 is formed along... x 'Axially arranged cylindrical lens grating units L 1. L 2. L 3. L 4. L 5. ... constitutes. Figure 22 For clarity, only some display unit blocks and some raster units are labeled; the numbers of the other display unit blocks and raster units can be clearly determined from their arrangement. Along x 'Direction, each grating unit corresponds toN b ≥2 display unit blocks, and the display unit blocks corresponding to the same raster unit, with ( n × N b The interval is ) display units, where n is a positive integer ≥ 1. The intervals are sequentially ( N b -1) All display unit blocks are grouped together, and their emitted light passes through their respective corresponding grating units at a distance of 10 from the display unit array. D At this point, a corresponding transition eyebox is formed. This type of transition eyebox is formed by the convergence of actual light beams and is named a real transition eyebox. N b Each display unit block group corresponds to a total of [number] generated [number] display unit blocks. N b A real transition eye box. Figure 22 Specifically N b =2 and n Taking =1 as an example, any grating unit corresponds to N b = 2 display unit blocks, and the same raster unit corresponds to N b =2 display unit blocks, interval ( n × N b = 2 display unit blocks. For example, raster unit. L 9 corresponds to N b =2 display unit blocks B 14 and B 17 Two display unit blocks are spaced apart in the middle. B 15 , B 16 After the light projected from a display unit block passes through the corresponding grating unit, the beams projected by each display unit cover a corresponding real transition eyebox. For example, a display unit block... B 17 The light projected by each display unit passes through the corresponding grating unit. L After 9, cover the transition eye box 1. Figure 22 midpoint O 9 is a grating unit L 9. (As shown in the image center.) Figure 22 As shown, point O 9 and display unit block B 17 The line connecting the edge points intersects the real transition eyebox 1 at two of its edge points. Similarly, the display unit blocks... B 3. B 5.B 7. B 9. B 11 , B 13 , B 15 ...projected beams, each passing through its corresponding grating unit... L 2. L 3. L 4. L 5. L 6. L 7. L 8. ...After emission, all are covered by the real transition eye box 1. Clearly, the display unit blocks corresponding to different grating units at the same point in time are different. Figure 22 In the diagram, the spacing between the grating units is set to... Δ Then the spacing between cell blocks will be displayed. D s = ( D + d )× Δ / ( N b × D )= D s-s / N b .in D s-s for N b Adjacent display unit blocks along x Towards the occupied size, D p The diameter of the observer's pupil. For a point within the real transition eyebox 1. VP Each display unit block corresponding to the eye box... B 3. B 5. B 7. B 9. B 11 , B 13 , B 15 , B 17 Each of the elements corresponds to a display unit, and the projected beams from their respective grating units converge at this point, which can serve as a viewpoint. VP .like Figure 22 As shown, displaying unit blocks... B 8. B 10 , B 12 , B 14 ,B 16 , B 18 ...corresponding to grating units respectively... L 6. L 9. L 8. L 9. L 10 , L 11 ... Figure 22 Only some raster units and some display units are labeled; the serial numbers of the other raster units and other display units can be clearly determined according to their arrangement order. Figure 22 The geometric relationships shown are similar to those of the unit blocks… B 8. B 10 , B 12 , B 14 , B 16 , B 18 ...projected beams, each passing through a corresponding grating unit... L 6. L 9. L 8. L 9. L 10 , L 11 The emitted beams, ..., all cover the real transition eyebox 2. A total of... N b = 2 real transition eye boxes. As mentioned above, the beam splitter grating 20 has a beam splitting control function: any grating unit corresponds to an interval ( n × N b ) display unit blocks N b A display unit block, the N b Each display unit block is covered by a beam of light projected by the grating unit, corresponding to one another. N b Each solid transition eye box, wherein one display unit block is covered by a projection beam from a corresponding grating unit, corresponding to one solid transition eye box; interval ( N b -1) All display unit blocks of a given display unit block, through the beams projected by their respective corresponding grating units, cover the same real transition eyebox. A viewing area within the real transition eyebox, such as the midpoint of real transition eyebox 1... VPThe field of view is illuminated by light beams projected from one display unit of each pixel block corresponding to the real transition eyebox 1. By designing the viewing area spacing within the same real transition eyebox to be smaller than the pupil diameter, 3D display can overcome focusing-convergence conflict when the real transition eyebox covers both pupils of the observer. Figure 22 The structure shown, relative to the viewing direction, displays the vertical direction of the unit array 10. z When there is a non-zero angle, the effective display depth of field can be increased by tilting the display unit array 10 relative to the viewing direction.

[0094] Furthermore, a projection unit 30 can be introduced to magnify the display unit array 10 and simultaneously form a real image of the real transition eyebox, serving as an effective eyebox. When the effective eyebox can cover both of the observer's eyes, and at least two light beams pass through a display point and enter either pupil, VAC-free display is achieved. In this case, the distance between the real transition viewing zones within the real transition eyebox is no longer necessarily smaller than the observer's pupil diameter in at least one direction.

[0095] Figure 23 Taking the virtual transitional viewing area as an example, its basic spectral splitting principle is similar to Figure 22 A virtual transition eyebox is formed by connecting the backward extensions of the light beams from a corresponding display unit through a grating unit, corresponding to the virtual transition viewing areas. Figure 23 The virtual transition eyeboxes 1 and 2. Each grating unit corresponds to... N b = 2 display unit blocks, and the same raster unit corresponds to N b =2 display unit blocks, interval ( n × N b = 2 display unit blocks. Then the projection unit 30 images the virtual transition eyebox into the corresponding effective eyebox, such as Figure 23 Effective eyeboxes 1 and 2. The beam splitter grating 20 has a beam splitting control function: any grating unit corresponds to an interval ( n × N b ) display unit blocks N b A display unit block, the N b Each display unit block is covered by the reverse extension line of the beam projected by the grating unit, corresponding to one another. N b Each virtual transition eyebox, wherein one display unit block covers one virtual transition eyebox via the reverse extension line of the beam projected by the corresponding grating unit; interval ( N b-1) All display unit blocks of a given display unit block, through the backward extension of the beams projected by their respective corresponding grating units, cover the same virtual transition eyebox. A viewing area within the virtual transition eyebox, such as the midpoint of virtual transition eyebox 1... VP The virtual transition viewing area is incident on the backward extension of the light beam projected from one of the pixel blocks of each display unit corresponding to the virtual transition eyebox 1. One viewing area in the virtual transition eyebox is imaged by the projection unit 30 as the corresponding effective viewing area. By designing the effective viewing area spacing within the same effective eyebox to be smaller than the pupil diameter, 3D display that overcomes the focusing-convergence conflict can be achieved. Figure 23 The structure shown is relative to the viewing direction. z The vertical direction of the display unit array 10 z 'Has a non-zero included angle' θ The effective display depth of field can be increased by tilting the display unit array 10 relative to the viewing direction.

[0096] The grating units of the aforementioned beam splitter grating 20 are typically arranged at equal intervals. However, in practice, the grating units can also be arranged at non-equal intervals. For example, the spacing between adjacent grating units can be a fixed value plus a random value to reduce the influence of moiré fringes.

[0097] The display units of each of the above-mentioned display unit arrays 10 are shown to be arranged in a planar manner. In fact, they can also be arranged in a curved manner.

[0098] Figure 7 and Figure 23 The system includes a projection unit 30. However, in this application, the projection unit 30 may not be necessary. For example, Figure 1 or Figure 22 In the optical structure shown, the display unit array 10 is designed to be tilted non-perpendicularly to the corresponding observation direction. That is, when different display units on the display unit array 10 are at different distances from the preset observation eye plane, the depth of field can be increased even in naked-eye VAC-free display. Obviously, the various related design schemes described in this application are also applicable to the case where the display unit array 10, or its image with respect to the projection section 30, is placed perpendicularly to the observation direction.

[0099] In this application, the display units can have various possible characteristics and arrangements. As long as more than one light beam passes through any display point and enters any pupil of the observer, VAC-free display can be guaranteed. In this application, a non-air medium, such as optical adhesive, can also be used to fill the space between the display unit array 10 and the beam splitter grating 20. The display unit array 10 can be a planar structure or a curved structure.

[0100] The above are merely preferred embodiments of this application, but the design concept of this application is not limited thereto. Any non-substantial modifications made to this application using this concept also fall within the protection scope of this application. For example, various possible and mutually identifiable optical characteristics can be selected as orthogonal characteristics of this patent. Accordingly, all related embodiments fall within the protection scope of this application.

Claims

1. A depth-enhanced autostereoscopic optical display system, characterized in that include: Display unit array (10), which includes multiple display units capable of independently projecting light information; The beam splitter (20) includes multiple grating units and is placed corresponding to the display unit array (10), so that the projected light from different display units or their reverse extensions are guided by their respective corresponding grating units to converge toward their respective transition viewing areas. The projection unit (30) is capable of forming a magnified virtual image of the display unit array (10) and a real image of each transition viewing area; The control unit (40) is connected to the display unit array (10) and is used to control the loading of light information by each display unit, which is the projection light information of the scene to be displayed along its corresponding projection vector. Among them, the projection vector corresponding to any display unit is the transmission path of the light beam projected by the corresponding grating unit and incident on the corresponding effective viewing area. The effective viewing area refers to the real image formed by the projection part (30) of each transitional viewing area. The optical display system is configured such that at least two light beams are incident on any observer's pupil within the effective viewing area, passing through any display point. Furthermore, on the display unit array (10), there are different display units, which correspond to different image distances via the projection part (30). The image of the display unit array (10) with respect to the projection part (30) is tilted non-perpendicularly to the observation direction.

2. The depth-enhanced autostereoscopic optical display system of claim 1, wherein, It also includes an aperture array (201), in which each aperture of the aperture array (201) is placed corresponding to each grating unit of the beam splitter (20) to adjust the light transmission aperture size of the corresponding grating unit.

3. The depth-enhanced autostereoscopic optical display system of claim 1, wherein, The beam splitter grating (20) is a cylindrical lens array, or a slit array, or a two-dimensional lens array, or a two-dimensional aperture array, or a two-dimensional micro / nano structure array. When the beam splitting grating (20) is a two-dimensional micro-nano structure array, the micro-nano structure units in the two-dimensional micro-nano structure array serve as grating units. Each micro-nano structure unit in the two-dimensional micro-nano structure array and each display unit in the display unit array (10) are placed in a one-to-one correspondence, guiding the light emitted from each corresponding display unit to be projected into the corresponding transition viewing area.

4. The depth-enhanced autostereoscopic optical display system of claim 1, wherein, The display unit is a minimum surface structure whose emitted light intensity can be independently adjusted.

5. The depth-enhanced autostereoscopic optical display system of claim 1, wherein, The display units of the display unit array (10) are located on different sub-screens, and adjacent sub-screens are not coplanar. The grating units corresponding to the different sub-screens form the beam splitting grating (20).

6. The depth-enhanced autostereoscopic optical display system of claim 5, wherein, At least one of the sub-screens is equipped with a corresponding grating unit.

7. The depth-enhanced autostereoscopic display system of claim 1, wherein, The position and spacing of the grating units of the beam splitter (20) are controlled to change under the drive of the control unit (40).

8. The depth-enhanced autostereoscopic optical display system of claim 1, wherein, When each grating unit has a corresponding focal length, its focal length can be controlled to change under the drive of the control unit (40).

9. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, Each of the O adjacent grating units corresponds to an O distinct orthogonal characteristic. Each grating unit allows the corresponding orthogonal characteristic light from the O orthogonal characteristic light to pass through, but blocks the other (O-1) non-corresponding orthogonal characteristic light, where O≥2.

10. The depth-enhanced true 3D optical display system according to claim 9, characterized in that, Each grating unit corresponds to a display unit block, and each display unit block emits orthogonal characteristic light corresponding to the grating unit.

11. The depth-enhanced true 3D optical display system according to claim 9, characterized in that, In the display unit array, along at least one direction, O adjacent display units respectively emit the O types of orthogonal characteristic light.

12. The depth-enhanced true 3D optical display system according to claim 9, characterized in that, The orthogonal characteristic is a linear polarization characteristic with mutually perpendicular polarization directions, or an optical rotation polarization characteristic composed of left-handed and right-handed polarization, or a frequency characteristic of different colors, or a temporal characteristic that allows light to pass through or emit light at different time points of the same time period, or a combination of two or more of the orthogonal characteristics.

13. The depth-enhanced true 3D optical display system according to claim 2, characterized in that, Each aperture of the aperture array (201) is composed of more than one sub-aperture, and each sub-aperture of the same aperture allows light with different orthogonal characteristics to pass through.

14. The depth-enhanced true 3D optical display system according to claim 13, characterized in that, Each sub-aperture of the same aperture opens at a different time point.

15. The depth-enhanced true 3D optical display system according to claim 13, characterized in that, Each sub-aperture of the same aperture allows light of different colors to pass through, or allows light with different polarization characteristics to pass through.

16. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, It also includes a directional backlight structure (60) that can cyclically and sequentially provide backlight to the display unit array (10) in different directions.

17. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, It also includes a directional backlight structure (60) that can provide backlight for the display unit array (10), the display unit array (10) is a reflective device, the beam splitter (20) does not have a beam splitting function for the incident backlight, but has a beam splitting function for the modulated outgoing light of the display unit array (10), the beam splitting function refers to the function of guiding the projected light of different display units or their reverse extension lines to converge towards their respective corresponding transition viewing areas.

18. The depth-enhanced true 3D optical display system according to claim 17, characterized in that, The beam splitter (20) is a composite structure of a cylindrical lens array and a compensation unit (202); The composite structure is a uniform refractive index plate for one type of characteristic light and a beam splitting function for another type of characteristic light. The incident backlight is the one type of characteristic light, and the display unit array (10) modulates the emitted light to be the other type of characteristic light. The beam splitting function refers to the function of guiding the projected light of different display units or their reverse extensions to converge towards their respective transition viewing areas.

19. The depth-enhanced true 3D optical display system according to claim 17, characterized in that, The beam splitter (20) is a micro-nano structure device. This micro-nano structure device has angle selectivity. It does not have a beam splitting function for incident backlight, but it has a beam splitting function for the modulated outgoing light of the display unit array (10) incident in other directions. This beam splitting function refers to the function of guiding the projected light of different display units or their reverse extension lines to converge towards their respective corresponding transition viewing areas.

20. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, The tilt angle formed by the display unit array (10) with respect to the image of the projection section (30) relative to the viewing direction. θ The range is 5° to 45°.

21. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, The display unit array (10) is a transparent device, the beam splitter (20) is a composite structure of a cylindrical lens array and a compensation unit (202), and the system also includes a polarization selection device (203). The composite structure acts as a uniform refractive index plate for one type of characteristic light and performs a beam splitting function for another type of characteristic light. The polarization selection device (203) only allows the one type of characteristic light component in the ambient light to pass through and be incident on the beam splitting grating (20), while blocking the other type of characteristic light. The beam splitting function refers to the function of guiding the projected light of different display units or their reverse extensions to converge towards their respective corresponding transition viewing areas.

22. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, The display unit array (10) is a transparent device. The beam splitter (20) can alternately present two different states under the drive of the control unit (40): a state with beam splitting function and a state without beam splitting function. The system also includes a controllable blocking device (205). When the beam splitter (20) presents a state without beam splitting function, the controllable blocking device (205) simultaneously allows external ambient light to enter the beam splitter (20). The display unit array (10) loads the off information only when the beam splitting grating (20) is in the state of beam splitting function. The beam splitting function refers to the function of guiding the projected light of different display units or their reverse extension lines to converge towards their respective transition viewing areas.

23. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, Each grating unit corresponds to N b A display unit block, which N b The beams projected by each display unit block, or their reverse extensions, respectively cover the corresponding areas. N b A transition eyebox, where positive integers N b ≥2; Wherein, the adjacent display unit block corresponding to any raster unit is ( n × N b ) display unit blocks are spaced apart, where positive integers n ≥1.

24. The depth-enhanced true 3D optical display system according to claim 23, characterized in that, The N b Each transition eyebox, with respect to the image of the projection section (30), serves as an effective eyebox; Among them, through N b The emitted light from at least two of the effective eye boxes covers both of the observer's eyes.

25. The depth-enhanced true 3D optical display system according to claim 23, characterized in that, It also includes a pupil tracking unit (70) connected to the control unit (40). Based on the position of the observer's eye determined by the pupil tracking unit (70), the control unit (40) can adjust the display unit corresponding to each grating unit to generate a corresponding effective eye box.

26. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, The projection part (30) is a single optical element or a combination of multiple optical elements.

27. The depth-enhanced true 3D optical display system according to claim 1, characterized in that, In the display unit array (10), the emitted light is guided to adjacent display units in different viewing areas. Along each arrangement direction of the display units, there are more than one adjacent display unit that emits light of the same color.

28. The depth-enhanced true 3D optical display system according to claim 27, characterized in that, The control unit (40) controls each display unit to load light information, which is the corresponding color component in the light information of the scene to be displayed, along its corresponding projection vector.

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